From 8a59f9d1e3d4340659fdfee8879dc09a6f2546e1 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Tue, 30 Mar 2021 19:32:31 -0700 Subject: sock: Introduce sk->sk_prot->psock_update_sk_prot() 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 Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210331023237.41094-11-xiyou.wangcong@gmail.com --- net/ipv4/tcp_bpf.c | 24 +++++++++++++++++++++--- net/ipv4/tcp_ipv4.c | 3 +++ net/ipv4/udp.c | 3 +++ net/ipv4/udp_bpf.c | 15 +++++++++++++-- 4 files changed, 40 insertions(+), 5 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index ae980716d896..ac8cfbaeacd2 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -595,20 +595,38 @@ static int tcp_bpf_assert_proto_ops(struct proto *ops) ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; } -struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock) +int tcp_bpf_update_proto(struct sock *sk, bool restore) { + struct sk_psock *psock = sk_psock(sk); int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; + if (restore) { + if (inet_csk_has_ulp(sk)) { + tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space); + } else { + 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; + } + + if (inet_csk_has_ulp(sk)) + return -EINVAL; + if (sk->sk_family == AF_INET6) { if (tcp_bpf_assert_proto_ops(psock->sk_proto)) - return ERR_PTR(-EINVAL); + return -EINVAL; tcp_bpf_check_v6_needs_rebuild(psock->sk_proto); } - return &tcp_bpf_prots[family][config]; + /* Pairs with lockless read in sk_clone_lock() */ + WRITE_ONCE(sk->sk_prot, &tcp_bpf_prots[family][config]); + return 0; } +EXPORT_SYMBOL_GPL(tcp_bpf_update_proto); /* If a child got cloned from a listening socket that had tcp_bpf * protocol callbacks installed, we need to restore the callbacks to diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index daad4f99db32..dfc6d1c0e710 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2806,6 +2806,9 @@ struct proto tcp_prot = { .hash = inet_hash, .unhash = inet_unhash, .get_port = inet_csk_get_port, +#ifdef CONFIG_BPF_SYSCALL + .psock_update_sk_prot = tcp_bpf_update_proto, +#endif .enter_memory_pressure = tcp_enter_memory_pressure, .leave_memory_pressure = tcp_leave_memory_pressure, .stream_memory_free = tcp_stream_memory_free, diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 4a0478b17243..38952aaee3a1 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2849,6 +2849,9 @@ struct proto udp_prot = { .unhash = udp_lib_unhash, .rehash = udp_v4_rehash, .get_port = udp_v4_get_port, +#ifdef CONFIG_BPF_SYSCALL + .psock_update_sk_prot = udp_bpf_update_proto, +#endif .memory_allocated = &udp_memory_allocated, .sysctl_mem = sysctl_udp_mem, .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min), diff --git a/net/ipv4/udp_bpf.c b/net/ipv4/udp_bpf.c index 7a94791efc1a..6001f93cd3a0 100644 --- a/net/ipv4/udp_bpf.c +++ b/net/ipv4/udp_bpf.c @@ -41,12 +41,23 @@ static int __init udp_bpf_v4_build_proto(void) } core_initcall(udp_bpf_v4_build_proto); -struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock) +int udp_bpf_update_proto(struct sock *sk, bool restore) { int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6; + 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; + } if (sk->sk_family == AF_INET6) udp_bpf_check_v6_needs_rebuild(psock->sk_proto); - return &udp_bpf_prots[family]; + /* Pairs with lockless read in sk_clone_lock() */ + WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]); + return 0; } +EXPORT_SYMBOL_GPL(udp_bpf_update_proto); -- cgit v1.2.3-70-g09d2