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
10 struct icmpv6_names {
11 const char *name;
12 u_int8_t type;
13 u_int8_t code_min, code_max;
14 };
15
16 static 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
55 static void
print_icmpv6types()56 print_icmpv6types()
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. */
77 static void
help(void)78 help(void)
79 {
80 printf(
81 "ICMPv6 v%s options:\n"
82 " --icmpv6-type [!] typename match icmpv6 type\n"
83 " (or numeric type or type/code)\n"
84 "\n", IPTABLES_VERSION);
85 print_icmpv6types();
86 }
87
88 static struct option opts[] = {
89 { "icmpv6-type", 1, 0, '1' },
90 {0}
91 };
92
93 static void
parse_icmpv6(const char * icmpv6type,u_int8_t * type,u_int8_t code[])94 parse_icmpv6(const char *icmpv6type, u_int8_t *type, u_int8_t code[])
95 {
96 unsigned int limit = sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
97 unsigned int match = limit;
98 unsigned int i;
99
100 for (i = 0; i < limit; i++) {
101 if (strncasecmp(icmpv6_codes[i].name, icmpv6type, strlen(icmpv6type))
102 == 0) {
103 if (match != limit)
104 exit_error(PARAMETER_PROBLEM,
105 "Ambiguous ICMPv6 type `%s':"
106 " `%s' or `%s'?",
107 icmpv6type,
108 icmpv6_codes[match].name,
109 icmpv6_codes[i].name);
110 match = i;
111 }
112 }
113
114 if (match != limit) {
115 *type = icmpv6_codes[match].type;
116 code[0] = icmpv6_codes[match].code_min;
117 code[1] = icmpv6_codes[match].code_max;
118 } else {
119 char *slash;
120 char buffer[strlen(icmpv6type) + 1];
121 unsigned int number;
122
123 strcpy(buffer, icmpv6type);
124 slash = strchr(buffer, '/');
125
126 if (slash)
127 *slash = '\0';
128
129 if (string_to_number(buffer, 0, 255, &number) == -1)
130 exit_error(PARAMETER_PROBLEM,
131 "Invalid ICMPv6 type `%s'\n", buffer);
132 *type = number;
133 if (slash) {
134 if (string_to_number(slash+1, 0, 255, &number) == -1)
135 exit_error(PARAMETER_PROBLEM,
136 "Invalid ICMPv6 code `%s'\n",
137 slash+1);
138 code[0] = code[1] = number;
139 } else {
140 code[0] = 0;
141 code[1] = 0xFF;
142 }
143 }
144 }
145
146 /* Initialize the match. */
147 static void
init(struct ip6t_entry_match * m,unsigned int * nfcache)148 init(struct ip6t_entry_match *m, unsigned int *nfcache)
149 {
150 struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)m->data;
151
152 icmpv6info->code[1] = 0xFF;
153 }
154
155 /* Function which parses command options; returns true if it
156 ate an option */
157 static int
parse(int c,char ** argv,int invert,unsigned int * flags,const struct ip6t_entry * entry,unsigned int * nfcache,struct ip6t_entry_match ** match)158 parse(int c, char **argv, int invert, unsigned int *flags,
159 const struct ip6t_entry *entry,
160 unsigned int *nfcache,
161 struct ip6t_entry_match **match)
162 {
163 struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)(*match)->data;
164
165 switch (c) {
166 case '1':
167 if (*flags == 1)
168 exit_error(PARAMETER_PROBLEM,
169 "icmpv6 match: only use --icmpv6-type once!");
170 check_inverse(optarg, &invert, &optind, 0);
171 parse_icmpv6(argv[optind-1], &icmpv6info->type,
172 icmpv6info->code);
173 if (invert)
174 icmpv6info->invflags |= IP6T_ICMP_INV;
175 *flags = 1;
176 break;
177
178 default:
179 return 0;
180 }
181
182 return 1;
183 }
184
print_icmpv6type(u_int8_t type,u_int8_t code_min,u_int8_t code_max,int invert,int numeric)185 static void print_icmpv6type(u_int8_t type,
186 u_int8_t code_min, u_int8_t code_max,
187 int invert,
188 int numeric)
189 {
190 if (!numeric) {
191 unsigned int i;
192
193 for (i = 0;
194 i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
195 i++) {
196 if (icmpv6_codes[i].type == type
197 && icmpv6_codes[i].code_min == code_min
198 && icmpv6_codes[i].code_max == code_max)
199 break;
200 }
201
202 if (i != sizeof(icmpv6_codes)/sizeof(struct icmpv6_names)) {
203 printf("%s%s ",
204 invert ? "!" : "",
205 icmpv6_codes[i].name);
206 return;
207 }
208 }
209
210 if (invert)
211 printf("!");
212
213 printf("type %u", type);
214 if (code_min == 0 && code_max == 0xFF)
215 printf(" ");
216 else if (code_min == code_max)
217 printf(" code %u ", code_min);
218 else
219 printf(" codes %u-%u ", code_min, code_max);
220 }
221
222 /* Prints out the union ipt_matchinfo. */
223 static void
print(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match,int numeric)224 print(const struct ip6t_ip6 *ip,
225 const struct ip6t_entry_match *match,
226 int numeric)
227 {
228 const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
229
230 printf("ipv6-icmp ");
231 print_icmpv6type(icmpv6->type, icmpv6->code[0], icmpv6->code[1],
232 icmpv6->invflags & IP6T_ICMP_INV,
233 numeric);
234
235 if (icmpv6->invflags & ~IP6T_ICMP_INV)
236 printf("Unknown invflags: 0x%X ",
237 icmpv6->invflags & ~IP6T_ICMP_INV);
238 }
239
240 /* Saves the match in parsable form to stdout. */
save(const struct ip6t_ip6 * ip,const struct ip6t_entry_match * match)241 static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
242 {
243 const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
244
245 if (icmpv6->invflags & IP6T_ICMP_INV)
246 printf("! ");
247
248 printf("--icmpv6-type %u", icmpv6->type);
249 if (icmpv6->code[0] != 0 || icmpv6->code[1] != 0xFF)
250 printf("/%u", icmpv6->code[0]);
251 printf(" ");
252 }
253
final_check(unsigned int flags)254 static void final_check(unsigned int flags)
255 {
256 if (!flags)
257 exit_error(PARAMETER_PROBLEM,
258 "icmpv6 match: You must specify `--icmpv6-type'");
259 }
260
261 static struct ip6tables_match icmpv6 = {
262 .name = "icmp6",
263 .version = IPTABLES_VERSION,
264 .size = IP6T_ALIGN(sizeof(struct ip6t_icmp)),
265 .userspacesize = IP6T_ALIGN(sizeof(struct ip6t_icmp)),
266 .help = &help,
267 .init = &init,
268 .parse = &parse,
269 .final_check = &final_check,
270 .print = &print,
271 .save = &save,
272 .extra_opts = opts,
273 };
274
_init(void)275 void _init(void)
276 {
277 register_match6(&icmpv6);
278 }
279