summaryrefslogtreecommitdiffstats
path: root/extensions/libip6t_icmp6.c
blob: b87538f9b34a7dfdad3e5e23ade26fbefd3ea5db (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
/* Shared library add-on to ip6tables to add ICMP support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <xtables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>

struct icmpv6_names {
	const char *name;
	u_int8_t type;
	u_int8_t code_min, code_max;
};

static const struct icmpv6_names icmpv6_codes[] = {
	{ "destination-unreachable", 1, 0, 0xFF },
	{   "no-route", 1, 0, 0 },
	{   "communication-prohibited", 1, 1, 1 },
	{   "address-unreachable", 1, 3, 3 },
	{   "port-unreachable", 1, 4, 4 },

	{ "packet-too-big", 2, 0, 0xFF },

	{ "time-exceeded", 3, 0, 0xFF },
	/* Alias */ { "ttl-exceeded", 3, 0, 0xFF },
	{   "ttl-zero-during-transit", 3, 0, 0 },
	{   "ttl-zero-during-reassembly", 3, 1, 1 },

	{ "parameter-problem", 4, 0, 0xFF },
	{   "bad-header", 4, 0, 0 },
	{   "unknown-header-type", 4, 1, 1 },
	{   "unknown-option", 4, 2, 2 },

	{ "echo-request", 128, 0, 0xFF },
	/* Alias */ { "ping", 128, 0, 0xFF },

	{ "echo-reply", 129, 0, 0xFF },
	/* Alias */ { "pong", 129, 0, 0xFF },

	{ "router-solicitation", 133, 0, 0xFF },

	{ "router-advertisement", 134, 0, 0xFF },

	{ "neighbour-solicitation", 135, 0, 0xFF },
	/* Alias */ { "neighbor-solicitation", 135, 0, 0xFF },

	{ "neighbour-advertisement", 136, 0, 0xFF },
	/* Alias */ { "neighbor-advertisement", 136, 0, 0xFF },

	{ "redirect", 137, 0, 0xFF },

};

static void
print_icmpv6types(void)
{
	unsigned int i;
	printf("Valid ICMPv6 Types:");

	for (i = 0; i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names); i++) {
		if (i && icmpv6_codes[i].type == icmpv6_codes[i-1].type) {
			if (icmpv6_codes[i].code_min == icmpv6_codes[i-1].code_min
			    && (icmpv6_codes[i].code_max
				== icmpv6_codes[i-1].code_max))
				printf(" (%s)", icmpv6_codes[i].name);
			else
				printf("\n   %s", icmpv6_codes[i].name);
		}
		else
			printf("\n%s", icmpv6_codes[i].name);
	}
	printf("\n");
}

static void icmp6_help(void)
{
	printf(
"icmpv6 match options:\n"
"[!] --icmpv6-type typename	match icmpv6 type\n"
"				(or numeric type or type/code)\n");
	print_icmpv6types();
}

static const struct option icmp6_opts[] = {
	{ "icmpv6-type", 1, NULL, '1' },
	{ .name = NULL }
};

static void
parse_icmpv6(const char *icmpv6type, u_int8_t *type, u_int8_t code[])
{
	unsigned int limit = sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
	unsigned int match = limit;
	unsigned int i;

	for (i = 0; i < limit; i++) {
		if (strncasecmp(icmpv6_codes[i].name, icmpv6type, strlen(icmpv6type))
		    == 0) {
			if (match != limit)
				exit_error(PARAMETER_PROBLEM,
					   "Ambiguous ICMPv6 type `%s':"
					   " `%s' or `%s'?",
					   icmpv6type,
					   icmpv6_codes[match].name,
					   icmpv6_codes[i].name);
			match = i;
		}
	}

	if (match != limit) {
		*type = icmpv6_codes[match].type;
		code[0] = icmpv6_codes[match].code_min;
		code[1] = icmpv6_codes[match].code_max;
	} else {
		char *slash;
		char buffer[strlen(icmpv6type) + 1];
		unsigned int number;

		strcpy(buffer, icmpv6type);
		slash = strchr(buffer, '/');

		if (slash)
			*slash = '\0';

