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
  20 #ifndef ARRAY_SIZE
  21 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  22 #endif
  23
  24 #include <linux/netfilter_ipv4/ipt_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 ipt_entry_match *m,
  47      unsigned int *nfcache)
  48 {
  49         int i;
  50         struct ipt_sctp_info *einfo = (struct ipt_sctp_info *)m->data;
  51
  52         memset(einfo, 0, sizeof(struct ipt_sctp_info));
  53
  54         for (i = 0; i < IPT_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 int
  83 service_to_port(const char *name)
  84 {
  85         struct servent *service;
  86
  87         if ((service = getservbyname(name, "sctp")) != NULL)
  88                 return ntohs((unsigned short) service->s_port);
  89
  90         return -1;
  91 }
  92
  93 static u_int16_t
  94 parse_sctp_port(const char *port)
  95 {
  96         unsigned int portnum;
  97
  98         DEBUGP("%s\n", port);
  99         if (string_to_number(port, 0, 65535, &portnum) != -1 ||
 100             (portnum = service_to_port(port)) != -1)
 101                 return (u_int16_t)portnum;
 102
 103         exit_error(PARAMETER_PROBLEM,
 104                    "invalid SCTP port/service `%s' specified", port);
 105 }
 106
 107 static void
 108 parse_sctp_ports(const char *portstring,
 109                  u_int16_t *ports)
 110 {
 111         char *buffer;
 112         char *cp;
 113
 114         buffer = strdup(portstring);
 115         DEBUGP("%s\n", portstring);
 116         if ((cp = strchr(buffer, ':')) == NULL) {
 117                 ports[0] = ports[1] = parse_sctp_port(buffer);
 118         }
 119         else {
 120                 *cp = '\0';
 121                 cp++;
 122
 123                 ports[0] = buffer[0] ? parse_sctp_port(buffer) : 0;
 124                 ports[1] = cp[0] ? parse_sctp_port(cp) : 0xFFFF;
 125
 126                 if (ports[0] > ports[1])
 127                         exit_error(PARAMETER_PROBLEM,
 128                                    "invalid portrange (min > max)");
 129         }
 130         free(buffer);
 131 }
 132
 133 struct sctp_chunk_names {
 134         const char *name;
 135         unsigned int chunk_type;
 136         const char *valid_flags;
 137 };
 138
 139 /*'ALL' and 'NONE' will be treated specially. */
 140 static struct sctp_chunk_names sctp_chunk_names[]
 141 = { { .name = "DATA",           .chunk_type = 0,   .valid_flags = "-----UBE"},
 142     { .name = "INIT",           .chunk_type = 1,   .valid_flags = "--------"},
 143     { .name = "INIT_ACK",       .chunk_type = 2,   .valid_flags = "--------"},
 144     { .name = "SACK",           .chunk_type = 3,   .valid_flags = "--------"},
 145     { .name = "HEARTBEAT",      .chunk_type = 4,   .valid_flags = "--------"},
 146     { .name = "HEARTBEAT_ACK",  .chunk_type = 5,   .valid_flags = "--------"},
 147     { .name = "ABORT",          .chunk_type = 6,   .valid_flags = "-------T"},
 148     { .name = "SHUTDOWN",       .chunk_type = 7,   .valid_flags = "--------"},
 149     { .name = "SHUTDOWN_ACK",   .chunk_type = 8,   .valid_flags = "--------"},
 150     { .name = "ERROR",          .chunk_type = 9,   .valid_flags = "--------"},
 151     { .name = "COOKIE_ECHO",    .chunk_type = 10,  .valid_flags = "--------"},
 152     { .name = "COOKIE_ACK",     .chunk_type = 11,  .valid_flags = "--------"},
 153     { .name = "ECN_ECNE",       .chunk_type = 12,  .valid_flags = "--------"},
 154     { .name = "ECN_CWR",        .chunk_type = 13,  .valid_flags = "--------"},
 155     { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
 156     { .name = "ASCONF",         .chunk_type = 31,  .valid_flags = "--------"},
 157     { .name = "ASCONF_ACK",     .chunk_type = 30,  .valid_flags = "--------"},
 158 };
 159
 160 static void
 161 save_chunk_flag_info(struct ipt_sctp_flag_info *flag_info,
 162                      int *flag_count,
 163                      int chunktype,
 164                      int bit,
 165                      int set)
 166 {
 167         int i;
 168
 169         for (i = 0; i < *flag_count; i++) {
 170                 if (flag_info[i].chunktype == chunktype) {
 171                         DEBUGP("Previous match found\n");
 172                         flag_info[i].chunktype = chunktype;
 173                         flag_info[i].flag_mask |= (1 << bit);
 174                         if (set) {
 175                                 flag_info[i].flag |= (1 << bit);
 176                         }
 177
 178                         return;
 179                 }
 180         }
 181
 182         if (*flag_count == IPT_NUM_SCTP_FLAGS) {
 183                 exit_error (PARAMETER_PROBLEM,
 184                         "Number of chunk types with flags exceeds currently allowed limit."
