1 /* $OpenBSD: route6.c,v 1.17 2008/06/11 19:00:50 mcbride Exp $ */ 2 /* $KAME: route6.c,v 1.22 2000/12/03 00:54:00 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/param.h> 34 #include <sys/mbuf.h> 35 #include <sys/socket.h> 36 #include <sys/systm.h> 37 38 #include <net/if.h> 39 40 #include <netinet/in.h> 41 #include <netinet6/in6_var.h> 42 #include <netinet/ip6.h> 43 #include <netinet6/ip6_var.h> 44 45 #include <netinet/icmp6.h> 46 47 #if 0 48 static int ip6_rthdr0(struct mbuf *, struct ip6_hdr *, struct ip6_rthdr0 *); 49 #endif 50 51 /* 52 * proto is unused 53 */ 54 55 int 56 route6_input(struct mbuf **mp, int *offp, int proto) 57 { 58 struct ip6_hdr *ip6; 59 struct mbuf *m = *mp; 60 struct ip6_rthdr *rh; 61 int off = *offp, rhlen; 62 63 ip6 = mtod(m, struct ip6_hdr *); 64 IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, sizeof(*rh)); 65 if (rh == NULL) { 66 ip6stat.ip6s_tooshort++; 67 return IPPROTO_DONE; 68 } 69 70 switch (rh->ip6r_type) { 71 #if 0 72 /* 73 * See http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf 74 * for why IPV6_RTHDR_TYPE_0 is banned here. 75 * 76 * We return ICMPv6 parameter problem so that innocent people 77 * (not an attacker) would notice about the use of IPV6_RTHDR_TYPE_0. 78 * Since there's no amplification, and ICMPv6 error will be rate- 79 * controlled, it shouldn't cause any problem. 80 * If you are concerned about this, you may want to use the following 81 * code fragment: 82 * 83 * case IPV6_RTHDR_TYPE_0: 84 * m_freem(m); 85 * return (IPPROTO_DONE); 86 */ 87 case IPV6_RTHDR_TYPE_0: 88 rhlen = (rh->ip6r_len + 1) << 3; 89 if (rh->ip6r_segleft == 0) 90 break; /* Final dst. Just ignore the header. */ 91 /* 92 * note on option length: 93 * maximum rhlen: 2048 94 * max mbuf m_pulldown can handle: MCLBYTES == usually 2048 95 * so, here we are assuming that m_pulldown can handle 96 * rhlen == 2048 case. this may not be a good thing to 97 * assume - we may want to avoid pulling it up altogether. 98 */ 99 IP6_EXTHDR_GET(rh, struct ip6_rthdr *, m, off, rhlen); 100 if (rh == NULL) { 101 ip6stat.ip6s_tooshort++; 102 return IPPROTO_DONE; 103 } 104 if (ip6_rthdr0(m, ip6, (struct ip6_rthdr0 *)rh)) 105 return (IPPROTO_DONE); 106 break; 107 #endif 108 default: 109 /* unknown routing type */ 110 if (rh->ip6r_segleft == 0) { 111 rhlen = (rh->ip6r_len + 1) << 3; 112 break; /* Final dst. Just ignore the header. */ 113 } 114 ip6stat.ip6s_badoptions++; 115 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 116 (caddr_t)&rh->ip6r_type - (caddr_t)ip6); 117 return (IPPROTO_DONE); 118 } 119 120 *offp += rhlen; 121 return (rh->ip6r_nxt); 122 } 123 124 #if 0 125 /* 126 * Type0 routing header processing 127 * 128 * RFC2292 backward compatibility warning: no support for strict/loose bitmap, 129 * as it was dropped between RFC1883 and RFC2460. 130 */ 131 static int 132 ip6_rthdr0(struct mbuf *m, struct ip6_hdr *ip6, struct ip6_rthdr0 *rh0) 133 { 134 int addrs, index; 135 struct in6_addr *nextaddr, tmpaddr; 136 137 if (rh0->ip6r0_segleft == 0) 138 return (0); 139 140 if (rh0->ip6r0_len % 2) { 141 /* 142 * Type 0 routing header can't contain more than 23 addresses. 143 * RFC 2460: this limitation was removed since strict/loose 144 * bitmap field was deleted. 145 */ 146 ip6stat.ip6s_badoptions++; 147 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 148 (caddr_t)&rh0->ip6r0_len - (caddr_t)ip6); 149 return (-1); 150 } 151 152 if ((addrs = rh0->ip6r0_len / 2) < rh0->ip6r0_segleft) { 153 ip6stat.ip6s_badoptions++; 154 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 155 (caddr_t)&rh0->ip6r0_segleft - (caddr_t)ip6); 156 return (-1); 157 } 158 159 index = addrs - rh0->ip6r0_segleft; 160 rh0->ip6r0_segleft--; 161 nextaddr = ((struct in6_addr *)(rh0 + 1)) + index; 162 163 /* 164 * reject invalid addresses. be proactive about malicious use of 165 * IPv4 mapped/compat address. 166 * XXX need more checks? 167 */ 168 if (IN6_IS_ADDR_MULTICAST(nextaddr) || 169 IN6_IS_ADDR_UNSPECIFIED(nextaddr) || 170 IN6_IS_ADDR_V4MAPPED(nextaddr) || 171 IN6_IS_ADDR_V4COMPAT(nextaddr)) { 172 ip6stat.ip6s_badoptions++; 173 goto bad; 174 } 175 if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 176 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst) || 177 IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst) || 178 IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) { 179 ip6stat.ip6s_badoptions++; 180 goto bad; 181 } 182 183 /* 184 * Swap the IPv6 destination address and nextaddr. Forward the packet. 185 */ 186 tmpaddr = *nextaddr; 187 *nextaddr = ip6->ip6_dst; 188 if (IN6_IS_ADDR_LINKLOCAL(nextaddr)) 189 nextaddr->s6_addr16[1] = 0; 190 ip6->ip6_dst = tmpaddr; 191 if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst)) 192 ip6->ip6_dst.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index); 193 194 ip6_forward(m, 1); 195 196 return (-1); /* m would be freed in ip6_forward() */ 197 198 bad: 199 m_freem(m); 200 return (-1); 201 } 202 #endif 203