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] = 136 NLA_POLICY_MASK(NLA_BE32, NF_NAT_RANGE_MASK), 137 }; 138 139 static int nft_nat_validate(const struct nft_ctx *ctx, 140 const struct nft_expr *expr, 141 const struct nft_data **data) 142 { 143 struct nft_nat *priv = nft_expr_priv(expr); 144 int err; 145 146 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT); 147 if (err < 0) 148 return err; 149 150 switch (priv->type) { 151 case NFT_NAT_SNAT: 152 err = nft_chain_validate_hooks(ctx->chain, 153 (1 << NF_INET_POST_ROUTING) | 154 (1 << NF_INET_LOCAL_IN)); 155 break; 156 case NFT_NAT_DNAT: 157 err = nft_chain_validate_hooks(ctx->chain, 158 (1 << NF_INET_PRE_ROUTING) | 159 (1 << NF_INET_LOCAL_OUT)); 160 break; 161 } 162 163 return err; 164 } 165 166 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 167 const struct nlattr * const tb[]) 168 { 169 struct nft_nat *priv = nft_expr_priv(expr); 170 unsigned int alen, plen; 171 u32 family; 172 int err; 173 174 if (tb[NFTA_NAT_TYPE] == NULL || 175 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL && 176 tb[NFTA_NAT_REG_PROTO_MIN] == NULL)) 177 return -EINVAL; 178 179 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) { 180 case NFT_NAT_SNAT: 181 priv->type = NF_NAT_MANIP_SRC; 182 break; 183 case NFT_NAT_DNAT: 184 priv->type = NF_NAT_MANIP_DST; 185 break; 186 default: 187 return -EOPNOTSUPP; 188 } 189 190 if (tb[NFTA_NAT_FAMILY] == NULL) 191 return -EINVAL; 192 193 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY])); 194 if (ctx->family != NFPROTO_INET && ctx->family != family) 195 return -EOPNOTSUPP; 196 197 switch (family) { 198 case NFPROTO_IPV4: 199 alen = sizeof_field(struct nf_nat_range, min_addr.ip); 200 break; 201 case NFPROTO_IPV6: 202 alen = sizeof_field(struct nf_nat_range, min_addr.ip6); 203 break; 204 default: 205 if (tb[NFTA_NAT_REG_ADDR_MIN]) 206 return -EAFNOSUPPORT; 207 break; 208 } 209 priv->family = family; 210 211 if (tb[NFTA_NAT_REG_ADDR_MIN]) { 212 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN], 213 &priv->sreg_addr_min, alen); 214 if (err < 0) 215 return err; 216 217 if (tb[NFTA_NAT_REG_ADDR_MAX]) { 218 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX], 219 &priv->sreg_addr_max, 220 alen); 221 if (err < 0) 222 return err; 223 } else { 224 priv->sreg_addr_max = priv->sreg_addr_min; 225 } 226 227 priv->flags |= NF_NAT_RANGE_MAP_IPS; 228 } 229 230 plen = sizeof_field(struct nf_nat_range, min_proto.all); 231 if (tb[NFTA_NAT_REG_PROTO_MIN]) { 232 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN], 233 &priv->sreg_proto_min, plen); 234 if (err < 0) 235 return err; 236 237 if (tb[NFTA_NAT_REG_PROTO_MAX]) { 238 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX], 239 &priv->sreg_proto_max, 240 plen); 241 if (err < 0) 242 return err; 243 } else { 244 priv->sreg_proto_max = priv->sreg_proto_min; 245 } 246 247 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED; 248 } 249 250 if (tb[NFTA_NAT_FLAGS]) 251 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS])); 252 253 return nf_ct_netns_get(ctx->net, family); 254 } 255 256 static int nft_nat_dump(struct sk_buff *skb, 257 const struct nft_expr *expr, bool reset) 258 { 259 const struct nft_nat *priv = nft_expr_priv(expr); 260 261 switch (priv->type) { 262 case NF_NAT_MANIP_SRC: 263 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT))) 264 goto nla_put_failure; 265 break; 266 case NF_NAT_MANIP_DST: 267 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) 268 goto nla_put_failure; 