 185                         "Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"
 186                         "recompiling both the kernel space and user space modules\n");
 187         }
 188
 189         flag_info[*flag_count].chunktype = chunktype;
 190         flag_info[*flag_count].flag_mask |= (1 << bit);
 191         if (set) {
 192                 flag_info[*flag_count].flag |= (1 << bit);
 193         }
 194         (*flag_count)++;
 195 }
 196
 197 static void
 198 parse_sctp_chunk(struct ipt_sctp_info *einfo,
 199                  const char *chunks)
 200 {
 201         char *ptr;
 202         char *buffer;
 203         unsigned int i, j;
 204         int found = 0;
 205         char *chunk_flags;
 206
 207         buffer = strdup(chunks);
 208         DEBUGP("Buffer: %s\n", buffer);
 209
 210         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 211
 212         if (!strcasecmp(buffer, "ALL")) {
 213                 SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
 214                 goto out;
 215         }
 216
 217         if (!strcasecmp(buffer, "NONE")) {
 218                 SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 219                 goto out;
 220         }
 221
 222         for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
 223                 found = 0;
 224                 DEBUGP("Next Chunk type %s\n", ptr);
 225
 226                 if ((chunk_flags = strchr(ptr, ':')) != NULL) {
 227                         *chunk_flags++ = 0;
 228                 }
 229
 230                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 231                         if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
 232                                 DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
 233                                 SCTP_CHUNKMAP_SET(einfo->chunkmap,
 234                                         sctp_chunk_names[i].chunk_type);
 235                                 found = 1;
 236                                 break;
 237                         }
 238                 }
 239                 if (!found)
 240                         exit_error(PARAMETER_PROBLEM,
 241                                    "Unknown sctp chunk `%s'", ptr);
 242
 243                 if (chunk_flags) {
 244                         DEBUGP("Chunk flags %s\n", chunk_flags);
 245                         for (j = 0; j < strlen(chunk_flags); j++) {
 246                                 char *p;
 247                                 int bit;
 248
 249                                 if ((p = strchr(sctp_chunk_names[i].valid_flags,
 250                                                 toupper(chunk_flags[j]))) != NULL) {
 251                                         bit = p - sctp_chunk_names[i].valid_flags;
 252                                         bit = 7 - bit;
 253
 254                                         save_chunk_flag_info(einfo->flag_info,
 255                                                 &(einfo->flag_count), i, bit,
 256                                                 isupper(chunk_flags[j]));
 257                                 } else {
 258                                         exit_error(PARAMETER_PROBLEM,
 259                                                 "Invalid flags for chunk type %d\n", i);
 260                                 }
 261                         }
 262                 }
 263         }
 264 out:
 265         free(buffer);
 266 }
 267
 268 static void
 269 parse_sctp_chunks(struct ipt_sctp_info *einfo,
 270                   const char *match_type,
 271                   const char *chunks)
 272 {
 273         DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
 274         if (!strcasecmp(match_type, "ANY")) {
 275                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
 276         } else  if (!strcasecmp(match_type, "ALL")) {
 277                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
 278         } else  if (!strcasecmp(match_type, "ONLY")) {
 279                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
 280         } else {
 281                 exit_error (PARAMETER_PROBLEM,
 282                         "Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
 283         }
 284
 285         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 286         parse_sctp_chunk(einfo, chunks);
 287 }
 288
 289 static int
 290 parse(int c, char **argv, int invert, unsigned int *flags,
 291       const struct ipt_entry *entry,
 292       unsigned int *nfcache,
 293       struct ipt_entry_match **match)
 294 {
 295         struct ipt_sctp_info *einfo
 296                 = (struct ipt_sctp_info *)(*match)->data;
 297
 298         switch (c) {
 299         case '1':
 300                 if (*flags & IPT_SCTP_SRC_PORTS)
 301                         exit_error(PARAMETER_PROBLEM,
 302                                    "Only one `--source-port' allowed");
 303                 einfo->flags |= IPT_SCTP_SRC_PORTS;
 304                 check_inverse(optarg, &invert, &optind, 0);
 305                 parse_sctp_ports(argv[optind-1], einfo->spts);
 306                 if (invert)
 307                         einfo->invflags |= IPT_SCTP_SRC_PORTS;
 308                 *flags |= IPT_SCTP_SRC_PORTS;
 309                 break;
 310
 311         case '2':
 312                 if (*flags & IPT_SCTP_DEST_PORTS)
 313                         exit_error(PARAMETER_PROBLEM,
 314                                    "Only one `--destination-port' allowed");
 315                 einfo->flags |= IPT_SCTP_DEST_PORTS;
 316                 check_inverse(optarg, &invert, &optind, 0);
 317                 parse_sctp_ports(argv[optind-1], einfo->dpts);
 318                 if (invert)
 319                         einfo->invflags |= IPT_SCTP_DEST_PORTS;
 320                 *flags |= IPT_SCTP_DEST_PORTS;
 321                 break;
 322
 323         case '3':
 324                 if (*flags & IPT_SCTP_CHUNK_TYPES)
 325                         exit_error(PARAMETER_PROBLEM,
 326                                    "Only one `--chunk-types' allowed");
 327                 check_inverse(optarg, &invert, &optind, 0);
 328
 329                 if (!argv[optind]
 330                     || argv[optind][0] == '-' || argv[optind][0] == '!')
