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From: Eric Dumazet <eric.dumazet@gmail.com>
To: liujian56@huawei.com
Cc: davem@davemloft.net, kuznet@ms2.inr.ac.ru,
	yoshfuji@linux-ipv6.org, edumazet@google.com, ycheng@google.com,
	hkchu@google.com, netdev@vger.kernel.org, weiyongjun1@huawei.com
Subject: Re: [PATCH] tcp: TCP_USER_TIMEOUT can not work in tcp_probe_timer()
Date: Mon, 11 Sep 2017 08:22:28 -0700	[thread overview]
Message-ID: <1505143348.15310.118.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <1505142785.15310.117.camel@edumazet-glaptop3.roam.corp.google.com>

On Mon, 2017-09-11 at 08:13 -0700, Eric Dumazet wrote:

> You can see we got only 3 probes, not 4.

Here is complete packetdrill test showing that code behaves as expected.

    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0

   +0 < S 0:0(0) win 0 <mss 1460,sackOK,nop,nop,nop,wscale 7>
   +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>

// Client advertises a zero receive window, so we can't send.
  +.1 < . 1:1(0) ack 1 win 0
   +0 accept(3, ..., ...) = 4

   +0 setsockopt(4, SOL_TCP, TCP_USER_TIMEOUT, [3000], 4) = 0
   +0 write(4, ..., 2920) = 2920

// Window probes are scheduled just like RTOs.
  +.3~+.31 > . 0:0(0) ack 1
  +.6~+.62 > . 0:0(0) ack 1
 +1.2~+1.24 > . 0:0(0) ack 1

// Peer opens its window too late !
   +3 < . 1:1(0) ack 1 win 1000
   +0 > R 1:1(0)

  reply	other threads:[~2017-09-11 15:22 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-11  6:27 [PATCH] tcp: TCP_USER_TIMEOUT can not work in tcp_probe_timer() liujian56
2017-09-11 14:49 ` Eric Dumazet
2017-09-11 15:13   ` Eric Dumazet
2017-09-11 15:22     ` Eric Dumazet [this message]
2017-09-12  6:08       ` liujian
2017-09-12 15:05         ` Eric Dumazet
2017-09-12 15:38           ` Eric Dumazet
2017-09-13  6:56             ` liujian
2017-09-13  7:15               ` liujian
2017-09-13 14:40                 ` Eric Dumazet
2017-09-14  3:30                   ` [PATCH net] tcp: update skb->skb_mstamp more carefully Eric Dumazet
2017-09-14  8:17                     ` liujian
2017-09-14 13:57                     ` Neal Cardwell
2017-09-14 16:32                       ` Yuchung Cheng
2017-09-14 16:41                         ` Soheil Hassas Yeganeh
2017-09-15 21:37                     ` David Miller
2017-09-15 23:16                       ` Eric Dumazet
2017-09-15 23:47                         ` [PATCH net] tcp: fix data delivery rate Eric Dumazet
2017-09-16  1:33                           ` Soheil Hassas Yeganeh
2017-09-16 16:07                           ` David Miller

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