nd6_rtr.c

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//==========================================================================
//
//      src/sys/netinet6/nd6_rtr.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_rtr.c,v 1.187 2001/12/18 02:01:25 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/time.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 <net/radix.h>

#include <netinet/in.h>
#include <netinet6/in6_var.h>
#include <netinet6/in6_ifattach.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet/icmp6.h>
#include <netinet6/scope6_var.h>

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

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

static int rtpref __P((struct nd_defrouter *));
static struct nd_defrouter *defrtrlist_update __P((struct nd_defrouter *));
static struct in6_ifaddr *in6_ifadd __P((struct nd_prefix *));
static struct nd_pfxrouter *pfxrtr_lookup __P((struct nd_prefix *,
	struct nd_defrouter *));
static void pfxrtr_add __P((struct nd_prefix *, struct nd_defrouter *));
static void pfxrtr_del __P((struct nd_pfxrouter *));
static struct nd_pfxrouter *find_pfxlist_reachable_router
	__P((struct nd_prefix *));
static void defrouter_delreq __P((struct nd_defrouter *));
static void defrouter_addifreq __P((struct ifnet *));
static void defrouter_delifreq __P((void));
static void nd6_rtmsg __P((int, struct rtentry *));

static void in6_init_address_ltimes __P((struct nd_prefix *ndpr,
					 struct in6_addrlifetime *lt6));

static int rt6_deleteroute __P((struct radix_node *, void *));

extern int nd6_recalc_reachtm_interval;

static struct ifnet *nd6_defifp;
int nd6_defifindex;
static struct ifaddr *nd6_defif_installed = NULL;

int ip6_use_tempaddr = 0;

int ip6_desync_factor;
u_int32_t ip6_temp_preferred_lifetime = DEF_TEMP_PREFERRED_LIFETIME;
u_int32_t ip6_temp_valid_lifetime = DEF_TEMP_VALID_LIFETIME;
int ip6_temp_regen_advance = TEMPADDR_REGEN_ADVANCE;

/* RTPREF_MEDIUM has to be 0! */
#define RTPREF_HIGH	1
#define RTPREF_MEDIUM	0
#define RTPREF_LOW	(-1)
#define RTPREF_INVALID	(-2)

/*
 * Receive Router Solicitation Message - just for routers.
 * Router solicitation/advertisement is mostly managed by userland program
 * (rtadvd) so here we have no function like nd6_ra_output().
 *
 * Based on RFC 2461
 */
void
nd6_rs_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_router_solicit *nd_rs;
	struct in6_addr saddr6 = ip6->ip6_src;
#if 0
	struct in6_addr daddr6 = ip6->ip6_dst;
#endif
	char *lladdr = NULL;
	int lladdrlen = 0;
#if 0
	struct sockaddr_dl *sdl = (struct sockaddr_dl *)NULL;
	struct llinfo_nd6 *ln = (struct llinfo_nd6 *)NULL;
	struct rtentry *rt = NULL;
	int is_newentry;
#endif
	union nd_opts ndopts;

	/* If I'm not a router, ignore it. */
	if (ip6_accept_rtadv != 0 || ip6_forwarding != 1)
		goto freeit;

	/* Sanity checks */
	if (ip6->ip6_hlim != 255) {
		nd6log((LOG_ERR,
		    "nd6_rs_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;
	}

	/*
	 * Don't update the neighbor cache, if src = ::.
	 * This indicates that the src has no IP address assigned yet.
	 */
	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
		goto freeit;

#ifndef PULLDOWN_TEST
	IP6_EXTHDR_CHECK(m, off, icmp6len,);
	nd_rs = (struct nd_router_solicit *)((caddr_t)ip6 + off);
#else
	IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
	if (nd_rs == NULL) {
		icmp6stat.icp6s_tooshort++;
		return;
	}
#endif

	icmp6len -= sizeof(*nd_rs);
	nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
	if (nd6_options(&ndopts) < 0) {
		nd6log((LOG_INFO,
		    "nd6_rs_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 (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
		nd6log((LOG_INFO,
		    "nd6_rs_input: lladdrlen mismatch for %s "
		    "(if %d, RS packet %d)\n",
			ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2));
		goto bad;
	}

