Subject: Re: use of m_pkthdr.rcvif by ipsec outbound processing.
To: None <firstname.lastname@example.org>
From: Bill Sommerfeld <email@example.com>
Date: 10/12/1999 17:46:39
> I totally agree that it is cleaner to add field to struct mbuf,
> however, I really hesitate to add member into mbuf, as in many
> case the usable data size in mbuf matters. on architectures
> with sizeof(void *) == 4, MHLEN will be 100 and this captures
> short packets, which are commonly used in tcp ack and others.
> We may want to increase MSIZE into 256 (even on non-64bit arch) if
> we need to add more fields.
If size is a concern, how about using a union and a flag bit?
(if the flag is clear, use the rcvif arm of the union; if set, use the
sndso arm of the union).
One other note.. it occurs to me that a complete policy engine may
also want to know the receiving interface for forwarded packets, so
keeping the old value around might make sense.