openvswitch: support setting OpenFlow datapath ID

By default, Open vSwitch will generate the OpenFlow datapath ID of a
bridge based on the MAC address of one of its ports. Due to this, it's
possible that the datapath ID changes when new ports are added. When the
datapath ID changes, Open vSwitch disconnects from the controller, as
there is no way to notify the controller that the datapath ID has
changed.

Add an option to set the datapath ID so that the above situation can be
avoided. The option takes either exactly 16 hex characters, or when
prefixed with 0x, between 1 and 16 hex characters.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>

net/openvswitch/Makefile

@@ -17,7 +17,7 @@ include ./openvswitch.mk
 #
 PKG_NAME:=openvswitch
 PKG_VERSION:=$(ovs_version)
-PKG_RELEASE:=4
+PKG_RELEASE:=5
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://www.openvswitch.org/releases/
 PKG_HASH:=7d5797f2bf2449c6a266149e88f72123540f7fe7f31ad52902057ae8d8f88c38

net/openvswitch/README.md

@@ -73,10 +73,11 @@ The ovs_bridge section also supports the options below,
 for initialising a virtual bridge with an OpenFlow controller.
 
 | Name        | Type    | Required | Default                        | Description                                                |
-|------------|---------|----------|--------------------------------|------------------------------------------------------------|
+|-------------|---------|----------|--------------------------------|------------------------------------------------------------|
 | disabled    | boolean | no       | 0                              | If set to true, disable initialisation of the named bridge |
 | name        | string  | no       | Inherits UCI config block name | The name of the switch in the OVS daemon                   |
 | controller  | string  | no       | (none)                         | The endpoint of an OpenFlow controller for this bridge     |
+| datapath_id | string  | no       | (none)                         | The OpenFlow datapath ID for this bridge                   |
 
 The ovs_port section can be used to add ports to a bridge. It supports the options below.
 

net/openvswitch/files/openvswitch.config

@@ -11,6 +11,7 @@ config ovs_bridge
 	option disabled 1
 	option name 'my-bridge'
 	option controller 'tcp:192.168.0.1'
+	option datapath_id ''
 
 config ovs_port
 	option disabled 1

net/openvswitch/files/openvswitch.init

@@ -171,12 +171,26 @@ ovs_bridge_port_cleanup() {
 	done
 }
 
+ovs_bridge_validate_datapath_id() {
+	local dpid="$1"
+
+	if expr "$dpid" : '[[:xdigit:]]\{16\}$' > /dev/null; then
+		return 0
+	elif expr "$dpid" : '0x[[:xdigit:]]\{1,16\}$' > /dev/null; then
+		return 0
+	else
+		logger -t openvswitch "invalid datapath_id: $dpid"
+		return 1
+	fi
+}
+
 ovs_bridge_init() {
 	local cfg="$1"
 
 	local disabled
 	local name
 	local controller
+	local datapath_id
 
 	config_get_bool disabled "$cfg" disabled 0
 	[ "$disabled" == "0" ] || return
@@ -184,6 +198,13 @@ ovs_bridge_init() {
 	config_get name "$cfg" name $cfg
 	ovs-vsctl --may-exist add-br "$name"
 
+	config_get datapath_id "$cfg" datapath_id
+	[ -n "$datapath_id" ] && {
+		ovs_bridge_validate_datapath_id "$datapath_id" && {
+			ovs-vsctl --if-exists set bridge "$name" other-config:datapath-id="$datapath_id"
+		}
+	}
+
 	config_list_foreach "$cfg" "ports" ovs_bridge_port_add
 	config_foreach ovs_bridge_port_add_complex ovs_port "$name"
 	config_get_bool drop "$cfg" "drop_unknown_ports" 0