icmp6.c

eCos操作系统源码

//==========================================================================
//
//      src/sys/netinet6/icmp6.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: icmp6.c,v 1.269 2001/12/18 02:19:16 jinmei 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.
 */

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *	@(#)ip_icmp.c	8.2 (Berkeley) 1/4/94
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/domain.h>

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

#include <netinet/in.h>
#include <netinet/in_var.h>
#if defined(__OpenBSD__) || (defined(__bsdi__) && _BSDI_VERSION >= 199802)
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#endif
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet6/mld6_var.h>
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
#include <netinet/in_pcb.h>
#include <netinet6/in6_pcb.h>
#elif defined(__OpenBSD__) || (defined(__bsdi__) && _BSDI_VERSION >= 199802)
#include <netinet/in_pcb.h>
#else
#include <netinet6/in6_pcb.h>
#endif
#include <netinet6/nd6.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/ip6protosw.h>

#ifdef __OpenBSD__ /* KAME IPSEC */
#undef IPSEC
#endif

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

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

#ifdef HAVE_NRL_INPCB
/* inpcb members */
#define in6pcb		inpcb
#define in6p_laddr	inp_laddr6
#define in6p_faddr	inp_faddr6
#define in6p_icmp6filt	inp_icmp6filt
#define in6p_route	inp_route
#define in6p_socket	inp_socket
#define in6p_flags	inp_flags
#define in6p_moptions	inp_moptions6
#define in6p_outputopts	inp_outputopts6
#define in6p_ip6	inp_ipv6
#define in6p_flowinfo	inp_flowinfo
#define in6p_sp		inp_sp
#define in6p_next	inp_next
#define in6p_prev	inp_prev

/*
 * for KAME src sync over BSD*'s.  XXX: FreeBSD (>=3) are VERY different from
 * others...
 */
#define in6p_ip6_nxt	inp_ipv6.ip6_nxt
#endif

extern struct domain inet6domain;
extern struct ip6protosw inet6sw[];
extern u_char ip6_protox[];

struct icmp6stat icmp6stat;

#if defined (__OpenBSD__)
extern struct inpcbtable rawin6pcbtable;
#elif !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
extern struct in6pcb rawin6pcb;
#else
extern struct inpcbhead ripcb;
#endif
extern int icmp6errppslim;
static int icmp6errpps_count = 0;
static struct timeval icmp6errppslim_last;
extern int icmp6_nodeinfo;
#if defined(__NetBSD__) || defined(__OpenBSD__)
/*
 * List of callbacks to notify when Path MTU changes are made.
 */
struct icmp6_mtudisc_callback {
	LIST_ENTRY(icmp6_mtudisc_callback) mc_list;
	void (*mc_func) __P((struct in6_addr *));
};

LIST_HEAD(, icmp6_mtudisc_callback) icmp6_mtudisc_callbacks =
    LIST_HEAD_INITIALIZER(&icmp6_mtudisc_callbacks);

static struct rttimer_queue *icmp6_mtudisc_timeout_q = NULL;
extern int pmtu_expire;

/* XXX do these values make any sense? */
static int icmp6_mtudisc_hiwat = 1280;
static int icmp6_mtudisc_lowat = 256;

/*
 * keep track of # of redirect routes.
 */
static struct rttimer_queue *icmp6_redirect_timeout_q = NULL;

/* XXX do these values make any sense? */
static int icmp6_redirect_hiwat = 1280;
static int icmp6_redirect_lowat = 1024;
#endif

static void icmp6_errcount __P((struct icmp6errstat *, int, int));
static int icmp6_rip6_input __P((struct mbuf **, int));
static int icmp6_ratelimit __P((const struct in6_addr *, const int, const int));
static const char *icmp6_redirect_diag __P((struct in6_addr *,
	struct in6_addr *, struct in6_addr *));
#ifndef HAVE_PPSRATECHECK
static int ppsratecheck __P((struct timeval *, int *, int));
#endif
static struct mbuf *ni6_input __P((struct mbuf *, int));
static struct mbuf *ni6_nametodns __P((const char *, int, int));
static int ni6_dnsmatch __P((const char *, int, const char *, int));
static int ni6_addrs __P((struct icmp6_nodeinfo *, struct mbuf *,
			  struct ifnet **, char *));
static int ni6_store_addrs __P((struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
				struct ifnet *, int));
static int icmp6_notify_error __P((struct mbuf *, int, int, int));
static int icmp6_recover_src __P((struct mbuf *));
#if defined(__NetBSD__) || defined(__OpenBSD__)
static struct rtentry *icmp6_mtudisc_clone __P((struct sockaddr *));
static void icmp6_mtudisc_timeout __P((struct rtentry *, struct rttimer *));
static void icmp6_redirect_timeout __P((struct rtentry *, struct rttimer *));
#endif

