extensions/libip6t_sctp.c

   1 /* Shared library add-on to iptables for SCTP matching
   2  *
   3  * (C) 2003 by Harald Welte <laforge@gnumonks.org>
   4  *
   5  * This program is distributed under the terms of GNU GPL v2, 1991
   6  *
   7  * libipt_ecn.c borrowed heavily from libipt_dscp.c
   8  *
   9  */
  10 #include <stdio.h>
  11 #include <string.h>
  12 #include <stdlib.h>
  13 #include <getopt.h>
  14 #include <netdb.h>
  15 #include <ctype.h>
  16
  17 #include <ip6tables.h>
  18 #include <linux/netfilter_ipv6/ip6_tables.h>
  19
  20 #ifndef ARRAY_SIZE
  21 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  22 #endif
  23
  24 #include <linux/netfilter/xt_sctp.h>
  25
  26 /* Some ZS!#@:$%*#$! has replaced the ELEMCOUNT macro in ipt_sctp.h with
  27  * ARRAY_SIZE without noticing that this file is used from userserspace,
  28  * and userspace doesn't have ARRAY_SIZE */
  29
  30 #ifndef ELEMCOUNT
  31 #define ELEMCOUNT ARRAY_SIZE
  32 #endif
  33
  34 #if 0
  35 #define DEBUGP(format, first...) printf(format, ##first)
  36 #define static
  37 #else
  38 #define DEBUGP(format, fist...)
  39 #endif
  40
  41 static void
  42 print_chunk(u_int32_t chunknum, int numeric);
  43
  44 /* Initialize the match. */
  45 static void
  46 init(struct ip6t_entry_match *m,
  47      unsigned int *nfcache)
  48 {
  49         int i;
  50         struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;
  51
  52         memset(einfo, 0, sizeof(struct xt_sctp_info));
  53
  54         for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
  55                 einfo->flag_info[i].chunktype = -1;
  56         }
  57 }
  58
  59 static void help(void)
  60 {
  61         printf(
  62 "SCTP match v%s options\n"
  63 " --source-port [!] port[:port]                          match source port(s)\n"
  64 " --sport ...\n"
  65 " --destination-port [!] port[:port]                     match destination port(s)\n"
  66 " --dport ...\n"
  67 " --chunk-types [!] (all|any|none) (chunktype[:flags])+ match if all, any or none of\n"
  68 "                                                       chunktypes are present\n"
  69 "chunktypes - DATA INIT INIT_ACK SACK HEARTBEAT HEARTBEAT_ACK ABORT SHUTDOWN SHUTDOWN_ACK ERROR COOKIE_ECHO COOKIE_ACK ECN_ECNE ECN_CWR SHUTDOWN_COMPLETE ASCONF ASCONF_ACK ALL NONE\n",
  70         IPTABLES_VERSION);
  71 }
  72
  73 static struct option opts[] = {
  74         { .name = "source-port", .has_arg = 1, .flag = 0, .val = '1' },
  75         { .name = "sport", .has_arg = 1, .flag = 0, .val = '1' },
  76         { .name = "destination-port", .has_arg = 1, .flag = 0, .val = '2' },
  77         { .name = "dport", .has_arg = 1, .flag = 0, .val = '2' },
  78         { .name = "chunk-types", .has_arg = 1, .flag = 0, .val = '3' },
  79         { .name = 0 }
  80 };
  81
  82 static void
  83 parse_sctp_ports(const char *portstring,
  84                  u_int16_t *ports)
  85 {
  86         char *buffer;
  87         char *cp;
  88
  89         buffer = strdup(portstring);
  90         DEBUGP("%s\n", portstring);
  91         if ((cp = strchr(buffer, ':')) == NULL) {
  92                 ports[0] = ports[1] = parse_port(buffer, "sctp");
