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 <sim@netnation.com>
Bisected-by: Simon Kirby <sim@netnation.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 94d683a..fd54c5f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1466,9 +1466,13 @@
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);