Fix packet flow when both ng_ether(4) and bridge(4) are in use:

- push all bridge logic from if_ethersubr.c into bridge.c
  make bridge_in() return mbuf pointer (or NULL).
- call only bridge_in() from ether_input(), after ng_ether_input()
  was optinally called.
- call bridge_in() from ng_ether_rcv_upper().

Long description:	http://lists.freebsd.org/mailman/htdig/freebsd-net/2004-May/003881.html
Reported by:		Jian-Wei Wang <jwwang at FreeBSD.csie.NCTU.edu.tw>
Tested by:		myself, Sergey Lyubka
Reviewed by:		sam
Approved by:		julian (mentor)
MFC after:		2 months

3 files changed, 32 insertions, 51 deletions

diff --git a/sys/net/bridge.c b/sys/net/bridge.c
index 75f7c30..ddd0f0b 100644
--- a/sys/net/bridge.c
+++ b/sys/net/bridge.c
@@ -240,6 +240,7 @@ SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, fw_count, CTLFLAG_RW,
 
 static int bdginit(void);
 static void parse_bdg_cfg(void);
+static struct mbuf *bdg_forward(struct mbuf *, struct ifnet *);
 
 static int bdg_ipf;		/* IPFilter enabled in bridge */
 SYSCTL_INT(_net_link_ether_bridge, OID_AUTO, ipf, CTLFLAG_RW,
@@ -760,13 +761,16 @@ bridge_dst_lookup(struct ether_header *eh, struct cluster_softc *c)
  * to fetch more of the packet, or simply drop it completely.
  */
 
-static struct ifnet *
-bridge_in(struct ifnet *ifp, struct ether_header *eh)
+static struct mbuf *
+bridge_in(struct ifnet *ifp, struct mbuf *m)
 {
-    int index;
+    struct ether_header *eh;
     struct ifnet *dst, *old;
     bdg_hash_table *bt;			/* location in hash table */
     int dropit = BDG_MUTED(ifp);
+    int index;
+
+    eh = mtod(m, struct ether_header *);
 
     /*
      * hash the source address
@@ -856,7 +860,28 @@ bridge_in(struct ifnet *ifp, struct ether_header *eh)
 	(dst <= BDG_FORWARD) ? bdg_dst_names[(uintptr_t)dst] :
 		dst->if_xname));
 
-    return dst;
+    switch ((uintptr_t)dst) {
+    case (uintptr_t)BDG_DROP:
+	m_freem(m);
+	return (NULL);
+    case (uintptr_t)BDG_LOCAL:
+	return (m);
+    case (uintptr_t)BDG_BCAST:
+    case (uintptr_t)BDG_MCAST:
+        m = bdg_forward(m, dst);
+#ifdef	DIAGNOSTIC	/* glebius: am I right here? */
+	if (m == NULL) {
+		if_printf(ifp, "bridge dropped %s packet\n",
+		     dst == BDG_BCAST ? "broadcast" : "multicast");
+		return (NULL);
+	}
+#endif
+	return (m);
+    default:
+        m = bdg_forward(m, dst);
+    }
+
+    return (NULL); /* not reached */
 }
 
 /*
diff --git a/sys/net/bridge.h b/sys/net/bridge.h
index de30210..666c65d 100644
--- a/sys/net/bridge.h
+++ b/sys/net/bridge.h
@@ -101,7 +101,7 @@ struct bdg_stats {
 #define BDG_STAT(ifp, type) bdg_stats.s[ifp->if_index].p_in[(uintptr_t)type]++ 
  
 #ifdef _KERNEL
-typedef	struct ifnet *bridge_in_t(struct ifnet *, struct ether_header *);
+typedef	struct mbuf *bridge_in_t(struct ifnet *, struct mbuf *);
 /* bdg_forward frees the mbuf if necessary, returning null */
 typedef	struct mbuf *bdg_forward_t(struct mbuf *, struct ifnet *);
 typedef	void bdgtakeifaces_t(void);
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 2a5a030..e7a923b 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -566,53 +566,9 @@ ether_input(struct ifnet *ifp, struct mbuf *m)
 	}
 
 	/* Check for bridging mode */
-	if (BDG_ACTIVE(ifp) ) {
-		struct ifnet *bif;
-
-		/*
-		 * Check with bridging code to see how the packet
-		 * should be handled.  Possibilities are:
-		 *
-		 *    BDG_BCAST		broadcast
-		 *    BDG_MCAST		multicast
-		 *    BDG_LOCAL		for local address, don't forward
-		 *    BDG_DROP		discard
-		 *    ifp		forward only to specified interface(s)
-		 *
-		 * Non-local destinations are handled by passing the
-		 * packet back to the bridge code.
-		 */
-		bif = bridge_in_ptr(ifp, eh);
-		if (bif == BDG_DROP) {		/* discard packet */
-			m_freem(m);
+	if (BDG_ACTIVE(ifp) )
+		if ((m = bridge_in_ptr(ifp, m)) == NULL)
 			return;
-		}
-		if (bif != BDG_LOCAL) {		/* non-local, forward */
-			m = bdg_forward_ptr(m, bif);
-			/*
-			 * The bridge may consume the packet if it's not
-			 * supposed to be passed up or if a problem occurred
-			 * while doing its job.  This is reflected by it
-			 * returning a NULL mbuf pointer.
-			 */
-			if (m == NULL) {
-				if (bif == BDG_BCAST || bif == BDG_MCAST)
-					if_printf(ifp,
-						"bridge dropped %s packet\n",
-						bif == BDG_BCAST ? "broadcast" :
-								   "multicast");
-				return;
-			}
-			/*
-			 * But in some cases the bridge may return the
-			 * packet for us to free; sigh.
-			 */
-			if (bif != BDG_BCAST && bif != BDG_MCAST) {
-				m_freem(m);
-				return;
-			}
-		}
-	}
 
 	/* First chunk of an mbuf contains good entropy */
 	if (harvest.ethernet)