From 3683290fc0b0d6500392db733811cc78bcb35eab Mon Sep 17 00:00:00 2001
From: Paul Durrant <pdurrant@amazon.com>
Date: Fri, 8 Nov 2019 09:42:33 +0000
Subject: [PATCH] tools/hotplug: only attempt to call 'ip route' if there is
 valid command

The vif-route script should only call 'ip route' when 'ipcmd' has been
set, otherwise it will fail due to an incorrect command string.

This patch also adds routes for 'tap' (i.e. emulated) devices as well as
'vif' (i.e. PV) devices. Empirically offline/online commands relate to
'vif' devices, and add/remove commands relate to 'tap' devices. However,
this patch treats them equally and uses ${type_if} to distinguish. By
adding cases for add/remove the command list becomes exhaustive and hence
'ipcmd' is guaranteed to be set.

Routes for 'tap' and 'vif' devices are distinguished by a route metric.
Emulated devices are used by HVM guests until they are unplugged, at which
point the PV device becomes active. Thus 'tap' devices should get a higher
priority (i.e. lower numbered) metric than 'vif' devices.

There is also one small whitespace fix.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Acked-by: Wei Liu <wl@xen.org>
Release-acked-by: Juergen Gross <jgross@suse.com>
---
 tools/hotplug/Linux/vif-route | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)
 mode change 100644 => 100755 tools/hotplug/Linux/vif-route

diff --git a/tools/hotplug/Linux/vif-route b/tools/hotplug/Linux/vif-route
old mode 100644
new mode 100755
index c149ffca73..05199bf741
--- a/tools/hotplug/Linux/vif-route
+++ b/tools/hotplug/Linux/vif-route
@@ -22,12 +22,16 @@ dir=$(dirname "$0")
 main_ip=$(dom0_ip)
 
 case "${command}" in
+    add)
+        ;&
     online)
         ifconfig ${dev} ${main_ip} netmask 255.255.255.255 up
         echo 1 >/proc/sys/net/ipv4/conf/${dev}/proxy_arp
         ipcmd='add'
         cmdprefix=''
         ;;
+    remove)
+        ;&
     offline)
         do_without_error ifdown ${dev}
         ipcmd='del'
@@ -35,13 +39,23 @@ case "${command}" in
         ;;
 esac
 
-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
-      ${cmdprefix} ip route ${ipcmd} ${addr} dev ${dev} src ${main_ip}
-    done
-fi
+case "${type_if}" in
+    tap)
+	metric=1
+	;;
+    vif)
+	metric=2
+	;;
+    *)
+	fatal "Unrecognised interface type ${type_if}"
+	;;
+esac
+
+# 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
+    ${cmdprefix} ip route ${ipcmd} ${addr} dev ${dev} src ${main_ip} metric ${metric}
+done
 
 handle_iptable
 
@@ -50,5 +64,5 @@ call_hooks vif post
 log debug "Successful vif-route ${command} for ${dev}."
 if [ "${command}" = "online" ]
 then
-  success
+    success
 fi
-- 
2.30.2