Subject: Re: divert socket?
To: None <tech-kern@netbsd.org>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: tech-kern
Date: 10/24/2001 20:10:33
On Thu, Oct 25, 2001 at 09:41:39AM +1000, Darren Reed wrote:
> In some email I received from Perry E. Metzger, sie wrote:
> > 
> > Darren Reed <darrenr@reed.wattle.id.au> writes:
> > > > I don't know about divert sockets, but I see two alternatives:
> > > > 1) the standard bpf interface  as used e.g. by IDS systems like
> > > >    snort (it's in pkgsrc)
> > > 
> > > divert isn't as lossy as bpf is.
> > 
> > Er, at some point any such mechanism will fill its queues. It is just
> > a question of policy. If you need more buffering because of transient
> > scheduling issues, you can increase the size of the buffering bpf has
> > available. If you can't process the packets as fast as they appear, no
> > amount of buffering will help.
> > 
> > Remember, btw, the network itself is lossy.
> > 
> > To my mind, bpf is sufficient. Hell, NFR uses it and that's the best IDS
> > I know.
> 
> NFR does not use the same version of BPF as we do.  They optimized it.
> Can ours be optimized ?  Yes but tcpdump.org doesn't seem too interested.

We ought to pick up the NFR optimizations.  Really, we should have done so 
when they initially wrote them.

-- 
Thor Lancelot Simon	                                      tls@rek.tjls.com
    And now he couldn't remember when this passion had flown, leaving him so
  foolish and bewildered and astray: can any man?
						   William Styron