 331                         exit_error(PARAMETER_PROBLEM,
 332                                    "--chunk-types requires two args");
 333
 334                 einfo->flags |= IPT_SCTP_CHUNK_TYPES;
 335                 parse_sctp_chunks(einfo, argv[optind-1], argv[optind]);
 336                 if (invert)
 337                         einfo->invflags |= IPT_SCTP_CHUNK_TYPES;
 338                 optind++;
 339                 *flags |= IPT_SCTP_CHUNK_TYPES;
 340                 break;
 341
 342         default:
 343                 return 0;
 344         }
 345         return 1;
 346 }
 347
 348 static void
 349 final_check(unsigned int flags)
 350 {
 351 }
 352
 353 static char *
 354 port_to_service(int port)
 355 {
 356         struct servent *service;
 357
 358         if ((service = getservbyport(htons(port), "sctp")))
 359                 return service->s_name;
 360
 361         return NULL;
 362 }
 363
 364 static void
 365 print_port(u_int16_t port, int numeric)
 366 {
 367         char *service;
 368
 369         if (numeric || (service = port_to_service(port)) == NULL)
 370                 printf("%u", port);
 371         else
 372                 printf("%s", service);
 373 }
 374
 375 static void
 376 print_ports(const char *name, u_int16_t min, u_int16_t max,
 377             int invert, int numeric)
 378 {
 379         const char *inv = invert ? "!" : "";
 380
 381         if (min != 0 || max != 0xFFFF || invert) {
 382                 printf("%s", name);
 383                 if (min == max) {
 384                         printf(":%s", inv);
 385                         print_port(min, numeric);
 386                 } else {
 387                         printf("s:%s", inv);
 388                         print_port(min, numeric);
 389                         printf(":");
 390                         print_port(max, numeric);
 391                 }
 392                 printf(" ");
 393         }
 394 }
 395
 396 static void
 397 print_chunk_flags(u_int32_t chunknum, u_int8_t chunk_flags, u_int8_t chunk_flags_mask)
 398 {
 399         int i;
 400
 401         DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
 402                         chunk_flags_mask);
 403
 404         if (chunk_flags_mask) {
 405                 printf(":");
 406         }
 407
 408         for (i = 7; i >= 0; i--) {
 409                 if (chunk_flags_mask & (1 << i)) {
 410                         if (chunk_flags & (1 << i)) {
 411                                 printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
 412                         } else {
 413                                 printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
 414                         }
 415                 }
 416         }
 417 }
 418
 419 static void
 420 print_chunk(u_int32_t chunknum, int numeric)
 421 {
 422         if (numeric) {
 423                 printf("0x%04X", chunknum);
 424         }
 425         else {
 426                 int i;
 427
 428                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 429                         if (sctp_chunk_names[i].chunk_type == chunknum)
 430                                 printf("%s", sctp_chunk_names[chunknum].name);
 431                 }
 432         }
 433 }
 434
 435 static void
 436 print_chunks(u_int32_t chunk_match_type,
 437              const u_int32_t *chunkmap,
 438              const struct ipt_sctp_flag_info *flag_info,
 439              int flag_count,
 440              int numeric)
 441 {
 442         int i, j;
 443         int flag;
 444
 445         switch (chunk_match_type) {
 446                 case SCTP_CHUNK_MATCH_ANY:      printf("any "); break;
 447                 case SCTP_CHUNK_MATCH_ALL:      printf("all "); break;
 448                 case SCTP_CHUNK_MATCH_ONLY:     printf("only "); break;
 449                 default:        printf("Never reach herer\n"); break;
 450         }
 451
 452         if (SCTP_CHUNKMAP_IS_CLEAR(chunkmap)) {
 453                 printf("NONE ");
 454                 goto out;
 455         }
 456
 457         if (SCTP_CHUNKMAP_IS_ALL_SET(chunkmap)) {
 458                 printf("ALL ");
 459                 goto out;
 460         }
 461
 462         flag = 0;
