[Patch bpf-next v3 03/10] af_unix: implement ->psock_update_sk_prot()
From: Cong Wang <hidden>
Date: 2021-04-26 02:50:21
Also in:
bpf
Subsystem:
bpf [l7 framework] (sockmap), networking [general], networking [sockets], networking [unix sockets], the rest · Maintainers:
John Fastabend, Jakub Sitnicki, Jiayuan Chen, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Linus Torvalds
From: Cong Wang <redacted> unix_proto is special, it is very different from INET proto, which even does not have a ->close(). We have to add a dummy one to satisfy sockmap. And now we can implement unix_bpf_update_proto() to update sk_prot. Cc: John Fastabend <john.fastabend@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jakub Sitnicki <jakub@cloudflare.com> Cc: Lorenz Bauer <redacted> Signed-off-by: Cong Wang <redacted> --- MAINTAINERS | 1 + include/net/af_unix.h | 10 +++++++++ net/core/sock_map.c | 1 + net/unix/Makefile | 1 + net/unix/af_unix.c | 12 ++++++++++- net/unix/unix_bpf.c | 47 +++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 71 insertions(+), 1 deletion(-) create mode 100644 net/unix/unix_bpf.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 217c7470bfa9..02532e11da5b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS@@ -10000,6 +10000,7 @@ F: net/core/skmsg.c F: net/core/sock_map.c F: net/ipv4/tcp_bpf.c F: net/ipv4/udp_bpf.c +F: net/unix/unix_bpf.c LANTIQ / INTEL Ethernet drivers M: Hauke Mehrtens <hauke@hauke-m.de>
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..cca645846af1 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 + +#ifdef CONFIG_BPF_SYSCALL +extern struct proto unix_proto; + +int unix_bpf_update_proto(struct sock *sk, struct sk_psock *psock, 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/core/sock_map.c b/net/core/sock_map.c
index 6f1b82b8ad49..1107c9dcc969 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c@@ -1536,6 +1536,7 @@ void sock_map_close(struct sock *sk, long timeout) release_sock(sk); saved_close(sk, timeout); } +EXPORT_SYMBOL_GPL(sock_map_close); static int sock_map_iter_attach_target(struct bpf_prog *prog, union bpf_iter_link_info *linfo,
diff --git a/net/unix/Makefile b/net/unix/Makefile
index 54e58cc4f945..20491825b4d0 100644
--- a/net/unix/Makefile
+++ b/net/unix/Makefile@@ -7,6 +7,7 @@ obj-$(CONFIG_UNIX) += unix.o unix-y := af_unix.o garbage.o unix-$(CONFIG_SYSCTL) += sysctl_net_unix.o +unix-$(CONFIG_BPF_SYSCALL) += unix_bpf.o obj-$(CONFIG_UNIX_DIAG) += unix_diag.o unix_diag-y := diag.o
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index f4dc22db371d..8968ed44a89f 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c@@ -772,10 +772,18 @@ 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_SYSCALL + .psock_update_sk_prot = unix_bpf_update_proto, +#endif }; static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
@@ -859,6 +867,7 @@ static int unix_release(struct socket *sock) if (!sk) return 0; + sk->sk_prot->close(sk, 0); unix_release_sock(sk, 0); sock->sk = NULL;
@@ -2958,6 +2967,7 @@ 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 000000000000..b1582a659427
--- /dev/null
+++ b/net/unix/unix_bpf.c@@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Cong Wang <cong.wang@bytedance.com> */ + +#include <linux/skmsg.h> +#include <linux/bpf.h> +#include <net/sock.h> +#include <net/af_unix.h> + +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, struct sk_psock *psock, bool restore) +{ + if (restore) { + sk->sk_write_space = psock->saved_write_space; + WRITE_ONCE(sk->sk_prot, psock->sk_proto); + return 0; + } + + unix_bpf_check_needs_rebuild(psock->sk_proto); + 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); +}
--
2.25.1