qos-scripts: Allow classification by the traffic's source interface

This adds a "srciface" option that can be used on classification
rules in /etc/config/qos.  This is useful to allow prioritization
based on the local network from which the traffic originates, for
example to deprioritize traffic from a guest network.

Signed-off-by: Michael Marley <michael@michaelmarley.com>

SVN-Revision: 48446

package/network/config/qos-scripts/files/usr/lib/qos/generate.sh

@@ -141,6 +141,9 @@ parse_matching_rule() {
 					append "$var" "-i $device"
 				fi
 			;;
+			*:srciface)
+				append "$var" "-i $value"
+			;;
 			1:pktsize)
 				value="$(echo "$value" | sed -e 's,-,:,g')"
 				add_insmod xt_length