libip6t_icmp6.c revision 8b7c64d6ba156a99008fcd810cba874c73294333 
1/* Shared library add-on to iptables to add ICMP support. */
2#include <stdio.h>
3#include <netdb.h>
4#include <string.h>
5#include <stdlib.h>
6#include <getopt.h>
7#include <ip6tables.h>
8#include <linux/netfilter_ipv6/ip6_tables.h>
9
10struct icmpv6_names {
11	const char *name;
12	u_int8_t type;
13	u_int8_t code_min, code_max;
14};
15
16static const struct icmpv6_names icmpv6_codes[] = {
17	{ "destination-unreachable", 1, 0, 0xFF },
18	{   "no-route", 1, 0, 0 },
19	{   "communication-prohibited", 1, 1, 1 },
20	{   "address-unreachable", 1, 3, 3 },
21	{   "port-unreachable", 1, 4, 4 },
22
23	{ "packet-too-big", 2, 0, 0xFF },
24
25	{ "time-exceeded", 3, 0, 0xFF },
26	/* Alias */ { "ttl-exceeded", 3, 0, 0xFF },
27	{   "ttl-zero-during-transit", 3, 0, 0 },
28	{   "ttl-zero-during-reassembly", 3, 1, 1 },
29
30	{ "parameter-problem", 4, 0, 0xFF },
31	{   "bad-header", 4, 0, 0 },
32	{   "unknown-header-type", 4, 1, 1 },
33	{   "unknown-option", 4, 2, 2 },
34
35	{ "echo-request", 128, 0, 0xFF },
36	/* Alias */ { "ping", 128, 0, 0xFF },
37
38	{ "echo-reply", 129, 0, 0xFF },
39	/* Alias */ { "pong", 129, 0, 0xFF },
40
41	{ "router-solicitation", 133, 0, 0xFF },
42
43	{ "router-advertisement", 134, 0, 0xFF },
44
45	{ "neighbour-solicitation", 135, 0, 0xFF },
46	/* Alias */ { "neighbor-solicitation", 135, 0, 0xFF },
47
48	{ "neighbour-advertisement", 136, 0, 0xFF },
49	/* Alias */ { "neighbor-advertisement", 136, 0, 0xFF },
50
51	{ "redirect", 137, 0, 0xFF },
52
53};
54
55static void
56print_icmpv6types(void)
57{
58	unsigned int i;
59	printf("Valid ICMPv6 Types:");
60
61	for (i = 0; i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names); i++) {
62		if (i && icmpv6_codes[i].type == icmpv6_codes[i-1].type) {
63			if (icmpv6_codes[i].code_min == icmpv6_codes[i-1].code_min
64			    && (icmpv6_codes[i].code_max
65				== icmpv6_codes[i-1].code_max))
66				printf(" (%s)", icmpv6_codes[i].name);
67			else
68				printf("\n   %s", icmpv6_codes[i].name);
69		}
70		else
71			printf("\n%s", icmpv6_codes[i].name);
72	}
73	printf("\n");
74}
75
76/* Function which prints out usage message. */
77static void icmp6_help(void)
78{
79	printf(
80"icmpv6 match options:\n"
81" --icmpv6-type [!] typename	match icmpv6 type\n"
82"				(or numeric type or type/code)\n");
83	print_icmpv6types();
84}
85
86static const struct option icmp6_opts[] = {
87	{ "icmpv6-type", 1, NULL, '1' },
88	{ .name = NULL }
89};
90
91static void
92parse_icmpv6(const char *icmpv6type, u_int8_t *type, u_int8_t code[])
93{
94	unsigned int limit = sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
95	unsigned int match = limit;
96	unsigned int i;
97
98	for (i = 0; i < limit; i++) {
99		if (strncasecmp(icmpv6_codes[i].name, icmpv6type, strlen(icmpv6type))
100		    == 0) {
101			if (match != limit)
102				exit_error(PARAMETER_PROBLEM,
103					   "Ambiguous ICMPv6 type `%s':"
104					   " `%s' or `%s'?",
105					   icmpv6type,
106					   icmpv6_codes[match].name,
107					   icmpv6_codes[i].name);
108			match = i;
109		}
110	}
111
112	if (match != limit) {
113		*type = icmpv6_codes[match].type;
114		code[0] = icmpv6_codes[match].code_min;
115		code[1] = icmpv6_codes[match].code_max;
116	} else {
117		char *slash;
118		char buffer[strlen(icmpv6type) + 1];
119		unsigned int number;
120
121		strcpy(buffer, icmpv6type);
122		slash = strchr(buffer, '/');
123
124		if (slash)
125			*slash = '\0';
126
127		if (string_to_number(buffer, 0, 255, &number) == -1)
128			exit_error(PARAMETER_PROBLEM,
129				   "Invalid ICMPv6 type `%s'\n", buffer);
130		*type = number;
131		if (slash) {
132			if (string_to_number(slash+1, 0, 255, &number) == -1)
