extensions/libxt_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 <xtables.h>
  18
  19 #ifndef ARRAY_SIZE
  20 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  21 #endif
  22
  23 #include <linux/netfilter/xt_sctp.h>
  24
  25 /* Some ZS!#@:$%*#$! has replaced the ELEMCOUNT macro in ipt_sctp.h with
  26  * ARRAY_SIZE without noticing that this file is used from userserspace,
  27  * and userspace doesn't have ARRAY_SIZE */
  28
  29 #ifndef ELEMCOUNT
  30 #define ELEMCOUNT ARRAY_SIZE
  31 #endif
  32
  33 #if 0
  34 #define DEBUGP(format, first...) printf(format, ##first)
  35 #define static
  36 #else
  37 #define DEBUGP(format, fist...)
  38 #endif
  39
  40 static void
  41 print_chunk(u_int32_t chunknum, int numeric);
  42
  43 /* Initialize the match. */
  44 static void sctp_init(struct xt_entry_match *m)
  45 {
  46         int i;
  47         struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;
  48
  49         memset(einfo, 0, sizeof(struct xt_sctp_info));
  50
  51         for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
  52                 einfo->flag_info[i].chunktype = -1;
  53         }
  54 }
  55
  56 static void sctp_help(void)
  57 {
  58         printf(
  59 "sctp match options\n"
  60 " --source-port [!] port[:port]                          match source port(s)\n"
  61 " --sport ...\n"
  62 " --destination-port [!] port[:port]                     match destination port(s)\n"
  63 " --dport ...\n"
  64 " --chunk-types [!] (all|any|none) (chunktype[:flags])+ match if all, any or none of\n"
  65 "                                                       chunktypes are present\n"
  66 "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");
  67 }
  68
  69 static const struct option sctp_opts[] = {
  70         { .name = "source-port", .has_arg = 1, .val = '1' },
  71         { .name = "sport", .has_arg = 1, .val = '1' },
  72         { .name = "destination-port", .has_arg = 1, .val = '2' },
  73         { .name = "dport", .has_arg = 1, .val = '2' },
  74         { .name = "chunk-types", .has_arg = 1, .val = '3' },
  75         { .name = NULL }
  76 };
  77
  78 static void
  79 parse_sctp_ports(const char *portstring,
  80                  u_int16_t *ports)
  81 {
  82         char *buffer;
  83         char *cp;
  84
  85         buffer = strdup(portstring);
  86         DEBUGP("%s\n", portstring);
  87         if ((cp = strchr(buffer, ':')) == NULL) {
  88                 ports[0] = ports[1] = parse_port(buffer, "sctp");
  89         }
  90         else {
  91                 *cp = '\0';
  92                 cp++;
  93
  94                 ports[0] = buffer[0] ? parse_port(buffer, "sctp") : 0;
  95                 ports[1] = cp[0] ? parse_port(cp, "sctp") : 0xFFFF;
  96
  97                 if (ports[0] > ports[1])
  98                         exit_error(PARAMETER_PROBLEM,
  99                                    "invalid portrange (min > max)");
 100         }
 101         free(buffer);
 102 }
 103
 104 struct sctp_chunk_names {
 105         const char *name;
 106         unsigned int chunk_type;
 107         const char *valid_flags;
 108 };
 109
 110 /*'ALL' and 'NONE' will be treated specially. */
 111 static const struct sctp_chunk_names sctp_chunk_names[]
 112 = { { .name = "DATA",           .chunk_type = 0,   .valid_flags = "-----UBE"},
 113     { .name = "INIT",           .chunk_type = 1,   .valid_flags = "--------"},
 114     { .name = "INIT_ACK",       .chunk_type = 2,   .valid_flags = "--------"},
 115     { .name = "SACK",           .chunk_type = 3,   .valid_flags = "--------"},
 116     { .name = "HEARTBEAT",      .chunk_type = 4,   .valid_flags = "--------"},
 117     { .name = "HEARTBEAT_ACK",  .chunk_type = 5,   .valid_flags = "--------"},
 118     { .name = "ABORT",          .chunk_type = 6,   .valid_flags = "-------T"},
 119     { .name = "SHUTDOWN",       .chunk_type = 7,   .valid_flags = "--------"},
 120     { .name = "SHUTDOWN_ACK",   .chunk_type = 8,   .valid_flags = "--------"},
