From be3f52f304767a719d4b0dc07c81a1aaea8432b0 Mon Sep 17 00:00:00 2001
From: Simon Deziel <simon.deziel@gmail.com>
Date: Fri, 11 May 2012 12:00:24 -0400
Subject: [PATCH] Force tap's MAC prefix to "fe"
Setting a high prefix discourages the bridge from adopting the tap's
MAC. Xen is not affected by this since the MAC is forced to
"fe:ff:ff:ff:ff:ff".
This addresses issue #217.
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>
---
tools/kvm-ifup.in | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/kvm-ifup.in b/tools/kvm-ifup.in
index 2e8e0c23c..a5e8c1b85 100644
--- a/tools/kvm-ifup.in
+++ b/tools/kvm-ifup.in
@@ -33,14 +33,20 @@ if [ -x "@SYSCONFDIR@/ganeti/kvm-vif-bridge" ]; then
exec @SYSCONFDIR@/ganeti/kvm-vif-bridge
fi
-ip link set $INTERFACE up
-
if [ "$MODE" = "bridged" ]; then
+ # Fix the autogenerated MAC to have the first octet set to "fe"
+ # to discourage the bridge from using the TAP dev's MAC
+ FIXED_MAC=$(ip link show $INTERFACE | awk '{if ($1 == "link/ether") printf("fe%s",substr($2,3,15))}')
+ ip link set $INTERFACE address $FIXED_MAC
+
+ ip link set $INTERFACE up
ip link set $INTERFACE mtu $(</sys/class/net/${BRIDGE}/mtu)
# Connect the interface to the bridge
brctl addif $BRIDGE $INTERFACE
else
+ ip link set $INTERFACE up
+
if [ -z "$IP" ]; then
echo "Routed NIC but no IP address specified"
exit 1
--
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