mld6.c

来自「eCos操作系统源码」· C语言 代码 · 共 522 行 · 第 1/2 页

		if (ifp->if_flags & IFF_LOOPBACK)
			break;

		if (!IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) &&
		    !IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
			break;	/* print error or log stat? */
		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
			mldh->mld_addr.s6_addr16[1] =
				htons(ifp->if_index); /* XXX */

		/*
		 * - Start the timers in all of our membership records
		 *   that the query applies to for the interface on
		 *   which the query arrived excl. those that belong
		 *   to the "all-nodes" group (ff02::1).
		 * - Restart any timer that is already running but has
		 *   A value longer than the requested timeout.
		 * - Use the value specified in the query message as
		 *   the maximum timeout.
		 */
		IFP_TO_IA6(ifp, ia);
		if (ia == NULL)
			break;

		/*
		 * XXX: System timer resolution is too low to handle Max
		 * Response Delay, so set 1 to the internal timer even if
		 * the calculated value equals to zero when Max Response
		 * Delay is positive.
		 */
		timer = ntohs(mldh->mld_maxdelay)*PR_FASTHZ/MLD6_TIMER_SCALE;
		if (timer == 0 && mldh->mld_maxdelay)
			timer = 1;
		mld6_all_nodes_linklocal.s6_addr16[1] =
			htons(ifp->if_index); /* XXX */
		
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
		LIST_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
#else
		for (in6m = ia->ia6_multiaddrs.lh_first;
		     in6m;
		     in6m = in6m->in6m_entry.le_next)
#endif
		{
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
			if (ifma->ifma_addr->sa_family != AF_INET6)
				continue;
			in6m = (struct in6_multi *)ifma->ifma_protospec;
			if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
					&mld6_all_nodes_linklocal) ||
			    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
			    IPV6_ADDR_SCOPE_LINKLOCAL)
				continue;
#else
			if (IN6_ARE_ADDR_EQUAL(&in6m->in6m_addr,
						&mld6_all_nodes_linklocal) ||
			    IPV6_ADDR_MC_SCOPE(&in6m->in6m_addr) <
			    IPV6_ADDR_SCOPE_LINKLOCAL)
				continue;
#endif

			if (IN6_IS_ADDR_UNSPECIFIED(&mldh->mld_addr) ||
			    IN6_ARE_ADDR_EQUAL(&mldh->mld_addr,
						&in6m->in6m_addr))
			{
				if (timer == 0) {
					/* send a report immediately */
					mld6_sendpkt(in6m, MLD_LISTENER_REPORT,
						NULL);
					in6m->in6m_timer = 0; /* reset timer */
					in6m->in6m_state = MLD6_IREPORTEDLAST;
				}
				else if (in6m->in6m_timer == 0 || /* idle */
					in6m->in6m_timer > timer) {
					in6m->in6m_timer =
						MLD6_RANDOM_DELAY(timer);
					mld6_timers_are_running = 1;
				}
			}
		}

		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
			mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
		break;
	case MLD_LISTENER_REPORT:
		/*
		 * For fast leave to work, we have to know that we are the
		 * last person to send a report for this group.  Reports
		 * can potentially get looped back if we are a multicast
		 * router, so discard reports sourced by me.
		 * Note that it is impossible to check IFF_LOOPBACK flag of
		 * ifp for this purpose, since ip6_mloopback pass the physical
		 * interface to looutput.
		 */
		if (m->m_flags & M_LOOP) /* XXX: grotty flag, but efficient */
			break;

		if (!IN6_IS_ADDR_MULTICAST(&mldh->mld_addr))
			break;

		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
			mldh->mld_addr.s6_addr16[1] =
				htons(ifp->if_index); /* XXX */
		/*
		 * If we belong to the group being reported, stop
		 * our timer for that group.
		 */
		IN6_LOOKUP_MULTI(mldh->mld_addr, ifp, in6m);
		if (in6m) {
			in6m->in6m_timer = 0; /* transit to idle state */
			in6m->in6m_state = MLD6_OTHERLISTENER; /* clear flag */
		}

		if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
			mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
		break;
	default:		/* this is impossible */
		log(LOG_ERR, "mld6_input: illegal type(%d)", mldh->mld_type);
		break;
	}

	m_freem(m);
}

void
mld6_fasttimeo()
{
	struct in6_multi *in6m;
	struct in6_multistep step;
	int s;

	/*
	 * Quick check to see if any work needs to be done, in order
	 * to minimize the overhead of fasttimo processing.
	 */
	if (!mld6_timers_are_running)
		return;

