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Date: Mon, 1 Mar 2021 18:37:36 -0800
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: bpf@...r.kernel.org, duanxiongchun@...edance.com,
wangdongdong.6@...edance.com, jiang.wang@...edance.com,
Cong Wang <cong.wang@...edance.com>,
John Fastabend <john.fastabend@...il.com>,
Daniel Borkmann <daniel@...earbox.net>,
Jakub Sitnicki <jakub@...udflare.com>,
Lorenz Bauer <lmb@...udflare.com>
Subject: [Patch bpf-next v2 2/9] sock: introduce sk_prot->update_proto()
From: Cong Wang <cong.wang@...edance.com>
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->update_proto(), so each protocol
can implement its own way to replace the struct proto. This also
helps get rid of symbol dependencies on CONFIG_INET.
Cc: John Fastabend <john.fastabend@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Jakub Sitnicki <jakub@...udflare.com>
Cc: Lorenz Bauer <lmb@...udflare.com>
Signed-off-by: Cong Wang <cong.wang@...edance.com>
---
include/linux/skmsg.h | 18 +++---------------
include/net/sock.h | 3 +++
include/net/tcp.h | 1 +
include/net/udp.h | 1 +
net/core/skmsg.c | 5 -----
net/core/sock_map.c | 24 ++++--------------------
net/ipv4/tcp_bpf.c | 23 ++++++++++++++++++++---
net/ipv4/tcp_ipv4.c | 3 +++
net/ipv4/udp.c | 3 +++
net/ipv4/udp_bpf.c | 14 ++++++++++++--
net/ipv6/tcp_ipv6.c | 3 +++
net/ipv6/udp.c | 3 +++
12 files changed, 56 insertions(+), 45 deletions(-)
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 451530d41af7..b5df69d5d397 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -98,6 +98,7 @@ struct sk_psock {
void (*saved_close)(struct sock *sk, long timeout);
void (*saved_write_space)(struct sock *sk);
void (*saved_data_ready)(struct sock *sk);
+ int (*saved_update_proto)(struct sock *sk, bool restore);
struct proto *sk_proto;
struct sk_psock_work_state work_state;
struct work_struct work;
@@ -350,25 +351,12 @@ static inline void sk_psock_cork_free(struct sk_psock *psock)
}
}
-static inline void sk_psock_update_proto(struct sock *sk,
- struct sk_psock *psock,
- struct proto *ops)
-{
- /* Pairs with lockless read in sk_clone_lock() */
- WRITE_ONCE(sk->sk_prot, ops);
-}
-
static inline void sk_psock_restore_proto(struct sock *sk,
struct sk_psock *psock)
{
sk->sk_prot->unhash = psock->saved_unhash;
- 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);
- }
+ if (psock->saved_update_proto)
+ psock->saved_update_proto(sk, true);
}
static inline void sk_psock_set_state(struct sk_psock *psock,
diff --git a/include/net/sock.h b/include/net/sock.h
index 636810ddcd9b..0e8577c917e8 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1184,6 +1184,9 @@ struct proto {
void (*unhash)(struct sock *sk);
void (*rehash)(struct sock *sk);
int (*get_port)(struct sock *sk, unsigned short snum);
+#ifdef CONFIG_BPF_SYSCALL
+ int (*update_proto)(struct sock *sk, bool restore);
+#endif
/* Keeping track of sockets in use */
#ifdef CONFIG_PROC_FS
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 075de26f449d..2efa4e5ea23d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2203,6 +2203,7 @@ struct sk_psock;
#ifdef CONFIG_BPF_SYSCALL
struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
+int tcp_bpf_update_proto(struct sock *sk, bool restore);
void tcp_bpf_clone(const struct sock *sk, struct sock *newsk);
#endif /* CONFIG_BPF_SYSCALL */
diff --git a/include/net/udp.h b/include/net/udp.h
index d4d064c59232..df7cc1edc200 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -518,6 +518,7 @@ static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
#ifdef CONFIG_BPF_SYSCALL
struct sk_psock;
struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock);
+int udp_bpf_update_proto(struct sock *sk, bool restore);
#endif
#endif /* _UDP_H */
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 5efd790f1b47..7dbd8344ec89 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -563,11 +563,6 @@ struct sk_psock *sk_psock_init(struct sock *sk, int node)
write_lock_bh(&sk->sk_callback_lock);
- if (inet_csk_has_ulp(sk)) {
- psock = ERR_PTR(-EINVAL);
- goto out;
- }
-
if (sk->sk_user_data) {
psock = ERR_PTR(-EBUSY);
goto out;
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 3bddd9dd2da2..13d2af5bb81c 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -184,26 +184,10 @@ static void sock_map_unref(struct sock *sk, void *link_raw)
static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
{
- struct proto *prot;
-
- switch (sk->sk_type) {
- case SOCK_STREAM:
- prot = tcp_bpf_get_proto(sk, psock);
- break;
-
- case SOCK_DGRAM:
- prot = udp_bpf_get_proto(sk, psock);
- break;
-
- default:
+ if (!sk->sk_prot->update_proto)
return -EINVAL;
- }
-
- if (IS_ERR(prot))
- return PTR_ERR(prot);
-
- sk_psock_update_proto(sk, psock, prot);
- return 0;
+ psock->saved_update_proto = sk->sk_prot->update_proto;
+ return sk->sk_prot->update_proto(sk, false);
}
static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
@@ -570,7 +554,7 @@ static bool sock_map_redirect_allowed(const struct sock *sk)
static bool sock_map_sk_is_suitable(const struct sock *sk)
{
- return sk_is_tcp(sk) || sk_is_udp(sk);
+ return !!sk->sk_prot->update_proto;
}
static bool sock_map_sk_state_allowed(const struct sock *sk)
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 17c322b875fd..737726c8138c 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -601,19 +601,36 @@ 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;
}
/* If a child got cloned from a listening socket that had tcp_bpf
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index daad4f99db32..21c9e262d07c 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
+ .update_proto = 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..dbd25b59ce0e 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
+ .update_proto = 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..595836088e85 100644
--- a/net/ipv4/udp_bpf.c
+++ b/net/ipv4/udp_bpf.c
@@ -41,12 +41,22 @@ 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;
}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index bd44ded7e50c..ea5be7e7fcb8 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2134,6 +2134,9 @@ struct proto tcpv6_prot = {
.hash = inet6_hash,
.unhash = inet_unhash,
.get_port = inet_csk_get_port,
+#ifdef CONFIG_BPF_SYSCALL
+ .update_proto = 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/ipv6/udp.c b/net/ipv6/udp.c
index d25e5a9252fd..105ba0cf739d 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1713,6 +1713,9 @@ struct proto udpv6_prot = {
.unhash = udp_lib_unhash,
.rehash = udp_v6_rehash,
.get_port = udp_v6_get_port,
+#ifdef CONFIG_BPF_SYSCALL
+ .update_proto = 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),
--
2.25.1
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