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Commit 7e32b443 authored Sep 21, 2016 by Yuchung Cheng Committed by David S. Miller Sep 22, 2016

tcp: properly account Fast Open SYN-ACK retrans



Since the TFO socket is accepted right off SYN-data, the socket
owner can call getsockopt(TCP_INFO) to collect ongoing SYN-ACK
retransmission or timeout stats (i.e., tcpi_total_retrans,
tcpi_retransmits). Currently those stats are only updated
upon handshake completes. This patch fixes it.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent de1d6578

net/ipv4/tcp_input.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5885,7 +5885,7 @@ int tcp_rcv_state_process(struct sock sk, struct sk_buff skb)
		* so release it.
		*/
		if (req) {
		tp->total_retrans = req->num_retrans;
		inet_csk(sk)->icsk_retransmits = 0;
		reqsk_fastopen_remove(sk, req, false);
		} else {
		/* Make sure socket is routed, for correct metrics. */

net/ipv4/tcp_output.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -3568,6 +3568,8 @@ int tcp_rtx_synack(const struct sock sk, struct request_sock req)
		if (!res) {
		__TCP_INC_STATS(sock_net(sk), TCP_MIB_RETRANSSEGS);
		__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNRETRANS);
		if (unlikely(tcp_passive_fastopen(sk)))
		tcp_sk(sk)->total_retrans++;
		}
		return res;
		}

net/ipv4/tcp_timer.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -384,6 +384,7 @@ static void tcp_fastopen_synack_timer(struct sock *sk)
		*/
		inet_rtx_syn_ack(sk, req);
		req->num_timeout++;
		icsk->icsk_retransmits++;
		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
		TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
		}