Ejemplo n.º 1
0
/*
 * Input a Neighbor Solicitation Message.
 *
 * Based on RFC 2461
 * Based on RFC 2462 (duplicate address detection)
 */
void
nd6_ns_input(struct mbuf *m, int off, int icmp6len)
{
	struct ifnet *ifp = m->m_pkthdr.rcvif;
	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
	struct nd_neighbor_solicit *nd_ns;
	struct in6_addr saddr6 = ip6->ip6_src;
	struct in6_addr daddr6 = ip6->ip6_dst;
	struct in6_addr taddr6;
	struct in6_addr myaddr6;
	char *lladdr = NULL;
	struct ifaddr *ifa = NULL;
	int lladdrlen = 0;
	int anycast = 0, proxy = 0, tentative = 0;
	int tlladdr;
	int rflag;
	union nd_opts ndopts;
	struct sockaddr_dl proxydl;
	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];

	rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
	if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
		rflag = 0;
#ifndef PULLDOWN_TEST
	IP6_EXTHDR_CHECK(m, off, icmp6len,);
	nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
#else
	IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
	if (nd_ns == NULL) {
		ICMP6STAT_INC(icp6s_tooshort);
		return;
	}
#endif
	ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
	taddr6 = nd_ns->nd_ns_target;
	if (in6_setscope(&taddr6, ifp, NULL) != 0)
		goto bad;

	if (ip6->ip6_hlim != 255) {
		nd6log((LOG_ERR,
		    "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
		    ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
		    ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
		goto bad;
	}

	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
		/* dst has to be a solicited node multicast address. */
		if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
		    /* don't check ifindex portion */
		    daddr6.s6_addr32[1] == 0 &&
		    daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
		    daddr6.s6_addr8[12] == 0xff) {
			; /* good */
		} else {
			nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
			    "(wrong ip6 dst)\n"));
			goto bad;
		}
	} else if (!V_nd6_onlink_ns_rfc4861) {
		struct sockaddr_in6 src_sa6;

		/*
		 * According to recent IETF discussions, it is not a good idea
		 * to accept a NS from an address which would not be deemed
		 * to be a neighbor otherwise.  This point is expected to be
		 * clarified in future revisions of the specification.
		 */
		bzero(&src_sa6, sizeof(src_sa6));
		src_sa6.sin6_family = AF_INET6;
		src_sa6.sin6_len = sizeof(src_sa6);
		src_sa6.sin6_addr = saddr6;
		if (nd6_is_addr_neighbor(&src_sa6, ifp) == 0) {
			nd6log((LOG_INFO, "nd6_ns_input: "
				"NS packet from non-neighbor\n"));
			goto bad;
		}
	}

	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
		nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
		goto bad;
	}

	icmp6len -= sizeof(*nd_ns);
	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
	if (nd6_options(&ndopts) < 0) {
		nd6log((LOG_INFO,
		    "nd6_ns_input: invalid ND option, ignored\n"));
		/* nd6_options have incremented stats */
		goto freeit;
	}

	if (ndopts.nd_opts_src_lladdr) {
		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
	}

	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
		nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
		    "(link-layer address option)\n"));
		goto bad;
	}

	/*
	 * Attaching target link-layer address to the NA?
	 * (RFC 2461 7.2.4)
	 *
	 * NS IP dst is unicast/anycast			MUST NOT add
	 * NS IP dst is solicited-node multicast	MUST add
	 *
	 * In implementation, we add target link-layer address by default.
	 * We do not add one in MUST NOT cases.
	 */
	if (!IN6_IS_ADDR_MULTICAST(&daddr6))
		tlladdr = 0;
	else
		tlladdr = 1;

	/*
	 * Target address (taddr6) must be either:
	 * (1) Valid unicast/anycast address for my receiving interface,
	 * (2) Unicast address for which I'm offering proxy service, or
	 * (3) "tentative" address on which DAD is being performed.
	 */
	/* (1) and (3) check. */
	if (ifp->if_carp)
		ifa = (*carp_iamatch6_p)(ifp, &taddr6);
	else
		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);

