1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IP6 tables REJECT target module
4 * Linux INET6 implementation
5 *
6 * Copyright (C)2003 USAGI/WIDE Project
7 *
8 * Authors:
9 *	Yasuyuki Kozakai	<yasuyuki.kozakai@toshiba.co.jp>
10 *
11 * Copyright (c) 2005-2007 Patrick McHardy <kaber@trash.net>
12 *
13 * Based on net/ipv4/netfilter/ipt_REJECT.c
14 */
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/gfp.h>
18#include <linux/module.h>
19#include <linux/skbuff.h>
20#include <linux/icmpv6.h>
21#include <linux/netdevice.h>
22#include <net/icmp.h>
23#include <net/flow.h>
24#include <linux/netfilter/x_tables.h>
25#include <linux/netfilter_ipv6/ip6_tables.h>
26#include <linux/netfilter_ipv6/ip6t_REJECT.h>
27
28#include <net/netfilter/ipv6/nf_reject.h>
29
30MODULE_AUTHOR("Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>");
31MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv6");
32MODULE_LICENSE("GPL");
33
34static unsigned int
35reject_tg6(struct sk_buff *skb, const struct xt_action_param *par)
36{
37	const struct ip6t_reject_info *reject = par->targinfo;
38	struct net *net = xt_net(par);
39
40	switch (reject->with) {
41	case IP6T_ICMP6_NO_ROUTE:
42		nf_send_unreach6(net, skb, ICMPV6_NOROUTE, xt_hooknum(par));
43		break;
44	case IP6T_ICMP6_ADM_PROHIBITED:
45		nf_send_unreach6(net, skb, ICMPV6_ADM_PROHIBITED,
46				 xt_hooknum(par));
47		break;
48	case IP6T_ICMP6_NOT_NEIGHBOUR:
49		nf_send_unreach6(net, skb, ICMPV6_NOT_NEIGHBOUR,
50				 xt_hooknum(par));
51		break;
52	case IP6T_ICMP6_ADDR_UNREACH:
53		nf_send_unreach6(net, skb, ICMPV6_ADDR_UNREACH,
54				 xt_hooknum(par));
55		break;
56	case IP6T_ICMP6_PORT_UNREACH:
57		nf_send_unreach6(net, skb, ICMPV6_PORT_UNREACH,
58				 xt_hooknum(par));
59		break;
60	case IP6T_ICMP6_ECHOREPLY:
61		/* Do nothing */
62		break;
63	case IP6T_TCP_RESET:
64		nf_send_reset6(net, par->state->sk, skb, xt_hooknum(par));
65		break;
66	case IP6T_ICMP6_POLICY_FAIL:
67		nf_send_unreach6(net, skb, ICMPV6_POLICY_FAIL, xt_hooknum(par));
68		break;
69	case IP6T_ICMP6_REJECT_ROUTE:
70		nf_send_unreach6(net, skb, ICMPV6_REJECT_ROUTE,
71				 xt_hooknum(par));
72		break;
73	}
74
75	return NF_DROP;
76}
77
78static int reject_tg6_check(const struct xt_tgchk_param *par)
79{
80	const struct ip6t_reject_info *rejinfo = par->targinfo;
81	const struct ip6t_entry *e = par->entryinfo;
82
83	if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
84		pr_info_ratelimited("ECHOREPLY is not supported\n");
85		return -EINVAL;
86	} else if (rejinfo->with == IP6T_TCP_RESET) {
87		/* Must specify that it's a TCP packet */
88		if (!(e->ipv6.flags & IP6T_F_PROTO) ||
89		    e->ipv6.proto != IPPROTO_TCP ||
90		    (e->ipv6.invflags & XT_INV_PROTO)) {
91			pr_info_ratelimited("TCP_RESET illegal for non-tcp\n");
92			return -EINVAL;
93		}
94	}
95	return 0;
96}
97
98static struct xt_target reject_tg6_reg __read_mostly = {
99	.name		= "REJECT",
100	.family		= NFPROTO_IPV6,
101	.target		= reject_tg6,
102	.targetsize	= sizeof(struct ip6t_reject_info),
103	.table		= "filter",
104	.hooks		= (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
105			  (1 << NF_INET_LOCAL_OUT),
106	.checkentry	= reject_tg6_check,
107	.me		= THIS_MODULE
108};
109
110static int __init reject_tg6_init(void)
111{
112	return xt_register_target(&reject_tg6_reg);
113}
114
115static void __exit reject_tg6_exit(void)
116{
117	xt_unregister_target(&reject_tg6_reg);
118}
119
120module_init(reject_tg6_init);
121module_exit(reject_tg6_exit);
122