1 /* Shared library add-on to iptables for SCTP matching 2 * 3 * (C) 2003 by Harald Welte <laforge (at) 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 <stdbool.h> 11 #include <stdio.h> 12 #include <string.h> 13 #include <stdlib.h> 14 #include <getopt.h> 15 #include <netdb.h> 16 #include <ctype.h> 17 18 #include <netinet/in.h> 19 #include <xtables.h> 20 21 #include <linux/netfilter/xt_sctp.h> 22 23 #if 0 24 #define DEBUGP(format, first...) printf(format, ##first) 25 #define static 26 #else 27 #define DEBUGP(format, fist...) 28 #endif 29 30 static void 31 print_chunk(uint32_t chunknum, int numeric); 32 33 static void sctp_init(struct xt_entry_match *m) 34 { 35 int i; 36 struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data; 37 38 for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) { 39 einfo->flag_info[i].chunktype = -1; 40 } 41 } 42 43 static void sctp_help(void) 44 { 45 printf( 46 "sctp match options\n" 47 "[!] --source-port port[:port] match source port(s)\n" 48 " --sport ...\n" 49 "[!] --destination-port port[:port] match destination port(s)\n" 50 " --dport ...\n" 51 "[!] --chunk-types (all|any|none) (chunktype[:flags])+ match if all, any or none of\n" 52 " chunktypes are present\n" 53 "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 FORWARD_TSN ALL NONE\n"); 54 } 55 56 static const struct option sctp_opts[] = { 57 {.name = "source-port", .has_arg = true, .val = '1'}, 58 {.name = "sport", .has_arg = true, .val = '1'}, 59 {.name = "destination-port", .has_arg = true, .val = '2'}, 60 {.name = "dport", .has_arg = true, .val = '2'}, 61 {.name = "chunk-types", .has_arg = true, .val = '3'}, 62 XT_GETOPT_TABLEEND, 63 }; 64 65 static void 66 parse_sctp_ports(const char *portstring, 67 uint16_t *ports) 68 { 69 char *buffer; 70 char *cp; 71 72 buffer = strdup(portstring); 73 DEBUGP("%s\n", portstring); 74 if ((cp = strchr(buffer, ':')) == NULL) { 75 ports[0] = ports[1] = xtables_parse_port(buffer, "sctp"); 76 } 77 else { 78 *cp = '\0'; 79 cp++; 80 81 ports[0] = buffer[0] ? xtables_parse_port(buffer, "sctp") : 0; 82 ports[1] = cp[0] ? xtables_parse_port(cp, "sctp") : 0xFFFF; 83 84 if (ports[0] > ports[1]) 85 xtables_error(PARAMETER_PROBLEM, 86 "invalid portrange (min > max)"); 87 } 88 free(buffer); 89 } 90 91 struct sctp_chunk_names { 92 const char *name; 93 unsigned int chunk_type; 94 const char *valid_flags; 95 }; 96 97 /*'ALL' and 'NONE' will be treated specially. */ 98 static const struct sctp_chunk_names sctp_chunk_names[] 99 = { { .name = "DATA", .chunk_type = 0, .valid_flags = "----IUBE"}, 100 { .name = "INIT", .chunk_type = 1, .valid_flags = "--------"}, 101 { .name = "INIT_ACK", .chunk_type = 2, .valid_flags = "--------"}, 102 { .name = "SACK", .chunk_type = 3, .valid_flags = "--------"}, 103 { .name = "HEARTBEAT", .chunk_type = 4, .valid_flags = "--------"}, 104 { .name = "HEARTBEAT_ACK", .chunk_type = 5, .valid_flags = "--------"}, 105 { .name = "ABORT", .chunk_type = 6, .valid_flags = "-------T"}, 106 { .name = "SHUTDOWN", .chunk_type = 7, .valid_flags = "--------"}, 107 { .name = "SHUTDOWN_ACK", .chunk_type = 8, .valid_flags = "--------"}, 108 { .name = "ERROR", .chunk_type = 9, .valid_flags = "--------"}, 109 { .name = "COOKIE_ECHO", .chunk_type = 10, .valid_flags = "--------"}, 110 { .name = "COOKIE_ACK", .chunk_type = 11, .valid_flags = "--------"}, 111 { .name = "ECN_ECNE", .chunk_type = 12, .valid_flags = "--------"}, 112 { .name = "ECN_CWR", .chunk_type = 13, .valid_flags = "--------"}, 113 { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14, .valid_flags = "-------T"}, 114 { .name = "ASCONF", .chunk_type = 193, .valid_flags = "--------"}, 115 { .name = "ASCONF_ACK", .chunk_type = 128, .valid_flags = "--------"}, 