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

 freeit:
	m_freem(m);
	return;

 bad:
	icmp6stat.icp6s_badrs++;
	m_freem(m);
}

/*
 * Receive Router Advertisement Message.
 *
 * Based on RFC 2461
 * TODO: on-link bit on prefix information
 * TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
 */
void
nd6_ra_input(m, off, icmp6len)
	struct	mbuf *m;
	int off, icmp6len;
{
	struct ifnet *ifp = m->m_pkthdr.rcvif;
	struct nd_ifinfo *ndi = &nd_ifinfo[ifp->if_index];
	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
	struct nd_router_advert *nd_ra;
	struct in6_addr saddr6 = ip6->ip6_src;
#if 0
	struct in6_addr daddr6 = ip6->ip6_dst;
	int flags; /* = nd_ra->nd_ra_flags_reserved; */
	int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
	int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
#endif
	union nd_opts ndopts;
	struct nd_defrouter *dr;

	/*
	 * We only accept RAs only when
	 * the system-wide variable allows the acceptance, and
	 * per-interface variable allows RAs on the receiving interface.  
	 */
	if (ip6_accept_rtadv == 0)
		goto freeit;
	if (!(nd_ifinfo[ifp->if_index].flags & ND6_IFF_ACCEPT_RTADV))
		goto freeit;

	if (ip6->ip6_hlim != 255) {
		nd6log((LOG_ERR,
		    "nd6_ra_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_LINKLOCAL(&saddr6)) {
		nd6log((LOG_ERR,
		    "nd6_ra_input: src %s is not link-local\n",
		    ip6_sprintf(&saddr6)));
		goto bad;
	}

#ifndef PULLDOWN_TEST
	IP6_EXTHDR_CHECK(m, off, icmp6len,);
	nd_ra = (struct nd_router_advert *)((caddr_t)ip6 + off);
#else
	IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
	if (nd_ra == NULL) {
		icmp6stat.icp6s_tooshort++;
		return;
	}
#endif

	icmp6len -= sizeof(*nd_ra);
	nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
	if (nd6_options(&ndopts) < 0) {
		nd6log((LOG_INFO,
		    "nd6_ra_input: invalid ND option, ignored\n"));
		/* nd6_options have incremented stats */
		goto freeit;
	}

    {
	struct nd_defrouter dr0;
	u_int32_t advreachable = nd_ra->nd_ra_reachable;
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
	long time_second = time.tv_sec;
#endif

	Bzero(&dr0, sizeof(dr0));
	dr0.rtaddr = saddr6;
	dr0.flags  = nd_ra->nd_ra_flags_reserved;
	dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
	dr0.expire = time_second + dr0.rtlifetime;
	dr0.ifp = ifp;
	dr0.advint = 0;		/* Mobile IPv6 */
	dr0.advint_expire = 0;	/* Mobile IPv6 */
	dr0.advints_lost = 0;	/* Mobile IPv6 */
	/* unspecified or not? (RFC 2461 6.3.4) */
	if (advreachable) {
		NTOHL(advreachable);
		if (advreachable <= MAX_REACHABLE_TIME &&
		    ndi->basereachable != advreachable) {
			ndi->basereachable = advreachable;
			ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
			ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
		}
	}
	if (nd_ra->nd_ra_retransmit)
		ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
	if (nd_ra->nd_ra_curhoplimit)
		ndi->chlim = nd_ra->nd_ra_curhoplimit;
	dr = defrtrlist_update(&dr0);
    }

	/*
	 * prefix
	 */
	if (ndopts.nd_opts_pi) {
		struct nd_opt_hdr *pt;
		struct nd_opt_prefix_info *pi = NULL;
		struct nd_prefix pr;
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
		long time_second = time.tv_sec;
#endif

		for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
		     pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
		     pt = (struct nd_opt_hdr *)((caddr_t)pt +
						(pt->nd_opt_len << 3))) {
			if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
				continue;
			pi = (struct nd_opt_prefix_info *)pt;

			if (pi->nd_opt_pi_len != 4) {
				nd6log((LOG_INFO,
				    "nd6_ra_input: invalid option "
				    "len %d for prefix information option, "
				    "ignored\n", pi->nd_opt_pi_len));
				continue;
			}

			if (128 < pi->nd_opt_pi_prefix_len) {
				nd6log((LOG_INFO,
				    "nd6_ra_input: invalid prefix "
				    "len %d for prefix information option, "
				    "ignored\n", pi->nd_opt_pi_prefix_len));
				continue;
			}

			if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
			 || IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
				nd6log((LOG_INFO,
				    "nd6_ra_input: invalid prefix "
				    "%s, ignored\n",
				    ip6_sprintf(&pi->nd_opt_pi_prefix)));
				continue;
			}

