ip6_input.c

来自「eCos操作系统源码」· C语言 代码 · 共 2,515 行 · 第 1/5 页

	if (m && m->m_next != NULL && m->m_pkthdr.len < MCLBYTES) {
		struct mbuf *n;

		MGETHDR(n, M_DONTWAIT, MT_HEADER);
		if (n != NULL) {
#ifdef __OpenBSD__
			M_MOVE_PKTHDR(n, m);
#else
			M_COPY_PKTHDR(n, m);
#endif
		}
		if (n != NULL && m->m_pkthdr.len > MHLEN) {
			MCLGET(n, M_DONTWAIT);
			if ((n->m_flags & M_EXT) == 0) {
				m_freem(n);
				n = NULL;
			}
		}
		if (n == NULL) {
			m_freem(m);
			return;	/* ENOBUFS */
		}

		m_copydata(m, 0, m->m_pkthdr.len, mtod(n, caddr_t));
		n->m_len = m->m_pkthdr.len;
		m_freem(m);
		m = n;
	}
	IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), /* nothing */);
#endif

#if defined(__OpenBSD__) && NPF > 0 
	/*
	 * Packet filter
	 */
	if (pf_test6(PF_IN, m->m_pkthdr.rcvif, &m) != PF_PASS)
		goto bad;
#endif

	if (m->m_len < sizeof(struct ip6_hdr)) {
		struct ifnet *inifp;
		inifp = m->m_pkthdr.rcvif;
		if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == 0) {
			ip6stat.ip6s_toosmall++;
			in6_ifstat_inc(inifp, ifs6_in_hdrerr);
			return;
		}
	}

	ip6 = mtod(m, struct ip6_hdr *);

	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
		ip6stat.ip6s_badvers++;
		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
		goto bad;
	}

#if defined(__NetBSD__) && defined(PFIL_HOOKS)
	/*
	 * Run through list of hooks for input packets.  If there are any
	 * filters which require that additional packets in the flow are
	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
	 * Note that filters must _never_ set this flag, as another filter
	 * in the list may have previously cleared it.
	 */
	/*
	 * let ipfilter look at packet on the wire,
	 * not the decapsulated packet.
	 */
#ifdef IPSEC
	if (!ipsec_getnhist(m))
#else
	if (1 /* CONSTCOND */)
#endif
	{
		m0 = m;
		pfh = pfil_hook_get(PFIL_IN,
		    &inetsw[ip_protox[IPPROTO_IPV6]].pr_pfh);
	} else
		pfh = NULL;
	for (; pfh; pfh = pfh->pfil_link.tqe_next)
		if (pfh->pfil_func) {
			rv = pfh->pfil_func(ip6, sizeof(*ip6),
					    m->m_pkthdr.rcvif, 0, &m0);
			if (rv)
				return;
			m = m0;
			if (m == NULL)
				return;
			ip6 = mtod(m, struct ip6_hdr *);
		}
#endif /* PFIL_HOOKS */

	ip6stat.ip6s_nxthist[ip6->ip6_nxt]++;

#if defined(IPV6FIREWALL) || (defined(__FreeBSD__) && __FreeBSD__ >= 4)
	/*
	 * Check with the firewall...
	 */
#if defined(__FreeBSD__) && __FreeBSD__ >= 4
	if (ip6_fw_enable && ip6_fw_chk_ptr)
#else
	if (ip6_fw_chk_ptr)
#endif
	{
		/* If ipfw says divert, we have to just drop packet */
		/* use port as a dummy argument */
		if ((*ip6_fw_chk_ptr)(&ip6, NULL, &m)) {
			m_freem(m);
			m = NULL;
		}
		if (!m)
			return;
	}
#endif

#ifdef ALTQ
	if (altq_input != NULL && (*altq_input)(m, AF_INET6) == 0) {
		/* packet is dropped by traffic conditioner */
		return;
	}
#endif

