nd6_nbr.c

来自「eCos操作系统源码」· C语言 代码 · 共 1,526 行 · 第 1/3 页

//==========================================================================
//
//      src/sys/netinet6/nd6_nbr.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*	$KAME: nd6_nbr.c,v 1.83 2001/12/18 02:06:55 itojun Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/queue.h>
#ifdef __OpenBSD__
#include <dev/rndvar.h>
#endif

#include <net/if.h>
#include <net/if_types.h>
#include <net/if_dl.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet/icmp6.h>

#ifdef __OpenBSD__	/* don't confuse KAME ipsec with OpenBSD ipsec */
#undef IPSEC
#endif

#ifdef IPSEC
#include <netinet6/ipsec.h>
#endif

#ifdef MIP6
#include <netinet6/mip6.h>
#endif /* MIP6 */

#define SDL(s) ((struct sockaddr_dl *)s)

struct dadq;
static struct dadq *nd6_dad_find __P((struct ifaddr *));
static void nd6_dad_starttimer __P((struct dadq *, int));
static void nd6_dad_stoptimer __P((struct dadq *));
static void nd6_dad_timer __P((struct ifaddr *));
static void nd6_dad_ns_output __P((struct dadq *, struct ifaddr *));
static void nd6_dad_ns_input __P((struct ifaddr *));
static void nd6_dad_na_input __P((struct ifaddr *));

static int dad_ignore_ns = 0;	/* ignore NS in DAD - specwise incorrect*/
static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */

/*
 * Input an Neighbor Solicitation Message.
 *
 * Based on RFC 2461
 * Based on RFC 2462 (duplicated address detection)
 */
void
nd6_ns_input(m, off, icmp6len)
	struct mbuf *m;
	int off, 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 tlladdr;
	union nd_opts ndopts;
	struct sockaddr_dl *proxydl = NULL;

#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;
		}
	}

	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 address for which I'm offering proxy service, or
	 * (3) "tentative" address on which DAD is being performed.
	 */
	/* (1) and (3) check. */
	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);

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

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

		rt = rtalloc1((struct sockaddr *)&tsin6, 0
#ifdef __FreeBSD__
			      , 0
#endif /* __FreeBSD__ */
			      );
		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 = SDL(rt->rt_gateway);
			}
		}
		if (rt)
			rtfree(rt);
	}
#ifdef MIP6
	if (!ifa) {
		ifa = mip6_dad_find(&taddr6, ifp);
	}
#endif
	if (!ifa) {
		/*
		 * 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(&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
		 * 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 = in6addr_linklocal_allnodes;
		saddr6.s6_addr16[1] = htons(ifp->if_index);
		nd6_na_output(ifp, &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(ifp, &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);
}

/*
 * Output an Neighbor Solicitation Message. Caller specifies:
 *	- ICMP6 header source IP6 address
 *	- ND6 header target IP6 address
 *	- ND6 header source datalink address
 *
 * Based on RFC 2461
 * Based on RFC 2462 (duplicated address detection)
 */
void
nd6_ns_output(ifp, daddr6, taddr6, ln, dad)
	struct ifnet *ifp;
	const struct in6_addr *daddr6, *taddr6;
	struct llinfo_nd6 *ln;	/* for source address determination */
	int dad;	/* duplicated address detection */
{
	struct mbuf *m;
	struct ip6_hdr *ip6;
	struct nd_neighbor_solicit *nd_ns;
	struct in6_ifaddr *ia = NULL;
	struct ip6_moptions im6o;
	int icmp6len;
	int maxlen;
	caddr_t mac;
	struct sockaddr_in6 sin6_in;
#ifdef MIP6
	int unicast_ns = 0;
#endif
	
	if (IN6_IS_ADDR_MULTICAST(taddr6))
		return;

	/* estimate the size of message */
	maxlen = sizeof(*ip6) + sizeof(*nd_ns);
	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
#ifdef DIAGNOSTIC
	if (max_linkhdr + maxlen >= MCLBYTES) {
		printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
		panic("nd6_ns_output: insufficient MCLBYTES");
		/* NOTREACHED */
	}
#endif

