nat64stl.c revision 334836
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 334836 2018-06-08 10:09:30Z 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/pf/pf.h> 59 60#include "nat64stl.h" 61 62#define NAT64_LOOKUP(chain, cmd) \ 63 (struct nat64stl_cfg *)SRV_OBJECT((chain), (cmd)->arg1) 64 65static void 66nat64stl_log(struct pfloghdr *plog, struct mbuf *m, sa_family_t family, 67 uint32_t kidx) 68{ 69 static uint32_t pktid = 0; 70 71 memset(plog, 0, sizeof(*plog)); 72 plog->length = PFLOG_REAL_HDRLEN; 73 plog->af = family; 74 plog->action = PF_NAT; 75 plog->dir = PF_IN; 76 plog->rulenr = htonl(kidx); 77 pktid++; 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(&cfg->base, ip->ip_src.s_addr) != 0 || 96 nat64_check_private_ip4(&cfg->base, 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 nat64_embed_ip4(&cfg->base, ip->ip_src.s_addr, &saddr); 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)); 121 122 /* 123 * NOTE: we expect ipfw_chk() did m_pullup() up to upper level 124 * protocol's headers. Also we skip some checks, that ip6_input(), 125 * ip6_forward(), ip6_fastfwd() and ipfw_chk() already did. 126 */ 127 ip6 = mtod(m, struct ip6_hdr *); 128 /* Check ip6_dst matches configured prefix */ 129 if (bcmp(&ip6->ip6_dst, &cfg->base.prefix6, cfg->base.plen6 / 8) != 0) 130 return (NAT64SKIP); 131 132 if (cfg->base.flags & NAT64_LOG) { 133 logdata = &loghdr; 134 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 135 } else 136 logdata = NULL; 137 return (nat64_do_handle_ip6(m, aaddr, 0, &cfg->base, logdata)); 138} 139 140static int 141nat64stl_handle_icmp6(struct ip_fw_chain *chain, struct nat64stl_cfg *cfg, 142 struct mbuf *m) 143{ 144 struct pfloghdr loghdr, *logdata; 145 struct nat64_counters *stats; 146 struct ip6_hdr *ip6i; 147 struct icmp6_hdr *icmp6; 148 uint32_t tablearg; 149 int hlen, proto; 150 151 hlen = 0; 152 stats = &cfg->base.stats; 153 proto = nat64_getlasthdr(m, &hlen); 154 if (proto != IPPROTO_ICMPV6) { 155 NAT64STAT_INC(stats, dropped); 156 return (NAT64MFREE); 157 } 158 icmp6 = mtodo(m, hlen); 159 switch (icmp6->icmp6_type) { 160 case ICMP6_DST_UNREACH: 161 case ICMP6_PACKET_TOO_BIG: 162 case ICMP6_TIME_EXCEED_TRANSIT: 163 case ICMP6_PARAM_PROB: 164 break; 165 default: 166 NAT64STAT_INC(stats, dropped); 167 return (NAT64MFREE); 168 } 169 hlen += sizeof(struct icmp6_hdr); 170 if (m->m_pkthdr.len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) { 171 NAT64STAT_INC(stats, dropped); 172 return (NAT64MFREE); 173 } 174 if (m->m_len < hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN) 175 m = m_pullup(m, hlen + sizeof(struct ip6_hdr) + ICMP_MINLEN); 176 if (m == NULL) { 177 NAT64STAT_INC(stats, nomem); 178 return (NAT64RETURN); 179 } 180 /* 181 * Use destination address from inner IPv6 header to determine 182 * IPv4 mapped address. 183 */ 184 ip6i = mtodo(m, hlen); 185 if (ipfw_lookup_table(chain, cfg->map64, 186 sizeof(struct in6_addr), &ip6i->ip6_dst, &tablearg) == 0) { 187 m_freem(m); 188 return (NAT64RETURN); 189 } 190 if (cfg->base.flags & NAT64_LOG) { 191 logdata = &loghdr; 192 nat64stl_log(logdata, m, AF_INET6, cfg->no.kidx); 193 } else 194 logdata = NULL; 195 return (nat64_handle_icmp6(m, 0, 196 htonl(TARG_VAL(chain, tablearg, nh4)), 0, &cfg->base, logdata)); 197} 198 199int 200ipfw_nat64stl(struct ip_fw_chain *chain, struct ip_fw_args *args, 201 ipfw_insn *cmd, int *done) 202{ 203 ipfw_insn *icmd; 204 struct nat64stl_cfg *cfg; 205 in_addr_t dst4; 206 uint32_t tablearg; 207 int ret; 208 209 IPFW_RLOCK_ASSERT(chain); 210 211 *done = 0; /* try next rule if not matched */ 212 icmd = cmd + 1; 213 if (cmd->opcode != O_EXTERNAL_ACTION || 214 cmd->arg1 != V_nat64stl_eid || 215 icmd->opcode != O_EXTERNAL_INSTANCE || 216 (cfg = NAT64_LOOKUP(chain, icmd)) == NULL) 217 return (0); 218 219 switch (args->f_id.addr_type) { 220 case 4: 221 dst4 = htonl(args->f_id.dst_ip); 222 ret = ipfw_lookup_table(chain, cfg->map46, sizeof(in_addr_t), 223 &dst4, &tablearg); 224 break; 225 case 6: 226 ret = ipfw_lookup_table(chain, cfg->map64, 227 sizeof(struct in6_addr), &args->f_id.src_ip6, &tablearg); 228 break; 229 default: 230 return (0); 231 } 232 if (ret == 0) { 233 /* 234 * In case when packet is ICMPv6 message from an intermediate 235 * router, the source address of message will not match the 236 * addresses from our map64 table. 237 */ 238 if (args->f_id.proto != IPPROTO_ICMPV6) 239 return (0); 240 241 ret = nat64stl_handle_icmp6(chain, cfg, args->m); 242 } else { 243 if (args->f_id.addr_type == 4) 244 ret = nat64stl_handle_ip4(chain, cfg, args->m, 245 tablearg); 246 else 247 ret = nat64stl_handle_ip6(chain, cfg, args->m, 248 tablearg); 249 } 250 if (ret == NAT64SKIP) 251 return (0); 252 253 *done = 1; /* terminate the search */ 254 if (ret == NAT64MFREE) 255 m_freem(args->m); 256 args->m = NULL; 257 return (IP_FW_DENY); 258} 259 260 261