1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2015-2019 Yandex LLC 5 * Copyright (c) 2015-2019 Andrey V. Elsukov <ae@FreeBSD.org> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 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 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/counter.h> 33 #include <sys/kernel.h> 34 #include <sys/lock.h> 35 #include <sys/mbuf.h> 36 #include <sys/module.h> 37 #include <sys/rmlock.h> 38 #include <sys/rwlock.h> 39 #include <sys/socket.h> 40 #include <sys/sysctl.h> 41 42 #include <net/if.h> 43 #include <net/if_var.h> 44 #include <net/if_pflog.h> 45 #include <net/pfil.h> 46 47 #include <netinet/in.h> 48 #include <netinet/ip.h> 49 #include <netinet/ip_icmp.h> 50 #include <netinet/ip_var.h> 51 #include <netinet/ip_fw.h> 52 #include <netinet/ip6.h> 53 #include <netinet/icmp6.h> 54 #include <netinet6/ip_fw_nat64.h> 55 56 #include <netpfil/ipfw/ip_fw_private.h> 57 #include <netpfil/pf/pf.h> 58 59 #include "nat64stl.h" 60 61 #define NAT64_LOOKUP(chain, cmd) \ 62 (struct nat64stl_cfg *)SRV_OBJECT((chain), (cmd)->arg1) 63 64 static void 65 nat64stl_log(struct pfloghdr *plog, struct mbuf *m, sa_family_t family, 66 uint32_t kidx) 67 { 68 static uint32_t pktid = 0; 69 70 memset(plog, 0, sizeof(*plog)); 71 plog->length = PFLOG_HDRLEN; 72 plog->af = family; 73 plog->action = PF_NAT; 74 plog->dir = PF_IN; 75 plog->rulenr = htonl(kidx); 76 pktid++; 77 plog->subrulenr = htonl(pktid); 78 plog->ruleset[0] = '\0'; 79 strlcpy(plog->ifname, "NAT64STL", sizeof(plog->ifname)); 80 ipfw_bpf_mtap2(plog, PFLOG_HDRLEN, m); 81 } 82 83 static int 84 nat64stl_handle_ip4(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 85 struct mbuf *m, uint32_t tablearg) 86 { 87 struct pfloghdr loghdr, *logdata; 88 struct in6_addr saddr, daddr; 89 struct ip *ip; 90 91 ip = mtod(m, struct ip*); 92 if (nat64_check_ip4(ip->ip_src.s_addr) != 0 || 93 nat64_check_ip4(ip->ip_dst.s_addr) != 0 || 94 nat64_check_private_ip4(&cfg->base, ip->ip_src.s_addr) != 0 || 95 nat64_check_private_ip4(&cfg->base, ip->ip_dst.s_addr) != 0) 96 return (NAT64SKIP); 97 98 daddr = TARG_VAL(chain, tablearg, nh6); 99 if (nat64_check_ip6(&daddr) != 0) 100 return (NAT64MFREE); 101 102 saddr = cfg->base.plat_prefix; 103 nat64_embed_ip4(&saddr, cfg->base.plat_plen, ip->ip_src.s_addr); 104 if (cfg->base.flags & NAT64_LOG) { 105 logdata = &loghdr; 106 nat64stl_log(logdata, m, AF_INET, cfg->no.kidx); 107 } else 108 logdata = NULL; 109 return (nat64_do_handle_ip4(m, &saddr, &daddr, 0, &cfg->base, 110 logdata)); 111 } 112 113 static int 114 nat64stl_handle_ip6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 115 struct mbuf *m, uint32_t tablearg) 116 { 117 struct pfloghdr loghdr, *logdata; 118 struct ip6_hdr *ip6; 119 uint32_t aaddr; 120 121 aaddr = htonl(TARG_VAL(chain, tablearg, nh4)); 122 if (nat64_check_private_ip4(&cfg->base, aaddr) != 0) { 123 NAT64STAT_INC(&cfg->base.stats, dropped); 124 return (NAT64MFREE); 125 } 126 /* 127 * NOTE: we expect ipfw_chk() did m_pullup() up to upper level 128 * protocol's headers. Also we skip some checks, that ip6_input(), 129 * ip6_forward(), ip6_fastfwd() and ipfw_chk() already did. 130 */ 131 ip6 = mtod(m, struct ip6_hdr *); 132 /* Check ip6_dst matches configured prefix */ 133 if (memcmp(&ip6->ip6_dst, &cfg->base.plat_prefix, 134 cfg->base.plat_plen / 8) != 0) 135 return (NAT64SKIP); 136 137 if (cfg->base.flags & NAT64_LOG) { 138 logdata = &loghdr; 139 