wm(4) and VLANs

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

I have a:
wm0 at pci3 dev 3 function 0: Intel i82541PI 1000BASE-T Ethernet, rev. 5

This has 3 VLANs attached:
wm0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        
capabilities=2bf80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Tx,UDP6CSUM_Tx>
        enabled=0
        address: 00:1b:21:48:15:58
        media: Ethernet autoselect (1000baseT full-duplex)
        status: active
        inet 10.0.0.1 netmask 0xffff0000 broadcast 10.0.255.255
        inet6 fe80::21b:21ff:fe48:1558%wm0 prefixlen 64 scopeid 0x2
vlan400: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        
capabilities=2bf80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Tx,UDP6CSUM_Tx>
        enabled=0
        vlan: 400 parent: wm0
        address: 00:1b:21:48:15:58
        inet 192.168.2.254 netmask 0xffffff00 broadcast 192.168.2.255
        inet6 fe80::21b:21ff:fe48:1558%vlan400 prefixlen 64 scopeid 0x6
vlan500: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        
capabilities=2bf80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Tx,UDP6CSUM_Tx>
        enabled=0
        vlan: 500 parent: wm0
        address: 00:1b:21:48:15:58
        inet 192.168.3.254 netmask 0xffffff00 broadcast 192.168.3.255
        inet6 fe80::21b:21ff:fe48:1558%vlan500 prefixlen 64 scopeid 0x7
vlan900: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        
capabilities=2bf80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Tx,UDP6CSUM_Tx>
        enabled=0
        vlan: 900 parent: wm0
        address: 00:1b:21:48:15:58
        inet 192.168.5.1 netmask 0xffffff00 broadcast 192.168.5.255
        inet6 fe80::21b:21ff:fe48:1558%vlan900 prefixlen 64 scopeid 0x8

However, DHCP requests come on both the vlan and parent interface:
May 25 15:00:06 netmanager dhcpd: DHCPDISCOVER from d0:23:db:3b:b2:d2 via 
vlan400
May 25 15:00:06 netmanager dhcpd: DHCPOFFER on 192.168.2.196 to 
d0:23:db:3b:b2:d2 via vlan400
May 25 15:00:06 netmanager dhcpd: DHCPDISCOVER from d0:23:db:3b:b2:d2 via wm0
May 25 15:00:06 netmanager dhcpd: DHCPOFFER on 10.0.10.56 to d0:23:db:3b:b2:d2 
via wm0

It's therefore a lottery what IP range you get allocated.

Is this a bug in wm(4) for this particular chipset?

--
Stephen