[RFC] openvswitch support script

[Bastian Blank <waldi@debian.org>]

Hi

I wrote a vif script to support openvswitch. I use it on some of my
machines, so it works for non-qemu domains.

Ian asked me to send it here, maybe someone wants to take a look.

Bastian

#!/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"

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 brdige 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)"

    ovs-vsctl --timeout=30 -- --if-exists del-port $dev -- add-port "$bridge" $dev $tag_arg $trunk_arg $vif_details
    ip link set $dev up
}

case "$command" in
    add|online)
        setup_virtual_bridge_port $dev
        add_to_openvswitch $dev
        ;;

    offline)
        ovs-vsctl --timeout=30 -- --if-exists del-port $dev
        ;;
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
-- 
Is truth not truth for all?
		-- Natira, "For the World is Hollow and I have Touched
		   the Sky", stardate 5476.4.