ip6t_REJECT.c

  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);