	/* (2) check. */
	if (ifa == NULL) {
		struct route_in6 ro;
		int need_proxy;

		bzero(&ro, sizeof(ro));
		ro.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
		ro.ro_dst.sin6_family = AF_INET6;
		ro.ro_dst.sin6_addr = taddr6;

		/* Always use the default FIB. */
#ifdef RADIX_MPATH
		rtalloc_mpath_fib((struct route *)&ro, RTF_ANNOUNCE,
		    RT_DEFAULT_FIB);
#else
		in6_rtalloc(&ro, RT_DEFAULT_FIB);
#endif
		need_proxy = (ro.ro_rt &&
		    (ro.ro_rt->rt_flags & RTF_ANNOUNCE) != 0 &&
		    ro.ro_rt->rt_gateway->sa_family == AF_LINK);
		if (ro.ro_rt != NULL) {
			if (need_proxy)
				proxydl = *SDL(ro.ro_rt->rt_gateway);
			RTFREE(ro.ro_rt);
		}
		if (need_proxy) {
			/*
			 * proxy NDP for single entry
			 */
			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
				IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
			if (ifa)
				proxy = 1;
		}
	}
	if (ifa == NULL) {
		/*
		 * We've got an NS packet, and we don't have that adddress
		 * assigned for us.  We MUST silently ignore it.
		 * See RFC2461 7.2.3.
		 */
		goto freeit;
	}
	myaddr6 = *IFA_IN6(ifa);
	anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
	tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
	if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
		goto freeit;

	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
		nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
		    "(if %d, NS packet %d)\n",
		    ip6_sprintf(ip6bufs, &taddr6),
		    ifp->if_addrlen, lladdrlen - 2));
		goto bad;
	}

	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
		nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
		    ip6_sprintf(ip6bufs, &saddr6)));
		goto freeit;
	}

	/*
	 * We have neighbor solicitation packet, with target address equals to
	 * one of my tentative address.
	 *
	 * src addr	how to process?
	 * ---		---
	 * multicast	of course, invalid (rejected in ip6_input)
	 * unicast	somebody is doing address resolution -> ignore
	 * unspec	dup address detection
	 *
	 * The processing is defined in RFC 2462.
	 */
	if (tentative) {
		/*
		 * If source address is unspecified address, it is for
		 * duplicate address detection.
		 *
		 * If not, the packet is for addess resolution;
		 * silently ignore it.
		 */
		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
			nd6_dad_ns_input(ifa, ndopts.nd_opts_nonce);

		goto freeit;
	}

	/*
	 * If the source address is unspecified address, entries must not
	 * be created or updated.
	 * It looks that sender is performing DAD.  Output NA toward
	 * all-node multicast address, to tell the sender that I'm using
	 * the address.
	 * S bit ("solicited") must be zero.
	 */
	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
		struct in6_addr in6_all;

		in6_all = in6addr_linklocal_allnodes;
		if (in6_setscope(&in6_all, ifp, NULL) != 0)
			goto bad;
		nd6_na_output_fib(ifp, &in6_all, &taddr6,
		    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
		    rflag, tlladdr, proxy ? (struct sockaddr *)&proxydl : NULL,
		    M_GETFIB(m));
		goto freeit;
	}

	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
	    ND_NEIGHBOR_SOLICIT, 0);

	nd6_na_output_fib(ifp, &saddr6, &taddr6,
	    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
	    rflag | ND_NA_FLAG_SOLICITED, tlladdr,
	    proxy ? (struct sockaddr *)&proxydl : NULL, M_GETFIB(m));
 freeit:
	if (ifa != NULL)
		ifa_free(ifa);
	m_freem(m);
	return;

 bad:
	nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
		ip6_sprintf(ip6bufs, &saddr6)));
	nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
		ip6_sprintf(ip6bufs, &daddr6)));
	nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
		ip6_sprintf(ip6bufs, &taddr6)));
	ICMP6STAT_INC(icp6s_badns);
	if (ifa != NULL)
		ifa_free(ifa);
	m_freem(m);
}
Ejemplo n.º 2
0
/*
 * Input an Neighbor Solicitation Message.
 *
 * Based on RFC 2461
 * Based on RFC 2462 (duplicated address detection)
 */
void
nd6_ns_input(struct mbuf *m, int off, int icmp6len)
{
	struct ifnet *ifp = m->m_pkthdr.rcvif;
	struct ifnet *cmpifp;
	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
	struct nd_neighbor_solicit *nd_ns;
	struct in6_addr saddr6 = ip6->ip6_src;
	struct in6_addr daddr6 = ip6->ip6_dst;
	struct in6_addr taddr6;
	struct in6_addr myaddr6;
	char *lladdr = NULL;
	struct ifaddr *ifa = NULL;
	int lladdrlen = 0;
	int anycast = 0, proxy = 0, tentative = 0;
	int tlladdr;
	union nd_opts ndopts;
	struct sockaddr_dl *proxydl = NULL;

