libip6t_REJECT.c revision 2c69b55e55f2efc5a334b87ccdceaa9de0ecb658 
1/* Shared library add-on to ip6tables to add customized REJECT support.
2 *
3 * (C) 2000 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
4 *
5 * ported to IPv6 by Harald Welte <laforge@gnumonks.org>
6 *
7 */
8#include <stdio.h>
9#include <string.h>
10#include <stdlib.h>
11#include <getopt.h>
12#include <xtables.h>
13#include <linux/netfilter_ipv6/ip6t_REJECT.h>
14
15struct reject_names {
16	const char *name;
17	const char *alias;
18	enum ip6t_reject_with with;
19	const char *desc;
20};
21
22static const struct reject_names reject_table[] = {
23	{"icmp6-no-route", "no-route",
24		IP6T_ICMP6_NO_ROUTE, "ICMPv6 no route"},
25	{"icmp6-adm-prohibited", "adm-prohibited",
26		IP6T_ICMP6_ADM_PROHIBITED, "ICMPv6 administratively prohibited"},
27#if 0
28	{"icmp6-not-neighbor", "not-neighbor"},
29		IP6T_ICMP6_NOT_NEIGHBOR, "ICMPv6 not a neighbor"},
30#endif
31	{"icmp6-addr-unreachable", "addr-unreach",
32		IP6T_ICMP6_ADDR_UNREACH, "ICMPv6 address unreachable"},
33	{"icmp6-port-unreachable", "port-unreach",
34		IP6T_ICMP6_PORT_UNREACH, "ICMPv6 port unreachable"},
35	{"tcp-reset", "tcp-reset",
36		IP6T_TCP_RESET, "TCP RST packet"}
37};
38
39static void
40print_reject_types(void)
41{
42	unsigned int i;
43
44	printf("Valid reject types:\n");
45
46	for (i = 0; i < ARRAY_SIZE(reject_table); ++i) {
47		printf("    %-25s\t%s\n", reject_table[i].name, reject_table[i].desc);
48		printf("    %-25s\talias\n", reject_table[i].alias);
49	}
50	printf("\n");
51}
52
53static void REJECT_help(void)
54{
55	printf(
56"REJECT target options:\n"
57"--reject-with type              drop input packet and send back\n"
58"                                a reply packet according to type:\n");
59
60	print_reject_types();
61}
62
63static const struct option REJECT_opts[] = {
64	{ "reject-with", 1, NULL, '1' },
65	{ .name = NULL }
66};
67
68static void REJECT_init(struct xt_entry_target *t)
69{
70	struct ip6t_reject_info *reject = (struct ip6t_reject_info *)t->data;
71
72	/* default */
73	reject->with = IP6T_ICMP6_PORT_UNREACH;
74
75}
76
77static int REJECT_parse(int c, char **argv, int invert, unsigned int *flags,
78                        const void *entry, struct xt_entry_target **target)
79{
80	struct ip6t_reject_info *reject =
81		(struct ip6t_reject_info *)(*target)->data;
82	unsigned int i;
83
84	switch(c) {
85	case '1':
86		if (xtables_check_inverse(optarg, &invert, NULL, 0))
87			xtables_error(PARAMETER_PROBLEM,
88				   "Unexpected `!' after --reject-with");
89		for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
90			if ((strncasecmp(reject_table[i].name, optarg, strlen(optarg)) == 0)
91			    || (strncasecmp(reject_table[i].alias, optarg, strlen(optarg)) == 0)) {
92				reject->with = reject_table[i].with;
93				return 1;
94			}
95		xtables_error(PARAMETER_PROBLEM, "unknown reject type \"%s\"", optarg);
96	default:
97		/* Fall through */
98		break;
99	}
100	return 0;
101}
102
103static void REJECT_print(const void *ip, const struct xt_entry_target *target,
104                         int numeric)
105{
106	const struct ip6t_reject_info *reject
107		= (const struct ip6t_reject_info *)target->data;
108	unsigned int i;
109
110	for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
111		if (reject_table[i].with == reject->with)
112			break;
113	printf("reject-with %s ", reject_table[i].name);
114}
115
116static void REJECT_save(const void *ip, const struct xt_entry_target *target)
117{
118	const struct ip6t_reject_info *reject
119		= (const struct ip6t_reject_info *)target->data;
120	unsigned int i;
121
122	for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
123		if (reject_table[i].with == reject->with)
124			break;
125
126	printf("--reject-with %s ", reject_table[i].name);
127}
128
129static struct xtables_target reject_tg6_reg = {
130	.name = "REJECT",
131	.version	= XTABLES_VERSION,
132	.family		= NFPROTO_IPV6,
133	.size 		= XT_ALIGN(sizeof(struct ip6t_reject_info)),
134	.userspacesize 	= XT_ALIGN(sizeof(struct ip6t_reject_info)),
135	.help		= REJECT_help,
136	.init		= REJECT_init,
137	.parse		= REJECT_parse,
138	.print		= REJECT_print,
139	.save		= REJECT_save,
140	.extra_opts	= REJECT_opts,
141};
142
143void _init(void)
144{
145	xtables_register_target(&reject_tg6_reg);
146}
147