  93         }
  94         else {
  95                 *cp = '\0';
  96                 cp++;
  97
  98                 ports[0] = buffer[0] ? parse_port(buffer, "sctp") : 0;
  99                 ports[1] = cp[0] ? parse_port(cp, "sctp") : 0xFFFF;
 100
 101                 if (ports[0] > ports[1])
 102                         exit_error(PARAMETER_PROBLEM,
 103                                    "invalid portrange (min > max)");
 104         }
 105         free(buffer);
 106 }
 107
 108 struct sctp_chunk_names {
 109         const char *name;
 110         unsigned int chunk_type;
 111         const char *valid_flags;
 112 };
 113
 114 /*'ALL' and 'NONE' will be treated specially. */
 115 static struct sctp_chunk_names sctp_chunk_names[]
 116 = { { .name = "DATA",           .chunk_type = 0,   .valid_flags = "-----UBE"},
 117     { .name = "INIT",           .chunk_type = 1,   .valid_flags = "--------"},
 118     { .name = "INIT_ACK",       .chunk_type = 2,   .valid_flags = "--------"},
 119     { .name = "SACK",           .chunk_type = 3,   .valid_flags = "--------"},
 120     { .name = "HEARTBEAT",      .chunk_type = 4,   .valid_flags = "--------"},
 121     { .name = "HEARTBEAT_ACK",  .chunk_type = 5,   .valid_flags = "--------"},
 122     { .name = "ABORT",          .chunk_type = 6,   .valid_flags = "-------T"},
 123     { .name = "SHUTDOWN",       .chunk_type = 7,   .valid_flags = "--------"},
 124     { .name = "SHUTDOWN_ACK",   .chunk_type = 8,   .valid_flags = "--------"},
 125     { .name = "ERROR",          .chunk_type = 9,   .valid_flags = "--------"},
 126     { .name = "COOKIE_ECHO",    .chunk_type = 10,  .valid_flags = "--------"},
 127     { .name = "COOKIE_ACK",     .chunk_type = 11,  .valid_flags = "--------"},
 128     { .name = "ECN_ECNE",       .chunk_type = 12,  .valid_flags = "--------"},
 129     { .name = "ECN_CWR",        .chunk_type = 13,  .valid_flags = "--------"},
 130     { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
 131     { .name = "ASCONF",         .chunk_type = 31,  .valid_flags = "--------"},
 132     { .name = "ASCONF_ACK",     .chunk_type = 30,  .valid_flags = "--------"},
 133 };
 134
 135 static void
 136 save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,
 137                      int *flag_count,
 138                      int chunktype,
 139                      int bit,
 140                      int set)
 141 {
 142         int i;
 143
 144         for (i = 0; i < *flag_count; i++) {
 145                 if (flag_info[i].chunktype == chunktype) {
 146                         DEBUGP("Previous match found\n");
 147                         flag_info[i].chunktype = chunktype;
 148                         flag_info[i].flag_mask |= (1 << bit);
 149                         if (set) {
 150                                 flag_info[i].flag |= (1 << bit);
 151                         }
 152
 153                         return;
 154                 }
 155         }
 156
 157         if (*flag_count == XT_NUM_SCTP_FLAGS) {
 158                 exit_error (PARAMETER_PROBLEM,
 159                         "Number of chunk types with flags exceeds currently allowed limit."
