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 23struct 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 33static 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 53static 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 63static 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 103static 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 128static 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 139static 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 if (ctx->family != NFPROTO_IPV4 && 147 ctx->family != NFPROTO_IPV6 && 148 ctx->family != NFPROTO_INET) 149 return -EOPNOTSUPP; 150 151 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT); 152 if (err < 0) 153 return err; 154 155 switch (priv->type) { 156 case NFT_NAT_SNAT: 157 err = nft_chain_validate_hooks(ctx->chain, 158 (1 << NF_INET_POST_ROUTING) | 159 (1 << NF_INET_LOCAL_IN)); 160 break; 161 case NFT_NAT_DNAT: 162 err = nft_chain_validate_hooks(ctx->chain, 163 (1 << NF_INET_PRE_ROUTING) | 164 (1 << NF_INET_LOCAL_OUT)); 165 break; 166 } 167 168 return err; 169} 170 171static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 172 const struct nlattr * const tb[]) 173{ 174 struct nft_nat *priv = nft_expr_priv(expr); 175 unsigned int alen, plen; 176 u32 family; 177 int err; 178 179 if (tb[NFTA_NAT_TYPE] == NULL || 180 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL && 181 tb[NFTA_NAT_REG_PROTO_MIN] == NULL)) 182 return -EINVAL; 183 184 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) { 185 case NFT_NAT_SNAT: 186 priv->type = NF_NAT_MANIP_SRC; 187 break; 188 case NFT_NAT_DNAT: 189 priv->type = NF_NAT_MANIP_DST; 190 break; 191 default: 192 return -EOPNOTSUPP; 193 } 194 195 if (tb[NFTA_NAT_FAMILY] == NULL) 196 return -EINVAL; 197 198 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY])); 199 if (ctx->family != NFPROTO_INET && ctx->family != family) 200 return -EOPNOTSUPP; 201 202 switch (family) { 203 case NFPROTO_IPV4: 204 alen = sizeof_field(struct nf_nat_range, min_addr.ip); 205 break; 206 case NFPROTO_IPV6: 207 alen = sizeof_field(struct nf_nat_range, min_addr.ip6); 208 break; 209 default: 210 if (tb[NFTA_NAT_REG_ADDR_MIN]) 211 return -EAFNOSUPPORT; 212 break; 213 } 214 priv->family = family; 215 216 if (tb[NFTA_NAT_REG_ADDR_MIN]) { 217 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN], 218 &priv->sreg_addr_min, alen); 219 if (err < 0) 220 return err; 221 222 if (tb[NFTA_NAT_REG_ADDR_MAX]) { 223 err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX], 224 &priv->sreg_addr_max, 225 alen); 226 if (err < 0) 227 return err; 228 } else { 229 priv->sreg_addr_max = priv->sreg_addr_min; 230 } 231 232 priv->flags |= NF_NAT_RANGE_MAP_IPS; 233 } 234 235 plen = sizeof_field(struct nf_nat_range, min_proto.all); 236 if (tb[NFTA_NAT_REG_PROTO_MIN]) { 237 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN], 238 &priv->sreg_proto_min, plen); 239 if (err < 0) 240 return err; 241 242 if (tb[NFTA_NAT_REG_PROTO_MAX]) { 243 err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX], 244 &priv->sreg_proto_max, 245 plen); 246 if (err < 0) 247 return err; 248 } else { 249 priv->sreg_proto_max = priv->sreg_proto_min; 250 } 251 252 priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED; 253 } 254 255 if (tb[NFTA_NAT_FLAGS]) 256 priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS])); 257 258 return nf_ct_netns_get(ctx->net, family); 259} 260 261static int nft_nat_dump(struct sk_buff *skb, 262 const struct nft_expr *expr, bool reset) 263{ 264 const struct nft_nat *priv = nft_expr_priv(expr); 265 266 switch (priv->type) { 267 case NF_NAT_MANIP_SRC: 268 