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 140 } else 141 logdata = NULL; 142 return (nat64_do_handle_ip6(m, aaddr, 0, &cfg->base, logdata)); 143 } 144 145 static int 146 nat64stl_handle_icmp6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 147 struct mbuf *m) 148 { 149 struct pfloghdr loghdr, *logdata; 150 struct nat64_counters *stats; 151 struct ip6_hdr *ip6i; 152 struct icmp6_hdr *icmp6; 153 uint32_t tablearg; 154 int hlen, proto; 155 156 hlen = 0; 157 stats = &cfg->base.stats; 158 proto = nat64_getlasthdr(m, &hlen); 159 if (proto != IPPROTO_ICMPV6) { 160 NAT64STAT_INC(stats, dropped); 161 return (NAT64MFREE); 162 } 163 icmp6 = mtodo(m, hlen); 164 switch (icmp6->icmp6_type) { 165 case ICMP6_DST_UNREACH: 166 case ICMP6_PACKET_TOO_BIG: 167 case ICMP6_TIME_EXCEED_TRANSIT: 168 case ICMP6_PARAM_PROB: 169 break; 170 default: 171 NAT64STAT_INC(stats, dropped); 172 return (NAT64MFREE); 173 } 174 hlen += sizeof(struct icmp6_hdr); 175 if (m->m_pkthdr.len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) { 176 NAT64STAT_INC(stats, dropped); 177 return (NAT64MFREE); 178 } 179 if (m->m_len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) 180 m = m_pullup(m, hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN); 181 if (m == NULL) { 182 NAT64STAT_INC(stats, nomem); 183 return (NAT64RETURN); 184 } 185 /* 186 * Use destination address from inner IPv6 header to determine 187 * IPv4 mapped address. 188 */ 189 ip6i = mtodo(m, hlen); 190 if (ipfw_lookup_table(chain, cfg->map64, 191 sizeof(struct in6_addr), &ip6i->ip6_dst, &tablearg) == 0) { 192 m_freem(m); 193 return (NAT64RETURN); 194 } 195 if (cfg->base.flags & NAT64_LOG) { 196 logdata = &loghdr; 197 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 198 } else 199 logdata = NULL; 200 return (nat64_handle_icmp6(m, 0, 201 htonl(TARG_VAL(chain, tablearg, nh4)), 0, &cfg->base, logdata)); 202 } 203 204 int 205 ipfw_nat64stl(struct ip_fw_chain *chain, struct ip_fw_args *args, 206 ipfw_insn *cmd, int *done) 207 { 208 ipfw_insn *icmd; 209 struct nat64stl_cfg *cfg; 210 in_addr_t dst4; 211 uint32_t tablearg; 212 int ret; 213 214 IPFW_RLOCK_ASSERT(chain); 215 216 *done = 0; /* try next rule if not matched */ 217 icmd = cmd + 1; 218 if (cmd->opcode != O_EXTERNAL_ACTION || 219 cmd->arg1 != V_nat64stl_eid || 220 icmd->opcode != O_EXTERNAL_INSTANCE || 221 (cfg = NAT64_LOOKUP(chain, icmd)) == NULL) 222 return (0); 223 224 switch (args->f_id.addr_type) { 225 case 4: 226 dst4 = htonl(args->f_id.dst_ip); 227 ret = ipfw_lookup_table(chain, cfg->map46, sizeof(in_addr_t), 228 &dst4, &tablearg); 229 break; 230 case 6: 231 ret = ipfw_lookup_table(chain, cfg->map64, 232 sizeof(struct in6_addr), &args->f_id.src_ip6, &tablearg); 233 break; 234 default: 235 return (0); 236 } 237 if (ret == 0) { 238 /* 239 * In case when packet is ICMPv6 message from an intermediate 240 * router, the source address of message will not match the 241 * addresses from our map64 table. 242 */ 243 if (args->f_id.proto != IPPROTO_ICMPV6) 244 return (0); 245 246 ret = nat64stl_handle_icmp6(chain, cfg, args->m); 247 } else { 248 if (args->f_id.addr_type == 4) 249 ret = nat64stl_handle_ip4(chain, cfg, args->m, 250 tablearg); 251 else 252 ret = nat64stl_handle_ip6(chain, cfg, args->m, 253 tablearg); 254 } 255 if (ret == NAT64SKIP) 256 return (0); 257 258 *done = 1; /* terminate the search */ 259 if (ret == NAT64MFREE) 260 m_freem(args->m); 261 args->m = NULL; 262 return (IP_FW_NAT64); 263 } 264