Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 1 | /* |
Patrick McHardy | ef1f7df | 2013-10-10 11:41:20 +0200 | [diff] [blame] | 2 | * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 3 | * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org> |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * Development of this code funded by Astaro AG (http://www.astaro.com/) |
| 10 | */ |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/list.h> |
| 15 | #include <linux/skbuff.h> |
| 16 | #include <linux/ip.h> |
| 17 | #include <linux/netlink.h> |
| 18 | #include <linux/netfilter.h> |
| 19 | #include <linux/netfilter_ipv4.h> |
| 20 | #include <linux/netfilter/nfnetlink.h> |
| 21 | #include <linux/netfilter/nf_tables.h> |
| 22 | #include <net/netfilter/nf_conntrack.h> |
| 23 | #include <net/netfilter/nf_nat.h> |
| 24 | #include <net/netfilter/nf_nat_core.h> |
| 25 | #include <net/netfilter/nf_tables.h> |
| 26 | #include <net/netfilter/nf_nat_l3proto.h> |
| 27 | #include <net/ip.h> |
| 28 | |
| 29 | struct nft_nat { |
| 30 | enum nft_registers sreg_addr_min:8; |
| 31 | enum nft_registers sreg_addr_max:8; |
| 32 | enum nft_registers sreg_proto_min:8; |
| 33 | enum nft_registers sreg_proto_max:8; |
| 34 | enum nf_nat_manip_type type; |
| 35 | }; |
| 36 | |
| 37 | static void nft_nat_eval(const struct nft_expr *expr, |
| 38 | struct nft_data data[NFT_REG_MAX + 1], |
| 39 | const struct nft_pktinfo *pkt) |
| 40 | { |
| 41 | const struct nft_nat *priv = nft_expr_priv(expr); |
| 42 | enum ip_conntrack_info ctinfo; |
| 43 | struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo); |
| 44 | struct nf_nat_range range; |
| 45 | |
| 46 | memset(&range, 0, sizeof(range)); |
| 47 | if (priv->sreg_addr_min) { |
| 48 | range.min_addr.ip = data[priv->sreg_addr_min].data[0]; |
| 49 | range.max_addr.ip = data[priv->sreg_addr_max].data[0]; |
| 50 | range.flags |= NF_NAT_RANGE_MAP_IPS; |
| 51 | } |
| 52 | |
| 53 | if (priv->sreg_proto_min) { |
| 54 | range.min_proto.all = data[priv->sreg_proto_min].data[0]; |
| 55 | range.max_proto.all = data[priv->sreg_proto_max].data[0]; |
| 56 | range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED; |
| 57 | } |
| 58 | |
| 59 | data[NFT_REG_VERDICT].verdict = |
| 60 | nf_nat_setup_info(ct, &range, priv->type); |
| 61 | } |
| 62 | |
| 63 | static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = { |
| 64 | [NFTA_NAT_ADDR_MIN] = { .type = NLA_U32 }, |
| 65 | [NFTA_NAT_ADDR_MAX] = { .type = NLA_U32 }, |
| 66 | [NFTA_NAT_PROTO_MIN] = { .type = NLA_U32 }, |
| 67 | [NFTA_NAT_PROTO_MAX] = { .type = NLA_U32 }, |
| 68 | [NFTA_NAT_TYPE] = { .type = NLA_U32 }, |
| 69 | }; |
| 70 | |
| 71 | static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr, |
| 72 | const struct nlattr * const tb[]) |
| 73 | { |
| 74 | struct nft_nat *priv = nft_expr_priv(expr); |
| 75 | int err; |
| 76 | |
| 77 | if (tb[NFTA_NAT_TYPE] == NULL) |
| 78 | return -EINVAL; |
| 79 | |
| 80 | switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) { |
| 81 | case NFT_NAT_SNAT: |
| 82 | priv->type = NF_NAT_MANIP_SRC; |
| 83 | break; |
| 84 | case NFT_NAT_DNAT: |
| 85 | priv->type = NF_NAT_MANIP_DST; |
| 86 | break; |
| 87 | default: |
| 88 | return -EINVAL; |
| 89 | } |
| 90 | |
| 91 | if (tb[NFTA_NAT_ADDR_MIN]) { |
| 92 | priv->sreg_addr_min = ntohl(nla_get_be32(tb[NFTA_NAT_ADDR_MIN])); |
| 93 | err = nft_validate_input_register(priv->sreg_addr_min); |
| 94 | if (err < 0) |
