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 free(lname); 285 return NULL; 286 } 287 } 288 289 m = dlsym(handle, new_name); 290 if ((error = dlerror()) != NULL) { 291 m = (struct iptables_target *) dlsym(handle, lname); 292 if ((error = dlerror()) != NULL) { 293 m = find_t(new_name); 294 if (NULL == m) { 295 m = find_t(lname); 296 if (NULL == m) { 297 fputs(error, stderr); 298 fprintf(stderr, "\n"); 299 dlclose(handle); 300 free(new_name); 301 free(lname); 302 return NULL; 303 } 304 } 305 } 306 } 307 308 free(new_name); 309 free(lname); 310 return m; 311 } 312 313 314 struct in_addr *dotted_to_addr(const char *dotted) 315 { 316 static struct in_addr addr; 317 unsigned char *addrp; 318 char *p, *q; 319 unsigned int onebyte; 320 int i; 321 char buf[20]; 322 323 /* copy dotted string, because we need to modify it */ 324 strncpy(buf, dotted, sizeof (buf) - 1); 325 addrp = (unsigned char *) &(addr.s_addr); 326 327 p = buf; 328 for (i = 0; i < 3; i++) { 329 if ((q = strchr(p, '.')) == NULL) 330 return (struct in_addr *) NULL; 331 332 *q = '\0'; 333 if (string_to_number(p, 0, 255, &onebyte) == -1) 334 return (struct in_addr *) NULL; 335 336 addrp[i] = (unsigned char) onebyte; 337 p = q + 1; 338 } 339 340 /* we've checked 3 bytes, now we check the last one */ 341 if (string_to_number(p, 0, 255, &onebyte) == -1) 342 return (struct in_addr *) NULL; 343 344 addrp[3] = (unsigned char) onebyte; 345 346 return &addr; 347 } 348 349 static void set_revision(char *name, u_int8_t revision) 350 { 351 /* Old kernel sources don't have ".revision" field, 352 * but we stole a byte from name. */ 353 name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0'; 354 name[IPT_FUNCTION_MAXNAMELEN - 1] = revision; 355 } 356 357 /* 358 * we may need to check for version mismatch 359 */ 360 int 361 build_st(struct iptables_target *target, struct ipt_entry_target *t) 362 { 363 unsigned int nfcache = 0; 364 365 if (target) { 366 size_t size; 367 368 size = 369 IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size; 370 371 if (NULL == t) { 372 target->t = fw_calloc(1, size); 373 target->t->u.target_size = size; 374 375 if (target->init != NULL) 376 target->init(target->t, &nfcache); 377 set_revision(target->t->u.user.name, target->revision); 378 } else { 379 target->t = t; 380 } 381 strcpy(target->t->u.user.name, target->name); 382 return 0; 383 } 384 385 return -1; 386 } 387 388 static int parse_ipt(struct action_util *a,int *argc_p, 389 char ***argv_p, int tca_id, struct nlmsghdr *n) 390 { 391 struct iptables_target *m = NULL; 392 struct ipt_entry fw; 393 struct rtattr *tail; 394 int c; 395 int rargc = *argc_p; 396 char **argv = *argv_p; 397 int argc = 0, iargc = 0; 398 char k[16]; 399 int size = 0; 400 int iok = 0, ok = 0; 401 __u32 hook = 0, index = 0; 402 403 lib_dir = getenv("IPTABLES_LIB_DIR"); 404 if (!lib_dir) 405 lib_dir = IPT_LIB_DIR; 406 407 { 408 int i; 409 for (i = 0; i < rargc; i++) { 410 if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) { 411 break; 412 } 413 } 414 iargc = argc = i; 415 } 416 417 if (argc <= 2) { 418 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc); 419 return -1; 420 } 421 422 while (1) { 423 c = getopt_long(argc, argv, "j:", opts, NULL); 424 if (c == -1) 425 break; 426 switch (c) { 427 case 'j': 428 m = get_target_name(optarg); 429 if (NULL != m) { 430 431 if (0 > build_st(m, NULL)) { 432 printf(" %s error \n", m->name); 433 return -1; 434 } 435 opts = 436 merge_options(opts, m->extra_opts, 437 &m->option_offset); 438 } else { 439 fprintf(stderr," failed to find target %s\n\n", optarg); 440 return -1; 441 } 442 ok++; 443 break; 444 445 default: 446 memset(&fw, 0, sizeof (fw)); 447 if (m) { 448 m->parse(c - m->option_offset, argv, 0, 449 &m->tflags, NULL, &m->t); 450 } else { 451 fprintf(stderr," failed to find target %s\n\n", optarg); 452 return -1; 453 454 } 455 ok++; 