extensions/libipt_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 <iptables.h>
  18 #include <linux/netfilter_ipv4/ip_tables.h>
  19 #include <linux/netfilter_ipv4/ipt_sctp.h>
  20
  21 #if 0
  22 #define DEBUGP(format, first...) printf(format, ##first)
  23 #define static
  24 #else
  25 #define DEBUGP(format, fist...)
  26 #endif
  27
  28 static void
  29 print_chunk(u_int32_t chunknum, int numeric);
  30
  31 /* Initialize the match. */
  32 static void
  33 init(struct ipt_entry_match *m,
  34      unsigned int *nfcache)
  35 {
  36         int i;
  37         struct ipt_sctp_info *einfo = (struct ipt_sctp_info *)m->data;
  38
  39         memset(einfo, 0, sizeof(struct ipt_sctp_info));
  40
  41         for (i = 0; i < IPT_NUM_SCTP_FLAGS; i++) {
  42                 einfo->flag_info[i].chunktype = -1;
  43         }
  44 }
  45
  46 static void help(void)
  47 {
  48         printf(
  49 "SCTP match v%s options\n"
  50 " --source-port [!] port[:port]                          match source port(s)\n"
  51 " --sport ...\n"
  52 " --destination-port [!] port[:port]                     match destination port(s)\n"
  53 " --dport ...\n"
  54 " --chunk-types [!] (all|any|none) (chunktype[:flags])+ match if all, any or none of\n"
  55 "                                                       chunktypes are present\n"
  56 "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",
  57         IPTABLES_VERSION);
  58 }
  59
  60 static struct option opts[] = {
  61         { .name = "source-port", .has_arg = 1, .flag = 0, .val = '1' },
  62         { .name = "sport", .has_arg = 1, .flag = 0, .val = '1' },
  63         { .name = "destination-port", .has_arg = 1, .flag = 0, .val = '2' },
  64         { .name = "dport", .has_arg = 1, .flag = 0, .val = '2' },
  65         { .name = "chunk-types", .has_arg = 1, .flag = 0, .val = '3' },
  66         { .name = 0 }
  67 };
  68
  69 static int
  70 service_to_port(const char *name)
  71 {
  72         struct servent *service;
  73
  74         if ((service = getservbyname(name, "sctp")) != NULL)
  75                 return ntohs((unsigned short) service->s_port);
  76
  77         return -1;
  78 }
  79
  80 static u_int16_t
  81 parse_sctp_port(const char *port)
  82 {
  83         unsigned int portnum;
  84
  85         DEBUGP("%s\n", port);
  86         if (string_to_number(port, 0, 65535, &portnum) != -1 ||
  87             (portnum = service_to_port(port)) != -1)
  88                 return (u_int16_t)portnum;
  89
  90         exit_error(PARAMETER_PROBLEM,
  91                    "invalid SCTP port/service `%s' specified", port);
  92 }
  93
  94 static void
  95 parse_sctp_ports(const char *portstring,
  96                  u_int16_t *ports)
  97 {
  98         char *buffer;
  99         char *cp;
 100
 101         buffer = strdup(portstring);
 102         DEBUGP("%s\n", portstring);
 103         if ((cp = strchr(buffer, ':')) == NULL) {
 104                 ports[0] = ports[1] = parse_sctp_port(buffer);
 105         }
 106         else {
 107                 *cp = '\0';
 108                 cp++;
 109
 110                 ports[0] = buffer[0] ? parse_sctp_port(buffer) : 0;
 111                 ports[1] = cp[0] ? parse_sctp_port(cp) : 0xFFFF;
 112
 113                 if (ports[0] > ports[1])
 114                         exit_error(PARAMETER_PROBLEM,
 115                                    "invalid portrange (min > max)");
 116         }
 117         free(buffer);
 118 }
 119
 120 struct sctp_chunk_names {
 121         const char *name;
 122         unsigned int chunk_type;
 123         const char *valid_flags;
 124 };
 125
 126 /*'ALL' and 'NONE' will be treated specially. */
 127 static struct sctp_chunk_names sctp_chunk_names[]
 128 = { { .name = "DATA",           .chunk_type = 0,   .valid_flags = "-----UBE"},
 129     { .name = "INIT",           .chunk_type = 1,   .valid_flags = "--------"},
 130     { .name = "INIT_ACK",       .chunk_type = 2,   .valid_flags = "--------"},
 131     { .name = "SACK",           .chunk_type = 3,   .valid_flags = "--------"},
 132     { .name = "HEARTBEAT",      .chunk_type = 4,   .valid_flags = "--------"},
