diff --git a/include/net/af_unix.h b/include/net/af_unix.h index f42fdddecd417d..fa75f899e88a3c 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -89,4 +89,14 @@ void unix_sysctl_unregister(struct net *net); static inline int unix_sysctl_register(struct net *net) { return 0; } static inline void unix_sysctl_unregister(struct net *net) {} #endif + +extern struct proto unix_proto; + +#ifdef CONFIG_BPF_SOCK_MAP +int unix_bpf_update_proto(struct sock *sk, bool restore); +void __init unix_bpf_build_proto(void); +#else +static inline void __init unix_bpf_build_proto(void) +{} +#endif #endif diff --git a/net/unix/Makefile b/net/unix/Makefile index 54e58cc4f94502..9f461c23a429f8 100644 --- a/net/unix/Makefile +++ b/net/unix/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_UNIX_DIAG) += unix_diag.o unix_diag-y := diag.o obj-$(CONFIG_UNIX_SCM) += scm.o +obj-$(CONFIG_BPF_SOCK_MAP) += unix_bpf.o diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 9315c4f4c27a09..4ce12d3c369e48 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -773,10 +773,18 @@ static const struct proto_ops unix_seqpacket_ops = { .show_fdinfo = unix_show_fdinfo, }; -static struct proto unix_proto = { +static void unix_close(struct sock *sk, long timeout) +{ +} + +struct proto unix_proto = { .name = "UNIX", .owner = THIS_MODULE, .obj_size = sizeof(struct unix_sock), + .close = unix_close, +#ifdef CONFIG_BPF_SOCK_MAP + .update_proto = unix_bpf_update_proto, +#endif }; static struct sock *unix_create1(struct net *net, struct socket *sock, int kern) @@ -861,6 +869,7 @@ static int unix_release(struct socket *sock) return 0; unix_release_sock(sk, 0); + sk->sk_prot->close(sk, 0); sock->sk = NULL; return 0; @@ -2973,6 +2982,7 @@ static int __init af_unix_init(void) sock_register(&unix_family_ops); register_pernet_subsys(&unix_net_ops); + unix_bpf_build_proto(); out: return rc; } diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c new file mode 100644 index 00000000000000..b4acb2e94ca5a5 --- /dev/null +++ b/net/unix/unix_bpf.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Bytedance Inc. */ + +#include +#include +#include + +static struct proto *unix_prot_saved __read_mostly; +static DEFINE_SPINLOCK(unix_prot_lock); +static struct proto unix_bpf_prot; + +static void unix_bpf_rebuild_protos(struct proto *prot, const struct proto *base) +{ + *prot = *base; + prot->close = sock_map_close; +} + +static void unix_bpf_check_needs_rebuild(struct proto *ops) +{ + if (unlikely(ops != smp_load_acquire(&unix_prot_saved))) { + spin_lock_bh(&unix_prot_lock); + if (likely(ops != unix_prot_saved)) { + unix_bpf_rebuild_protos(&unix_bpf_prot, ops); + smp_store_release(&unix_prot_saved, ops); + } + spin_unlock_bh(&unix_prot_lock); + } +} + +int unix_bpf_update_proto(struct sock *sk, bool restore) +{ + struct sk_psock *psock = sk_psock(sk); + + if (restore) { + sk->sk_write_space = psock->saved_write_space; + /* Pairs with lockless read in sk_clone_lock() */ + WRITE_ONCE(sk->sk_prot, psock->sk_proto); + return 0; + } + + unix_bpf_check_needs_rebuild(psock->sk_proto); + /* Pairs with lockless read in sk_clone_lock() */ + WRITE_ONCE(sk->sk_prot, &unix_bpf_prot); + return 0; +} + +void __init unix_bpf_build_proto(void) +{ + unix_bpf_rebuild_protos(&unix_bpf_prot, &unix_proto); +}