	/*
	 * Check against address spoofing/corruption.
	 */
#if 0
            diag_printf("%s.%d\n", __FUNCTION__, __LINE__);
            diag_dump_buf(&ip6->ip6_src, 16);
            diag_dump_buf(&ip6->ip6_dst, 16);
#endif
	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
	    IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
		/*
		 * XXX: "badscope" is not very suitable for a multicast source.
		 */
		ip6stat.ip6s_badscope++;
		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
                log(LOG_FAIL, "%s.%d\n", __FUNCTION__, __LINE__);
		goto bad;
	}
	if ((IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
	     IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) &&
	    (m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
		ip6stat.ip6s_badscope++;
		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
                log(LOG_FAIL, "%s.%d\n", __FUNCTION__, __LINE__);
		goto bad;
	}
	if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
	    !(m->m_flags & M_LOOP)) {
		/*
		 * In this case, the packet should come from the loopback
		 * interface.  However, we cannot just check the if_flags,
		 * because ip6_mloopback() passes the "actual" interface
		 * as the outgoing/incoming interface.
		 */
		ip6stat.ip6s_badscope++;
		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
                log(LOG_FAIL, "%s.%d\n", __FUNCTION__, __LINE__);
		goto bad;
	}
	     
	/*
	 * The following check is not documented in specs.  A malicious
	 * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
	 * and bypass security checks (act as if it was from 127.0.0.1 by using
	 * IPv6 src ::ffff:127.0.0.1).  Be cautious.
	 *
	 * This check chokes if we are in an SIIT cloud.  As none of BSDs
	 * support IPv4-less kernel compilation, we cannot support SIIT
	 * environment at all.  So, it makes more sense for us to reject any
	 * malicious packets for non-SIIT environment, than try to do a
	 * partical support for SIIT environment.
	 */
	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
		ip6stat.ip6s_badscope++;
		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
                log(LOG_FAIL, "%s.%d\n", __FUNCTION__, __LINE__);
		goto bad;
	}
#if 0
	/*
	 * Reject packets with IPv4 compatible addresses (auto tunnel).
	 *
	 * The code forbids auto tunnel relay case in RFC1933 (the check is
	 * stronger than RFC1933).  We may want to re-enable it if mech-xx
	 * is revised to forbid relaying case.
	 */
	if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
	    IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
		ip6stat.ip6s_badscope++;
		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
		goto bad;
	}
#endif

	/* drop packets if interface ID portion is already filled */
	if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src) &&
		    ip6->ip6_src.s6_addr16[1]) {
			ip6stat.ip6s_badscope++;
                        log(LOG_FAIL, "%s.%d\n", __FUNCTION__, __LINE__);
			goto bad;
		}
		if ((IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) ||
		     IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) &&
		    ip6->ip6_dst.s6_addr16[1]) {
			ip6stat.ip6s_badscope++;
                        log(LOG_FAIL, "%s.%d\n", __FUNCTION__, __LINE__);
			goto bad;
		}
	}

	/*
	 * Embed interface ID as the zone ID for interface-local and
	 * link-local addresses.
	 * XXX: KAME assumes one-to-one mapping between interfaces and
	 * links.
	 */
	if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
		ip6->ip6_src.s6_addr16[1]
			= htons(m->m_pkthdr.rcvif->if_index);
	if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) ||
	    IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
		ip6->ip6_dst.s6_addr16[1]
			= htons(m->m_pkthdr.rcvif->if_index);

#if 0 /* this case seems to be unnecessary. (jinmei, 20010401) */
	/*
	 * We use rt->rt_ifp to determine if the address is ours or not.
	 * If rt_ifp is lo0, the address is ours.
	 * The problem here is, rt->rt_ifp for fe80::%lo0/64 is set to lo0,
	 * so any address under fe80::%lo0/64 will be mistakenly considered
	 * local.  The special case is supplied to handle the case properly
	 * by actually looking at interface addresses
	 * (using in6ifa_ifpwithaddr).
	 */
	if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) != 0 &&
	    IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst)) {
		if (!in6ifa_ifpwithaddr(m->m_pkthdr.rcvif, &ip6->ip6_dst)) {
			icmp6_error(m, ICMP6_DST_UNREACH,
			    ICMP6_DST_UNREACH_ADDR, 0);
			/* m is already freed */
			return;
		}

		ours = 1;
		deliverifp = m->m_pkthdr.rcvif;
		goto hbhcheck;
	}
#endif

	/*
	 * Multicast check
	 */
	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
	  	struct	in6_multi *in6m = 0;

