Function bridge_forward

freebsd/net/if_bridge.c:2193–2331

* bridge_forward: * * The forwarding function of the bridge. * * NOTE: Releases the lock on return. */

 *	NOTE: Releases the lock on return.
 */
static void
bridge_forward(struct bridge_softc *sc, struct bridge_iflist *sbif,
    struct mbuf *m)
{
	struct bridge_iflist *dbif;
	struct ifnet *src_if, *dst_if, *ifp;
	struct ether_header *eh;
	uint16_t vlan;
	uint8_t *dst;
	int error;

	NET_EPOCH_ASSERT();

	src_if = m->m_pkthdr.rcvif;
	ifp = sc->sc_ifp;

	if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
	if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
	vlan = VLANTAGOF(m);

	if ((sbif->bif_flags & IFBIF_STP) &&
	    sbif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING)
		goto drop;

	eh = mtod(m, struct ether_header *);
	dst = eh->ether_dhost;

	/* If the interface is learning, record the address. */
	if (sbif->bif_flags & IFBIF_LEARNING) {
		error = bridge_rtupdate(sc, eh->ether_shost, vlan,
		    sbif, 0, IFBAF_DYNAMIC);
		/*
		 * If the interface has addresses limits then deny any source
		 * that is not in the cache.
		 */
		if (error && sbif->bif_addrmax)
			goto drop;
	}

	if ((sbif->bif_flags & IFBIF_STP) != 0 &&
	    sbif->bif_stp.bp_state == BSTP_IFSTATE_LEARNING)
		goto drop;

	/*
	 * At this point, the port either doesn't participate
	 * in spanning tree or it is in the forwarding state.
	 */

	/*
	 * If the packet is unicast, destined for someone on
	 * "this" side of the bridge, drop it.
	 */
	if ((m->m_flags & (M_BCAST|M_MCAST)) == 0) {
		dst_if = bridge_rtlookup(sc, dst, vlan);
		if (src_if == dst_if)
			goto drop;
	} else {
		/*