 133     { .name = "HEARTBEAT_ACK",  .chunk_type = 5,   .valid_flags = "--------"},
 134     { .name = "ABORT",          .chunk_type = 6,   .valid_flags = "-------T"},
 135     { .name = "SHUTDOWN",       .chunk_type = 7,   .valid_flags = "--------"},
 136     { .name = "SHUTDOWN_ACK",   .chunk_type = 8,   .valid_flags = "--------"},
 137     { .name = "ERROR",          .chunk_type = 9,   .valid_flags = "--------"},
 138     { .name = "COOKIE_ECHO",    .chunk_type = 10,  .valid_flags = "--------"},
 139     { .name = "COOKIE_ACK",     .chunk_type = 11,  .valid_flags = "--------"},
 140     { .name = "ECN_ECNE",       .chunk_type = 12,  .valid_flags = "--------"},
 141     { .name = "ECN_CWR",        .chunk_type = 13,  .valid_flags = "--------"},
 142     { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
 143     { .name = "ASCONF",         .chunk_type = 31,  .valid_flags = "--------"},
 144     { .name = "ASCONF_ACK",     .chunk_type = 30,  .valid_flags = "--------"},
 145 };
 146
 147 static void
 148 save_chunk_flag_info(struct ipt_sctp_flag_info *flag_info,
 149                      int *flag_count,
 150                      int chunktype,
 151                      int bit,
 152                      int set)
 153 {
 154         int i;
 155
 156         for (i = 0; i < *flag_count; i++) {
 157                 if (flag_info[i].chunktype == chunktype) {
 158                         DEBUGP("Previous match found\n");
 159                         flag_info[i].chunktype = chunktype;
 160                         flag_info[i].flag_mask |= (1 << bit);
 161                         if (set) {
 162                                 flag_info[i].flag |= (1 << bit);
 163                         }
 164
 165                         return;
 166                 }
 167         }
 168
 169         if (*flag_count == IPT_NUM_SCTP_FLAGS) {
 170                 exit_error (PARAMETER_PROBLEM,
 171                         "Number of chunk types with flags exceeds currently allowed limit."
 172                         "Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"
 173                         "recompiling both the kernel space and user space modules\n");
 174         }
 175
 176         flag_info[*flag_count].chunktype = chunktype;
 177         flag_info[*flag_count].flag_mask |= (1 << bit);
 178         if (set) {
 179                 flag_info[*flag_count].flag |= (1 << bit);
 180         }
 181         (*flag_count)++;
 182 }
 183
 184 static void
 185 parse_sctp_chunk(struct ipt_sctp_info *einfo,
 186                  const char *chunks)
 187 {
 188         char *ptr;
 189         char *buffer;
 190         unsigned int i, j;
 191         int found = 0;
 192         char *chunk_flags;
 193
 194         buffer = strdup(chunks);
 195         DEBUGP("Buffer: %s\n", buffer);
 196
 197         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 198
 199         if (!strcasecmp(buffer, "ALL")) {
 200                 SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
 201                 goto out;
 202         }
 203
 204         if (!strcasecmp(buffer, "NONE")) {
 205                 SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 206                 goto out;
 207         }
 208
 209         for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
 210                 found = 0;
 211                 DEBUGP("Next Chunk type %s\n", ptr);
 212
 213                 if ((chunk_flags = strchr(ptr, ':')) != NULL) {
 214                         *chunk_flags++ = 0;
 215                 }
 216
 217                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 218                         if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
 219                                 DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
 220                                 SCTP_CHUNKMAP_SET(einfo->chunkmap,
 221                                         sctp_chunk_names[i].chunk_type);
 222                                 found = 1;
 223                                 break;
 224                         }
 225                 }
 226                 if (!found)
 227                         exit_error(PARAMETER_PROBLEM,
