Re: link-state change for virtual interfaces

[Rin Okuyama <rokuyama.rk%gmail.com@localhost>]

On 2024/09/25 20:08, Valery Ushakov wrote:
> On Wed, Sep 25, 2024 at 10:32:18 +0900, Rin Okuyama wrote:
>
> > Recently, link-state emulation has been added to shmif(4) and
> > vether(4). Unfortunately, different operations are required for
> > link-up/down for these interfaces:
> >
> > For shmif(4)
> > - link-up:   ifconfig shmif%d media auto
> > - link-down: ifconfig shmif%d media none
> >
> > https://mail-index.netbsd.org/source-changes/2024/08/20/msg152934.html
> > https://mail-index.netbsd.org/source-changes/2024/08/20/msg152935.html
> >
> > For vether(4)
> > - link-up:   ifconfig vether%d link1
> > - link-down: ifconfig vether%d -link1
> >
> > https://mail-index.netbsd.org/source-changes/2024/09/24/msg153517.html
> > https://mail-index.netbsd.org/source-changes/2024/09/24/msg153525.html
> >
> > Wouldn't it be better to unify as far as possible? If so,
> > which one is more preferable? (The 3rd candidate may be
> > to add dedicated flag bit, but it seems too much to me.)
>
> "Pluggin" and "unplugging" the media, like shmif does, seems like an
> interesting metaphor.  How is it reflected in ifconfig output?
> I.e. what does
>
>    $ ifconfig $shmif
>
> show for "media: ..." in both states?

Yeah, interesting :) Here's ifconfig output:

````
# rump.ifconfig shmif0 media auto
# rump.ifconfig shmif0
shmif0: flags=0x8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
  capabilities=0x7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
  capabilities=0x7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
  capabilities=0x7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
  enabled=0
  address: b2:a0:01:9d:82:a5
  linkstr: bus1
  media: Ethernet autoselect
# rump.ifconfig shmif0 media none
# rump.ifconfig shmif0
shmif0: flags=0x8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
  capabilities=0x7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
  capabilities=0x7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
  capabilities=0x7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
  enabled=0
  address: b2:a0:6b:44:5b:bd
  linkstr: bus1
  media: Ethernet none
````

If `-v` option is specified to ifconfig,
  linkstate: up
and
  linkstate: down
appear b/w linkstr and media lines. This should happen also for vether:

https://mail-index.netbsd.org/source-changes/2024/08/20/msg152936.html

Thanks,
rin

> -uwe