	/*
	 * Collapse interfaces to the bridge for comparison and
	 * mac (llinfo) purposes.
	 */
	cmpifp = ifp;
	if (ifp->if_bridge)
		cmpifp = ifp->if_bridge;

#ifndef PULLDOWN_TEST
	IP6_EXTHDR_CHECK(m, off, icmp6len,);
	nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
#else
	IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
	if (nd_ns == NULL) {
		icmp6stat.icp6s_tooshort++;
		return;
	}
#endif
	ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
	taddr6 = nd_ns->nd_ns_target;

	if (ip6->ip6_hlim != 255) {
		nd6log((LOG_ERR,
		    "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
		    ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
		    ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
		goto bad;
	}

	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
		/* dst has to be solicited node multicast address. */
		if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
		    /* don't check ifindex portion */
		    daddr6.s6_addr32[1] == 0 &&
		    daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
		    daddr6.s6_addr8[12] == 0xff) {
			; /* good */
		} else {
			nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
			    "(wrong ip6 dst)\n"));
			goto bad;
		}
	} else if (!nd6_onlink_ns_rfc4861) {
		/*
		 * Make sure the source address is from a neighbor's address.
		 *
		 * XXX probably only need to check cmpifp.
		 */
		if (in6ifa_ifplocaladdr(cmpifp, &saddr6) == NULL &&
		    in6ifa_ifplocaladdr(ifp, &saddr6) == NULL) {
			nd6log((LOG_INFO, "nd6_ns_input: "
			    "NS packet from non-neighbor\n"));
			goto bad;
		}
	}

	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
		nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
		goto bad;
	}

	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
		taddr6.s6_addr16[1] = htons(ifp->if_index);

	icmp6len -= sizeof(*nd_ns);
	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
	if (nd6_options(&ndopts) < 0) {
		nd6log((LOG_INFO,
		    "nd6_ns_input: invalid ND option, ignored\n"));
		/* nd6_options have incremented stats */
		goto freeit;
	}

	if (ndopts.nd_opts_src_lladdr) {
		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
	}

	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
		nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
		    "(link-layer address option)\n"));
		goto bad;
	}

	/*
	 * Attaching target link-layer address to the NA?
	 * (RFC 2461 7.2.4)
	 *
	 * NS IP dst is unicast/anycast			MUST NOT add
	 * NS IP dst is solicited-node multicast	MUST add
	 *
	 * In implementation, we add target link-layer address by default.
	 * We do not add one in MUST NOT cases.
	 */
#if 0 /* too much! */
	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
	if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
		tlladdr = 0;
	else
#endif
	if (!IN6_IS_ADDR_MULTICAST(&daddr6))
		tlladdr = 0;
	else
		tlladdr = 1;

	/*
	 * Target address (taddr6) must be either:
	 * (1) Valid unicast/anycast address for my receiving interface.
	 * (2) Unicast or anycast address for which I'm offering proxy
	 *     service.
	 * (3) "tentative" address on which DAD is being performed.
	 */
	/* (1) and (3) check. */
#ifdef CARP
	if (ifp->if_carp)
		ifa = carp_iamatch6(ifp->if_carp, &taddr6);
	if (!ifa)
		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#else
	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#endif