 121     { .name = "ERROR",          .chunk_type = 9,   .valid_flags = "--------"},
 122     { .name = "COOKIE_ECHO",    .chunk_type = 10,  .valid_flags = "--------"},
 123     { .name = "COOKIE_ACK",     .chunk_type = 11,  .valid_flags = "--------"},
 124     { .name = "ECN_ECNE",       .chunk_type = 12,  .valid_flags = "--------"},
 125     { .name = "ECN_CWR",        .chunk_type = 13,  .valid_flags = "--------"},
 126     { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},
 127     { .name = "ASCONF",         .chunk_type = 193,  .valid_flags = "--------"},
 128     { .name = "ASCONF_ACK",     .chunk_type = 128,  .valid_flags = "--------"},
 129 };
 130
 131 static void
 132 save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,
 133                      int *flag_count,
 134                      int chunktype,
 135                      int bit,
 136                      int set)
 137 {
 138         int i;
 139
 140         for (i = 0; i < *flag_count; i++) {
 141                 if (flag_info[i].chunktype == chunktype) {
 142                         DEBUGP("Previous match found\n");
 143                         flag_info[i].chunktype = chunktype;
 144                         flag_info[i].flag_mask |= (1 << bit);
 145                         if (set) {
 146                                 flag_info[i].flag |= (1 << bit);
 147                         }
 148
 149                         return;
 150                 }
 151         }
 152
 153         if (*flag_count == XT_NUM_SCTP_FLAGS) {
 154                 exit_error (PARAMETER_PROBLEM,
 155                         "Number of chunk types with flags exceeds currently allowed limit."
 156                         "Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"
 157                         "recompiling both the kernel space and user space modules\n");
 158         }
 159
 160         flag_info[*flag_count].chunktype = chunktype;
 161         flag_info[*flag_count].flag_mask |= (1 << bit);
 162         if (set) {
 163                 flag_info[*flag_count].flag |= (1 << bit);
 164         }
 165         (*flag_count)++;
 166 }
 167
 168 static void
 169 parse_sctp_chunk(struct xt_sctp_info *einfo,
 170                  const char *chunks)
 171 {
 172         char *ptr;
 173         char *buffer;
 174         unsigned int i, j;
 175         int found = 0;
 176         char *chunk_flags;
 177
 178         buffer = strdup(chunks);
 179         DEBUGP("Buffer: %s\n", buffer);
 180
 181         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 182
 183         if (!strcasecmp(buffer, "ALL")) {
 184                 SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
 185                 goto out;
 186         }
 187
 188         if (!strcasecmp(buffer, "NONE")) {
 189                 SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 190                 goto out;
 191         }
 192
 193         for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
 194                 found = 0;
 195                 DEBUGP("Next Chunk type %s\n", ptr);
 196
 197                 if ((chunk_flags = strchr(ptr, ':')) != NULL) {
 198                         *chunk_flags++ = 0;
 199                 }
 200
 201                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 202                         if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
 203                                 DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
 204                                 SCTP_CHUNKMAP_SET(einfo->chunkmap,
 205                                         sctp_chunk_names[i].chunk_type);
 206                                 found = 1;
 207                                 break;
 208                         }
 209                 }
 210                 if (!found)
 211                         exit_error(PARAMETER_PROBLEM,
 212                                    "Unknown sctp chunk `%s'", ptr);
 213
 214                 if (chunk_flags) {
