netdev - Re: [CRIU] TCP_REPAIR MSS issue

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Date:	Mon, 18 Jul 2016 09:06:05 +0000
From:	"Eggert, Lars" <lars@...app.com>
To:	Andrey Vagin <avagin@...tuozzo.com>
CC:	Pavel Emelyanov <xemul@...tuozzo.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"criu@...nvz.org" <criu@...nvz.org>,
	"Honda, Michio" <michio@...app.com>
Subject: Re: [CRIU] TCP_REPAIR MSS issue

Hi,

On 2016-06-16, at 23:09, Andrey Vagin <avagin@...tuozzo.com> wrote:
> I can't reproduce this issue, now I'm trying to understand why it works
> for me and doesn't work for you.

just to conclude this thread for the list:

Andrey and me debugged this off-list. The issue arose, because my code did a bind() to 0.0.0.0 in TCP_REPAIR mode. When turning off TCP_REPAIR and sending into the socket, this caused minimum-MSS-sized segments to be transmitted. The issue goes away when I bind() to the local IP address of my local egress interface.

To me at least, this is a POLA violation (excuse the FreeBSD terminology :-) Either binding to 0.0.0.0 should fail, or it should succeed and full-sized segments should be sent. But at least I have a work-around now.

Thanks,
Lars

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