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 return -EAFNOSUPPORT; 205 } 206 priv->family = family; 207 208 if (tb[NFTA_NAT_REG_ADDR_MIN]) { 209 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN], 210 &priv->sreg_addr_min, alen); 211 if (err < 0) 212 return err; 213 214 if (tb[NFTA_NAT_REG_ADDR_MAX]) { 215 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX], 216 &priv->sreg_addr_max, 217 alen); 218 if (err < 0) 219 return err; 220 } else { 221 priv->sreg_addr_max = priv->sreg_addr_min; 222 } 223 224 priv->flags |= NF_NAT_RANGE_MAP_IPS; 225 } 226 227 plen = sizeof_field(struct nf_nat_range, min_addr.all); 228 if (tb[NFTA_NAT_REG_PROTO_MIN]) { 229 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN], 230 &priv->sreg_proto_min, plen); 231 if (err < 0) 232 return err; 233 234 if (tb[NFTA_NAT_REG_PROTO_MAX]) { 235 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX], 236 &priv->sreg_proto_max, 237 plen); 238 if (err < 0) 239 return err; 240 } else { 241 priv->sreg_proto_max = priv->sreg_proto_min; 242 } 243 244 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED; 245 } 246 247 if (tb[NFTA_NAT_FLAGS]) { 248 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS])); 249 if (priv->flags & ~NF_NAT_RANGE_MASK) 250 return -EOPNOTSUPP; 251 } 252 253 return nf_ct_netns_get(ctx->net, family); 254 } 255 256 static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr) 257 { 258 const struct nft_nat *priv = nft_expr_priv(expr); 259 260 switch (priv->type) { 261 case NF_NAT_MANIP_SRC: 262 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT))) 263 goto nla_put_failure; 264 break; 265 case NF_NAT_MANIP_DST: 266 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) 267 goto nla_put_failure; 268 break; 269 } 270 271 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family))) 272 goto nla_put_failure; 273 274 if (priv->sreg_addr_min) { 275 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN, 276 priv->sreg_addr_min) || 277 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX, 278 priv->sreg_addr_max)) 279 goto nla_put_failure; 280 } 281 282 if (priv->sreg_proto_min) { 283 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN, 284 priv->sreg_proto_min) || 285 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX, 286 priv->sreg_proto_max)) 287 goto nla_put_failure; 288 } 289 290 if (priv->flags != 0) { 291 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags))) 292 goto nla_put_failure; 293 } 294 295 return 0; 296 297 nla_put_failure: 298 return -1; 299 } 300 301 static void 302 nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) 303 { 304 const struct nft_nat *priv = nft_expr_priv(expr); 305 306 nf_ct_netns_put(ctx->net, priv->family); 307 } 308 309 static struct nft_expr_type nft_nat_type; 310 static const struct nft_expr_ops nft_nat_ops = { 311 .type = &nft_nat_type, 312 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 313 .eval = nft_nat_eval, 314 .init = nft_nat_init, 315 .destroy = nft_nat_destroy, 316 .dump = nft_nat_dump, 317 .validate = nft_nat_validate, 318 }; 319 320 static struct nft_expr_type nft_nat_type __read_mostly = { 321 .name = "nat", 322 .ops = &nft_nat_ops, 323 .policy = nft_nat_policy, 324 .maxattr = NFTA_NAT_MAX, 325 .owner = THIS_MODULE, 326 }; 327 328 #ifdef CONFIG_NF_TABLES_INET 329 static void nft_nat_inet_eval(const struct nft_expr *expr, 330 struct nft_regs *regs, 331 const struct nft_pktinfo *pkt) 332 { 333 const struct nft_nat *priv = nft_expr_priv(expr); 334 335 if (priv->family == nft_pf(pkt)) 336 nft_nat_eval(expr, regs, pkt); 337 } 338 339 static const struct nft_expr_ops nft_nat_inet_ops = { 340 .type = &nft_nat_type, 341 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 342 .eval = nft_nat_inet_eval, 343 .init = nft_nat_init, 344 .destroy = nft_nat_destroy, 345 .dump = nft_nat_dump, 346 .validate = nft_nat_validate, 347 }; 348 349 static struct nft_expr_type nft_inet_nat_type __read_mostly = { 350 .name = "nat", 351 .family = NFPROTO_INET, 352 .ops = &nft_nat_inet_ops, 353 .policy = nft_nat_policy, 354 .maxattr = NFTA_NAT_MAX, 355 .owner = THIS_MODULE, 356 }; 357 358 static int nft_nat_inet_module_init(void) 359 { 360 return nft_register_expr(&nft_inet_nat_type); 361 } 362 363 static void nft_nat_inet_module_exit(void) 364 { 365 nft_unregister_expr(&nft_inet_nat_type); 366 } 367 #else 368 static int nft_nat_inet_module_init(void) { return 0; } 369 static void nft_nat_inet_module_exit(void) { } 370 #endif 371 372 static int __init nft_nat_module_init(void) 373 { 374 int ret = nft_nat_inet_module_init(); 375 376 if (ret) 377 return ret; 378 379 ret = nft_register_expr(&nft_nat_type); 380 if (ret) 381 nft_nat_inet_module_exit(); 382 383 return ret; 384 } 385 386 static void __exit nft_nat_module_exit(void) 387 { 388 nft_nat_inet_module_exit(); 389 nft_unregister_expr(&nft_nat_type); 390 } 391 392 module_init(nft_nat_module_init); 393 module_exit(nft_nat_module_exit); 394 395 MODULE_LICENSE("GPL"); 396 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>"); 397 MODULE_ALIAS_NFT_EXPR("nat"); 398 MODULE_DESCRIPTION("Network Address Translation support"); 399