	/*
	 * (2) Check proxying.  Requires ip6_forwarding to be turned on.
	 *
	 *     If the packet is anycast the target route must be on a
	 *     different interface because the anycast will get anything
	 *     on the current interface.
	 *
	 *     If the packet is unicast the target route may be on the
	 *     same interface.  If the gateway is a (typically manually
	 *     configured) link address we can directly offer it.
	 *     XXX for now we don't do this but instead offer ours and
	 *     presumably relay.
	 *
	 *     WARNING! Since this is a subnet proxy the interface proxying
	 *     the ND6 must be in promiscuous mode or it will not see the
	 *     solicited multicast requests for various hosts being proxied.
	 *
	 *     WARNING! Since this is a subnet proxy we have to treat bridge
	 *     interfaces as being the bridge itself so we do not proxy-nd6
	 *     between bridge interfaces (which are effectively switched).
	 *
	 *     (In the specific-host-proxy case via RTF_ANNOUNCE, which is
	 *     a bitch to configure, a specific multicast route is already
	 *     added for that host <-- NOT RECOMMENDED).
	 */
	if (!ifa && ip6_forwarding) {
		struct rtentry *rt;
		struct sockaddr_in6 tsin6;
		struct ifnet *rtifp;

		bzero(&tsin6, sizeof tsin6);
		tsin6.sin6_len = sizeof(struct sockaddr_in6);
		tsin6.sin6_family = AF_INET6;
		tsin6.sin6_addr = taddr6;

		rt = rtpurelookup((struct sockaddr *)&tsin6);
		rtifp = rt ? rt->rt_ifp : NULL;
		if (rtifp && rtifp->if_bridge)
			rtifp = rtifp->if_bridge;

		if (rt != NULL &&
		    (cmpifp != rtifp ||
		     (cmpifp == rtifp && (m->m_flags & M_MCAST) == 0))
		) {
			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(cmpifp,
				IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
			nd6log((LOG_INFO,
			       "nd6_ns_input: nd6 proxy %s(%s)<-%s ifa %p\n",
			       if_name(cmpifp), if_name(ifp),
			       if_name(rtifp), ifa));
			if (ifa) {
				proxy = 1;
				/*
				 * Manual link address on same interface
				 * w/announce flag will proxy-arp using
				 * target mac, else our mac is used.
				 */
				if (cmpifp == rtifp &&
				    (rt->rt_flags & RTF_ANNOUNCE) &&
				    rt->rt_gateway->sa_family == AF_LINK) {
					proxydl = SDL(rt->rt_gateway);
				}
			}
		}
		if (rt != NULL)
			--rt->rt_refcnt;
	}
	if (ifa == NULL) {
		/*
		 * We've got an NS packet, and we don't have that adddress
		 * assigned for us.  We MUST silently ignore it.
		 * See RFC2461 7.2.3.
		 */
		goto freeit;
	}
	myaddr6 = *IFA_IN6(ifa);
	anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
	tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
	if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
		goto freeit;

	if (lladdr && ((cmpifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
		nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
		    "(if %d, NS packet %d)\n",
		    ip6_sprintf(&taddr6), cmpifp->if_addrlen, lladdrlen - 2));
		goto bad;
	}

	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
		nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
		    ip6_sprintf(&saddr6)));
		goto freeit;
	}

	/*
	 * We have neighbor solicitation packet, with target address equals to
	 * one of my tentative address.
	 *
	 * src addr	how to process?
	 * ---		---
	 * multicast	of course, invalid (rejected in ip6_input)
	 * unicast	somebody is doing address resolution -> ignore
	 * unspec	dup address detection
	 *
	 * The processing is defined in RFC 2462.
	 */
	if (tentative) {
		/*
		 * If source address is unspecified address, it is for
		 * duplicated address detection.
		 *
		 * If not, the packet is for addess resolution;
		 * silently ignore it.
		 */
		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
			nd6_dad_ns_input(ifa);

		goto freeit;
	}

	/*
	 * If the source address is unspecified address, entries must not
	 * be created or updated.
	 * It looks that sender is performing DAD.  Output NA toward
	 * all-node multicast address, to tell the sender that I'm using
	 * the address.
	 * S bit ("solicited") must be zero.
	 */
	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
		saddr6 = kin6addr_linklocal_allnodes;
		saddr6.s6_addr16[1] = htons(cmpifp->if_index);
		nd6_na_output(cmpifp, &saddr6, &taddr6,
		    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
		    (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
		    tlladdr, (struct sockaddr *)proxydl);
		goto freeit;
	}

