system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-11-05 18:23:50 +00:00
Code Issues Projects Releases Packages Wiki Activity
linux/net/sched/cls_bpf.c

496 lines
10 KiB
C
Raw Normal View History

net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
/*
* Berkeley Packet Filter based traffic classifier
*
* Might be used to classify traffic through flexible, user-defined and
* possibly JIT-ed BPF filters for traffic control as an alternative to
* ematches.
*
* (C) 2013 Daniel Borkmann <dborkman@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/filter.h>
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
#include <linux/bpf.h>
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
#include <net/sock.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
MODULE_DESCRIPTION("TC BPF based classifier");
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
#define CLS_BPF_NAME_LEN 256
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct cls_bpf_head {
struct list_head plist;
u32 hgen;
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct rcu_head rcu;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
};
struct cls_bpf_prog {
net: filter: split 'struct sk_filter' into socket and bpf parts clean up names related to socket filtering and bpf in the following way: - everything that deals with sockets keeps 'sk_*' prefix - everything that is pure BPF is changed to 'bpf_*' prefix split 'struct sk_filter' into struct sk_filter { atomic_t refcnt; struct rcu_head rcu; struct bpf_prog *prog; }; and struct bpf_prog { u32 jited:1, len:31; struct sock_fprog_kern *orig_prog; unsigned int (*bpf_func)(const struct sk_buff *skb, const struct bpf_insn *filter); union { struct sock_filter insns[0]; struct bpf_insn insnsi[0]; struct work_struct work; }; }; so that 'struct bpf_prog' can be used independent of sockets and cleans up 'unattached' bpf use cases split SK_RUN_FILTER macro into: SK_RUN_FILTER to be used with 'struct sk_filter *' and BPF_PROG_RUN to be used with 'struct bpf_prog *' __sk_filter_release(struct sk_filter *) gains __bpf_prog_release(struct bpf_prog *) helper function also perform related renames for the functions that work with 'struct bpf_prog *', since they're on the same lines: sk_filter_size -> bpf_prog_size sk_filter_select_runtime -> bpf_prog_select_runtime sk_filter_free -> bpf_prog_free sk_unattached_filter_create -> bpf_prog_create sk_unattached_filter_destroy -> bpf_prog_destroy sk_store_orig_filter -> bpf_prog_store_orig_filter sk_release_orig_filter -> bpf_release_orig_filter __sk_migrate_filter -> bpf_migrate_filter __sk_prepare_filter -> bpf_prepare_filter API for attaching classic BPF to a socket stays the same: sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *) and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program which is used by sockets, tun, af_packet API for 'unattached' BPF programs becomes: bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *) and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-31 03:34:16 +00:00
struct bpf_prog *filter;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct list_head link;
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
struct tcf_result res;
struct tcf_exts exts;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
u32 handle;
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
union {
u32 bpf_fd;
u16 bpf_num_ops;
};
struct sock_filter *bpf_ops;
const char *bpf_name;
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct tcf_proto *tp;
struct rcu_head rcu;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
};
static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
[TCA_BPF_CLASSID] = { .type = NLA_U32 },
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
[TCA_BPF_FD] = { .type = NLA_U32 },
[TCA_BPF_NAME] = { .type = NLA_NUL_STRING, .len = CLS_BPF_NAME_LEN },
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
[TCA_BPF_OPS_LEN] = { .type = NLA_U16 },
[TCA_BPF_OPS] = { .type = NLA_BINARY,
.len = sizeof(struct sock_filter) * BPF_MAXINSNS },
};
static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
net_sched: fix suspicious RCU usage in cls_bpf_classify() Fixes: commit 1f947bf151e90ec0baad2948 ("net: sched: rcu'ify cls_bpf") Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-15 21:21:50 +00:00
struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct cls_bpf_prog *prog;
cls_bpf: do eBPF invocation under non-bh RCU lock variant for maps Currently, it is possible in cls_bpf to access eBPF maps only under rcu_read_lock_bh() variants: while on ingress side, that is, handle_ing(), the classifier would be called from __netif_receive_skb_core() under rcu_read_lock(); on egress side, however, it's rcu_read_lock_bh() via __dev_queue_xmit(). This rcu/rcu_bh mix doesn't work together with eBPF maps as they require soley to be called under rcu_read_lock(). eBPF maps could also be shared among various other eBPF programs (possibly even with other eBPF program types, f.e. tracing) and user space processes, so any context is assumed. Therefore, a possible fix for cls_bpf is to wrap/nest eBPF program invocation under non-bh RCU lock variant. Fixes: e2e9b6541dd4 ("cls_bpf: add initial eBPF support for programmable classifiers") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-12 19:03:12 +00:00
int ret = -1;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
