libiptc.c revision 1a7732f965c2b09e526eeca8a551538fbdc099ef
1/* Library which manipulates firewall rules. Version $Revision$ */ 2 3/* Architecture of firewall rules is as follows: 4 * 5 * Chains go INPUT, FORWARD, OUTPUT then user chains. 6 * Each user chain starts with an ERROR node. 7 * Every chain ends with an unconditional jump: a RETURN for user chains, 8 * and a POLICY for built-ins. 9 */ 10 11/* (C) 1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See 12 * COPYING for details). 13 * (C) 2000-2004 by the Netfilter Core Team <coreteam@netfilter.org> 14 * 15 * 2003-Jun-20: Harald Welte <laforge@netfilter.org>: 16 * - Reimplementation of chain cache to use offsets instead of entries 17 * 2003-Jun-23: Harald Welte <laforge@netfilter.org>: 18 * - performance optimization, sponsored by Astaro AG (http://www.astaro.com/) 19 * don't rebuild the chain cache after every operation, instead fix it 20 * up after a ruleset change. 21 * 2004-Aug-18: Harald Welte <laforge@netfilter.org>: 22 * - further performance work: total reimplementation of libiptc. 23 * - libiptc now has a real internal (linked-list) represntation of the 24 * ruleset and a parser/compiler from/to this internal representation 25 * - again sponsored by Astaro AG (http://www.astaro.com/) 26 * 27 * 2008-Jan+Jul: Jesper Dangaard Brouer <hawk@comx.dk> 28 * - performance work: speedup chain list "name" searching. 29 * - performance work: speedup initial ruleset parsing. 30 * - sponsored by ComX Networks A/S (http://www.comx.dk/) 31 */ 32#include <sys/types.h> 33#include <sys/socket.h> 34#include <stdbool.h> 35#include <xtables.h> 36#include <libiptc/xtcshared.h> 37 38#include "linux_list.h" 39 40//#define IPTC_DEBUG2 1 41 42#ifdef IPTC_DEBUG2 43#include <fcntl.h> 44#define DEBUGP(x, args...) fprintf(stderr, "%s: " x, __FUNCTION__, ## args) 45#define DEBUGP_C(x, args...) fprintf(stderr, x, ## args) 46#else 47#define DEBUGP(x, args...) 48#define DEBUGP_C(x, args...) 49#endif 50 51#ifdef DEBUG 52#define debug(x, args...) fprintf(stderr, x, ## args) 53#else 54#define debug(x, args...) 55#endif 56 57static void *iptc_fn = NULL; 58 59static const char *hooknames[] = { 60 [HOOK_PRE_ROUTING] = "PREROUTING", 61 [HOOK_LOCAL_IN] = "INPUT", 62 [HOOK_FORWARD] = "FORWARD", 63 [HOOK_LOCAL_OUT] = "OUTPUT", 64 [HOOK_POST_ROUTING] = "POSTROUTING", 65}; 66 67/* Convenience structures */ 68struct chain_head; 69struct rule_head; 70 71struct counter_map 72{ 73 enum { 74 COUNTER_MAP_NOMAP, 75 COUNTER_MAP_NORMAL_MAP, 76 COUNTER_MAP_ZEROED, 77 COUNTER_MAP_SET 78 } maptype; 79 unsigned int mappos; 80}; 81 82enum iptcc_rule_type { 83 IPTCC_R_STANDARD, /* standard target (ACCEPT, ...) */ 84 IPTCC_R_MODULE, /* extension module (SNAT, ...) */ 85 IPTCC_R_FALLTHROUGH, /* fallthrough rule */ 86 IPTCC_R_JUMP, /* jump to other chain */ 87}; 88 89struct rule_head 90{ 91 struct list_head list; 92 struct chain_head *chain; 93 struct counter_map counter_map; 94 95 unsigned int index; /* index (needed for counter_map) */ 96 unsigned int offset; /* offset in rule blob */ 97 98 enum iptcc_rule_type type; 99 struct chain_head *jump; /* jump target, if IPTCC_R_JUMP */ 100 101 unsigned int size; /* size of entry data */ 102 STRUCT_ENTRY entry[0]; 103}; 104 105struct chain_head 106{ 107 struct list_head list; 108 char name[TABLE_MAXNAMELEN]; 109 unsigned int hooknum; /* hook number+1 if builtin */ 110 unsigned int references; /* how many jumps reference us */ 111 int verdict; /* verdict if builtin */ 112 113 STRUCT_COUNTERS counters; /* per-chain counters */ 114 struct counter_map counter_map; 115 116 unsigned int num_rules; /* number of rules in list */ 117 struct list_head rules; /* list of rules */ 118 119 unsigned int index; /* index (needed for jump resolval) */ 120 unsigned int head_offset; /* offset in rule blob */ 121 unsigned int foot_index; /* index (needed for counter_map) */ 122 unsigned int foot_offset; /* offset in rule blob */ 123}; 124 125struct xtc_handle { 126 int sockfd; 127 int changed; /* Have changes been made? */ 128 129 struct list_head chains; 130 131 struct chain_head *chain_iterator_cur; 132 struct rule_head *rule_iterator_cur; 133 134 unsigned int num_chains; /* number of user defined chains */ 135 136 struct chain_head **chain_index; /* array for fast chain list access*/ 137 unsigned int chain_index_sz;/* size of chain index array */ 138 139 int sorted_offsets; /* if chains are received sorted from kernel, 140 * then the offsets are also sorted. Says if its 141 * possible to bsearch offsets using chain_index. 142 */ 143 144 STRUCT_GETINFO info; 145 STRUCT_GET_ENTRIES *entries; 146}; 147 148enum bsearch_type { 149 BSEARCH_NAME, /* Binary search after chain name */ 150 BSEARCH_OFFSET, /* Binary search based on offset */ 151}; 152 153/* allocate a new chain head for the cache */ 154static struct chain_head *iptcc_alloc_chain_head(const char *name, int hooknum) 155{ 156 struct chain_head *c = malloc(sizeof(*c)); 157 if (!c) 158 return NULL; 159 memset(c, 0, sizeof(*c)); 160 161 strncpy(c->name, name, TABLE_MAXNAMELEN); 162 c->hooknum = hooknum; 163 INIT_LIST_HEAD(&c->rules); 164 165 return c; 166} 167 168/* allocate and initialize a new rule for the cache */ 169static struct rule_head *iptcc_alloc_rule(struct chain_head *c, unsigned int size) 170{ 171 struct rule_head *r = malloc(sizeof(*r)+size); 172 if (!r) 173 return NULL; 174 memset(r, 0, sizeof(*r)); 175 176 r->chain = c; 177 r->size = size; 178 179 return r; 180} 181 182/* notify us that the ruleset has been modified by the user */ 183static inline void 184set_changed(struct xtc_handle *h) 185{ 186 h->changed = 1; 187} 188 189#ifdef IPTC_DEBUG 190static void do_check(struct xtc_handle *h, unsigned int line); 191#define CHECK(h) do { if (!getenv("IPTC_NO_CHECK")) do_check((h), __LINE__); } while(0) 192#else 193#define CHECK(h) 194#endif 195 196 197/********************************************************************** 198 * iptc blob utility functions (iptcb_*) 199 **********************************************************************/ 200 201static inline int 202iptcb_get_number(const STRUCT_ENTRY *i, 203 const STRUCT_ENTRY *seek, 204 unsigned int *pos) 205{ 206 if (i == seek) 207 return 1; 208 (*pos)++; 209 return 0; 210} 211 212static inline int 213iptcb_get_entry_n(STRUCT_ENTRY *i, 214 unsigned int number, 215 unsigned int *pos, 216 STRUCT_ENTRY **pe) 217{ 218 if (*pos == number) { 219 *pe = i; 220 return 1; 221 } 222 (*pos)++; 223 return 0; 224} 225 226static inline STRUCT_ENTRY * 227iptcb_get_entry(struct xtc_handle *h, unsigned int offset) 228{ 229 return (STRUCT_ENTRY *)((char *)h->entries->entrytable + offset); 230} 231 232static unsigned int 233iptcb_entry2index(struct xtc_handle *const h, const STRUCT_ENTRY *seek) 234{ 235 unsigned int pos = 0; 236 237 if (ENTRY_ITERATE(h->entries->entrytable, h->entries->size, 238 iptcb_get_number, seek, &pos) == 0) { 239 fprintf(stderr, "ERROR: offset %u not an entry!\n", 240 (unsigned int)((char *)seek - (char *)h->entries->entrytable)); 241 abort(); 242 } 243 return pos; 244} 245 246static inline STRUCT_ENTRY * 247iptcb_offset2entry(struct xtc_handle *h, unsigned int offset) 248{ 249 return (STRUCT_ENTRY *) ((void *)h->entries->entrytable+offset); 250} 251 252 253static inline unsigned long 254iptcb_entry2offset(struct xtc_handle *const h, const STRUCT_ENTRY *e) 255{ 256 return (void *)e - (void *)h->entries->entrytable; 257} 258 259static inline unsigned int 260iptcb_offset2index(struct xtc_handle *const h, unsigned int offset) 261{ 262 return iptcb_entry2index(h, iptcb_offset2entry(h, offset)); 263} 264 265/* Returns 0 if not hook entry, else hooknumber + 1 */ 266static inline unsigned int 267iptcb_ent_is_hook_entry(STRUCT_ENTRY *e, struct xtc_handle *h) 268{ 269 unsigned int i; 270 271 for (i = 0; i < NUMHOOKS; i++) { 272 if ((h->info.valid_hooks & (1 << i)) 273 && iptcb_get_entry(h, h->info.hook_entry[i]) == e) 274 return i+1; 275 } 276 return 0; 277} 278 279 280/********************************************************************** 281 * Chain index (cache utility) functions 282 ********************************************************************** 283 * The chain index is an array with pointers into the chain list, with 284 * CHAIN_INDEX_BUCKET_LEN spacing. This facilitates the ability to 285 * speedup chain list searching, by find a more optimal starting 286 * points when searching the linked list. 287 * 288 * The starting point can be found fast by using a binary search of 289 * the chain index. Thus, reducing the previous search complexity of 290 * O(n) to O(log(n/k) + k) where k is CHAIN_INDEX_BUCKET_LEN. 291 * 292 * A nice property of the chain index, is that the "bucket" list 293 * length is max CHAIN_INDEX_BUCKET_LEN (when just build, inserts will 294 * change this). Oppose to hashing, where the "bucket" list length can 295 * vary a lot. 296 */ 297#ifndef CHAIN_INDEX_BUCKET_LEN 298#define CHAIN_INDEX_BUCKET_LEN 40 299#endif 300 301/* Another nice property of the chain index is that inserting/creating 302 * chains in chain list don't change the correctness of the chain 303 * index, it only causes longer lists in the buckets. 