1 /*- 2 * Copyright (c) 2015-2016 Yandex LLC 3 * Copyright (c) 2015-2016 Andrey V. Elsukov <ae@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/counter.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/mbuf.h> 37 #include <sys/module.h> 38 #include <sys/rmlock.h> 39 #include <sys/rwlock.h> 40 #include <sys/socket.h> 41 #include <sys/sysctl.h> 42 43 #include <net/if.h> 44 #include <net/if_var.h> 45 #include <net/if_pflog.h> 46 #include <net/pfil.h> 47 48 #include <netinet/in.h> 49 #include <netinet/ip.h> 50 #include <netinet/ip_icmp.h> 51 #include <netinet/ip_var.h> 52 #include <netinet/ip_fw.h> 53 #include <netinet/ip6.h> 54 #include <netinet/icmp6.h> 55 #include <netinet6/ip_fw_nat64.h> 56 57 #include <netpfil/ipfw/ip_fw_private.h> 58 #include <netpfil/ipfw/nat64/ip_fw_nat64.h> 59 #include <netpfil/ipfw/nat64/nat64_translate.h> 60 #include <netpfil/ipfw/nat64/nat64stl.h> 61 #include <netpfil/pf/pf.h> 62 63 #define NAT64_LOOKUP(chain, cmd) \ 64 (struct nat64stl_cfg *)SRV_OBJECT((chain), (cmd)->arg1) 65 66 static void 67 nat64stl_log(struct pfloghdr *plog, struct mbuf *m, sa_family_t family, 68 uint32_t kidx) 69 { 70 static uint32_t pktid = 0; 71 72 memset(plog, 0, sizeof(*plog)); 73 plog->length = PFLOG_REAL_HDRLEN; 74 plog->af = family; 75 plog->action = PF_NAT; 76 plog->dir = PF_IN; 77 plog->rulenr = htonl(kidx); 78 pktid++; 79 plog->subrulenr = htonl(pktid); 80 plog->ruleset[0] = '\0'; 81 strlcpy(plog->ifname, "NAT64STL", sizeof(plog->ifname)); 82 ipfw_bpf_mtap2(plog, PFLOG_HDRLEN, m); 83 } 84 85 static int 86 nat64stl_handle_ip4(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 87 struct mbuf *m, uint32_t tablearg) 88 { 89 struct pfloghdr loghdr, *logdata; 90 struct in6_addr saddr, daddr; 91 struct ip *ip; 92 93 ip = mtod(m, struct ip*); 94 if (nat64_check_ip4(ip->ip_src.s_addr) != 0 || 95 nat64_check_ip4(ip->ip_dst.s_addr) != 0 || 96 nat64_check_private_ip4(ip->ip_src.s_addr) != 0 || 97 nat64_check_private_ip4(ip->ip_dst.s_addr) != 0) 98 return (NAT64SKIP); 99 100 daddr = TARG_VAL(chain, tablearg, nh6); 101 if (nat64_check_ip6(&daddr) != 0) 102 return (NAT64MFREE); 103 saddr = cfg->prefix6; 104 nat64_set_ip4(&saddr, ip->ip_src.s_addr); 105 106 if (cfg->flags & NAT64_LOG) { 107 logdata = &loghdr; 108 nat64stl_log(logdata, m, AF_INET, cfg->no.kidx); 109 } else 110 logdata = NULL; 111 return (nat64_do_handle_ip4(m, &saddr, &daddr, 0, &cfg->stats, 112 logdata)); 113 } 114 115 static int 116 nat64stl_handle_ip6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 117 struct mbuf *m, uint32_t tablearg) 118 { 119 struct pfloghdr loghdr, *logdata; 120 struct ip6_hdr *ip6; 121 uint32_t aaddr; 122 123 aaddr = htonl(TARG_VAL(chain, tablearg, nh4)); 124 125 /* 126 * NOTE: we expect ipfw_chk() did m_pullup() up to upper level 127 * protocol's headers. Also we skip some checks, that ip6_input(), 128 * ip6_forward(), ip6_fastfwd() and ipfw_chk() already did. 129 */ 130 ip6 = mtod(m, struct ip6_hdr *); 131 /* Check ip6_dst matches configured prefix */ 132 if (bcmp(&ip6->ip6_dst, &cfg->prefix6, cfg->plen6 / 8) != 0) 133 return (NAT64SKIP); 134 135 if (cfg->flags & NAT64_LOG) { 136 logdata = &loghdr; 137 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 138 } else 139 logdata = NULL; 140 return (nat64_do_handle_ip6(m, aaddr, 0, &cfg->stats, logdata)); 