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391145ba2a
BPF kfuncs are meant to be called from BPF programs. Accordingly, most
kfuncs are not called from anywhere in the kernel, which the
-Wmissing-prototypes warning is unhappy about. We've peppered
__diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are
defined in the codebase to suppress this warning.
This patch adds two macros meant to bound one or many kfunc definitions.
All existing kfunc definitions which use these __diag calls to suppress
-Wmissing-prototypes are migrated to use the newly-introduced macros.
A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the
__bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier
version of this patch [0] and another recent mailing list thread [1].
In the future we might need to ignore different warnings or do other
kfunc-specific things. This change will make it easier to make such
modifications for all kfunc defs.
[0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/
[1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
78 lines
2.2 KiB
C
78 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Unstable NAT Helpers for XDP and TC-BPF hook
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*
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* These are called from the XDP and SCHED_CLS BPF programs. Note that it is
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* allowed to break compatibility for these functions since the interface they
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* are exposed through to BPF programs is explicitly unstable.
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*/
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#include <linux/bpf.h>
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#include <linux/btf_ids.h>
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#include <net/netfilter/nf_conntrack_bpf.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/nf_nat.h>
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__bpf_kfunc_start_defs();
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/* bpf_ct_set_nat_info - Set source or destination nat address
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*
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* Set source or destination nat address of the newly allocated
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* nf_conn before insertion. This must be invoked for referenced
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* PTR_TO_BTF_ID to nf_conn___init.
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*
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* Parameters:
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* @nfct - Pointer to referenced nf_conn object, obtained using
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* bpf_xdp_ct_alloc or bpf_skb_ct_alloc.
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* @addr - Nat source/destination address
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* @port - Nat source/destination port. Non-positive values are
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* interpreted as select a random port.
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* @manip - NF_NAT_MANIP_SRC or NF_NAT_MANIP_DST
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*/
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__bpf_kfunc int bpf_ct_set_nat_info(struct nf_conn___init *nfct,
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union nf_inet_addr *addr, int port,
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enum nf_nat_manip_type manip)
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{
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struct nf_conn *ct = (struct nf_conn *)nfct;
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u16 proto = nf_ct_l3num(ct);
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struct nf_nat_range2 range;
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if (proto != NFPROTO_IPV4 && proto != NFPROTO_IPV6)
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return -EINVAL;
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memset(&range, 0, sizeof(struct nf_nat_range2));
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range.flags = NF_NAT_RANGE_MAP_IPS;
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range.min_addr = *addr;
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range.max_addr = range.min_addr;
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if (port > 0) {
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range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
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range.min_proto.all = cpu_to_be16(port);
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range.max_proto.all = range.min_proto.all;
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}
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return nf_nat_setup_info(ct, &range, manip) == NF_DROP ? -ENOMEM : 0;
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}
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__bpf_kfunc_end_defs();
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BTF_SET8_START(nf_nat_kfunc_set)
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BTF_ID_FLAGS(func, bpf_ct_set_nat_info, KF_TRUSTED_ARGS)
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BTF_SET8_END(nf_nat_kfunc_set)
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static const struct btf_kfunc_id_set nf_bpf_nat_kfunc_set = {
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.owner = THIS_MODULE,
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.set = &nf_nat_kfunc_set,
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};
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int register_nf_nat_bpf(void)
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{
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int ret;
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ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP,
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&nf_bpf_nat_kfunc_set);
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if (ret)
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return ret;
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return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
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&nf_bpf_nat_kfunc_set);
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}
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