304 * 305 * To mitigate the performance penalty of longer bucket lists and the 306 * penalty of rebuilding, the chain index is rebuild only when 307 * CHAIN_INDEX_INSERT_MAX chains has been added. 308 */ 309#ifndef CHAIN_INDEX_INSERT_MAX 310#define CHAIN_INDEX_INSERT_MAX 355 311#endif 312 313static inline unsigned int iptcc_is_builtin(struct chain_head *c); 314 315/* Use binary search in the chain index array, to find a chain_head 316 * pointer closest to the place of the searched name element. 317 * 318 * Notes that, binary search (obviously) requires that the chain list 319 * is sorted by name. 320 * 321 * The not so obvious: The chain index array, is actually both sorted 322 * by name and offset, at the same time!. This is only true because, 323 * chain are stored sorted in the kernel (as we pushed it in sorted). 324 * 325 */ 326static struct list_head * 327__iptcc_bsearch_chain_index(const char *name, unsigned int offset, 328 unsigned int *idx, struct xtc_handle *handle, 329 enum bsearch_type type) 330{ 331 unsigned int pos, end; 332 int res; 333 334 struct list_head *list_pos; 335 list_pos=&handle->chains; 336 337 /* Check for empty array, e.g. no user defined chains */ 338 if (handle->chain_index_sz == 0) { 339 debug("WARNING: handle->chain_index_sz == 0\n"); 340 return list_pos; 341 } 342 343 /* Init */ 344 end = handle->chain_index_sz; 345 pos = end / 2; 346 347 debug("bsearch Find chain:%s (pos:%d end:%d) (offset:%d)\n", 348 name, pos, end, offset); 349 350 /* Loop */ 351 loop: 352 if (!handle->chain_index[pos]) { 353 fprintf(stderr, "ERROR: NULL pointer chain_index[%d]\n", pos); 354 return &handle->chains; /* Be safe, return orig start pos */ 355 } 356 357 debug("bsearch Index[%d] name:%s ", 358 pos, handle->chain_index[pos]->name); 359 360 /* Support for different compare functions */ 361 switch (type) { 362 case BSEARCH_NAME: 363 res = strcmp(name, handle->chain_index[pos]->name); 364 break; 365 case BSEARCH_OFFSET: 366 debug("head_offset:[%d] foot_offset:[%d] ", 367 handle->chain_index[pos]->head_offset, 368 handle->chain_index[pos]->foot_offset); 369 res = offset - handle->chain_index[pos]->head_offset; 370 break; 371 default: 372 fprintf(stderr, "ERROR: %d not a valid bsearch type\n", 373 type); 374 abort(); 375 break; 376 } 377 debug("res:%d ", res); 378 379 380 list_pos = &handle->chain_index[pos]->list; 381 *idx = pos; 382 383 if (res == 0) { /* Found element, by direct hit */ 384 debug("[found] Direct hit pos:%d end:%d\n", pos, end); 385 return list_pos; 386 } else if (res < 0) { /* Too far, jump back */ 387 end = pos; 388 pos = pos / 2; 389 390 /* Exit case: First element of array */ 391 if (end == 0) { 392 debug("[found] Reached first array elem (end%d)\n",end); 393 return list_pos; 394 } 395 debug("jump back to pos:%d (end:%d)\n", pos, end); 396 goto loop; 397 } else { /* res > 0; Not far enough, jump forward */ 398 399 /* Exit case: Last element of array */ 400 if (pos == handle->chain_index_sz-1) { 401 debug("[found] Last array elem (end:%d)\n", end); 402 return list_pos; 403 } 404 405 /* Exit case: Next index less, thus elem in this list section */ 406 switch (type) { 407 case BSEARCH_NAME: 408 res = strcmp(name, handle->chain_index[pos+1]->name); 409 break; 410 case BSEARCH_OFFSET: 411 res = offset - handle->chain_index[pos+1]->head_offset; 412 break; 413 } 414 415 if (res < 0) { 416 debug("[found] closest list (end:%d)\n", end); 417 return list_pos; 418 } 419 420 pos = (pos+end)/2; 421 debug("jump forward to pos:%d (end:%d)\n", pos, end); 422 goto loop; 423 } 424} 425 426/* Wrapper for string chain name based bsearch */ 427static struct list_head * 428iptcc_bsearch_chain_index(const char *name, unsigned int *idx, 429 struct xtc_handle *handle) 430{ 431 return __iptcc_bsearch_chain_index(name, 0, idx, handle, BSEARCH_NAME); 432} 433 434 435/* Wrapper for offset chain based bsearch */ 436static struct list_head * 437iptcc_bsearch_chain_offset(unsigned int offset, unsigned int *idx, 438 struct xtc_handle *handle) 439{ 440 struct list_head *pos; 441 442 /* If chains were not received sorted from kernel, then the 443 * offset bsearch is not possible. 444 */ 445 if (!handle->sorted_offsets) 446 pos = handle->chains.next; 447 else 448 pos = __iptcc_bsearch_chain_index(NULL, offset, idx, handle, 449 BSEARCH_OFFSET); 450 return pos; 451} 452 453 454#ifdef DEBUG 455/* Trivial linear search of chain index. Function used for verifying 456 the output of bsearch function */ 457static struct list_head * 458iptcc_linearly_search_chain_index(const char *name, struct xtc_handle *handle) 459{ 460 unsigned int i=0; 461 int res=0; 462 463 struct list_head *list_pos; 464 list_pos = &handle->chains; 465 466 if (handle->chain_index_sz) 467 list_pos = &handle->chain_index[0]->list; 468 469 /* Linearly walk of chain index array */ 470 471 for (i=0; i < handle->chain_index_sz; i++) { 472 if (handle->chain_index[i]) { 473 res = strcmp(handle->chain_index[i]->name, name); 474 if (res > 0) 475 break; // One step too far 476 list_pos = &handle->chain_index[i]->list; 477 if (res == 0) 478 break; // Direct hit 479 } 480 } 481 482 return list_pos; 483} 484#endif 485 486static int iptcc_chain_index_alloc(struct xtc_handle *h) 487{ 488 unsigned int list_length = CHAIN_INDEX_BUCKET_LEN; 489 unsigned int array_elems; 490 unsigned int array_mem; 491 492 /* Allocate memory for the chain index array */ 493 array_elems = (h->num_chains / list_length) + 494 (h->num_chains % list_length ? 1 : 0); 495 array_mem = sizeof(h->chain_index) * array_elems; 496 497 debug("Alloc Chain index, elems:%d mem:%d bytes\n", 498 array_elems, array_mem); 499 500 h->chain_index = malloc(array_mem); 501 if (h->chain_index == NULL && array_mem > 0) { 502 h->chain_index_sz = 0; 503 return -ENOMEM; 504 } 505 memset(h->chain_index, 0, array_mem); 506 h->chain_index_sz = array_elems; 507 508 return 1; 509} 510 511static void iptcc_chain_index_free(struct xtc_handle *h) 512{ 513 h->chain_index_sz = 0; 514 free(h->chain_index); 515} 516 517 518#ifdef DEBUG 519static void iptcc_chain_index_dump(struct xtc_handle *h) 520{ 521 unsigned int i = 0; 522 523 /* Dump: contents of chain index array */ 524 for (i=0; i < h->chain_index_sz; i++) { 525 if (h->chain_index[i]) { 526 fprintf(stderr, "Chain index[%d].name: %s\n", 527 i, h->chain_index[i]->name); 528 } 529 } 530} 531#endif 532 533/* Build the chain index */ 534static int iptcc_chain_index_build(struct xtc_handle *h) 535{ 536 unsigned int list_length = CHAIN_INDEX_BUCKET_LEN; 537 unsigned int chains = 0; 538 unsigned int cindex = 0; 539 struct chain_head *c; 540 541 /* Build up the chain index array here */ 542 debug("Building chain index\n"); 543 544 debug("Number of user defined chains:%d bucket_sz:%d array_sz:%d\n", 545 h->num_chains, list_length, h->chain_index_sz); 546 547 if (h->chain_index_sz == 0) 548 return 0; 549 550 list_for_each_entry(c, &h->chains, list) { 551 552 /* Issue: The index array needs to start after the 553 * builtin chains, as they are not sorted */ 554 if (!iptcc_is_builtin(c)) { 555 cindex=chains / list_length; 556 557 /* Safe guard, break out on array limit, this 558 * is useful if chains are added and array is 559 * rebuild, without realloc of memory. */ 560 if (cindex >= h->chain_index_sz) 561 break; 562 563 if ((chains % list_length)== 0) { 564 debug("\nIndex[%d] Chains:", cindex); 565 h->chain_index[cindex] = c; 566 } 567 chains++; 568 } 569 debug("%s, ", c->name); 570 } 571 debug("\n"); 572 573 return 1; 574} 575 576static int iptcc_chain_index_rebuild(struct xtc_handle *h) 577{ 578 debug("REBUILD chain index array\n"); 579 iptcc_chain_index_free(h); 580 if ((iptcc_chain_index_alloc(h)) < 0) 581 return -ENOMEM; 582 iptcc_chain_index_build(h); 583 return 1; 584} 585 586/* Delete chain (pointer) from index array. Removing an element from 587 * the chain list only affects the chain index array, if the chain 588 * index points-to/uses that list pointer. 589 * 590 * There are different strategies, the simple and safe is to rebuild 591 * the chain index every time. The more advanced is to update the 592 * array index to point to the next element, but that requires some 593 * house keeping and boundry checks. The advanced is implemented, as 594 * the simple approach behaves badly when all chains are deleted 595 * because list_for_each processing will always hit the first chain 596 * index, thus causing a rebuild for every chain. 