 463         for (i = 0; i < 256; i++) {
 464                 if (SCTP_CHUNKMAP_IS_SET(chunkmap, i)) {
 465                         flag && printf(",");
 466                         flag = 1;
 467                         print_chunk(i, numeric);
 468                         for (j = 0; j < flag_count; j++) {
 469                                 if (flag_info[j].chunktype == i) {
 470                                         print_chunk_flags(i, flag_info[j].flag,
 471                                                 flag_info[j].flag_mask);
 472                                 }
 473                         }
 474                 }
 475         }
 476
 477         flag && printf(" ");
 478 out:
 479         return;
 480 }
 481
 482 /* Prints out the matchinfo. */
 483 static void
 484 print(const struct ipt_ip *ip,
 485       const struct ipt_entry_match *match,
 486       int numeric)
 487 {
 488         const struct ipt_sctp_info *einfo =
 489                 (const struct ipt_sctp_info *)match->data;
 490
 491         printf("sctp ");
 492
 493         if (einfo->flags & IPT_SCTP_SRC_PORTS) {
 494                 print_ports("spt", einfo->spts[0], einfo->spts[1],
 495                         einfo->invflags & IPT_SCTP_SRC_PORTS,
 496                         numeric);
 497         }
 498
 499         if (einfo->flags & IPT_SCTP_DEST_PORTS) {
 500                 print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
 501                         einfo->invflags & IPT_SCTP_DEST_PORTS,
 502                         numeric);
 503         }
 504
 505         if (einfo->flags & IPT_SCTP_CHUNK_TYPES) {
 506                 /* FIXME: print_chunks() is used in save() where the printing of '!'
 507                 s taken care of, so we need to do that here as well */
 508                 if (einfo->invflags & IPT_SCTP_CHUNK_TYPES) {
 509                         printf("! ");
 510                 }
 511                 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
 512                         einfo->flag_info, einfo->flag_count, numeric);
 513         }
 514 }
 515
 516 /* Saves the union ipt_matchinfo in parsable form to stdout. */
 517 static void
 518 save(const struct ipt_ip *ip,
 519      const struct ipt_entry_match *match)
 520 {
 521         const struct ipt_sctp_info *einfo =
 522                 (const struct ipt_sctp_info *)match->data;
 523
 524         if (einfo->flags & IPT_SCTP_SRC_PORTS) {
 525                 if (einfo->invflags & IPT_SCTP_SRC_PORTS)
 526                         printf("! ");
 527                 if (einfo->spts[0] != einfo->spts[1])
 528                         printf("--sport %u:%u ",
 529                                einfo->spts[0], einfo->spts[1]);
 530                 else
 531                         printf("--sport %u ", einfo->spts[0]);
 532         }
 533
 534         if (einfo->flags & IPT_SCTP_DEST_PORTS) {
 535                 if (einfo->invflags & IPT_SCTP_DEST_PORTS)
 536                         printf("! ");
 537                 if (einfo->dpts[0] != einfo->dpts[1])
 538                         printf("--dport %u:%u ",
 539                                einfo->dpts[0], einfo->dpts[1]);
 540                 else
 541                         printf("--dport %u ", einfo->dpts[0]);
 542         }
 543
 544         if (einfo->flags & IPT_SCTP_CHUNK_TYPES) {
 545                 if (einfo->invflags & IPT_SCTP_CHUNK_TYPES)
 546                         printf("! ");
 547                 printf("--chunk-types ");
 548
 549                 print_chunks(einfo->chunk_match_type, einfo->chunkmap,
 550                         einfo->flag_info, einfo->flag_count, 0);
 551         }
 552 }
 553
 554 static
 555 struct iptables_match sctp
 556 = { .name          = "sctp",
 557     .version       = IPTABLES_VERSION,
 558     .size          = IPT_ALIGN(sizeof(struct ipt_sctp_info)),
 559     .userspacesize = IPT_ALIGN(sizeof(struct ipt_sctp_info)),
 560     .help          = &help,
 561     .init          = &init,
 562     .parse         = &parse,
 563     .final_check   = &final_check,
 564     .print         = &print,
 565     .save          = &save,
 566     .extra_opts    = opts
 567 };
 568
 569 void _init(void)
 570 {
 571         register_match(&sctp);
 572 }
 573