141 } 142 143 static int 144 nat64stl_handle_icmp6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 145 struct mbuf *m) 146 { 147 struct pfloghdr loghdr, *logdata; 148 nat64_stats_block *stats; 149 struct ip6_hdr *ip6i; 150 struct icmp6_hdr *icmp6; 151 uint32_t tablearg; 152 int hlen, proto; 153 154 hlen = 0; 155 stats = &cfg->stats; 156 proto = nat64_getlasthdr(m, &hlen); 157 if (proto != IPPROTO_ICMPV6) { 158 NAT64STAT_INC(stats, dropped); 159 return (NAT64MFREE); 160 } 161 icmp6 = mtodo(m, hlen); 162 switch (icmp6->icmp6_type) { 163 case ICMP6_DST_UNREACH: 164 case ICMP6_PACKET_TOO_BIG: 165 case ICMP6_TIME_EXCEED_TRANSIT: 166 case ICMP6_PARAM_PROB: 167 break; 168 default: 169 NAT64STAT_INC(stats, dropped); 170 return (NAT64MFREE); 171 } 172 hlen += sizeof(struct icmp6_hdr); 173 if (m->m_pkthdr.len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) { 174 NAT64STAT_INC(stats, dropped); 175 return (NAT64MFREE); 176 } 177 if (m->m_len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) 178 m = m_pullup(m, hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN); 179 if (m == NULL) { 180 NAT64STAT_INC(stats, nomem); 181 return (NAT64RETURN); 182 } 183 /* 184 * Use destination address from inner IPv6 header to determine 185 * IPv4 mapped address. 186 */ 187 ip6i = mtodo(m, hlen); 188 if (ipfw_lookup_table(chain, cfg->map64, 189 sizeof(struct in6_addr), &ip6i->ip6_dst, &tablearg) == 0) { 190 m_freem(m); 191 return (NAT64RETURN); 192 } 193 if (cfg->flags & NAT64_LOG) { 194 logdata = &loghdr; 195 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 196 } else 197 logdata = NULL; 198 return (nat64_handle_icmp6(m, 0, 199 htonl(TARG_VAL(chain, tablearg, nh4)), 0, stats, logdata)); 200 } 201 202 int 203 ipfw_nat64stl(struct ip_fw_chain *chain, struct ip_fw_args *args, 204 ipfw_insn *cmd, int *done) 205 { 206 ipfw_insn *icmd; 207 struct nat64stl_cfg *cfg; 208 in_addr_t dst4; 209 uint32_t tablearg; 210 int ret; 211 212 IPFW_RLOCK_ASSERT(chain); 213 214 *done = 0; /* try next rule if not matched */ 215 icmd = cmd + 1; 216 if (cmd->opcode != O_EXTERNAL_ACTION || 217 cmd->arg1 != V_nat64stl_eid || 218 icmd->opcode != O_EXTERNAL_INSTANCE || 219 (cfg = NAT64_LOOKUP(chain, icmd)) == NULL) 220 return (0); 221 222 switch (args->f_id.addr_type) { 223 case 4: 224 dst4 = htonl(args->f_id.dst_ip); 225 ret = ipfw_lookup_table(chain, cfg->map46, sizeof(in_addr_t), 226 &dst4, &tablearg); 227 break; 228 case 6: 229 ret = ipfw_lookup_table(chain, cfg->map64, 230 sizeof(struct in6_addr), &args->f_id.src_ip6, &tablearg); 231 break; 232 default: 233 return (0); 234 } 235 if (ret == 0) { 236 /* 237 * In case when packet is ICMPv6 message from an intermediate 238 * router, the source address of message will not match the 239 * addresses from our map64 table. 240 */ 241 if (args->f_id.proto != IPPROTO_ICMPV6) 242 return (0); 243 244 ret = nat64stl_handle_icmp6(chain, cfg, args->m); 245 } else { 246 if (args->f_id.addr_type == 4) 247 ret = nat64stl_handle_ip4(chain, cfg, args->m, 248 tablearg); 249 else 250 ret = nat64stl_handle_ip6(chain, cfg, args->m, 251 tablearg); 252 } 253 if (ret == NAT64SKIP) 254 return (0); 255 256 *done = 1; /* terminate the search */ 257 if (ret == NAT64MFREE) 258 m_freem(args->m); 259 args->m = NULL; 260 return (IP_FW_DENY); 261 } 262 263 264