Function bridge_output

freebsd/net/if_bridge.c:2047–2147

* bridge_output: * * Send output from a bridge member interface. This * performs the bridging function for locally originated * packets. * * The mbuf has the Ethernet header already attached. We must * enqueue or free the mbuf before returning. */

 *	enqueue or free the mbuf before returning.
 */
static int
bridge_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
    struct rtentry *rt)
{
	struct ether_header *eh;
	struct ifnet *bifp, *dst_if;
	struct bridge_softc *sc;
	uint16_t vlan;

	NET_EPOCH_ASSERT();

	if (m->m_len < ETHER_HDR_LEN) {
		m = m_pullup(m, ETHER_HDR_LEN);
		if (m == NULL)
			return (0);
	}

	eh = mtod(m, struct ether_header *);
	sc = ifp->if_bridge;
	vlan = VLANTAGOF(m);

	bifp = sc->sc_ifp;

	/*
	 * If bridge is down, but the original output interface is up,
	 * go ahead and send out that interface.  Otherwise, the packet
	 * is dropped below.
	 */
	if ((bifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
		dst_if = ifp;
		goto sendunicast;
	}

	/*
	 * If the packet is a multicast, or we don't know a better way to
	 * get there, send to all interfaces.
	 */
	if (ETHER_IS_MULTICAST(eh->ether_dhost))
		dst_if = NULL;
	else
		dst_if = bridge_rtlookup(sc, eh->ether_dhost, vlan);
	/* Tap any traffic not passing back out the originating interface */
	if (dst_if != ifp)
		ETHER_BPF_MTAP(bifp, m);
	if (dst_if == NULL) {
		struct bridge_iflist *bif;
		struct mbuf *mc;
		int used = 0;

		bridge_span(sc, m);

		CK_LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
			dst_if = bif->bif_ifp;

			if (dst_if->if_type == IFT_GIF)
				continue;
			if ((dst_if->if_drv_flags & IFF_DRV_RUNNING) == 0)
				continue;