FS#4087 - Cannot use vlan 1 tagged with DSA in WRT1900ACS v2

[openwrt-bot]

luizluca:

Hello,

No matter what I change, I cannot create a wan.1 interface. Any other vlan id works:

config device
option name 'br-lan'
option type 'bridge'
list ports 'lan1'
list ports 'lan2'
list ports 'lan3'
list ports 'lan4'

config interface 'lan'
option device 'br-lan'
option proto 'static'
option netmask '255.255.255.0'
option ip6assign '60'
option ipaddr '192.168.1.4'
option gateway '192.168.1.1'

config interface 'lan6'
option proto 'dhcpv6'
option device 'br-lan'
option reqaddress 'try'
option reqprefix 'auto'

config device
option name 'br-guest'
option type 'bridge'
list ports 'wan.3'

config interface 'guest'
option proto 'none'
option device 'br-guest'

config device
option type '8021q'
option ifname 'wan'
option vid '3'
option name 'wan.3'

config device
option type '8021q'
option ifname 'wan'
option vid '2'
option name 'wan.2'

config interface 'test'
option proto 'none'
option device 'wan.1'

config device
option type '8021q'
option ifname 'wan'
option vid '1'
option name 'wan.1'

I want to add wan.1 to br-lan but the virtual device (wan.1) is never created. I created a test interface just to try to bring it up alone, but nothing made wan.1 appears.

I also tried ip-full and it also failed:

root@ap4:/etc/config# ip link add link wan name wan.1 type vlan id 2
root@ap4:/etc/config# ip link add link wan name wan.1 type vlan id 1
RTNETLINK answers: Not supported

Why vlan 1 is prohibit?

[luizluca]

#9530 did solve part of this issue. However, I still cannot add the wan.1 interface if any untagged port is added to a bridge. It might still be considering them as vlan 1.

# ip link add link wan name wan.1 type vlan id 1
[  707.030709] mv88e6085 f1072004.mdio-mii:00: p4: hw VLAN 1 already used by port 1 in br-lan

If I remove all lan ports from br-lan, I can create wan.1. However, netifd still does not take from there and wan.1 is left untouched, not included to br-lan on reload.

There is a hack that can workaround it. First I add the wan.1 before any network is up (abusing uci-defaults).

/etc/uci-defaults/hack-wan.1.sh:
#!/bin/sh
ip link add link wan name wan.1 type vlan id 1
ip link set dev wan.1 up
# Do not remove this!
exit 1

And I manually add wan.1 to br-lan on ifup.

/etc/hotplug.d/iface/30-hack-lan_wan.1:
#!/bin/sh
[ "$ACTION" = ifup -o "$ACTION" = ifupdate ] || exit 0
[ "$INTERFACE" = lan ] || exit 0
logger -t 'HACK: manually add wan.1 to br-lan'
brctl addif br-lan wan.1