[PATCH bpf-next v4 1/5] af_unix: add read_sock for stream socket types

[Jiang Wang <jiang.wang@bytedance.com>]

To support sockmap for af_unix stream type, implement
read_sock, which is similar to the read_sock for unix
dgram sockets.

Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
---
 net/unix/af_unix.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 256c4e31132e..c020ad0e8438 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -672,6 +672,8 @@ static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
 static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
 static int unix_read_sock(struct sock *sk, read_descriptor_t *desc,
 			  sk_read_actor_t recv_actor);
+static int unix_stream_read_sock(struct sock *sk, read_descriptor_t *desc,
+				 sk_read_actor_t recv_actor);
 static int unix_dgram_connect(struct socket *, struct sockaddr *,
 			      int, int);
 static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
@@ -725,6 +727,7 @@ static const struct proto_ops unix_stream_ops = {
 	.shutdown =	unix_shutdown,
 	.sendmsg =	unix_stream_sendmsg,
 	.recvmsg =	unix_stream_recvmsg,
+	.read_sock =	unix_stream_read_sock,
 	.mmap =		sock_no_mmap,
 	.sendpage =	unix_stream_sendpage,
 	.splice_read =	unix_stream_splice_read,
@@ -2358,6 +2361,15 @@ struct unix_stream_read_state {
 	unsigned int splice_flags;
 };
 
+static int unix_stream_read_sock(struct sock *sk, read_descriptor_t *desc,
+				 sk_read_actor_t recv_actor)
+{
+	if (unlikely(sk->sk_state != TCP_ESTABLISHED))
+		return -ENOTCONN;
+
+	return unix_read_sock(sk, desc, recv_actor);
+}
+
 static int unix_stream_read_generic(struct unix_stream_read_state *state,
 				    bool freezable)
 {
-- 
2.20.1