From 72bb6de0e016c567ff17504ac3ca792dc0792471 Mon Sep 17 00:00:00 2001
From: "emellor@leeni.uk.xensource.com" <emellor@leeni.uk.xensource.com>
Date: Thu, 8 Dec 2005 16:11:48 +0000
Subject: [PATCH] Flush the addresses from the new eth0 before trying to add
 the new address to it, when using ip on the kernel command line and not using
 the installed ifup / ifdown.  This stops the script bailing out if there is
 already an address attached to that device, which was leaving the device
 without routing (since this has already been removed).

Fix the stop action under the same circumstances.  No attempt was made to
restore the kernel command line details to the interfaces if the ifdown failed
in that case.

Signed-off-by: Ewan Mellor <ewan@xensource.com>
---
 tools/examples/network-bridge | 61 +++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 25 deletions(-)

diff --git a/tools/examples/network-bridge b/tools/examples/network-bridge
index 2534b928c4..e915ea95e3 100755
--- a/tools/examples/network-bridge
+++ b/tools/examples/network-bridge
@@ -89,6 +89,31 @@ legacy_mask_to_prefix() {
     exit 1
 }
 
+parse_kernel_ip() {
+    if egrep 'ip=[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+:' /proc/cmdline; then
+	kip=`sed -e 's!.*ip=\([0-9]\+\.[0-9]\+\.[0-9]\+\.[0-9]\+\):.*!\1!' /proc/cmdline`
+	kmask=`sed -e 's!.*ip=[^:]*:[^:]*:[^:]*:\([^:]*\):.*!\1!' /proc/cmdline` 
+	kgate=`sed -e 's!.*ip=[^:]*:[^:]*:\([^:]*\):.*!\1!' /proc/cmdline`
+    fi
+}
+
+do_ifup() {
+    if ! ifup $1 ; then
+        if [ ${kip} ] ; then
+            # use the addresses we grocked from /proc/cmdline
+            if [ -z "${kmask}" ]; then 
+                PREFIX=32
+            else 
+                legacy_mask_to_prefix ${kmask}
+            fi
+            ip addr flush $1
+            ip addr add ${kip}/${PREFIX} dev $1
+            ip link set dev $1 up
+            [ ${kgate} ] && ip route add default via ${kgate}
+        fi
+    fi
+}
+
 # Usage: transfer_addrs src dst
 # Copy all IP addresses (including aliases) from device $src to device $dst.
 transfer_addrs () {
@@ -234,14 +259,11 @@ using loopback.nloopbacks=<N> on the domain 0 kernel command line.
 	preiftransfer ${netdev}
 	transfer_addrs ${netdev} ${vdev}
 	if ! ifdown ${netdev}; then
-	    # if ifup didn't work, see if we have an ip= on cmd line
-	    if egrep 'ip=[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+:' /proc/cmdline; then
-		kip=`sed -e 's!.*ip=\([0-9]\+\.[0-9]\+\.[0-9]\+\.[0-9]\+\):.*!\1!' /proc/cmdline`
-		kmask=`sed -e 's!.*ip=[^:]*:[^:]*:[^:]*:\([^:]*\):.*!\1!' /proc/cmdline` 
-		kgate=`sed -e 's!.*ip=[^:]*:[^:]*:\([^:]*\):.*!\1!' /proc/cmdline`
-		ip link set ${netdev} down
-		ip addr flush ${netdev}
-	    fi
+	    # If ifdown fails, take the IP details from the kernel command
+	    # line.
+	    parse_kernel_ip
+	    ip link set ${netdev} down
+	    ip addr flush ${netdev}
 	fi
 	ip link set ${netdev} name ${pdev}
 	ip link set ${vdev} name ${netdev}
@@ -253,20 +275,8 @@ using loopback.nloopbacks=<N> on the domain 0 kernel command line.
 	add_to_bridge ${bridge} ${pdev}
 	ip link set ${bridge} up
 	ip link set ${vif0} up
-	ip link set ${pdev} up 
-	if ! ifup ${netdev} ; then
-	    if [ ${kip} ] ; then
-		# use the addresses we grocked from /proc/cmdline
-		if [ -z "${kmask}" ]; then 
-		    PREFIX=32; 
-		else 
-		    legacy_mask_to_prefix ${kmask};
-		fi
-		ip addr add ${kip}/${PREFIX} dev ${netdev}
-		ip link set dev ${netdev} up
-		[ ${kgate} ] && ip route add default via ${kgate}
-	    fi
-	fi
+	ip link set ${pdev} up
+	do_ifup ${netdev}
     else
 	# old style without ${vdev}
 	transfer_addrs  ${netdev} ${bridge}
@@ -290,7 +300,9 @@ op_stop () {
 	ip link set dev ${vif0} down
 	mac=`ip link show ${netdev} | grep 'link\/ether' | sed -e 's/.*ether \(..:..:..:..:..:..\).*/\1/'`
 	transfer_addrs ${netdev} ${pdev}
-	ifdown ${netdev}
+	if ! ifdown ${netdev}; then
+	    parse_kernel_ip
+	fi
 	ip link set ${netdev} down arp off
 	ip link set ${netdev} addr fe:ff:ff:ff:ff:ff
 	ip link set ${pdev} down
@@ -303,8 +315,7 @@ op_stop () {
 
 	ip link set ${netdev} name ${vdev}
 	ip link set ${pdev} name ${netdev}
-	ifup ${netdev}
-
+	do_ifup ${netdev}
     else
 	transfer_routes ${bridge} ${netdev}
 	ip link set ${bridge} down
-- 
2.30.2