| 95 | return err; |
| 96 | } |
| 97 | |
| 98 | if (tb[NFTA_NAT_ADDR_MAX]) { |
| 99 | priv->sreg_addr_max = ntohl(nla_get_be32(tb[NFTA_NAT_ADDR_MAX])); |
| 100 | err = nft_validate_input_register(priv->sreg_addr_max); |
| 101 | if (err < 0) |
| 102 | return err; |
| 103 | } else |
| 104 | priv->sreg_addr_max = priv->sreg_addr_min; |
| 105 | |
| 106 | if (tb[NFTA_NAT_PROTO_MIN]) { |
| 107 | priv->sreg_proto_min = ntohl(nla_get_be32(tb[NFTA_NAT_PROTO_MIN])); |
| 108 | err = nft_validate_input_register(priv->sreg_proto_min); |
| 109 | if (err < 0) |
| 110 | return err; |
| 111 | } |
| 112 | |
| 113 | if (tb[NFTA_NAT_PROTO_MAX]) { |
| 114 | priv->sreg_proto_max = ntohl(nla_get_be32(tb[NFTA_NAT_PROTO_MAX])); |
| 115 | err = nft_validate_input_register(priv->sreg_proto_max); |
| 116 | if (err < 0) |
| 117 | return err; |
| 118 | } else |
| 119 | priv->sreg_proto_max = priv->sreg_proto_min; |
| 120 | |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr) |
| 125 | { |
| 126 | const struct nft_nat *priv = nft_expr_priv(expr); |
| 127 | |
| 128 | switch (priv->type) { |
| 129 | case NF_NAT_MANIP_SRC: |
| 130 | if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT))) |
| 131 | goto nla_put_failure; |
| 132 | break; |
| 133 | case NF_NAT_MANIP_DST: |
| 134 | if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) |
| 135 | goto nla_put_failure; |
| 136 | break; |
| 137 | } |
| 138 | |
| 139 | if (nla_put_be32(skb, NFTA_NAT_ADDR_MIN, htonl(priv->sreg_addr_min))) |
| 140 | goto nla_put_failure; |
| 141 | if (nla_put_be32(skb, NFTA_NAT_ADDR_MAX, htonl(priv->sreg_addr_max))) |
| 142 | goto nla_put_failure; |
| 143 | if (nla_put_be32(skb, NFTA_NAT_PROTO_MIN, htonl(priv->sreg_proto_min))) |
| 144 | goto nla_put_failure; |
| 145 | if (nla_put_be32(skb, NFTA_NAT_PROTO_MAX, htonl(priv->sreg_proto_max))) |
| 146 | goto nla_put_failure; |
| 147 | return 0; |
| 148 | |
| 149 | nla_put_failure: |
| 150 | return -1; |
| 151 | } |
| 152 | |
Patrick McHardy | ef1f7df | 2013-10-10 11:41:20 +0200 | [diff] [blame] | 153 | static struct nft_expr_type nft_nat_type; |
| 154 | static const struct nft_expr_ops nft_nat_ops = { |
| 155 | .type = &nft_nat_type, |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 156 | .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 157 | .eval = nft_nat_eval, |
| 158 | .init = nft_nat_init, |
| 159 | .dump = nft_nat_dump, |
Patrick McHardy | ef1f7df | 2013-10-10 11:41:20 +0200 | [diff] [blame] | 160 | }; |
| 161 | |
| 162 | static struct nft_expr_type nft_nat_type __read_mostly = { |
| 163 | .name = "nat", |
| 164 | .ops = &nft_nat_ops, |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 165 | .policy = nft_nat_policy, |
| 166 | .maxattr = NFTA_NAT_MAX, |
Patrick McHardy | ef1f7df | 2013-10-10 11:41:20 +0200 | [diff] [blame] | 167 | .owner = THIS_MODULE, |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 168 | }; |
| 169 | |
| 170 | /* |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 171 | * NAT chains |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 172 | */ |
| 173 | |
| 174 | static unsigned int nf_nat_fn(const struct nf_hook_ops *ops, |
| 175 | struct sk_buff *skb, |
| 176 | const struct net_device *in, |
| 177 | const struct net_device *out, |
| 178 | int (*okfn)(struct sk_buff *)) |
| 179 | { |
| 180 | enum ip_conntrack_info ctinfo; |
| 181 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 182 | struct nf_conn_nat *nat; |