		in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mcast);
		/*
		 * See if we belong to the destination multicast group on the
		 * arrival interface.
		 */
		IN6_LOOKUP_MULTI(ip6->ip6_dst, m->m_pkthdr.rcvif, in6m);
// TEMP
                if (0) {
                    struct in6_addr *_addr = &ip6->ip6_dst;
                    struct ifnet *_ifp = m->m_pkthdr.rcvif;
                    struct ifmultiaddr *_ifma; 
                    diag_printf("Lookup Multi = %p\n", in6m);
                    diag_dump_buf(_addr, 16);
                    diag_printf("=====================================================================\n");
                    for (_ifma = (_ifp)->if_multiaddrs.lh_first; _ifma; 
                         _ifma = _ifma->ifma_link.le_next) { 
                        diag_dump_buf(&((struct sockaddr_in6 *)_ifma->ifma_addr)->sin6_addr, 16);
                        diag_printf("---------------------------------------------------------------------\n");
                    } 
                }
// TEMP
		if (in6m)
			ours = 1;
		else if (!ip6_mrouter) {
			ip6stat.ip6s_notmember++;
			ip6stat.ip6s_cantforward++;
			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
                        log(LOG_FAIL, "%s.%d - wrong multi group\n", 
                            __FUNCTION__, __LINE__);
                        log_dump(LOG_FAIL, &ip6->ip6_dst, 16);
			goto bad;
		}
		deliverifp = m->m_pkthdr.rcvif;
		goto hbhcheck;
	}

	/*
	 *  Unicast check
	 */
#ifdef MEASURE_PERFORMANCE
	ctr_beg = read_tsc();
#endif
	switch (ip6_ours_check_algorithm) {
#ifdef MEASURE_PERFORMANCE
	case OURS_CHECK_ALG_LINEAR:
	/* traditional linear search: just for measurement */
	{
		struct in6_ifaddr *ia;

		for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
			if ((ia->ia6_flags & IN6_IFF_NOTREADY) == 0 &&
			    IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
					       &ip6->ip6_dst)) {
#ifdef MEASURE_PERFORMANCE
				ctr_end = read_tsc();
#ifdef MEASURE_PERFORMANCE_UDPONLY
				if (ip6->ip6_nxt == IPPROTO_UDP)
#else
				if (1)
#endif
					add_performance_log(ctr_end - ctr_beg,
							    &ip6->ip6_dst);
#endif
				/* record address information into m_aux. */
				(void)ip6_setdstifaddr(m, ia);

				ours = 1;
				deliverifp = ia->ia_ifp;
				goto hbhcheck;
			}
		}
	}
	break;
	case OURS_CHECK_ALG_HASH:
	case OURS_CHECK_ALG_LARGEHASH:
	{
		struct in6_ifaddr *ia;
		struct in6hash *ih = NULL;

		if ((ih = in6h_lookup(&ip6->ip6_dst, m->m_pkthdr.rcvif)) !=
		    NULL && (ia = ih->in6h_ifa) != NULL) {
#ifdef MEASURE_PERFORMANCE
			ctr_end = read_tsc();
#ifdef MEASURE_PERFORMANCE_UDPONLY
			if (ip6->ip6_nxt == IPPROTO_UDP)
#else
			if (1)
#endif
				add_performance_log(ctr_end - ctr_beg,
						    &ip6->ip6_dst);
#endif

			/* record address information into m_aux. */
			(void)ip6_setdstifaddr(m, ia);

			ours = 1;
			deliverifp = m->m_pkthdr.rcvif;
			goto hbhcheck;
		}
	}
	break;
#endif /* MEASURE_PERFORMANCE */
	default:
		/*
		 * XXX: I intentionally broke our indentation rule here,
		 *      since this switch-case is just for measurement and
		 *      therefore should soon be removed.
		 */
	if (ip6_forward_rt.ro_rt != NULL &&
	    (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) != 0 && 
	    IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
			       &((struct sockaddr_in6 *)(&ip6_forward_rt.ro_dst))->sin6_addr))
		ip6stat.ip6s_forward_cachehit++;
	else {
		struct sockaddr_in6 *dst6;
#ifdef SCOPEDROUTING
		int64_t dstzone;
#endif

		if (ip6_forward_rt.ro_rt) {
			/* route is down or destination is different */
			ip6stat.ip6s_forward_cachemiss++;
			RTFREE(ip6_forward_rt.ro_rt);
			ip6_forward_rt.ro_rt = 0;
		}

		bzero(&ip6_forward_rt.ro_dst, sizeof(struct sockaddr_in6));
		dst6 = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
		dst6->sin6_len = sizeof(struct sockaddr_in6);
		dst6->sin6_family = AF_INET6;
		dst6->sin6_addr = ip6->ip6_dst;
#ifdef SCOPEDROUTING
		if ((dstzone = in6_addr2zoneid(m->m_pkthdr.rcvif,
					       &ip6->ip6_dst)) < 0) {
			ip6stat.ip6s_badscope++;
			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
                        log(LOG_FAIL, "%s.%d\n", __FUNCTION__, __LINE__);
			goto bad;
		}
		ip6_forward_rt.ro_dst.sin6_scope_id = dstzone;
#endif

