diff options
authorYuchung Cheng <ycheng@google.com>2017-12-07 11:33:30 -0800
committerDavid S. Miller <davem@davemloft.net>2017-12-08 14:14:11 -0500
commit0ce294d88457bccd7f9991f883fec80022a1ddbd (patch)
parent2edbdb3159d6f6bd3a9b6e7f789f2b879699a519 (diff)
tcp: correctly test congestion state in RACK
RACK does not test the loss recovery state correctly to compute the reordering window. It assumes if lost_out is zero then TCP is not in loss recovery. But it can be zero during recovery before calling tcp_rack_detect_loss(): when an ACK acknowledges all packets marked lost before receiving this ACK, but has not yet to discover new ones by tcp_rack_detect_loss(). The fix is to simply test the congestion state directly. Signed-off-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Priyaranjan Jha <priyarjha@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c
index d3ea89020c69..3143664902e9 100644
--- a/net/ipv4/tcp_recovery.c
+++ b/net/ipv4/tcp_recovery.c
@@ -55,7 +55,8 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout)
* to queuing or delayed ACKs.
reo_wnd = 1000;
- if ((tp->rack.reord || !tp->lost_out) && min_rtt != ~0U) {
+ if ((tp->rack.reord || inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery) &&
+ min_rtt != ~0U) {
reo_wnd = max((min_rtt >> 2) * tp->rack.reo_wnd_steps, reo_wnd);
reo_wnd = min(reo_wnd, tp->srtt_us >> 3);