	nd6_cache_lladdr(cmpifp, &saddr6, lladdr, lladdrlen,
	    ND_NEIGHBOR_SOLICIT, 0);

	nd6_na_output(ifp, &saddr6, &taddr6,
	    ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
	    (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
	    tlladdr, (struct sockaddr *)proxydl);
freeit:
	m_freem(m);
	return;

bad:
	nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
	nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
	nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
	icmp6stat.icp6s_badns++;
	m_freem(m);
}
Ejemplo n.º 3
0
/*
 * Input a Neighbor Solicitation Message.
 *
 * Based on RFC 2461
 * Based on RFC 2462 (duplicate address detection)
 */
void
nd6_ns_input(struct mbuf *m, int off, int icmp6len)
{
    struct ifnet *ifp = m->m_pkthdr.rcvif;
    struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
    struct nd_neighbor_solicit *nd_ns;
    struct in6_addr saddr6 = ip6->ip6_src;
    struct in6_addr daddr6 = ip6->ip6_dst;
    struct in6_addr taddr6;
    struct in6_addr myaddr6;
    char *lladdr = NULL;
    struct ifaddr *ifa;
    int lladdrlen = 0;
    int anycast = 0, proxy = 0, tentative = 0;
    int router = ip6_forwarding;
    int tlladdr;
    union nd_opts ndopts;
    const struct sockaddr_dl *proxydl = NULL;

    IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
    if (nd_ns == NULL) {
        ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
        return;
    }
    ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
    taddr6 = nd_ns->nd_ns_target;
    if (in6_setscope(&taddr6, ifp, NULL) != 0)
        goto bad;

    if (ip6->ip6_hlim != 255) {
        nd6log((LOG_ERR,
                "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
                ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
                ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
        goto bad;
    }

    if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
        /* dst has to be a solicited node multicast address. */
        /* don't check ifindex portion */
        if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
                daddr6.s6_addr32[1] == 0 &&
                daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
                daddr6.s6_addr8[12] == 0xff) {
            ; /* good */
        } else {
            nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
                    "(wrong ip6 dst)\n"));
            goto bad;
        }
    } else {
        struct sockaddr_in6 ssin6;

        /*
         * Make sure the source address is from a neighbor's address.
         */
        sockaddr_in6_init(&ssin6, &saddr6, 0, 0, 0);
        if (nd6_is_addr_neighbor(&ssin6, ifp) == 0) {
            nd6log((LOG_INFO, "nd6_ns_input: "
                    "NS packet from non-neighbor\n"));
            goto bad;
        }
    }


    if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
        nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
        goto bad;
    }

    icmp6len -= sizeof(*nd_ns);
    nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
    if (nd6_options(&ndopts) < 0) {
        nd6log((LOG_INFO,
                "nd6_ns_input: invalid ND option, ignored\n"));
        /* nd6_options have incremented stats */
        goto freeit;
    }

    if (ndopts.nd_opts_src_lladdr) {
        lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
        lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
    }

    if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
        nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
                "(link-layer address option)\n"));
        goto bad;
    }

    /*
     * Attaching target link-layer address to the NA?
     * (RFC 2461 7.2.4)
     *
     * NS IP dst is multicast			MUST add
     * Otherwise					MAY be omitted
     *
     * In this implementation, we omit the target link-layer address
     * in the "MAY" case.
     */
#if 0 /* too much! */
    ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
    if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
        tlladdr = 0;
    else
#endif
        if (!IN6_IS_ADDR_MULTICAST(&daddr6))
            tlladdr = 0;
        else
            tlladdr = 1;

    /*
     * Target address (taddr6) must be either:
     * (1) Valid unicast/anycast address for my receiving interface,
     * (2) Unicast address for which I'm offering proxy service, or
     * (3) "tentative" address on which DAD is being performed.
     */
    /* (1) and (3) check. */
#if NCARP > 0
    if (ifp->if_carp && ifp->if_type != IFT_CARP)
        ifa = carp_iamatch6(ifp->if_carp, &taddr6);
    else
        ifa = NULL;
    if (!ifa)
        ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#else
    ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#endif

