vif-route script exits early when deleting vifs

I have experienced that the vif-route script does not work as expected when deleting a virtual interface (Redhat FC5). Both of the commands "ifdown" and "ip route" cause an early vif-route script exit and therefore will cause skipping of the later script commands (such as cleaning up iptables entries for the default 'antispoof'). The vif-route script creates the following syslog error entry: "/etc/xen/scripts/vif-route failed; error detected."

It appears that both of the problematic commands are actually redundant when destroying domains:
1. the interface is already gone (I assume because the domain frontend is gone already) --> ifdown does not do anything
2. the route is gone as well since the interface has disappeared --> ip route del does not do anything

Executing those redundant commands with "do_without_error" ensures that the script completes and cleans up iptables rules. The attached RFC-patch only masks those commands when bringing down an interface, so that domain creation continues to fail in case of vif setup problems (intended behavior).

Having the iptables cleanup called correctly by vif-route is important to keep the iptables rule-set clean, otherwise antispoof rules accumulate with every vif creation..

Comments welcome.

Reiner

Signed-off by: Reiner Sailer <[email protected]>

---
 tools/examples/vif-route |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Index: xen-unstable.hg_test/tools/examples/vif-route
===================================================================
@@ -30,10 +30,12 @@ case "$command" in
         ifconfig ${vif} ${main_ip} netmask 255.255.255.255 up
         echo 1 >/proc/sys/net/ipv4/conf/${vif}/proxy_arp
         ipcmd='add'
+        cmdprefix=''
         ;;
     offline)
-        ifdown ${vif}
+        do_without_error ifdown ${vif}
         ipcmd='del'
+        cmdprefix='do_without_error'
         ;;
 esac
 

@@ -41,7 +43,7 @@ if [ "${ip}" ] ; then
     # If we've been given a list of IP addresses, then add routes from dom0 to
     # the guest using those addresses.
     for addr in ${ip} ; do
-      ip route ${ipcmd} ${addr} dev ${vif} src ${main_ip}
+      ${cmdprefix} ip route ${ipcmd} ${addr} dev ${vif} src ${main_ip}
     done 
 fi
 

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