456 break; 457 458 } 459 } 460 461 if (iargc > optind) { 462 if (matches(argv[optind], "index") == 0) { 463 if (get_u32(&index, argv[optind + 1], 10)) { 464 fprintf(stderr, "Illegal \"index\"\n"); 465 free_opts(opts); 466 return -1; 467 } 468 iok++; 469 470 optind += 2; 471 } 472 } 473 474 if (!ok && !iok) { 475 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv); 476 return -1; 477 } 478 479 /* check that we passed the correct parameters to the target */ 480 if (m) 481 m->final_check(m->tflags); 482 483 { 484 struct tcmsg *t = NLMSG_DATA(n); 485 if (t->tcm_parent != TC_H_ROOT 486 && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) { 487 hook = NF_IP_PRE_ROUTING; 488 } else { 489 hook = NF_IP_POST_ROUTING; 490 } 491 } 492 493 tail = NLMSG_TAIL(n); 494 addattr_l(n, MAX_MSG, tca_id, NULL, 0); 495 fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]); 496 fprintf(stdout, "\ttarget: "); 497 498 if (m) 499 m->print(NULL, m->t, 0); 500 fprintf(stdout, " index %d\n", index); 501 502 if (strlen(tname) > 16) { 503 size = 16; 504 k[15] = 0; 505 } else { 506 size = 1 + strlen(tname); 507 } 508 strncpy(k, tname, size); 509 510 addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size); 511 addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4); 512 addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4); 513 if (m) 514 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size); 515 tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail; 516 517 argc -= optind; 518 argv += optind; 519 *argc_p = rargc - iargc; 520 *argv_p = argv; 521 522 optind = 0; 523 free_opts(opts); 524 /* Clear flags if target will be used again */ 525 m->tflags=0; 526 m->used=0; 527 /* Free allocated memory */ 528 if (m->t) 529 free(m->t); 530 531 532 return 0; 533 534 } 535 536 static int 537 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg) 538 { 539 struct rtattr *tb[TCA_IPT_MAX + 1]; 540 struct ipt_entry_target *t = NULL; 541 542 if (arg == NULL) 543 return -1; 544 545 lib_dir = getenv("IPTABLES_LIB_DIR"); 546 if (!lib_dir) 547 lib_dir = IPT_LIB_DIR; 548 549 parse_rtattr_nested(tb, TCA_IPT_MAX, arg); 550 551 if (tb[TCA_IPT_TABLE] == NULL) { 552 fprintf(f, "[NULL ipt table name ] assuming mangle "); 553 } else { 554 fprintf(f, "tablename: %s ", 555 rta_getattr_str(tb[TCA_IPT_TABLE])); 556 } 557 558 if (tb[TCA_IPT_HOOK] == NULL) { 559 fprintf(f, "[NULL ipt hook name ]\n "); 560 return -1; 561 } else { 562 __u32 hook; 563 hook = rta_getattr_u32(tb[TCA_IPT_HOOK]); 564 fprintf(f, " hook: %s \n", ipthooks[hook]); 565 } 566 567 if (tb[TCA_IPT_TARG] == NULL) { 568 fprintf(f, "\t[NULL ipt target parameters ] \n"); 569 return -1; 570 } else { 571 struct iptables_target *m = NULL; 572 t = RTA_DATA(tb[TCA_IPT_TARG]); 573 m = get_target_name(t->u.user.name); 574 if (NULL != m) { 575 if (0 > build_st(m, t)) { 576 fprintf(stderr, " %s error \n", m->name); 577 return -1; 578 } 579 580 opts = 581 merge_options(opts, m->extra_opts, 582 &m->option_offset); 583 } else { 584 fprintf(stderr, " failed to find target %s\n\n", 585 t->u.user.name); 586 return -1; 587 } 588 fprintf(f, "\ttarget "); 589 m->print(NULL, m->t, 0); 590 if (tb[TCA_IPT_INDEX] == NULL) { 591 fprintf(f, " [NULL ipt target index ]\n"); 592 } else { 593 __u32 index; 594 index = rta_getattr_u32(tb[TCA_IPT_INDEX]); 595 fprintf(f, " \n\tindex %d", index); 596 } 597 598 if (tb[TCA_IPT_CNT]) { 599 struct tc_cnt *c = RTA_DATA(tb[TCA_IPT_CNT]);; 600 fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt); 601 } 602 if (show_stats) { 603 if (tb[TCA_IPT_TM]) { 604 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]); 605 print_tm(f,tm); 606 } 607 } 608 fprintf(f, " \n"); 609 610 } 611 free_opts(opts); 612 613 return 0; 614 } 615 616 struct action_util ipt_action_util = { 617 .id = "ipt", 618 .parse_aopt = parse_ipt, 619 .print_aopt = print_ipt, 620 }; 621 622
