net/netfilter/nft_nat.c

   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 };
  37
  38 static void nft_nat_eval(const struct nft_expr *expr,
  39                          struct nft_data data[NFT_REG_MAX + 1],
  40                          const struct nft_pktinfo *pkt)
  41 {
  42         const struct nft_nat *priv = nft_expr_priv(expr);
  43         enum ip_conntrack_info ctinfo;
  44         struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo);
  45         struct nf_nat_range range;
  46
  47         memset(&range, 0, sizeof(range));
  48         if (priv->sreg_addr_min) {
  49                 if (priv->family == AF_INET) {
  50                         range.min_addr.ip = (__force __be32)
  51                                         data[priv->sreg_addr_min].data[0];
  52                         range.max_addr.ip = (__force __be32)
  53                                         data[priv->sreg_addr_max].data[0];
  54
  55                 } else {
  56                         memcpy(range.min_addr.ip6,
  57                                data[priv->sreg_addr_min].data,
  58                                sizeof(struct nft_data));
  59                         memcpy(range.max_addr.ip6,
  60                                data[priv->sreg_addr_max].data,
  61                                sizeof(struct nft_data));
  62                 }
  63                 range.flags |= NF_NAT_RANGE_MAP_IPS;
  64         }
  65
  66         if (priv->sreg_proto_min) {
  67                 range.min_proto.all = (__force __be16)
  68                                         data[priv->sreg_proto_min].data[0];
  69                 range.max_proto.all = (__force __be16)
  70                                         data[priv->sreg_proto_max].data[0];
  71                 range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
  72         }
  73
  74         data[NFT_REG_VERDICT].verdict =
  75                 nf_nat_setup_info(ct, &range, priv->type);
  76 }
  77
  78 static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = {
  79         [NFTA_NAT_TYPE]          = { .type = NLA_U32 },
  80         [NFTA_NAT_FAMILY]        = { .type = NLA_U32 },
  81         [NFTA_NAT_REG_ADDR_MIN]  = { .type = NLA_U32 },
  82         [NFTA_NAT_REG_ADDR_MAX]  = { .type = NLA_U32 },
  83         [NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 },
  84         [NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 },
  85 };
  86
  87 static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
  88                         const struct nlattr * const tb[])
  89 {
  90         struct nft_nat *priv = nft_expr_priv(expr);
  91         u32 family;
  92         int err;
  93
  94         if (tb[NFTA_NAT_TYPE] == NULL)
  95                 return -EINVAL;
  96
  97         switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
  98         case NFT_NAT_SNAT:
  99                 priv->type = NF_NAT_MANIP_SRC;
 100                 break;
 101         case NFT_NAT_DNAT:
 102                 priv->type = NF_NAT_MANIP_DST;
 103                 break;
 104         default:
 105                 return -EINVAL;
 106         }
 107
 108         if (tb[NFTA_NAT_FAMILY] == NULL)
 109                 return -EINVAL;
 110
 111         family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
 112         if (family != AF_INET && family != AF_INET6)
 113                 return -EAFNOSUPPORT;
 114         if (family != ctx->afi->family)
 115                 return -EOPNOTSUPP;
 116         priv->family = family;
 117
 118         if (tb[NFTA_NAT_REG_ADDR_MIN]) {
 119                 priv->sreg_addr_min = ntohl(nla_get_be32(
 120                                                 tb[NFTA_NAT_REG_ADDR_MIN]));
 121                 err = nft_validate_input_register(priv->sreg_addr_min);
 122                 if (err < 0)
 123                         return err;
 124         }
 125
 126         if (tb[NFTA_NAT_REG_ADDR_MAX]) {
 127                 priv->sreg_addr_max = ntohl(nla_get_be32(
 128                                                 tb[NFTA_NAT_REG_ADDR_MAX]));
 129                 err = nft_validate_input_register(priv->sreg_addr_max);
 130                 if (err < 0)
 131                         return err;
 132         } else
 133                 priv->sreg_addr_max = priv->sreg_addr_min;
 134
 135         if (tb[NFTA_NAT_REG_PROTO_MIN]) {
 136                 priv->sreg_proto_min = ntohl(nla_get_be32(
 137                                                 tb[NFTA_NAT_REG_PROTO_MIN]));
 138                 err = nft_validate_input_register(priv->sreg_proto_min);
 139                 if (err < 0)
 140                         return err;
 141         }
 142
 143         if (tb[NFTA_NAT_REG_PROTO_MAX]) {
 144                 priv->sreg_proto_max = ntohl(nla_get_be32(
 145                                                 tb[NFTA_NAT_REG_PROTO_MAX]));
 146                 err = nft_validate_input_register(priv->sreg_proto_max);
 147                 if (err < 0)
 148                         return err;
 149         } else
 150                 priv->sreg_proto_max = priv->sreg_proto_min;
 151
 152         return 0;
 153 }
 154
 155 static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
 156 {
 157         const struct nft_nat *priv = nft_expr_priv(expr);
 158
 159         switch (priv->type) {
 160         case NF_NAT_MANIP_SRC:
 161                 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
 162                         goto nla_put_failure;
 163                 break;
 164         case NF_NAT_MANIP_DST:
 165                 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
 166                         goto nla_put_failure;
 167                 break;
 168         }
 169
 170         if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
 171                 goto nla_put_failure;
 172         if (nla_put_be32(skb,
 173                          NFTA_NAT_REG_ADDR_MIN, htonl(priv->sreg_addr_min)))
 174                 goto nla_put_failure;
 175         if (nla_put_be32(skb,
 176                          NFTA_NAT_REG_ADDR_MAX, htonl(priv->sreg_addr_max)))
 177                 goto nla_put_failure;
 178         if (nla_put_be32(skb,
 179                          NFTA_NAT_REG_PROTO_MIN, htonl(priv->sreg_proto_min)))
 180                 goto nla_put_failure;
 181         if (nla_put_be32(skb,
 182                          NFTA_NAT_REG_PROTO_MAX, htonl(priv->sreg_proto_max)))
 183                 goto nla_put_failure;
 184         return 0;
 185
 186 nla_put_failure:
 187         return -1;
 188 }
 189
 190 static struct nft_expr_type nft_nat_type;
 191 static const struct nft_expr_ops nft_nat_ops = {
 192         .type           = &nft_nat_type,
 193         .size           = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
 194         .eval           = nft_nat_eval,
 195         .init           = nft_nat_init,
 196         .dump           = nft_nat_dump,
 197 };
 198
 199 static struct nft_expr_type nft_nat_type __read_mostly = {
 200         .name           = "nat",
 201         .ops            = &nft_nat_ops,
 202         .policy         = nft_nat_policy,
 203         .maxattr        = NFTA_NAT_MAX,
 204         .owner          = THIS_MODULE,
 205 };
 206
 207 static int __init nft_nat_module_init(void)
 208 {
 209         return nft_register_expr(&nft_nat_type);
 210 }
 211
 212 static void __exit nft_nat_module_exit(void)
 213 {
 214         nft_unregister_expr(&nft_nat_type);
 215 }
 216
 217 module_init(nft_nat_module_init);
 218 module_exit(nft_nat_module_exit);
 219
 220 MODULE_LICENSE("GPL");
 221 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
 222 MODULE_ALIAS_NFT_EXPR("nat");