net/mwan3: add online_metric for local_source none

If we set the option "local_source" in the globals mwan3 section to "none",
traffic generated by the router it self will always use the default route from
the wan interface with the lowest metric. If this interface is down
the router traffic still uses the connection with the lowest metric but
this is disconnected. Load balancing and failover from the lan site is
still possible. Only router generated traffic is not load balanced and
could not use failover.

To solve this issue with router initiated traffic add the additional
option "online_metric" to the mwan3 interface section.

If the interface is connected then this lower "online metric" is set in the
default routing table.

With this change we have at least a failover with router initiated
traffic.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

net/mwan3/files/etc/hotplug.d/iface/13-mwan3

@@ -0,0 +1,98 @@
+#!/bin/sh
+
+. /lib/functions.sh
+. /lib/functions/network.sh
+. /lib/mwan3/mwan3.sh
+
+LOG="logger -t mwan3[$$] -p"
+
+[ "$ACTION" = "connected" -o "$ACTION" = "disconnected" ] || exit 1
+[ -n "$INTERFACE" ] || exit 2
+
+if [ "$ACTION" = "connected" ]; then
+	[ -n "$DEVICE" ] || exit 3
+fi
+
+config_load mwan3
+config_get_bool enabled globals 'enabled' '0'
+config_get local_source globals 'local_source' 'none'
+[ ${enabled} = "1" ] || exit 0
+[ ${local_source} = "none" ] || exit 0
+
+config_get enabled $INTERFACE enabled 0
+config_get online_metric $INTERFACE online_metric 0
+[ "$enabled" == "1" ] || exit 0
+
+if [ "$online_metric" = 0 ]; then
+	$LOG notice "No online metric for interface "$INTERFACE" found"
+	exit 0
+fi
+
+mwan3_add_failover_metric() {
+	local iface="$1"
+	local device="$2"
+	local metric="$3"
+
+	local route_args
+
+	config_get family $iface family ipv4
+
+	if [ "$family" == "ipv4" ]; then
+		if ubus call network.interface.${iface}_4 status 1>/dev/null 2>&1; then
+			network_get_gateway route_args ${iface}_4
+		else
+			network_get_gateway route_args $iface
+		fi
+
+		if [ -n "$route_args" -a "$route_args" != "0.0.0.0" ]; then
+			route_args="via $route_args"
+		else
+			route_args=""
+		fi
+
+		$IP4 route add default $route_args dev $device proto static metric $metric 1>/dev/null 2>&1
+	fi
+
+	if [ "$family" == "ipv6" ]; then
+		if ubus call network.interface.${iface}_6 status 1>/dev/null 2>&1; then
+			network_get_gateway6 route_args ${iface}_6
+		else
+			network_get_gateway6 route_args $iface
+		fi
+
+		if [ -n "$route_args" -a "$route_args" != "::" ]; then
+			route_args="via $route_args"
+		else
+			route_args=""
+		fi
+
+		$IP6 route add default $route_args dev $device proto static metric $metric 1>/dev/null 2>&1
+	fi
+}
+
+mwan3_del_failover_metric() {
+	local iface="$1"
+	local device="$2"
+	local metric="$3"
+
+	config_get family $iface family ipv4
+
+	if [ "$family" == "ipv4" ]; then
+		$IP4 route del default dev $device proto static metric $metric 1>/dev/null 2>&1
+	fi
+
+	if [ "$family" == "ipv6" ]; then
+		$IP6 route del default dev $device proto static metric $metric 1>/dev/null 2>&1
+	fi
+}
+
+case "$ACTION" in
+	connected)
+		mwan3_add_failover_metric "$INTERFACE" "$DEVICE" "$online_metric"
+		;;
+	disconnected)
+		mwan3_del_failover_metric "$INTERFACE" "$DEVICE" "$online_metric"
+		;;
+esac
+
+exit 0

net/mwan3/files/lib/mwan3/mwan3.sh

@@ -1219,3 +1219,25 @@ mwan3_track_clean()
 		fi
 	}
 }
+
+mwan3_online_metric_clean() {
+	local iface="$1"
+
+	local online_metric ifname
+
+	config_get family $iface family ipv4
+	config_get online_metric $iface online_metric ""
+	ifname=$(uci_get_state network $iface ifname)
+
+	if [ "$family" == "ipv4" ] \
+		&& [ "$online_metric" != "" ] \
+		&& [ "$ifname" != "" ]; then
+		$IP4 route del default dev $ifname proto static metric $online_metric 1>/dev/null 2>&1
+	fi
+
+	if [ "$family" == "ipv6" ] \
+		&& [ "$online_metric" != "" ] \
+		&& [ "$ifname" != "" ]; then
+		$IP6 route del default dev $ifname proto static metric $online_metric 1>/dev/null 2>&1
+	fi
+}

net/mwan3/files/usr/sbin/mwan3

@@ -175,6 +175,7 @@ stop()
 
 	config_load mwan3
 	config_foreach mwan3_track_clean interface
+	config_foreach mwan3_online_metric_clean interface
 
 	for IP in "$IP4" "$IP6"; do