Function igmp_change_state

freebsd/netinet/igmp.c:2317–2369

* Process a state change from the upper layer for the given IPv4 group. * * Each socket holds a reference on the in_multi in its own ip_moptions. * The socket layer will have made the necessary updates to.the group * state, it is now up to IGMP to issue a state change report if there * has been any change between T0 (when the last state-change was issued) * and T1 (now). * * We use the IGM

 * is called from the socket option handlers.
 */
int
igmp_change_state(struct in_multi *inm)
{
	struct igmp_ifsoftc *igi;
	struct ifnet *ifp;
	int error;

	error = 0;
	IN_MULTI_LOCK_ASSERT();
	/*
	 * Try to detect if the upper layer just asked us to change state
	 * for an interface which has now gone away.
	 */
	KASSERT(inm->inm_ifma != NULL, ("%s: no ifma", __func__));
	ifp = inm->inm_ifma->ifma_ifp;
	/*
	 * Sanity check that netinet's notion of ifp is the
	 * same as net's.
	 */
	KASSERT(inm->inm_ifp == ifp, ("%s: bad ifp", __func__));

	IGMP_LOCK();

	igi = ((struct in_ifinfo *)ifp->if_afdata[AF_INET])->ii_igmp;
	KASSERT(igi != NULL, ("%s: no igmp_ifsoftc for ifp %p", __func__, ifp));

	/*
	 * If we detect a state transition to or from MCAST_UNDEFINED
	 * for this group, then we are starting or finishing an IGMP
	 * life cycle for this group.
	 */
	if (inm->inm_st[1].iss_fmode != inm->inm_st[0].iss_fmode) {
		CTR3(KTR_IGMPV3, "%s: inm transition %d -> %d", __func__,
		    inm->inm_st[0].iss_fmode, inm->inm_st[1].iss_fmode);
		if (inm->inm_st[0].iss_fmode == MCAST_UNDEFINED) {
			CTR1(KTR_IGMPV3, "%s: initial join", __func__);
			error = igmp_initial_join(inm, igi);
			goto out_locked;
		} else if (inm->inm_st[1].iss_fmode == MCAST_UNDEFINED) {
			CTR1(KTR_IGMPV3, "%s: final leave", __func__);
			igmp_final_leave(inm, igi);
			goto out_locked;
		}
	} else {
		CTR1(KTR_IGMPV3, "%s: filter set change", __func__);
	}

	error = igmp_handle_state_change(inm, igi);

out_locked:
	IGMP_UNLOCK();
	return (error);
}

/*
 * Perform the initial join for an IGMP group.