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https://github.com/torvalds/linux
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ee28906fd7
Since commit4895c771c7("ipv4: Add FIB nexthop exceptions."), cached exception routes are stored as a separate entity, so they are not dumped on a FIB dump, even if the RTM_F_CLONED flag is passed. This implies that the command 'ip route list cache' doesn't return any result anymore. If the RTM_F_CLONED is passed, and strict checking requested, retrieve nexthop exception routes and dump them. If no strict checking is requested, filtering can't be performed consistently: dump everything in that case. With this, we need to add an argument to the netlink callback in order to track how many entries were already dumped for the last leaf included in a partial netlink dump. A single additional argument is sufficient, even if we traverse logically nested structures (nexthop objects, hash table buckets, bucket chains): it doesn't matter if we stop in the middle of any of those, because they are always traversed the same way. As an example, s_i values in [], s_fa values in (): node (fa) #1 [1] nexthop #1 bucket #1 -> #0 in chain (1) bucket #2 -> #0 in chain (2) -> #1 in chain (3) -> #2 in chain (4) bucket #3 -> #0 in chain (5) -> #1 in chain (6) nexthop #2 bucket #1 -> #0 in chain (7) -> #1 in chain (8) bucket #2 -> #0 in chain (9) -- node (fa) #2 [2] nexthop #1 bucket #1 -> #0 in chain (1) -> #1 in chain (2) bucket #2 -> #0 in chain (3) it doesn't matter if we stop at (3), (4), (7) for "node #1", or at (2) for "node #2": walking flattens all that. It would even be possible to drop the distinction between the in-tree (s_i) and in-node (s_fa) counter, but a further improvement might advise against this. This is only as accurate as the existing tracking mechanism for leaves: if a partial dump is restarted after exceptions are removed or expired, we might skip some non-dumped entries. To improve this, we could attach a 'sernum' attribute (similar to the one used for IPv6) to nexthop entities, and bump this counter whenever exceptions change: having a distinction between the two counters would make this more convenient. Listing of exception routes (modified routes pre-3.5) was tested against these versions of kernel and iproute2: iproute2 kernel 4.14.0 4.15.0 4.19.0 5.0.0 5.1.0 3.5-rc4 + + + + + 4.4 4.9 4.14 4.15 4.19 5.0 5.1 fixed + + + + + v7: - Move loop over nexthop objects to route.c, and pass struct fib_info and table ID to it, not a struct fib_alias (suggested by David Ahern) - While at it, note that the NULL check on fa->fa_info is redundant, and the check on RTNH_F_DEAD is also not consistent with what's done with regular route listing: just keep it for nhc_flags - Rename entry point function for dumping exceptions to fib_dump_info_fnhe(), and rearrange arguments for consistency with fib_dump_info() - Rename fnhe_dump_buckets() to fnhe_dump_bucket() and make it handle one bucket at a time - Expand commit message to describe why we can have a single "skip" counter for all exceptions stored in bucket chains in nexthop objects (suggested by David Ahern) v6: - Rebased onto net-next - Loop over nexthop paths too. Move loop over fnhe buckets to route.c, avoids need to export rt_fill_info() and to touch exceptions from fib_trie.c. Pass NULL as flow to rt_fill_info(), it now allows that (suggested by David Ahern) Fixes:4895c771c7("ipv4: Add FIB nexthop exceptions.") Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
386 lines
11 KiB
C
386 lines
11 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Definitions for the IP router.
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*
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* Version: @(#)route.h 1.0.4 05/27/93
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*
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* Authors: Ross Biro
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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* Fixes:
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* Alan Cox : Reformatted. Added ip_rt_local()
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* Alan Cox : Support for TCP parameters.
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* Alexey Kuznetsov: Major changes for new routing code.
