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From: David Newall <davidn@davidnewall.com>
To: Florian Westphal <fw@strlen.de>,
	Lennert Buytenhek <buytenh@gnu.org>,
	Bart De Schuymer <bdschuym@pandora.be>
Cc: Netdev <netdev@vger.kernel.org>
Subject: Re: Bad checksum on bridge with IP options
Date: Mon, 12 May 2014 23:49:30 +0930	[thread overview]
Message-ID: <5370D872.8080901@davidnewall.com> (raw)
In-Reply-To: <20140512135141.GA13945@breakpoint.cc>

On 12/05/14 23:21, Florian Westphal wrote:
> Agree, bridge should not alter ip options.

It would be easy to remove the call to ip_options_compile instead of 
recalculating checksum after it, but I suspect there may be good reasons 
why this, too, would be wrong.  The source file is br_netfilter.c, 
suggesting that a change in options is needed in some situations.

In the situation that caught my attention, it obviously does it wrong 
(probably didn't add 0.0.0.0 to the route record, probably just 
incremented the pointer; and seriously damaged the timestamps as well as 
an incremented pointer without actually adding a value.)

I'm in a quandary.

Is it possible that bridge has exceeded it's mandate?  I can't find it 
now, but I saw a comment that it just copies packets unchanged. I think 
it's use now goes further than that would allow.

I welcome words of advice.

  reply	other threads:[~2014-05-12 14:19 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-11 14:41 Bad checksum on bridge with IP options David Newall
2014-05-11 19:42 ` Lukas Tribus
2014-05-12  8:14   ` David Newall
2014-05-12 10:15     ` Lukas Tribus
2014-05-12 10:25       ` David Newall
2014-05-12 10:31         ` Lukas Tribus
2014-05-12 10:48           ` David Newall
2014-05-12 13:23 ` David Newall
2014-05-12 13:51   ` Florian Westphal
2014-05-12 14:19     ` David Newall [this message]
2014-05-12 18:54   ` Lukas Tribus
2014-05-12 23:46     ` David Newall
2014-05-14 13:08       ` David Newall
2014-05-16 14:33         ` Revert 462fb2af9788a82a534f8184abfde31574e1cfa0 (bridge : Sanitize skb before it enters the IP stack) David Newall
2014-05-16 15:19           ` Eric Dumazet
2014-05-16 15:23             ` David Newall
2014-05-16 15:24             ` David Newall
2014-05-19 12:58           ` David Newall
2014-05-19 14:01             ` Florian Westphal
2014-05-19 14:19               ` David Newall
2014-05-19 17:09                 ` Florian Westphal
2014-05-19 20:49                   ` Bart De Schuymer
2014-05-21  7:49                     ` David Newall
2014-05-21 18:51                       ` Bart De Schuymer
2014-05-21 20:18                         ` David Miller
2014-05-22 18:57                           ` Bart De Schuymer
2014-05-24 18:00                             ` David Miller
2014-05-24  5:56                           ` David Newall
2014-05-24 17:43                             ` David Miller
2014-05-25  2:32                               ` David Newall
2014-05-25  3:02                                 ` David Miller
2014-05-25  6:37                                   ` David Newall
2014-05-27  8:55                                 ` David Laight
2014-05-29 22:34                                 ` David Miller
2014-05-30  9:17                                   ` David Newall
2014-05-31  0:46                                     ` David Miller
2014-05-31  6:13                                       ` David Newall
2014-05-31  6:37                                         ` David Miller
2014-05-22  3:50                         ` David Newall
2014-05-22 18:57                           ` Bart De Schuymer
2014-05-20  3:57                   ` David Newall
2014-05-20  4:55                 ` Valdis.Kletnieks
2014-05-20 16:05                   ` Vlad Yasevich
2014-05-21  8:10                   ` David Newall
2014-05-21 20:14                     ` David Miller
2014-05-22 20:06           ` Bandan Das

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