[Feature Request] Add GUI to use a LAN port for WAN

[hryamzik]

Found similar topic and managed to make it working on a second attempt.

On the first one I even got connection status in UI but something was terribly wrong with routing so ended up reseting device.

So far I’ve done the following:

1. Adjusted my router setup in /usr/share/gl-eth-ports.json:

    "axt1800": {
        "wan": { "port": "eth0", "silk": "WAN" },
        "secondwan": { "name": "lan2", "port": "eth1", "silk": "WAN/LAN2" },
        "lan": [
            { "name": "lan1", "port": "eth2", "silk": "LAN1" }
        ]
    },

2. Adjusted /etc/config/board_special:

config service 'hardware'
        option secondwan 'eth1'

config switch 'switch'
        option enable '0'

config network 'network'
        option wan 'eth0'
        option lan 'eth1 eth2'

3. Rebooted router, switched LAN2 to WAN mode in ui.

4. Adjusted firewall adding secondwan and secondwan6 to wan rules

5. Added missing options to secondwan in /etc/config/network

6. Added to kmwan /etc/config/kmwan

7. Rebooted.

   Multi-WAN doesn’t detect that second connection is actually active while in port management active link is detected. Otherwise it just works, luci also shows all the details.

   I believe the main difference between my previous attempt is secondwan name, I used lwan initially and status worked.