1 /* 2 * m_ipt.c iptables based targets 3 * utilities mostly ripped from iptables <duh, its the linux way> 4 * 5 * This program is free software; you can distribute it and/or 6 * modify it under the terms of the GNU General Public License 7 * as published by the Free Software Foundation; either version 8 * 2 of the License, or (at your option) any later version. 9 * 10 * Authors: J Hadi Salim (hadi (at) cyberus.ca) 11 */ 12 13 #include <syslog.h> 14 #include <sys/socket.h> 15 #include <netinet/in.h> 16 #include <arpa/inet.h> 17 #include <linux/if.h> 18 #include <iptables.h> 19 #include <linux/netfilter.h> 20 #include <linux/netfilter_ipv4/ip_tables.h> 21 #include "utils.h" 22 #include "tc_util.h" 23 #include <linux/tc_act/tc_ipt.h> 24 #include <stdio.h> 25 #include <dlfcn.h> 26 #include <getopt.h> 27 #include <errno.h> 28 #include <string.h> 29 #include <netdb.h> 30 #include <stdlib.h> 31 #include <ctype.h> 32 #include <stdarg.h> 33 #include <unistd.h> 34 #include <fcntl.h> 35 #include <sys/wait.h> 36 37 static const char *pname = "tc-ipt"; 38 static const char *tname = "mangle"; 39 static const char *pversion = "0.1"; 40 41 static const char *ipthooks[] = { 42 "NF_IP_PRE_ROUTING", 43 "NF_IP_LOCAL_IN", 44 "NF_IP_FORWARD", 45 "NF_IP_LOCAL_OUT", 46 "NF_IP_POST_ROUTING", 47 }; 48 49 static struct option original_opts[] = { 50 {"jump", 1, 0, 'j'}, 51 {0, 0, 0, 0} 52 }; 53 54 static struct iptables_target *t_list = NULL; 55 static struct option *opts = original_opts; 56 static unsigned int global_option_offset = 0; 57 #define OPTION_OFFSET 256 58 59 char *lib_dir; 60 61 void 62 register_target(struct iptables_target *me) 63 { 64 /* fprintf(stderr, "\nDummy register_target %s \n", me->name); 65 */ 66 me->next = t_list; 67 t_list = me; 68 69 } 70 71 void 72 xtables_register_target(struct iptables_target *me) 73 { 74 me->next = t_list; 75 t_list = me; 76 } 77 78 void 79 exit_tryhelp(int status) 80 { 81 fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n", 82 pname, pname); 83 exit(status); 84 } 85 86 void 87 exit_error(enum exittype status, char *msg, ...) 88 { 89 va_list args; 90 91 va_start(args, msg); 92 fprintf(stderr, "%s v%s: ", pname, pversion); 93 vfprintf(stderr, msg, args); 94 va_end(args); 95 fprintf(stderr, "\n"); 96 if (status == PARAMETER_PROBLEM) 97 exit_tryhelp(status); 98 if (status == VERSION_PROBLEM) 99 fprintf(stderr, 100 "Perhaps iptables or your kernel needs to be upgraded.\n"); 101 exit(status); 102 } 103 104 /* stolen from iptables 1.2.11 105 They should really have them as a library so i can link to them 106 Email them next time i remember 107 */ 108 109 char * 110 addr_to_dotted(const struct in_addr *addrp) 111 { 112 static char buf[20]; 113 const unsigned char *bytep; 114 115 bytep = (const unsigned char *) &(addrp->s_addr); 116 sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]); 117 return buf; 118 } 119 120 int string_to_number_ll(const char *s, unsigned long long min, 121 unsigned long long max, 122 unsigned long long *ret) 123 { 124 unsigned long long number; 125 char *end; 126 127 /* Handle hex, octal, etc. */ 128 errno = 0; 129 number = strtoull(s, &end, 0); 130 if (*end == '\0' && end != s) { 131 /* we parsed a number, let's see if we want this */ 132 if (errno != ERANGE && min <= number && (!max || number <= max)) { 133 *ret = number; 134 return 0; 135 } 136 } 137 return -1; 138 } 139 140 int string_to_number_l(const char *s, unsigned long min, unsigned long max, 141 unsigned long *ret) 142 { 143 int result; 144 unsigned long long number; 145 146 result = string_to_number_ll(s, min, max, &number); 147 *ret = (unsigned long)number; 148 149 return