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* Mike McLagan : Routing by source
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* Robert Olsson : Added rt_cache statistics
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*/
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#ifndef _ROUTE_H
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#define _ROUTE_H
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#include <net/dst.h>
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#include <net/inetpeer.h>
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#include <net/flow.h>
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#include <net/inet_sock.h>
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#include <net/ip_fib.h>
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#include <net/arp.h>
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#include <net/ndisc.h>
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#include <linux/in_route.h>
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#include <linux/rtnetlink.h>
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#include <linux/rcupdate.h>
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#include <linux/route.h>
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#include <linux/ip.h>
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#include <linux/cache.h>
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#include <linux/security.h>
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/* IPv4 datagram length is stored into 16bit field (tot_len) */
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#define IP_MAX_MTU 0xFFFFU
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#define RTO_ONLINK 0x01
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#define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
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#define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
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struct fib_nh;
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struct fib_info;
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struct uncached_list;
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struct rtable {
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struct dst_entry dst;
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int rt_genid;
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unsigned int rt_flags;
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__u16 rt_type;
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__u8 rt_is_input;
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u8 rt_gw_family;
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int rt_iif;
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/* Info on neighbour */
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union {
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__be32 rt_gw4;
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struct in6_addr rt_gw6;
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};
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/* Miscellaneous cached information */
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u32 rt_mtu_locked:1,
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rt_pmtu:31;
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struct list_head rt_uncached;
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struct uncached_list *rt_uncached_list;
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};
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static inline bool rt_is_input_route(const struct rtable *rt)
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{
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return rt->rt_is_input != 0;
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}
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static inline bool rt_is_output_route(const struct rtable *rt)
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{
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return rt->rt_is_input == 0;
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}
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static inline __be32 rt_nexthop(const struct rtable *rt, __be32 daddr)
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{
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if (rt->rt_gw_family == AF_INET)
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return rt->rt_gw4;
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return daddr;
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}
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struct ip_rt_acct {
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__u32 o_bytes;
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__u32 o_packets;
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__u32 i_bytes;
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__u32 i_packets;
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};
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struct rt_cache_stat {
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unsigned int in_slow_tot;
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unsigned int in_slow_mc;
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unsigned int in_no_route;
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unsigned int in_brd;
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unsigned int in_martian_dst;
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unsigned int in_martian_src;
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unsigned int out_slow_tot;
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unsigned int out_slow_mc;
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};
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extern struct ip_rt_acct __percpu *ip_rt_acct;
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struct in_device;
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int ip_rt_init(void);
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void rt_cache_flush(struct net *net);
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void rt_flush_dev(struct net_device *dev);
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struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *flp,
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const struct sk_buff *skb);
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struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *flp,
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struct fib_result *res,
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const struct sk_buff *skb);
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static inline struct rtable *__ip_route_output_key(struct net *net,
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struct flowi4 *flp)
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{
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return ip_route_output_key_hash(net, flp, NULL);
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}
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struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
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const struct sock *sk);
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struct dst_entry *ipv4_blackhole_route(struct net *net,
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struct dst_entry *dst_orig);
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static inline struct rtable *ip_route_output_key(struct net *net, struct flowi4 *flp)
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{
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return ip_route_output_flow(net, flp, NULL);
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}
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static inline struct rtable *ip_route_output(struct net *net, __be32 daddr,
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__be32 saddr, u8 tos, int oif)
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{
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struct flowi4 fl4 = {
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.flowi4_oif = oif,
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.flowi4_tos = tos,
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.daddr = daddr,
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.saddr = saddr,
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};
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return ip_route_output_key(net, &fl4);
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}
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static inline struct rtable *ip_route_output_ports(struct net *net, struct flowi4 *fl4,
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struct sock *sk,
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__be32 daddr, __be32 saddr,
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__be16 dport, __be16 sport,
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__u8 proto, __u8 tos, int oif)
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{
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flowi4_init_output(fl4, oif, sk ? sk->sk_mark : 0, tos,
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RT_SCOPE_UNIVERSE, proto,
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sk ? inet_sk_flowi_flags(sk) : 0,
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daddr, saddr, dport, sport, sock_net_uid(net, sk));
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if (sk)
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security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
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return ip_route_output_flow(net, fl4, sk);
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}
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static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 *fl4,
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__be32 daddr, __be32 saddr,
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__be32 gre_key, __u8 tos, int oif)
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{
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memset(fl4, 0, sizeof(*fl4));
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fl4->flowi4_oif = oif;
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fl4->daddr = daddr;
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fl4->saddr = saddr;
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fl4->flowi4_tos = tos;
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fl4->flowi4_proto = IPPROTO_GRE;
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fl4->fl4_gre_key = gre_key;
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return ip_route_output_key(net, fl4);
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}
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int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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u8 tos, struct net_device *dev,
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struct in_device *in_dev, u32 *itag);
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int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,
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u8 tos, struct net_device *devin);
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int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,
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u8 tos, struct net_device *devin,
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struct fib_result *res);
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static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
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u8 tos, struct net_device *devin)
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{
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int err;
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rcu_read_lock();
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err = ip_route_input_noref(skb, dst, src, tos, devin);
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if (!err) {
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skb_dst_force(skb);
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if (!skb_dst(skb))
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err = -EINVAL;
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}
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rcu_read_unlock();
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return err;
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}
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void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,
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u8 protocol);
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void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
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void ipv4_redirect(struct sk_buff *skb, struct net *net, int oif, u8 protocol);
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void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk);
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void ip_rt_send_redirect(struct sk_buff *skb);
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unsigned int inet_addr_type(struct net *net, __be32 addr);
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unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id);
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unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
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__be32 addr);
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unsigned int inet_addr_type_dev_table(struct net *net,
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const struct net_device *dev,
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__be32 addr);
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void ip_rt_multicast_event(struct in_device *);
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int ip_rt_ioctl(struct net *, unsigned int cmd, struct rtentry *rt);
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void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
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struct rtable *rt_dst_alloc(struct net_device *dev,
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unsigned int flags, u16 type,
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bool nopolicy, bool noxfrm, bool will_cache);
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struct in_ifaddr;
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void fib_add_ifaddr(struct in_ifaddr *);
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void fib_del_ifaddr(struct in_ifaddr *, struct in_ifaddr *);
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void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric);
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void rt_add_uncached_list(struct rtable *rt);
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void rt_del_uncached_list(struct rtable *rt);
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int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
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u32 table_id, struct fib_info *fi,
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int *fa_index, int fa_start);
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static inline void ip_rt_put(struct rtable *rt)
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{
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/* dst_release() accepts a NULL parameter.
