nat64stl.c revision 316446
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: stable/11/sys/netpfil/ipfw/nat64/nat64stl.c 316446 2017-04-03 08:50:54Z ae $"); 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 66static void 67nat64stl_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 plog->subrulenr = htonl(++pktid); 79 plog->ruleset[0] = '\0'; 80 strlcpy(plog->ifname, "NAT64STL", sizeof(plog->ifname)); 81 ipfw_bpf_mtap2(plog, PFLOG_HDRLEN, m); 82} 83 84static int 85nat64stl_handle_ip4(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 86 struct mbuf *m, uint32_t tablearg) 87{ 88 struct pfloghdr loghdr, *logdata; 89 struct in6_addr saddr, daddr; 90 struct ip *ip; 91 92 ip = mtod(m, struct ip*); 93 if (nat64_check_ip4(ip->ip_src.s_addr) != 0 || 94 nat64_check_ip4(ip->ip_dst.s_addr) != 0 || 95 nat64_check_private_ip4(ip->ip_src.s_addr) != 0 || 96 nat64_check_private_ip4(ip->ip_dst.s_addr) != 0) 97 return (NAT64SKIP); 98 99 daddr = TARG_VAL(chain, tablearg, nh6); 100 if (nat64_check_ip6(&daddr) != 0) 101 return (NAT64MFREE); 102 saddr = cfg->prefix6; 103 nat64_set_ip4(&saddr, ip->ip_src.s_addr); 104 105 if (cfg->flags & NAT64_LOG) { 106 logdata = &loghdr; 107 nat64stl_log(logdata, m, AF_INET, cfg->no.kidx); 108 } else 109 logdata = NULL; 110 return (nat64_do_handle_ip4(m, &saddr, &daddr, 0, &cfg->stats, 111 logdata)); 112} 113 114static int 115nat64stl_handle_ip6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 116 struct mbuf *m, uint32_t tablearg) 117{ 118 struct pfloghdr loghdr, *logdata; 119 struct ip6_hdr *ip6; 120 uint32_t aaddr; 121 122 aaddr = htonl(TARG_VAL(chain, tablearg, nh4)); 123 124 /* 125 * NOTE: we expect ipfw_chk() did m_pullup() up to upper level 126 * protocol's headers. Also we skip some checks, that ip6_input(), 127 * ip6_forward(), ip6_fastfwd() and ipfw_chk() already did. 128 */ 129 ip6 = mtod(m, struct ip6_hdr *); 130 /* Check ip6_dst matches configured prefix */ 131 if (bcmp(&ip6->ip6_dst, &cfg->prefix6, cfg->plen6 / 8) != 0) 132 return (NAT64SKIP); 133 134 if (cfg->flags & NAT64_LOG) { 135 logdata = &loghdr; 136 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 137 } else 138 logdata = NULL; 139 return (nat64_do_handle_ip6(m, aaddr, 0, &cfg->stats, logdata)); 140} 141 142static int 143nat64stl_handle_icmp6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 144 struct mbuf *m) 145{ 146 struct pfloghdr loghdr, *logdata; 147 nat64_stats_block *stats; 148 struct ip6_hdr *ip6i; 149 struct icmp6_hdr *icmp6; 150 uint32_t tablearg; 151 int hlen, proto; 152 153 hlen = 0; 154 stats = &cfg->stats; 155 proto = nat64_getlasthdr(m, &hlen); 156 if (proto != IPPROTO_ICMPV6) { 157 NAT64STAT_INC(stats, dropped); 158 return (NAT64MFREE); 159 } 160 icmp6 = mtodo(m, hlen); 161 switch (icmp6->icmp6_type) { 162 case ICMP6_DST_UNREACH: 163 case ICMP6_PACKET_TOO_BIG: 164 case ICMP6_TIME_EXCEED_TRANSIT: 165 case ICMP6_PARAM_PROB: 166 break; 167 default: 168 NAT64STAT_INC(stats, dropped); 169 return (NAT64MFREE); 170 } 171 hlen += sizeof(struct icmp6_hdr); 172 if (m->m_pkthdr.len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) { 173 NAT64STAT_INC(stats, dropped); 174 return (NAT64MFREE); 175 } 176 if (m->m_len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) 177 m = m_pullup(m, hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN); 178 if (m == NULL) { 179 NAT64STAT_INC(stats, nomem); 180 return (NAT64RETURN); 181 } 182 /* 183 * Use destination address from inner IPv6 header to determine 184 * IPv4 mapped address. 185 */ 186 ip6i = mtodo(m, hlen); 187 if (ipfw_lookup_table(chain, cfg->map64, 188 sizeof(struct in6_addr), &ip6i->ip6_dst, &tablearg) == 0) { 189 m_freem(m); 190 return (NAT64RETURN); 191 } 192 if (cfg->flags & NAT64_LOG) { 193 logdata = &loghdr; 194 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 195 } else 196 logdata = NULL; 197 return (nat64_handle_icmp6(m, 0, 198 htonl(TARG_VAL(chain, tablearg, nh4)), 0, stats, logdata)); 199} 200 201int 202ipfw_nat64stl(struct ip_fw_chain *chain, struct ip_fw_args *args, 203 ipfw_insn *cmd, int *done) 204{ 205 ipfw_insn *icmd; 206 struct nat64stl_cfg *cfg; 207 in_addr_t dst4; 208 uint32_t tablearg; 209 int ret; 210 211 IPFW_RLOCK_ASSERT(chain); 212 213 *done = 0; /* try next rule if not matched */ 214 icmd = cmd + 1; 215 if (cmd->opcode != O_EXTERNAL_ACTION || 216 cmd->arg1 != V_nat64stl_eid || 217 icmd->opcode != O_EXTERNAL_INSTANCE || 218 (cfg = NAT64_LOOKUP(chain, icmd)) == NULL) 219 return (0); 220 221 switch (args->f_id.addr_type) { 222 case 4: 223 dst4 = htonl(args->f_id.dst_ip); 224 ret = ipfw_lookup_table(chain, cfg->map46, sizeof(in_addr_t), 225 &dst4, &tablearg); 226 break; 227 case 6: 228 ret = ipfw_lookup_table(chain, cfg->map64, 229 sizeof(struct in6_addr), &args->f_id.src_ip6, &tablearg); 230 break; 231 default: 232 return (0); 233 } 234 if (ret == 0) { 235 /* 236 * In case when packet is ICMPv6 message from an intermediate 237 * router, the source address of message will not match the 238 * addresses from our map64 table. 239 */ 240 if (args->f_id.proto != IPPROTO_ICMPV6) 241 return (0); 242 243 ret = nat64stl_handle_icmp6(chain, cfg, args->m); 244 } else { 245 if (args->f_id.addr_type == 4) 246 ret = nat64stl_handle_ip4(chain, cfg, args->m, 247 tablearg); 248 else 249 ret = nat64stl_handle_ip6(chain, cfg, args->m, 250 tablearg); 251 } 252 if (ret == NAT64SKIP) 253 return (0); 254 255 *done = 1; /* terminate the search */ 256 if (ret == NAT64MFREE) 257 m_freem(args->m); 258 args->m = NULL; 259 return (IP_FW_DENY); 260} 261 262 263