void
icmp6_init()
{
	mld6_init();
#if defined(__NetBSD__) || defined(__OpenBSD__)
	icmp6_mtudisc_timeout_q = rt_timer_queue_create(pmtu_expire);
	icmp6_redirect_timeout_q = rt_timer_queue_create(icmp6_redirtimeout);
#endif
}

static void
icmp6_errcount(stat, type, code)
	struct icmp6errstat *stat;
	int type, code;
{
	switch (type) {
	case ICMP6_DST_UNREACH:
		switch (code) {
		case ICMP6_DST_UNREACH_NOROUTE:
			stat->icp6errs_dst_unreach_noroute++;
			return;
		case ICMP6_DST_UNREACH_ADMIN:
			stat->icp6errs_dst_unreach_admin++;
			return;
		case ICMP6_DST_UNREACH_BEYONDSCOPE:
			stat->icp6errs_dst_unreach_beyondscope++;
			return;
		case ICMP6_DST_UNREACH_ADDR:
			stat->icp6errs_dst_unreach_addr++;
			return;
		case ICMP6_DST_UNREACH_NOPORT:
			stat->icp6errs_dst_unreach_noport++;
			return;
		}
		break;
	case ICMP6_PACKET_TOO_BIG:
		stat->icp6errs_packet_too_big++;
		return;
	case ICMP6_TIME_EXCEEDED:
		switch (code) {
		case ICMP6_TIME_EXCEED_TRANSIT:
			stat->icp6errs_time_exceed_transit++;
			return;
		case ICMP6_TIME_EXCEED_REASSEMBLY:
			stat->icp6errs_time_exceed_reassembly++;
			return;
		}
		break;
	case ICMP6_PARAM_PROB:
		switch (code) {
		case ICMP6_PARAMPROB_HEADER:
			stat->icp6errs_paramprob_header++;
			return;
		case ICMP6_PARAMPROB_NEXTHEADER:
			stat->icp6errs_paramprob_nextheader++;
			return;
		case ICMP6_PARAMPROB_OPTION:
			stat->icp6errs_paramprob_option++;
			return;
		}
		break;
	case ND_REDIRECT:
		stat->icp6errs_redirect++;
		return;
	}
	stat->icp6errs_unknown++;
}

#if defined(__NetBSD__) || defined(__OpenBSD__)
/*
 * Register a Path MTU Discovery callback.
 */
void
icmp6_mtudisc_callback_register(func)
	void (*func) __P((struct in6_addr *));
{
	struct icmp6_mtudisc_callback *mc;

	for (mc = LIST_FIRST(&icmp6_mtudisc_callbacks); mc != NULL;
	     mc = LIST_NEXT(mc, mc_list)) {
		if (mc->mc_func == func)
			return;
	}

	mc = malloc(sizeof(*mc), M_PCB, M_NOWAIT);
	if (mc == NULL)
		panic("icmp6_mtudisc_callback_register");

	mc->mc_func = func;
	LIST_INSERT_HEAD(&icmp6_mtudisc_callbacks, mc, mc_list);
}
#endif

/*
 * Generate an error packet of type error in response to bad IP6 packet.
 */
void
icmp6_error(m, type, code, param)
	struct mbuf *m;
	int type, code, param;
{
	struct ip6_hdr *oip6, *nip6;
	struct icmp6_hdr *icmp6;
	struct mbuf *n;
	struct ip6aux *ip6a;
	struct in6_addr nip6_src, *nip6_srcp;
	u_int preplen;
	int off;
	int nxt;

	icmp6stat.icp6s_error++;

	/* count per-type-code statistics */
	icmp6_errcount(&icmp6stat.icp6s_outerrhist, type, code);

#ifdef M_DECRYPTED	/* not openbsd */
	if (m->m_flags & M_DECRYPTED) {
		icmp6stat.icp6s_canterror++;
		goto freeit;
	}
#endif