133				exit_error(PARAMETER_PROBLEM,
134					   "Invalid ICMPv6 code `%s'\n",
135					   slash+1);
136			code[0] = code[1] = number;
137		} else {
138			code[0] = 0;
139			code[1] = 0xFF;
140		}
141	}
142}
143
144/* Initialize the match. */
145static void icmp6_init(struct xt_entry_match *m)
146{
147	struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)m->data;
148
149	icmpv6info->code[1] = 0xFF;
150}
151
152/* Function which parses command options; returns true if it
153   ate an option */
154static int icmp6_parse(int c, char **argv, int invert, unsigned int *flags,
155                       const void *entry, struct xt_entry_match **match)
156{
157	struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)(*match)->data;
158
159	switch (c) {
160	case '1':
161		if (*flags == 1)
162			exit_error(PARAMETER_PROBLEM,
163				   "icmpv6 match: only use --icmpv6-type once!");
164		check_inverse(optarg, &invert, &optind, 0);
165		parse_icmpv6(argv[optind-1], &icmpv6info->type,
166			     icmpv6info->code);
167		if (invert)
168			icmpv6info->invflags |= IP6T_ICMP_INV;
169		*flags = 1;
170		break;
171
172	default:
173		return 0;
174	}
175
176	return 1;
177}
178
179static void print_icmpv6type(u_int8_t type,
180			   u_int8_t code_min, u_int8_t code_max,
181			   int invert,
182			   int numeric)
183{
184	if (!numeric) {
185		unsigned int i;
186
187		for (i = 0;
188		     i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
189		     i++) {
190			if (icmpv6_codes[i].type == type
191			    && icmpv6_codes[i].code_min == code_min
192			    && icmpv6_codes[i].code_max == code_max)
193				break;
194		}
195
196		if (i != sizeof(icmpv6_codes)/sizeof(struct icmpv6_names)) {
197			printf("%s%s ",
198			       invert ? "!" : "",
199			       icmpv6_codes[i].name);
200			return;
201		}
202	}
203
204	if (invert)
205		printf("!");
206
207	printf("type %u", type);
208	if (code_min == 0 && code_max == 0xFF)
209		printf(" ");
210	else if (code_min == code_max)
211		printf(" code %u ", code_min);
212	else
213		printf(" codes %u-%u ", code_min, code_max);
214}
215
216/* Prints out the union ipt_matchinfo. */
217static void icmp6_print(const void *ip, const struct xt_entry_match *match,
218                        int numeric)
219{
220	const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
221
222	printf("ipv6-icmp ");
223	print_icmpv6type(icmpv6->type, icmpv6->code[0], icmpv6->code[1],
224		       icmpv6->invflags & IP6T_ICMP_INV,
225		       numeric);
226
227	if (icmpv6->invflags & ~IP6T_ICMP_INV)
228		printf("Unknown invflags: 0x%X ",
229		       icmpv6->invflags & ~IP6T_ICMP_INV);
230}
231
232/* Saves the match in parsable form to stdout. */
233static void icmp6_save(const void *ip, const struct xt_entry_match *match)
234{
235	const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
236
237	if (icmpv6->invflags & IP6T_ICMP_INV)
238		printf("! ");
239
240	printf("--icmpv6-type %u", icmpv6->type);
241	if (icmpv6->code[0] != 0 || icmpv6->code[1] != 0xFF)
242		printf("/%u", icmpv6->code[0]);
243	printf(" ");
244}
245
246static void icmp6_check(unsigned int flags)
247{
248	if (!flags)
249		exit_error(PARAMETER_PROBLEM,
250			   "icmpv6 match: You must specify `--icmpv6-type'");
251}
252
253static struct xtables_match icmp6_mt6_reg = {
254	.name 		= "icmp6",
255	.version 	= XTABLES_VERSION,
256	.family		= PF_INET6,
257	.size		= XT_ALIGN(sizeof(struct ip6t_icmp)),
258	.userspacesize	= XT_ALIGN(sizeof(struct ip6t_icmp)),
259	.help		= icmp6_help,
260	.init		= icmp6_init,
261	.parse		= icmp6_parse,
262	.final_check	= icmp6_check,
263	.print		= icmp6_print,
264	.save		= icmp6_save,
265	.extra_opts	= icmp6_opts,
266};
267
268void _init(void)
269{
270	xtables_register_match(&icmp6_mt6_reg);
271}
272