#ifdef __FreeBSD__
		rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING);
#else
		rtalloc((struct route *)&ip6_forward_rt);
#endif
	}

#define rt6_key(r) ((struct sockaddr_in6 *)((r)->rt_nodes->rn_key))

	/*
	 * Accept the packet if the forwarding interface to the destination
	 * according to the routing table is the loopback interface,
	 * unless the associated route has a gateway.
	 * Note that this approach causes to accept a packet if there is a
	 * route to the loopback interface for the destination of the packet.
	 * But we think it's even useful in some situations, e.g. when using
	 * a special daemon which wants to intercept the packet.
	 *
	 * XXX: some OSes automatically make a cloned route for the destination
	 * of an outgoing packet.  If the outgoing interface of the packet
	 * is a loopback one, the kernel would consider the packet to be
	 * accepted, even if we have no such address assinged on the interface.
	 * We check the cloned flag of the route entry to reject such cases,
	 * assuming that route entries for our own addresses are not made by
	 * cloning (it should be true because in6_addloop explicitly installs
	 * the host route).  However, we might have to do an explicit check
	 * while it would be less efficient.  Or, should we rather install a
	 * reject route for such a case?
	 */
	if (ip6_forward_rt.ro_rt &&
	    (ip6_forward_rt.ro_rt->rt_flags &
	     (RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
#ifdef RTF_WASCLONED
	    !(ip6_forward_rt.ro_rt->rt_flags & RTF_WASCLONED) &&
#endif
#ifdef RTF_CLONED
	    !(ip6_forward_rt.ro_rt->rt_flags & RTF_CLONED) &&
#endif
#if 0
	    /*
	     * The check below is redundant since the comparison of
	     * the destination and the key of the rtentry has
	     * already done through looking up the routing table.
	     */
	    IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
				&rt6_key(ip6_forward_rt.ro_rt)->sin6_addr)
#endif
	    ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_LOOP) {
		struct in6_ifaddr *ia6 =
			(struct in6_ifaddr *)ip6_forward_rt.ro_rt->rt_ifa;

#ifdef MEASURE_PERFORMANCE
		ctr_end = read_tsc();
#ifdef MEASURE_PERFORMANCE_UDPONLY
		if (ip6->ip6_nxt == IPPROTO_UDP)
#else
		if (1)
#endif
			add_performance_log(ctr_end - ctr_beg, &ip6->ip6_dst);
#endif

		/*
		 * record address information into m_aux.
		 */
		(void)ip6_setdstifaddr(m, ia6);

		/*
		 * packets to a tentative, duplicated, or somehow invalid
		 * address must not be accepted.
		 */
		if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
			/* this address is ready */
			ours = 1;
			deliverifp = ia6->ia_ifp;	/* correct? */
#if defined(__FreeBSD__) && __FreeBSD__ >= 4
			/* Count the packet in the ip address stats */
			ia6->ia_ifa.if_ipackets++;
			ia6->ia_ifa.if_ibytes += m->m_pkthdr.len;
#elif defined(__bsdi__) && _BSDI_VERSION >= 199802
			/* Count the packet in the ip address stats */
			ia6->ia_ifa.ifa_ipackets++;
			ia6->ia_ifa.ifa_ibytes += m->m_pkthdr.len;
#endif
			goto hbhcheck;
		} else {
			/* address is not ready, so discard the packet. */
			nd6log((LOG_INFO,
			    "ip6_input: packet to an unready address %s->%s\n",
			    ip6_sprintf(&ip6->ip6_src),
			    ip6_sprintf(&ip6->ip6_dst)));
			goto bad;
		}
	}
	} /* XXX indentation (see above) */

#ifdef MEASURE_PERFORMANCE
	/* we detected that packet is not ours thru the basic algorithm */
	ctr_end = read_tsc();
#ifdef MEASURE_PERFORMANCE_UDPONLY
	if (ip6->ip6_nxt == IPPROTO_UDP)
#else