af_unix: Add read_sock for stream socket types

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>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210816190327.2739291-2-jiang.wang@bytedance.com

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index bad8f19..4455b62 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -679,6 +679,8 @@ 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);
@@ -732,6 +734,7 @@ 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,
@@ -2491,6 +2494,15 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 }
 #endif
 
+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)
 {