net/netfilter/nft_fwd_netdev.c

   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/nf_dup_netdev.h>
  17
  18 struct nft_fwd_netdev {
  19         enum nft_registers      sreg_dev:8;
  20 };
  21
  22 static void nft_fwd_netdev_eval(const struct nft_expr *expr,
  23                                 struct nft_regs *regs,
  24                                 const struct nft_pktinfo *pkt)
  25 {
  26         struct nft_fwd_netdev *priv = nft_expr_priv(expr);
  27         int oif = regs->data[priv->sreg_dev];
  28
  29         nf_fwd_netdev_egress(pkt, oif);
  30         regs->verdict.code = NF_STOLEN;
  31 }
  32
  33 static const struct nla_policy nft_fwd_netdev_policy[NFTA_FWD_MAX + 1] = {
  34         [NFTA_FWD_SREG_DEV]     = { .type = NLA_U32 },
  35 };
  36
  37 static int nft_fwd_netdev_init(const struct nft_ctx *ctx,
  38                                const struct nft_expr *expr,
  39                                const struct nlattr * const tb[])
  40 {
  41         struct nft_fwd_netdev *priv = nft_expr_priv(expr);
  42
  43         if (tb[NFTA_FWD_SREG_DEV] == NULL)
  44                 return -EINVAL;
  45
  46         priv->sreg_dev = nft_parse_register(tb[NFTA_FWD_SREG_DEV]);
  47         return nft_validate_register_load(priv->sreg_dev, sizeof(int));
  48 }
  49
  50 static const struct nft_expr_ops nft_fwd_netdev_ingress_ops;
  51
  52 static int nft_fwd_netdev_dump(struct sk_buff *skb, const struct nft_expr *expr)
  53 {
  54         struct nft_fwd_netdev *priv = nft_expr_priv(expr);
  55
  56         if (nft_dump_register(skb, NFTA_FWD_SREG_DEV, priv->sreg_dev))
  57                 goto nla_put_failure;
  58
  59         return 0;
  60
  61 nla_put_failure:
  62         return -1;
  63 }
  64
  65 static struct nft_expr_type nft_fwd_netdev_type;
  66 static const struct nft_expr_ops nft_fwd_netdev_ops = {
  67         .type           = &nft_fwd_netdev_type,
  68         .size           = NFT_EXPR_SIZE(sizeof(struct nft_fwd_netdev)),
  69         .eval           = nft_fwd_netdev_eval,
  70         .init           = nft_fwd_netdev_init,
  71         .dump           = nft_fwd_netdev_dump,
  72 };
  73
  74 static struct nft_expr_type nft_fwd_netdev_type __read_mostly = {
  75         .family         = NFPROTO_NETDEV,
  76         .name           = "fwd",
  77         .ops            = &nft_fwd_netdev_ops,
  78         .policy         = nft_fwd_netdev_policy,
  79         .maxattr        = NFTA_FWD_MAX,
  80         .owner          = THIS_MODULE,
  81 };
  82
  83 static int __init nft_fwd_netdev_module_init(void)
  84 {
  85         return nft_register_expr(&nft_fwd_netdev_type);
  86 }
  87
  88 static void __exit nft_fwd_netdev_module_exit(void)
  89 {
  90         nft_unregister_expr(&nft_fwd_netdev_type);
  91 }
  92
  93 module_init(nft_fwd_netdev_module_init);
  94 module_exit(nft_fwd_netdev_module_exit);
  95
  96 MODULE_LICENSE("GPL");
  97 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
  98 MODULE_ALIAS_NFT_AF_EXPR(5, "fwd");