    /* (2) check. */
    if (ifa == NULL) {
        struct rtentry *rt;
        struct sockaddr_in6 tsin6;

        sockaddr_in6_init(&tsin6, &taddr6, 0, 0, 0);

        rt = rtalloc1((struct sockaddr *)&tsin6, 0);
        if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
                rt->rt_gateway->sa_family == AF_LINK) {
            /*
             * proxy NDP for single entry
             */
            ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
                    IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
            if (ifa) {
                proxy = 1;
                proxydl = satocsdl(rt->rt_gateway);
                router = 0;	/* XXX */
            }
        }
        if (rt)
            rtfree(rt);
    }
    if (ifa == NULL) {
        /*
         * We've got an NS packet, and we don't have that address
         * assigned for us.  We MUST silently ignore it.
         * See RFC2461 7.2.3.
         */
        goto freeit;
    }
    myaddr6 = *IFA_IN6(ifa);
    anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
    tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
    if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
        goto freeit;

    if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
        nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
                "(if %d, NS packet %d)\n",
                ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2));
        goto bad;
    }

    if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
        nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
                ip6_sprintf(&saddr6)));
        goto freeit;
    }

    /*
     * We have neighbor solicitation packet, with target address equals to
     * one of my tentative address.
     *
     * src addr	how to process?
     * ---		---
     * multicast	of course, invalid (rejected in ip6_input)
     * unicast	somebody is doing address resolution -> ignore
     * unspec	dup address detection
     *
     * The processing is defined in RFC 2462.
     */
    if (tentative) {
        /*
         * If source address is unspecified address, it is for
         * duplicate address detection.
         *
         * If not, the packet is for addess resolution;
         * silently ignore it.
         */
        if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
            nd6_dad_ns_input(ifa);

        goto freeit;
    }

    /*
     * If the source address is unspecified address, entries must not
     * be created or updated.
     * It looks that sender is performing DAD.  Output NA toward
     * all-node multicast address, to tell the sender that I'm using
     * the address.
     * S bit ("solicited") must be zero.
     */
    if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
        struct in6_addr in6_all;

        in6_all = in6addr_linklocal_allnodes;
        if (in6_setscope(&in6_all, ifp, NULL) != 0)
            goto bad;
        nd6_na_output(ifp, &in6_all, &taddr6,
                      ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
                      (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
                      tlladdr, (const struct sockaddr *)proxydl);
        goto freeit;
    }

    nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);

    nd6_na_output(ifp, &saddr6, &taddr6,
                  ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
                  (router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
                  tlladdr, (const struct sockaddr *)proxydl);
freeit:
    m_freem(m);
    return;

bad:
    nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
    nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
    nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
    ICMP6_STATINC(ICMP6_STAT_BADNS);
    m_freem(m);
}
Ejemplo n.º 4
0
void
nd6_ns_input (T_NET_BUF *input, uint_t off)
{
	T_IFNET			*ifp = IF_GET_IFNET();
	T_IP6_HDR		*ip6h;
	T_NEIGHBOR_SOLICIT_HDR	*nsh;
	T_ND_OPT_HDR		*opth;
	T_IN6_IFADDR		*ifa;
	bool_t			tlladdr;
	uint_t			lladdr_len = 0;
	uint32_t		flags;
	uint8_t			*lladdr = NULL;
	uint8_t			nd_opt_off[ND_OPT_OFF_ARRAY_SIZE];

	NET_COUNT_ICMP6(net_count_nd6[NC_ND6_NS_IN_PACKETS], 1);

	ip6h = GET_IP6_HDR(input);

	/*
	 *  ヘッダのチェック、以下の場合は破棄する。
	 *    ・ホップリミットが IPV6_MAXHLIM (255) 以外
	 *    ・ヘッダ長が短い
	 */
	if (ip6h->hlim != IPV6_MAXHLIM || input->len - off < NEIGHBOR_SOLICIT_HDR_SIZE)
		goto err_ret;

	nsh  = (T_NEIGHBOR_SOLICIT_HDR *)(input->buf + off);

	if (IN6_IS_ADDR_UNSPECIFIED(&ip6h->src)) {
		/*
		 *  始点アドレスが無指定なら、重複アドレス検出
		 *  あて先アドレスは、要請マルチキャストでなければならない。
		 */
		if (!IN6_IS_ADDR_NS_MULTICAST(&ip6h->dst))
			goto err_ret;
		}