597 */ 598static int iptcc_chain_index_delete_chain(struct chain_head *c, struct xtc_handle *h) 599{ 600 struct list_head *index_ptr, *next; 601 struct chain_head *c2; 602 unsigned int idx, idx2; 603 604 index_ptr = iptcc_bsearch_chain_index(c->name, &idx, h); 605 606 debug("Del chain[%s] c->list:%p index_ptr:%p\n", 607 c->name, &c->list, index_ptr); 608 609 /* Save the next pointer */ 610 next = c->list.next; 611 list_del(&c->list); 612 613 if (index_ptr == &c->list) { /* Chain used as index ptr */ 614 615 /* See if its possible to avoid a rebuild, by shifting 616 * to next pointer. Its possible if the next pointer 617 * is located in the same index bucket. 618 */ 619 c2 = list_entry(next, struct chain_head, list); 620 iptcc_bsearch_chain_index(c2->name, &idx2, h); 621 if (idx != idx2) { 622 /* Rebuild needed */ 623 return iptcc_chain_index_rebuild(h); 624 } else { 625 /* Avoiding rebuild */ 626 debug("Update cindex[%d] with next ptr name:[%s]\n", 627 idx, c2->name); 628 h->chain_index[idx]=c2; 629 return 0; 630 } 631 } 632 return 0; 633} 634 635 636/********************************************************************** 637 * iptc cache utility functions (iptcc_*) 638 **********************************************************************/ 639 640/* Is the given chain builtin (1) or user-defined (0) */ 641static inline unsigned int iptcc_is_builtin(struct chain_head *c) 642{ 643 return (c->hooknum ? 1 : 0); 644} 645 646/* Get a specific rule within a chain */ 647static struct rule_head *iptcc_get_rule_num(struct chain_head *c, 648 unsigned int rulenum) 649{ 650 struct rule_head *r; 651 unsigned int num = 0; 652 653 list_for_each_entry(r, &c->rules, list) { 654 num++; 655 if (num == rulenum) 656 return r; 657 } 658 return NULL; 659} 660 661/* Get a specific rule within a chain backwards */ 662static struct rule_head *iptcc_get_rule_num_reverse(struct chain_head *c, 663 unsigned int rulenum) 664{ 665 struct rule_head *r; 666 unsigned int num = 0; 667 668 list_for_each_entry_reverse(r, &c->rules, list) { 669 num++; 670 if (num == rulenum) 671 return r; 672 } 673 return NULL; 674} 675 676/* Returns chain head if found, otherwise NULL. */ 677static struct chain_head * 678iptcc_find_chain_by_offset(struct xtc_handle *handle, unsigned int offset) 679{ 680 struct list_head *pos; 681 struct list_head *list_start_pos; 682 unsigned int i; 683 684 if (list_empty(&handle->chains)) 685 return NULL; 686 687 /* Find a smart place to start the search */ 688 list_start_pos = iptcc_bsearch_chain_offset(offset, &i, handle); 689 690 /* Note that iptcc_bsearch_chain_offset() skips builtin 691 * chains, but this function is only used for finding jump 692 * targets, and a buildin chain is not a valid jump target */ 693 694 debug("Offset:[%u] starting search at index:[%u]\n", offset, i); 695// list_for_each(pos, &handle->chains) { 696 list_for_each(pos, list_start_pos->prev) { 697 struct chain_head *c = list_entry(pos, struct chain_head, list); 698 debug("."); 699 if (offset >= c->head_offset && offset <= c->foot_offset) { 700 debug("Offset search found chain:[%s]\n", c->name); 701 return c; 702 } 703 } 704 705 return NULL; 706} 707 708/* Returns chain head if found, otherwise NULL. */ 709static struct chain_head * 710iptcc_find_label(const char *name, struct xtc_handle *handle) 711{ 712 struct list_head *pos; 713 struct list_head *list_start_pos; 714 unsigned int i=0; 715 int res; 716 717 if (list_empty(&handle->chains)) 718 return NULL; 719 720 /* First look at builtin chains */ 721 list_for_each(pos, &handle->chains) { 722 struct chain_head *c = list_entry(pos, struct chain_head, list); 723 if (!iptcc_is_builtin(c)) 724 break; 725 if (!strcmp(c->name, name)) 726 return c; 727 } 728 729 /* Find a smart place to start the search via chain index */ 730 //list_start_pos = iptcc_linearly_search_chain_index(name, handle); 731 list_start_pos = iptcc_bsearch_chain_index(name, &i, handle); 732 733 /* Handel if bsearch bails out early */ 734 if (list_start_pos == &handle->chains) { 735 list_start_pos = pos; 736 } 737#ifdef DEBUG 738 else { 739 /* Verify result of bsearch against linearly index search */ 740 struct list_head *test_pos; 741 struct chain_head *test_c, *tmp_c; 742 test_pos = iptcc_linearly_search_chain_index(name, handle); 743 if (list_start_pos != test_pos) { 744 debug("BUG in chain_index search\n"); 745 test_c=list_entry(test_pos, struct chain_head,list); 746 tmp_c =list_entry(list_start_pos,struct chain_head,list); 747 debug("Verify search found:\n"); 748 debug(" Chain:%s\n", test_c->name); 749 debug("BSearch found:\n"); 750 debug(" Chain:%s\n", tmp_c->name); 751 exit(42); 752 } 753 } 754#endif 755 756 /* Initial/special case, no user defined chains */ 757 if (handle->num_chains == 0) 758 return NULL; 759 760 /* Start searching through the chain list */ 761 list_for_each(pos, list_start_pos->prev) { 762 struct chain_head *c = list_entry(pos, struct chain_head, list); 763 res = strcmp(c->name, name); 764 debug("List search name:%s == %s res:%d\n", name, c->name, res); 765 if (res==0) 766 return c; 767 768 /* We can stop earlier as we know list is sorted */ 769 if (res>0 && !iptcc_is_builtin(c)) { /* Walked too far*/ 770 debug(" Not in list, walked too far, sorted list\n"); 771 return NULL; 772 } 773 774 /* Stop on wrap around, if list head is reached */ 775 if (pos == &handle->chains) { 776 debug("Stop, list head reached\n"); 777 return NULL; 778 } 779 } 780 781 debug("List search NOT found name:%s\n", name); 782 return NULL; 783} 784 785/* called when rule is to be removed from cache */ 786static void iptcc_delete_rule(struct rule_head *r) 787{ 788 DEBUGP("deleting rule %p (offset %u)\n", r, r->offset); 789 /* clean up reference count of called chain */ 790 if (r->type == IPTCC_R_JUMP 791 && r->jump) 792 r->jump->references--; 793 794 list_del(&r->list); 795 free(r); 796} 797 798 799/********************************************************************** 800 * RULESET PARSER (blob -> cache) 801 **********************************************************************/ 802 803/* Delete policy rule of previous chain, since cache doesn't contain 804 * chain policy rules. 805 * WARNING: This function has ugly design and relies on a lot of context, only 806 * to be called from specific places within the parser */ 807static int __iptcc_p_del_policy(struct xtc_handle *h, unsigned int num) 808{ 809 const unsigned char *data; 810 811 if (h->chain_iterator_cur) { 812 /* policy rule is last rule */ 813 struct rule_head *pr = (struct rule_head *) 814 h->chain_iterator_cur->rules.prev; 815 816 /* save verdict */ 817 data = GET_TARGET(pr->entry)->data; 818 h->chain_iterator_cur->verdict = *(const int *)data; 819 820 /* save counter and counter_map information */ 821 h->chain_iterator_cur->counter_map.maptype = 822 COUNTER_MAP_ZEROED; 823 h->chain_iterator_cur->counter_map.mappos = num-1; 824 memcpy(&h->chain_iterator_cur->counters, &pr->entry->counters, 825 sizeof(h->chain_iterator_cur->counters)); 826 827 /* foot_offset points to verdict rule */ 828 h->chain_iterator_cur->foot_index = num; 829 h->chain_iterator_cur->foot_offset = pr->offset; 830 831 /* delete rule from cache */ 832 iptcc_delete_rule(pr); 833 h->chain_iterator_cur->num_rules--; 834 835 return 1; 836 } 837 return 0; 838} 839 840/* alphabetically insert a chain into the list */ 841static void iptc_insert_chain(struct xtc_handle *h, struct chain_head *c) 842{ 843 struct chain_head *tmp; 844 struct list_head *list_start_pos; 845 unsigned int i=1; 846 847 /* Find a smart place to start the insert search */ 848 list_start_pos = iptcc_bsearch_chain_index(c->name, &i, h); 849 850 /* Handle the case, where chain.name is smaller than index[0] */ 851 if (i==0 && strcmp(c->name, h->chain_index[0]->name) <= 0) { 852 h->chain_index[0] = c; /* Update chain index head */ 853 list_start_pos = h->chains.next; 854 debug("Update chain_index[0] with %s\n", c->name); 855 } 856 857 /* Handel if bsearch bails out early */ 858 if (list_start_pos == &h->chains) { 859 list_start_pos = h->chains.next; 860 } 861 862 /* sort only user defined chains */ 863 if (!c->hooknum) { 864 list_for_each_entry(tmp, list_start_pos->prev, list) { 865 if (!tmp->hooknum && strcmp(c->name, tmp->name) <= 0) { 866 list_add(&c->list, tmp->list.prev); 867 return; 868 } 869 870 /* Stop if list head is reached */ 871 if (&tmp->list == &h->chains) { 872 debug("Insert, list head reached add to tail\n"); 873 break; 874 } 875 } 876 } 877 878 /* survived till end of list: add at tail */ 879 list_add_tail(&c->list, &h->chains); 880} 881 882/* Another ugly helper function split out of cache_add_entry to make it less 883 * spaghetti code */ 884static void __iptcc_p_add_chain(struct xtc_handle *h, struct chain_head *c, 885 unsigned int offset, unsigned int *num) 886{ 887 struct list_head *tail = h->chains.prev; 888 struct chain_head *ctail; 889 890 __iptcc_p_del_policy(h, *num); 891 892 c->head_offset = offset; 893 c->index = *num; 894 895 /* Chains from kernel are already sorted, as they are inserted 896 * sorted. But there exists an issue when shifting to 1.4.0 897 * from an older version, as old versions allow last created 898 * chain to be unsorted. 