From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andres Lagar Cavilla <andreslc@cs.toronto.edu>
Subject: Re: Network freezing for paravirt linux, 3.0.3
Date: Tue, 28 Nov 2006 15:53:50 -0500
Message-ID: <456CA1DE.6080408@cs.toronto.edu>
References: <C1920569.52AE%keir@xensource.com>
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As a coda to this, I found that the network routing scripts did not work 
too well, at least for me. dom0's interface would not respond to ARP 
requests from external hosts trying to find out the MAC address 
corresponding to domU's ip. Simply allowing proxy arp on dom0's 
externally visible interface solved this. Patch below.
Andres

# HG changeset patch
# User andres@plaxico.syslab.sandbox
# Date 1164747038 18000
# Node ID b2440d035bffb61004e0bab09f50d740a2347a91
# Parent  bbcaa0cad3d2b7cf90e935bf1dd61aec129b3252
Fix for network routing setup. Enables proxy arp on dom0's externally 
visble interface.
Signed-ff-by: H. Andres Lagar-Cavilla andreslc@cs.toronto.edu

diff -r bbcaa0cad3d2 -r b2440d035bff tools/examples/network-route
--- a/tools/examples/network-route      Tue Nov 28 13:34:15 2006 +0000
+++ b/tools/examples/network-route      Tue Nov 28 15:50:38 2006 -0500
@@ -16,4 +16,12 @@
 #
 #============================================================================

+dir=$(dirname "$0")
+. "$dir/xen-script-common.sh"
+
+evalVariables "$@"
+
+netdev=${netdev:-eth${vifnum}}
+
 echo 1 >/proc/sys/net/ipv4/ip_forward
+echo 1 >/proc/sys/net/ipv4/conf/${netdev}/proxy_arp

Keir Fraser wrote:

>On 28/11/06 15:08, "Andres Lagar Cavilla" <andreslc@cs.toronto.edu> wrote:
>
>  
>
>>It thus looks like the culprit is netfront, or possibly a
>>netback/netfront interaction (Q: is netback employed in the qemu-dm
>>emulation path, or packets are simply relayed from the tap to vifX.Y?).
>>I would love to provide more information, but I'm unsure where to get it.
>>    
>>
>
>What version of netback are you running? The one from the 3.0.3 release is
>known to have a bug which would cause high-bandwidth transfers to stall.
>
>The offending function is netback.c:tx_add_credit(). You should be able to
>take the version from xen-unstable and copy it into whatever version of
>netback.c you are using.
>
> -- Keir
>
>  
>