1 #include <stdint.h>
2 #include <stdio.h>
3 #include <string.h>
4 #include <xtables.h>
5 #include <limits.h> /* INT_MAX in ip6_tables.h */
6 #include <linux/netfilter_ipv6/ip6_tables.h>
7 #include <netinet/icmp6.h>
8
9 #include "libxt_icmp.h"
10
11 enum {
12 O_ICMPV6_TYPE = 0,
13 };
14
15 static const struct xt_icmp_names icmpv6_codes[] = {
16 { "destination-unreachable", 1, 0, 0xFF },
17 { "no-route", 1, 0, 0 },
18 { "communication-prohibited", 1, 1, 1 },
19 { "beyond-scope", 1, 2, 2 },
20 { "address-unreachable", 1, 3, 3 },
21 { "port-unreachable", 1, 4, 4 },
22 { "failed-policy", 1, 5, 5 },
23 { "reject-route", 1, 6, 6 },
24
25 { "packet-too-big", 2, 0, 0xFF },
26
27 { "time-exceeded", 3, 0, 0xFF },
28 /* Alias */ { "ttl-exceeded", 3, 0, 0xFF },
29 { "ttl-zero-during-transit", 3, 0, 0 },
30 { "ttl-zero-during-reassembly", 3, 1, 1 },
31
32 { "parameter-problem", 4, 0, 0xFF },
33 { "bad-header", 4, 0, 0 },
34 { "unknown-header-type", 4, 1, 1 },
35 { "unknown-option", 4, 2, 2 },
36
37 { "echo-request", 128, 0, 0xFF },
38 /* Alias */ { "ping", 128, 0, 0xFF },
39
40 { "echo-reply", 129, 0, 0xFF },
41 /* Alias */ { "pong", 129, 0, 0xFF },
42
43 { "router-solicitation", 133, 0, 0xFF },
44
45 { "router-advertisement", 134, 0, 0xFF },
46
47 { "neighbour-solicitation", 135, 0, 0xFF },
48 /* Alias */ { "neighbor-solicitation", 135, 0, 0xFF },
49
50 { "neighbour-advertisement", 136, 0, 0xFF },
51 /* Alias */ { "neighbor-advertisement", 136, 0, 0xFF },
52
53 { "redirect", 137, 0, 0xFF },
54
55 };
56
icmp6_help(void)57 static void icmp6_help(void)
58 {
59 printf(
60 "icmpv6 match options:\n"
61 "[!] --icmpv6-type typename match icmpv6 type\n"
62 " (or numeric type or type/code)\n");
63 printf("Valid ICMPv6 Types:");
64 xt_print_icmp_types(icmpv6_codes, ARRAY_SIZE(icmpv6_codes));
65 }
66
67 static const struct xt_option_entry icmp6_opts[] = {
68 {.name = "icmpv6-type", .id = O_ICMPV6_TYPE, .type = XTTYPE_STRING,
69 .flags = XTOPT_MAND | XTOPT_INVERT},
70 XTOPT_TABLEEND,
71 };
72
73 static void
parse_icmpv6(const char * icmpv6type,uint8_t * type,uint8_t code[])74 parse_icmpv6(const char *icmpv6type, uint8_t *type, uint8_t code[])
75 {
76 static const unsigned int limit = ARRAY_SIZE(icmpv6_codes);
77 unsigned int match = limit;
78 unsigned int i;
79
80 for (i = 0; i < limit; i++) {
81 if (strncasecmp(icmpv6_codes[i].name, icmpv6type, strlen(icmpv6type))
82 == 0) {
83 if (match != limit)
84 xtables_error(PARAMETER_PROBLEM,
85 "Ambiguous ICMPv6 type `%s':"
86 " `%s' or `%s'?",
87 icmpv6type,
88 icmpv6_codes[match].name,
89 icmpv6_codes[i].name);
90 match = i;
91 }
92 }
93
94 if (match != limit) {
95 *type = icmpv6_codes[match].type;
96 code[0] = icmpv6_codes[match].code_min;
97 code[1] = icmpv6_codes[match].code_max;
98 } else {
99 char *slash;
100 char buffer[strlen(icmpv6type) + 1];
101 unsigned int number;
102
103 strcpy(buffer, icmpv6type);
104 slash = strchr(buffer, '/');
105
106 if (slash)
107 *slash = '\0';
108
109 if (!xtables_strtoui(buffer, NULL, &number, 0, UINT8_MAX))
110 xtables_error(PARAMETER_PROBLEM,
111 "Invalid ICMPv6 type `%s'\n", buffer);
112 *type = number;
113 if (slash) {
114 if (!xtables_strtoui(slash+1, NULL, &number, 0, UINT8_MAX))
115 xtables_error(PARAMETER_PROBLEM,
116 "Invalid ICMPv6 code `%s'\n",
117 slash+1);
118 code[0] = code[1] = number;
119 } else {
120 code[0] = 0;
121 code[1] = 0xFF;
122 }
123 }
124 }
125
icmp6_init(struct xt_entry_match * m)126 static void icmp6_init(struct xt_entry_match *m)
127 {
128 struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)m->data;
129
130 icmpv6info->code[1] = 0xFF;
131 }
132
icmp6_parse(struct xt_option_call * cb)133 static void icmp6_parse(struct xt_option_call *cb)
134 {
135 struct ip6t_icmp *icmpv6info = cb->data;
136
137 xtables_option_parse(cb);
138 parse_icmpv6(cb->arg, &icmpv6info->type, icmpv6info->code);
139 if (cb->invert)
140 icmpv6info->invflags |= IP6T_ICMP_INV;
141 }
142
print_icmpv6type(uint8_t type,uint8_t code_min,uint8_t code_max,int invert,int numeric)143 static void print_icmpv6type(uint8_t type,
144 uint8_t code_min, uint8_t code_max,