result; 150 } 151 152 int string_to_number(const char *s, unsigned int min, unsigned int max, 153 unsigned int *ret) 154 { 155 int result; 156 unsigned long number; 157 158 result = string_to_number_l(s, min, max, &number); 159 *ret = (unsigned int)number; 160 161 return result; 162 } 163 164 static void free_opts(struct option *local_opts) 165 { 166 if (local_opts != original_opts) { 167 free(local_opts); 168 opts = original_opts; 169 global_option_offset = 0; 170 } 171 } 172 173 static struct option * 174 merge_options(struct option *oldopts, const struct option *newopts, 175 unsigned int *option_offset) 176 { 177 struct option *merge; 178 unsigned int num_old, num_new, i; 179 180 for (num_old = 0; oldopts[num_old].name; num_old++) ; 181 for (num_new = 0; newopts[num_new].name; num_new++) ; 182 183 *option_offset = global_option_offset + OPTION_OFFSET; 184 185 merge = malloc(sizeof (struct option) * (num_new + num_old + 1)); 186 memcpy(merge, oldopts, num_old * sizeof (struct option)); 187 for (i = 0; i < num_new; i++) { 188 merge[num_old + i] = newopts[i]; 189 merge[num_old + i].val += *option_offset; 190 } 191 memset(merge + num_old + num_new, 0, sizeof (struct option)); 192 193 return merge; 194 } 195 196 static void * 197 fw_calloc(size_t count, size_t size) 198 { 199 void *p; 200 201 if ((p = (void *) calloc(count, size)) == NULL) { 202 perror("iptables: calloc failed"); 203 exit(1); 204 } 205 return p; 206 } 207 208 static struct iptables_target * 209 find_t(char *name) 210 { 211 struct iptables_target *m; 212 for (m = t_list; m; m = m->next) { 213 if (strcmp(m->name, name) == 0) 214 return m; 215 } 216 217 return NULL; 218 } 219 220 static struct iptables_target * 221 get_target_name(const char *name) 222 { 223 void *handle; 224 char *error; 225 char *new_name, *lname; 226 struct iptables_target *m; 227 char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)]; 228 229 #ifdef NO_SHARED_LIBS 230 return NULL; 231 #endif 232 233 new_name = malloc(strlen(name) + 1); 234 lname = malloc(strlen(name) + 1); 235 if (new_name) 236 memset(new_name, '\0', strlen(name) + 1); 237 else 238 exit_error(PARAMETER_PROBLEM, "get_target_name"); 239 240 if (lname) 241 memset(lname, '\0', strlen(name) + 1); 242 else 243 exit_error(PARAMETER_PROBLEM, "get_target_name"); 244 245 strcpy(new_name, name); 246 strcpy(lname, name); 247 248 if (isupper(lname[0])) { 249 int i; 250 for (i = 0; i < strlen(name); i++) { 251 lname[i] = tolower(lname[i]); 252 } 253 } 254 255 if (islower(new_name[0])) { 256 int i; 257 for (i = 0; i < strlen(new_name); i++) { 258 new_name[i] = toupper(new_name[i]); 259 } 260 } 261 262 /* try libxt_xx first */ 263 sprintf(path, "%s/libxt_%s.so", lib_dir, new_name); 264 handle = dlopen(path, RTLD_LAZY); 265 if (!handle) { 266 /* try libipt_xx next */ 267 sprintf(path, "%s/libipt_%s.so", lib_dir, new_name); 268 handle = dlopen(path, RTLD_LAZY); 269 270 if (!handle) { 271 sprintf(path, "%s/libxt_%s.so", lib_dir , lname); 272 handle = dlopen(path, RTLD_LAZY); 273 } 274 275 if (!handle) { 276 sprintf(path, "%s/libipt_%s.so", lib_dir , lname); 277 handle = dlopen(path, RTLD_LAZY); 278 } 279 /* ok, lets give up .. */ 280 if (!handle) { 281 fputs(dlerror(), stderr); 282 printf("\n"); 283 free(new_name); 284 return NULL; 285 } 286 } 287 288 m = dlsym(handle, new_name); 289 if ((error = dlerror()) != NULL) { 290 m = (struct iptables_target *) dlsym(handle, lname); 291 if ((error = dlerror()) != NULL) { 292 m = find_t(new_name); 293 if (NULL == m) { 294 m = find_t(lname); 295 if (NULL == m) { 296 fputs(error, stderr); 297 fprintf(stderr, "\n"); 298 dlclose(handle); 299 free(new_name); 300 return