bpf: fix bpf helpers to use skb->mac_header relative offsets For the short-term solution, lets fix bpf helper functions to use skb->mac_header relative offsets instead of skb->data in order to get the same eBPF programs with cls_bpf and act_bpf work on ingress and egress qdisc path. We need to ensure that mac_header is set before calling into programs. This is effectively the first option from below referenced discussion. More long term solution for LD_ABS|LD_IND instructions will be more intrusive but also more beneficial than this, and implemented later as it's too risky at this point in time. I.e., we plan to look into the option of moving skb_pull() out of eth_type_trans() and into netif_receive_skb() as has been suggested as second option. Meanwhile, this solution ensures ingress can be used with eBPF, too, and that we won't run into ABI troubles later. For dealing with negative offsets inside eBPF helper functions, we've implemented bpf_skb_clone_unwritable() to test for unwriteable headers. Reference: http://thread.gmane.org/gmane.linux.network/359129/focus=359694 Fixes: 608cd71a9c7c ("tc: bpf: generalize pedit action") Fixes: 91bc4822c3d6 ("tc: bpf: add checksum helpers") Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-04-15 19:55:45 +00:00
if (unlikely(!skb_mac_header_was_set(skb)))
return -1;
cls_bpf: do eBPF invocation under non-bh RCU lock variant for maps Currently, it is possible in cls_bpf to access eBPF maps only under rcu_read_lock_bh() variants: while on ingress side, that is, handle_ing(), the classifier would be called from __netif_receive_skb_core() under rcu_read_lock(); on egress side, however, it's rcu_read_lock_bh() via __dev_queue_xmit(). This rcu/rcu_bh mix doesn't work together with eBPF maps as they require soley to be called under rcu_read_lock(). eBPF maps could also be shared among various other eBPF programs (possibly even with other eBPF program types, f.e. tracing) and user space processes, so any context is assumed. Therefore, a possible fix for cls_bpf is to wrap/nest eBPF program invocation under non-bh RCU lock variant. Fixes: e2e9b6541dd4 ("cls_bpf: add initial eBPF support for programmable classifiers") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-12 19:03:12 +00:00
/* Needed here for accessing maps. */
rcu_read_lock();
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
list_for_each_entry_rcu(prog, &head->plist, link) {
net: filter: split 'struct sk_filter' into socket and bpf parts clean up names related to socket filtering and bpf in the following way: - everything that deals with sockets keeps 'sk_*' prefix - everything that is pure BPF is changed to 'bpf_*' prefix split 'struct sk_filter' into struct sk_filter { atomic_t refcnt; struct rcu_head rcu; struct bpf_prog *prog; }; and struct bpf_prog { u32 jited:1, len:31; struct sock_fprog_kern *orig_prog; unsigned int (*bpf_func)(const struct sk_buff *skb, const struct bpf_insn *filter); union { struct sock_filter insns[0]; struct bpf_insn insnsi[0]; struct work_struct work; }; }; so that 'struct bpf_prog' can be used independent of sockets and cleans up 'unattached' bpf use cases split SK_RUN_FILTER macro into: SK_RUN_FILTER to be used with 'struct sk_filter *' and BPF_PROG_RUN to be used with 'struct bpf_prog *' __sk_filter_release(struct sk_filter *) gains __bpf_prog_release(struct bpf_prog *) helper function also perform related renames for the functions that work with 'struct bpf_prog *', since they're on the same lines: sk_filter_size -> bpf_prog_size sk_filter_select_runtime -> bpf_prog_select_runtime sk_filter_free -> bpf_prog_free sk_unattached_filter_create -> bpf_prog_create sk_unattached_filter_destroy -> bpf_prog_destroy sk_store_orig_filter -> bpf_prog_store_orig_filter sk_release_orig_filter -> bpf_release_orig_filter __sk_migrate_filter -> bpf_migrate_filter __sk_prepare_filter -> bpf_prepare_filter API for attaching classic BPF to a socket stays the same: sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *) and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program which is used by sockets, tun, af_packet API for 'unattached' BPF programs becomes: bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *) and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-31 03:34:16 +00:00
int filter_res = BPF_PROG_RUN(prog->filter, skb);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
if (filter_res == 0)
continue;
*res = prog->res;
if (filter_res != -1)
res->classid = filter_res;
ret = tcf_exts_exec(skb, &prog->exts, res);
if (ret < 0)
continue;
cls_bpf: do eBPF invocation under non-bh RCU lock variant for maps Currently, it is possible in cls_bpf to access eBPF maps only under rcu_read_lock_bh() variants: while on ingress side, that is, handle_ing(), the classifier would be called from __netif_receive_skb_core() under rcu_read_lock(); on egress side, however, it's rcu_read_lock_bh() via __dev_queue_xmit(). This rcu/rcu_bh mix doesn't work together with eBPF maps as they require soley to be called under rcu_read_lock(). eBPF maps could also be shared among various other eBPF programs (possibly even with other eBPF program types, f.e. tracing) and user space processes, so any context is assumed. Therefore, a possible fix for cls_bpf is to wrap/nest eBPF program invocation under non-bh RCU lock variant. Fixes: e2e9b6541dd4 ("cls_bpf: add initial eBPF support for programmable classifiers") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-12 19:03:12 +00:00
break;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
}