 215                         DEBUGP("Chunk flags %s\n", chunk_flags);
 216                         for (j = 0; j < strlen(chunk_flags); j++) {
 217                                 char *p;
 218                                 int bit;
 219
 220                                 if ((p = strchr(sctp_chunk_names[i].valid_flags,
 221                                                 toupper(chunk_flags[j]))) != NULL) {
 222                                         bit = p - sctp_chunk_names[i].valid_flags;
 223                                         bit = 7 - bit;
 224
 225                                         save_chunk_flag_info(einfo->flag_info,
 226                                                 &(einfo->flag_count), i, bit,
 227                                                 isupper(chunk_flags[j]));
 228                                 } else {
 229                                         exit_error(PARAMETER_PROBLEM,
 230                                                 "Invalid flags for chunk type %d\n", i);
 231                                 }
 232                         }
 233                 }
 234         }
 235 out:
 236         free(buffer);
 237 }
 238
 239 static void
 240 parse_sctp_chunks(struct xt_sctp_info *einfo,
 241                   const char *match_type,
 242                   const char *chunks)
 243 {
 244         DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
 245         if (!strcasecmp(match_type, "ANY")) {
 246                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
 247         } else  if (!strcasecmp(match_type, "ALL")) {
 248                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
 249         } else  if (!strcasecmp(match_type, "ONLY")) {
 250                 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
 251         } else {
 252                 exit_error (PARAMETER_PROBLEM,
 253                         "Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
 254         }
 255
 256         SCTP_CHUNKMAP_RESET(einfo->chunkmap);
 257         parse_sctp_chunk(einfo, chunks);
 258 }
 259
 260 static int
 261 sctp_parse(int c, char **argv, int invert, unsigned int *flags,
 262            const void *entry, struct xt_entry_match **match)
 263 {
 264         struct xt_sctp_info *einfo
 265                 = (struct xt_sctp_info *)(*match)->data;
 266
 267         switch (c) {
 268         case '1':
 269                 if (*flags & XT_SCTP_SRC_PORTS)
 270                         exit_error(PARAMETER_PROBLEM,
 271                                    "Only one `--source-port' allowed");
 272                 einfo->flags |= XT_SCTP_SRC_PORTS;
 273                 check_inverse(optarg, &invert, &optind, 0);
 274                 parse_sctp_ports(argv[optind-1], einfo->spts);
 275                 if (invert)
 276                         einfo->invflags |= XT_SCTP_SRC_PORTS;
 277                 *flags |= XT_SCTP_SRC_PORTS;
 278                 break;
 279
 280         case '2':
 281                 if (*flags & XT_SCTP_DEST_PORTS)
 282                         exit_error(PARAMETER_PROBLEM,
 283                                    "Only one `--destination-port' allowed");
 284                 einfo->flags |= XT_SCTP_DEST_PORTS;
 285                 check_inverse(optarg, &invert, &optind, 0);
 286                 parse_sctp_ports(argv[optind-1], einfo->dpts);
 287                 if (invert)
 288                         einfo->invflags |= XT_SCTP_DEST_PORTS;
 289                 *flags |= XT_SCTP_DEST_PORTS;
 290                 break;
 291
 292         case '3':
 293                 if (*flags & XT_SCTP_CHUNK_TYPES)
 294                         exit_error(PARAMETER_PROBLEM,
 295                                    "Only one `--chunk-types' allowed");
 296                 check_inverse(optarg, &invert, &optind, 0);
 297
 298                 if (!argv[optind]
 299                     || argv[optind][0] == '-' || argv[optind][0] == '!')
