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      1 /*	$NetBSD: nd6_rtr.c,v 1.149 2020/06/12 11:04:45 roy Exp $	*/
      2 /*	$KAME: nd6_rtr.c,v 1.95 2001/02/07 08:09:47 itojun Exp $	*/
      3 
      4 /*
      5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of the project nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 __KERNEL_RCSID(0, "$NetBSD: nd6_rtr.c,v 1.149 2020/06/12 11:04:45 roy Exp $");
     35 
     36 #ifdef _KERNEL_OPT
     37 #include "opt_net_mpsafe.h"
     38 #endif
     39 
     40 #include <sys/mbuf.h>
     41 #include <sys/syslog.h>
     42 
     43 #include <net/if.h>
     44 
     45 #include <netinet/in.h>
     46 #include <netinet6/in6_var.h>
     47 #include <netinet/ip6.h>
     48 #include <netinet6/nd6.h>
     49 #include <netinet/icmp6.h>
     50 #include <netinet6/icmp6_private.h>
     51 
     52 /*
     53  * Cache the source link layer address of Router Advertisement
     54  * and Solicition messages.
     55  */
     56 void
     57 nd6_rtr_cache(struct mbuf *m, int off, int icmp6len, int icmp6_type)
     58 {
     59 	struct ifnet *ifp;
     60 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
     61 	struct nd_router_solicit *nd_rs;
     62 	struct nd_router_advert *nd_ra;
     63 	struct in6_addr saddr6 = ip6->ip6_src;
     64 	char *lladdr = NULL;
     65 	int lladdrlen = 0;
     66 	union nd_opts ndopts;
     67 	struct psref psref;
     68 	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
     69 
     70 	ifp = m_get_rcvif_psref(m, &psref);
     71 	if (ifp == NULL)
     72 		goto freeit;
     73 
     74 	/* Sanity checks */
     75 	if (ip6->ip6_hlim != 255) {
     76 		nd6log(LOG_ERR, "invalid hlim (%d) from %s to %s on %s\n",
     77 		    ip6->ip6_hlim, IN6_PRINT(ip6bufs, &ip6->ip6_src),
     78 		    IN6_PRINT(ip6bufd, &ip6->ip6_dst), if_name(ifp));
     79 		goto bad;
     80 	}
     81 
     82 	switch (icmp6_type) {
     83 	case ND_ROUTER_SOLICIT:
     84 		/*
     85 		 * Don't update the neighbor cache, if src = ::.
     86 		 * This indicates that the src has no IP address assigned yet.
     87 		 */
     88 		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
     89 			goto freeit;
     90 
     91 		IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off,
     92 		    icmp6len);
     93 		if (nd_rs == NULL) {
     94 			ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
     95 			m_put_rcvif_psref(ifp, &psref);
     96 			return;
     97 		}
     98 
     99 		icmp6len -= sizeof(*nd_rs);
    100 		nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
    101 		break;
    102 	case ND_ROUTER_ADVERT:
    103 		if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
    104 			nd6log(LOG_ERR, "src %s is not link-local\n",
    105 			    IN6_PRINT(ip6bufs, &saddr6));
    106 			goto bad;
    107 		}
    108 
    109 		IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off,
    110 		    icmp6len);
    111 		if (nd_ra == NULL) {
    112 			ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
    113 			m_put_rcvif_psref(ifp, &psref);
    114 			return;
    115 		}
    116 
    117 		icmp6len -= sizeof(*nd_ra);
    118 		nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
    119 		break;
    120 	}
    121 
    122 	if (nd6_options(&ndopts) < 0) {
    123 		nd6log(LOG_INFO, "invalid ND option, ignored\n");
    124 		/* nd6_options have incremented stats */
    125 		goto freeit;
    126 	}
    127 
    128 	if (ndopts.nd_opts_src_lladdr) {
    129 		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
    130 		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
    131 	}
    132 
    133 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
    134 		nd6log(LOG_INFO, "lladdrlen mismatch for %s "
    135 		    "(if %d, %s packet %d)\n",
    136 		    IN6_PRINT(ip6bufs, &saddr6),
    137 		    ifp->if_addrlen,
    138 		    icmp6_type == ND_ROUTER_SOLICIT ? "RS" : "RA",
    139 		    lladdrlen - 2);
    140 		goto bad;
    141 	}
    142 
    143 	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, icmp6_type, 0);
    144 
    145 freeit:
    146 	m_put_rcvif_psref(ifp, &psref);
    147 	m_freem(m);
    148 	return;
    149 
    150 bad:
    151 	ICMP6_STATINC(icmp6_type == ND_ROUTER_SOLICIT ?
    152 	    ICMP6_STAT_BADRS : ICMP6_STAT_BADRA);
    153 	m_put_rcvif_psref(ifp, &psref);
    154 	m_freem(m);
    155 }
    156