cls_bpf: do eBPF invocation under non-bh RCU lock variant for maps Currently, it is possible in cls_bpf to access eBPF maps only under rcu_read_lock_bh() variants: while on ingress side, that is, handle_ing(), the classifier would be called from __netif_receive_skb_core() under rcu_read_lock(); on egress side, however, it's rcu_read_lock_bh() via __dev_queue_xmit(). This rcu/rcu_bh mix doesn't work together with eBPF maps as they require soley to be called under rcu_read_lock(). eBPF maps could also be shared among various other eBPF programs (possibly even with other eBPF program types, f.e. tracing) and user space processes, so any context is assumed. Therefore, a possible fix for cls_bpf is to wrap/nest eBPF program invocation under non-bh RCU lock variant. Fixes: e2e9b6541dd4 ("cls_bpf: add initial eBPF support for programmable classifiers") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-12 19:03:12 +00:00
rcu_read_unlock();
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
cls_bpf: do eBPF invocation under non-bh RCU lock variant for maps Currently, it is possible in cls_bpf to access eBPF maps only under rcu_read_lock_bh() variants: while on ingress side, that is, handle_ing(), the classifier would be called from __netif_receive_skb_core() under rcu_read_lock(); on egress side, however, it's rcu_read_lock_bh() via __dev_queue_xmit(). This rcu/rcu_bh mix doesn't work together with eBPF maps as they require soley to be called under rcu_read_lock(). eBPF maps could also be shared among various other eBPF programs (possibly even with other eBPF program types, f.e. tracing) and user space processes, so any context is assumed. Therefore, a possible fix for cls_bpf is to wrap/nest eBPF program invocation under non-bh RCU lock variant. Fixes: e2e9b6541dd4 ("cls_bpf: add initial eBPF support for programmable classifiers") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-12 19:03:12 +00:00
return ret;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
}
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
{
return !prog->bpf_ops;
}
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
static int cls_bpf_init(struct tcf_proto *tp)
{
struct cls_bpf_head *head;
head = kzalloc(sizeof(*head), GFP_KERNEL);
if (head == NULL)
return -ENOBUFS;
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
INIT_LIST_HEAD_RCU(&head->plist);
rcu_assign_pointer(tp->root, head);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
return 0;
}
static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog)
{
net_sched: remove the first parameter from tcf_exts_destroy() Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim <hadi@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-25 17:26:37 +00:00
tcf_exts_destroy(&prog->exts);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
if (cls_bpf_is_ebpf(prog))
bpf_prog_put(prog->filter);
else
bpf_prog_destroy(prog->filter);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
kfree(prog->bpf_name);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
kfree(prog->bpf_ops);
kfree(prog);
}
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
static void __cls_bpf_delete_prog(struct rcu_head *rcu)
{
struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
cls_bpf_delete_prog(prog->tp, prog);
}
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg)
{
net_sched: cls_bpf: remove unnecessary iteration and use passed arg Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-02 17:00:32 +00:00
struct cls_bpf_prog *prog = (struct cls_bpf_prog *) arg;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
net_sched: cls_bpf: remove unnecessary iteration and use passed arg Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-02 17:00:32 +00:00
list_del_rcu(&prog->link);
tcf_unbind_filter(tp, &prog->res);
call_rcu(&prog->rcu, __cls_bpf_delete_prog);
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
net_sched: cls_bpf: remove unnecessary iteration and use passed arg Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-02 17:00:32 +00:00
return 0;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
}
net_sched: destroy proto tp when all filters are gone Kernel automatically creates a tp for each (kind, protocol, priority) tuple, which has handle 0, when we add a new filter, but it still is left there after we remove our own, unless we don't specify the handle (literally means all the filters under the tuple). For example this one is left: # tc filter show dev eth0 filter parent 8001: protocol arp pref 49152 basic The user-space is hard to clean up these for kernel because filters like u32 are organized in a complex way. So kernel is responsible to remove it after all filters are gone. Each type of filter has its own way to store the filters, so each type has to provide its way to check if all filters are gone. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim<jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-06 19:47:59 +00:00
static bool cls_bpf_destroy(struct tcf_proto *tp, bool force)
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
{
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct cls_bpf_head *head = rtnl_dereference(tp->root);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct cls_bpf_prog *prog, *tmp;
