From 93b174ad71b08e504c2cf6e8a58ecce778b77a40 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Thu, 6 Dec 2012 08:45:32 +0000 Subject: tcp: bug fix Fast Open client retransmission If SYN-ACK partially acks SYN-data, the client retransmits the remaining data by tcp_retransmit_skb(). This increments lost recovery state variables like tp->retrans_out in Open state. If loss recovery happens before the retransmission is acked, it triggers the WARN_ON check in tcp_fastretrans_alert(). For example: the client sends SYN-data, gets SYN-ACK acking only ISN, retransmits data, sends another 4 data packets and get 3 dupacks. Since the retransmission is not caused by network drop it should not update the recovery state variables. Further the server may return a smaller MSS than the cached MSS used for SYN-data, so the retranmission needs a loop. Otherwise some data will not be retransmitted until timeout or other loss recovery events. Signed-off-by: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- include/net/tcp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net') diff --git a/include/net/tcp.h b/include/net/tcp.h index 6feeccd83dd7..4af45e33105d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -525,6 +525,7 @@ static inline __u32 cookie_v6_init_sequence(struct sock *sk, extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, int nonagle); extern bool tcp_may_send_now(struct sock *sk); +extern int __tcp_retransmit_skb(struct sock *, struct sk_buff *); extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); extern void tcp_retransmit_timer(struct sock *sk); extern void tcp_xmit_retransmit_queue(struct sock *); -- cgit v1.2.3