899 */ 900 if (iptcc_is_builtin(c)) /* Only user defined chains are sorted*/ 901 list_add_tail(&c->list, &h->chains); 902 else { 903 ctail = list_entry(tail, struct chain_head, list); 904 905 if (strcmp(c->name, ctail->name) > 0 || 906 iptcc_is_builtin(ctail)) 907 list_add_tail(&c->list, &h->chains);/* Already sorted*/ 908 else { 909 iptc_insert_chain(h, c);/* Was not sorted */ 910 911 /* Notice, if chains were not received sorted 912 * from kernel, then an offset bsearch is no 913 * longer valid. 914 */ 915 h->sorted_offsets = 0; 916 917 debug("NOTICE: chain:[%s] was NOT sorted(ctail:%s)\n", 918 c->name, ctail->name); 919 } 920 } 921 922 h->chain_iterator_cur = c; 923} 924 925/* main parser function: add an entry from the blob to the cache */ 926static int cache_add_entry(STRUCT_ENTRY *e, 927 struct xtc_handle *h, 928 STRUCT_ENTRY **prev, 929 unsigned int *num) 930{ 931 unsigned int builtin; 932 unsigned int offset = (char *)e - (char *)h->entries->entrytable; 933 934 DEBUGP("entering..."); 935 936 /* Last entry ("policy rule"). End it.*/ 937 if (iptcb_entry2offset(h,e) + e->next_offset == h->entries->size) { 938 /* This is the ERROR node at the end of the chain */ 939 DEBUGP_C("%u:%u: end of table:\n", *num, offset); 940 941 __iptcc_p_del_policy(h, *num); 942 943 h->chain_iterator_cur = NULL; 944 goto out_inc; 945 } 946 947 /* We know this is the start of a new chain if it's an ERROR 948 * target, or a hook entry point */ 949 950 if (strcmp(GET_TARGET(e)->u.user.name, ERROR_TARGET) == 0) { 951 struct chain_head *c = 952 iptcc_alloc_chain_head((const char *)GET_TARGET(e)->data, 0); 953 DEBUGP_C("%u:%u:new userdefined chain %s: %p\n", *num, offset, 954 (char *)c->name, c); 955 if (!c) { 956 errno = -ENOMEM; 957 return -1; 958 } 959 h->num_chains++; /* New user defined chain */ 960 961 __iptcc_p_add_chain(h, c, offset, num); 962 963 } else if ((builtin = iptcb_ent_is_hook_entry(e, h)) != 0) { 964 struct chain_head *c = 965 iptcc_alloc_chain_head((char *)hooknames[builtin-1], 966 builtin); 967 DEBUGP_C("%u:%u new builtin chain: %p (rules=%p)\n", 968 *num, offset, c, &c->rules); 969 if (!c) { 970 errno = -ENOMEM; 971 return -1; 972 } 973 974 c->hooknum = builtin; 975 976 __iptcc_p_add_chain(h, c, offset, num); 977 978 /* FIXME: this is ugly. */ 979 goto new_rule; 980 } else { 981 /* has to be normal rule */ 982 struct rule_head *r; 983new_rule: 984 985 if (!(r = iptcc_alloc_rule(h->chain_iterator_cur, 986 e->next_offset))) { 987 errno = ENOMEM; 988 return -1; 989 } 990 DEBUGP_C("%u:%u normal rule: %p: ", *num, offset, r); 991 992 r->index = *num; 993 r->offset = offset; 994 memcpy(r->entry, e, e->next_offset); 995 r->counter_map.maptype = COUNTER_MAP_NORMAL_MAP; 996 r->counter_map.mappos = r->index; 997 998 /* handling of jumps, etc. */ 999 if (!strcmp(GET_TARGET(e)->u.user.name, STANDARD_TARGET)) { 1000 STRUCT_STANDARD_TARGET *t; 1001 1002 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e); 1003 if (t->target.u.target_size 1004 != ALIGN(sizeof(STRUCT_STANDARD_TARGET))) { 1005 errno = EINVAL; 1006 free(r); 1007 return -1; 1008 } 1009 1010 if (t->verdict < 0) { 1011 DEBUGP_C("standard, verdict=%d\n", t->verdict); 1012 r->type = IPTCC_R_STANDARD; 1013 } else if (t->verdict == r->offset+e->next_offset) { 1014 DEBUGP_C("fallthrough\n"); 1015 r->type = IPTCC_R_FALLTHROUGH; 1016 } else { 1017 DEBUGP_C("jump, target=%u\n", t->verdict); 1018 r->type = IPTCC_R_JUMP; 1019 /* Jump target fixup has to be deferred 1020 * until second pass, since we migh not 1021 * yet have parsed the target */ 1022 } 1023 } else { 1024 DEBUGP_C("module, target=%s\n", GET_TARGET(e)->u.user.name); 1025 r->type = IPTCC_R_MODULE; 1026 } 1027 1028 list_add_tail(&r->list, &h->chain_iterator_cur->rules); 1029 h->chain_iterator_cur->num_rules++; 1030 } 1031out_inc: 1032 (*num)++; 1033 return 0; 1034} 1035 1036 1037/* parse an iptables blob into it's pieces */ 1038static int parse_table(struct xtc_handle *h) 1039{ 1040 STRUCT_ENTRY *prev; 1041 unsigned int num = 0; 1042 struct chain_head *c; 1043 1044 /* Assume that chains offsets are sorted, this verified during 1045 parsing of ruleset (in __iptcc_p_add_chain())*/ 1046 h->sorted_offsets = 1; 1047 1048 /* First pass: over ruleset blob */ 1049 ENTRY_ITERATE(h->entries->entrytable, h->entries->size, 1050 cache_add_entry, h, &prev, &num); 1051 1052 /* Build the chain index, used for chain list search speedup */ 1053 if ((iptcc_chain_index_alloc(h)) < 0) 1054 return -ENOMEM; 1055 iptcc_chain_index_build(h); 1056 1057 /* Second pass: fixup parsed data from first pass */ 1058 list_for_each_entry(c, &h->chains, list) { 1059 struct rule_head *r; 1060 list_for_each_entry(r, &c->rules, list) { 1061 struct chain_head *lc; 1062 STRUCT_STANDARD_TARGET *t; 1063 1064 if (r->type != IPTCC_R_JUMP) 1065 continue; 1066 1067 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(r->entry); 1068 lc = iptcc_find_chain_by_offset(h, t->verdict); 1069 if (!lc) 1070 return -1; 1071 r->jump = lc; 1072 lc->references++; 1073 } 1074 } 1075 1076 return 1; 1077} 1078 1079 1080/********************************************************************** 1081 * RULESET COMPILATION (cache -> blob) 1082 **********************************************************************/ 1083 1084/* Convenience structures */ 1085struct iptcb_chain_start{ 1086 STRUCT_ENTRY e; 1087 struct xt_error_target name; 1088}; 1089#define IPTCB_CHAIN_START_SIZE (sizeof(STRUCT_ENTRY) + \ 1090 ALIGN(sizeof(struct xt_error_target))) 1091 1092struct iptcb_chain_foot { 1093 STRUCT_ENTRY e; 1094 STRUCT_STANDARD_TARGET target; 1095}; 1096#define IPTCB_CHAIN_FOOT_SIZE (sizeof(STRUCT_ENTRY) + \ 1097 ALIGN(sizeof(STRUCT_STANDARD_TARGET))) 1098 1099struct iptcb_chain_error { 1100 STRUCT_ENTRY entry; 1101 struct xt_error_target target; 1102}; 1103#define IPTCB_CHAIN_ERROR_SIZE (sizeof(STRUCT_ENTRY) + \ 1104 ALIGN(sizeof(struct xt_error_target))) 1105 1106 1107 1108/* compile rule from cache into blob */ 1109static inline int iptcc_compile_rule (struct xtc_handle *h, STRUCT_REPLACE *repl, struct rule_head *r) 1110{ 1111 /* handle jumps */ 1112 if (r->type == IPTCC_R_JUMP) { 1113 STRUCT_STANDARD_TARGET *t; 1114 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(r->entry); 1115 /* memset for memcmp convenience on delete/replace */ 1116 memset(t->target.u.user.name, 0, FUNCTION_MAXNAMELEN); 1117 strcpy(t->target.u.user.name, STANDARD_TARGET); 1118 /* Jumps can only happen to builtin chains, so we 1119 * can safely assume that they always have a header */ 1120 t->verdict = r->jump->head_offset + IPTCB_CHAIN_START_SIZE; 1121 } else if (r->type == IPTCC_R_FALLTHROUGH) { 1122 STRUCT_STANDARD_TARGET *t; 1123 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(r->entry); 1124 t->verdict = r->offset + r->size; 1125 } 1126 1127 /* copy entry from cache to blob */ 1128 memcpy((char *)repl->entries+r->offset, r->entry, r->size); 1129 1130 return 1; 1131} 1132 1133/* compile chain from cache into blob */ 1134static int iptcc_compile_chain(struct xtc_handle *h, STRUCT_REPLACE *repl, struct chain_head *c) 1135{ 1136 int ret; 1137 struct rule_head *r; 1138 struct iptcb_chain_start *head; 1139 struct iptcb_chain_foot *foot; 1140 1141 /* only user-defined chains have heaer */ 1142 if (!iptcc_is_builtin(c)) { 1143 /* put chain header in place */ 1144 head = (void *)repl->entries + c->head_offset; 1145 head->e.target_offset = sizeof(STRUCT_ENTRY); 1146 head->e.next_offset = IPTCB_CHAIN_START_SIZE; 1147 strcpy(head->name.target.u.user.name, ERROR_TARGET); 1148 head->name.target.u.target_size = 1149 ALIGN(sizeof(struct xt_error_target)); 1150 strcpy(head->name.errorname, c->name); 1151 } else { 1152 repl->hook_entry[c->hooknum-1] = c->head_offset; 1153 repl->underflow[c->hooknum-1] = c->foot_offset; 1154 } 1155 1156 /* iterate over rules */ 1157 list_for_each_entry(r, &c->rules, list) { 1158 ret = iptcc_compile_rule(h, repl, r); 1159 if (ret < 0) 1160 return ret; 1161 } 1162 1163 /* put chain footer in place */ 1164 foot = (void *)repl->entries + c->foot_offset; 1165 foot->e.target_offset = sizeof(STRUCT_ENTRY); 1166 foot->e.next_offset = IPTCB_CHAIN_FOOT_SIZE; 1167 strcpy(foot->target.target.u.user.name, STANDARD_TARGET); 1168 foot->target.target.u.target_size = 1169 ALIGN(sizeof(STRUCT_STANDARD_TARGET)); 1170 /* builtin targets have verdict, others return */ 1171 if (iptcc_is_builtin(c)) 1172 foot->target.verdict = c->verdict; 1173 else 1174 foot->target.verdict = RETURN; 1175 /* set policy-counters */ 1176 memcpy(&foot->e.counters, &c->counters, sizeof(STRUCT_COUNTERS)); 1177 1178 return 0; 1179} 1180 1181/* calculate offset and number for every rule in the cache */ 1182static int iptcc_compile_chain_offsets(struct xtc_handle *h, struct chain_head *c, 1183 unsigned int *offset, unsigned int *num) 1184{ 1185 struct rule_head *r; 1186 1187 c->head_offset = *offset; 1188 DEBUGP("%s: chain_head %u, offset=%u\n", c->name, *num, *offset); 1189 1190 if (!iptcc_is_builtin(c)) { 1191 /* Chain has header */ 1192 *offset += sizeof(STRUCT_ENTRY) 1193 + ALIGN(sizeof(struct xt_error_target)); 1194 (*num)++; 1195 } 1196 1197 list_for_each_entry(r, &c->rules, list) { 1198 DEBUGP("rule %u, offset=%u, index=%u\n", *num, *offset, *num); 1199 r->offset = *offset; 1200 r->index = *num; 1201 *offset += r->size; 1202 (*num)++; 1203 } 1204 1205 DEBUGP("%s; chain_foot %u, offset=%u, index=%u\n", c->name, *num, 1206 *offset, *num); 1207 c->foot_offset = *offset; 1208 c->foot_index = *num; 1209 *offset += sizeof(STRUCT_ENTRY) 1210 + ALIGN(sizeof(STRUCT_STANDARD_TARGET)); 1211 (*num)++; 1212 1213 return 1; 1214} 1215 1216/* put the pieces back together again */ 1217static int iptcc_compile_table_prep(struct xtc_handle *h, unsigned int *size) 1218{ 1219 struct chain_head *c; 1220 unsigned int offset = 0, num = 0; 1221 int ret = 0; 1222 1223 /* First pass: calculate offset for every rule */ 1224 list_for_each_entry(c, &h->chains, list) { 1225 ret = iptcc_compile_chain_offsets(h, c, &offset, &num); 1226 if (ret < 0) 1227 return ret; 1228 } 1229 1230 /* Append one error rule at end of chain */ 1231 num++; 1232 offset += sizeof(STRUCT_ENTRY) 1233 + ALIGN(sizeof(struct xt_error_target)); 1234 1235 /* ruleset size is now in offset */ 1236 *size = offset; 1237 return num; 1238} 1239 1240static int iptcc_compile_table(struct xtc_handle *h, STRUCT_REPLACE *repl) 1241{ 1242 struct chain_head *c; 1243 struct iptcb_chain_error *error; 1244 1245 /* Second pass: copy from cache to offsets, fill in jumps */ 1246 list_for_each_entry(c, &h->chains, list) { 1247 int ret = iptcc_compile_chain(h, repl, c); 1248 if (ret < 0) 1249 return ret; 1250 } 1251 1252 /* Append error rule at end of chain */ 1253 error = (void *)repl->entries + repl->size - IPTCB_CHAIN_ERROR_SIZE; 1254 error->entry.target_offset = sizeof(STRUCT_ENTRY); 1255 error->entry.next_offset = IPTCB_CHAIN_ERROR_SIZE; 1256 error->target.target.u.user.target_size = 1257 ALIGN(sizeof(struct xt_error_target)); 1258 strcpy((char *)&error->target.target.u.user.name, ERROR_TARGET); 1259 strcpy((char *)&error->target.errorname, "ERROR"); 1260 1261 return 1; 1262} 1263 1264/********************************************************************** 1265 * EXTERNAL API (operates on cache only) 1266 **********************************************************************/ 1267 1268/* Allocate handle of given size */ 1269static struct xtc_handle * 1270alloc_handle(const char *tablename, unsigned int size, unsigned int num_rules) 1271{ 1272 struct xtc_handle *h; 1273 1274 h = malloc(sizeof(*h)); 1275 if (!h) { 1276 errno = ENOMEM; 1277 return NULL; 1278 } 1279 memset(h, 0, sizeof(*h)); 1280 INIT_LIST_HEAD(&h->chains); 1281 strcpy(h->info.name, tablename); 1282 1283 h->entries = malloc(sizeof(STRUCT_GET_ENTRIES) + size); 1284 if (!h->entries) 1285 goto out_free_handle; 1286 1287 strcpy(h->entries->name, tablename); 1288 h->entries->size = size; 1289 1290 return h; 1291 1292out_free_handle: 1293 free(h); 1294 1295 return NULL; 1296} 1297 1298 1299struct xtc_handle * 1300TC_INIT(const char *tablename) 1301{ 1302 struct xtc_handle *h; 1303 STRUCT_GETINFO info; 1304 unsigned int tmp; 1305 socklen_t s; 1306 int sockfd; 1307 1308 iptc_fn = TC_INIT; 1309 1310 if (strlen(tablename) >= TABLE_MAXNAMELEN) { 1311 errno = EINVAL; 1312 return NULL; 1313 } 1314 1315 sockfd = socket(TC_AF, SOCK_RAW, IPPROTO_RAW); 1316 if (sockfd < 0) 1317 return NULL; 1318 1319retry: 1320 s = sizeof(info); 1321 1322 strcpy(info.name, tablename); 1323 if (getsockopt(sockfd, TC_IPPROTO, SO_GET_INFO, &info, &s) < 0) { 1324 close(sockfd); 1325 return NULL; 1326 } 1327 1328 DEBUGP("valid_hooks=0x%08x, num_entries=%u, size=%u\n", 1329 info.valid_hooks, info.num_entries, info.size); 1330 1331 if ((h = alloc_handle(info.name, info.size, info.num_entries)) 1332 == NULL) { 1333 close(sockfd); 1334 return NULL; 1335 } 1336 1337 /* Initialize current state */ 1338 h->sockfd = sockfd; 1339 h->info = info; 1340 1341 h->entries->size = h->info.size; 1342 1343 tmp = sizeof(STRUCT_GET_ENTRIES) + h->info.size; 1344 1345 if (getsockopt(h->sockfd, TC_IPPROTO, SO_GET_ENTRIES, h->entries, 1346 &tmp) < 0) 1347 goto error; 1348 1349#ifdef IPTC_DEBUG2 1350 { 1351 int fd = open("/tmp/libiptc-so_get_entries.blob", 1352 O_CREAT|O_WRONLY); 1353 if (fd >= 0) { 1354 write(fd, h->entries, tmp); 1355 close(fd); 1356 } 1357 } 1358#endif 1359 1360 if (parse_table(h) < 0) 1361 goto error; 1362 1363 CHECK(h); 1364 return h; 1365error: 1366 TC_FREE(h); 1367 /* A different process changed the ruleset size, retry */ 1368 if (errno == EAGAIN) 1369 goto retry; 1370 return NULL; 1371} 1372 1373void 1374TC_FREE(struct xtc_handle *h) 1375{ 1376 struct chain_head *c, *tmp; 1377 1378 iptc_fn = TC_FREE; 1379 close(h->sockfd); 1380 1381 list_for_each_entry_safe(c, tmp, &h->chains, list) { 1382 struct rule_head *r, *rtmp; 1383 1384 list_for_each_entry_safe(r, rtmp, &c->rules, list) { 1385 free(r); 1386 } 1387 1388 free(c); 1389 } 1390 1391 iptcc_chain_index_free(h); 1392 1393 free(h->entries); 1394 free(h); 1395} 1396 1397static inline int 1398print_match(const STRUCT_ENTRY_MATCH *m) 1399{ 1400 printf("Match name: `%s'\n", m->u.user.name); 1401 return 0; 1402} 1403 1404static int dump_entry(STRUCT_ENTRY *e, struct xtc_handle *const handle); 1405 1406void 1407TC_DUMP_ENTRIES(struct xtc_handle *const handle) 1408{ 1409 iptc_fn = TC_DUMP_ENTRIES; 1410 CHECK(handle); 1411 1412 printf("libiptc v%s. %u bytes.\n", 1413 XTABLES_VERSION, handle->entries->size); 1414 printf("Table `%s'\n", handle->info.name); 1415 printf("Hooks: pre/in/fwd/out/post = %x/%x/%x/%x/%x\n", 1416 handle->info.hook_entry[HOOK_PRE_ROUTING], 1417 handle->info.hook_entry[HOOK_LOCAL_IN], 1418 handle->info.hook_entry[HOOK_FORWARD], 1419 handle->info.hook_entry[HOOK_LOCAL_OUT], 1420 handle->info.hook_entry[HOOK_POST_ROUTING]); 1421 printf("Underflows: pre/in/fwd/out/post = %x/%x/%x/%x/%x\n", 1422 handle->info.underflow[HOOK_PRE_ROUTING], 1423 handle->info.underflow[HOOK_LOCAL_IN], 1424 handle->info.underflow[HOOK_FORWARD], 1425 handle->info.underflow[HOOK_LOCAL_OUT], 1426 handle->info.underflow[HOOK_POST_ROUTING]); 1427 1428 ENTRY_ITERATE(handle->entries->entrytable, handle->entries->size, 1429 dump_entry, handle); 1430} 1431 1432/* Does this chain exist? */ 1433int TC_IS_CHAIN(const char *chain, struct xtc_handle *const handle) 1434{ 1435 iptc_fn = TC_IS_CHAIN; 1436 return iptcc_find_label(chain, handle) != NULL; 1437} 1438 1439static void iptcc_chain_iterator_advance(struct xtc_handle *handle) 1440{ 1441 struct chain_head *c = handle->chain_iterator_cur; 1442 1443 if (c->list.next == &handle->chains) 1444 handle->chain_iterator_cur = NULL; 1445 else 1446 handle->chain_iterator_cur = 1447 list_entry(c->list.next, struct chain_head, list); 1448} 1449 1450/* Iterator functions to run through the chains. */ 1451const char * 1452TC_FIRST_CHAIN(struct xtc_handle *handle) 1453{ 1454 struct chain_head *c = list_entry(handle->chains.next, 1455 struct chain_head, list); 1456 1457 iptc_fn = TC_FIRST_CHAIN; 1458 1459 1460 if (list_empty(&handle->chains)) { 1461 DEBUGP(": no chains\n"); 1462 return NULL; 1463 } 1464 1465 handle->chain_iterator_cur = c; 1466 iptcc_chain_iterator_advance(handle); 1467 1468 DEBUGP(": returning `%s'\n", c->name); 1469 return c->name; 1470} 1471 1472/* Iterator functions to run through the chains. Returns NULL at end. */ 1473const char * 1474TC_NEXT_CHAIN(struct xtc_handle *handle) 1475{ 1476 struct chain_head *c = handle->chain_iterator_cur; 1477 1478 iptc_fn = TC_NEXT_CHAIN; 1479 1480 if (!c) { 1481 DEBUGP(": no more chains\n"); 1482 return NULL; 1483 } 1484 1485 iptcc_chain_iterator_advance(handle); 1486 1487 DEBUGP(": returning `%s'\n", c->name); 1488 return c->name; 1489} 1490 1491/* Get first rule in the given chain: NULL for empty chain. */ 1492const STRUCT_ENTRY * 1493TC_FIRST_RULE(const