nft_reject_ipv4.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
 4 * Copyright (c) 2013 Eric Leblond <eric@regit.org>
 5 *
 6 * Development of this code funded by Astaro AG (http://www.astaro.com/)
 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_reject.h>
17#include <net/netfilter/nft_reject.h>
18
19static void nft_reject_ipv4_eval(const struct nft_expr *expr,
20				 struct nft_regs *regs,
21				 const struct nft_pktinfo *pkt)
22{
23	struct nft_reject *priv = nft_expr_priv(expr);
24
25	switch (priv->type) {
26	case NFT_REJECT_ICMP_UNREACH:
27		nf_send_unreach(pkt->skb, priv->icmp_code, nft_hook(pkt));
28		break;
29	case NFT_REJECT_TCP_RST:
30		nf_send_reset(nft_net(pkt), nft_sk(pkt), pkt->skb,
31			      nft_hook(pkt));
32		break;
33	default:
34		break;
35	}
36
37	regs->verdict.code = NF_DROP;
38}
39
40static struct nft_expr_type nft_reject_ipv4_type;
41static const struct nft_expr_ops nft_reject_ipv4_ops = {
42	.type		= &nft_reject_ipv4_type,
43	.size		= NFT_EXPR_SIZE(sizeof(struct nft_reject)),
44	.eval		= nft_reject_ipv4_eval,
45	.init		= nft_reject_init,
46	.dump		= nft_reject_dump,
47	.validate	= nft_reject_validate,
48	.reduce		= NFT_REDUCE_READONLY,
49};
50
51static struct nft_expr_type nft_reject_ipv4_type __read_mostly = {
52	.family		= NFPROTO_IPV4,
53	.name		= "reject",
54	.ops		= &nft_reject_ipv4_ops,
55	.policy		= nft_reject_policy,
56	.maxattr	= NFTA_REJECT_MAX,
57	.owner		= THIS_MODULE,
58};
59
60static int __init nft_reject_ipv4_module_init(void)
61{
62	return nft_register_expr(&nft_reject_ipv4_type);
63}
64
65static void __exit nft_reject_ipv4_module_exit(void)
66{
67	nft_unregister_expr(&nft_reject_ipv4_type);
68}
69
70module_init(nft_reject_ipv4_module_init);
71module_exit(nft_reject_ipv4_module_exit);
72
73MODULE_LICENSE("GPL");
74MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
75MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "reject");
76MODULE_DESCRIPTION("IPv4 packet rejection for nftables");