Re: Announcing ethernet link state changes via route socket

["Vlad GALU" <dudu@xxxxxxx>]

On 3/16/07, Hasso Tepper <hasso@estpak.ee> wrote:
> Announcing link state changes to the userspace via route socket is critical
> to get routing related applications to work correctly - routing protocols
> are most important, but other applications might benefit from it as well.
>
> This code is adapted from OpenBSD and is only the first basic step in path
> to get correct support. Only em(4) is tested because I don't have hardware
> to test others, although bge(4) might get my attention as well in the
> future.
>
> There is one fundamental problem I'd like to get feedback about from
> developers - how to make various kernel stuff react on link state changes?

  There's been an IRC conversation recently regarding that. FreeBSD
defines a EVFILT_NETDEV filter, which can have one of the following
event bits set: NOTE_LINKUP, NOTE_LINKDOWN, NOTE_LINKINV. It's a quite
clean interface. I don't know why OpenBSD chose to do it diferently.

> For example various interfaces which are somehow attached to the interface
> (bridges, carp, vlans etc) should react. Ideally routing table should react
> as well (yes, no BSD or Linux kernel does that yet, but they should).
> Personally I like the idea of the hooks OpenBSD uses, but as I'm not very
> familiar of DragonFlyBSD, my personal opinion might be very far from good
> solution ;).
>
>
> regards,
>
> --
> Hasso Tepper


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