net_sched: destroy proto tp when all filters are gone Kernel automatically creates a tp for each (kind, protocol, priority) tuple, which has handle 0, when we add a new filter, but it still is left there after we remove our own, unless we don't specify the handle (literally means all the filters under the tuple). For example this one is left: # tc filter show dev eth0 filter parent 8001: protocol arp pref 49152 basic The user-space is hard to clean up these for kernel because filters like u32 are organized in a complex way. So kernel is responsible to remove it after all filters are gone. Each type of filter has its own way to store the filters, so each type has to provide its way to check if all filters are gone. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim<jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-06 19:47:59 +00:00
if (!force && !list_empty(&head->plist))
return false;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
list_for_each_entry_safe(prog, tmp, &head->plist, link) {
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
list_del_rcu(&prog->link);
net: sched: do not use tcf_proto 'tp' argument from call_rcu Using the tcf_proto pointer 'tp' from inside the classifiers callback is not valid because it may have been cleaned up by another call_rcu occuring on another CPU. 'tp' is currently being used by tcf_unbind_filter() in this patch we move instances of tcf_unbind_filter outside of the call_rcu() context. This is safe to do because any running schedulers will either read the valid class field or it will be zeroed. And all schedulers today when the class is 0 do a lookup using the same call used by the tcf_exts_bind(). So even if we have a running classifier hit the null class pointer it will do a lookup and get to the same result. This is particularly fragile at the moment because the only way to verify this is to audit the schedulers call sites. Reported-by: Cong Wang <xiyou.wangconf@gmail.com> Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Cong Wang <cwang@twopensource.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-06 04:28:52 +00:00
tcf_unbind_filter(tp, &prog->res);
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
call_rcu(&prog->rcu, __cls_bpf_delete_prog);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
}
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
RCU_INIT_POINTER(tp->root, NULL);
kfree_rcu(head, rcu);
net_sched: destroy proto tp when all filters are gone Kernel automatically creates a tp for each (kind, protocol, priority) tuple, which has handle 0, when we add a new filter, but it still is left there after we remove our own, unless we don't specify the handle (literally means all the filters under the tuple). For example this one is left: # tc filter show dev eth0 filter parent 8001: protocol arp pref 49152 basic The user-space is hard to clean up these for kernel because filters like u32 are organized in a complex way. So kernel is responsible to remove it after all filters are gone. Each type of filter has its own way to store the filters, so each type has to provide its way to check if all filters are gone. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim<jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-06 19:47:59 +00:00
return true;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
}
static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
{
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct cls_bpf_head *head = rtnl_dereference(tp->root);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct cls_bpf_prog *prog;
unsigned long ret = 0UL;
if (head == NULL)
return 0UL;
net_sched: cls_bpf: remove faulty use of list_for_each_entry_rcu rcu variant is not correct here. The code is called by updater (rtnl lock is held), not by reader (no rcu_read_lock is held). Signed-off-by: Jiri Pirko <jiri@resnulli.us> ACKed-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-02 17:00:33 +00:00
list_for_each_entry(prog, &head->plist, link) {
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
if (prog->handle == handle) {
ret = (unsigned long) prog;
break;
}
}
return ret;
}
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
static int cls_bpf_prog_from_ops(struct nlattr **tb,
struct cls_bpf_prog *prog, u32 classid)
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
{
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct sock_filter *bpf_ops;
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
struct sock_fprog_kern fprog_tmp;
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct bpf_prog *fp;
tc: cls_bpf: rename bpf_len to bpf_num_ops It was suggested by DaveM to change the name as "len" might indicate unit bytes. Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-15 08:52:40 +00:00
u16 bpf_size, bpf_num_ops;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
int ret;
tc: cls_bpf: rename bpf_len to bpf_num_ops It was suggested by DaveM to change the name as "len" might indicate unit bytes. Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-15 08:52:40 +00:00
bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
return -EINVAL;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
tc: cls_bpf: rename bpf_len to bpf_num_ops It was suggested by DaveM to change the name as "len" might indicate unit bytes. Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-15 08:52:40 +00:00
bpf_size = bpf_num_ops * sizeof(*bpf_ops);
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
return -EINVAL;
