Only send packet to bpf if we are committed to send it. Previously it was

possible that the same packet would show up multiple times.  This poses some
constraints on the TBD locking for snc(4) (see comment).

Obtained from:	DragonFlyBSD
Submitted by:	Joerg Sonnenberger
Reviewed by:	rwatson

1 files changed, 10 insertions, 6 deletions

diff --git a/sys/dev/snc/dp83932.c b/sys/dev/snc/dp83932.c
index 1ffd4f15cd9c..90806990ac8a 100644
--- a/sys/dev/snc/dp83932.c
+++ b/sys/dev/snc/dp83932.c
@@ -346,12 +346,6 @@ outloop:
 	M_ASSERTPKTHDR(m);
 
 	/*
-	 * If bpf is listening on this interface, let it
-	 * see the packet before we commit it to the wire.
-	 */
-	BPF_MTAP(ifp, m);
-
-	/*
 	 * If there is nothing in the o/p queue, and there is room in
 	 * the Tx ring, then send the packet directly.  Otherwise append
 	 * it to the o/p queue.
@@ -361,6 +355,16 @@ outloop:
 		return;
 	}
 
+	/*
+	 * If bpf is listening on this interface, let it see the packet
+	 * before we commit it to the wire, but only if we are really
+	 * committed to send it.
+	 *
+	 * XXX: Locking must protect m against premature m_freem() in
+	 * sonictxint().
+	 */
+	BPF_MTAP(ifp, m);
+
 	sc->mtd_prev = sc->mtd_free;
 	sc->mtd_free = mtd_next;