LXR linux/net/ipv4/netfilter/nft_dup

   1/*
   2 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
   3 *
   4 * This program is free software; you can redistribute it and/or modify it
   5 * under the terms of the GNU General Public License version 2 as published by
   6 * 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/ipv4/nf_dup_ipv4.h>
  17
  18struct nft_dup_ipv4 {
  19        enum nft_registers      sreg_addr:8;
  20        enum nft_registers      sreg_dev:8;
  21};
  22
  23static void nft_dup_ipv4_eval(const struct nft_expr *expr,
  24                              struct nft_regs *regs,
  25                              const struct nft_pktinfo *pkt)
  26{
  27        struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
  28        struct in_addr gw = {
  29                .s_addr = (__force __be32)regs->data[priv->sreg_addr],
  30        };
  31        int oif = priv->sreg_dev ? regs->data[priv->sreg_dev] : -1;
  32
  33        nf_dup_ipv4(nft_net(pkt), pkt->skb, nft_hook(pkt), &gw, oif);
  34}
  35
  36static int nft_dup_ipv4_init(const struct nft_ctx *ctx,
  37                             const struct nft_expr *expr,
  38                             const struct nlattr * const tb[])
  39{
  40        struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
  41        int err;
  42
  43        if (tb[NFTA_DUP_SREG_ADDR] == NULL)
  44                return -EINVAL;
  45
  46        priv->sreg_addr = nft_parse_register(tb[NFTA_DUP_SREG_ADDR]);
  47        err = nft_validate_register_load(priv->sreg_addr, sizeof(struct in_addr));
  48        if (err < 0)
  49                return err;
  50
  51        if (tb[NFTA_DUP_SREG_DEV] != NULL) {
  52                priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]);
  53                return nft_validate_register_load(priv->sreg_dev, sizeof(int));
  54        }
  55        return 0;
  56}
  57
  58static int nft_dup_ipv4_dump(struct sk_buff *skb, const struct nft_expr *expr)
  59{
  60        struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
  61
  62        if (nft_dump_register(skb, NFTA_DUP_SREG_ADDR, priv->sreg_addr))
  63                goto nla_put_failure;
  64        if (priv->sreg_dev &&
  65            nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
  66                goto nla_put_failure;
  67
  68        return 0;
  69
  70nla_put_failure:
  71        return -1;
  72}
  73
  74static struct nft_expr_type nft_dup_ipv4_type;
  75static const struct nft_expr_ops nft_dup_ipv4_ops = {
  76        .type           = &nft_dup_ipv4_type,
  77        .size           = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv4)),
  78        .eval           = nft_dup_ipv4_eval,
  79        .init           = nft_dup_ipv4_init,
  80        .dump           = nft_dup_ipv4_dump,
  81};
  82
  83static const struct nla_policy nft_dup_ipv4_policy[NFTA_DUP_MAX + 1] = {
  84        [NFTA_DUP_SREG_ADDR]    = { .type = NLA_U32 },
  85        [NFTA_DUP_SREG_DEV]     = { .type = NLA_U32 },
  86};
  87
  88static struct nft_expr_type nft_dup_ipv4_type __read_mostly = {
  89        .family         = NFPROTO_IPV4,
  90        .name           = "dup",
  91        .ops            = &nft_dup_ipv4_ops,
  92        .policy         = nft_dup_ipv4_policy,
  93        .maxattr        = NFTA_DUP_MAX,
  94        .owner          = THIS_MODULE,
  95};
  96
  97static int __init nft_dup_ipv4_module_init(void)
  98{
  99        return nft_register_expr(&nft_dup_ipv4_type);
 100}
 101
 102static void __exit nft_dup_ipv4_module_exit(void)
 103{
 104        nft_unregister_expr(&nft_dup_ipv4_type);
 105}
 106
 107module_init(nft_dup_ipv4_module_init);
 108module_exit(nft_dup_ipv4_module_exit);
 109
 110MODULE_LICENSE("GPL");
 111MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 112MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "dup");
 113