Index: bpf.c
===================================================================
RCS file: /home/ncvs/src/sys/net/bpf.c,v
retrieving revision 1.180
diff -u -p -r1.180 bpf.c
--- bpf.c	6 Aug 2007 14:26:00 -0000	1.180
+++ bpf.c	28 Aug 2007 01:34:27 -0000
@@ -599,6 +599,7 @@ bpfwrite(struct cdev *dev, struct uio *u
 	struct ifnet *ifp;
 	struct mbuf *m, *mc;
 	struct sockaddr dst;
+	struct ether_header *eh;
 	int error, hlen;
 
 	if (d->bd_bif == NULL)
@@ -620,6 +621,20 @@ bpfwrite(struct cdev *dev, struct uio *u
 	if (error)
 		return (error);
 
+	/* Check for multicast destination */
+	switch (d->bd_bif->bif_dlt) {
+	case DLT_EN10MB:
+		eh = mtod(m, struct ether_header *);
+		if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
+			if (bcmp(ifp->if_broadcastaddr, eh->ether_dhost,
+			    ETHER_ADDR_LEN) == 0)
+				m->m_flags |= M_BCAST;
+			else
+				m->m_flags |= M_MCAST;
+		}
+		break;
+	}
+
 	if (d->bd_hdrcmplt)
 		dst.sa_family = pseudo_AF_HDRCMPLT;