| Message ID | 20210704190252.11866-8-xiyou.wangcong@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | BPF |
| Headers | show |
| Series | sockmap: add sockmap support for unix datagram socket | expand |
On 7/4/21 9:02 PM, Cong Wang wrote: > From: Cong Wang <cong.wang@bytedance.com> > > We have to implement unix_dgram_bpf_recvmsg() to replace the > original ->recvmsg() to retrieve skmsg from ingress_msg. > > AF_UNIX is again special here because the lack of > sk_prot->recvmsg(). I simply add a special case inside > unix_dgram_recvmsg() to call sk->sk_prot->recvmsg() directly. > > Cc: John Fastabend <john.fastabend@gmail.com> > Cc: Daniel Borkmann <daniel@iogearbox.net> > Cc: Jakub Sitnicki <jakub@cloudflare.com> > Cc: Lorenz Bauer <lmb@cloudflare.com> > Signed-off-by: Cong Wang <cong.wang@bytedance.com> > --- > include/net/af_unix.h | 2 ++ > net/unix/af_unix.c | 19 +++++++++-- > net/unix/unix_bpf.c | 75 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 93 insertions(+), 3 deletions(-) > > diff --git a/include/net/af_unix.h b/include/net/af_unix.h > index cca645846af1..435a2c3d5a6f 100644 > --- a/include/net/af_unix.h > +++ b/include/net/af_unix.h > @@ -82,6 +82,8 @@ static inline struct unix_sock *unix_sk(const struct sock *sk) > long unix_inq_len(struct sock *sk); > long unix_outq_len(struct sock *sk); > > +int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, > + int flags); > #ifdef CONFIG_SYSCTL > int unix_sysctl_register(struct net *net); > void unix_sysctl_unregister(struct net *net); > diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c > index 573253c5b5c2..89927678c0dc 100644 > --- a/net/unix/af_unix.c > +++ b/net/unix/af_unix.c > @@ -2098,11 +2098,11 @@ static void unix_copy_addr(struct msghdr *msg, struct sock *sk) > } > } > > -static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, > - size_t size, int flags) > +int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, > + int flags) > { > struct scm_cookie scm; > - struct sock *sk = sock->sk; > + struct socket *sock = sk->sk_socket; > struct unix_sock *u = unix_sk(sk); > struct sk_buff *skb, *last; > long timeo; > @@ -2205,6 +2205,19 @@ static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, > return err; > } > > +static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, > + int flags) > +{ > + struct sock *sk = sock->sk; > + > +#ifdef CONFIG_BPF_SYSCALL > + if (sk->sk_prot != &unix_proto) > + return sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT, > + flags & ~MSG_DONTWAIT, NULL); > +#endif > + return __unix_dgram_recvmsg(sk, msg, size, flags); > +} > + > static int unix_read_sock(struct sock *sk, read_descriptor_t *desc, > sk_read_actor_t recv_actor) > { > diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c > index b1582a659427..db0cda29fb2f 100644 > --- a/net/unix/unix_bpf.c > +++ b/net/unix/unix_bpf.c > @@ -6,6 +6,80 @@ > #include <net/sock.h> > #include <net/af_unix.h> > > +#define unix_sk_has_data(__sk, __psock) \ > + ({ !skb_queue_empty(&__sk->sk_receive_queue) || \ > + !skb_queue_empty(&__psock->ingress_skb) || \ > + !list_empty(&__psock->ingress_msg); \ > + }) > + > +static int unix_msg_wait_data(struct sock *sk, struct sk_psock *psock, > + long timeo) > +{ > + DEFINE_WAIT_FUNC(wait, woken_wake_function); > + struct unix_sock *u = unix_sk(sk); > + int ret = 0; > + > + if (sk->sk_shutdown & RCV_SHUTDOWN) > + return 1; > + > + if (!timeo) > + return ret; > + > + add_wait_queue(sk_sleep(sk), &wait); > + sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); > + if (!unix_sk_has_data(sk, psock)) { > + mutex_unlock(&u->iolock); > + wait_woken(&wait, TASK_INTERRUPTIBLE, timeo); > + mutex_lock(&u->iolock); > + ret = unix_sk_has_data(sk, psock); > + } > + sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); > + remove_wait_queue(sk_sleep(sk), &wait); > + return ret; > +} > + > +static int unix_dgram_bpf_recvmsg(struct sock *sk, struct msghdr *msg, > + size_t len, int nonblock, int flags, > + int *addr_len) > +{ > + struct unix_sock *u = unix_sk(sk); > + struct sk_psock *psock; > + int copied, ret; > + > + psock = sk_psock_get(sk); > + if (unlikely(!psock)) > + return __unix_dgram_recvmsg(sk, msg, len, flags); > + > + mutex_lock(&u->iolock); u->iolock mutex is owned here. > + if (!skb_queue_empty(&sk->sk_receive_queue) && > + sk_psock_queue_empty(psock)) { > + ret = __unix_dgram_recvmsg(sk, msg, len, flags); But __unix_dgram_recvmsg() will also try to grab this mutex ? > + goto out; > + } > + > +msg_bytes_ready: > + copied = sk_msg_recvmsg(sk, psock, msg, len, flags); > + if (!copied) { > + long timeo; > + int data; > + > + timeo = sock_rcvtimeo(sk, nonblock); > + data = unix_msg_wait_data(sk, psock, timeo); > + if (data) { > + if (!sk_psock_queue_empty(psock)) > + goto msg_bytes_ready; > + ret = __unix_dgram_recvmsg(sk, msg, len, flags); > + goto out; > + } > + copied = -EAGAIN; > + } > + ret = copied; > +out: > + mutex_unlock(&u->iolock); > + sk_psock_put(sk, psock); > + return ret; > +} > + > static struct proto *unix_prot_saved __read_mostly; > static DEFINE_SPINLOCK(unix_prot_lock); > static struct proto unix_bpf_prot; > @@ -14,6 +88,7 @@ static void unix_bpf_rebuild_protos(struct proto *prot, const struct proto *base > { > *prot = *base; > prot->close = sock_map_close; > + prot->recvmsg = unix_dgram_bpf_recvmsg; > } > > static void unix_bpf_check_needs_rebuild(struct proto *ops) >
On Sun, Jul 18, 2021 at 10:49 AM Eric Dumazet <eric.dumazet@gmail.com> wrote: > > > > On 7/4/21 9:02 PM, Cong Wang wrote: > > From: Cong Wang <cong.wang@bytedance.com> > > + mutex_lock(&u->iolock); > > u->iolock mutex is owned here. > > > + if (!skb_queue_empty(&sk->sk_receive_queue) && > > + sk_psock_queue_empty(psock)) { > > + ret = __unix_dgram_recvmsg(sk, msg, len, flags); > > But __unix_dgram_recvmsg() will also try to grab this mutex ? Good catch. I should release the lock before calling it. I will send a patch. Thanks.