116 { .name = "FORWARD_TSN", .chunk_type = 192, .valid_flags = "--------"}, 117 }; 118 119 static void 120 save_chunk_flag_info(struct xt_sctp_flag_info *flag_info, 121 int *flag_count, 122 int chunktype, 123 int bit, 124 int set) 125 { 126 int i; 127 128 for (i = 0; i < *flag_count; i++) { 129 if (flag_info[i].chunktype == chunktype) { 130 DEBUGP("Previous match found\n"); 131 flag_info[i].chunktype = chunktype; 132 flag_info[i].flag_mask |= (1 << bit); 133 if (set) { 134 flag_info[i].flag |= (1 << bit); 135 } 136 137 return; 138 } 139 } 140 141 if (*flag_count == XT_NUM_SCTP_FLAGS) { 142 xtables_error (PARAMETER_PROBLEM, 143 "Number of chunk types with flags exceeds currently allowed limit." 144 "Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and" 145 "recompiling both the kernel space and user space modules\n"); 146 } 147 148 flag_info[*flag_count].chunktype = chunktype; 149 flag_info[*flag_count].flag_mask |= (1 << bit); 150 if (set) { 151 flag_info[*flag_count].flag |= (1 << bit); 152 } 153 (*flag_count)++; 154 } 155 156 static void 157 parse_sctp_chunk(struct xt_sctp_info *einfo, 158 const char *chunks) 159 { 160 char *ptr; 161 char *buffer; 162 unsigned int i, j; 163 int found = 0; 164 char *chunk_flags; 165 166 buffer = strdup(chunks); 167 DEBUGP("Buffer: %s\n", buffer); 168 169 SCTP_CHUNKMAP_RESET(einfo->chunkmap); 170 171 if (!strcasecmp(buffer, "ALL")) { 172 SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap); 173 goto out; 174 } 175 176 if (!strcasecmp(buffer, "NONE")) { 177 SCTP_CHUNKMAP_RESET(einfo->chunkmap); 178 goto out; 179 } 180 181 for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) { 182 found = 0; 183 DEBUGP("Next Chunk type %s\n", ptr); 184 185 if ((chunk_flags = strchr(ptr, ':')) != NULL) { 186 *chunk_flags++ = 0; 187 } 188 189 for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i) 190 if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) { 191 DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type); 192 SCTP_CHUNKMAP_SET(einfo->chunkmap, 193 sctp_chunk_names[i].chunk_type); 194 found = 1; 195 break; 196 } 197 if (!found) 198 xtables_error(PARAMETER_PROBLEM, 199 "Unknown sctp chunk `%s'", ptr); 200 201 if (chunk_flags) { 202 DEBUGP("Chunk flags %s\n", chunk_flags); 203 for (j = 0; j < strlen(chunk_flags); j++) { 204 char *p; 205 int bit; 206 207 if ((p = strchr(sctp_chunk_names[i].valid_flags, 208 toupper(chunk_flags[j]))) != NULL) { 209 bit = p - sctp_chunk_names[i].valid_flags; 210 bit = 7 - bit; 211 212 save_chunk_flag_info(einfo->flag_info, 213 &(einfo->flag_count), i, bit, 214 isupper(chunk_flags[j])); 215 } else { 216 xtables_error(PARAMETER_PROBLEM, 217 "Invalid flags for chunk type %d\n", i); 218 } 219 } 220 } 221 } 222 out: 223 free(buffer); 224 } 225 226 static void 227 parse_sctp_chunks(struct xt_sctp_info *einfo, 228 const char *match_type, 229 const char *chunks) 230 { 231 DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks); 232 if (!strcasecmp(match_type, "ANY")) { 233 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY; 234 } else if (!strcasecmp(match_type, "ALL")) { 235 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL; 236 } else if (!strcasecmp(match_type, "ONLY")) { 237 einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY; 238 } else { 239 xtables_error (PARAMETER_PROBLEM, 240 "Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\""); 241 } 242 243 SCTP_CHUNKMAP_RESET(einfo->chunkmap); 244 parse_sctp_chunk(einfo, chunks); 245 } 246 247 static int 248 sctp_parse(int c, char **argv, int invert, unsigned int *flags, 249 const void *entry, struct xt_entry_match **match) 250 { 251 struct xt_sctp_info *einfo 252 = (struct xt_sctp_info *)(*match)->data; 253 