8a59f9d1e3
Currently sockmap calls into each protocol to update the struct proto and replace it. This certainly won't work when the protocol is implemented as a module, for example, AF_UNIX. Introduce a new ops sk->sk_prot->psock_update_sk_prot(), so each protocol can implement its own way to replace the struct proto. This also helps get rid of symbol dependencies on CONFIG_INET. Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210331023237.41094-11-xiyou.wangcong@gmail.com
64 lines
1.6 KiB
C
64 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Cloudflare Ltd https://cloudflare.com */
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#include <linux/skmsg.h>
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#include <net/sock.h>
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#include <net/udp.h>
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enum {
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UDP_BPF_IPV4,
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UDP_BPF_IPV6,
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UDP_BPF_NUM_PROTS,
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};
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static struct proto *udpv6_prot_saved __read_mostly;
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static DEFINE_SPINLOCK(udpv6_prot_lock);
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static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
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static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
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{
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*prot = *base;
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prot->unhash = sock_map_unhash;
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prot->close = sock_map_close;
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}
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static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
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{
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if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
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spin_lock_bh(&udpv6_prot_lock);
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if (likely(ops != udpv6_prot_saved)) {
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udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
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smp_store_release(&udpv6_prot_saved, ops);
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}
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spin_unlock_bh(&udpv6_prot_lock);
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}
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}
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static int __init udp_bpf_v4_build_proto(void)
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{
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udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
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return 0;
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}
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core_initcall(udp_bpf_v4_build_proto);
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int udp_bpf_update_proto(struct sock *sk, bool restore)
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{
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int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
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struct sk_psock *psock = sk_psock(sk);
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if (restore) {
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sk->sk_write_space = psock->saved_write_space;
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/* Pairs with lockless read in sk_clone_lock() */
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WRITE_ONCE(sk->sk_prot, psock->sk_proto);
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return 0;
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}
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if (sk->sk_family == AF_INET6)
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udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
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/* Pairs with lockless read in sk_clone_lock() */
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WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
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return 0;
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}
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EXPORT_SYMBOL_GPL(udp_bpf_update_proto);
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