1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 4 * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org> 5 * Copyright (c) 2012 Intel Corporation 6 */ 7 8 #include <linux/module.h> 9 #include <linux/init.h> 10 #include <linux/skbuff.h> 11 #include <linux/ip.h> 12 #include <linux/string.h> 13 #include <linux/netlink.h> 14 #include <linux/netfilter.h> 15 #include <linux/netfilter_ipv4.h> 16 #include <linux/netfilter/nfnetlink.h> 17 #include <linux/netfilter/nf_tables.h> 18 #include <net/netfilter/nf_conntrack.h> 19 #include <net/netfilter/nf_nat.h> 20 #include <net/netfilter/nf_tables.h> 21 #include <net/ip.h> 22 23 struct nft_nat { 24 u8 sreg_addr_min; 25 u8 sreg_addr_max; 26 u8 sreg_proto_min; 27 u8 sreg_proto_max; 28 enum nf_nat_manip_type type:8; 29 u8 family; 30 u16 flags; 31 }; 32 33 static void nft_nat_setup_addr(struct nf_nat_range2 *range, 34 const struct nft_regs *regs, 35 const struct nft_nat *priv) 36 { 37 switch (priv->family) { 38 case AF_INET: 39 range->min_addr.ip = (__force __be32) 40 regs->data[priv->sreg_addr_min]; 41 range->max_addr.ip = (__force __be32) 42 regs->data[priv->sreg_addr_max]; 43 break; 44 case AF_INET6: 45 memcpy(range->min_addr.ip6, ®s->data[priv->sreg_addr_min], 46 sizeof(range->min_addr.ip6)); 47 memcpy(range->max_addr.ip6, ®s->data[priv->sreg_addr_max], 48 sizeof(range->max_addr.ip6)); 49 break; 50 } 51 } 52 53 static void nft_nat_setup_proto(struct nf_nat_range2 *range, 54 const struct nft_regs *regs, 55 const struct nft_nat *priv) 56 { 57 range->min_proto.all = (__force __be16) 58 nft_reg_load16(®s->data[priv->sreg_proto_min]); 59 range->max_proto.all = (__force __be16) 60 nft_reg_load16(®s->data[priv->sreg_proto_max]); 61 } 62 63 static void nft_nat_setup_netmap(struct nf_nat_range2 *range, 64 const struct nft_pktinfo *pkt, 65 const struct nft_nat *priv) 66 { 67 struct sk_buff *skb = pkt->skb; 68 union nf_inet_addr new_addr; 69 __be32 netmask; 70 int i, len = 0; 71 72 switch (priv->type) { 73 case NFT_NAT_SNAT: 74 if (nft_pf(pkt) == NFPROTO_IPV4) { 75 new_addr.ip = ip_hdr(skb)->saddr; 76 len = sizeof(struct in_addr); 77 } else { 78 new_addr.in6 = ipv6_hdr(skb)->saddr; 79 len = sizeof(struct in6_addr); 80 } 81 break; 82 case NFT_NAT_DNAT: 83 if (nft_pf(pkt) == NFPROTO_IPV4) { 84 new_addr.ip = ip_hdr(skb)->daddr; 85 len = sizeof(struct in_addr); 86 } else { 87 new_addr.in6 = ipv6_hdr(skb)->daddr; 88 len = sizeof(struct in6_addr); 89 } 90 break; 91 } 92 93 for (i = 0; i < len / sizeof(__be32); i++) { 94 netmask = ~(range->min_addr.ip6[i] ^ range->max_addr.ip6[i]); 95 new_addr.ip6[i] &= ~netmask; 96 new_addr.ip6[i] |= range->min_addr.ip6[i] & netmask; 97 } 98 99 range->min_addr = new_addr; 100 range->max_addr = new_addr; 101 } 102 103 static void nft_nat_eval(const struct nft_expr *expr, 104 struct nft_regs *regs, 105 const struct nft_pktinfo *pkt) 106 { 107 const struct nft_nat *priv = nft_expr_priv(expr); 108 enum ip_conntrack_info ctinfo; 109 struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo); 110 struct nf_nat_range2 range; 111 112 memset(&range, 0, sizeof(range)); 113 114 if (priv->sreg_addr_min) { 115 nft_nat_setup_addr(&range, regs, priv); 116 if (priv->flags & NF_NAT_RANGE_NETMAP) 117 nft_nat_setup_netmap(&range, pkt, priv); 118 } 119 120 if (priv->sreg_proto_min) 121 nft_nat_setup_proto(&range, regs, priv); 122 123 range.flags = priv->flags; 124 125 regs->verdict.code = nf_nat_setup_info(ct, &range, priv->type); 126 } 127 128 static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = { 129 [NFTA_NAT_TYPE] = { .type = NLA_U32 }, 130 [NFTA_NAT_FAMILY] = { .type = NLA_U32 }, 131 [NFTA_NAT_REG_ADDR_MIN] = { .type = NLA_U32 }, 132 [NFTA_NAT_REG_ADDR_MAX] = { .type = NLA_U32 }, 133 [NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 }, 134 [NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 }, 135 [NFTA_NAT_FLAGS] = { .type = NLA_U32 }, 136 }; 137 138 static int nft_nat_validate(const struct nft_ctx *ctx, 139 const struct nft_expr *expr, 140 const struct nft_data **data) 141 { 142 struct nft_nat *priv = nft_expr_priv(expr); 143 int err; 144 145 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT); 146 if (err < 0) 147 return err; 148 149 switch (priv->type) { 150 case NFT_NAT_SNAT: 151 err = nft_chain_validate_hooks(ctx->chain, 152 (1 << NF_INET_POST_ROUTING) | 153 (1 << NF_INET_LOCAL_IN)); 154 break; 155 case NFT_NAT_DNAT: 156 err = nft_chain_validate_hooks(ctx->chain, 157 (1 << NF_INET_PRE_ROUTING) | 158 (1 << NF_INET_LOCAL_OUT)); 159 break; 160 } 161 162 return err; 163 } 164 165 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 166 const struct nlattr * const tb[]) 167 { 168 struct nft_nat *priv = nft_expr_priv(expr); 169 unsigned int alen, plen; 170 u32 family; 171 int err; 172 173 if (tb[NFTA_NAT_TYPE] == NULL || 174 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL && 175 tb[NFTA_NAT_REG_PROTO_MIN] == NULL)) 176 return -EINVAL; 177 178 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) { 179 case NFT_NAT_SNAT: 180 priv->type = NF_NAT_MANIP_SRC; 181 break; 182 case NFT_NAT_DNAT: 183 priv->type = NF_NAT_MANIP_DST; 184 break; 185 default: 186 return -EOPNOTSUPP; 187 } 188 189 if (tb[NFTA_NAT_FAMILY] == NULL) 190 return -EINVAL; 191 192 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY])); 193 if (ctx->family != NFPROTO_INET && ctx->family != family) 194 return -EOPNOTSUPP; 195 196 switch (family) { 197 case NFPROTO_IPV4: 198 alen = sizeof_field(struct nf_nat_range, min_addr.ip); 199 break; 200 case NFPROTO_IPV6: 201 alen = sizeof_field(struct nf_nat_range, min_addr.ip6); 202 break; 203 default: 204 if (tb[NFTA_NAT_REG_ADDR_MIN]) 205 return -EAFNOSUPPORT; 206 break; 207 } 208 priv->family = family; 209 210 if (tb[NFTA_NAT_REG_ADDR_MIN]) { 211 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN], 212 &priv->sreg_addr_min, alen); 213 if (err < 0) 214 return err; 215 216 if (tb[NFTA_NAT_REG_ADDR_MAX]) { 217 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX], 218 &priv->sreg_addr_max, 219 alen); 220 if (err < 0) 221 return err; 222 } else { 223 priv->sreg_addr_max = priv->sreg_addr_min; 224 } 225 226 priv->flags |= NF_NAT_RANGE_MAP_IPS; 227 } 228 229 plen = sizeof_field(struct nf_nat_range, min_addr.all); 230 if (tb[NFTA_NAT_REG_PROTO_MIN]) { 231 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN], 232 &priv->sreg_proto_min, plen); 233 if (err < 0) 234 return err; 235 236 if (tb[NFTA_NAT_REG_PROTO_MAX]) { 237 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX], 238 &priv->sreg_proto_max, 239 plen); 240 if (err < 0) 241 return err; 242 } else { 243 priv->sreg_proto_max = priv->sreg_proto_min; 244 } 245 246 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED; 247 } 248 249 if (tb[NFTA_NAT_FLAGS]) { 250 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS])); 251 if (priv->flags & ~NF_NAT_RANGE_MASK) 252 return -EOPNOTSUPP; 253 } 254 255 return nf_ct_netns_get(ctx->net, family); 256 } 257 258 static int nft_nat_dump(struct sk_buff *skb, 259 const struct nft_expr *expr, bool reset) 260 { 261 const struct nft_nat *priv = nft_expr_priv(expr); 262 263 switch (priv->type) { 264 case NF_NAT_MANIP_SRC: 265 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT))) 266 goto nla_put_failure; 267 