254 switch (c) { 255 case '1': 256 if (*flags & XT_SCTP_SRC_PORTS) 257 xtables_error(PARAMETER_PROBLEM, 258 "Only one `--source-port' allowed"); 259 einfo->flags |= XT_SCTP_SRC_PORTS; 260 parse_sctp_ports(optarg, einfo->spts); 261 if (invert) 262 einfo->invflags |= XT_SCTP_SRC_PORTS; 263 *flags |= XT_SCTP_SRC_PORTS; 264 break; 265 266 case '2': 267 if (*flags & XT_SCTP_DEST_PORTS) 268 xtables_error(PARAMETER_PROBLEM, 269 "Only one `--destination-port' allowed"); 270 einfo->flags |= XT_SCTP_DEST_PORTS; 271 parse_sctp_ports(optarg, einfo->dpts); 272 if (invert) 273 einfo->invflags |= XT_SCTP_DEST_PORTS; 274 *flags |= XT_SCTP_DEST_PORTS; 275 break; 276 277 case '3': 278 if (*flags & XT_SCTP_CHUNK_TYPES) 279 xtables_error(PARAMETER_PROBLEM, 280 "Only one `--chunk-types' allowed"); 281 if (!argv[optind] 282 || argv[optind][0] == '-' || argv[optind][0] == '!') 283 xtables_error(PARAMETER_PROBLEM, 284 "--chunk-types requires two args"); 285 286 einfo->flags |= XT_SCTP_CHUNK_TYPES; 287 parse_sctp_chunks(einfo, optarg, argv[optind]); 288 if (invert) 289 einfo->invflags |= XT_SCTP_CHUNK_TYPES; 290 optind++; 291 *flags |= XT_SCTP_CHUNK_TYPES; 292 break; 293 } 294 return 1; 295 } 296 297 static const char * 298 port_to_service(int port) 299 { 300 const struct servent *service; 301 302 if ((service = getservbyport(htons(port), "sctp"))) 303 return service->s_name; 304 305 return NULL; 306 } 307 308 static void 309 print_port(uint16_t port, int numeric) 310 { 311 const char *service; 312 313 if (numeric || (service = port_to_service(port)) == NULL) 314 printf("%u", port); 315 else 316 printf("%s", service); 317 } 318 319 static void 320 print_ports(const char *name, uint16_t min, uint16_t max, 321 int invert, int numeric) 322 { 323 const char *inv = invert ? "!" : ""; 324 325 if (min != 0 || max != 0xFFFF || invert) { 326 printf(" %s", name); 327 if (min == max) { 328 printf(":%s", inv); 329 print_port(min, numeric); 330 } else { 331 printf("s:%s", inv); 332 print_port(min, numeric); 333 printf(":"); 334 print_port(max, numeric); 335 } 336 } 337 } 338 339 static void 340 print_chunk_flags(uint32_t chunknum, uint8_t chunk_flags, uint8_t chunk_flags_mask) 341 { 342 int i; 343 344 DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags, 345 chunk_flags_mask); 346 347 if (chunk_flags_mask) { 348 printf(":"); 349 } 350 351 for (i = 7; i >= 0; i--) { 352 if (chunk_flags_mask & (1 << i)) { 353 if (chunk_flags & (1 << i)) { 354 printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]); 355 } else { 356 printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i])); 357 } 358 } 359 } 360 } 361 362 static void 363 print_chunk(uint32_t chunknum, int numeric) 364 { 365 if (numeric) { 366 printf("0x%04X", chunknum); 367 } 368 else { 369 int i; 370 371 for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i) 372 if (sctp_chunk_names[i].chunk_type == chunknum) 373 printf("%s", sctp_chunk_names[chunknum].name); 374 } 375 } 376 377 static void 378 print_chunks(const struct xt_sctp_info *einfo, int numeric) 379 { 380 uint32_t chunk_match_type = einfo->chunk_match_type; 381 const struct xt_sctp_flag_info *flag_info = einfo->flag_info; 382 int flag_count = einfo->flag_count; 383 int i, j; 384 int flag; 385 386 switch (chunk_match_type) { 387 case SCTP_CHUNK_MATCH_ANY: printf(" any"); break; 388 case SCTP_CHUNK_MATCH_ALL: printf(" all"); break; 389 case SCTP_CHUNK_MATCH_ONLY: printf(" only"); break; 390 default: printf("Never reach here\n"); break; 391 } 392 393 if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) { 394 printf(" NONE"); 395 goto out; 396 } 397 398 if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) { 399 printf(" ALL"); 400 goto out; 401 } 402 403 flag = 0; 404 for (i = 0; i < 256; i++) { 405 if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) { 406 if (flag) 407 printf(","); 408 else 409 putchar(' '); 410 flag = 1; 411 print_chunk(i, numeric); 412 for (j = 0; j < flag_count; j++) { 413 if (flag_info[j].chunktype == i) { 414 print_chunk_flags(i, flag_info[j].flag, 415 flag_info[j].flag_mask); 416 } 417 } 418 } 419 } 420 out: 421 return; 422 } 423 424 static void 425 sctp_print(const void *ip, const struct xt_entry_match *match, int numeric) 426 { 427 const struct xt_sctp_info *einfo = 428 (const struct xt_sctp_info *)match->data; 429 430 printf(" sctp"); 431 432 if (einfo->flags & XT_SCTP_SRC_PORTS) { 433 print_ports("spt", einfo->spts[0], einfo->spts[1], 434 einfo->invflags & XT_SCTP_SRC_PORTS, 435 numeric); 436 } 437 438 if (einfo->flags & XT_SCTP_DEST_PORTS) { 439 print_ports("dpt", einfo->dpts[0], einfo->dpts[1], 440 einfo->invflags & XT_SCTP_DEST_PORTS, 441 numeric); 442 } 443 444 if (einfo->flags & XT_SCTP_CHUNK_TYPES) { 445 /* FIXME: print_chunks() is used in save() where the printing of '!' 446 s taken care of, so we need to do that here as well */ 447 if (einfo->invflags & XT_SCTP_CHUNK_TYPES) { 448 printf(" !"); 449 } 450 print_chunks(einfo, numeric); 451 } 452 } 453 454 static void sctp_save(const void *ip, const struct xt_entry_match *match) 455 { 456 const struct xt_sctp_info *einfo = 457 (const struct xt_sctp_info *)match->data; 458 459 if (einfo->flags & XT_SCTP_SRC_PORTS) { 460 if (einfo->invflags & XT_SCTP_SRC_PORTS) 461 printf(" !"); 462 if (einfo->spts[0] != einfo->spts[1]) 463 printf(" --sport %u:%u", 464 einfo->spts[0], einfo->spts[1]); 465 else 466 printf(" --sport %u", einfo->spts[0]); 467 } 468 469 if (einfo->flags & XT_SCTP_DEST_PORTS) { 470 if (einfo->invflags & XT_SCTP_DEST_PORTS) 471 printf(" !"); 472 if (einfo->dpts[0] != einfo->dpts[1]) 473 printf(" --dport %u:%u", 474 einfo->dpts[0], einfo->dpts[1]); 475 else 476 printf(" --dport %u", einfo->dpts[0]); 477 } 478 479 if (einfo->flags & XT_SCTP_CHUNK_TYPES) { 480 if (einfo->invflags & XT_SCTP_CHUNK_TYPES) 481 printf(" !"); 482 printf(" --chunk-types"); 483 484 print_chunks(einfo, 0); 485 } 486 } 487 488 static int sctp_xlate(struct xt_xlate *xl, 489 const struct xt_xlate_mt_params *params) 490 { 491 const struct xt_sctp_info *einfo = 492 (const struct xt_sctp_info *)params->match->data; 493 char *space = ""; 494 495 if (!einfo->flags) 496 return 0; 497 498 xt_xlate_add(xl, "sctp "); 499 500 if (einfo->flags & XT_SCTP_SRC_PORTS) { 501 if (einfo->spts[0] != einfo->spts[1]) 502 xt_xlate_add(xl, "sport%s %u-%u", 503 einfo->invflags & XT_SCTP_SRC_PORTS ? " !=" : "", 504 einfo->spts[0], einfo->spts[1]); 505 else 506 xt_xlate_add(xl, "sport%s %u", 507 einfo->invflags & XT_SCTP_SRC_PORTS ? " !=" : "", 508 einfo->spts[0]); 509 space = " "; 510 } 511 512 if (einfo->flags & XT_SCTP_DEST_PORTS) { 513 if (einfo->dpts[0] != einfo->dpts[1]) 514 xt_xlate_add(xl, "%sdport%s %u-%u", space, 515 einfo->invflags & XT_SCTP_DEST_PORTS ? " !=" : "", 516 einfo->dpts[0], einfo->dpts[1]); 517 else 518 xt_xlate_add(xl, "%sdport%s %u", space, 519 einfo->invflags & XT_SCTP_DEST_PORTS ? " !=" : "", 520 einfo->dpts[0]); 521 } 522 523 return 1; 524 } 525 526 static struct xtables_match sctp_match = { 527 .name = "sctp", 528 .family = NFPROTO_UNSPEC, 529 .version = XTABLES_VERSION, 530 .size = XT_ALIGN(sizeof(struct xt_sctp_info)), 531 .userspacesize = XT_ALIGN(sizeof(struct xt_sctp_info)), 532 .help = sctp_help, 533 .init = sctp_init, 534 .parse = sctp_parse, 535 .print = sctp_print, 536 .save = sctp_save, 537 .extra_opts = sctp_opts, 538 .xlate = sctp_xlate, 539 }; 540 541 void _init(void) 542 { 543 xtables_register_match(&sctp_match); 544 } 545