269 break; 270 } 271 272 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family))) 273 goto nla_put_failure; 274 275 if (priv->sreg_addr_min) { 276 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN, 277 priv->sreg_addr_min) || 278 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX, 279 priv->sreg_addr_max)) 280 goto nla_put_failure; 281 } 282 283 if (priv->sreg_proto_min) { 284 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN, 285 priv->sreg_proto_min) || 286 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX, 287 priv->sreg_proto_max)) 288 goto nla_put_failure; 289 } 290 291 if (priv->flags != 0) { 292 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags))) 293 goto nla_put_failure; 294 } 295 296 return 0; 297 298 nla_put_failure: 299 return -1; 300 } 301 302 static void 303 nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) 304 { 305 const struct nft_nat *priv = nft_expr_priv(expr); 306 307 nf_ct_netns_put(ctx->net, priv->family); 308 } 309 310 static struct nft_expr_type nft_nat_type; 311 static const struct nft_expr_ops nft_nat_ops = { 312 .type = &nft_nat_type, 313 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 314 .eval = nft_nat_eval, 315 .init = nft_nat_init, 316 .destroy = nft_nat_destroy, 317 .dump = nft_nat_dump, 318 .validate = nft_nat_validate, 319 .reduce = NFT_REDUCE_READONLY, 320 }; 321 322 static struct nft_expr_type nft_nat_type __read_mostly = { 323 .name = "nat", 324 .ops = &nft_nat_ops, 325 .policy = nft_nat_policy, 326 .maxattr = NFTA_NAT_MAX, 327 .owner = THIS_MODULE, 328 }; 329 330 #ifdef CONFIG_NF_TABLES_INET 331 static void nft_nat_inet_eval(const struct nft_expr *expr, 332 struct nft_regs *regs, 333 const struct nft_pktinfo *pkt) 334 { 335 const struct nft_nat *priv = nft_expr_priv(expr); 336 337 if (priv->family == nft_pf(pkt) || 338 priv->family == NFPROTO_INET) 339 nft_nat_eval(expr, regs, pkt); 340 } 341 342 static const struct nft_expr_ops nft_nat_inet_ops = { 343 .type = &nft_nat_type, 344 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 345 .eval = nft_nat_inet_eval, 346 .init = nft_nat_init, 347 .destroy = nft_nat_destroy, 348 .dump = nft_nat_dump, 349 .validate = nft_nat_validate, 350 .reduce = NFT_REDUCE_READONLY, 351 }; 352 353 static struct nft_expr_type nft_inet_nat_type __read_mostly = { 354 .name = "nat", 355 .family = NFPROTO_INET, 356 .ops = &nft_nat_inet_ops, 357 .policy = nft_nat_policy, 358 .maxattr = NFTA_NAT_MAX, 359 .owner = THIS_MODULE, 360 }; 361 362 static int nft_nat_inet_module_init(void) 363 { 364 return nft_register_expr(&nft_inet_nat_type); 365 } 366 367 static void nft_nat_inet_module_exit(void) 368 { 369 nft_unregister_expr(&nft_inet_nat_type); 370 } 371 #else 372 static int nft_nat_inet_module_init(void) { return 0; } 373 static void nft_nat_inet_module_exit(void) { } 374 #endif 375 376 static int __init nft_nat_module_init(void) 377 { 378 int ret = nft_nat_inet_module_init(); 379 380 if (ret) 381 return ret; 382 383 ret = nft_register_expr(&nft_nat_type); 384 if (ret) 385 nft_nat_inet_module_exit(); 386 387 return ret; 388 } 389 390 static void __exit nft_nat_module_exit(void) 391 { 392 nft_nat_inet_module_exit(); 393 nft_unregister_expr(&nft_nat_type); 394 } 395 396 module_init(nft_nat_module_init); 397 module_exit(nft_nat_module_exit); 398 399 MODULE_LICENSE("GPL"); 400 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>"); 401 MODULE_ALIAS_NFT_EXPR("nat"); 402 MODULE_DESCRIPTION("Network Address Translation support"); 403