#ifdef __NetBSD__
	s = splsoftnet();
#else
	s = splnet();
#endif
	mld6_timers_are_running = 0;
	IN6_FIRST_MULTI(step, in6m);
	while (in6m != NULL) {
		if (in6m->in6m_timer == 0) {
			/* do nothing */
		} else if (--in6m->in6m_timer == 0) {
			mld6_sendpkt(in6m, MLD_LISTENER_REPORT, NULL);
			in6m->in6m_state = MLD6_IREPORTEDLAST;
		} else {
			mld6_timers_are_running = 1;
		}
		IN6_NEXT_MULTI(step, in6m);
	}
	splx(s);
}

static void
mld6_sendpkt(in6m, type, dst)
	struct in6_multi *in6m;
	int type;
	const struct in6_addr *dst;
{
	struct mbuf *mh, *md;
	struct mld_hdr *mldh;
	struct ip6_hdr *ip6;
	struct ip6_moptions im6o;
	struct in6_ifaddr *ia;
	struct ifnet *ifp = in6m->in6m_ifp;
	int ignflags;

	/*
	 * At first, find a link local address on the outgoing interface
	 * to use as the source address of the MLD packet.
	 * We do not reject tentative addresses for MLD report to deal with
	 * the case where we first join a link-local address.
	 */
	ignflags = (IN6_IFF_NOTREADY|IN6_IFF_ANYCAST) & ~IN6_IFF_TENTATIVE;
	if ((ia = in6ifa_ifpforlinklocal(ifp, ignflags)) == NULL)
		return;
	if ((ia->ia6_flags & IN6_IFF_TENTATIVE))
		ia = NULL;

	/*
	 * Allocate mbufs to store ip6 header and MLD header.
	 * We allocate 2 mbufs and make chain in advance because
	 * it is more convenient when inserting the hop-by-hop option later.
	 */
	MGETHDR(mh, M_DONTWAIT, MT_HEADER);
	if (mh == NULL)
		return;
	MGET(md, M_DONTWAIT, MT_DATA);
	if (md == NULL) {
		m_free(mh);
		return;
	}
	mh->m_next = md;

	mh->m_pkthdr.rcvif = NULL;
	mh->m_pkthdr.len = sizeof(struct ip6_hdr) + sizeof(struct mld_hdr);
	mh->m_len = sizeof(struct ip6_hdr);
	MH_ALIGN(mh, sizeof(struct ip6_hdr));

	/* fill in the ip6 header */
	ip6 = mtod(mh, struct ip6_hdr *);
	ip6->ip6_flow = 0;
	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
	ip6->ip6_vfc |= IPV6_VERSION;
	/* ip6_plen will be set later */
	ip6->ip6_nxt = IPPROTO_ICMPV6;
	/* ip6_hlim will be set by im6o.im6o_multicast_hlim */
	ip6->ip6_src = ia ? ia->ia_addr.sin6_addr : in6addr_any;
	ip6->ip6_dst = dst ? *dst : in6m->in6m_addr;

	/* fill in the MLD header */
	md->m_len = sizeof(struct mld_hdr);
	mldh = mtod(md, struct mld_hdr *);
	mldh->mld_type = type;
	mldh->mld_code = 0;
	mldh->mld_cksum = 0;
	/* XXX: we assume the function will not be called for query messages */
	mldh->mld_maxdelay = 0;
	mldh->mld_reserved = 0;
	mldh->mld_addr = in6m->in6m_addr;
	if (IN6_IS_ADDR_MC_LINKLOCAL(&mldh->mld_addr))
		mldh->mld_addr.s6_addr16[1] = 0; /* XXX */
	mldh->mld_cksum = in6_cksum(mh, IPPROTO_ICMPV6,
				     sizeof(struct ip6_hdr),
				     sizeof(struct mld_hdr));

	/* construct multicast option */
	bzero(&im6o, sizeof(im6o));
	im6o.im6o_multicast_ifp = ifp;
	im6o.im6o_multicast_hlim = 1;

	/*
	 * Request loopback of the report if we are acting as a multicast
	 * router, so that the process-level routing daemon can hear it.
	 */
	im6o.im6o_multicast_loop = (ip6_mrouter != NULL);

	/* increment output statictics */
	icmp6stat.icp6s_outhist[type]++;
	icmp6_ifstat_inc(ifp, ifs6_out_msg);
	switch (type) {
	case MLD_LISTENER_QUERY:
		icmp6_ifstat_inc(ifp, ifs6_out_mldquery);
		break;
	case MLD_LISTENER_REPORT:
		icmp6_ifstat_inc(ifp, ifs6_out_mldreport);
		break;
	case MLD_LISTENER_DONE:
		icmp6_ifstat_inc(ifp, ifs6_out_mlddone);
		break;
	}

	ip6_output(mh, &ip6_opts, NULL, ia ? 0 : IPV6_UNSPECSRC, &im6o, NULL);
}