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT))) 269 goto nla_put_failure; 270 break; 271 case NF_NAT_MANIP_DST: 272 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) 273 goto nla_put_failure; 274 break; 275 } 276 277 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family))) 278 goto nla_put_failure; 279 280 if (priv->sreg_addr_min) { 281 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN, 282 priv->sreg_addr_min) || 283 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX, 284 priv->sreg_addr_max)) 285 goto nla_put_failure; 286 } 287 288 if (priv->sreg_proto_min) { 289 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN, 290 priv->sreg_proto_min) || 291 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX, 292 priv->sreg_proto_max)) 293 goto nla_put_failure; 294 } 295 296 if (priv->flags != 0) { 297 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags))) 298 goto nla_put_failure; 299 } 300 301 return 0; 302 303nla_put_failure: 304 return -1; 305} 306 307static void 308nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) 309{ 310 const struct nft_nat *priv = nft_expr_priv(expr); 311 312 nf_ct_netns_put(ctx->net, priv->family); 313} 314 315static struct nft_expr_type nft_nat_type; 316static const struct nft_expr_ops nft_nat_ops = { 317 .type = &nft_nat_type, 318 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 319 .eval = nft_nat_eval, 320 .init = nft_nat_init, 321 .destroy = nft_nat_destroy, 322 .dump = nft_nat_dump, 323 .validate = nft_nat_validate, 324 .reduce = NFT_REDUCE_READONLY, 325}; 326 327static struct nft_expr_type nft_nat_type __read_mostly = { 328 .name = "nat", 329 .ops = &nft_nat_ops, 330 .policy = nft_nat_policy, 331 .maxattr = NFTA_NAT_MAX, 332 .owner = THIS_MODULE, 333}; 334 335#ifdef CONFIG_NF_TABLES_INET 336static void nft_nat_inet_eval(const struct nft_expr *expr, 337 struct nft_regs *regs, 338 const struct nft_pktinfo *pkt) 339{ 340 const struct nft_nat *priv = nft_expr_priv(expr); 341 342 if (priv->family == nft_pf(pkt) || 343 priv->family == NFPROTO_INET) 344 nft_nat_eval(expr, regs, pkt); 345} 346 347static const struct nft_expr_ops nft_nat_inet_ops = { 348 .type = &nft_nat_type, 349 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 350 .eval = nft_nat_inet_eval, 351 .init = nft_nat_init, 352 .destroy = nft_nat_destroy, 353 .dump = nft_nat_dump, 354 .validate = nft_nat_validate, 355 .reduce = NFT_REDUCE_READONLY, 356}; 357 358static struct nft_expr_type nft_inet_nat_type __read_mostly = { 359 .name = "nat", 360 .family = NFPROTO_INET, 361 .ops = &nft_nat_inet_ops, 362 .policy = nft_nat_policy, 363 .maxattr = NFTA_NAT_MAX, 364 .owner = THIS_MODULE, 365}; 366 367static int nft_nat_inet_module_init(void) 368{ 369 return nft_register_expr(&nft_inet_nat_type); 370} 371 372static void nft_nat_inet_module_exit(void) 373{ 374 nft_unregister_expr(&nft_inet_nat_type); 375} 376#else 377static int nft_nat_inet_module_init(void) { return 0; } 378static void nft_nat_inet_module_exit(void) { } 379#endif 380 381static int __init nft_nat_module_init(void) 382{ 383 int ret = nft_nat_inet_module_init(); 384 385 if (ret) 386 return ret; 387 388 ret = nft_register_expr(&nft_nat_type); 389 if (ret) 390 nft_nat_inet_module_exit(); 391 392 return ret; 393} 394 395static void __exit nft_nat_module_exit(void) 396{ 397 nft_nat_inet_module_exit(); 398 nft_unregister_expr(&nft_nat_type); 399} 400 401module_init(nft_nat_module_init); 402module_exit(nft_nat_module_exit); 403 404MODULE_LICENSE("GPL"); 405MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>"); 406MODULE_ALIAS_NFT_EXPR("nat"); 407MODULE_DESCRIPTION("Network Address Translation support"); 408