net: cls_bpf: fix size mismatch on filter preparation In cls_bpf_modify_existing(), we read out the number of filter blocks, do some sanity checks, allocate a block on that size, and copy over the BPF instruction blob from user space, then pass everything through the classic BPF checker prior to installation of the classifier. We should reject mismatches here, there are 2 scenarios: the number of filter blocks could be smaller than the provided instruction blob, so we do a partial copy of the BPF program, and thus the instructions will either be rejected from the verifier or a valid BPF program will be run; in the other case, we'll end up copying more than we're supposed to, and most likely the trailing garbage will be rejected by the verifier as well (i.e. we need to fit instruction pattern, ret {A,K} needs to be last instruction, load/stores must be correct, etc); in case not, we would leak memory when dumping back instruction patterns. The code should have only used nla_len() as Dave noted to avoid this from the beginning. Anyway, lets fix it by rejecting such load attempts. Fixes: 7d1d65cb84e1 ("net: sched: cls_bpf: add BPF-based classifier") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-22 09:41:01 +00:00
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
if (bpf_ops == NULL)
return -ENOMEM;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
fprog_tmp.len = bpf_num_ops;
fprog_tmp.filter = bpf_ops;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
ret = bpf_prog_create(&fp, &fprog_tmp);
if (ret < 0) {
kfree(bpf_ops);
return ret;
}
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
prog->bpf_ops = bpf_ops;
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
prog->bpf_num_ops = bpf_num_ops;
prog->bpf_name = NULL;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
prog->filter = fp;
prog->res.classid = classid;
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
return 0;
}
static int cls_bpf_prog_from_efd(struct nlattr **tb,
struct cls_bpf_prog *prog, u32 classid)
{
struct bpf_prog *fp;
char *name = NULL;
u32 bpf_fd;
bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
fp = bpf_prog_get(bpf_fd);
if (IS_ERR(fp))
return PTR_ERR(fp);
if (fp->type != BPF_PROG_TYPE_SCHED_CLS) {
bpf_prog_put(fp);
return -EINVAL;
}
if (tb[TCA_BPF_NAME]) {
name = kmemdup(nla_data(tb[TCA_BPF_NAME]),
nla_len(tb[TCA_BPF_NAME]),
GFP_KERNEL);
if (!name) {
bpf_prog_put(fp);
return -ENOMEM;
}
}
prog->bpf_ops = NULL;
prog->bpf_fd = bpf_fd;
prog->bpf_name = name;
prog->filter = fp;
prog->res.classid = classid;
return 0;
}
static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
struct cls_bpf_prog *prog,
unsigned long base, struct nlattr **tb,
struct nlattr *est, bool ovr)
{
struct tcf_exts exts;
bool is_bpf, is_ebpf;
u32 classid;
int ret;
is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
is_ebpf = tb[TCA_BPF_FD];
if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf) ||
!tb[TCA_BPF_CLASSID])
return -EINVAL;
tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE);
ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr);
if (ret < 0)
return ret;
classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog, classid) :
cls_bpf_prog_from_efd(tb, prog, classid);
if (ret < 0) {
tcf_exts_destroy(&exts);
return ret;
}
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
tcf_bind_filter(tp, &prog->res, base);
tcf_exts_change(tp, &prog->exts, &exts);
return 0;
}
static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
struct cls_bpf_head *head)
{
unsigned int i = 0x80000000;
net: cls_bpf: fix auto generation of per list handles When creating a bpf classifier in tc with priority collisions and invoking automatic unique handle assignment, cls_bpf_grab_new_handle() will return a wrong handle id which in fact is non-unique. Usually altering of specific filters is being addressed over major id, but in case of collisions we result in a filter chain, where handle ids address individual cls_bpf_progs inside the classifier. Issue is, in cls_bpf_grab_new_handle() we probe for head->hgen handle in cls_bpf_get() and in case we found a free handle, we're supposed to use exactly head->hgen. In case of insufficient numbers of handles, we bail out later as handle id 0 is not allowed. Fixes: 7d1d65cb84e1 ("net: sched: cls_bpf: add BPF-based classifier") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-22 09:41:02 +00:00
u32 handle;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
do {
if (++head->hgen == 0x7FFFFFFF)
head->hgen = 1;
} while (--i > 0 && cls_bpf_get(tp, head->hgen));
net: cls_bpf: fix auto generation of per list handles When creating a bpf classifier in tc with priority collisions and invoking automatic unique handle assignment, cls_bpf_grab_new_handle() will return a wrong handle id which in fact is non-unique. Usually altering of specific filters is being addressed over major id, but in case of collisions we result in a filter chain, where handle ids address individual cls_bpf_progs inside the classifier. Issue is, in cls_bpf_grab_new_handle() we probe for head->hgen handle in cls_bpf_get() and in case we found a free handle, we're supposed to use exactly head->hgen. In case of insufficient numbers of handles, we bail out later as handle id 0 is not allowed. Fixes: 7d1d65cb84e1 ("net: sched: cls_bpf: add BPF-based classifier") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-22 09:41:02 +00:00
if (unlikely(i == 0)) {
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
pr_err("Insufficient number of handles\n");
