Re: [PATCH v5 4/4] ipv4: Namespaceify tcp_fastopen_blackhole_timeout knob

[David Miller]

From: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>
Date: Wed, 27 Sep 2017 11:35:43 +0800

> Different namespace application might require different time period in
> second to disable Fastopen on active TCP sockets.
> 
> Tested:
> Simulate following similar situation that the server's data gets dropped
> after 3WHS.
> C ---- syn-data ---> S
> C <--- syn/ack ----- S
> C ---- ack --------> S
> S (accept & write)
> C?  X <- data ------ S
> 	[retry and timeout]
> 
> And then print netstat of TCPFastOpenBlackhole, the counter increased as
> expected when the firewall blackhole issue is detected and active TFO is
> disabled.
> # cat /proc/net/netstat | awk '{print $91}'
> TCPFastOpenBlackhole
> 1
> 
> Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>

Applied.