tcp: allow MSG_ZEROCOPY transmission also in CLOSE_WAIT state

TCP transmission with MSG_ZEROCOPY fails if the peer closes its end of
the connection and so transitions this socket to CLOSE_WAIT state.

Transmission in close wait state is acceptable. Other similar tests in
the stack (e.g., in FastOpen) accept both states. Relax this test, too.

Link: https://www.mail-archive.com/[email protected]/msg276886.html
Link: https://www.mail-archive.com/[email protected]/msg227390.html
Fixes: f214f915e7db ("tcp: enable MSG_ZEROCOPY")
Reported-by: Marek Majkowski <[email protected]>
Signed-off-by: Willem de Bruijn <[email protected]>
CC: Yuchung Cheng <[email protected]>
CC: Neal Cardwell <[email protected]>
CC: Soheil Hassas Yeganeh <[email protected]>
CC: Alexey Kodanev <[email protected]>
Acked-by: Soheil Hassas Yeganeh <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 27e2f6837062374baaea267a8788b9fd91db25ff..2079145a3b7c5f498af429c9a8289342e4421fca 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1186,7 +1186,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
        flags = msg->msg_flags;
 
        if (flags & MSG_ZEROCOPY && size && sock_flag(sk, SOCK_ZEROCOPY)) {
-               if (sk->sk_state != TCP_ESTABLISHED) {
+               if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
                        err = -EINVAL;
                        goto out_err;
                }