 300                         exit_error(PARAMETER_PROBLEM,
 301                                    "--chunk-types requires two args");
 302
 303                 einfo->flags |= XT_SCTP_CHUNK_TYPES;
 304                 parse_sctp_chunks(einfo, argv[optind-1], argv[optind]);
 305                 if (invert)
 306                         einfo->invflags |= XT_SCTP_CHUNK_TYPES;
 307                 optind++;
 308                 *flags |= XT_SCTP_CHUNK_TYPES;
 309                 break;
 310
 311         default:
 312                 return 0;
 313         }
 314         return 1;
 315 }
 316
 317 static char *
 318 port_to_service(int port)
 319 {
 320         struct servent *service;
 321
 322         if ((service = getservbyport(htons(port), "sctp")))
 323                 return service->s_name;
 324
 325         return NULL;
 326 }
 327
 328 static void
 329 print_port(u_int16_t port, int numeric)
 330 {
 331         char *service;
 332
 333         if (numeric || (service = port_to_service(port)) == NULL)
 334                 printf("%u", port);
 335         else
 336                 printf("%s", service);
 337 }
 338
 339 static void
 340 print_ports(const char *name, u_int16_t min, u_int16_t max,
 341             int invert, int numeric)
 342 {
 343         const char *inv = invert ? "!" : "";
 344
 345         if (min != 0 || max != 0xFFFF || invert) {
 346                 printf("%s", name);
 347                 if (min == max) {
 348                         printf(":%s", inv);
 349                         print_port(min, numeric);
 350                 } else {
 351                         printf("s:%s", inv);
 352                         print_port(min, numeric);
 353                         printf(":");
 354                         print_port(max, numeric);
 355                 }
 356                 printf(" ");
 357         }
 358 }
 359
 360 static void
 361 print_chunk_flags(u_int32_t chunknum, u_int8_t chunk_flags, u_int8_t chunk_flags_mask)
 362 {
 363         int i;
 364
 365         DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
 366                         chunk_flags_mask);
 367
 368         if (chunk_flags_mask) {
 369                 printf(":");
 370         }
 371
 372         for (i = 7; i >= 0; i--) {
 373                 if (chunk_flags_mask & (1 << i)) {
 374                         if (chunk_flags & (1 << i)) {
 375                                 printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
 376                         } else {
 377                                 printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
 378                         }
 379                 }
 380         }
 381 }
 382
 383 static void
 384 print_chunk(u_int32_t chunknum, int numeric)
 385 {
 386         if (numeric) {
 387                 printf("0x%04X", chunknum);
 388         }
 389         else {
 390                 int i;
 391
 392                 for (i = 0; i < ELEMCOUNT(sctp_chunk_names); i++) {
 393                         if (sctp_chunk_names[i].chunk_type == chunknum)
 394                                 printf("%s", sctp_chunk_names[chunknum].name);
 395                 }
 396         }
 397 }
 398
 399 static void
 400 print_chunks(const struct xt_sctp_info *einfo, int numeric)
 401 {
 402         u_int32_t chunk_match_type = einfo->chunk_match_type;
 403         const struct xt_sctp_flag_info *flag_info = einfo->flag_info;
 404         int flag_count = einfo->flag_count;
 405         int i, j;
 406         int flag;
 407
 408         switch (chunk_match_type) {
 409                 case SCTP_CHUNK_MATCH_ANY:      printf("any "); break;
 410                 case SCTP_CHUNK_MATCH_ALL:      printf("all "); break;
 411                 case SCTP_CHUNK_MATCH_ONLY:     printf("only "); break;
 412                 default:        printf("Never reach herer\n"); break;
 413         }
 414
 415         if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {
 416                 printf("NONE ");
 417                 goto out;
 418         }
 419
 420         if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {
 421                 printf("ALL ");
 422                 goto out;
 423         }
 424
 425         flag = 0;
 426         for (i = 0; i < 256; i++) {
 427                 if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {
 428                         if (flag)
 429                                 printf(",");
 430                         flag = 1;
 431                         print_chunk(i, numeric);
 432                         for (j = 0; j < flag_count; j++) {
 433                                 if (flag_info[j].chunktype == i) {
 434                                         print_chunk_flags(i, flag_info[j].flag,
 435                                                 flag_info[j].flag_mask);
 436                                 }
 437                         }
 438                 }
 439         }
 440
 441         if (flag)
 442                 printf(" ");
 443 out:
 444         return;
 445 }
 446
 447 /* Prints out the matchinfo. */
 448 static void
 449 sctp_print(const void *ip, const struct xt_entry_match *match, int numeric)
 450 {
 451         const struct xt_sctp_info *einfo =
 452                 (const struct xt_sctp_info *)match->data;
 453
 454         printf("sctp ");
 455
 456         if (einfo->flags & XT_SCTP_SRC_PORTS) {
 457                 print_ports("spt", einfo->spts[0], einfo->spts[1],
 458                         einfo->invflags & XT_SCTP_SRC_PORTS,
 459                         numeric);
 460         }
 461
 462         if (einfo->flags & XT_SCTP_DEST_PORTS) {
 463                 print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
 464                         einfo->invflags & XT_SCTP_DEST_PORTS,
 465                         numeric);
 466         }
 467
 468         if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
 469                 /* FIXME: print_chunks() is used in save() where the printing of '!'