char *chain, struct xtc_handle *handle) 1494{ 1495 struct chain_head *c; 1496 struct rule_head *r; 1497 1498 iptc_fn = TC_FIRST_RULE; 1499 1500 DEBUGP("first rule(%s): ", chain); 1501 1502 c = iptcc_find_label(chain, handle); 1503 if (!c) { 1504 errno = ENOENT; 1505 return NULL; 1506 } 1507 1508 /* Empty chain: single return/policy rule */ 1509 if (list_empty(&c->rules)) { 1510 DEBUGP_C("no rules, returning NULL\n"); 1511 return NULL; 1512 } 1513 1514 r = list_entry(c->rules.next, struct rule_head, list); 1515 handle->rule_iterator_cur = r; 1516 DEBUGP_C("%p\n", r); 1517 1518 return r->entry; 1519} 1520 1521/* Returns NULL when rules run out. */ 1522const STRUCT_ENTRY * 1523TC_NEXT_RULE(const STRUCT_ENTRY *prev, struct xtc_handle *handle) 1524{ 1525 struct rule_head *r; 1526 1527 iptc_fn = TC_NEXT_RULE; 1528 DEBUGP("rule_iterator_cur=%p...", handle->rule_iterator_cur); 1529 1530 if (handle->rule_iterator_cur == NULL) { 1531 DEBUGP_C("returning NULL\n"); 1532 return NULL; 1533 } 1534 1535 r = list_entry(handle->rule_iterator_cur->list.next, 1536 struct rule_head, list); 1537 1538 iptc_fn = TC_NEXT_RULE; 1539 1540 DEBUGP_C("next=%p, head=%p...", &r->list, 1541 &handle->rule_iterator_cur->chain->rules); 1542 1543 if (&r->list == &handle->rule_iterator_cur->chain->rules) { 1544 handle->rule_iterator_cur = NULL; 1545 DEBUGP_C("finished, returning NULL\n"); 1546 return NULL; 1547 } 1548 1549 handle->rule_iterator_cur = r; 1550 1551 /* NOTE: prev is without any influence ! */ 1552 DEBUGP_C("returning rule %p\n", r); 1553 return r->entry; 1554} 1555 1556/* Returns a pointer to the target name of this position. */ 1557static const char *standard_target_map(int verdict) 1558{ 1559 switch (verdict) { 1560 case RETURN: 1561 return LABEL_RETURN; 1562 break; 1563 case -NF_ACCEPT-1: 1564 return LABEL_ACCEPT; 1565 break; 1566 case -NF_DROP-1: 1567 return LABEL_DROP; 1568 break; 1569 case -NF_QUEUE-1: 1570 return LABEL_QUEUE; 1571 break; 1572 default: 1573 fprintf(stderr, "ERROR: %d not a valid target)\n", 1574 verdict); 1575 abort(); 1576 break; 1577 } 1578 /* not reached */ 1579 return NULL; 1580} 1581 1582/* Returns a pointer to the target name of this position. */ 1583const char *TC_GET_TARGET(const STRUCT_ENTRY *ce, 1584 struct xtc_handle *handle) 1585{ 1586 STRUCT_ENTRY *e = (STRUCT_ENTRY *)ce; 1587 struct rule_head *r = container_of(e, struct rule_head, entry[0]); 1588 const unsigned char *data; 1589 1590 iptc_fn = TC_GET_TARGET; 1591 1592 switch(r->type) { 1593 int spos; 1594 case IPTCC_R_FALLTHROUGH: 1595 return ""; 1596 break; 1597 case IPTCC_R_JUMP: 1598 DEBUGP("r=%p, jump=%p, name=`%s'\n", r, r->jump, r->jump->name); 1599 return r->jump->name; 1600 break; 1601 case IPTCC_R_STANDARD: 1602 data = GET_TARGET(e)->data; 1603 spos = *(const int *)data; 1604 DEBUGP("r=%p, spos=%d'\n", r, spos); 1605 return standard_target_map(spos); 1606 break; 1607 case IPTCC_R_MODULE: 1608 return GET_TARGET(e)->u.user.name; 1609 break; 1610 } 1611 return NULL; 1612} 1613/* Is this a built-in chain? Actually returns hook + 1. */ 1614int 1615TC_BUILTIN(const char *chain, struct xtc_handle *const handle) 1616{ 1617 struct chain_head *c; 1618 1619 iptc_fn = TC_BUILTIN; 1620 1621 c = iptcc_find_label(chain, handle); 1622 if (!c) { 1623 errno = ENOENT; 1624 return 0; 1625 } 1626 1627 return iptcc_is_builtin(c); 1628} 1629 1630/* Get the policy of a given built-in chain */ 1631const char * 1632TC_GET_POLICY(const char *chain, 1633 STRUCT_COUNTERS *counters, 1634 struct xtc_handle *handle) 1635{ 1636 struct chain_head *c; 1637 1638 iptc_fn = TC_GET_POLICY; 1639 1640 DEBUGP("called for chain %s\n", chain); 1641 1642 c = iptcc_find_label(chain, handle); 1643 if (!c) { 1644 errno = ENOENT; 1645 return NULL; 1646 } 1647 1648 if (!iptcc_is_builtin(c)) 1649 return NULL; 1650 1651 *counters = c->counters; 1652 1653 return standard_target_map(c->verdict); 1654} 1655 1656static int 1657iptcc_standard_map(struct rule_head *r, int verdict) 1658{ 1659 STRUCT_ENTRY *e = r->entry; 1660 STRUCT_STANDARD_TARGET *t; 1661 1662 t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e); 1663 1664 if (t->target.u.target_size 1665 != ALIGN(sizeof(STRUCT_STANDARD_TARGET))) { 1666 errno = EINVAL; 1667 return 0; 1668 } 1669 /* memset for memcmp convenience on delete/replace */ 1670 memset(t->target.u.user.name, 0, FUNCTION_MAXNAMELEN); 1671 strcpy(t->target.u.user.name, STANDARD_TARGET); 1672 t->verdict = verdict; 1673 1674 r->type = IPTCC_R_STANDARD; 1675 1676 return 1; 1677} 1678 1679static int 1680iptcc_map_target(struct xtc_handle *const handle, 1681 struct rule_head *r) 1682{ 1683 STRUCT_ENTRY *e = r->entry; 1684 STRUCT_ENTRY_TARGET *t = GET_TARGET(e); 1685 1686 /* Maybe it's empty (=> fall through) */ 1687 if (strcmp(t->u.user.name, "") == 0) { 1688 r->type = IPTCC_R_FALLTHROUGH; 1689 return 1; 1690 } 1691 /* Maybe it's a standard target name... */ 1692 else if (strcmp(t->u.user.name, LABEL_ACCEPT) == 0) 1693 return iptcc_standard_map(r, -NF_ACCEPT - 1); 1694 else if (strcmp(t->u.user.name, LABEL_DROP) == 0) 1695 return iptcc_standard_map(r, -NF_DROP - 1); 1696 else if (strcmp(t->u.user.name, LABEL_QUEUE) == 0) 1697 return iptcc_standard_map(r, -NF_QUEUE - 1); 1698 else if (strcmp(t->u.user.name, LABEL_RETURN) == 0) 1699 return iptcc_standard_map(r, RETURN); 1700 else if (TC_BUILTIN(t->u.user.name, handle)) { 1701 /* Can't jump to builtins. */ 1702 errno = EINVAL; 1703 return 0; 1704 } else { 1705 /* Maybe it's an existing chain name. */ 1706 struct chain_head *c; 1707 DEBUGP("trying to find chain `%s': ", t->u.user.name); 1708 1709 c = iptcc_find_label(t->u.user.name, handle); 1710 if (c) { 1711 DEBUGP_C("found!\n"); 1712 r->type = IPTCC_R_JUMP; 1713 r->jump = c; 1714 c->references++; 1715 return 1; 1716 } 1717 DEBUGP_C("not found :(\n"); 1718 } 1719 1720 /* Must be a module? If not, kernel will reject... */ 1721 /* memset to all 0 for your memcmp convenience: don't clear version */ 1722 memset(t->u.user.name + strlen(t->u.user.name), 1723 0, 1724 FUNCTION_MAXNAMELEN - 1 - strlen(t->u.user.name)); 1725 r->type = IPTCC_R_MODULE; 1726 set_changed(handle); 1727 return 1; 1728} 1729 1730/* Insert the entry `fw' in chain `chain' into position `rulenum'. */ 1731int 1732TC_INSERT_ENTRY(const IPT_CHAINLABEL chain, 1733 const STRUCT_ENTRY *e, 1734 unsigned int rulenum, 1735 struct xtc_handle *handle) 1736{ 1737 struct chain_head *c; 1738 struct rule_head *r; 1739 struct list_head *prev; 1740 1741 iptc_fn = TC_INSERT_ENTRY; 1742 1743 if (!(c = iptcc_find_label(chain, handle))) { 1744 errno = ENOENT; 1745 return 0; 1746 } 1747 1748 /* first rulenum index = 0 1749 first c->num_rules index = 1 */ 1750 if (rulenum > c->num_rules) { 1751 errno = E2BIG; 1752 return 0; 1753 } 1754 1755 /* If we are inserting at the end just take advantage of the 1756 double linked list, insert will happen before the entry 1757 prev points to. */ 1758 if (rulenum == c->num_rules) { 1759 prev = &c->rules; 1760 } else if (rulenum + 1 <= c->num_rules/2) { 1761 r = iptcc_get_rule_num(c, rulenum + 1); 1762 prev = &r->list; 1763 } else { 1764 r = iptcc_get_rule_num_reverse(c, c->num_rules - rulenum); 1765 prev = &r->list; 1766 } 1767 1768 if (!(r = iptcc_alloc_rule(c, e->next_offset))) { 1769 errno = ENOMEM; 1770 return 0; 1771 } 1772 1773 memcpy(r->entry, e, e->next_offset); 1774 r->counter_map.maptype = COUNTER_MAP_SET; 1775 1776 if (!iptcc_map_target(handle, r)) { 1777 free(r); 1778 return 0; 1779 } 1780 1781 list_add_tail(&r->list, prev); 1782 c->num_rules++; 1783 1784 set_changed(handle); 1785 1786 return 1; 1787} 1788 1789/* Atomically replace rule `rulenum' in `chain' with `fw'. */ 1790int 1791TC_REPLACE_ENTRY(const IPT_CHAINLABEL chain, 1792 const STRUCT_ENTRY *e, 1793 unsigned int rulenum, 1794 struct xtc_handle *handle) 1795{ 1796 struct chain_head *c; 1797 struct rule_head *r, *old; 1798 1799 iptc_fn = TC_REPLACE_ENTRY; 1800 1801 if (!(c = iptcc_find_label(chain, handle))) { 1802 errno = ENOENT; 1803 return 0; 1804 } 1805 1806 if (rulenum >= c->num_rules) { 1807 errno = E2BIG; 1808 return 0; 1809 } 1810 1811 /* Take advantage of the double linked list if possible. */ 1812 if (rulenum + 1 <= c->num_rules/2) { 1813 old = iptcc_get_rule_num(c, rulenum + 1); 1814 } else { 1815 old = iptcc_get_rule_num_reverse(c, c->num_rules - rulenum); 1816 } 1817 1818 if (!(r = iptcc_alloc_rule(c, e->next_offset))) { 1819 errno = ENOMEM; 1820 return 0; 1821 } 1822 1823 memcpy(r->entry, e, e->next_offset); 1824 r->counter_map.maptype = COUNTER_MAP_SET; 1825 1826 if (!iptcc_map_target(handle, r)) { 1827 free(r); 1828 return 0; 1829 } 1830 1831 list_add(&r->list, &old->list); 1832 iptcc_delete_rule(old); 1833 1834 set_changed(handle); 1835 1836 return 1; 1837} 1838 1839/* Append entry `fw' to chain `chain'. Equivalent to insert with 1840 rulenum = length of chain. */ 1841int 1842TC_APPEND_ENTRY(const IPT_CHAINLABEL chain, 1843 const STRUCT_ENTRY *e, 1844 struct xtc_handle *handle) 1845{ 1846 struct chain_head *c; 1847 struct rule_head *r; 1848 1849 iptc_fn = TC_APPEND_ENTRY; 1850 if (!