Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread David Miller
From: Benjamin LaHaise <[EMAIL PROTECTED]> Date: Tue, 1 May 2007 15:19:31 -0400 > On Tue, May 01, 2007 at 02:03:04PM -0400, John Heffner wrote: > > Being liberal in what you accept is good to a point, but sometimes you > > have to draw the line. > > True. Still, both sides are doing completely

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Benjamin LaHaise
On Tue, May 01, 2007 at 02:03:04PM -0400, John Heffner wrote: > Actually, you cannot get in this situation by loss or reordering of > packets, only be corruption of state on one side. It sends the FIN, > which effectively increases the sequence number by one. However, all > later segments it s

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Evgeniy Polyakov
On Tue, May 01, 2007 at 10:20:07PM +0400, Evgeniy Polyakov ([EMAIL PROTECTED]) wrote: > On Tue, May 01, 2007 at 11:13:54AM -0400, Benjamin LaHaise ([EMAIL > PROTECTED]) wrote: > > Hello, > > > > While testing a failover scenario, I managed to trigger an ack storm > > between a Linux box and ano

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Evgeniy Polyakov
On Tue, May 01, 2007 at 11:13:54AM -0400, Benjamin LaHaise ([EMAIL PROTECTED]) wrote: > Hello, > > While testing a failover scenario, I managed to trigger an ack storm > between a Linux box and another system. Although the cause of this > particular > ACK storm was due to the other box forget

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread John Heffner
Benjamin LaHaise wrote: On Tue, May 01, 2007 at 09:41:28PM +0400, Evgeniy Polyakov wrote: Hmm, 2.2 machine in your test seems to behave incorrectly: I am aware of that. However, I think that the loss of certain packets and reordering can result in the same behaviour. What's more, is that th

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Evgeniy Polyakov
On Tue, May 01, 2007 at 02:04:05PM -0400, Benjamin LaHaise ([EMAIL PROTECTED]) wrote: > I know it's a bug, and I'm trying to fix it, but that doesn't change the > fact that A) the system is already deployed and B) Linux is not > retransmitting > the FIN, which (from Linux's point of view) remai

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Benjamin LaHaise
On Tue, May 01, 2007 at 01:54:03PM -0400, John Heffner wrote: > Looking at your trace, it seems like the behavior of the test system > 192.168.2.2 is broken in two ways. First, like you said it has broken > state in that it has forgotten that it sent the FIN. Once you do that, > the connection

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Evgeniy Polyakov
On Tue, May 01, 2007 at 09:57:18PM +0400, Evgeniy Polyakov ([EMAIL PROTECTED]) wrote: > > I think if you will storm any system with acks lower than expected > > unacknowledged number, result will be the same - ack, that it was bogus > > message, if sending system sends wrong ack again, it will aga

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread John Heffner
Benjamin LaHaise wrote: According to your patch, several packets with fin bit might be sent, including one with data. If another host does not receive fin retransmit, then that logic is broken, and it can not be fixed by duplicating fins, I would even say, that remote box should drop second packe

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Evgeniy Polyakov
On Tue, May 01, 2007 at 09:41:28PM +0400, Evgeniy Polyakov ([EMAIL PROTECTED]) wrote: > On Tue, May 01, 2007 at 12:49:35PM -0400, Benjamin LaHaise ([EMAIL > PROTECTED]) wrote: > > On Tue, May 01, 2007 at 08:20:50PM +0400, Evgeniy Polyakov wrote: > > > > http://www.kvack.org/~bcrl/ack-storm.log .

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Benjamin LaHaise
On Tue, May 01, 2007 at 09:41:28PM +0400, Evgeniy Polyakov wrote: > Hmm, 2.2 machine in your test seems to behave incorrectly: I am aware of that. However, I think that the loss of certain packets and reordering can result in the same behaviour. What's more, is that this behaviour can occur in

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Evgeniy Polyakov
On Tue, May 01, 2007 at 12:49:35PM -0400, Benjamin LaHaise ([EMAIL PROTECTED]) wrote: > On Tue, May 01, 2007 at 08:20:50PM +0400, Evgeniy Polyakov wrote: > > > http://www.kvack.org/~bcrl/ack-storm.log . As near as I can tell, a > > > similar effect can occur between two Linux boxes if the right

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Benjamin LaHaise
On Tue, May 01, 2007 at 08:20:50PM +0400, Evgeniy Polyakov wrote: > > http://www.kvack.org/~bcrl/ack-storm.log . As near as I can tell, a > > similar effect can occur between two Linux boxes if the right packets get > > reordered/dropped during connection teardown. > > Could you archive 24Mb fi

Re: [PATCH] TCP FIN gets dropped prematurely, results in ack storm

2007-05-01 Thread Evgeniy Polyakov
On Tue, May 01, 2007 at 11:13:54AM -0400, Benjamin LaHaise ([EMAIL PROTECTED]) wrote: > Hello, Hi Benjamin. > While testing a failover scenario, I managed to trigger an ack storm > between a Linux box and another system. Although the cause of this > particular > ACK storm was due to the othe