| 183 | enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum); |
| 184 | unsigned int ret; |
| 185 | |
| 186 | if (ct == NULL || nf_ct_is_untracked(ct)) |
| 187 | return NF_ACCEPT; |
| 188 | |
| 189 | NF_CT_ASSERT(!(ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET))); |
| 190 | |
| 191 | nat = nfct_nat(ct); |
| 192 | if (nat == NULL) { |
| 193 | /* Conntrack module was loaded late, can't add extension. */ |
| 194 | if (nf_ct_is_confirmed(ct)) |
| 195 | return NF_ACCEPT; |
| 196 | nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); |
| 197 | if (nat == NULL) |
| 198 | return NF_ACCEPT; |
| 199 | } |
| 200 | |
| 201 | switch (ctinfo) { |
| 202 | case IP_CT_RELATED: |
| 203 | case IP_CT_RELATED + IP_CT_IS_REPLY: |
| 204 | if (ip_hdr(skb)->protocol == IPPROTO_ICMP) { |
| 205 | if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo, |
| 206 | ops->hooknum)) |
| 207 | return NF_DROP; |
| 208 | else |
| 209 | return NF_ACCEPT; |
| 210 | } |
| 211 | /* Fall through */ |
| 212 | case IP_CT_NEW: |
| 213 | if (nf_nat_initialized(ct, maniptype)) |
| 214 | break; |
| 215 | |
| 216 | ret = nft_do_chain(ops, skb, in, out, okfn); |
| 217 | if (ret != NF_ACCEPT) |
| 218 | return ret; |
| 219 | if (!nf_nat_initialized(ct, maniptype)) { |
| 220 | ret = nf_nat_alloc_null_binding(ct, ops->hooknum); |
| 221 | if (ret != NF_ACCEPT) |
| 222 | return ret; |
| 223 | } |
| 224 | default: |
| 225 | break; |
| 226 | } |
| 227 | |
| 228 | return nf_nat_packet(ct, ctinfo, ops->hooknum, skb); |
| 229 | } |
| 230 | |
| 231 | static unsigned int nf_nat_prerouting(const struct nf_hook_ops *ops, |
| 232 | struct sk_buff *skb, |
| 233 | const struct net_device *in, |
| 234 | const struct net_device *out, |
| 235 | int (*okfn)(struct sk_buff *)) |
| 236 | { |
| 237 | __be32 daddr = ip_hdr(skb)->daddr; |
| 238 | unsigned int ret; |
| 239 | |
| 240 | ret = nf_nat_fn(ops, skb, in, out, okfn); |
| 241 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 242 | ip_hdr(skb)->daddr != daddr) { |
| 243 | skb_dst_drop(skb); |
| 244 | } |
| 245 | return ret; |
| 246 | } |
| 247 | |
| 248 | static unsigned int nf_nat_postrouting(const struct nf_hook_ops *ops, |
| 249 | struct sk_buff *skb, |
| 250 | const struct net_device *in, |
| 251 | const struct net_device *out, |
| 252 | int (*okfn)(struct sk_buff *)) |
| 253 | { |
| 254 | enum ip_conntrack_info ctinfo __maybe_unused; |
| 255 | const struct nf_conn *ct __maybe_unused; |
| 256 | unsigned int ret; |
| 257 | |
| 258 | ret = nf_nat_fn(ops, skb, in, out, okfn); |
| 259 | #ifdef CONFIG_XFRM |
| 260 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 261 | (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| 262 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| 263 | |
| 264 | if (ct->tuplehash[dir].tuple.src.u3.ip != |
| 265 | ct->tuplehash[!dir].tuple.dst.u3.ip || |
| 266 | ct->tuplehash[dir].tuple.src.u.all != |
| 267 | ct->tuplehash[!dir].tuple.dst.u.all) |
| 268 | return nf_xfrm_me_harder(skb, AF_INET) == 0 ? |
| 269 | ret : NF_DROP; |
| 270 | } |
| 271 | #endif |
| 272 | return ret; |
| 273 | } |
| 274 | |
| 275 | static unsigned int nf_nat_output(const struct nf_hook_ops *ops, |
| 276 | struct sk_buff *skb, |
| 277 | const struct net_device *in, |
| 278 | const struct net_device *out, |
| 279 | int (*okfn)(struct sk_buff *)) |
| 280 | { |
| 281 | enum ip_conntrack_info ctinfo; |
| 282 | const struct nf_conn *ct; |
| 283 | unsigned int ret; |
| 284 | |
