Annotate why we do not call BPF_CHECK_DIRECTION() in this tapping routine.

There is no way for the caller to tell us which direction this packet is
going.  With the bpf_mtap{2} routines, we can check the interface pointer.

MFC after:	2 weeks

1 files changed, 6 insertions, 0 deletions

diff --git a/sys/net/bpf.c b/sys/net/bpf.c
index e11b3e0..f9f3b7d 100644
--- a/sys/net/bpf.c
+++ b/sys/net/bpf.c
@@ -1583,6 +1583,12 @@ bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
 	LIST_FOREACH(d, &bp->bif_dlist, bd_next) {
 		BPFD_LOCK(d);
 		++d->bd_rcount;
+		/*
+		 * NB: We dont call BPF_CHECK_DIRECTION() here since there is no
+		 * way for the caller to indiciate to us whether this packet
+		 * is inbound or outbound.  In the bpf_mtap() routines, we use
+		 * the interface pointers on the mbuf to figure it out.
+		 */
 #ifdef BPF_JITTER
 		if (bpf_jitter_enable != 0 && d->bd_bfilter != NULL)
 			slen = (*(d->bd_bfilter->func))(pkt, pktlen, pktlen);