diff --git a/include/net/af_unix.h b/include/net/af_unix.h index cca645846af1..435a2c3d5a6f 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -82,6 +82,8 @@ static inline struct unix_sock *unix_sk(const struct sock *sk) long unix_inq_len(struct sock *sk); long unix_outq_len(struct sock *sk); +int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, + int flags); #ifdef CONFIG_SYSCTL int unix_sysctl_register(struct net *net); void unix_sysctl_unregister(struct net *net); diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 573253c5b5c2..89927678c0dc 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2098,11 +2098,11 @@ static void unix_copy_addr(struct msghdr *msg, struct sock *sk) } } -static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, - size_t size, int flags) +int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, + int flags) { struct scm_cookie scm; - struct sock *sk = sock->sk; + struct socket *sock = sk->sk_socket; struct unix_sock *u = unix_sk(sk); struct sk_buff *skb, *last; long timeo; @@ -2205,6 +2205,19 @@ static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, return err; } +static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, + int flags) +{ + struct sock *sk = sock->sk; + +#ifdef CONFIG_BPF_SYSCALL + if (sk->sk_prot != &unix_proto) + return sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT, + flags & ~MSG_DONTWAIT, NULL); +#endif + return __unix_dgram_recvmsg(sk, msg, size, flags); +} + static int unix_read_sock(struct sock *sk, read_descriptor_t *desc, sk_read_actor_t recv_actor) { diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c index b1582a659427..db0cda29fb2f 100644 --- a/net/unix/unix_bpf.c +++ b/net/unix/unix_bpf.c @@ -6,6 +6,80 @@ #include <net/sock.h> #include <net/af_unix.h> +#define unix_sk_has_data(__sk, __psock) \ + ({ !skb_queue_empty(&__sk->sk_receive_queue) || \ + !skb_queue_empty(&__psock->ingress_skb) || \ + !list_empty(&__psock->ingress_msg); \ + }) + +static int unix_msg_wait_data(struct sock *sk, struct sk_psock *psock, + long timeo) +{ + DEFINE_WAIT_FUNC(wait, woken_wake_function); + struct unix_sock *u = unix_sk(sk); + int ret = 0; + + if (sk->sk_shutdown & RCV_SHUTDOWN) + return 1; + + if (!timeo) + return ret; + + add_wait_queue(sk_sleep(sk), &wait); + sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); + if (!unix_sk_has_data(sk, psock)) { + mutex_unlock(&u->iolock); + wait_woken(&wait, TASK_INTERRUPTIBLE, timeo); + mutex_lock(&u->iolock); + ret = unix_sk_has_data(sk, psock); + } + sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); + remove_wait_queue(sk_sleep(sk), &wait); + return ret; +} + +static int unix_dgram_bpf_recvmsg(struct sock *sk, struct msghdr *msg, + size_t len, int nonblock, int flags, + int *addr_len) +{ + struct unix_sock *u = unix_sk(sk); + struct sk_psock *psock; + int copied, ret; + + psock = sk_psock_get(sk); + if (unlikely(!psock)) + return __unix_dgram_recvmsg(sk, msg, len, flags); + + mutex_lock(&u->iolock); + if (!skb_queue_empty(&sk->sk_receive_queue) && + sk_psock_queue_empty(psock)) { + ret = __unix_dgram_recvmsg(sk, msg, len, flags); + goto out; + } + +msg_bytes_ready: + copied = sk_msg_recvmsg(sk, psock, msg, len, flags); + if (!copied) { + long timeo; + int data; + + timeo = sock_rcvtimeo(sk, nonblock); + data = unix_msg_wait_data(sk, psock, timeo); + if (data) { + if (!sk_psock_queue_empty(psock)) + goto msg_bytes_ready; + ret = __unix_dgram_recvmsg(sk, msg, len, flags); + goto out; + } + copied = -EAGAIN; + } + ret = copied; +out: + mutex_unlock(&u->iolock); + sk_psock_put(sk, psock); + return ret; +} + static struct proto *unix_prot_saved __read_mostly; static DEFINE_SPINLOCK(unix_prot_lock); static struct proto unix_bpf_prot; @@ -14,6 +88,7 @@ static void unix_bpf_rebuild_protos(struct proto *prot, const struct proto *base { *prot = *base; prot->close = sock_map_close; + prot->recvmsg = unix_dgram_bpf_recvmsg; } static void unix_bpf_check_needs_rebuild(struct proto *ops)