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