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_in: skb, ICMPV6_NOROUTE, hooknum: xt_hooknum(par));
43 break;
44 case IP6T_ICMP6_ADM_PROHIBITED:
45 nf_send_unreach6(net, skb_in: skb, ICMPV6_ADM_PROHIBITED,
46 hooknum: xt_hooknum(par));
47 break;
48 case IP6T_ICMP6_NOT_NEIGHBOUR:
49 nf_send_unreach6(net, skb_in: skb, ICMPV6_NOT_NEIGHBOUR,
50 hooknum: xt_hooknum(par));
51 break;
52 case IP6T_ICMP6_ADDR_UNREACH:
53 nf_send_unreach6(net, skb_in: skb, ICMPV6_ADDR_UNREACH,
54 hooknum: xt_hooknum(par));
55 break;
56 case IP6T_ICMP6_PORT_UNREACH:
57 nf_send_unreach6(net, skb_in: skb, ICMPV6_PORT_UNREACH,
58 hooknum: 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, sk: par->state->sk, oldskb: skb, hook: xt_hooknum(par));
65 break;
66 case IP6T_ICMP6_POLICY_FAIL:
67 nf_send_unreach6(net, skb_in: skb, ICMPV6_POLICY_FAIL, hooknum: xt_hooknum(par));
68 break;
69 case IP6T_ICMP6_REJECT_ROUTE:
70 nf_send_unreach6(net, skb_in: skb, ICMPV6_REJECT_ROUTE,
71 hooknum: 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(target: &reject_tg6_reg);
113}
114
115static void __exit reject_tg6_exit(void)
116{
117 xt_unregister_target(target: &reject_tg6_reg);
118}
119
120module_init(reject_tg6_init);
121module_exit(reject_tg6_exit);
122

source code of linux/net/ipv6/netfilter/ip6t_REJECT.c