#ifndef PULLDOWN_TEST
	IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
#else
	if (m->m_len < sizeof(struct ip6_hdr)) {
		m = m_pullup(m, sizeof(struct ip6_hdr));
		if (m == NULL)
			return;
	}
#endif
	oip6 = mtod(m, struct ip6_hdr *);

	/*
	 * If the destination address of the erroneous packet is a multicast
	 * address, or the packet was sent using link-layer multicast,
	 * we should basically suppress sending an error (RFC 2463, Section
	 * 2.4).
	 * We have two exceptions (the item e.2 in that section):
	 * - the Pakcet Too Big message can be sent for path MTU discovery.
	 * - the Parameter Problem Message that can be allowed an icmp6 error
	 *   in the option type field.  This check has been done in
	 *   ip6_unknown_opt(), so we can just check the type and code.
	 */
	if ((m->m_flags & (M_BCAST|M_MCAST) ||
	     IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
	    (type != ICMP6_PACKET_TOO_BIG &&
	     (type != ICMP6_PARAM_PROB ||
	      code != ICMP6_PARAMPROB_OPTION)))
		goto freeit;

	/*
	 * RFC 2463, 2.4 (e.5): source address check.
	 * XXX: the case of anycast source?
	 */
	if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
	    IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
		goto freeit;

	/*
	 * If we are about to send ICMPv6 against ICMPv6 error/redirect,
	 * don't do it.
	 */
	nxt = -1;
	off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
	if (off >= 0 && nxt == IPPROTO_ICMPV6) {
		struct icmp6_hdr *icp;

#ifndef PULLDOWN_TEST
		IP6_EXTHDR_CHECK(m, 0, off + sizeof(struct icmp6_hdr), );
		icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
#else
		IP6_EXTHDR_GET(icp, struct icmp6_hdr *, m, off,
			sizeof(*icp));
		if (icp == NULL) {
			icmp6stat.icp6s_tooshort++;
			return;
		}
#endif
		if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
		    icp->icmp6_type == ND_REDIRECT) {
			/*
			 * ICMPv6 error
			 * Special case: for redirect (which is
			 * informational) we must not send icmp6 error.
			 */
			icmp6stat.icp6s_canterror++;
			goto freeit;
		} else {
			/* ICMPv6 informational - send the error */
		}
	}
#if 0 /* controversial */
	else if (off >= 0 && nxt == IPPROTO_ESP) {
		/*
		 * It could be ICMPv6 error inside ESP.  Take a safer side,
		 * don't respond.
		 */
		icmp6stat.icp6s_canterror++;
		goto freeit;
	}
#endif
	else {
		/* non-ICMPv6 - send the error */
	}

	oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */

	/* Finally, do rate limitation check. */
	if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
		icmp6stat.icp6s_toofreq++;
		goto freeit;
	}

	/*
	 * OK, ICMP6 can be generated.
	 */

	/*
	 * Recover the original ip6_src if the src and the homeaddr
	 * have been swapped while dest6 processing (see dest6.c).  To
	 * avoid m_pulldown, we had better to swap addresses before
	 * m_prepend below.
	 *
	 * XXX: We should consider the other candidate to keep the
	 * icmp6 error packet correct that not swapping ip6_src and
	 * homeaddr in the dest6 processing.
	 */
	nip6_srcp = &oip6->ip6_src;
	n = ip6_findaux(m);
	if (n != NULL) {
		ip6a = mtod(n, struct ip6aux *);
		if ((ip6a->ip6a_flags & IP6A_HASEEN) != 0 &&
		    (ip6a->ip6a_flags & IP6A_SWAP) != 0) {
			nip6_src = oip6->ip6_src;
			nip6_srcp = &nip6_src;
			if (icmp6_recover_src(m)) {
				/* mbuf is freed in icmp6_recover_src */
				return;
			}
			oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */
		}
	}

	if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
		m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);

	preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
	M_PREPEND(m, preplen, M_DONTWAIT);
	if (m && m->m_len < preplen)
		m = m_pullup(m, preplen);
	if (m == NULL) {
		nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
		return;
	}

	nip6 = mtod(m, struct ip6_hdr *);
	nip6->ip6_src  = *nip6_srcp;
	nip6->ip6_dst  = oip6->ip6_dst;

	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
		oip6->ip6_src.s6_addr16[1] = 0;
	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
		oip6->ip6_dst.s6_addr16[1] = 0;

	icmp6 = (struct icmp6_hdr *)(nip6 + 1);