libip6t_REJECT.c revision 9ee386a1b6d7704b259460152c959ab0e79e02aa 
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 REJECT_help(void)
58{
59	printf(
60"REJECT options:\n"
61"--reject-with type              drop input packet and send back\n"
62"                                a reply packet according to type:\n");
63
64	print_reject_types();
65}
66
67static const struct option REJECT_opts[] = {
68	{ "reject-with", 1, NULL, '1' },
69	{ .name = NULL }
70};
71
72/* Allocate and initialize the target. */
73static void REJECT_init(struct xt_entry_target *t)
74{
75	struct ip6t_reject_info *reject = (struct ip6t_reject_info *)t->data;
76
77	/* default */
78	reject->with = IP6T_ICMP6_PORT_UNREACH;
79
80}
81
82/* Function which parses command options; returns true if it
83   ate an option */
84static int REJECT_parse(int c, char **argv, int invert, unsigned int *flags,
85                        const void *entry, struct xt_entry_target **target)
86{
87	struct ip6t_reject_info *reject =
88		(struct ip6t_reject_info *)(*target)->data;
89	unsigned int limit = sizeof(reject_table)/sizeof(struct reject_names);
90	unsigned int i;
91
92	switch(c) {
93	case '1':
94		if (check_inverse(optarg, &invert, NULL, 0))
95			exit_error(PARAMETER_PROBLEM,
96				   "Unexpected `!' after --reject-with");
97		for (i = 0; i < limit; i++) {
98			if ((strncasecmp(reject_table[i].name, optarg, strlen(optarg)) == 0)
99			    || (strncasecmp(reject_table[i].alias, optarg, strlen(optarg)) == 0)) {
100				reject->with = reject_table[i].with;
101				return 1;
102			}
103		}
104		exit_error(PARAMETER_PROBLEM, "unknown reject type `%s'",optarg);
105	default:
106		/* Fall through */
107		break;
108	}
109	return 0;
110}
111
112/* Prints out ipt_reject_info. */
113static void REJECT_print(const void *ip, const struct xt_entry_target *target,
114                         int numeric)
115{
116	const struct ip6t_reject_info *reject
117		= (const struct ip6t_reject_info *)target->data;
118	unsigned int i;
119
120	for (i = 0; i < sizeof(reject_table)/sizeof(struct reject_names); i++) {
121		if (reject_table[i].with == reject->with)
122			break;
123	}
124	printf("reject-with %s ", reject_table[i].name);
125}
126
127/* Saves ipt_reject in parsable form to stdout. */
128static void REJECT_save(const void *ip, const struct xt_entry_target *target)
129{
130	const struct ip6t_reject_info *reject
131		= (const struct ip6t_reject_info *)target->data;
132	unsigned int i;
133
134	for (i = 0; i < sizeof(reject_table)/sizeof(struct reject_names); i++)
135		if (reject_table[i].with == reject->with)
136			break;
137
138	printf("--reject-with %s ", reject_table[i].name);
139}
140
141static struct ip6tables_target reject_target6 = {
142	.name = "REJECT",
143	.version	= IPTABLES_VERSION,
144	.size 		= IP6T_ALIGN(sizeof(struct ip6t_reject_info)),
145	.userspacesize 	= IP6T_ALIGN(sizeof(struct ip6t_reject_info)),
146	.help		= REJECT_help,
147	.init		= REJECT_init,
148	.parse		= REJECT_parse,
149	.print		= REJECT_print,
150	.save		= REJECT_save,
151	.extra_opts	= REJECT_opts,
152};
153
154void _init(void)
155{
156	register_target6(&reject_target6);
157}
158