 228                                    "Unknown sctp chunk `%s'", ptr);
 229
 230                 if (chunk_flags) {
 231                         DEBUGP("Chunk flags %s\n", chunk_flags);
 232                         for (j = 0; j < strlen(chunk_flags); j++) {
 233                                 char *p;
 234                                 int bit;
 235
 236                                 if ((p = strchr(sctp_chunk_names[i].valid_flags,
 237                                                 toupper(chunk_flags[j]))) != NULL) {
 238                                         bit = p - sctp_chunk_names[i].valid_flags;
 239                                         bit = 7 - bit;
 240
 241                                         save_chunk_flag_info(einfo->flag_info,
 242                                                 &(einfo->flag_count), i, bit,
 243                                                 isupper(chunk_flags[j]));
 244                                 } else {
 245                                         exit_error(PARAMETER_PROBLEM,
 246                                                 "Invalid flags for chunk type %d\n", i);
 247                                 }
 248                         }
 249                 }
 250         }
 251 out:
 252         free(buffer);
 253 }
 254
 255 static void
 256 parse_sctp_chunks(struct ipt_sctp_info *einfo,
 257                   const char *match_type,
 258                   const char *chunks)
 259 {
 260         DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
 261         if (!strcasecmp(match_type, "ANY")) {
 262                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
 263         } else  if (!strcasecmp(match_type, "ALL")) {
 264                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
 265         } else  if (!strcasecmp(match_type, "ONLY")) {
 266                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
 267         } else {
 268                 exit_error (PARAMETER_PROBLEM,
 269                         "Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
 270         }
 271
 272         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 273         parse_sctp_chunk(einfo, chunks);
 274 }
 275
 276 static int
 277 parse(int c, char **argv, int invert, unsigned int *flags,
 278       const struct ipt_entry *entry,
 279       unsigned int *nfcache,
 280       struct ipt_entry_match **match)
 281 {
 282         struct ipt_sctp_info *einfo
 283                 = (struct ipt_sctp_info *)(*match)->data;
 284
 285         switch (c) {
 286         case '1':
 287                 if (*flags & IPT_SCTP_SRC_PORTS)
 288                         exit_error(PARAMETER_PROBLEM,
 289                                    "Only one `--source-port' allowed");
 290                 einfo->flags |= IPT_SCTP_SRC_PORTS;
 291                 check_inverse(optarg, &invert, &optind, 0);
 292                 parse_sctp_ports(argv[optind-1], einfo->spts);
 293                 if (invert)
 294                         einfo->invflags |= IPT_SCTP_SRC_PORTS;
 295                 *flags |= IPT_SCTP_SRC_PORTS;
 296                 break;
 297
 298         case '2':
 299                 if (*flags & IPT_SCTP_DEST_PORTS)
 300                         exit_error(PARAMETER_PROBLEM,
 301                                    "Only one `--destination-port' allowed");
 302                 einfo->flags |= IPT_SCTP_DEST_PORTS;
 303                 check_inverse(optarg, &invert, &optind, 0);
 304                 parse_sctp_ports(argv[optind-1], einfo->dpts);
 305                 if (invert)
 306                         einfo->invflags |= IPT_SCTP_DEST_PORTS;
 307                 *flags |= IPT_SCTP_DEST_PORTS;
 308                 break;
 309
 310         case '3':
 311                 if (*flags & IPT_SCTP_CHUNK_TYPES)
 312                         exit_error(PARAMETER_PROBLEM,
 313                                    "Only one `--chunk-types' allowed");
 314                 check_inverse(optarg, &invert, &optind, 0);
 315
 316                 if (!argv[optind]
 317                     || argv[optind][0] == '-' || argv[optind][0] == '!')
