4.2-stable review patch. If anyone has any objections, please let me know.
------------------ From: Yuchung Cheng <ych...@google.com> [ Upstream commit 0e45f4da5981895e885dd72fe912a3f8e32bae73 ] Some middle-boxes black-hole the data after the Fast Open handshake (https://www.ietf.org/proceedings/94/slides/slides-94-tcpm-13.pdf). The exact reason is unknown. The work-around is to disable Fast Open temporarily after multiple recurring timeouts with few or no data delivered in the established state. Signed-off-by: Yuchung Cheng <ych...@google.com> Signed-off-by: Eric Dumazet <eduma...@google.com> Reported-by: Christoph Paasch <cpaa...@apple.com> Signed-off-by: David S. Miller <da...@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- net/ipv4/tcp_timer.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -176,6 +176,18 @@ static int tcp_write_timeout(struct sock syn_set = true; } else { if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) { + /* Some middle-boxes may black-hole Fast Open _after_ + * the handshake. Therefore we conservatively disable + * Fast Open on this path on recurring timeouts with + * few or zero bytes acked after Fast Open. + */ + if (tp->syn_data_acked && + tp->bytes_acked <= tp->rx_opt.mss_clamp) { + tcp_fastopen_cache_set(sk, 0, NULL, true, 0); + if (icsk->icsk_retransmits == sysctl_tcp_retries1) + NET_INC_STATS_BH(sock_net(sk), + LINUX_MIB_TCPFASTOPENACTIVEFAIL); + } /* Black hole detection */ tcp_mtu_probing(icsk, sk); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
