net/ipv4/netfilter/nft_masq_ipv4.c

   1 /*
   2  * Copyright (c) 2014 Arturo Borrero Gonzalez <arturo@debian.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/netlink.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/nf_tables.h>
  15 #include <net/netfilter/nf_tables.h>
  16 #include <net/netfilter/nft_masq.h>
  17 #include <net/netfilter/ipv4/nf_nat_masquerade.h>
  18
  19 static void nft_masq_ipv4_eval(const struct nft_expr *expr,
  20                                struct nft_regs *regs,
  21                                const struct nft_pktinfo *pkt)
  22 {
  23         struct nft_masq *priv = nft_expr_priv(expr);
  24         struct nf_nat_range range;
  25
  26         memset(&range, 0, sizeof(range));
  27         range.flags = priv->flags;
  28         if (priv->sreg_proto_min) {
  29                 range.min_proto.all =
  30                         *(__be16 *)&regs->data[priv->sreg_proto_min];
  31                 range.max_proto.all =
  32                         *(__be16 *)&regs->data[priv->sreg_proto_max];
  33         }
  34         regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, nft_hook(pkt),
  35                                                     &range, nft_out(pkt));
  36 }
  37
  38 static void
  39 nft_masq_ipv4_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
  40 {
  41         nf_ct_netns_put(ctx->net, NFPROTO_IPV4);
  42 }
  43
  44 static struct nft_expr_type nft_masq_ipv4_type;
  45 static const struct nft_expr_ops nft_masq_ipv4_ops = {
  46         .type           = &nft_masq_ipv4_type,
  47         .size           = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
  48         .eval           = nft_masq_ipv4_eval,
  49         .init           = nft_masq_init,
  50         .destroy        = nft_masq_ipv4_destroy,
  51         .dump           = nft_masq_dump,
  52         .validate       = nft_masq_validate,
  53 };
  54
  55 static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
  56         .family         = NFPROTO_IPV4,
  57         .name           = "masq",
  58         .ops            = &nft_masq_ipv4_ops,
  59         .policy         = nft_masq_policy,
  60         .maxattr        = NFTA_MASQ_MAX,
  61         .owner          = THIS_MODULE,
  62 };
  63
  64 static int __init nft_masq_ipv4_module_init(void)
  65 {
  66         int ret;
  67
  68         ret = nft_register_expr(&nft_masq_ipv4_type);
  69         if (ret < 0)
  70                 return ret;
  71
  72         nf_nat_masquerade_ipv4_register_notifier();
  73
  74         return ret;
  75 }
  76
  77 static void __exit nft_masq_ipv4_module_exit(void)
  78 {
  79         nft_unregister_expr(&nft_masq_ipv4_type);
  80         nf_nat_masquerade_ipv4_unregister_notifier();
  81 }
  82
  83 module_init(nft_masq_ipv4_module_init);
  84 module_exit(nft_masq_ipv4_module_exit);
  85
  86 MODULE_LICENSE("GPL");
  87 MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org");
  88 MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "masq");