Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9e450c1e authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller
Browse files

tcp: better SYNACK sent timestamp 



Detecting spurious SYNACK timeout using timestamp option requires
recording the exact SYNACK skb timestamp. Previously the SYNACK
sent timestamp was stamped slightly earlier before the skb
was transmitted. This patch uses the SYNACK skb transmission
timestamp directly.

Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7c1f0815

net/ipv4/tcp_input.c

+1 −1
Original line number Diff line number Diff line
@@ -6319,7 +6319,7 @@ static void tcp_openreq_init(struct request_sock *req, 
	req->cookie_ts = 0;

	tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;

	tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;

	tcp_rsk(req)->snt_synack = tcp_clock_us();

	tcp_rsk(req)->snt_synack = 0;

	tcp_rsk(req)->last_oow_ack_time = 0;

	req->mss = rx_opt->mss_clamp;

	req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;

net/ipv4/tcp_output.c

+4 −0
Original line number Diff line number Diff line
@@ -3247,7 +3247,11 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, 
		skb->skb_mstamp_ns = cookie_init_timestamp(req);

	else

#endif

	{

		skb->skb_mstamp_ns = tcp_clock_ns();

		if (!tcp_rsk(req)->snt_synack) /* Timestamp first SYNACK */

			tcp_rsk(req)->snt_synack = tcp_skb_timestamp_us(skb);

	}



#ifdef CONFIG_TCP_MD5SIG

	rcu_read_lock();