net/ipv4/netfilter/nft_redir_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/nf_nat.h>
  17 #include <net/netfilter/nf_nat_redirect.h>
  18 #include <net/netfilter/nft_redir.h>
  19
  20 static void nft_redir_ipv4_eval(const struct nft_expr *expr,
  21                                 struct nft_regs *regs,
  22                                 const struct nft_pktinfo *pkt)
  23 {
  24         struct nft_redir *priv = nft_expr_priv(expr);
  25         struct nf_nat_ipv4_multi_range_compat mr;
  26
  27         memset(&mr, 0, sizeof(mr));
  28         if (priv->sreg_proto_min) {
  29                 mr.range[0].min.all =
  30                         *(__be16 *)&regs->data[priv->sreg_proto_min];
  31                 mr.range[0].max.all =
  32                         *(__be16 *)&regs->data[priv->sreg_proto_max];
  33                 mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
  34         }
  35
  36         mr.range[0].flags |= priv->flags;
  37
  38         regs->verdict.code = nf_nat_redirect_ipv4(pkt->skb, &mr, nft_hook(pkt));
  39 }
  40
  41 static void
  42 nft_redir_ipv4_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
  43 {
  44         nf_ct_netns_put(ctx->net, NFPROTO_IPV4);
  45 }
  46
  47 static struct nft_expr_type nft_redir_ipv4_type;
  48 static const struct nft_expr_ops nft_redir_ipv4_ops = {
  49         .type           = &nft_redir_ipv4_type,
  50         .size           = NFT_EXPR_SIZE(sizeof(struct nft_redir)),
  51         .eval           = nft_redir_ipv4_eval,
  52         .init           = nft_redir_init,
  53         .destroy        = nft_redir_ipv4_destroy,
  54         .dump           = nft_redir_dump,
  55         .validate       = nft_redir_validate,
  56 };
  57
  58 static struct nft_expr_type nft_redir_ipv4_type __read_mostly = {
  59         .family         = NFPROTO_IPV4,
  60         .name           = "redir",
  61         .ops            = &nft_redir_ipv4_ops,
  62         .policy         = nft_redir_policy,
  63         .maxattr        = NFTA_REDIR_MAX,
  64         .owner          = THIS_MODULE,
  65 };
  66
  67 static int __init nft_redir_ipv4_module_init(void)
  68 {
  69         return nft_register_expr(&nft_redir_ipv4_type);
  70 }
  71
  72 static void __exit nft_redir_ipv4_module_exit(void)
  73 {
  74         nft_unregister_expr(&nft_redir_ipv4_type);
  75 }
  76
  77 module_init(nft_redir_ipv4_module_init);
  78 module_exit(nft_redir_ipv4_module_exit);
  79
  80 MODULE_LICENSE("GPL");
  81 MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>");
  82 MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "redir");