net: cls_bpf: fix auto generation of per list handles When creating a bpf classifier in tc with priority collisions and invoking automatic unique handle assignment, cls_bpf_grab_new_handle() will return a wrong handle id which in fact is non-unique. Usually altering of specific filters is being addressed over major id, but in case of collisions we result in a filter chain, where handle ids address individual cls_bpf_progs inside the classifier. Issue is, in cls_bpf_grab_new_handle() we probe for head->hgen handle in cls_bpf_get() and in case we found a free handle, we're supposed to use exactly head->hgen. In case of insufficient numbers of handles, we bail out later as handle id 0 is not allowed. Fixes: 7d1d65cb84e1 ("net: sched: cls_bpf: add BPF-based classifier") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-22 09:41:02 +00:00
handle = 0;
} else {
handle = head->hgen;
}
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
net: cls_bpf: fix auto generation of per list handles When creating a bpf classifier in tc with priority collisions and invoking automatic unique handle assignment, cls_bpf_grab_new_handle() will return a wrong handle id which in fact is non-unique. Usually altering of specific filters is being addressed over major id, but in case of collisions we result in a filter chain, where handle ids address individual cls_bpf_progs inside the classifier. Issue is, in cls_bpf_grab_new_handle() we probe for head->hgen handle in cls_bpf_get() and in case we found a free handle, we're supposed to use exactly head->hgen. In case of insufficient numbers of handles, we bail out later as handle id 0 is not allowed. Fixes: 7d1d65cb84e1 ("net: sched: cls_bpf: add BPF-based classifier") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-22 09:41:02 +00:00
return handle;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
}
static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
struct tcf_proto *tp, unsigned long base,
u32 handle, struct nlattr **tca,
sched, cls: check if we could overwrite actions when changing a filter When actions are attached to a filter, they are a part of the filter itself, so when changing a filter we should allow to overwrite the actions inside as well. In my specific case, when I tried to _append_ a new action to an existing filter which already has an action, I got EEXIST since kernel refused to overwrite the existing one in kernel. This patch checks if we are changing the filter checking NLM_F_CREATE flag (Sigh, filters don't use NLM_F_REPLACE...) and then passes the boolean down to actions. This fixes the problem above. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-25 20:54:06 +00:00
unsigned long *arg, bool ovr)
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
{
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct cls_bpf_head *head = rtnl_dereference(tp->root);
struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct nlattr *tb[TCA_BPF_MAX + 1];
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct cls_bpf_prog *prog;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
int ret;
if (tca[TCA_OPTIONS] == NULL)
return -EINVAL;
ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy);
if (ret < 0)
return ret;
prog = kzalloc(sizeof(*prog), GFP_KERNEL);
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
if (!prog)
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
return -ENOBUFS;
net_sched: cls: refactor out struct tcf_ext_map These information can be saved in tcf_exts, and this will simplify the code. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-16 04:15:07 +00:00
tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
if (oldprog) {
if (handle && oldprog->handle != handle) {
ret = -EINVAL;
goto errout;
}
}
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
if (handle == 0)
prog->handle = cls_bpf_grab_new_handle(tp, head);
else
prog->handle = handle;
if (prog->handle == 0) {
ret = -EINVAL;
goto errout;
}
sched, cls: check if we could overwrite actions when changing a filter When actions are attached to a filter, they are a part of the filter itself, so when changing a filter we should allow to overwrite the actions inside as well. In my specific case, when I tried to _append_ a new action to an existing filter which already has an action, I got EEXIST since kernel refused to overwrite the existing one in kernel. This patch checks if we are changing the filter checking NLM_F_CREATE flag (Sigh, filters don't use NLM_F_REPLACE...) and then passes the boolean down to actions. This fixes the problem above. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-25 20:54:06 +00:00
ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
if (ret < 0)
goto errout;
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
if (oldprog) {
list_replace_rcu(&prog->link, &oldprog->link);
net: sched: do not use tcf_proto 'tp' argument from call_rcu Using the tcf_proto pointer 'tp' from inside the classifiers callback is not valid because it may have been cleaned up by another call_rcu occuring on another CPU. 'tp' is currently being used by tcf_unbind_filter() in this patch we move instances of tcf_unbind_filter outside of the call_rcu() context. This is safe to do because any running schedulers will either read the valid class field or it will be zeroed. And all schedulers today when the class is 0 do a lookup using the same call used by the tcf_exts_bind(). So even if we have a running classifier hit the null class pointer it will do a lookup and get to the same result. This is particularly fragile at the moment because the only way to verify this is to audit the schedulers call sites. Reported-by: Cong Wang <xiyou.wangconf@gmail.com> Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Cong Wang <cwang@twopensource.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-06 04:28:52 +00:00
