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
 16struct nft_dup_netdev {
 17	u8	sreg_dev;
 18};
 19
 20static 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
 30static const struct nla_policy nft_dup_netdev_policy[NFTA_DUP_MAX + 1] = {
 31	[NFTA_DUP_SREG_DEV]	= { .type = NLA_U32 },
 32};
 33
 34static 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
 47static 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
 57nla_put_failure:
 58	return -1;
 59}
 60
 61static 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
 71static bool nft_dup_netdev_offload_action(const struct nft_expr *expr)
 72{
 73	return true;
 74}
 75
 76static struct nft_expr_type nft_dup_netdev_type;
 77static 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
 88static 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
 97static int __init nft_dup_netdev_module_init(void)
 98{
 99	return nft_register_expr(&nft_dup_netdev_type);
100}
101
102static void __exit nft_dup_netdev_module_exit(void)
103{
104	nft_unregister_expr(&nft_dup_netdev_type);
105}
106
107module_init(nft_dup_netdev_module_init);
108module_exit(nft_dup_netdev_module_exit);
109
110MODULE_LICENSE("GPL");
111MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
112MODULE_ALIAS_NFT_AF_EXPR(5, "dup");
113MODULE_DESCRIPTION("nftables netdev packet duplication support");