| 285 | ret = nf_nat_fn(ops, skb, in, out, okfn); |
| 286 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 287 | (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| 288 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| 289 | |
| 290 | if (ct->tuplehash[dir].tuple.dst.u3.ip != |
| 291 | ct->tuplehash[!dir].tuple.src.u3.ip) { |
| 292 | if (ip_route_me_harder(skb, RTN_UNSPEC)) |
| 293 | ret = NF_DROP; |
| 294 | } |
| 295 | #ifdef CONFIG_XFRM |
| 296 | else if (ct->tuplehash[dir].tuple.dst.u.all != |
| 297 | ct->tuplehash[!dir].tuple.src.u.all) |
| 298 | if (nf_xfrm_me_harder(skb, AF_INET)) |
| 299 | ret = NF_DROP; |
| 300 | #endif |
| 301 | } |
| 302 | return ret; |
| 303 | } |
| 304 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 305 | struct nf_chain_type nft_chain_nat_ipv4 = { |
| 306 | .family = NFPROTO_IPV4, |
| 307 | .name = "nat", |
| 308 | .type = NFT_CHAIN_T_NAT, |
| 309 | .hook_mask = (1 << NF_INET_PRE_ROUTING) | |
| 310 | (1 << NF_INET_POST_ROUTING) | |
| 311 | (1 << NF_INET_LOCAL_OUT) | |
| 312 | (1 << NF_INET_LOCAL_IN), |
| 313 | .fn = { |
| 314 | [NF_INET_PRE_ROUTING] = nf_nat_prerouting, |
| 315 | [NF_INET_POST_ROUTING] = nf_nat_postrouting, |
| 316 | [NF_INET_LOCAL_OUT] = nf_nat_output, |
| 317 | [NF_INET_LOCAL_IN] = nf_nat_fn, |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 318 | }, |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 319 | .me = THIS_MODULE, |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 320 | }; |
| 321 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 322 | static int __init nft_chain_nat_init(void) |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 323 | { |
| 324 | int err; |
| 325 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 326 | err = nft_register_chain_type(&nft_chain_nat_ipv4); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 327 | if (err < 0) |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 328 | return err; |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 329 | |
Patrick McHardy | ef1f7df | 2013-10-10 11:41:20 +0200 | [diff] [blame] | 330 | err = nft_register_expr(&nft_nat_type); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 331 | if (err < 0) |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 332 | goto err; |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 333 | |
| 334 | return 0; |
| 335 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 336 | err: |
| 337 | nft_unregister_chain_type(&nft_chain_nat_ipv4); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 338 | return err; |
| 339 | } |
| 340 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 341 | static void __exit nft_chain_nat_exit(void) |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 342 | { |
Patrick McHardy | ef1f7df | 2013-10-10 11:41:20 +0200 | [diff] [blame] | 343 | nft_unregister_expr(&nft_nat_type); |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 344 | nft_unregister_chain_type(&nft_chain_nat_ipv4); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 345 | } |
| 346 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 347 | module_init(nft_chain_nat_init); |
| 348 | module_exit(nft_chain_nat_exit); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 349 | |
| 350 | MODULE_LICENSE("GPL"); |
| 351 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame^] | 352 | MODULE_ALIAS_NFT_CHAIN(AF_INET, "nat"); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 353 | MODULE_ALIAS_NFT_EXPR("nat"); |