(c = iptcc_find_label(chain, handle))) { 1851 DEBUGP("unable to find chain `%s'\n", chain); 1852 errno = ENOENT; 1853 return 0; 1854 } 1855 1856 if (!(r = iptcc_alloc_rule(c, e->next_offset))) { 1857 DEBUGP("unable to allocate rule for chain `%s'\n", chain); 1858 errno = ENOMEM; 1859 return 0; 1860 } 1861 1862 memcpy(r->entry, e, e->next_offset); 1863 r->counter_map.maptype = COUNTER_MAP_SET; 1864 1865 if (!iptcc_map_target(handle, r)) { 1866 DEBUGP("unable to map target of rule for chain `%s'\n", chain); 1867 free(r); 1868 return 0; 1869 } 1870 1871 list_add_tail(&r->list, &c->rules); 1872 c->num_rules++; 1873 1874 set_changed(handle); 1875 1876 return 1; 1877} 1878 1879static inline int 1880match_different(const STRUCT_ENTRY_MATCH *a, 1881 const unsigned char *a_elems, 1882 const unsigned char *b_elems, 1883 unsigned char **maskptr) 1884{ 1885 const STRUCT_ENTRY_MATCH *b; 1886 unsigned int i; 1887 1888 /* Offset of b is the same as a. */ 1889 b = (void *)b_elems + ((unsigned char *)a - a_elems); 1890 1891 if (a->u.match_size != b->u.match_size) 1892 return 1; 1893 1894 if (strcmp(a->u.user.name, b->u.user.name) != 0) 1895 return 1; 1896 1897 *maskptr += ALIGN(sizeof(*a)); 1898 1899 for (i = 0; i < a->u.match_size - ALIGN(sizeof(*a)); i++) 1900 if (((a->data[i] ^ b->data[i]) & (*maskptr)[i]) != 0) 1901 return 1; 1902 *maskptr += i; 1903 return 0; 1904} 1905 1906static inline int 1907target_same(struct rule_head *a, struct rule_head *b,const unsigned char *mask) 1908{ 1909 unsigned int i; 1910 STRUCT_ENTRY_TARGET *ta, *tb; 1911 1912 if (a->type != b->type) 1913 return 0; 1914 1915 ta = GET_TARGET(a->entry); 1916 tb = GET_TARGET(b->entry); 1917 1918 switch (a->type) { 1919 case IPTCC_R_FALLTHROUGH: 1920 return 1; 1921 case IPTCC_R_JUMP: 1922 return a->jump == b->jump; 1923 case IPTCC_R_STANDARD: 1924 return ((STRUCT_STANDARD_TARGET *)ta)->verdict 1925 == ((STRUCT_STANDARD_TARGET *)tb)->verdict; 1926 case IPTCC_R_MODULE: 1927 if (ta->u.target_size != tb->u.target_size) 1928 return 0; 1929 if (strcmp(ta->u.user.name, tb->u.user.name) != 0) 1930 return 0; 1931 1932 for (i = 0; i < ta->u.target_size - sizeof(*ta); i++) 1933 if (((ta->data[i] ^ tb->data[i]) & mask[i]) != 0) 1934 return 0; 1935 return 1; 1936 default: 1937 fprintf(stderr, "ERROR: bad type %i\n", a->type); 1938 abort(); 1939 } 1940} 1941 1942static unsigned char * 1943is_same(const STRUCT_ENTRY *a, 1944 const STRUCT_ENTRY *b, 1945 unsigned char *matchmask); 1946 1947 1948/* find the first rule in `chain' which matches `fw' and remove it unless dry_run is set */ 1949static int delete_entry(const IPT_CHAINLABEL chain, const STRUCT_ENTRY *origfw, 1950 unsigned char *matchmask, struct xtc_handle *handle, 1951 bool dry_run) 1952{ 1953 struct chain_head *c; 1954 struct rule_head *r, *i; 1955 1956 iptc_fn = TC_DELETE_ENTRY; 1957 if (!(c = iptcc_find_label(chain, handle))) { 1958 errno = ENOENT; 1959 return 0; 1960 } 1961 1962 /* Create a rule_head from origfw. */ 1963 r = iptcc_alloc_rule(c, origfw->next_offset); 1964 if (!r) { 1965 errno = ENOMEM; 1966 return 0; 1967 } 1968 1969 memcpy(r->entry, origfw, origfw->next_offset); 1970 r->counter_map.maptype = COUNTER_MAP_NOMAP; 1971 if (!iptcc_map_target(handle, r)) { 1972 DEBUGP("unable to map target of rule for chain `%s'\n", chain); 1973 free(r); 1974 return 0; 1975 } else { 1976 /* iptcc_map_target increment target chain references 1977 * since this is a fake rule only used for matching 1978 * the chain references count is decremented again. 1979 */ 1980 if (r->type == IPTCC_R_JUMP 1981 && r->jump) 1982 r->jump->references--; 1983 } 1984 1985 list_for_each_entry(i, &c->rules, list) { 1986 unsigned char *mask; 1987 1988 mask = is_same(r->entry, i->entry, matchmask); 1989 if (!mask) 1990 continue; 1991 1992 if (!target_same(r, i, mask)) 1993 continue; 1994 1995 /* if we are just doing a dry run, we simply skip the rest */ 1996 if (dry_run) 1997 return 1; 1998 1999 /* If we are about to delete the rule that is the 2000 * current iterator, move rule iterator back. next 2001 * pointer will then point to real next node */ 2002 if (i == handle->rule_iterator_cur) { 2003 handle->rule_iterator_cur = 2004 list_entry(handle->rule_iterator_cur->list.prev, 2005 struct rule_head, list); 2006 } 2007 2008 c->num_rules--; 2009 iptcc_delete_rule(i); 2010 2011 set_changed(handle); 2012 free(r); 2013 return 1; 2014 } 2015 2016 free(r); 2017 errno = ENOENT; 2018 return 0; 2019} 2020 2021/* check whether a specified rule is present */ 2022int TC_CHECK_ENTRY(const IPT_CHAINLABEL chain, const STRUCT_ENTRY *origfw, 2023 unsigned char *matchmask, struct xtc_handle *handle) 2024{ 2025 /* do a dry-run delete to find out whether a matching rule exists */ 2026 return delete_entry(chain, origfw, matchmask, handle, true); 2027} 2028 2029/* Delete the first rule in `chain' which matches `fw'. */ 2030int TC_DELETE_ENTRY(const IPT_CHAINLABEL chain, const STRUCT_ENTRY *origfw, 2031 unsigned char *matchmask, struct xtc_handle *handle) 2032{ 2033 return delete_entry(chain, origfw, matchmask, handle, false); 2034} 2035 2036/* Delete the rule in position `rulenum' in `chain'. */ 2037int 2038TC_DELETE_NUM_ENTRY(const IPT_CHAINLABEL chain, 2039 unsigned int rulenum, 2040 struct xtc_handle *handle) 2041{ 2042 struct chain_head *c; 2043 struct rule_head *r; 2044 2045 iptc_fn = TC_DELETE_NUM_ENTRY; 2046 2047 if (!(c = iptcc_find_label(chain, handle))) { 2048 errno = ENOENT; 2049 return 0; 2050 } 2051 2052 if (rulenum >= c->num_rules) { 2053 errno = E2BIG; 2054 return 0; 2055 } 2056 2057 /* Take advantage of the double linked list if possible. */ 2058 if (rulenum + 1 <= c->num_rules/2) { 2059 r = iptcc_get_rule_num(c, rulenum + 1); 2060 } else { 2061 r = iptcc_get_rule_num_reverse(c, c->num_rules - rulenum); 2062 } 2063 2064 /* If we are about to delete the rule that is the current 2065 * iterator, move rule iterator back. next pointer will then 2066 * point to real next node */ 2067 if (r == handle->rule_iterator_cur) { 2068 handle->rule_iterator_cur = 2069 list_entry(handle->rule_iterator_cur->list.prev, 2070 struct rule_head, list); 2071 } 2072 2073 c->num_rules--; 2074 iptcc_delete_rule(r); 2075 2076 set_changed(handle); 2077 2078 return 1; 2079} 2080 2081/* Flushes the entries in the given chain (ie. empties chain). */ 2082int 2083TC_FLUSH_ENTRIES(const IPT_CHAINLABEL chain, struct xtc_handle *handle) 2084{ 2085 struct chain_head *c; 2086 struct rule_head *r, *tmp; 2087 2088 iptc_fn = TC_FLUSH_ENTRIES; 2089 if (!(c = iptcc_find_label(chain, handle))) { 2090 errno = ENOENT; 2091 return 0; 2092 } 2093 2094 list_for_each_entry_safe(r, tmp, &c->rules, list) { 2095 iptcc_delete_rule(r); 2096 } 2097 2098 c->num_rules = 0; 2099 2100 set_changed(handle); 2101 2102 return 1; 2103} 2104 2105/* Zeroes the counters in a chain. */ 2106int 2107TC_ZERO_ENTRIES(const IPT_CHAINLABEL chain, struct xtc_handle *handle) 2108{ 2109 struct chain_head *c; 2110 struct rule_head *r; 2111 2112 iptc_fn = TC_ZERO_ENTRIES; 2113 if (!(c = iptcc_find_label(chain, handle))) { 2114 errno = ENOENT; 2115 return 0; 2116 } 2117 2118 if (c->counter_map.maptype == COUNTER_MAP_NORMAL_MAP) 2119 c->counter_map.maptype = COUNTER_MAP_ZEROED; 2120 2121 list_for_each_entry(r, &c->rules, list) { 2122 if (r->counter_map.maptype == COUNTER_MAP_NORMAL_MAP) 2123 r->counter_map.maptype = COUNTER_MAP_ZEROED; 2124 } 2125 2126 set_changed(handle); 2127 2128 return 1; 2129} 2130 2131STRUCT_COUNTERS * 2132TC_READ_COUNTER(const IPT_CHAINLABEL chain, 2133 unsigned int rulenum, 2134 struct xtc_handle *handle) 2135{ 2136 struct chain_head *c; 2137 struct rule_head *r; 2138 2139 iptc_fn = TC_READ_COUNTER; 2140 CHECK(*handle); 2141 2142 if (!(c = iptcc_find_label(chain, handle))) { 2143 errno = ENOENT; 2144 return NULL; 2145 } 2146 2147 if (!(r = iptcc_get_rule_num(c, rulenum))) { 2148 errno = E2BIG; 2149 return NULL; 2150 } 2151 2152 return &r->entry[0].counters; 2153} 2154 2155int 2156TC_ZERO_COUNTER(const IPT_CHAINLABEL chain, 2157 unsigned int rulenum, 2158 struct xtc_handle *handle) 2159{ 2160 struct chain_head *c; 2161 struct rule_head *r; 2162 2163 iptc_fn = TC_ZERO_COUNTER; 2164 CHECK(handle); 2165 2166 if (!(c = iptcc_find_label(chain, handle))) { 2167 errno = ENOENT; 2168 return 0; 2169 } 2170 2171 if (!