Date: Wed, 31 Aug 2005 15:59:45 -0400 From: Ed Maste <emaste@phaedrus.sandvine.ca> To: freebsd-net@freebsd.org Subject: BIOCSSEESENT ioctl not honoured for single-mbuf packets Message-ID: <20050831195945.GA22805@sandvine.com>
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A coworker of mine discovered a bug in bpf with BIOCSEESENT.
In sys/net/bpf.c, bpf_mtap() does
if (pktlen == m->m_len) {
bpf_tap(bp, mtod(m, u_char *), pktlen);
return;
}
BPFIF_LOCK(bp);
LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL))
continue;
[...]
The pktlen == m->m_len is an optimization for the case where
the entire packet is in a single mbuf, added in version 1.95.
However, bd_seesent then isn't checked so all packets will be
seen.
In order to make bpf_tap work correctly with BIOCSEESENT for
both this case and the few drivers that use it, I think it needs
another argument to indicate if the packet is being sent or not.
Is it possible to change the API for bpf_tap? Or add a bpf_tap2
that includes the flag, and make bpf_tap call it (for any third
party drivers using bpf_tap)?
--
Ed Maste
Sandvine Incorporated
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