 160                         "Increasing this limit involves changing XT_NUM_SCTP_FLAGS and"
 161                         "recompiling both the kernel space and user space modules\n");
 162         }
 163
 164         flag_info[*flag_count].chunktype = chunktype;
 165         flag_info[*flag_count].flag_mask |= (1 << bit);
 166         if (set) {
 167                 flag_info[*flag_count].flag |= (1 << bit);
 168         }
 169         (*flag_count)++;
 170 }
 171
 172 static void
 173 parse_sctp_chunk(struct xt_sctp_info *einfo,
 174                  const char *chunks)
 175 {
 176         char *ptr;
 177         char *buffer;
 178         unsigned int i, j;
 179         int found = 0;
 180         char *chunk_flags;
 181
 182         buffer = strdup(chunks);
 183         DEBUGP("Buffer: %s\n", buffer);
 184
 185         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 186
 187         if (!strcasecmp(buffer, "ALL")) {
 188                 SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
 189                 goto out;
 190         }
 191
 192         if (!strcasecmp(buffer, "NONE")) {
 193                 SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 194                 goto out;
 195         }
 196
 197         for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
 198                 found = 0;
 199                 DEBUGP("Next Chunk type %s\n", ptr);
 200
 201                 if ((chunk_flags = strchr(ptr, ':')) != NULL) {
 202                         *chunk_flags++ = 0;
 203                 }
 204
 205                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 206                         if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
 207                                 DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
 208                                 SCTP_CHUNKMAP_SET(einfo->chunkmap,
 209                                         sctp_chunk_names[i].chunk_type);
 210                                 found = 1;
 211                                 break;
 212                         }
 213                 }
 214                 if (!found)
 215                         exit_error(PARAMETER_PROBLEM,
 216                                    "Unknown sctp chunk `%s'", ptr);
 217
 218                 if (chunk_flags) {
 219                         DEBUGP("Chunk flags %s\n", chunk_flags);
 220                         for (j = 0; j < strlen(chunk_flags); j++) {
 221                                 char *p;
 222                                 int bit;
 223
 224                                 if ((p = strchr(sctp_chunk_names[i].valid_flags,
 225                                                 toupper(chunk_flags[j]))) != NULL) {
 226                                         bit = p - sctp_chunk_names[i].valid_flags;
 227                                         bit = 7 - bit;
 228
 229                                         save_chunk_flag_info(einfo->flag_info,
 230                                                 &(einfo->flag_count), i, bit,
 231                                                 isupper(chunk_flags[j]));
 232                                 } else {
 233                                         exit_error(PARAMETER_PROBLEM,
 234                                                 "Invalid flags for chunk type %d\n", i);
 235                                 }
 236                         }
 237                 }
 238         }
 239 out:
 240         free(buffer);
 241 }
 242
 243 static void
 244 parse_sctp_chunks(struct xt_sctp_info *einfo,
 245                   const char *match_type,
 246                   const char *chunks)
 247 {
 248         DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
 249         if (!strcasecmp(match_type, "ANY")) {
 250                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
 251         } else  if (!strcasecmp(match_type, "ALL")) {
 252                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
 253         } else  if (!strcasecmp(match_type, "ONLY")) {
 254                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
 255         } else {
 256                 exit_error (PARAMETER_PROBLEM,
 257                         "Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
 258         }
 259
 260         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 261         parse_sctp_chunk(einfo, chunks);
 262 }
 263
 264 static int
 265 parse(int c, char **argv, int invert, unsigned int *flags,
 266       const struct ip6t_entry *entry,
 267       unsigned int *nfcache,
 268       struct ip6t_entry_match **match)
 269 {
 270         struct xt_sctp_info *einfo
 271                 = (struct xt_sctp_info *)(*match)->data;
 272
 273         switch (c) {
 274         case '1':
 275                 if (*flags & XT_SCTP_SRC_PORTS)
 276                         exit_error(PARAMETER_PROBLEM,
 277                                    "Only one `--source-port' allowed");
 278                 einfo->flags |= XT_SCTP_SRC_PORTS;
 279                 check_inverse(optarg, &invert, &optind, 0);
 280                 parse_sctp_ports(argv[optind-1], einfo->spts);
 281                 if (invert)
 282                         einfo->invflags |= XT_SCTP_SRC_PORTS;
 283                 *flags |= XT_SCTP_SRC_PORTS;
 284                 break;
 285
 286         case '2':
 287                 if (*flags & XT_SCTP_DEST_PORTS)
 288                         exit_error(PARAMETER_PROBLEM,
 289                                    "Only one `--destination-port' allowed");
 290                 einfo->flags |= XT_SCTP_DEST_PORTS;
 291                 check_inverse(optarg, &invert, &optind, 0);
 292                 parse_sctp_ports(argv[optind-1], einfo->dpts);
 293                 if (invert)
 294                         einfo->invflags |= XT_SCTP_DEST_PORTS;
 295                 *flags |= XT_SCTP_DEST_PORTS;
 296                 break;
 297
 298         case '3':
 299                 if (*flags & XT_SCTP_CHUNK_TYPES)
 300                         exit_error(PARAMETER_PROBLEM,
 301                                    "Only one `--chunk-types' allowed");
 302                 check_inverse(optarg, &invert, &optind, 0);
 303
 304                 if (!argv[optind]
 305                     || argv[optind][0] == '-' || argv[optind][0] == '!')
