Commit a27fd7a8 authored Feb 27, 2018 by Soheil Hassas Yeganeh Committed by David S. Miller Feb 28, 2018

tcp: purge write queue upon RST

When the connection is reset, there is no point in
keeping the packets on the write queue until the connection
is closed.

RFC 793 (page 70) and RFC 793-bis (page 64) both suggest
purging the write queue upon RST:
https://tools.ietf.org/html/draft-ietf-tcpm-rfc793bis-07



Moreover, this is essential for a correct MSG_ZEROCOPY
implementation, because userspace cannot call close(fd)
before receiving zerocopy signals even when the connection
is reset.

Fixes: f214f915 ("tcp: enable MSG_ZEROCOPY")
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 55e84dd7

net/ipv4/tcp_input.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -3992,6 +3992,7 @@ void tcp_reset(struct sock *sk)
		/* This barrier is coupled with smp_rmb() in tcp_poll() */
		smp_wmb();

		tcp_write_queue_purge(sk);
		tcp_done(sk);

		if (!sock_flag(sk, SOCK_DEAD))

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