path: root/net/ipv4/tcp_timer.c
diff options
authorEric Dumazet <edumazet@google.com>2012-10-27 23:16:46 +0000
committerDavid S. Miller <davem@davemloft.net>2012-11-03 14:45:00 -0400
commite6c022a4fa2d2d9ca9d0a7ac3b05ad988f39fc30 (patch)
tree6dcd4e2dfc7895f33329fb16653a93f7d52f4bd7 /net/ipv4/tcp_timer.c
parentnet: Fix continued iteration in rtnl_bridge_getlink() (diff)
tcp: better retrans tracking for defer-accept
For passive TCP connections using TCP_DEFER_ACCEPT facility, we incorrectly increment req->retrans each time timeout triggers while no SYNACK is sent. SYNACK are not sent for TCP_DEFER_ACCEPT that were established (for which we received the ACK from client). Only the last SYNACK is sent so that we can receive again an ACK from client, to move the req into accept queue. We plan to change this later to avoid the useless retransmit (and potential problem as this SYNACK could be lost) TCP_INFO later gives wrong information to user, claiming imaginary retransmits. Decouple req->retrans field into two independent fields : num_retrans : number of retransmit num_timeout : number of timeouts num_timeout is the counter that is incremented at each timeout, regardless of actual SYNACK being sent or not, and used to compute the exponential timeout. Introduce inet_rtx_syn_ack() helper to increment num_retrans only if ->rtx_syn_ack() succeeded. Use inet_rtx_syn_ack() from tcp_check_req() to increment num_retrans when we re-send a SYNACK in answer to a (retransmitted) SYN. Prior to this patch, we were not counting these retransmits. Change tcp_v[46]_rtx_synack() to increment TCP_MIB_RETRANSSEGS only if a synack packet was successfully queued. Reported-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Julian Anastasov <ja@ssi.bg> Cc: Vijay Subramanian <subramanian.vijay@gmail.com> Cc: Elliott Hughes <enh@google.com> Cc: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index fc04711e80c8..62c69ab19fdf 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -318,7 +318,7 @@ static void tcp_fastopen_synack_timer(struct sock *sk)
req = tcp_sk(sk)->fastopen_rsk;
req->rsk_ops->syn_ack_timeout(sk, req);
- if (req->retrans >= max_retries) {
+ if (req->num_timeout >= max_retries) {
@@ -327,10 +327,10 @@ static void tcp_fastopen_synack_timer(struct sock *sk)
* regular retransmit because if the child socket has been accepted
* it's not good to give up too easily.
- req->rsk_ops->rtx_syn_ack(sk, req, NULL);
- req->retrans++;
+ inet_rtx_syn_ack(sk, req);
+ req->num_timeout++;
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
- TCP_TIMEOUT_INIT << req->retrans, TCP_RTO_MAX);
+ TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);