Re: per-FIB socket binding

On Monday, December 23, 2024 7:23:35 PM UTC Bjoern A. Zeeb wrote:
> On Sat, 21 Dec 2024, Bjoern A. Zeeb wrote:
> >> Any thoughts/comments?
> > 
> > That all said with your opt-in approach if the code itself doesn't bring
> > too many new complications I'd be happy with it (assuming FIBs still
> > have a use case).
> 
> Seems there's plenty people using multi-FIB in various scenarios still,
> which is good to know.
> 
> Go for it.

i've been thinking along these lines for a few years now, since my vm server is multi-fib. 
each interface has a fib, mostly zero. for incoming TCP SYNs, i'd like to carry that fib# into 
the resulting PCB so that that fib's routing table and especially its default route will be 
used for that connection. yes, i can do that with ipfw, and am in fact doing so now. 
however, that's crocky. i think defaulting to the interface FIB for connections created and 
maintained by the kernel should always happen -- not opt-in, not opt-out, just always. is 
it worth me sending a patch that does this or would it be considered controversial?

(making this happen for UDP is also interesting but is a separate matter since those 
servers already have to maintain socket-per-interface in order to get their source 
addresses to match the client's destination address.)

-- 
Paul Vixie