libbsd VLAN tagging

[Chris Johns]

On 22/4/20 7:52 pm, Christian Mauderer wrote:
> On 22/04/2020 09:47, Matthew J Fletcher wrote:
>> Hi,
>>
>> How would an application using libbsd add VLAN tags to transmitted
>> frames so an external switch chip could process them ?
>>
>> Is there an application / libbsd interface for this or does it require
>> the driver to be modified.
> 
> Hello Matthew,
> 
> in theory it should be the same interface like on FreeBSD:
> 
> https://www.freebsd.org/doc/handbook/network-vlan.html
> 
> But as far as I know it needs driver support:
> 
> https://www.freebsd.org/cgi/man.cgi?query=vlan&sektion=4&manpath=freebsd-release-ports
> 

Running `ifconfig` on a board running libbsd reports what the driver 
supports. For a Zynq I get ...

  # ifconfig
cgem0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 
1500 
options=68008b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6>
         ether 70:b3:d5:c1:60:29
         hwaddr 0e:b0:ba:5e:ba:11
         inet6 fe80::72b3:d5ff:fec1:6029%cgem0 prefixlen 64 scopeid 0x1
         inet 10.10.5.189 netmask 0xffffff00 broadcast 10.10.5.255
         nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
         media: Ethernet autoselect (1000baseT <full-duplex>)
         status: active

Note, `VLAN` is listed in the options so it is supported and enabled and 
you can configure support using `rc.conf`. This documented in link 
Christian provided above.

Chris