1 /* 2 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 3 * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org> 4 * Copyright (c) 2012 Intel Corporation 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 */ 11 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/skbuff.h> 15 #include <linux/ip.h> 16 #include <linux/string.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:8; 35 u8 family; 36 u16 flags; 37 }; 38 39 static void nft_nat_eval(const struct nft_expr *expr, 40 struct nft_regs *regs, 41 const struct nft_pktinfo *pkt) 42 { 43 const struct nft_nat *priv = nft_expr_priv(expr); 44 enum ip_conntrack_info ctinfo; 45 struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo); 46 struct nf_nat_range2 range; 47 48 memset(&range, 0, sizeof(range)); 49 if (priv->sreg_addr_min) { 50 if (priv->family == AF_INET) { 51 range.min_addr.ip = (__force __be32) 52 regs->data[priv->sreg_addr_min]; 53 range.max_addr.ip = (__force __be32) 54 regs->data[priv->sreg_addr_max]; 55 56 } else { 57 memcpy(range.min_addr.ip6, 58 ®s->data[priv->sreg_addr_min], 59 sizeof(range.min_addr.ip6)); 60 memcpy(range.max_addr.ip6, 61 ®s->data[priv->sreg_addr_max], 62 sizeof(range.max_addr.ip6)); 63 } 64 range.flags |= NF_NAT_RANGE_MAP_IPS; 65 } 66 67 if (priv->sreg_proto_min) { 68 range.min_proto.all = (__force __be16)nft_reg_load16( 69 ®s->data[priv->sreg_proto_min]); 70 range.max_proto.all = (__force __be16)nft_reg_load16( 71 ®s->data[priv->sreg_proto_max]); 72 range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED; 73 } 74 75 range.flags |= priv->flags; 76 77 regs->verdict.code = nf_nat_setup_info(ct, &range, priv->type); 78 } 79 80 static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = { 81 [NFTA_NAT_TYPE] = { .type = NLA_U32 }, 82 [NFTA_NAT_FAMILY] = { .type = NLA_U32 }, 83 [NFTA_NAT_REG_ADDR_MIN] = { .type = NLA_U32 }, 84 [NFTA_NAT_REG_ADDR_MAX] = { .type = NLA_U32 }, 85 [NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 }, 86 [NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 }, 87 [NFTA_NAT_FLAGS] = { .type = NLA_U32 }, 88 }; 89 90 static int nft_nat_validate(const struct nft_ctx *ctx, 91 const struct nft_expr *expr, 92 const struct nft_data **data) 93 { 94 struct nft_nat *priv = nft_expr_priv(expr); 95 int err; 96 97 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT); 98 if (err < 0) 99 return err; 100 101 switch (priv->type) { 102 case NFT_NAT_SNAT: 103 err = nft_chain_validate_hooks(ctx->chain, 104 (1 << NF_INET_POST_ROUTING) | 105 (1 << NF_INET_LOCAL_IN)); 106 break; 107 case NFT_NAT_DNAT: 108 err = nft_chain_validate_hooks(ctx->chain, 109 (1 << NF_INET_PRE_ROUTING) | 110 (1 << NF_INET_LOCAL_OUT)); 111 break; 112 } 113 114 return err; 115 } 116 117 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 118 const struct nlattr * const tb[]) 119 { 120 struct nft_nat *priv = nft_expr_priv(expr); 121 unsigned int alen, plen; 122 u32 family; 123 int err; 124 125 if (tb[NFTA_NAT_TYPE] == NULL || 126 (tb[NFTA_NAT_REG_ADDR_MIN] == NULL && 127 tb[NFTA_NAT_REG_PROTO_MIN] == NULL)) 128 return -EINVAL; 129 130 switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) { 131 case NFT_NAT_SNAT: 132 priv->type = NF_NAT_MANIP_SRC; 133 break; 134 case NFT_NAT_DNAT: 135 priv->type = NF_NAT_MANIP_DST; 136 break; 137 default: 138 return -EINVAL; 139 } 140 141 if (tb[NFTA_NAT_FAMILY] == NULL) 142 return -EINVAL; 143 144 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY])); 145 if (family != ctx->family) 146 return -EOPNOTSUPP; 147 148 switch (family) { 149 case NFPROTO_IPV4: 150 alen = FIELD_SIZEOF(struct nf_nat_range, min_addr.ip); 151 break; 152 case NFPROTO_IPV6: 153 alen = FIELD_SIZEOF(struct nf_nat_range, min_addr.ip6); 154 break; 155 default: 156 return -EAFNOSUPPORT; 157 } 158 priv->family = family; 159 160 if (tb[NFTA_NAT_REG_ADDR_MIN]) { 161 priv->sreg_addr_min = 162 nft_parse_register(tb[NFTA_NAT_REG_ADDR_MIN]); 163 err = nft_validate_register_load(priv->sreg_addr_min, alen); 164 if (err < 0) 165 return err; 166 167 if (tb[NFTA_NAT_REG_ADDR_MAX]) { 168 priv->sreg_addr_max = 169 nft_parse_register(tb[NFTA_NAT_REG_ADDR_MAX]); 170 171 err = nft_validate_register_load(priv->sreg_addr_max, 172 alen); 173 if (err < 0) 174 return err; 175 } else { 176 priv->sreg_addr_max = priv->sreg_addr_min; 177 } 178 } 179 180 plen = FIELD_SIZEOF(struct nf_nat_range, min_addr.all); 181 if (tb[NFTA_NAT_REG_PROTO_MIN]) { 182 priv->sreg_proto_min = 183 nft_parse_register(tb[NFTA_NAT_REG_PROTO_MIN]); 184 185 err = nft_validate_register_load(priv->sreg_proto_min, plen); 186 if (err < 0) 187 return err; 188 189 if (tb[NFTA_NAT_REG_PROTO_MAX]) { 190 priv->sreg_proto_max = 191 nft_parse_register(tb[NFTA_NAT_REG_PROTO_MAX]); 192 193 err = nft_validate_register_load(priv->sreg_proto_max, 194 plen); 195 if (err < 0) 196 return err; 197 } else { 198 priv->sreg_proto_max = priv->sreg_proto_min; 199 } 200 } 201 202 if (tb[NFTA_NAT_FLAGS]) { 203 priv->flags = ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS])); 204 if (priv->flags & ~NF_NAT_RANGE_MASK) 205 return -EINVAL; 206 } 207 208 return nf_ct_netns_get(ctx->net, family); 209 } 210 211 static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr) 212 { 213 const struct nft_nat *priv = nft_expr_priv(expr); 214 215 switch (priv->type) { 216 case NF_NAT_MANIP_SRC: 217 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT))) 218 goto nla_put_failure; 219 break; 220 case NF_NAT_MANIP_DST: 221 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) 222 goto nla_put_failure; 223 break; 224 } 225 226 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family))) 227 goto nla_put_failure; 228 229 if (priv->sreg_addr_min) { 230 if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN, 231 priv->sreg_addr_min) || 232 nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX, 233 priv->sreg_addr_max)) 234 goto nla_put_failure; 235 } 236 237 if (priv->sreg_proto_min) { 238 if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN, 239 priv->sreg_proto_min) || 240 nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX, 241 priv->sreg_proto_max)) 242 goto nla_put_failure; 243 } 244 245 if (priv->flags != 0) { 246 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags))) 247 goto nla_put_failure; 248 } 249 250 return 0; 251 252 nla_put_failure: 253 return -1; 254 } 255 256 static void 257 nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) 258 { 259 const struct nft_nat *priv = nft_expr_priv(expr); 260 261 nf_ct_netns_put(ctx->net, priv->family); 262 } 263 264 static struct nft_expr_type nft_nat_type; 265 static const struct nft_expr_ops nft_nat_ops = { 266 .type = &nft_nat_type, 267 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 268 .eval = nft_nat_eval, 269 .init = nft_nat_init, 270 .destroy = nft_nat_destroy, 271 .dump = nft_nat_dump, 272 .validate = nft_nat_validate, 273 }; 274 275 static struct nft_expr_type nft_nat_type __read_mostly = { 276 .name = "nat", 277 .ops = &nft_nat_ops, 278 .policy = nft_nat_policy, 279 .maxattr = NFTA_NAT_MAX, 280 .owner = THIS_MODULE, 281 }; 282 283 static int __init nft_nat_module_init(void) 284 { 285 return nft_register_expr(&nft_nat_type); 286 } 287 288 static void __exit nft_nat_module_exit(void) 289 { 290 nft_unregister_expr(&nft_nat_type); 291 } 292 293 module_init(nft_nat_module_init); 294 module_exit(nft_nat_module_exit); 295 296 MODULE_LICENSE("GPL"); 297 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>"); 298 MODULE_ALIAS_NFT_EXPR("nat"); 299