From dfd25ffffc132c00070eed64200e8950da5d7e9d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 10 Mar 2012 09:20:21 +0000 Subject: tcp: fix syncookie regression commit ea4fc0d619 (ipv4: Don't use rt->rt_{src,dst} in ip_queue_xmit()) added a serious regression on synflood handling. Simon Kirby discovered a successful connection was delayed by 20 seconds before being responsive. In my tests, I discovered that xmit frames were lost, and needed ~4 retransmits and a socket dst rebuild before being really sent. In case of syncookie initiated connection, we use a different path to initialize the socket dst, and inet->cork.fl.u.ip4 is left cleared. As ip_queue_xmit() now depends on inet flow being setup, fix this by copying the temp flowi4 we use in cookie_v4_check(). Reported-by: Simon Kirby Bisected-by: Simon Kirby Signed-off-by: Eric Dumazet Tested-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'net/ipv4/tcp_ipv4.c') diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 94d683a61cb..fd54c5f8a25 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1466,9 +1466,13 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; newinet->inet_id = newtp->write_seq ^ jiffies; - if (!dst && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL) - goto put_and_exit; - + if (!dst) { + dst = inet_csk_route_child_sock(sk, newsk, req); + if (!dst) + goto put_and_exit; + } else { + /* syncookie case : see end of cookie_v4_check() */ + } sk_setup_caps(newsk, dst); tcp_mtup_init(newsk); -- cgit v1.2.3