 318                         exit_error(PARAMETER_PROBLEM,
 319                                    "--chunk-types requires two args");
 320
 321                 einfo->flags |= IPT_SCTP_CHUNK_TYPES;
 322                 parse_sctp_chunks(einfo, argv[optind-1], argv[optind]);
 323                 if (invert)
 324                         einfo->invflags |= IPT_SCTP_CHUNK_TYPES;
 325                 optind++;
 326                 *flags |= IPT_SCTP_CHUNK_TYPES;
 327                 break;
 328
 329         default:
 330                 return 0;
 331         }
 332         return 1;
 333 }
 334
 335 static void
 336 final_check(unsigned int flags)
 337 {
 338 }
 339
 340 static char *
 341 port_to_service(int port)
 342 {
 343         struct servent *service;
 344
 345         if ((service = getservbyport(htons(port), "sctp")))
 346                 return service->s_name;
 347
 348         return NULL;
 349 }
 350
 351 static void
 352 print_port(u_int16_t port, int numeric)
 353 {
 354         char *service;
 355
 356         if (numeric || (service = port_to_service(port)) == NULL)
 357                 printf("%u", port);
 358         else
 359                 printf("%s", service);
 360 }
 361
 362 static void
 363 print_ports(const char *name, u_int16_t min, u_int16_t max,
 364             int invert, int numeric)
 365 {
 366         const char *inv = invert ? "!" : "";
 367
 368         if (min != 0 || max != 0xFFFF || invert) {
 369                 printf("%s", name);
 370                 if (min == max) {
 371                         printf(":%s", inv);
 372                         print_port(min, numeric);
 373                 } else {
 374                         printf("s:%s", inv);
 375                         print_port(min, numeric);
 376                         printf(":");
 377                         print_port(max, numeric);
 378                 }
 379                 printf(" ");
 380         }
 381 }
 382
 383 static void
 384 print_chunk_flags(u_int32_t chunknum, u_int8_t chunk_flags, u_int8_t chunk_flags_mask)
 385 {
 386         int i;
 387
 388         DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
 389                         chunk_flags_mask);
 390
 391         if (chunk_flags_mask) {
 392                 printf(":");
 393         }
 394
 395         for (i = 7; i >= 0; i--) {
 396                 if (chunk_flags_mask & (1 << i)) {
 397                         if (chunk_flags & (1 << i)) {
 398                                 printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
 399                         } else {
 400                                 printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
 401                         }
 402                 }
 403         }
 404 }
 405
 406 static void
 407 print_chunk(u_int32_t chunknum, int numeric)
 408 {
 409         if (numeric) {
 410                 printf("0x%04X", chunknum);
 411         }
 412         else {
 413                 int i;
 414
 415                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 416                         if (sctp_chunk_names[i].chunk_type == chunknum)
 417                                 printf("%s", sctp_chunk_names[chunknum].name);
 418                 }
 419         }
 420 }
 421
 422 static void
 423 print_chunks(u_int32_t chunk_match_type,
 424              const u_int32_t *chunkmap,
 425              const struct ipt_sctp_flag_info *flag_info,
 426              int flag_count,
 427              int numeric)
 428 {
 429         int i, j;
 430         int flag;
 431
 432         switch (chunk_match_type) {
 433                 case SCTP_CHUNK_MATCH_ANY:      printf("any "); break;
 434                 case SCTP_CHUNK_MATCH_ALL:      printf("all "); break;
 435                 case SCTP_CHUNK_MATCH_ONLY:     printf("only "); break;
 436                 default:        printf("Never reach herer\n"); break;
 437         }
 438
 439         if (SCTP_CHUNKMAP_IS_CLEAR(chunkmap)) {
 440                 printf("NONE ");
 441                 goto out;
 442         }
 443
 444         if (SCTP_CHUNKMAP_IS_ALL_SET(chunkmap)) {
 445                 printf("ALL ");
 446                 goto out;
 447         }
 448
 449         flag = 0;