NULL; 301 } 302 } 303 } 304 } 305 306 free(new_name); 307 return m; 308 } 309 310 311 struct in_addr *dotted_to_addr(const char *dotted) 312 { 313 static struct in_addr addr; 314 unsigned char *addrp; 315 char *p, *q; 316 unsigned int onebyte; 317 int i; 318 char buf[20]; 319 320 /* copy dotted string, because we need to modify it */ 321 strncpy(buf, dotted, sizeof (buf) - 1); 322 addrp = (unsigned char *) &(addr.s_addr); 323 324 p = buf; 325 for (i = 0; i < 3; i++) { 326 if ((q = strchr(p, '.')) == NULL) 327 return (struct in_addr *) NULL; 328 329 *q = '\0'; 330 if (string_to_number(p, 0, 255, &onebyte) == -1) 331 return (struct in_addr *) NULL; 332 333 addrp[i] = (unsigned char) onebyte; 334 p = q + 1; 335 } 336 337 /* we've checked 3 bytes, now we check the last one */ 338 if (string_to_number(p, 0, 255, &onebyte) == -1) 339 return (struct in_addr *) NULL; 340 341 addrp[3] = (unsigned char) onebyte; 342 343 return &addr; 344 } 345 346 static void set_revision(char *name, u_int8_t revision) 347 { 348 /* Old kernel sources don't have ".revision" field, 349 * but we stole a byte from name. */ 350 name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0'; 351 name[IPT_FUNCTION_MAXNAMELEN - 1] = revision; 352 } 353 354 /* 355 * we may need to check for version mismatch 356 */ 357 int 358 build_st(struct iptables_target *target, struct ipt_entry_target *t) 359 { 360 unsigned int nfcache = 0; 361 362 if (target) { 363 size_t size; 364 365 size = 366 IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size; 367 368 if (NULL == t) { 369 target->t = fw_calloc(1, size); 370 target->t->u.target_size = size; 371 372 if (target->init != NULL) 373 target->init(target->t, &nfcache); 374 set_revision(target->t->u.user.name, target->revision); 375 } else { 376 target->t = t; 377 } 378 strcpy(target->t->u.user.name, target->name); 379 return 0; 380 } 381 382 return -1; 383 } 384 385 static int parse_ipt(struct action_util *a,int *argc_p, 386 char ***argv_p, int tca_id, struct nlmsghdr *n) 387 { 388 struct iptables_target *m = NULL; 389 struct ipt_entry fw; 390 struct rtattr *tail; 391 int c; 392 int rargc = *argc_p; 393 char **argv = *argv_p; 394 int argc = 0, iargc = 0; 395 char k[16]; 396 int res = -1; 397 int size = 0; 398 int iok = 0, ok = 0; 399 __u32 hook = 0, index = 0; 400 res = 0; 401 402 lib_dir = getenv("IPTABLES_LIB_DIR"); 403 if (!lib_dir) 404 lib_dir = IPT_LIB_DIR; 405 406 { 407 int i; 408 for (i = 0; i < rargc; i++) { 409 if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) { 410 break; 411 } 412 } 413 iargc = argc = i; 414 } 415 416 if (argc <= 2) { 417 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc); 418 return -1; 419 } 420 421 while (1) { 422 c = getopt_long(argc, argv, "j:", opts, NULL); 423 if (c == -1) 424 break; 425 switch (c) { 426 case 'j': 427 m = get_target_name(optarg); 428 if (NULL != m) { 429 430 if (0 > build_st(m, NULL)) { 431 printf(" %s error \n", m->name); 432 return -1; 433 } 434 opts = 435 merge_options(opts, m->extra_opts, 436 &m->option_offset); 437 } else { 438 fprintf(stderr," failed to find target %s\n\n", optarg); 439 return -1; 440 } 441 ok++; 442 break; 443 444 default: 445 memset(&fw, 0, sizeof (fw)); 446 if (m) { 447 m->parse(c - m->option_offset, argv, 0, 448 &m->tflags, NULL, &m->t); 449 } else { 450 fprintf(stderr," failed to find target %s\n\n", optarg); 451 return -1; 452 453 } 454 ok++; 455 break; 456 457 } 458 } 459 460 if (iargc > optind) { 461 if (matches(argv[optind], "index") == 0) { 462 if (get_u32(&index, argv[optind + 1], 10)) { 463 fprintf(stderr, "Illegal \"index\"\n"); 464 free_opts(opts); 465 return -1; 466 } 467 iok++; 