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_data data[NFT_REG_MAX + 1], 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_range 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 data[priv->sreg_addr_min].data[0]; 53 range.max_addr.ip = (__force __be32) 54 data[priv->sreg_addr_max].data[0]; 55 56 } else { 57 memcpy(range.min_addr.ip6, 58 data[priv->sreg_addr_min].data, 59 sizeof(struct nft_data)); 60 memcpy(range.max_addr.ip6, 61 data[priv->sreg_addr_max].data, 62 sizeof(struct nft_data)); 63 } 64 range.flags |= NF_NAT_RANGE_MAP_IPS; 65 } 66 67 if (priv->sreg_proto_min) { 68 range.min_proto.all = 69 *(__be16 *)&data[priv->sreg_proto_min].data[0]; 70 range.max_proto.all = 71 *(__be16 *)&data[priv->sreg_proto_max].data[0]; 72 range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED; 73 } 74 75 range.flags |= priv->flags; 76 77 data[NFT_REG_VERDICT].verdict = 78 nf_nat_setup_info(ct, &range, priv->type); 79 } 80 81 static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = { 82 [NFTA_NAT_TYPE] = { .type = NLA_U32 }, 83 [NFTA_NAT_FAMILY] = { .type = NLA_U32 }, 84 [NFTA_NAT_REG_ADDR_MIN] = { .type = NLA_U32 }, 85 [NFTA_NAT_REG_ADDR_MAX] = { .type = NLA_U32 }, 86 [NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 }, 87 [NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 }, 88 [NFTA_NAT_FLAGS] = { .type = NLA_U32 }, 89 }; 90 91 static int nft_nat_validate(const struct nft_ctx *ctx, 92 const struct nft_expr *expr, 93 const struct nft_data **data) 94 { 95 struct nft_nat *priv = nft_expr_priv(expr); 96 int err; 97 98 err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT); 99 if (err < 0) 100 return err; 101 102 switch (priv->type) { 103 case NFT_NAT_SNAT: 104 err = nft_chain_validate_hooks(ctx->chain, 105 (1 << NF_INET_POST_ROUTING) | 106 (1 << NF_INET_LOCAL_IN)); 107 break; 108 case NFT_NAT_DNAT: 109 err = nft_chain_validate_hooks(ctx->chain, 110 (1 << NF_INET_PRE_ROUTING) | 111 (1 << NF_INET_LOCAL_OUT)); 112 break; 113 } 114 115 return err; 116 } 117 118 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 119 const struct nlattr * const tb[]) 120 { 121 struct nft_nat *priv = nft_expr_priv(expr); 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 err = nft_nat_validate(ctx, expr, NULL); 142 if (err < 0) 143 return err; 144 145 if (tb[NFTA_NAT_FAMILY] == NULL) 146 return -EINVAL; 147 148 family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY])); 149 if (family != AF_INET && family != AF_INET6) 150 return -EAFNOSUPPORT; 151 if (family != ctx->afi->family) 152 return -EOPNOTSUPP; 153 priv->family = family; 154 155 if (tb[NFTA_NAT_REG_ADDR_MIN]) { 156 priv->sreg_addr_min = 157 ntohl(nla_get_be32(tb[NFTA_NAT_REG_ADDR_MIN])); 158 159 err = nft_validate_input_register(priv->sreg_addr_min); 160 if (err < 0) 161 return err; 162 163 if (tb[NFTA_NAT_REG_ADDR_MAX]) { 164 priv->sreg_addr_max = 165 ntohl(nla_get_be32(tb[NFTA_NAT_REG_ADDR_MAX])); 166 167 err = nft_validate_input_register(priv->sreg_addr_max); 168 if (err < 0) 169 return err; 170 } else { 171 priv->sreg_addr_max = priv->sreg_addr_min; 172 } 173 } 174 175 if (tb[NFTA_NAT_REG_PROTO_MIN]) { 176 priv->sreg_proto_min = 177 ntohl(nla_get_be32(tb[NFTA_NAT_REG_PROTO_MIN])); 178 179 err = nft_validate_input_register(priv->sreg_proto_min); 180 if (err < 0) 181 return err; 182 183 if (tb[NFTA_NAT_REG_PROTO_MAX]) { 184 priv->sreg_proto_max = 185 ntohl(nla_get_be32(tb[NFTA_NAT_REG_PROTO_MAX])); 186 187 err = nft_validate_input_register(priv->sreg_proto_max); 188 if (err < 0) 189 return err; 190 } else { 191 priv->sreg_proto_max = priv->sreg_proto_min; 192 } 193 } 194 195 if (tb[NFTA_NAT_FLAGS]) { 196 priv->flags = ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS])); 197 if (priv->flags & ~NF_NAT_RANGE_MASK) 198 return -EINVAL; 199 } 200 201 return 0; 202 } 203 204 static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr) 205 { 206 const struct nft_nat *priv = nft_expr_priv(expr); 207 208 switch (priv->type) { 209 case NF_NAT_MANIP_SRC: 210 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT))) 211 goto nla_put_failure; 212 break; 213 case NF_NAT_MANIP_DST: 214 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT))) 215 goto nla_put_failure; 216 break; 217 } 218 219 if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family))) 220 goto nla_put_failure; 221 222 if (priv->sreg_addr_min) { 223 if (nla_put_be32(skb, NFTA_NAT_REG_ADDR_MIN, 224 htonl(priv->sreg_addr_min)) || 225 nla_put_be32(skb, NFTA_NAT_REG_ADDR_MAX, 226 htonl(priv->sreg_addr_max))) 227 goto nla_put_failure; 228 } 229 230 if (priv->sreg_proto_min) { 231 if (nla_put_be32(skb, NFTA_NAT_REG_PROTO_MIN, 232 htonl(priv->sreg_proto_min)) || 233 nla_put_be32(skb, NFTA_NAT_REG_PROTO_MAX, 234 htonl(priv->sreg_proto_max))) 235 goto nla_put_failure; 236 } 237 238 if (priv->flags != 0) { 239 if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags))) 240 goto nla_put_failure; 241 } 242 243 return 0; 244 245 nla_put_failure: 246 return -1; 247 } 248 249 static struct nft_expr_type nft_nat_type; 250 static const struct nft_expr_ops nft_nat_ops = { 251 .type = &nft_nat_type, 252 .size = NFT_EXPR_SIZE(sizeof(struct nft_nat)), 253 .eval = nft_nat_eval, 254 .init = nft_nat_init, 255 .dump = nft_nat_dump, 256 .validate = nft_nat_validate, 257 }; 258 259 static struct nft_expr_type nft_nat_type __read_mostly = { 260 .name = "nat", 261 .ops = &nft_nat_ops, 262 .policy = nft_nat_policy, 263 .maxattr = NFTA_NAT_MAX, 264 .owner = THIS_MODULE, 265 }; 266 267 static int __init nft_nat_module_init(void) 268 { 269 return nft_register_expr(&nft_nat_type); 270 } 271 272 static void __exit nft_nat_module_exit(void) 273 { 274 nft_unregister_expr(&nft_nat_type); 275 } 276 277 module_init(nft_nat_module_init); 278 module_exit(nft_nat_module_exit); 279 280 MODULE_LICENSE("GPL"); 281 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>"); 282 MODULE_ALIAS_NFT_EXPR("nat"); 283