	MGETHDR(m, M_DONTWAIT, MT_DATA);
	if (m && max_linkhdr + maxlen >= MHLEN) {
		MCLGET(m, M_DONTWAIT);
		if ((m->m_flags & M_EXT) == 0) {
			m_free(m);
			m = NULL;
		}
	}
	if (m == NULL)
		return;
	m->m_pkthdr.rcvif = NULL;

#ifdef MIP6
	if (MIP6_IS_MN && daddr6 == NULL && !dad) {
		struct hif_softc *sc;
		struct mip6_bu *mbu;

		/* 10.20. Returning Home */
		for (sc = TAILQ_FIRST(&hif_softc_list);
		     sc;
		     sc = TAILQ_NEXT(sc, hif_entry)) {
			mbu = mip6_bu_list_find_withpaddr(
							&sc->hif_bu_list,
							(struct in6_addr *)taddr6);
			if (mbu == NULL)
				continue;
			if ((mbu->mbu_flags & IP6_BUF_HOME) == 0)
				continue;
			if (mbu->mbu_reg_state ==
					MIP6_BU_REG_STATE_DEREGWAITACK) {
				/* unspecified source */
				dad = 1;
				if (ln && ND6_IS_LLINFO_PROBREACH(ln))
					unicast_ns = 1;
			}
			break;
		}
	}
	if (!unicast_ns)
#endif
	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
		m->m_flags |= M_MCAST;
		im6o.im6o_multicast_ifp = ifp;
		im6o.im6o_multicast_hlim = 255;
		im6o.im6o_multicast_loop = 0;
	}

	icmp6len = sizeof(*nd_ns);
	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
	m->m_data += max_linkhdr;	/* or MH_ALIGN() equivalent? */

	/* fill neighbor solicitation packet */
	ip6 = mtod(m, struct ip6_hdr *);
	ip6->ip6_flow = 0;
	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
	ip6->ip6_vfc |= IPV6_VERSION;
	/* ip6->ip6_plen will be set later */
	ip6->ip6_nxt = IPPROTO_ICMPV6;
	ip6->ip6_hlim = 255;
	if (daddr6)
		ip6->ip6_dst = *daddr6;
#ifdef MIP6
	else if (unicast_ns)
		ip6->ip6_dst = *taddr6;
#endif
	else {
		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
		ip6->ip6_dst.s6_addr32[1] = 0;
		ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
		ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
		ip6->ip6_dst.s6_addr8[12] = 0xff;
	}
	if (!dad) {
		/*
		 * RFC2461 7.2.2:
		 * "If the source address of the packet prompting the
		 * solicitation is the same as one of the addresses assigned
		 * to the outgoing interface, that address SHOULD be placed
		 * in the IP Source Address of the outgoing solicitation.
		 * Otherwise, any one of the addresses assigned to the
		 * interface should be used."
		 *
		 * We use the source address for the prompting packet
		 * (saddr6), if:
		 * - saddr6 is given from the caller (by giving "ln"), and
		 * - saddr6 belongs to the outgoing interface.
		 * Otherwise, we perform a scope-wise match.
		 */
		struct ip6_hdr *hip6;		/* hold ip6 */
		struct in6_addr *saddr6;

		if (ln && ln->ln_hold) {
			hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
			if (sizeof(*hip6) < ln->ln_hold->m_len) {
				int zone;

				bzero(&sin6_in, sizeof(sin6_in));
				sin6_in.sin6_family = AF_INET6;
				sin6_in.sin6_len = sizeof(sin6_in);
				sin6_in.sin6_addr = hip6->ip6_src;
				zone = in6_addr2zoneid(ifp,
						       &sin6_in.sin6_addr);
				if (zone < 0) /* XXX: should not happen! */
					goto bad;
				sin6_in.sin6_scope_id = zone;
				in6_embedscope(&sin6_in.sin6_addr, &sin6_in);
				saddr6 = &sin6_in.sin6_addr;
			} else
				saddr6 = NULL;
		} else
			saddr6 = NULL;
		if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
			bcopy(saddr6, &ip6->ip6_src, sizeof(*saddr6));