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authorEric Dumazet <eric.dumazet@gmail.com>2011-09-23 00:02:19 +0400
committerDavid S. Miller <davem@davemloft.net>2011-09-27 08:58:44 +0400
commit7a269ffad72f3604b8982fa09c387670e0d2ee14 (patch)
tree3655a22066bcb1011e5e1b717a00a108143dfd85 /include/net/tcp.h
parent0bdb0bd0139f3b6afa252de1487e3ce82a494db9 (diff)
downloadlinux-7a269ffad72f3604b8982fa09c387670e0d2ee14.tar.xz
tcp: ECN blackhole should not force quickack mode
While playing with a new ADSL box at home, I discovered that ECN blackhole can trigger suboptimal quickack mode on linux : We send one ACK for each incoming data frame, without any delay and eventual piggyback. This is because TCP_ECN_check_ce() considers that if no ECT is seen on a segment, this is because this segment was a retransmit. Refine this heuristic and apply it only if we seen ECT in a previous segment, to detect ECN blackhole at IP level. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Jamal Hadi Salim <jhs@mojatatu.com> CC: Jerry Chu <hkchu@google.com> CC: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> CC: Jim Gettys <jg@freedesktop.org> CC: Dave Taht <dave.taht@gmail.com> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/tcp.h')
-rw-r--r--include/net/tcp.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index f357befaaa01..702aefc8d43d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -356,6 +356,7 @@ static inline void tcp_dec_quickack_mode(struct sock *sk,
#define TCP_ECN_OK 1
#define TCP_ECN_QUEUE_CWR 2
#define TCP_ECN_DEMAND_CWR 4
+#define TCP_ECN_SEEN 8
static __inline__ void
TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)