 470                 s taken care of, so we need to do that here as well */
 471                 if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
 472                         printf("! ");
 473                 }
 474                 print_chunks(einfo, numeric);
 475         }
 476 }
 477
 478 /* Saves the union ipt_matchinfo in parsable form to stdout. */
 479 static void sctp_save(const void *ip, const struct xt_entry_match *match)
 480 {
 481         const struct xt_sctp_info *einfo =
 482                 (const struct xt_sctp_info *)match->data;
 483
 484         if (einfo->flags & XT_SCTP_SRC_PORTS) {
 485                 if (einfo->invflags & XT_SCTP_SRC_PORTS)
 486                         printf("! ");
 487                 if (einfo->spts[0] != einfo->spts[1])
 488                         printf("--sport %u:%u ",
 489                                einfo->spts[0], einfo->spts[1]);
 490                 else
 491                         printf("--sport %u ", einfo->spts[0]);
 492         }
 493
 494         if (einfo->flags & XT_SCTP_DEST_PORTS) {
 495                 if (einfo->invflags & XT_SCTP_DEST_PORTS)
 496                         printf("! ");
 497                 if (einfo->dpts[0] != einfo->dpts[1])
 498                         printf("--dport %u:%u ",
 499                                einfo->dpts[0], einfo->dpts[1]);
 500                 else
 501                         printf("--dport %u ", einfo->dpts[0]);
 502         }
 503
 504         if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
 505                 if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
 506                         printf("! ");
 507                 printf("--chunk-types ");
 508
 509                 print_chunks(einfo, 0);
 510         }
 511 }
 512
 513 static struct xtables_match sctp_match = {
 514         .name           = "sctp",
 515         .family         = AF_INET,
 516         .version        = XTABLES_VERSION,
 517         .size           = XT_ALIGN(sizeof(struct xt_sctp_info)),
 518         .userspacesize  = XT_ALIGN(sizeof(struct xt_sctp_info)),
 519         .help           = sctp_help,
 520         .init           = sctp_init,
 521         .parse          = sctp_parse,
 522         .print          = sctp_print,
 523         .save           = sctp_save,
 524         .extra_opts     = sctp_opts,
 525 };
 526
 527 static struct xtables_match sctp_match6 = {
 528         .name           = "sctp",
 529         .family         = AF_INET6,
 530         .version        = XTABLES_VERSION,
 531         .size           = XT_ALIGN(sizeof(struct xt_sctp_info)),
 532         .userspacesize  = XT_ALIGN(sizeof(struct xt_sctp_info)),
 533         .help           = sctp_help,
 534         .init           = sctp_init,
 535         .parse          = sctp_parse,
 536         .print          = sctp_print,
 537         .save           = sctp_save,
 538         .extra_opts     = sctp_opts,
 539 };
 540
 541 void _init(void)
 542 {
 543         xtables_register_match(&sctp_match);
 544         xtables_register_match(&sctp_match6);
 545 }
 546