net/netfilter/nft_dup_netdev.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/init.h>
   8 #include <linux/module.h>
   9 #include <linux/netlink.h>
  10 #include <linux/netfilter.h>
  11 #include <linux/netfilter/nf_tables.h>
  12 #include <net/netfilter/nf_tables.h>
  13 #include <net/netfilter/nf_tables_offload.h>
  14 #include <net/netfilter/nf_dup_netdev.h>
  15
  16 struct nft_dup_netdev {
  17         u8      sreg_dev;
  18 };
  19
  20 static void nft_dup_netdev_eval(const struct nft_expr *expr,
  21                                 struct nft_regs *regs,
  22                                 const struct nft_pktinfo *pkt)
  23 {
  24         struct nft_dup_netdev *priv = nft_expr_priv(expr);
  25         int oif = regs->data[priv->sreg_dev];
  26
  27         nf_dup_netdev_egress(pkt, oif);
  28 }
  29
  30 static const struct nla_policy nft_dup_netdev_policy[NFTA_DUP_MAX + 1] = {
  31         [NFTA_DUP_SREG_DEV]     = { .type = NLA_U32 },
  32 };
  33
  34 static int nft_dup_netdev_init(const struct nft_ctx *ctx,
  35                                const struct nft_expr *expr,
  36                                const struct nlattr * const tb[])
  37 {
  38         struct nft_dup_netdev *priv = nft_expr_priv(expr);
  39
  40         if (tb[NFTA_DUP_SREG_DEV] == NULL)
  41                 return -EINVAL;
  42
  43         return nft_parse_register_load(ctx, tb[NFTA_DUP_SREG_DEV], &priv->sreg_dev,
  44                                        sizeof(int));
  45 }
  46
  47 static int nft_dup_netdev_dump(struct sk_buff *skb,
  48                                const struct nft_expr *expr, bool reset)
  49 {
  50         struct nft_dup_netdev *priv = nft_expr_priv(expr);
  51
  52         if (nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
  53                 goto nla_put_failure;
  54
  55         return 0;
  56
  57 nla_put_failure:
  58         return -1;
  59 }
  60
  61 static int nft_dup_netdev_offload(struct nft_offload_ctx *ctx,
  62                                   struct nft_flow_rule *flow,
  63                                   const struct nft_expr *expr)
  64 {
  65         const struct nft_dup_netdev *priv = nft_expr_priv(expr);
  66         int oif = ctx->regs[priv->sreg_dev].data.data[0];
  67
  68         return nft_fwd_dup_netdev_offload(ctx, flow, FLOW_ACTION_MIRRED, oif);
  69 }
  70
  71 static bool nft_dup_netdev_offload_action(const struct nft_expr *expr)
  72 {
  73         return true;
  74 }
  75
  76 static struct nft_expr_type nft_dup_netdev_type;
  77 static const struct nft_expr_ops nft_dup_netdev_ops = {
  78         .type           = &nft_dup_netdev_type,
  79         .size           = NFT_EXPR_SIZE(sizeof(struct nft_dup_netdev)),
  80         .eval           = nft_dup_netdev_eval,
  81         .init           = nft_dup_netdev_init,
  82         .dump           = nft_dup_netdev_dump,
  83         .reduce         = NFT_REDUCE_READONLY,
  84         .offload        = nft_dup_netdev_offload,
  85         .offload_action = nft_dup_netdev_offload_action,
  86 };
  87
  88 static struct nft_expr_type nft_dup_netdev_type __read_mostly = {
  89         .family         = NFPROTO_NETDEV,
  90         .name           = "dup",
  91         .ops            = &nft_dup_netdev_ops,
  92         .policy         = nft_dup_netdev_policy,
  93         .maxattr        = NFTA_DUP_MAX,
  94         .owner          = THIS_MODULE,
  95 };
  96
  97 static int __init nft_dup_netdev_module_init(void)
  98 {
  99         return nft_register_expr(&nft_dup_netdev_type);
 100 }
 101
 102 static void __exit nft_dup_netdev_module_exit(void)
 103 {
 104         nft_unregister_expr(&nft_dup_netdev_type);
 105 }
 106
 107 module_init(nft_dup_netdev_module_init);
 108 module_exit(nft_dup_netdev_module_exit);
 109
 110 MODULE_LICENSE("GPL");
 111 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 112 MODULE_ALIAS_NFT_AF_EXPR(5, "dup");
 113 MODULE_DESCRIPTION("nftables netdev packet duplication support");