 306                         exit_error(PARAMETER_PROBLEM,
 307                                    "--chunk-types requires two args");
 308
 309                 einfo->flags |= XT_SCTP_CHUNK_TYPES;
 310                 parse_sctp_chunks(einfo, argv[optind-1], argv[optind]);
 311                 if (invert)
 312                         einfo->invflags |= XT_SCTP_CHUNK_TYPES;
 313                 optind++;
 314                 *flags |= XT_SCTP_CHUNK_TYPES;
 315                 break;
 316
 317         default:
 318                 return 0;
 319         }
 320         return 1;
 321 }
 322
 323 static void
 324 final_check(unsigned int flags)
 325 {
 326 }
 327
 328 static char *
 329 port_to_service(int port)
 330 {
 331         struct servent *service;
 332
 333         if ((service = getservbyport(htons(port), "sctp")))
 334                 return service->s_name;
 335
 336         return NULL;
 337 }
 338
 339 static void
 340 print_port(u_int16_t port, int numeric)
 341 {
 342         char *service;
 343
 344         if (numeric || (service = port_to_service(port)) == NULL)
 345                 printf("%u", port);
 346         else
 347                 printf("%s", service);
 348 }
 349
 350 static void
 351 print_ports(const char *name, u_int16_t min, u_int16_t max,
 352             int invert, int numeric)
 353 {
 354         const char *inv = invert ? "!" : "";
 355
 356         if (min != 0 || max != 0xFFFF || invert) {
 357                 printf("%s", name);
 358                 if (min == max) {
 359                         printf(":%s", inv);
 360                         print_port(min, numeric);
 361                 } else {
 362                         printf("s:%s", inv);
 363                         print_port(min, numeric);
 364                         printf(":");
 365                         print_port(max, numeric);
 366                 }
 367                 printf(" ");
 368         }
 369 }
 370
 371 static void
 372 print_chunk_flags(u_int32_t chunknum, u_int8_t chunk_flags, u_int8_t chunk_flags_mask)
 373 {
 374         int i;
 375
 376         DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
 377                         chunk_flags_mask);
 378
 379         if (chunk_flags_mask) {
 380                 printf(":");
 381         }
 382
 383         for (i = 7; i >= 0; i--) {
 384                 if (chunk_flags_mask & (1 << i)) {
 385                         if (chunk_flags & (1 << i)) {
 386                                 printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
 387                         } else {
 388                                 printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
 389                         }
 390                 }
 391         }
 392 }
 393
 394 static void
 395 print_chunk(u_int32_t chunknum, int numeric)
 396 {
 397         if (numeric) {
 398                 printf("0x%04X", chunknum);
 399         }
 400         else {
 401                 int i;
 402
 403                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 404                         if (sctp_chunk_names[i].chunk_type == chunknum)
 405                                 printf("%s", sctp_chunk_names[chunknum].name);
 406                 }
 407         }
 408 }
 409
 410 static void
 411 print_chunks(u_int32_t chunk_match_type,
 412              const u_int32_t *chunkmap,
 413              const struct xt_sctp_flag_info *flag_info,
 414              int flag_count,
 415              int numeric)
 416 {
 417         int i, j;
 418         int flag;
 419
 420         switch (chunk_match_type) {
 421                 case SCTP_CHUNK_MATCH_ANY:      printf("any "); break;
 422                 case SCTP_CHUNK_MATCH_ALL:      printf("all "); break;
 423                 case SCTP_CHUNK_MATCH_ONLY:     printf("only "); break;
 424                 default:        printf("Never reach herer\n"); break;
 425         }
 426
 427         if (SCTP_CHUNKMAP_IS_CLEAR(chunkmap)) {
 428                 printf("NONE ");
 429                 goto out;
 430         }
 431
 432         if (SCTP_CHUNKMAP_IS_ALL_SET(chunkmap)) {
 433                 printf("ALL ");
 434                 goto out;
 435         }
 436
 437         flag = 0;
 438         for (i = 0; i < 256; i++) {
 439                 if (SCTP_CHUNKMAP_IS_SET(chunkmap, i)) {