145 int invert,
146 int numeric)
147 {
148 if (!numeric) {
149 unsigned int i;
150
151 for (i = 0; i < ARRAY_SIZE(icmpv6_codes); ++i)
152 if (icmpv6_codes[i].type == type
153 && icmpv6_codes[i].code_min == code_min
154 && icmpv6_codes[i].code_max == code_max)
155 break;
156
157 if (i != ARRAY_SIZE(icmpv6_codes)) {
158 printf(" %s%s",
159 invert ? "!" : "",
160 icmpv6_codes[i].name);
161 return;
162 }
163 }
164
165 if (invert)
166 printf(" !");
167
168 printf("type %u", type);
169 if (code_min == code_max)
170 printf(" code %u", code_min);
171 else if (code_min != 0 || code_max != 0xFF)
172 printf(" codes %u-%u", code_min, code_max);
173 }
174
icmp6_print(const void * ip,const struct xt_entry_match * match,int numeric)175 static void icmp6_print(const void *ip, const struct xt_entry_match *match,
176 int numeric)
177 {
178 const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
179
180 printf(" ipv6-icmp");
181 print_icmpv6type(icmpv6->type, icmpv6->code[0], icmpv6->code[1],
182 icmpv6->invflags & IP6T_ICMP_INV,
183 numeric);
184
185 if (icmpv6->invflags & ~IP6T_ICMP_INV)
186 printf(" Unknown invflags: 0x%X",
187 icmpv6->invflags & ~IP6T_ICMP_INV);
188 }
189
icmp6_save(const void * ip,const struct xt_entry_match * match)190 static void icmp6_save(const void *ip, const struct xt_entry_match *match)
191 {
192 const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
193
194 if (icmpv6->invflags & IP6T_ICMP_INV)
195 printf(" !");
196
197 printf(" --icmpv6-type %u", icmpv6->type);
198 if (icmpv6->code[0] != 0 || icmpv6->code[1] != 0xFF)
199 printf("/%u", icmpv6->code[0]);
200 }
201
202 #define XT_ICMPV6_TYPE(type) (type - ND_ROUTER_SOLICIT)
203
204 static const char *icmp6_type_xlate_array[] = {
205 [XT_ICMPV6_TYPE(ND_ROUTER_SOLICIT)] = "nd-router-solicit",
206 [XT_ICMPV6_TYPE(ND_ROUTER_ADVERT)] = "nd-router-advert",
207 [XT_ICMPV6_TYPE(ND_NEIGHBOR_SOLICIT)] = "nd-neighbor-solicit",
208 [XT_ICMPV6_TYPE(ND_NEIGHBOR_ADVERT)] = "nd-neighbor-advert",
209 [XT_ICMPV6_TYPE(ND_REDIRECT)] = "nd-redirect",
210 };
211
icmp6_type_xlate(unsigned int type)212 static const char *icmp6_type_xlate(unsigned int type)
213 {
214 if (type < ND_ROUTER_SOLICIT || type > ND_REDIRECT)
215 return NULL;
216
217 return icmp6_type_xlate_array[XT_ICMPV6_TYPE(type)];
218 }
219
type_xlate_print(struct xt_xlate * xl,unsigned int icmptype,unsigned int code_min,unsigned int code_max)220 static unsigned int type_xlate_print(struct xt_xlate *xl, unsigned int icmptype,
221 unsigned int code_min,
222 unsigned int code_max)
223 {
224 unsigned int i;
225 const char *type_name;
226
227 if (code_min == code_max)
228 return 0;
229
230 type_name = icmp6_type_xlate(icmptype);
231
232 if (type_name) {
233 xt_xlate_add(xl, "%s", type_name);
234 } else {
235 for (i = 0; i < ARRAY_SIZE(icmpv6_codes); ++i)
236 if (icmpv6_codes[i].type == icmptype &&
237 icmpv6_codes[i].code_min == code_min &&
238 icmpv6_codes[i].code_max == code_max)
239 break;
240
241 if (i != ARRAY_SIZE(icmpv6_codes))
242 xt_xlate_add(xl, "%s", icmpv6_codes[i].name);
243 else
244 return 0;
245 }
246
247 return 1;
248 }
249
icmp6_xlate(struct xt_xlate * xl,const struct xt_xlate_mt_params * params)250 static int icmp6_xlate(struct xt_xlate *xl,
251 const struct xt_xlate_mt_params *params)
252 {
253 const struct ip6t_icmp *info = (struct ip6t_icmp *)params->match->data;
254
255 xt_xlate_add(xl, "icmpv6 type%s ",
256 (info->invflags & IP6T_ICMP_INV) ? " !=" : "");
257
258 if (!type_xlate_print(xl, info->type, info->code[0], info->code[1]))
259 return 0;
260
261 return 1;
262 }
263
264 static struct xtables_match icmp6_mt6_reg = {
265 .name = "icmp6",
266 .version = XTABLES_VERSION,
267 .family = NFPROTO_IPV6,
268 .size = XT_ALIGN(sizeof(struct ip6t_icmp)),
269 .userspacesize = XT_ALIGN(sizeof(struct ip6t_icmp)),
270 .help = icmp6_help,
271 .init = icmp6_init,
272 .print = icmp6_print,
273 .save = icmp6_save,
274 .x6_parse = icmp6_parse,
275 .x6_options = icmp6_opts,
276 .xlate = icmp6_xlate,
277 };
278
_init(void)279 void _init(void)
280 {
281 xtables_register_match(&icmp6_mt6_reg);
282 }
283