Handle broadcast and multicast packets in router mode.

Multicast packets are treated as broadcast packets.
Based on a patch from Max Rijevski.

THANKS

@@ -21,6 +21,7 @@ We would like to thank the following people for their contributions to tinc:
 * Markus Goetz
 * Martin Kihlgren
 * Matias Carrasco
+* Max Rijevski
 * Miles Nordin
 * Nick Patavalis
 * Paul Littlefield

src/route.c

@@ -376,7 +376,14 @@ static void route_ipv4(node_t *source, vpn_packet_t *packet)
 	if(!checklength(source, packet, ether_size + ip_size))
 		return;
 
-	route_ipv4_unicast(source, packet);
+	if(packet->data[30] & 0xf0 == 0xe0 ||
+			packet->data[30] == 255 &&
+			packet->data[31] == 255 &&
+			packet->data[32] == 255 &&
+			packet->data[33] == 255)
+		broadcast_packet(source, packet);
+	else
+		route_ipv4_unicast(source, packet);
 }
 
 /* RFC 2463 */
@@ -645,7 +652,10 @@ static void route_ipv6(node_t *source, vpn_packet_t *packet)
 		return;
 	}
 
-	route_ipv6_unicast(source, packet);
+	if(packet->data[38] == 255)
+		broadcast_packet(source, packet);
+	else
+		route_ipv6_unicast(source, packet);
 }
 
 /* RFC 826 */