extensions/libip6t_icmp6.c

   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 enum {
  10         O_ICMPV6_TYPE = 0,
  11 };
  12
  13 struct icmpv6_names {
  14         const char *name;
  15         uint8_t type;
  16         uint8_t code_min, code_max;
  17 };
  18
  19 static const struct icmpv6_names icmpv6_codes[] = {
  20         { "destination-unreachable", 1, 0, 0xFF },
  21         {   "no-route", 1, 0, 0 },
  22         {   "communication-prohibited", 1, 1, 1 },
  23         {   "beyond-scope", 1, 2, 2 },
  24         {   "address-unreachable", 1, 3, 3 },
  25         {   "port-unreachable", 1, 4, 4 },
  26         {   "failed-policy", 1, 5, 5 },
  27         {   "reject-route", 1, 6, 6 },
  28
  29         { "packet-too-big", 2, 0, 0xFF },
  30
  31         { "time-exceeded", 3, 0, 0xFF },
  32         /* Alias */ { "ttl-exceeded", 3, 0, 0xFF },
  33         {   "ttl-zero-during-transit", 3, 0, 0 },
  34         {   "ttl-zero-during-reassembly", 3, 1, 1 },
  35
  36         { "parameter-problem", 4, 0, 0xFF },
  37         {   "bad-header", 4, 0, 0 },
  38         {   "unknown-header-type", 4, 1, 1 },
  39         {   "unknown-option", 4, 2, 2 },
  40
  41         { "echo-request", 128, 0, 0xFF },
  42         /* Alias */ { "ping", 128, 0, 0xFF },
  43
  44         { "echo-reply", 129, 0, 0xFF },
  45         /* Alias */ { "pong", 129, 0, 0xFF },
  46
  47         { "router-solicitation", 133, 0, 0xFF },
  48
  49         { "router-advertisement", 134, 0, 0xFF },
  50
  51         { "neighbour-solicitation", 135, 0, 0xFF },
  52         /* Alias */ { "neighbor-solicitation", 135, 0, 0xFF },
  53
  54         { "neighbour-advertisement", 136, 0, 0xFF },
  55         /* Alias */ { "neighbor-advertisement", 136, 0, 0xFF },
  56
  57         { "redirect", 137, 0, 0xFF },
  58
  59 };
  60
  61 static void
  62 print_icmpv6types(void)
  63 {
  64         unsigned int i;
  65         printf("Valid ICMPv6 Types:");
  66
  67         for (i = 0; i < ARRAY_SIZE(icmpv6_codes); ++i) {
  68                 if (i && icmpv6_codes[i].type == icmpv6_codes[i-1].type) {
  69                         if (icmpv6_codes[i].code_min == icmpv6_codes[i-1].code_min
  70                             && (icmpv6_codes[i].code_max
  71                                 == icmpv6_codes[i-1].code_max))
  72                                 printf(" (%s)", icmpv6_codes[i].name);
  73                         else
  74                                 printf("\n   %s", icmpv6_codes[i].name);
  75                 }
  76                 else
  77                         printf("\n%s", icmpv6_codes[i].name);
  78         }
  79         printf("\n");
  80 }
  81
  82 static void icmp6_help(void)
  83 {
  84         printf(
  85 "icmpv6 match options:\n"
  86 "[!] --icmpv6-type typename     match icmpv6 type\n"
  87 "                               (or numeric type or type/code)\n");
  88         print_icmpv6types();
  89 }
  90
  91 static const struct xt_option_entry icmp6_opts[] = {
  92         {.name = "icmpv6-type", .id = O_ICMPV6_TYPE, .type = XTTYPE_STRING,
  93          .flags = XTOPT_MAND | XTOPT_INVERT},
  94         XTOPT_TABLEEND,
  95 };
  96
  97 static void
  98 parse_icmpv6(const char *icmpv6type, uint8_t *type, uint8_t code[])
  99 {
 100         static const unsigned int limit = ARRAY_SIZE(icmpv6_codes);
 101         unsigned int match = limit;
 102         unsigned int i;
 103
 104         for (i = 0; i < limit; i++) {
 105                 if (strncasecmp(icmpv6_codes[i].name, icmpv6type, strlen(icmpv6type))
 106                     == 0) {
 107                         if (match != limit)
 108                                 xtables_error(PARAMETER_PROBLEM,
 109                                            "Ambiguous ICMPv6 type `%s':"
