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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Ben Greear <greearb@candelatech.com>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: More details on why received UDP packets are treated as errors?
Date: Mon, 29 Jul 2013 13:21:32 -0700	[thread overview]
Message-ID: <1375129292.10515.21.camel@edumazet-glaptop> (raw)
In-Reply-To: <51F6B2AB.5050607@candelatech.com>

On Mon, 2013-07-29 at 11:21 -0700, Ben Greear wrote:
> We have a test case on 3.9.9+ (local patches applied) where sending from
> VETH interface, through peer VETH bridged (with our own emulator bridge module)
> to physical interface, which is then looped to another physical interface (B).
> The VETH and the wired B interface are sending UDP traffic to each other.
> Routing rules should be configured such that this all works appropriately.
> 
> Replacing our bridging module with a user-space bridge has same behaviour.
> 
> This setup works on the 3.7.y kernel, but we only get one-way traffic
> (B to VETH) on 3.9.9+.
> 
> I sniffed the B port, and traffic appears to be sent and received
> properly (ie, no checksum errors, etc).  But, our user-space app
> shows no received UDP frames on B, and netstat -s gives the
> output below.
> 
> Is there any way to get more details about what these 'packet receive errors'
> are caused by using normal-ish tools?

You could try dropwatch for this kind of obscure drops

https://fedorahosted.org/dropwatch/

  reply	other threads:[~2013-07-29 20:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-29 18:21 More details on why received UDP packets are treated as errors? Ben Greear
2013-07-29 20:21 ` Eric Dumazet [this message]
2013-07-30 20:38   ` Benjamin Poirier
2013-08-08  0:10   ` Ben Greear

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