libip6t_REJECT.c revision 0e2abed11985e16215559cefd90625f99317b96c 
1/* Shared library add-on to iptables 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 <ip6tables.h>
13#include <linux/netfilter_ipv6/ip6_tables.h>
14#include <linux/netfilter_ipv6/ip6t_REJECT.h>
15
16struct reject_names {
17	const char *name;
18	const char *alias;
19	enum ip6t_reject_with with;
20	const char *desc;
21};
22
23static const struct reject_names reject_table[] = {
24	{"icmp6-no-route", "no-route",
25		IP6T_ICMP6_NO_ROUTE, "ICMPv6 no route"},
26	{"icmp6-adm-prohibited", "adm-prohibited",
27		IP6T_ICMP6_ADM_PROHIBITED, "ICMPv6 administratively prohibited"},
28#if 0
29	{"icmp6-not-neighbor", "not-neighbor"},
30		IP6T_ICMP6_NOT_NEIGHBOR, "ICMPv6 not a neighbor"},
31#endif
32	{"icmp6-addr-unreachable", "addr-unreach",
33		IP6T_ICMP6_ADDR_UNREACH, "ICMPv6 address unreachable"},
34	{"icmp6-port-unreachable", "port-unreach",
35		IP6T_ICMP6_PORT_UNREACH, "ICMPv6 port unreachable"},
36	{"tcp-reset", "tcp-reset",
37		IP6T_TCP_RESET, "TCP RST packet"}
38};
39
40static void
41print_reject_types(void)
42{
43	unsigned int i;
44
45	printf("Valid reject types:\n");
46
47	for (i = 0; i < sizeof(reject_table)/sizeof(struct reject_names); i++) {
48		printf("    %-25s\t%s\n", reject_table[i].name, reject_table[i].desc);
49		printf("    %-25s\talias\n", reject_table[i].alias);
50	}
51	printf("\n");
52}
53
54/* Saves the union ipt_targinfo in parsable form to stdout. */
55
56/* Function which prints out usage message. */
57static void
58help(void)
59{
60	printf(
61"REJECT options:\n"
62"--reject-with type              drop input packet and send back\n"
63"                                a reply packet according to type:\n");
64
65	print_reject_types();
66}
67
68static const struct option opts[] = {
69	{ "reject-with", 1, NULL, '1' },
70	{ }
71};
72
73/* Allocate and initialize the target. */
74static void
75init(struct xt_entry_target *t)
76{
77	struct ip6t_reject_info *reject = (struct ip6t_reject_info *)t->data;
78
79	/* default */
80	reject->with = IP6T_ICMP6_PORT_UNREACH;
81
82}
83
84/* Function which parses command options; returns true if it
85   ate an option */
86static int
87parse(int c, char **argv, int invert, unsigned int *flags,
88      const void *entry,
89      struct xt_entry_target **target)
90{
91	struct ip6t_reject_info *reject =
92		(struct ip6t_reject_info *)(*target)->data;
93	unsigned int limit = sizeof(reject_table)/sizeof(struct reject_names);
94	unsigned int i;
95
96	switch(c) {
97	case '1':
98		if (check_inverse(optarg, &invert, NULL, 0))
99			exit_error(PARAMETER_PROBLEM,
100				   "Unexpected `!' after --reject-with");
101		for (i = 0; i < limit; i++) {
102			if ((strncasecmp(reject_table[i].name, optarg, strlen(optarg)) == 0)
103			    || (strncasecmp(reject_table[i].alias, optarg, strlen(optarg)) == 0)) {
104				reject->with = reject_table[i].with;
105				return 1;
106			}
107		}
108		exit_error(PARAMETER_PROBLEM, "unknown reject type `%s'",optarg);
109	default:
110		/* Fall through */
111		break;
112	}
113	return 0;
114}
115
116/* Prints out ipt_reject_info. */
117static void
118print(const void *ip,
119      const struct xt_entry_target *target,
120      int numeric)
121{
122	const struct ip6t_reject_info *reject
123		= (const struct ip6t_reject_info *)target->data;
124	unsigned int i;
125
126	for (i = 0; i < sizeof(reject_table)/sizeof(struct reject_names); i++) {
127		if (reject_table[i].with == reject->with)
128			break;
129	}
130	printf("reject-with %s ", reject_table[i].name);
131}
132
133/* Saves ipt_reject in parsable form to stdout. */
134static void save(const void *ip,
135		 const struct xt_entry_target *target)
136{
137	const struct ip6t_reject_info *reject
138		= (const struct ip6t_reject_info *)target->data;
139	unsigned int i;
140
141	for (i = 0; i < sizeof(reject_table)/sizeof(struct reject_names); i++)
142		if (reject_table[i].with == reject->with)
143			break;
144
145	printf("--reject-with %s ", reject_table[i].name);
146}
147
148static struct ip6tables_target reject = {
149	.name = "REJECT",
150	.version	= IPTABLES_VERSION,
151	.size 		= IP6T_ALIGN(sizeof(struct ip6t_reject_info)),
152	.userspacesize 	= IP6T_ALIGN(sizeof(struct ip6t_reject_info)),
153	.help		= &help,
154	.init		= &init,
155	.parse		= &parse,
156	.print		= &print,
157	.save		= &save,
158	.extra_opts	= opts,
159};
160
161void _init(void)
162{
163	register_target6(&reject);
164}
165