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https://github.com/torvalds/linux
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c63829182c
Now we can implement unix_bpf_update_proto() to update sk_prot, especially prot->close(). Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210704190252.11866-7-xiyou.wangcong@gmail.com
48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Cong Wang <cong.wang@bytedance.com> */
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#include <linux/skmsg.h>
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#include <linux/bpf.h>
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#include <net/sock.h>
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#include <net/af_unix.h>
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static struct proto *unix_prot_saved __read_mostly;
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static DEFINE_SPINLOCK(unix_prot_lock);
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static struct proto unix_bpf_prot;
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static void unix_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->close = sock_map_close;
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}
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static void unix_bpf_check_needs_rebuild(struct proto *ops)
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{
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if (unlikely(ops != smp_load_acquire(&unix_prot_saved))) {
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spin_lock_bh(&unix_prot_lock);
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if (likely(ops != unix_prot_saved)) {
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unix_bpf_rebuild_protos(&unix_bpf_prot, ops);
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smp_store_release(&unix_prot_saved, ops);
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}
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spin_unlock_bh(&unix_prot_lock);
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}
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}
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int unix_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
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{
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if (restore) {
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sk->sk_write_space = psock->saved_write_space;
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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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unix_bpf_check_needs_rebuild(psock->sk_proto);
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WRITE_ONCE(sk->sk_prot, &unix_bpf_prot);
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return 0;
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}
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void __init unix_bpf_build_proto(void)
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{
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unix_bpf_rebuild_protos(&unix_bpf_prot, &unix_proto);
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}
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