[altq 1237] Re: ALTQ conditioners on OpenBSD bridges

[Rémi Guyomarch <rguyom@pobox.com>]

On Sat, Dec 08, 2001 at 12:19:21AM -0500, Jason Wright wrote:
> On Sat, Dec 08, 2001 at 12:54:56AM +0100, Rémi Guyomarch wrote:
...
> > +#ifdef ALTQ
> > +       if (altq_input != NULL && dir == BRIDGE_IN) {
> > +               if ((*altq_input)(m, AF_INET) == 0)
> > +                       /* packet is dropped by traffic conditioner */
> > +                       goto dropit;
> > +               ip->ip_sum = 0;
> > +               ip->ip_sum = in_cksum(m, hlen);
> > +       }
> > +#endif /* ALTQ */
> > +
> 
> Ok, my question here is: is the header checksum recomputation necessary?

A conditioner either change the packet TOS according to some rules or
drop it. In the first case it's necessary to recompute the checksum.

> Also, altq treats the input mbuf as readonly correct? (No destructive
> operations, including m_pullup(), are used).

I think so, but I will let ALTQ hackers tell us the truth :)

-- 
Rémi