 450         for (i = 0; i < 256; i++) {
 451                 if (SCTP_CHUNKMAP_IS_SET(chunkmap, i)) {
 452                         flag && printf(",");
 453                         flag = 1;
 454                         print_chunk(i, numeric);
 455                         for (j = 0; j < flag_count; j++) {
 456                                 if (flag_info[j].chunktype == i) {
 457                                         print_chunk_flags(i, flag_info[j].flag,
 458                                                 flag_info[j].flag_mask);
 459                                 }
 460                         }
 461                 }
 462         }
 463
 464         flag && printf(" ");
 465 out:
 466         return;
 467 }
 468
 469 /* Prints out the matchinfo. */
 470 static void
 471 print(const struct ipt_ip *ip,
 472       const struct ipt_entry_match *match,
 473       int numeric)
 474 {
 475         const struct ipt_sctp_info *einfo =
 476                 (const struct ipt_sctp_info *)match->data;
 477
 478         printf("sctp ");
 479
 480         if (einfo->flags & IPT_SCTP_SRC_PORTS) {
 481                 print_ports("spt", einfo->spts[0], einfo->spts[1],
 482                         einfo->invflags & IPT_SCTP_SRC_PORTS,
 483                         numeric);
 484         }
 485
 486         if (einfo->flags & IPT_SCTP_DEST_PORTS) {
 487                 print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
 488                         einfo->invflags & IPT_SCTP_DEST_PORTS,
 489                         numeric);
 490         }
 491
 492         if (einfo->flags & IPT_SCTP_CHUNK_TYPES) {
 493                 /* FIXME: print_chunks() is used in save() where the printing of '!'
 494                 s taken care of, so we need to do that here as well */
 495                 if (einfo->invflags & IPT_SCTP_CHUNK_TYPES) {
 496                         printf("! ");
 497                 }
 498                 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
 499                         einfo->flag_info, einfo->flag_count, numeric);
 500         }
 501 }
 502
 503 /* Saves the union ipt_matchinfo in parsable form to stdout. */
 504 static void
 505 save(const struct ipt_ip *ip,
 506      const struct ipt_entry_match *match)
 507 {
 508         const struct ipt_sctp_info *einfo =
 509                 (const struct ipt_sctp_info *)match->data;
 510
 511         if (einfo->flags & IPT_SCTP_SRC_PORTS) {
 512                 if (einfo->invflags & IPT_SCTP_SRC_PORTS)
 513                         printf("! ");
 514                 if (einfo->spts[0] != einfo->spts[1])
 515                         printf("--sport %u:%u ",
 516                                einfo->spts[0], einfo->spts[1]);
 517                 else
 518                         printf("--sport %u ", einfo->spts[0]);
 519         }
 520
 521         if (einfo->flags & IPT_SCTP_DEST_PORTS) {
 522                 if (einfo->invflags & IPT_SCTP_DEST_PORTS)
 523                         printf("! ");
 524                 if (einfo->dpts[0] != einfo->dpts[1])
 525                         printf("--dport %u:%u ",
 526                                einfo->dpts[0], einfo->dpts[1]);
 527                 else
 528                         printf("--dport %u ", einfo->dpts[0]);
 529         }
 530
 531         if (einfo->flags & IPT_SCTP_CHUNK_TYPES) {
 532                 if (einfo->invflags & IPT_SCTP_CHUNK_TYPES)
 533                         printf("! ");
 534                 printf("--chunk-types ");
 535
 536                 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
 537                         einfo->flag_info, einfo->flag_count, 0);
 538         }
 539 }
 540
 541 static
 542 struct iptables_match sctp
 543 = { .name          = "sctp",
 544     .version       = IPTABLES_VERSION,
 545     .size          = IPT_ALIGN(sizeof(struct ipt_sctp_info)),
 546     .userspacesize = IPT_ALIGN(sizeof(struct ipt_sctp_info)),
 547     .help          = &help,
 548     .init          = &init,
 549     .parse         = &parse,
 550     .final_check   = &final_check,
 551     .print         = &print,
 552     .save          = &save,
 553     .extra_opts    = opts
 554 };
 555
 556 void _init(void)
 557 {
 558         register_match(&sctp);
 559 }
 560