bcm53xx: set WAN MAC address to don't share one with LAN interface

After analyzing numerous NVRAMs and vendor firmwares it seems the base
MAC address is used for LAN interface. WAN interface has different one
which sometimes is set directly in NVRAM and sometines needs to be
calculated.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

target/linux/bcm53xx/base-files/etc/board.d/02_network

@@ -25,22 +25,28 @@ buffalo,wzr-1750dhp)
 	;;
 esac
 
+wan_macaddr="$(nvram get wan_hwaddr)"
 case "$board" in
 asus,rt-ac87u)
 	ifname=eth1
+	etXmacaddr=$(nvram get et1macaddr)
 	;;
 dlink,dir-885l | \
 netgear,r7900 | \
 netgear,r8000 | \
 netgear,r8500)
-
 	ifname=eth2
+	etXmacaddr=$(nvram get et2macaddr)
 	;;
 *)
 	ifname=eth0
+	etXmacaddr=$(nvram get et0macaddr)
 	;;
 esac
 
+# If WAN MAC isn't explicitly set, calculate it using base MAC as reference.
+[ -z "$wan_macaddr" -a -n "$etXmacaddr" ] && wan_macaddr=$(macaddr_add "$etXmacaddr" 1)
+
 # Workaround for devices using eth2 connected to (CPU) switch port 8
 case "$board" in
 dlink,dir-885l | \
@@ -55,6 +61,7 @@ netgear,r8500)
 	# assigned. Manually assign eth2's MAC to the LAN.
 	et2macaddr="$(nvram get et2macaddr)"
 	[ -n "$et2macaddr" ] && ucidef_set_interface_macaddr "lan" "$et2macaddr"
+	[ -n "$wan_macaddr" ] && ucidef_set_interface_macaddr "wan" "$wan_macaddr"
 
 	board_config_flush
 	exit 0
@@ -85,6 +92,8 @@ else
 		"0:lan" "1:lan" "2:lan" "3:lan" "4:wan" "5t@$ifname"
 fi
 
+[ -n "$wan_macaddr" ] && ucidef_set_interface_macaddr "wan" "$wan_macaddr"
+
 board_config_flush
 
 exit 0