hotplug: add openvswitch script

Based on Waldi's RFC at
http://lists.xen.org/archives/html/xen-devel/2012-09/msg00943.html

To use it set vif.default.script="vif-openvswitch" in /etc/xen/xl.conf or use
script=vif-openvswitch in the vif configuration.

Appears to do the right thing for PV and HVM guests (including tap devices)
and with stubdomains.

In order to support VLAN tagging and trunking the "bridge" specified in the
configuration can have a special syntax, that is:

	BRIDGE_NAME[.VLAN][:TRUNK:TRUNK]

e.g.
- xenbr0.99
     add the VIF to VLAN99 on xenbr0
- xenbr0:99:100:101
     add the VIF to xenbr0 as a trunk port receiving VLANs 99, 100 & 101

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: dev@openvswitch.org

2 files changed, 114 insertions, 0 deletions

diff --git a/tools/hotplug/Linux/Makefile b/tools/hotplug/Linux/Makefile
index 06055590f9..99bf87f418 100644
--- a/tools/hotplug/Linux/Makefile
+++ b/tools/hotplug/Linux/Makefile
@@ -13,6 +13,7 @@ XENCOMMONS_SYSCONFIG = init.d/sysconfig.xencommons
 XEN_SCRIPTS = network-bridge vif-bridge
 XEN_SCRIPTS += network-route vif-route
 XEN_SCRIPTS += network-nat vif-nat
+XEN_SCRIPTS += vif-openvswitch
 XEN_SCRIPTS += vif2
 XEN_SCRIPTS += vif-setup
 XEN_SCRIPTS += block
diff --git a/tools/hotplug/Linux/vif-openvswitch b/tools/hotplug/Linux/vif-openvswitch
new file mode 100644
index 0000000000..a8e4fc7d25
--- /dev/null
+++ b/tools/hotplug/Linux/vif-openvswitch
@@ -0,0 +1,113 @@
+#!/bin/bash
+#============================================================================
+# ${XEN_SCRIPT_DIR}/vif-openvswitch
+#
+# Script for configuring a vif in openvswitch mode.
+# The hotplugging system will call this script if it is specified either in
+# the device configuration given to Xend, or the default Xend configuration
+# in ${XEN_CONFIG_DIR}/xend-config.sxp.  If the script is specified in
+# neither of those places, then this script is the default.
+#
+# Usage:
+# vif-openvswitch (add|remove|online|offline)
+#
+# Environment vars:
+# vif         vif interface name (required).
+# XENBUS_PATH path to this device's details in the XenStore (required).
+#
+# Read from the store:
+# bridge  openvswitch to add the vif to (required).
+# ip      list of IP networks for the vif, space-separated (optional).
+#
+# up:
+# Enslaves the vif interface to the bridge and adds iptables rules
+# for its ip addresses (if any).
+#
+# down:
+# Removes the vif interface from the bridge and removes the iptables
+# rules for its ip addresses (if any).
+#============================================================================
+
+dir=$(dirname "$0")
+. "$dir/vif-common.sh"
+
+check_tools()
+{
+    if ! command -v ovs-vsctl > /dev/null 2>&1; then
+        fatal "Unable to find ovs-vsctl tool"
+    fi
+    if ! command -v ip > /dev/null 2>&1; then
+        fatal "Unable to find ip tool"
+    fi
+}
+openvswitch_external_id() {
+    local dev=$1
+    local key=$2
+    local value=$3
+
+    echo "-- set interface $dev external-ids:\"$key\"=\"$value\""
+}
+
+openvswitch_external_id_all() {
+    local dev=$1
+    local frontend_id=$(xenstore_read "$XENBUS_PATH/frontend-id")
+    local vm_path=$(xenstore_read "/local/domain/${frontend_id}/vm")
+    local name=$(xenstore_read "${vm_path}/name")
+    openvswitch_external_id $dev "xen-vm-name" "$name"
+    local uuid=$(xenstore_read "${vm_path}/uuid")
+    openvswitch_external_id $dev "xen-vm-uuid" "$uuid"
+    local mac=$(xenstore_read "$XENBUS_PATH/mac")
+    openvswitch_external_id $dev "attached-mac" "$mac"
+}
+
+add_to_openvswitch () {
+    local dev=$1
+    local bridge="$(xenstore_read_default "$XENBUS_PATH/bridge" "$bridge")"
+    local tag trunk
+
+    if [[ $bridge =~ ^([^.:]+)(\.([[:digit:]]+))?(:([[:digit:]]+(:[[:digit:]]+)*))?$ ]]; then
+        bridge="${BASH_REMATCH[1]}"
+        tag="${BASH_REMATCH[3]}"
+        trunk="${BASH_REMATCH[5]//:/,}"
+    else
+        fatal "No valid bridge was specified"
+    fi
+
+    if [ $trunk ]; then
+        local trunk_arg="trunk=$trunk"
+    fi
+
+    if [ $tag ]; then
+        local tag_arg="tag=$tag"
+    fi
+
+    local vif_details="$(openvswitch_external_id_all $dev)"
+
+    do_or_die ovs-vsctl --timeout=30 \
+        -- --if-exists del-port $dev \
+        -- add-port "$bridge" $dev $tag_arg $trunk_arg $vif_details
+    do_or_die ip link set $dev up
+}
+
+case "$command" in
+    add|online)
+        check_tools
+        setup_virtual_bridge_port $dev
+        add_to_openvswitch $dev
+        ;;
+
+    remove|offline)
+        do_without_error ovs-vsctl --timeout=30 \
+            -- --if-exists del-port $dev
+        do_without_error ip link set $dev down
+        ;;
+esac
+
+if [ "$type_if" = vif ]; then
+    handle_iptable
+fi
+
+log debug "Successful vif-openvswitch $command for $dev."
+if [ "$type_if" = vif -a "$command" = "online" ]; then
+    success
+fi