Function igmp_input_v1_report

freebsd/netinet/igmp.c:1258–1360

* Process a received IGMPv1 host membership report. * * NOTE: 0.0.0.0 workaround breaks const correctness. */

 * NOTE: 0.0.0.0 workaround breaks const correctness.
 */
static int
igmp_input_v1_report(struct ifnet *ifp, /*const*/ struct ip *ip,
    /*const*/ struct igmp *igmp)
{
	struct rm_priotracker in_ifa_tracker;
	struct in_ifaddr *ia;
	struct in_multi *inm;

	IGMPSTAT_INC(igps_rcv_reports);

	if (ifp->if_flags & IFF_LOOPBACK)
		return (0);

	if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr)) ||
	    !in_hosteq(igmp->igmp_group, ip->ip_dst)) {
		IGMPSTAT_INC(igps_rcv_badreports);
		return (EINVAL);
	}

	/*
	 * RFC 3376, Section 4.2.13, 9.2, 9.3:
	 * Booting clients may use the source address 0.0.0.0. Some
	 * IGMP daemons may not know how to use IP_RECVIF to determine
	 * the interface upon which this message was received.
	 * Replace 0.0.0.0 with the subnet address if told to do so.
	 */
	if (V_igmp_recvifkludge && in_nullhost(ip->ip_src)) {
		IFP_TO_IA(ifp, ia, &in_ifa_tracker);
		if (ia != NULL)
			ip->ip_src.s_addr = htonl(ia->ia_subnet);
	}

	CTR3(KTR_IGMPV3, "process v1 report 0x%08x on ifp %p(%s)",
	     ntohl(igmp->igmp_group.s_addr), ifp, ifp->if_xname);

	/*
	 * IGMPv1 report suppression.
	 * If we are a member of this group, and our membership should be
	 * reported, stop our group timer and transition to the 'lazy' state.
	 */
	IN_MULTI_LIST_LOCK();
	inm = inm_lookup(ifp, igmp->igmp_group);
	if (inm != NULL) {
		struct igmp_ifsoftc *igi;

		igi = inm->inm_igi;
		if (igi == NULL) {
			KASSERT(igi != NULL,
			    ("%s: no igi for ifp %p", __func__, ifp));
			goto out_locked;
		}

		IGMPSTAT_INC(igps_rcv_ourreports);

		/*
		 * If we are in IGMPv3 host mode, do not allow the
		 * other host's IGMPv1 report to suppress our reports
		 * unless explicitly configured to do so.