break; 268 case NF_NAT_MANIP_DST: 269 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) 270 goto nla_put_failure; 271 break; 272 } 273 274 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family))) 275 goto nla_put_failure; 276 277 if (priv->sreg_addr_min) { 278 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN, 279 priv->sreg_addr_min) || 280 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX, 281 priv->sreg_addr_max)) 282 goto nla_put_failure; 283 } 284 285 if (priv->sreg_proto_min) { 286 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN, 287 priv->sreg_proto_min) || 288 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX, 289 priv->sreg_proto_max)) 290 goto nla_put_failure; 291 } 292 293 if (priv->flags != 0) { 294 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags))) 295 goto nla_put_failure; 296 } 297 298 return 0; 299 300 nla_put_failure: 301 return -1; 302 } 303 304 static void 305 nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) 306 { 307 const struct nft_nat *priv = nft_expr_priv(expr); 308 309 nf_ct_netns_put(ctx->net, priv->family); 310 } 311 312 static struct nft_expr_type nft_nat_type; 313 static const struct nft_expr_ops nft_nat_ops = { 314 .type = &nft_nat_type, 315 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 316 .eval = nft_nat_eval, 317 .init = nft_nat_init, 318 .destroy = nft_nat_destroy, 319 .dump = nft_nat_dump, 320 .validate = nft_nat_validate, 321 .reduce = NFT_REDUCE_READONLY, 322 }; 323 324 static struct nft_expr_type nft_nat_type __read_mostly = { 325 .name = "nat", 326 .ops = &nft_nat_ops, 327 .policy = nft_nat_policy, 328 .maxattr = NFTA_NAT_MAX, 329 .owner = THIS_MODULE, 330 }; 331 332 #ifdef CONFIG_NF_TABLES_INET 333 static void nft_nat_inet_eval(const struct nft_expr *expr, 334 struct nft_regs *regs, 335 const struct nft_pktinfo *pkt) 336 { 337 const struct nft_nat *priv = nft_expr_priv(expr); 338 339 if (priv->family == nft_pf(pkt) || 340 priv->family == NFPROTO_INET) 341 nft_nat_eval(expr, regs, pkt); 342 } 343 344 static const struct nft_expr_ops nft_nat_inet_ops = { 345 .type = &nft_nat_type, 346 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 347 .eval = nft_nat_inet_eval, 348 .init = nft_nat_init, 349 .destroy = nft_nat_destroy, 350 .dump = nft_nat_dump, 351 .validate = nft_nat_validate, 352 .reduce = NFT_REDUCE_READONLY, 353 }; 354 355 static struct nft_expr_type nft_inet_nat_type __read_mostly = { 356 .name = "nat", 357 .family = NFPROTO_INET, 358 .ops = &nft_nat_inet_ops, 359 .policy = nft_nat_policy, 360 .maxattr = NFTA_NAT_MAX, 361 .owner = THIS_MODULE, 362 }; 363 364 static int nft_nat_inet_module_init(void) 365 { 366 return nft_register_expr(&nft_inet_nat_type); 367 } 368 369 static void nft_nat_inet_module_exit(void) 370 { 371 nft_unregister_expr(&nft_inet_nat_type); 372 } 373 #else 374 static int nft_nat_inet_module_init(void) { return 0; } 375 static void nft_nat_inet_module_exit(void) { } 376 #endif 377 378 static int __init nft_nat_module_init(void) 379 { 380 int ret = nft_nat_inet_module_init(); 381 382 if (ret) 383 return ret; 384 385 ret = nft_register_expr(&nft_nat_type); 386 if (ret) 387 nft_nat_inet_module_exit(); 388 389 return ret; 390 } 391 392 static void __exit nft_nat_module_exit(void) 393 { 394 nft_nat_inet_module_exit(); 395 nft_unregister_expr(&nft_nat_type); 396 } 397 398 module_init(nft_nat_module_init); 399 module_exit(nft_nat_module_exit); 400 401 MODULE_LICENSE("GPL"); 402 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>"); 403 MODULE_ALIAS_NFT_EXPR("nat"); 404 MODULE_DESCRIPTION("Network Address Translation support"); 405