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/param.h> 30#include <sys/systm.h> 31#include <sys/counter.h> 32#include <sys/kernel.h> 33#include <sys/lock.h> 34#include <sys/mbuf.h> 35#include <sys/module.h> 36#include <sys/rmlock.h> 37#include <sys/rwlock.h> 38#include <sys/socket.h> 39#include <sys/sysctl.h> 40 41#include <net/if.h> 42#include <net/if_var.h> 43#include <net/if_pflog.h> 44#include <net/pfil.h> 45 46#include <netinet/in.h> 47#include <netinet/ip.h> 48#include <netinet/ip_icmp.h> 49#include <netinet/ip_var.h> 50#include <netinet/ip_fw.h> 51#include <netinet/ip6.h> 52#include <netinet/icmp6.h> 53#include <netinet6/ip_fw_nat64.h> 54 55#include <netpfil/ipfw/ip_fw_private.h> 56#include <netpfil/pf/pf.h> 57 58#include "nat64stl.h" 59 60#define NAT64_LOOKUP(chain, cmd) \ 61 (struct nat64stl_cfg *)SRV_OBJECT((chain), (cmd)->arg1) 62 63static void 64nat64stl_log(struct pfloghdr *plog, struct mbuf *m, sa_family_t family, 65 uint32_t kidx) 66{ 67 static uint32_t pktid = 0; 68 69 memset(plog, 0, sizeof(*plog)); 70 plog->length = PFLOG_HDRLEN; 71 plog->af = family; 72 plog->action = PF_NAT; 73 plog->dir = PF_IN; 74 plog->rulenr = htonl(kidx); 75 pktid++; 76 plog->subrulenr = htonl(pktid); 77 plog->ruleset[0] = '\0'; 78 strlcpy(plog->ifname, "NAT64STL", sizeof(plog->ifname)); 79 ipfw_bpf_mtap2(plog, PFLOG_HDRLEN, m); 80} 81 82static int 83nat64stl_handle_ip4(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 84 struct mbuf *m, uint32_t tablearg) 85{ 86 struct pfloghdr loghdr, *logdata; 87 struct in6_addr saddr, daddr; 88 struct ip *ip; 89 90 ip = mtod(m, struct ip*); 91 if (nat64_check_ip4(ip->ip_src.s_addr) != 0 || 92 nat64_check_ip4(ip->ip_dst.s_addr) != 0 || 93 nat64_check_private_ip4(&cfg->base, ip->ip_src.s_addr) != 0 || 94 nat64_check_private_ip4(&cfg->base, ip->ip_dst.s_addr) != 0) 95 return (NAT64SKIP); 96 97 daddr = TARG_VAL(chain, tablearg, nh6); 98 if (nat64_check_ip6(&daddr) != 0) 99 return (NAT64MFREE); 100 101 saddr = cfg->base.plat_prefix; 102 nat64_embed_ip4(&saddr, cfg->base.plat_plen, ip->ip_src.s_addr); 103 if (cfg->base.flags & NAT64_LOG) { 104 logdata = &loghdr; 105 nat64stl_log(logdata, m, AF_INET, cfg->no.kidx); 106 } else 107 logdata = NULL; 108 return (nat64_do_handle_ip4(m, &saddr, &daddr, 0, &cfg->base, 109 logdata)); 110} 111 112static int 113nat64stl_handle_ip6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 114 struct mbuf *m, uint32_t tablearg) 115{ 116 struct pfloghdr loghdr, *logdata; 117 struct ip6_hdr *ip6; 118 uint32_t aaddr; 119 120 aaddr = htonl(TARG_VAL(chain, tablearg, nh4)); 121 if (nat64_check_private_ip4(&cfg->base, aaddr) != 0) { 122 NAT64STAT_INC(&cfg->base.stats, dropped); 123 return (NAT64MFREE); 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 (memcmp(&ip6->ip6_dst, &cfg->base.plat_prefix, 133 cfg->base.plat_plen / 8) != 0) 134 return (NAT64SKIP); 135 136 if (cfg->base.flags & NAT64_LOG) { 137 logdata = &loghdr; 138 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 139 } else 140 logdata = NULL; 141 return (nat64_do_handle_ip6(m, aaddr, 0, &cfg->base, logdata)); 142} 143 144static int 145nat64stl_handle_icmp6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 146 