Re: [Xen-devel] ARP problems with xen 4.0 with pvops kernel

["Luís Silva" <luis.silva@axiomasoft.pt>]

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Hello,

I'm using the latest stable-2.6.32.x. I already tried "ethtool -K
<bridge> tx off", but that didn't make any difference. Also, this only
happen with pv, in hvm mode all works ok and the domU sees the arp
messages...

Thanks,
Luís

On Tue, 2010-06-01 at 18:20 -0700, Jeremy Fitzhardinge wrote:

> On 06/01/2010 05:38 PM, Luís Silva wrote:
> > Hello,
> >
> > Finally I managed to get a xen 4.0 working on ubuntu 10.04 with pvops
> > kernel and libvirt. However I am having some problems with
> > networking... after initial installation with netinstall image in hvm
> > mode, when I transform the vm in xen pv (via pygrub with the current
> > ubuntu kernel), networking startEd to act weird...
> >
> > Basically I'm not using a network script from xen. I define a bridge
> > (manually or via libvirt, the result is the same) and I use vif-bridge
> > to connect the vif to it. But now the weird part comes: I can
> > communicate from domU to dom0, but not the other way around, unless I
> > keep a ping running from domU to dom0... That's right, weird... while
> > trying the ping from dom0 to domU, I used tcpdump both on the bridge,
> > on the vif and on the eth0 in the domU. The arp packets never get to
> > domU, but they appear both in the bridge and the vif sniff's...
> 
> What version of kernel are you using in dom0 and domU?  There was a
> netback bug which caused problems with dom0<->domU communication, but it
> has been fixed for a while in 2.6.32 (but only recently in .31).  The
> workaround is to disable tx checksum offload on your bridge (ethtool -K
> <bridge> tx off).
> 
>     J
> 
> >
> > Here is the bridge:
> > ifconfig virbr0
> > virbr0    Link encap:Ethernet  HWaddr fe:ff:ff:ff:ff:ff  
> >           inet addr:192.168.120.254  Bcast:192.168.120.255  Mask:255.255.255.0
> >           inet6 addr: fe80::7cee:4bff:fe82:e63f/64 Scope:Link
> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> >           RX packets:16 errors:0 dropped:0 overruns:0 frame:0
> >           TX packets:226 errors:0 dropped:0 overruns:0 carrier:0
> >           collisions:0 txqueuelen:0 
> >           RX bytes:952 (952.0 B)  TX bytes:13953 (13.9 KB)
> >
> >
> > brctl show
> > bridge name	bridge id		STP enabled	interfaces
> > virbr0		8000.feffffffffff	no		vif5.0
> >
> >
> > tcpdump -i virbr0 -vv -n
> > tcpdump: listening on virbr0, link-type EN10MB (Ethernet), capture size 96 bytes
> > 01:31:25.945151 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 1, length 64
> > 01:31:26.945361 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 2, length 64
> > 01:31:27.945420 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 3, length 64
> > 01:31:28.945362 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 4, length 64
> > 01:31:29.945364 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 5, length 64
> > 01:31:30.944300 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:30.945359 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 6, length 64
> > 01:31:31.944297 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:31.945444 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 7, length 64
> > 01:31:32.944294 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:32.945401 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
> >     192.168.120.254 > 192.168.120.1: ICMP echo request, id 10317, seq 8, length 64
> > 01:31:33.947293 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:34.947373 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:35.947353 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:37.948352 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:38.948399 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:39.948376 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:31:40.949356 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> >
> >
> > tcpdump -i vif5.0 -vv -n
> > tcpdump: WARNING: vif5.0: no IPv4 address assigned
> > tcpdump: listening on vif5.0, link-type EN10MB (Ethernet), capture size 96 bytes
> > 01:32:19.956358 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:20.956358 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:21.956359 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:23.957311 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:24.957312 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:25.957359 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:27.958360 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:28.958310 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> > 01:32:29.958362 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.120.1 tell 192.168.120.254, length 28
> >   
> >
> >
> > Forwarding and iptables don't seem to be the problem, because if I
> > initiate a ping from domU (at the same time as the failing one from
> > dom0), the ping in dom0 starts to work. As soon as I stop the ping in
> > domU, the one in dom0 starts failing again...
> >
> > Is anyone having the same problem? Is this a bug in the kernel? In
> > dom0 or domU?
> >
> > Thanks in advance,
> > Luís
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com
> > http://lists.xensource.com/xen-devel
> >   
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 



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