Subject: Re: Possible networking regression in 3.6.0

From: Chris Clayton <[email-masked]>
Date: Thu, 27 Sep 2012 12:50:57 +0100

Just for information - I've pulled Linus' tree this morning and the 
problem is still present. Also, Gunther Piaz has reported, via the 
bugzilla entry, that he too has hit this regression.

On 09/22/12 07:26, Chris Clayton wrote:
> I guess you network developer folks are either very busy or this
> regression is proving a bit troublesome to identify, so I've opened a
> bugzilla report to keep track of it. The report number is 47761.
>
> Chris
>
> On 09/19/12 16:26, Chris Clayton wrote:
>>>
>>> It would help to have some traffic sample, maybe.
>>>
>>> Especially if the problem is not easily reproductible for us.
>>>
>>
>> OK, I've used an netsniff-ng to capture the traffic on all interfaces on
>> the host (that would be tap0 and eth0, I guess) whilst attempting to
>> ping the router from the WinXP KVM client. The result is a pcap file
>> that I processed with tcpdump to produce:
>>
>> reading from file net-trace.pcap, link-type EN10MB (Ethernet)
>> 14:56:31.406336 ARP, Request who-has 192.168.200.254 tell 192.168.200.1,
>> length 28
>>          0x0000:  0001 0800 0604 0001 5254 0c3b 1728 c0a8
>>          0x0010:  c801 0000 0000 0000 c0a8 c8fe
>> 14:56:31.406357 ARP, Reply 192.168.200.254 is-at 46:83:93:8f:f0:7e,
>> length 28
>>          0x0000:  0001 0800 0604 0002 4683 938f f07e c0a8
>>          0x0010:  c8fe 5254 0c3b 1728 c0a8 c801
>> 14:56:31.406534 IP 192.168.200.1 > 192.168.0.1: ICMP echo request, id
>> 512, seq 4352, length 40
>>          0x0000:  4500 003c 0195 0000 8001 efd8 c0a8 c801
>>          0x0010:  c0a8 0001 0800 3a5c 0200 1100 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:31.406566 ARP, Request who-has 192.168.0.1 tell 192.168.0.40,
>> length 28
>>          0x0000:  0001 0800 0604 0001 5c9a d85c 6331 c0a8
>>          0x0010:  0028 0000 0000 0000 c0a8 0001
>> 14:56:31.410830 ARP, Reply 192.168.0.1 is-at 00:1f:33:80:09:44, length 46
>>          0x0000:  0001 0800 0604 0002 001f 3380 0944 c0a8
>>          0x0010:  0001 5c9a d85c 6331 c0a8 0028 c0a8 0001
>>          0x0020:  e000 0001 1164 ee9b 0000 0000 4500
>> 14:56:31.410851 IP 192.168.0.40 > 192.168.0.1: ICMP echo request, id
>> 512, seq 4352, length 40
>>          0x0000:  4500 003c 0195 0000 7f01 b8b2 c0a8 0028
>>          0x0010:  c0a8 0001 0800 3a5c 0200 1100 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:31.414474 IP 192.168.0.1 > 192.168.0.40: ICMP echo reply, id 512,
>> seq 4352, length 40
>>          0x0000:  4500 003c cf4f 0000 ff01 6af7 c0a8 0001
>>          0x0010:  c0a8 0028 0000 425c 0200 1100 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:36.404781 ARP, Request who-has 192.168.0.40 tell 192.168.0.1,
>> length 46
>>          0x0000:  0001 0800 0604 0001 001f 3380 0944 c0a8
>>          0x0010:  0001 0000 0000 0000 c0a8 0028 c0a8 0001
>>          0x0020:  c0a8 0028 0000 425c 0200 1100 6162
>> 14:56:36.404806 ARP, Reply 192.168.0.40 is-at 5c:9a:d8:5c:63:31,
>> length 28
>>          0x0000:  0001 0800 0604 0002 5c9a d85c 6331 c0a8
>>          0x0010:  0028 001f 3380 0944 c0a8 0001
>> 14:56:36.689750 IP 192.168.200.1 > 192.168.0.1: ICMP echo request, id
>> 512, seq 4608, length 40
>>          0x0000:  4500 003c 0196 0000 8001 efd7 c0a8 c801
>>          0x0010:  c0a8 0001 0800 395c 0200 1200 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:36.689774 IP 192.168.0.40 > 192.168.0.1: ICMP echo request, id
>> 512, seq 4608, length 40
>>          0x0000:  4500 003c 0196 0000 7f01 b8b1 c0a8 0028
>>          0x0010:  c0a8 0001 0800 395c 0200 1200 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:36.693330 IP 192.168.0.1 > 192.168.0.40: ICMP echo reply, id 512,
>> seq 4608, length 40
>>          0x0000:  4500 003c cf50 0000 ff01 6af6 c0a8 0001
>>          0x0010:  c0a8 0028 0000 415c 0200 1200 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:42.189424 IP 192.168.200.1 > 192.168.0.1: ICMP echo request, id
>> 512, seq 4864, length 40
>>          0x0000:  4500 003c 0197 0000 8001 efd6 c0a8 c801
>>          0x0010:  c0a8 0001 0800 385c 0200 1300 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:42.189447 IP 192.168.0.40 > 192.168.0.1: ICMP echo request, id
>> 512, seq 4864, length 40
>>          0x0000:  4500 003c 0197 0000 7f01 b8b0 c0a8 0028
>>          0x0010:  c0a8 0001 0800 385c 0200 1300 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:42.193029 IP 192.168.0.1 > 192.168.0.40: ICMP echo reply, id 512,
>> seq 4864, length 40
>>          0x0000:  4500 003c cf51 0000 ff01 6af5 c0a8 0001
>>          0x0010:  c0a8 0028 0000 405c 0200 1300 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:47.689414 IP 192.168.200.1 > 192.168.0.1: ICMP echo request, id
>> 512, seq 5120, length 40
>>          0x0000:  4500 003c 0198 0000 8001 efd5 c0a8 c801
>>          0x0010:  c0a8 0001 0800 375c 0200 1400 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:47.689439 IP 192.168.0.40 > 192.168.0.1: ICMP echo request, id
>> 512, seq 5120, length 40
>>          0x0000:  4500 003c 0198 0000 7f01 b8af c0a8 0028
>>          0x0010:  c0a8 0001 0800 375c 0200 1400 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>> 14:56:47.693661 IP 192.168.0.1 > 192.168.0.40: ICMP echo reply, id 512,
>> seq 5120, length 40
>>          0x0000:  4500 003c cf52 0000 ff01 6af4 c0a8 0001
>>          0x0010:  c0a8 0028 0000 3f5c 0200 1400 6162 6364
>>          0x0020:  6566 6768 696a 6b6c 6d6e 6f70 7172 7374
>>          0x0030:  7576 7761 6263 6465 6667 6869
>>
>> Is this what you asked for?
>>
>> Chris
>>
>
>