 110                                            " `%s' or `%s'?",
 111                                            icmpv6type,
 112                                            icmpv6_codes[match].name,
 113                                            icmpv6_codes[i].name);
 114                         match = i;
 115                 }
 116         }
 117
 118         if (match != limit) {
 119                 *type = icmpv6_codes[match].type;
 120                 code[0] = icmpv6_codes[match].code_min;
 121                 code[1] = icmpv6_codes[match].code_max;
 122         } else {
 123                 char *slash;
 124                 char buffer[strlen(icmpv6type) + 1];
 125                 unsigned int number;
 126
 127                 strcpy(buffer, icmpv6type);
 128                 slash = strchr(buffer, '/');
 129
 130                 if (slash)
 131                         *slash = '\0';
 132
 133                 if (!xtables_strtoui(buffer, NULL, &number, 0, UINT8_MAX))
 134                         xtables_error(PARAMETER_PROBLEM,
 135                                    "Invalid ICMPv6 type `%s'\n", buffer);
 136                 *type = number;
 137                 if (slash) {
 138                         if (!xtables_strtoui(slash+1, NULL, &number, 0, UINT8_MAX))
 139                                 xtables_error(PARAMETER_PROBLEM,
 140                                            "Invalid ICMPv6 code `%s'\n",
 141                                            slash+1);
 142                         code[0] = code[1] = number;
 143                 } else {
 144                         code[0] = 0;
 145                         code[1] = 0xFF;
 146                 }
 147         }
 148 }
 149
 150 static void icmp6_init(struct xt_entry_match *m)
 151 {
 152         struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)m->data;
 153
 154         icmpv6info->code[1] = 0xFF;
 155 }
 156
 157 static void icmp6_parse(struct xt_option_call *cb)
 158 {
 159         struct ip6t_icmp *icmpv6info = cb->data;
 160
 161         xtables_option_parse(cb);
 162         parse_icmpv6(cb->arg, &icmpv6info->type, icmpv6info->code);
 163         if (cb->invert)
 164                 icmpv6info->invflags |= IP6T_ICMP_INV;
 165 }
 166
 167 static void print_icmpv6type(uint8_t type,
 168                            uint8_t code_min, uint8_t code_max,
 169                            int invert,
 170                            int numeric)
 171 {
 172         if (!numeric) {
 173                 unsigned int i;
 174
 175                 for (i = 0; i < ARRAY_SIZE(icmpv6_codes); ++i)
 176                         if (icmpv6_codes[i].type == type
 177                             && icmpv6_codes[i].code_min == code_min
 178                             && icmpv6_codes[i].code_max == code_max)
 179                                 break;
 180
 181                 if (i != ARRAY_SIZE(icmpv6_codes)) {
 182                         printf(" %s%s",
 183                                invert ? "!" : "",
 184                                icmpv6_codes[i].name);
 185                         return;
 186                 }
 187         }
 188
 189         if (invert)
 190                 printf(" !");
 191
 192         printf("type %u", type);
 193         if (code_min == code_max)
 194                 printf(" code %u", code_min);
 195         else if (code_min != 0 || code_max != 0xFF)
 196                 printf(" codes %u-%u", code_min, code_max);
 197 }
 198
 199 static void icmp6_print(const void *ip, const struct xt_entry_match *match,
 200                         int numeric)
 201 {
 202         const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
 203
 204         printf(" ipv6-icmp");
 205         print_icmpv6type(icmpv6->type, icmpv6->code[0], icmpv6->code[1],
 206                        icmpv6->invflags & IP6T_ICMP_INV,