468 469 optind += 2; 470 } 471 } 472 473 if (!ok && !iok) { 474 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv); 475 return -1; 476 } 477 478 /* check that we passed the correct parameters to the target */ 479 if (m) 480 m->final_check(m->tflags); 481 482 { 483 struct tcmsg *t = NLMSG_DATA(n); 484 if (t->tcm_parent != TC_H_ROOT 485 && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) { 486 hook = NF_IP_PRE_ROUTING; 487 } else { 488 hook = NF_IP_POST_ROUTING; 489 } 490 } 491 492 tail = NLMSG_TAIL(n); 493 addattr_l(n, MAX_MSG, tca_id, NULL, 0); 494 fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]); 495 fprintf(stdout, "\ttarget: "); 496 497 if (m) 498 m->print(NULL, m->t, 0); 499 fprintf(stdout, " index %d\n", index); 500 501 if (strlen(tname) > 16) { 502 size = 16; 503 k[15] = 0; 504 } else { 505 size = 1 + strlen(tname); 506 } 507 strncpy(k, tname, size); 508 509 addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size); 510 addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4); 511 addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4); 512 if (m) 513 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size); 514 tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail; 515 516 argc -= optind; 517 argv += optind; 518 *argc_p = rargc - iargc; 519 *argv_p = argv; 520 521 optind = 0; 522 free_opts(opts); 523 /* Clear flags if target will be used again */ 524 m->tflags=0; 525 m->used=0; 526 /* Free allocated memory */ 527 if (m->t) 528 free(m->t); 529 530 531 return 0; 532 533 } 534 535 static int 536 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg) 537 { 538 struct rtattr *tb[TCA_IPT_MAX + 1]; 539 struct ipt_entry_target *t = NULL; 540 541 if (arg == NULL) 542 return -1; 543 544 lib_dir = getenv("IPTABLES_LIB_DIR"); 545 if (!lib_dir) 546 lib_dir = IPT_LIB_DIR; 547 548 parse_rtattr_nested(tb, TCA_IPT_MAX, arg); 549 550 if (tb[TCA_IPT_TABLE] == NULL) { 551 fprintf(f, "[NULL ipt table name ] assuming mangle "); 552 } else { 553 fprintf(f, "tablename: %s ", 554 (char *) RTA_DATA(tb[TCA_IPT_TABLE])); 555 } 556 557 if (tb[TCA_IPT_HOOK] == NULL) { 558 fprintf(f, "[NULL ipt hook name ]\n "); 559 return -1; 560 } else { 561 __u32 hook; 562 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]); 563 fprintf(f, " hook: %s \n", ipthooks[hook]); 564 } 565 566 if (tb[TCA_IPT_TARG] == NULL) { 567 fprintf(f, "\t[NULL ipt target parameters ] \n"); 568 return -1; 569 } else { 570 struct iptables_target *m = NULL; 571 t = RTA_DATA(tb[TCA_IPT_TARG]); 572 m = get_target_name(t->u.user.name); 573 if (NULL != m) { 574 if (0 > build_st(m, t)) { 575 fprintf(stderr, " %s error \n", m->name); 576 return -1; 577 } 578 579 opts = 580 merge_options(opts, m->extra_opts, 581 &m->option_offset); 582 } else { 583 fprintf(stderr, " failed to find target %s\n\n", 584 t->u.user.name); 585 return -1; 586 } 587 fprintf(f, "\ttarget "); 588 m->print(NULL, m->t, 0); 589 if (tb[TCA_IPT_INDEX] == NULL) { 590 fprintf(f, " [NULL ipt target index ]\n"); 591 } else { 592 __u32 index; 593 index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]); 594 fprintf(f, " \n\tindex %d", index); 595 } 596 597 if (tb[TCA_IPT_CNT]) { 598 struct tc_cnt *c = RTA_DATA(tb[TCA_IPT_CNT]);; 599 fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt); 600 } 601 if (show_stats) { 602 if (tb[TCA_IPT_TM]) { 603 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]); 604 print_tm(f,tm); 605 } 606 } 607 fprintf(f, " \n"); 608 609 } 610 free_opts(opts); 611 612 return 0; 613 } 614 615 struct action_util ipt_action_util = { 616 .id = "ipt", 617 .parse_aopt = parse_ipt, 618 .print_aopt = print_ipt, 619 }; 620 621
