Function debugnet_pkt_in

freebsd/net/debugnet.c:517–575

* Handler for incoming packets directly from the network adapter * Identifies the packet type (IP or ARP) and passes it along to one of the * helper functions debugnet_handle_ip or debugnet_handle_arp. * * It needs to partially replicate the behaviour of ether_input() and * ether_demux(). * * Parameters: * ifp the interface the packet came from * m an mbuf containing the packet received

 *	m	an mbuf containing the packet received
 */
static void
debugnet_pkt_in(struct ifnet *ifp, struct mbuf *m)
{
	struct ifreq ifr;
	struct ether_header *eh;
	u_short etype;

	/* Ethernet processing. */
	if ((m->m_flags & M_PKTHDR) == 0) {
		DNETDEBUG_IF(ifp, "discard frame without packet header\n");
		goto done;
	}
	if (m->m_len < ETHER_HDR_LEN) {
		DNETDEBUG_IF(ifp,
	    "discard frame without leading eth header (len %u pktlen %u)\n",
		    m->m_len, m->m_pkthdr.len);
		goto done;
	}
	if ((m->m_flags & M_HASFCS) != 0) {
		m_adj(m, -ETHER_CRC_LEN);
		m->m_flags &= ~M_HASFCS;
	}
	eh = mtod(m, struct ether_header *);
	etype = ntohs(eh->ether_type);
	if ((m->m_flags & M_VLANTAG) != 0 || etype == ETHERTYPE_VLAN) {
		DNETDEBUG_IF(ifp, "ignoring vlan packets\n");
		goto done;
	}
	if (if_gethwaddr(ifp, &ifr) != 0) {
		DNETDEBUG_IF(ifp, "failed to get hw addr for interface\n");
		goto done;
	}
	if (memcmp(ifr.ifr_addr.sa_data, eh->ether_dhost,
	    ETHER_ADDR_LEN) != 0 &&
	    (etype != ETHERTYPE_ARP || !ETHER_IS_BROADCAST(eh->ether_dhost))) {
		DNETDEBUG_IF(ifp,
		    "discard frame with incorrect destination addr\n");
		goto done;
	}

	MPASS(g_debugnet_pcb_inuse);

	/* Done ethernet processing. Strip off the ethernet header. */
	m_adj(m, ETHER_HDR_LEN);
	switch (etype) {
	case ETHERTYPE_ARP:
		debugnet_handle_arp(&g_dnet_pcb, &m);
		break;
	case ETHERTYPE_IP:
		debugnet_handle_ip(&g_dnet_pcb, &m);
		break;
	default:
		DNETDEBUG_IF(ifp, "dropping unknown ethertype %hu\n", etype);
		break;
	}
done:
	if (m != NULL)
		m_freem(m);