	/* 目的アドレスがマルチキャストならエラー */
	if (IN6_IS_ADDR_MULTICAST(&nsh->target))
		goto err_ret;

	/* 近隣探索オプションのオフセットを記録する。*/
	if (nd6_options(nd_opt_off, input->buf + (off + NEIGHBOR_SOLICIT_HDR_SIZE),
	                            input->len - (off + NEIGHBOR_SOLICIT_HDR_SIZE)) != E_OK)
		goto err_ret;

	/* 近隣探索オプション (始点リンクアドレス) */
	if (nd_opt_off[ND_OPT_OFF_ARRAY_IX(ND_OPT_SOURCE_LINKADDR)]) {
		opth = (T_ND_OPT_HDR *)((uint8_t *)(input->buf + off + NEIGHBOR_SOLICIT_HDR_SIZE) +
		                        nd_opt_off[ND_OPT_OFF_ARRAY_IX(ND_OPT_SOURCE_LINKADDR)] - 8);
	 	/* 注意: オプションオフセット配列には、オフセット + 8 が設定されている。*/
		lladdr     = (uint8_t *)(opth + 1);
		lladdr_len = (opth->len << 3);
		}

	if (IN6_IS_ADDR_UNSPECIFIED(&ip6h->src) && lladdr != NULL)
		goto err_ret;

	/* 宛先アドレスがマルチキャストなら近隣通知にデータリンク層のアドレスを付ける。*/
	if (IN6_IS_ADDR_MULTICAST(&ip6h->dst))
		tlladdr = true;
	else
		tlladdr = false;

	/*
	 *  目的アドレスが、自分のネットワークインタフェースに
	 *  割り当てられているアドレスか調べる。
	 *  なお、代理サービスは実装していない。
	 */
	ifa = in6_lookup_ifaddr(ifp, &nsh->target);

	if (ifa == NULL)
		goto free_ret;

	/* 探索結果アドレスが重複していれば応答しないで終了する。*/
	if (ifa->flags & IN6_IFF_DUPLICATED)
		goto err_ret;

	/*
	 *  ネットワークインタフェースのアドレス長が一致しなければエラー
	 */
	if (lladdr && lladdr_len != ((sizeof(T_IF_ADDR) + sizeof(T_ND_OPT_HDR) + 7) & ~7))
		goto err_ret;

	/*
	 *  始点アドレスが自分のアドレスと一致すれば重複している。
	 */
	if (IN6_ARE_ADDR_EQUAL(&ifa->addr, &ip6h->src))
		goto free_ret;

	/* 重複検出中に、近隣要請を受信したときの処理 */
	if (ifa->flags & IN6_IFF_TENTATIVE) {
		if (IN6_IS_ADDR_UNSPECIFIED(&ip6h->src))
			nd6_dad_ns_input(ifp, ifa);
		goto free_ret;
		}

	if ((ifa->flags & IN6_IFF_ANYCAST) || !tlladdr)
		flags = 0;
	else
		flags = ND_NA_FLG_OVERRIDE;

	/*
	 *  始点アドレスが無指定なら、送信相手は重複アドレス検出中で、
	 *  直接送信することはできないので、全ノードマルチキャスト
	 *  アドレスに送信する。
	 */
	if (IN6_IS_ADDR_UNSPECIFIED(&ip6h->src)) {
		nd6_na_output(ifp, &in6_addr_linklocal_allnodes, &nsh->target, flags, tlladdr);
		goto free_ret;
		}

	/* 近隣キャッシュに登録する。*/
	nd6_cache_lladdr(ifp, &ip6h->src, (T_IF_ADDR *)lladdr, ND_NEIGHBOR_SOLICIT, 0);

	nd6_na_output(ifp, &ip6h->src, &nsh->target, flags | ND_NA_FLG_SOLICITED, tlladdr);

free_ret:
	syscall(rel_net_buf(input));
	return;

err_ret:
	NET_COUNT_ICMP6(net_count_nd6[NC_ICMP6_IN_ERR_PACKETS], 1);
	syscall(rel_net_buf(input));
	}