 207                        numeric);
 208
 209         if (icmpv6->invflags & ~IP6T_ICMP_INV)
 210                 printf(" Unknown invflags: 0x%X",
 211                        icmpv6->invflags & ~IP6T_ICMP_INV);
 212 }
 213
 214 static void icmp6_save(const void *ip, const struct xt_entry_match *match)
 215 {
 216         const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
 217
 218         if (icmpv6->invflags & IP6T_ICMP_INV)
 219                 printf(" !");
 220
 221         printf(" --icmpv6-type %u", icmpv6->type);
 222         if (icmpv6->code[0] != 0 || icmpv6->code[1] != 0xFF)
 223                 printf("/%u", icmpv6->code[0]);
 224 }
 225
 226 #define XT_ICMPV6_TYPE(type)    (type - ND_ROUTER_SOLICIT)
 227
 228 static const char *icmp6_type_xlate_array[] = {
 229         [XT_ICMPV6_TYPE(ND_ROUTER_SOLICIT)]     = "nd-router-solicit",
 230         [XT_ICMPV6_TYPE(ND_ROUTER_ADVERT)]      = "nd-router-advert",
 231         [XT_ICMPV6_TYPE(ND_NEIGHBOR_SOLICIT)]   = "nd-neighbor-solicit",
 232         [XT_ICMPV6_TYPE(ND_NEIGHBOR_ADVERT)]    = "nd-neighbor-advert",
 233         [XT_ICMPV6_TYPE(ND_REDIRECT)]           = "nd-redirect",
 234 };
 235
 236 static const char *icmp6_type_xlate(unsigned int type)
 237 {
 238         if (type < ND_ROUTER_SOLICIT || type > ND_REDIRECT)
 239                 return NULL;
 240
 241         return icmp6_type_xlate_array[XT_ICMPV6_TYPE(type)];
 242 }
 243
 244 static unsigned int type_xlate_print(struct xt_xlate *xl, unsigned int icmptype,
 245                                      unsigned int code_min,
 246                                      unsigned int code_max)
 247 {
 248         unsigned int i;
 249         const char *type_name;
 250
 251         if (code_min == code_max)
 252                 return 0;
 253
 254         type_name = icmp6_type_xlate(icmptype);
 255
 256         if (type_name) {
 257                 xt_xlate_add(xl, type_name);
 258         } else {
 259                 for (i = 0; i < ARRAY_SIZE(icmpv6_codes); ++i)
 260                         if (icmpv6_codes[i].type == icmptype &&
 261                             icmpv6_codes[i].code_min == code_min &&
 262                             icmpv6_codes[i].code_max == code_max)
 263                                 break;
 264
 265                 if (i != ARRAY_SIZE(icmpv6_codes))
 266                         xt_xlate_add(xl, icmpv6_codes[i].name);
 267                 else
 268                         return 0;
 269         }
 270
 271         return 1;
 272 }
 273
 274 static int icmp6_xlate(struct xt_xlate *xl,
 275                        const struct xt_xlate_mt_params *params)
 276 {
 277         const struct ip6t_icmp *info = (struct ip6t_icmp *)params->match->data;
 278
 279         xt_xlate_add(xl, "icmpv6 type%s ",
 280                      (info->invflags & IP6T_ICMP_INV) ? " !=" : "");
 281
 282         if (!type_xlate_print(xl, info->type, info->code[0], info->code[1]))
 283                 return 0;
 284
 285         xt_xlate_add(xl, " ");
 286
 287         return 1;
 288 }
 289
 290 static struct xtables_match icmp6_mt6_reg = {
 291         .name           = "icmp6",
 292         .version        = XTABLES_VERSION,
 293         .family         = NFPROTO_IPV6,
 294         .size           = XT_ALIGN(sizeof(struct ip6t_icmp)),
 295         .userspacesize  = XT_ALIGN(sizeof(struct ip6t_icmp)),
 296         .help           = icmp6_help,
 297         .init           = icmp6_init,
 298         .print          = icmp6_print,
 299         .save           = icmp6_save,
 300         .x6_parse       = icmp6_parse,
 301         .x6_options     = icmp6_opts,
 302         .xlate          = icmp6_xlate,
 303 };
 304
 305 void _init(void)
 306 {
 307         xtables_register_match(&icmp6_mt6_reg);
 308 }