tcf_unbind_filter(tp, &oldprog->res);
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
call_rcu(&oldprog->rcu, __cls_bpf_delete_prog);
} else {
list_add_rcu(&prog->link, &head->plist);
}
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
*arg = (unsigned long) prog;
return 0;
errout:
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
kfree(prog);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
return ret;
}
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
struct sk_buff *skb)
{
struct nlattr *nla;
if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
return -EMSGSIZE;
nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
sizeof(struct sock_filter));
if (nla == NULL)
return -EMSGSIZE;
memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
return 0;
}
static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
struct sk_buff *skb)
{
if (nla_put_u32(skb, TCA_BPF_FD, prog->bpf_fd))
return -EMSGSIZE;
if (prog->bpf_name &&
nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
return -EMSGSIZE;
return 0;
}
net_sched: add struct net pointer to tcf_proto_ops->dump It will be needed by the next patch. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-10 00:14:01 +00:00
static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct sk_buff *skb, struct tcmsg *tm)
{
struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh;
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
struct nlattr *nest;
int ret;
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
if (prog == NULL)
return skb->len;
tm->tcm_handle = prog->handle;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
if (nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
goto nla_put_failure;
cls_bpf: add initial eBPF support for programmable classifiers This work extends the "classic" BPF programmable tc classifier by extending its scope also to native eBPF code! This allows for user space to implement own custom, 'safe' C like classifiers (or whatever other frontend language LLVM et al may provide in future), that can then be compiled with the LLVM eBPF backend to an eBPF elf file. The result of this can be loaded into the kernel via iproute2's tc. In the kernel, they can be JITed on major archs and thus run in native performance. Simple, minimal toy example to demonstrate the workflow: #include <linux/ip.h> #include <linux/if_ether.h> #include <linux/bpf.h> #include "tc_bpf_api.h" __section("classify") int cls_main(struct sk_buff *skb) { return (0x800 << 16) | load_byte(skb, ETH_HLEN + __builtin_offsetof(struct iphdr, tos)); } char __license[] __section("license") = "GPL"; The classifier can then be compiled into eBPF opcodes and loaded via tc, for example: clang -O2 -emit-llvm -c cls.c -o - | llc -march=bpf -filetype=obj -o cls.o tc filter add dev em1 parent 1: bpf cls.o [...] As it has been demonstrated, the scope can even reach up to a fully fledged flow dissector (similarly as in samples/bpf/sockex2_kern.c). For tc, maps are allowed to be used, but from kernel context only, in other words, eBPF code can keep state across filter invocations. In future, we perhaps may reattach from a different application to those maps e.g., to read out collected statistics/state. Similarly as in socket filters, we may extend functionality for eBPF classifiers over time depending on the use cases. For that purpose, cls_bpf programs are using BPF_PROG_TYPE_SCHED_CLS program type, so we can allow additional functions/accessors (e.g. an ABI compatible offset translation to skb fields/metadata). For an initial cls_bpf support, we allow the same set of helper functions as eBPF socket filters, but we could diverge at some point in time w/o problem. I was wondering whether cls_bpf and act_bpf could share C programs, I can imagine that at some point, we introduce i) further common handlers for both (or even beyond their scope), and/or if truly needed ii) some restricted function space for each of them. Both can be abstracted easily through struct bpf_verifier_ops in future. The context of cls_bpf versus act_bpf is slightly different though: a cls_bpf program will return a specific classid whereas act_bpf a drop/non-drop return code, latter may also in future mangle skbs. That said, we can surely have a "classify" and "action" section in a single object file, or considered mentioned constraint add a possibility of a shared section. The workflow for getting native eBPF running from tc [1] is as follows: for f_bpf, I've added a slightly modified ELF parser code from Alexei's kernel sample, which reads out the LLVM compiled object, sets up maps (and dynamically fixes up map fds) if any, and loads the eBPF instructions all centrally through the bpf syscall. The resulting fd from the loaded program itself is being passed down to cls_bpf, which looks up struct bpf_prog from the fd store, and holds reference, so that it stays available also after tc program lifetime. On tc filter destruction, it will then drop its reference. Moreover, I've also added the optional possibility to annotate an eBPF filter with a name (e.g. path to object file, or something else if preferred) so that when tc dumps currently installed filters, some more context can be given to an admin for a given instance (as opposed to just the file descriptor number). Last but not least, bpf_prog_get() and bpf_prog_put() needed to be exported, so that eBPF can be used from cls_bpf built as a module. Thanks to 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") I think this is of no concern since anything wanting to alter eBPF opcode after verification stage would crash the kernel. [1] http://git.breakpoint.cc/cgit/dborkman/iproute2.git/log/?h=ebpf Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-01 11:31:48 +00:00