		if (string_to_number(buffer, 0, 255, &number) == -1)
			exit_error(PARAMETER_PROBLEM,
				   "Invalid ICMPv6 type `%s'\n", buffer);
		*type = number;
		if (slash) {
			if (string_to_number(slash+1, 0, 255, &number) == -1)
				exit_error(PARAMETER_PROBLEM,
					   "Invalid ICMPv6 code `%s'\n",
					   slash+1);
			code[0] = code[1] = number;
		} else {
			code[0] = 0;
			code[1] = 0xFF;
		}
	}
}

static void icmp6_init(struct xt_entry_match *m)
{
	struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)m->data;

	icmpv6info->code[1] = 0xFF;
}

static int icmp6_parse(int c, char **argv, int invert, unsigned int *flags,
                       const void *entry, struct xt_entry_match **match)
{
	struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)(*match)->data;

	switch (c) {
	case '1':
		if (*flags == 1)
			exit_error(PARAMETER_PROBLEM,
				   "icmpv6 match: only use --icmpv6-type once!");
		check_inverse(optarg, &invert, &optind, 0);
		parse_icmpv6(argv[optind-1], &icmpv6info->type, 
			     icmpv6info->code);
		if (invert)
			icmpv6info->invflags |= IP6T_ICMP_INV;
		*flags = 1;
		break;

	default:
		return 0;
	}

	return 1;
}

static void print_icmpv6type(u_int8_t type,
			   u_int8_t code_min, u_int8_t code_max,
			   int invert,
			   int numeric)
{
	if (!numeric) {
		unsigned int i;

		for (i = 0;
		     i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
		     i++) {
			if (icmpv6_codes[i].type == type
			    && icmpv6_codes[i].code_min == code_min
			    && icmpv6_codes[i].code_max == code_max)
				break;
		}

		if (i != sizeof(icmpv6_codes)/sizeof(struct icmpv6_names)) {
			printf("%s%s ",
			       invert ? "!" : "",
			       icmpv6_codes[i].name);
			return;
		}
	}

	if (invert)
		printf("!");

	printf("type %u", type);
	if (code_min == 0 && code_max == 0xFF)
		printf(" ");
	else if (code_min == code_max)
		printf(" code %u ", code_min);
	else
		printf(" codes %u-%u ", code_min, code_max);
}

static void icmp6_print(const void *ip, const struct xt_entry_match *match,
                        int numeric)
{
	const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;

	printf("ipv6-icmp ");
	print_icmpv6type(icmpv6->type, icmpv6->code[0], icmpv6->code[1],
		       icmpv6->invflags & IP6T_ICMP_INV,
		       numeric);

	if (icmpv6->invflags & ~IP6T_ICMP_INV)
		printf("Unknown invflags: 0x%X ",
		       icmpv6->invflags & ~IP6T_ICMP_INV);
}

static void icmp6_save(const void *ip, const struct xt_entry_match *match)
{
	const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;

	if (icmpv6->invflags & IP6T_ICMP_INV)
		printf("! ");

	printf("--icmpv6-type %u", icmpv6->type);
	if (icmpv6->code[0] != 0 || icmpv6->code[1] != 0xFF)
		printf("/%u", icmpv6->code[0]);
	printf(" ");
}

static void icmp6_check(unsigned int flags)
{
	if (!flags)
		exit_error(PARAMETER_PROBLEM,
			   "icmpv6 match: You must specify `--icmpv6-type'");
}

static struct xtables_match icmp6_mt6_reg = {
	.name 		= "icmp6",
	.version 	= XTABLES_VERSION,
	.family		= NFPROTO_IPV6,
	.size		= XT_ALIGN(sizeof(struct ip6t_icmp)),
	.userspacesize	= XT_ALIGN(sizeof(struct ip6t_icmp)),
	.help		= icmp6_help,
	.init		= icmp6_init,
	.parse		= icmp6_parse,
	.final_check	= icmp6_check,
	.print		= icmp6_print,
	.save		= icmp6_save,
	.extra_opts	= icmp6_opts,
};

void _init(void)
{
	xtables_register_match(&icmp6_mt6_reg);
}