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         int                     family;
  35         enum nf_nat_manip_type  type;
  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         int err;
  92
  93         if (tb[NFTA_NAT_TYPE] == NULL)
  94                 return -EINVAL;
  95
  96         switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
  97         case NFT_NAT_SNAT:
  98                 priv->type = NF_NAT_MANIP_SRC;
  99                 break;
 100         case NFT_NAT_DNAT:
 101                 priv->type = NF_NAT_MANIP_DST;
 102                 break;
 103         default:
 104                 return -EINVAL;
 105         }
 106
 107         if (tb[NFTA_NAT_FAMILY] == NULL)
 108                 return -EINVAL;
 109
 110         priv->family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
 111         if (priv->family != AF_INET && priv->family != AF_INET6)
 112                 return -EINVAL;
 113
 114         if (tb[NFTA_NAT_REG_ADDR_MIN]) {
 115                 priv->sreg_addr_min = ntohl(nla_get_be32(
 116                                                 tb[NFTA_NAT_REG_ADDR_MIN]));
 117                 err = nft_validate_input_register(priv->sreg_addr_min);
 118                 if (err < 0)
 119                         return err;
 120         }
 121
 122         if (tb[NFTA_NAT_REG_ADDR_MAX]) {
 123                 priv->sreg_addr_max = ntohl(nla_get_be32(
 124                                                 tb[NFTA_NAT_REG_ADDR_MAX]));
 125                 err = nft_validate_input_register(priv->sreg_addr_max);
 126                 if (err < 0)
 127                         return err;
 128         } else
 129                 priv->sreg_addr_max = priv->sreg_addr_min;
 130
 131         if (tb[NFTA_NAT_REG_PROTO_MIN]) {
 132                 priv->sreg_proto_min = ntohl(nla_get_be32(
 133                                                 tb[NFTA_NAT_REG_PROTO_MIN]));
 134                 err = nft_validate_input_register(priv->sreg_proto_min);
 135                 if (err < 0)
 136                         return err;
 137         }
 138
 139         if (tb[NFTA_NAT_REG_PROTO_MAX]) {
 140                 priv->sreg_proto_max = ntohl(nla_get_be32(
 141                                                 tb[NFTA_NAT_REG_PROTO_MAX]));
 142                 err = nft_validate_input_register(priv->sreg_proto_max);
 143                 if (err < 0)
 144                         return err;
 145         } else
 146                 priv->sreg_proto_max = priv->sreg_proto_min;
 147
 148         return 0;
 149 }
 150
 151 static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
 152 {
 153         const struct nft_nat *priv = nft_expr_priv(expr);
 154
 155         switch (priv->type) {
 156         case NF_NAT_MANIP_SRC:
 157                 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
 158                         goto nla_put_failure;
 159                 break;
 160         case NF_NAT_MANIP_DST:
 161                 if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
 162                         goto nla_put_failure;
 163                 break;
 164         }
 165
 166         if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
 167                 goto nla_put_failure;
 168         if (nla_put_be32(skb,
 169                          NFTA_NAT_REG_ADDR_MIN, htonl(priv->sreg_addr_min)))
 170                 goto nla_put_failure;
 171         if (nla_put_be32(skb,
 172                          NFTA_NAT_REG_ADDR_MAX, htonl(priv->sreg_addr_max)))
 173                 goto nla_put_failure;
 174         if (nla_put_be32(skb,
 175                          NFTA_NAT_REG_PROTO_MIN, htonl(priv->sreg_proto_min)))
 176                 goto nla_put_failure;
 177         if (nla_put_be32(skb,
 178                          NFTA_NAT_REG_PROTO_MAX, htonl(priv->sreg_proto_max)))
 179                 goto nla_put_failure;
 180         return 0;
 181
 182 nla_put_failure:
 183         return -1;
 184 }
 185
 186 static struct nft_expr_type nft_nat_type;
 187 static const struct nft_expr_ops nft_nat_ops = {
 188         .type           = &nft_nat_type,
 189         .size           = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
 190         .eval           = nft_nat_eval,
 191         .init           = nft_nat_init,
 192         .dump           = nft_nat_dump,
 193 };
 194
 195 static struct nft_expr_type nft_nat_type __read_mostly = {
 196         .name           = "nat",
 197         .ops            = &nft_nat_ops,
 198         .policy         = nft_nat_policy,
 199         .maxattr        = NFTA_NAT_MAX,
 200         .owner          = THIS_MODULE,
 201 };
 202
 203 static int __init nft_nat_module_init(void)
 204 {
 205         int err;
 206
 207         err = nft_register_expr(&nft_nat_type);
 208         if (err < 0)
 209                 return err;
 210
 211         return 0;
 212 }
 213
 214 static void __exit nft_nat_module_exit(void)
 215 {
 216         nft_unregister_expr(&nft_nat_type);
 217 }
 218
 219 module_init(nft_nat_module_init);
 220 module_exit(nft_nat_module_exit);
 221
 222 MODULE_LICENSE("GPL");
 223 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
 224 MODULE_ALIAS_NFT_EXPR("nat");