struct mbuf *m) 147{ 148 struct pfloghdr loghdr, *logdata; 149 struct nat64_counters *stats; 150 struct ip6_hdr *ip6i; 151 struct icmp6_hdr *icmp6; 152 uint32_t tablearg; 153 int hlen, proto; 154 155 hlen = 0; 156 stats = &cfg->base.stats; 157 proto = nat64_getlasthdr(m, &hlen); 158 if (proto != IPPROTO_ICMPV6) { 159 NAT64STAT_INC(stats, dropped); 160 return (NAT64MFREE); 161 } 162 icmp6 = mtodo(m, hlen); 163 switch (icmp6->icmp6_type) { 164 case ICMP6_DST_UNREACH: 165 case ICMP6_PACKET_TOO_BIG: 166 case ICMP6_TIME_EXCEED_TRANSIT: 167 case ICMP6_PARAM_PROB: 168 break; 169 default: 170 NAT64STAT_INC(stats, dropped); 171 return (NAT64MFREE); 172 } 173 hlen += sizeof(struct icmp6_hdr); 174 if (m->m_pkthdr.len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) { 175 NAT64STAT_INC(stats, dropped); 176 return (NAT64MFREE); 177 } 178 if (m->m_len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) 179 m = m_pullup(m, hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN); 180 if (m == NULL) { 181 NAT64STAT_INC(stats, nomem); 182 return (NAT64RETURN); 183 } 184 /* 185 * Use destination address from inner IPv6 header to determine 186 * IPv4 mapped address. 187 */ 188 ip6i = mtodo(m, hlen); 189 if (ipfw_lookup_table(chain, cfg->map64, 190 sizeof(struct in6_addr), &ip6i->ip6_dst, &tablearg) == 0) { 191 m_freem(m); 192 return (NAT64RETURN); 193 } 194 if (cfg->base.flags & NAT64_LOG) { 195 logdata = &loghdr; 196 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 197 } else 198 logdata = NULL; 199 return (nat64_handle_icmp6(m, 0, 200 htonl(TARG_VAL(chain, tablearg, nh4)), 0, &cfg->base, logdata)); 201} 202 203int 204ipfw_nat64stl(struct ip_fw_chain *chain, struct ip_fw_args *args, 205 ipfw_insn *cmd, int *done) 206{ 207 ipfw_insn *icmd; 208 struct nat64stl_cfg *cfg; 209 in_addr_t dst4; 210 uint32_t tablearg; 211 int ret; 212 213 IPFW_RLOCK_ASSERT(chain); 214 215 *done = 0; /* try next rule if not matched */ 216 icmd = cmd + 1; 217 if (cmd->opcode != O_EXTERNAL_ACTION || 218 cmd->arg1 != V_nat64stl_eid || 219 icmd->opcode != O_EXTERNAL_INSTANCE || 220 (cfg = NAT64_LOOKUP(chain, icmd)) == NULL) 221 return (0); 222 223 switch (args->f_id.addr_type) { 224 case 4: 225 dst4 = htonl(args->f_id.dst_ip); 226 ret = ipfw_lookup_table(chain, cfg->map46, sizeof(in_addr_t), 227 &dst4, &tablearg); 228 break; 229 case 6: 230 ret = ipfw_lookup_table(chain, cfg->map64, 231 sizeof(struct in6_addr), &args->f_id.src_ip6, &tablearg); 232 break; 233 default: 234 return (0); 235 } 236 if (ret == 0) { 237 /* 238 * In case when packet is ICMPv6 message from an intermediate 239 * router, the source address of message will not match the 240 * addresses from our map64 table. 241 */ 242 if (args->f_id.proto != IPPROTO_ICMPV6) 243 return (0); 244 245 ret = nat64stl_handle_icmp6(chain, cfg, args->m); 246 } else { 247 if (args->f_id.addr_type == 4) 248 ret = nat64stl_handle_ip4(chain, cfg, args->m, 249 tablearg); 250 else 251 ret = nat64stl_handle_ip6(chain, cfg, args->m, 252 tablearg); 253 } 254 if (ret == NAT64SKIP) 255 return (0); 256 257 *done = 1; /* terminate the search */ 258 if (ret == NAT64MFREE) 259 m_freem(args->m); 260 args->m = NULL; 261 return (IP_FW_NAT64); 262} 263