			/* aggregatable unicast address, rfc2374 */
			if ((pi->nd_opt_pi_prefix.s6_addr8[0] & 0xe0) == 0x20
			 && pi->nd_opt_pi_prefix_len != 64) {
				nd6log((LOG_INFO,
				    "nd6_ra_input: invalid prefixlen "
				    "%d for rfc2374 prefix %s, ignored\n",
				    pi->nd_opt_pi_prefix_len,
				    ip6_sprintf(&pi->nd_opt_pi_prefix)));
				continue;
			}

			bzero(&pr, sizeof(pr));
			pr.ndpr_prefix.sin6_family = AF_INET6;
			pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
			pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
			pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;

			pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
					      ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
			pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
					    ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
#ifdef MIP6
			pr.ndpr_raf_router = (pi->nd_opt_pi_flags_reserved &
					      ND_OPT_PI_FLAG_ROUTER) ? 1 : 0;
#endif /* MIP6 */
			pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
			pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
			pr.ndpr_pltime =
				ntohl(pi->nd_opt_pi_preferred_time);
			pr.ndpr_lastupdate = time_second;

			if (in6_init_prefix_ltimes(&pr))
				continue; /* prefix lifetime init failed */
#ifdef MIP6
			if (MIP6_IS_MN) {
				if (mip6_prefix_list_update(&saddr6, &pr, dr, m)) {
					mip6log((LOG_ERR,
						 "%s:%d: "
						 "prefix info processing "
						 "failed\n",
						 __FILE__, __LINE__));
					goto freeit;
				}
			}
#endif /* MIP6 */
			(void)prelist_update(&pr, dr, m);
		}
	}

#ifdef MIP6
	if (MIP6_IS_MN) {
		/* check reachability of all routers. */
		mip6_probe_routers();
	}

	/* update home agent list. */
	if ((MIP6_IS_MN || MIP6_IS_HA)
	    && dr
	    && (dr->flags & ND_RA_FLAG_HOME_AGENT)) {
		if (mip6_ha_list_update_hainfo(&mip6_ha_list,
					       dr, ndopts.nd_opts_hai)) {
			mip6log((LOG_ERR,
				 "%s:%d: global HA list update failed\n",
				 __FILE__, __LINE__));
		}
	}
	if (dr == NULL) {
		struct mip6_ha *mha;

		/* the home agent is shutting down. */
		mha = mip6_ha_list_find_withaddr(&mip6_ha_list, &saddr6);
		if (mha) {
			if (mip6_ha_list_remove(&mip6_ha_list, mha)) {
				mip6log((LOG_ERR,
					 "%s:%d: HA entry remove failed.\n",
					 __FILE__, __LINE__));
			}
		}
	}
#endif /* MIP6 */

	/*
	 * MTU
	 */
	if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
		u_int32_t mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);

		/* lower bound */
		if (mtu < IPV6_MMTU) {
			nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
			    "mtu=%d sent from %s, ignoring\n",
			    mtu, ip6_sprintf(&ip6->ip6_src)));
			goto skip;
		}

		/* upper bound */
		if (ndi->maxmtu) {
			if (mtu <= ndi->maxmtu) {
				int change = (ndi->linkmtu != mtu);

				ndi->linkmtu = mtu;
				if (change) /* in6_maxmtu may change */
					in6_setmaxmtu();
			} else {
				nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
				    "mtu=%d sent from %s; "
				    "exceeds maxmtu %d, ignoring\n",
				    mtu, ip6_sprintf(&ip6->ip6_src),
				    ndi->maxmtu));
			}
		} else {