if (cls_bpf_is_ebpf(prog))
ret = cls_bpf_dump_ebpf_info(prog, skb);
else
ret = cls_bpf_dump_bpf_info(prog, skb);
if (ret)
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
goto nla_put_failure;
net_sched: cls: refactor out struct tcf_ext_map These information can be saved in tcf_exts, and this will simplify the code. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-16 04:15:07 +00:00
if (tcf_exts_dump(skb, &prog->exts) < 0)
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
goto nla_put_failure;
nla_nest_end(skb, nest);
net_sched: cls: refactor out struct tcf_ext_map These information can be saved in tcf_exts, and this will simplify the code. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-16 04:15:07 +00:00
if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
goto nla_put_failure;
return skb->len;
nla_put_failure:
nla_nest_cancel(skb, nest);
return -1;
}
static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
net: sched: rcu'ify cls_bpf This patch makes the cls_bpf classifier RCU safe. The tcf_lock was being used to protect a list of cls_bpf_prog now this list is RCU safe and updates occur with rcu_replace. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-13 03:10:24 +00:00
struct cls_bpf_head *head = rtnl_dereference(tp->root);
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
struct cls_bpf_prog *prog;
net_sched: cls_bpf: remove faulty use of list_for_each_entry_rcu rcu variant is not correct here. The code is called by updater (rtnl lock is held), not by reader (no rcu_read_lock is held). Signed-off-by: Jiri Pirko <jiri@resnulli.us> ACKed-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-02 17:00:33 +00:00
list_for_each_entry(prog, &head->plist, link) {
net: sched: cls_bpf: add BPF-based classifier This work contains a lightweight BPF-based traffic classifier that can serve as a flexible alternative to ematch-based tree classification, i.e. now that BPF filter engine can also be JITed in the kernel. Naturally, tc actions and policies are supported as well with cls_bpf. Multiple BPF programs/filter can be attached for a class, or they can just as well be written within a single BPF program, that's really up to the user how he wishes to run/optimize the code, e.g. also for inversion of verdicts etc. The notion of a BPF program's return/exit codes is being kept as follows: 0: No match -1: Select classid given in "tc filter ..." command else: flowid, overwrite the default one As a minimal usage example with iproute2, we use a 3 band prio root qdisc on a router with sfq each as leave, and assign ssh and icmp bpf-based filters to band 1, http traffic to band 2 and the rest to band 3. For the first two bands we load the bytecode from a file, in the 2nd we load it inline as an example: echo 1 > /proc/sys/net/core/bpf_jit_enable tc qdisc del dev em1 root tc qdisc add dev em1 root handle 1: prio bands 3 priomap 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 tc qdisc add dev em1 parent 1:1 sfq perturb 16 tc qdisc add dev em1 parent 1:2 sfq perturb 16 tc qdisc add dev em1 parent 1:3 sfq perturb 16 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/ssh.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/icmp.bpf flowid 1:1 tc filter add dev em1 parent 1: bpf run bytecode-file /etc/tc/http.bpf flowid 1:2 tc filter add dev em1 parent 1: bpf run bytecode "`bpfc -f tc -i misc.ops`" flowid 1:3 BPF programs can be easily created and passed to tc, either as inline 'bytecode' or 'bytecode-file'. There are a couple of front-ends that can compile opcodes, for example: 1) People familiar with tcpdump-like filters: tcpdump -iem1 -ddd port 22 | tr '\n' ',' > /etc/tc/ssh.bpf 2) People that want to low-level program their filters or use BPF extensions that lack support by libpcap's compiler: bpfc -f tc -i ssh.ops > /etc/tc/ssh.bpf ssh.ops example code: ldh [12] jne #0x800, drop ldb [23] jneq #6, drop ldh [20] jset #0x1fff, drop ldxb 4 * ([14] & 0xf) ldh [%x + 14] jeq #0x16, pass ldh [%x + 16] jne #0x16, drop pass: ret #-1 drop: ret #0 It was chosen to load bytecode into tc, since the reverse operation, tc filter list dev em1, is then able to show the exact commands again. Possible follow-up work could also include a small expression compiler for iproute2. Tested with the help of bmon. This idea came up during the Netfilter Workshop 2013 in Copenhagen. Also thanks to feedback from Eric Dumazet! Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-28 15:43:02 +00:00
if (arg->count < arg->skip)
goto skip;
if (arg->fn(tp, (unsigned long) prog, arg) < 0) {
arg->stop = 1;
break;
}
skip:
arg->count++;
}
}
static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
.kind = "bpf",
.owner = THIS_MODULE,
.classify = cls_bpf_classify,
.init = cls_bpf_init,
.destroy = cls_bpf_destroy,
.get = cls_bpf_get,
.change = cls_bpf_change,
.delete = cls_bpf_delete,
.walk = cls_bpf_walk,
.dump = cls_bpf_dump,
};
static int __init cls_bpf_init_mod(void)
{
return register_tcf_proto_ops(&cls_bpf_ops);
}
static void __exit cls_bpf_exit_mod(void)
{
unregister_tcf_proto_ops(&cls_bpf_ops);
}
module_init(cls_bpf_init_mod);
module_exit(cls_bpf_exit_mod);
Reference in a new issue Copy permalink