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* We rely on dst being first structure in struct rtable
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*/
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BUILD_BUG_ON(offsetof(struct rtable, dst) != 0);
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dst_release(&rt->dst);
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}
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#define IPTOS_RT_MASK (IPTOS_TOS_MASK & ~3)
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extern const __u8 ip_tos2prio[16];
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static inline char rt_tos2priority(u8 tos)
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{
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return ip_tos2prio[IPTOS_TOS(tos)>>1];
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}
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/* ip_route_connect() and ip_route_newports() work in tandem whilst
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* binding a socket for a new outgoing connection.
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*
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* In order to use IPSEC properly, we must, in the end, have a
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* route that was looked up using all available keys including source
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* and destination ports.
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*
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* However, if a source port needs to be allocated (the user specified
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* a wildcard source port) we need to obtain addressing information
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* in order to perform that allocation.
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*
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* So ip_route_connect() looks up a route using wildcarded source and
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* destination ports in the key, simply so that we can get a pair of
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* addresses to use for port allocation.
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*
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* Later, once the ports are allocated, ip_route_newports() will make
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* another route lookup if needed to make sure we catch any IPSEC
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* rules keyed on the port information.
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*
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* The callers allocate the flow key on their stack, and must pass in
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* the same flowi4 object to both the ip_route_connect() and the
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* ip_route_newports() calls.
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*/
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static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
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u32 tos, int oif, u8 protocol,
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__be16 sport, __be16 dport,
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struct sock *sk)
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{
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__u8 flow_flags = 0;
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if (inet_sk(sk)->transparent)
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flow_flags |= FLOWI_FLAG_ANYSRC;
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flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
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protocol, flow_flags, dst, src, dport, sport,
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sk->sk_uid);
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}
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static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
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__be32 dst, __be32 src, u32 tos,
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int oif, u8 protocol,
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__be16 sport, __be16 dport,
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struct sock *sk)
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{
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struct net *net = sock_net(sk);
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struct rtable *rt;
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ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
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sport, dport, sk);
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if (!dst || !src) {
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rt = __ip_route_output_key(net, fl4);
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if (IS_ERR(rt))
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return rt;
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ip_rt_put(rt);
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flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
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}
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security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
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return ip_route_output_flow(net, fl4, sk);
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}
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static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable *rt,
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__be16 orig_sport, __be16 orig_dport,
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__be16 sport, __be16 dport,
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struct sock *sk)
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{
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if (sport != orig_sport || dport != orig_dport) {
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fl4->fl4_dport = dport;
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fl4->fl4_sport = sport;
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ip_rt_put(rt);
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flowi4_update_output(fl4, sk->sk_bound_dev_if,
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RT_CONN_FLAGS(sk), fl4->daddr,
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fl4->saddr);
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security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
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return ip_route_output_flow(sock_net(sk), fl4, sk);
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}
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return rt;
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}
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static inline int inet_iif(const struct sk_buff *skb)
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{
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struct rtable *rt = skb_rtable(skb);
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if (rt && rt->rt_iif)
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return rt->rt_iif;
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return skb->skb_iif;
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}
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static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
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{
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int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
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struct net *net = dev_net(dst->dev);
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if (hoplimit == 0)
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hoplimit = net->ipv4.sysctl_ip_default_ttl;
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return hoplimit;
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}
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static inline struct neighbour *ip_neigh_gw4(struct net_device *dev,
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__be32 daddr)
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{
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struct neighbour *neigh;
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neigh = __ipv4_neigh_lookup_noref(dev, daddr);
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if (unlikely(!neigh))
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neigh = __neigh_create(&arp_tbl, &daddr, dev, false);
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return neigh;
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}
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static inline struct neighbour *ip_neigh_for_gw(struct rtable *rt,
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struct sk_buff *skb,
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bool *is_v6gw)
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{
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struct net_device *dev = rt->dst.dev;
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struct neighbour *neigh;
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if (likely(rt->rt_gw_family == AF_INET)) {
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neigh = ip_neigh_gw4(dev, rt->rt_gw4);
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} else if (rt->rt_gw_family == AF_INET6) {
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neigh = ip_neigh_gw6(dev, &rt->rt_gw6);
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*is_v6gw = true;
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} else {
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neigh = ip_neigh_gw4(dev, ip_hdr(skb)->daddr);
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}
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return neigh;
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}
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#endif /* _ROUTE_H */
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