 440                         if (flag)
 441                                 printf(",");
 442                         flag = 1;
 443                         print_chunk(i, numeric);
 444                         for (j = 0; j < flag_count; j++) {
 445                                 if (flag_info[j].chunktype == i) {
 446                                         print_chunk_flags(i, flag_info[j].flag,
 447                                                 flag_info[j].flag_mask);
 448                                 }
 449                         }
 450                 }
 451         }
 452
 453         if (flag)
 454                 printf(" ");
 455 out:
 456         return;
 457 }
 458
 459 /* Prints out the matchinfo. */
 460 static void
 461 print(const struct ip6t_ip6 *ip,
 462       const struct ip6t_entry_match *match,
 463       int numeric)
 464 {
 465         const struct xt_sctp_info *einfo =
 466                 (const struct xt_sctp_info *)match->data;
 467
 468         printf("sctp ");
 469
 470         if (einfo->flags & XT_SCTP_SRC_PORTS) {
 471                 print_ports("spt", einfo->spts[0], einfo->spts[1],
 472                         einfo->invflags & XT_SCTP_SRC_PORTS,
 473                         numeric);
 474         }
 475
 476         if (einfo->flags & XT_SCTP_DEST_PORTS) {
 477                 print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
 478                         einfo->invflags & XT_SCTP_DEST_PORTS,
 479                         numeric);
 480         }
 481
 482         if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
 483                 /* FIXME: print_chunks() is used in save() where the printing of '!'
 484                 s taken care of, so we need to do that here as well */
 485                 if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
 486                         printf("! ");
 487                 }
 488                 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
 489                         einfo->flag_info, einfo->flag_count, numeric);
 490         }
 491 }
 492
 493 /* Saves the union xt_matchinfo in parsable form to stdout. */
 494 static void
 495 save(const struct ip6t_ip6 *ip,
 496      const struct ip6t_entry_match *match)
 497 {
 498         const struct xt_sctp_info *einfo =
 499                 (const struct xt_sctp_info *)match->data;
 500
 501         if (einfo->flags & XT_SCTP_SRC_PORTS) {
 502                 if (einfo->invflags & XT_SCTP_SRC_PORTS)
 503                         printf("! ");
 504                 if (einfo->spts[0] != einfo->spts[1])
 505                         printf("--sport %u:%u ",
 506                                einfo->spts[0], einfo->spts[1]);
 507                 else
 508                         printf("--sport %u ", einfo->spts[0]);
 509         }
 510
 511         if (einfo->flags & XT_SCTP_DEST_PORTS) {
 512                 if (einfo->invflags & XT_SCTP_DEST_PORTS)
 513                         printf("! ");
 514                 if (einfo->dpts[0] != einfo->dpts[1])
 515                         printf("--dport %u:%u ",
 516                                einfo->dpts[0], einfo->dpts[1]);
 517                 else
 518                         printf("--dport %u ", einfo->dpts[0]);
 519         }
 520
 521         if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
 522                 if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
 523                         printf("! ");
 524                 printf("--chunk-types ");
 525
 526                 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
 527                         einfo->flag_info, einfo->flag_count, 0);
 528         }
 529 }
 530
 531 static
 532 struct ip6tables_match sctp
 533 = { .name          = "sctp",
 534     .version       = IPTABLES_VERSION,
 535     .size          = IP6T_ALIGN(sizeof(struct xt_sctp_info)),
 536     .userspacesize = IP6T_ALIGN(sizeof(struct xt_sctp_info)),
 537     .help          = &help,
 538     .init          = &init,
 539     .parse         = &parse,
 540     .final_check   = &final_check,
 541     .print         = &print,
 542     .save          = &save,
 543     .extra_opts    = opts
 544 };
 545
 546 void _init(void)
 547 {
 548         register_match6(&sctp);
 549 }
 550