UDP catchall

[Brooks Davis]

On Sat, Oct 27, 2007 at 04:21:23AM +0100, Bruce M. Simpson wrote:
>  Matus Harvan wrote:
> > Hi,
> >
> > I was wondering if I could get some feedback about the patch and
> > whether others think it could be committed.
> >   
> 
>  The UDP catchall patch as submitted here clashes with the blackhole 
>  functionality, and also bypasses the update of the protocol statistics and 
>  unreachable port rate limiting. It is not yet suitable for a production 
>  kernel.
> 
>  It probably shouldn't trigger the log_in_vain message, however that log 
>  message is misleading anyway (the reception of UDP datagrams destined for 
>  unbound ports is not a 'connection attempt').
> 
>  I would argue that the UDP and TCP catchall feature should perhaps have a 
>  configurable port range as well, under 
>  net.inet.ip.portrange.relayhigh/relaylow. This would allow the inpcb code to 
>  avoid allocating sockets from that range at all -- as well as allowing 
>  inbound packets for that range to be immediately relayed to mtund without 
>  the cost of a hash lookup.

While I think this idea has some merit, I think we specifically want
the current wildcard ability to allow for a system that requires
minimal configuration.  The problem with a range is that it doesn't
allow disjoint sets and it requires that if you really do want all the
ports you need to produce a list of currently allocated ports to avoid
allocating.  A more (over)engineered solution holds some attraction, but
I'm not yet convinced the fact that it could exist precludes the current
implementation.

-- Brooks
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