(r = iptcc_get_rule_num(c, rulenum))) { 2172 errno = E2BIG; 2173 return 0; 2174 } 2175 2176 if (r->counter_map.maptype == COUNTER_MAP_NORMAL_MAP) 2177 r->counter_map.maptype = COUNTER_MAP_ZEROED; 2178 2179 set_changed(handle); 2180 2181 return 1; 2182} 2183 2184int 2185TC_SET_COUNTER(const IPT_CHAINLABEL chain, 2186 unsigned int rulenum, 2187 STRUCT_COUNTERS *counters, 2188 struct xtc_handle *handle) 2189{ 2190 struct chain_head *c; 2191 struct rule_head *r; 2192 STRUCT_ENTRY *e; 2193 2194 iptc_fn = TC_SET_COUNTER; 2195 CHECK(handle); 2196 2197 if (!(c = iptcc_find_label(chain, handle))) { 2198 errno = ENOENT; 2199 return 0; 2200 } 2201 2202 if (!(r = iptcc_get_rule_num(c, rulenum))) { 2203 errno = E2BIG; 2204 return 0; 2205 } 2206 2207 e = r->entry; 2208 r->counter_map.maptype = COUNTER_MAP_SET; 2209 2210 memcpy(&e->counters, counters, sizeof(STRUCT_COUNTERS)); 2211 2212 set_changed(handle); 2213 2214 return 1; 2215} 2216 2217/* Creates a new chain. */ 2218/* To create a chain, create two rules: error node and unconditional 2219 * return. */ 2220int 2221TC_CREATE_CHAIN(const IPT_CHAINLABEL chain, struct xtc_handle *handle) 2222{ 2223 static struct chain_head *c; 2224 int capacity; 2225 int exceeded; 2226 2227 iptc_fn = TC_CREATE_CHAIN; 2228 2229 /* find_label doesn't cover built-in targets: DROP, ACCEPT, 2230 QUEUE, RETURN. */ 2231 if (iptcc_find_label(chain, handle) 2232 || strcmp(chain, LABEL_DROP) == 0 2233 || strcmp(chain, LABEL_ACCEPT) == 0 2234 || strcmp(chain, LABEL_QUEUE) == 0 2235 || strcmp(chain, LABEL_RETURN) == 0) { 2236 DEBUGP("Chain `%s' already exists\n", chain); 2237 errno = EEXIST; 2238 return 0; 2239 } 2240 2241 if (strlen(chain)+1 > sizeof(IPT_CHAINLABEL)) { 2242 DEBUGP("Chain name `%s' too long\n", chain); 2243 errno = EINVAL; 2244 return 0; 2245 } 2246 2247 c = iptcc_alloc_chain_head(chain, 0); 2248 if (!c) { 2249 DEBUGP("Cannot allocate memory for chain `%s'\n", chain); 2250 errno = ENOMEM; 2251 return 0; 2252 2253 } 2254 handle->num_chains++; /* New user defined chain */ 2255 2256 DEBUGP("Creating chain `%s'\n", chain); 2257 iptc_insert_chain(handle, c); /* Insert sorted */ 2258 2259 /* Inserting chains don't change the correctness of the chain 2260 * index (except if its smaller than index[0], but that 2261 * handled by iptc_insert_chain). It only causes longer lists 2262 * in the buckets. Thus, only rebuild chain index when the 2263 * capacity is exceed with CHAIN_INDEX_INSERT_MAX chains. 2264 */ 2265 capacity = handle->chain_index_sz * CHAIN_INDEX_BUCKET_LEN; 2266 exceeded = handle->num_chains - capacity; 2267 if (exceeded > CHAIN_INDEX_INSERT_MAX) { 2268 debug("Capacity(%d) exceeded(%d) rebuild (chains:%d)\n", 2269 capacity, exceeded, handle->num_chains); 2270 iptcc_chain_index_rebuild(handle); 2271 } 2272 2273 set_changed(handle); 2274 2275 return 1; 2276} 2277 2278/* Get the number of references to this chain. */ 2279int 2280TC_GET_REFERENCES(unsigned int *ref, const IPT_CHAINLABEL chain, 2281 struct xtc_handle *handle) 2282{ 2283 struct chain_head *c; 2284 2285 iptc_fn = TC_GET_REFERENCES; 2286 if (!(c = iptcc_find_label(chain, handle))) { 2287 errno = ENOENT; 2288 return 0; 2289 } 2290 2291 *ref = c->references; 2292 2293 return 1; 2294} 2295 2296/* Deletes a chain. */ 2297int 2298TC_DELETE_CHAIN(const IPT_CHAINLABEL chain, struct xtc_handle *handle) 2299{ 2300 unsigned int references; 2301 struct chain_head *c; 2302 2303 iptc_fn = TC_DELETE_CHAIN; 2304 2305 if (!(c = iptcc_find_label(chain, handle))) { 2306 DEBUGP("cannot find chain `%s'\n", chain); 2307 errno = ENOENT; 2308 return 0; 2309 } 2310 2311 if (TC_BUILTIN(chain, handle)) { 2312 DEBUGP("cannot remove builtin chain `%s'\n", chain); 2313 errno = EINVAL; 2314 return 0; 2315 } 2316 2317 if (!TC_GET_REFERENCES(&references, chain, handle)) { 2318 DEBUGP("cannot get references on chain `%s'\n", chain); 2319 return 0; 2320 } 2321 2322 if (references > 0) { 2323 DEBUGP("chain `%s' still has references\n", chain); 2324 errno = EMLINK; 2325 return 0; 2326 } 2327 2328 if (c->num_rules) { 2329 DEBUGP("chain `%s' is not empty\n", chain); 2330 errno = ENOTEMPTY; 2331 return 0; 2332 } 2333 2334 /* If we are about to delete the chain that is the current 2335 * iterator, move chain iterator forward. */ 2336 if (c == handle->chain_iterator_cur) 2337 iptcc_chain_iterator_advance(handle); 2338 2339 handle->num_chains--; /* One user defined chain deleted */ 2340 2341 //list_del(&c->list); /* Done in iptcc_chain_index_delete_chain() */ 2342 iptcc_chain_index_delete_chain(c, handle); 2343 free(c); 2344 2345 DEBUGP("chain `%s' deleted\n", chain); 2346 2347 set_changed(handle); 2348 2349 return 1; 2350} 2351 2352/* Renames a chain. */ 2353int TC_RENAME_CHAIN(const IPT_CHAINLABEL oldname, 2354 const IPT_CHAINLABEL newname, 2355 struct xtc_handle *handle) 2356{ 2357 struct chain_head *c; 2358 iptc_fn = TC_RENAME_CHAIN; 2359 2360 /* find_label doesn't cover built-in targets: DROP, ACCEPT, 2361 QUEUE, RETURN. */ 2362 if (iptcc_find_label(newname, handle) 2363 || strcmp(newname, LABEL_DROP) == 0 2364 || strcmp(newname, LABEL_ACCEPT) == 0 2365 || strcmp(newname, LABEL_QUEUE) == 0 2366 || strcmp(newname, LABEL_RETURN) == 0) { 2367 errno = EEXIST; 2368 return 0; 2369 } 2370 2371 if (!(c = iptcc_find_label(oldname, handle)) 2372 || TC_BUILTIN(oldname, handle)) { 2373 errno = ENOENT; 2374 return 0; 2375 } 2376 2377 if (strlen(newname)+1 > sizeof(IPT_CHAINLABEL)) { 2378 errno = EINVAL; 2379 return 0; 2380 } 2381 2382 /* This only unlinks "c" from the list, thus no free(c) */ 2383 iptcc_chain_index_delete_chain(c, handle); 2384 2385 /* Change the name of the chain */ 2386 strncpy(c->name, newname, sizeof(IPT_CHAINLABEL)); 2387 2388 /* Insert sorted into to list again */ 2389 iptc_insert_chain(handle, c); 2390 2391 set_changed(handle); 2392 2393 return 1; 2394} 2395 2396/* Sets the policy on a built-in chain. */ 2397int 2398TC_SET_POLICY(const IPT_CHAINLABEL chain, 2399 const IPT_CHAINLABEL policy, 2400 STRUCT_COUNTERS *counters, 2401 struct xtc_handle *handle) 2402{ 2403 struct chain_head *c; 2404 2405 iptc_fn = TC_SET_POLICY; 2406 2407 if (!(c = iptcc_find_label(chain, handle))) { 2408 DEBUGP("cannot find chain `%s'\n", chain); 2409 errno = ENOENT; 2410 return 0; 2411 } 2412 2413 if (!iptcc_is_builtin(c)) { 2414 DEBUGP("cannot set policy of userdefinedchain `%s'\n", chain); 2415 errno = ENOENT; 2416 return 0; 2417 } 2418 2419 if (strcmp(policy, LABEL_ACCEPT) == 0) 2420 c->verdict = -NF_ACCEPT - 1; 2421 else if (strcmp(policy, LABEL_DROP) == 0) 2422 c->verdict = -NF_DROP - 1; 2423 else { 2424 errno = EINVAL; 2425 return 0; 2426 } 2427 2428 if (counters) { 2429 /* set byte and packet counters */ 2430 memcpy(&c->counters, counters, sizeof(STRUCT_COUNTERS)); 2431 c->counter_map.maptype = COUNTER_MAP_SET; 2432 } else { 2433 c->counter_map.maptype = COUNTER_MAP_NOMAP; 2434 } 2435 2436 set_changed(handle); 2437 2438 return 1; 2439} 2440 2441/* Without this, on gcc 2.7.2.3, we get: 2442 libiptc.c: In function `TC_COMMIT': 2443 libiptc.c:833: fixed or forbidden register was spilled. 2444 This may be due to a compiler bug or to impossible asm 2445 statements or clauses. 2446*/ 2447static void 2448subtract_counters(STRUCT_COUNTERS *answer, 2449 const STRUCT_COUNTERS *a, 2450 const STRUCT_COUNTERS *b) 2451{ 2452 answer->pcnt = a->pcnt - b->pcnt; 2453 answer->bcnt = a->bcnt - b->bcnt; 2454} 2455 2456 2457static void counters_nomap(STRUCT_COUNTERS_INFO *newcounters, unsigned int idx) 2458{ 2459 newcounters->counters[idx] = ((STRUCT_COUNTERS) { 0, 0}); 2460 DEBUGP_C("NOMAP => zero\n"); 2461} 2462 2463static void counters_normal_map(STRUCT_COUNTERS_INFO *newcounters, 2464 STRUCT_REPLACE *repl, unsigned int idx, 2465 unsigned int mappos) 2466{ 2467 /* Original read: X. 2468 * Atomic read on replacement: X + Y. 2469 * Currently in kernel: Z. 2470 * Want in kernel: X + Y + Z. 2471 * => Add in X + Y 2472 * => Add in replacement read. 2473 */ 2474 newcounters->counters[idx] = repl->counters[mappos]; 2475 DEBUGP_C("NORMAL_MAP => mappos %u \n", mappos); 2476} 2477 2478static void counters_map_zeroed(STRUCT_COUNTERS_INFO *newcounters, 2479 STRUCT_REPLACE *repl, unsigned int idx, 2480 unsigned int mappos, STRUCT_COUNTERS *counters) 2481{ 2482 /* Original read: X. 2483 * Atomic read on replacement: X + Y. 2484 * Currently in kernel: Z. 2485 * Want in kernel: Y + Z. 2486 * => Add in Y. 2487 * => Add in (replacement read - original read). 2488 */ 2489 subtract_counters(&newcounters->counters[idx], 2490 &repl->counters[mappos], 2491 counters); 2492 DEBUGP_C("ZEROED => mappos %u\n", mappos); 2493} 2494 2495static void counters_map_set(STRUCT_COUNTERS_INFO *newcounters, 2496 unsigned int idx, STRUCT_COUNTERS *counters) 2497{ 2498 /* Want to set counter (iptables-restore) */ 2499 2500 memcpy(&newcounters->counters[idx], counters, 2501 sizeof(STRUCT_COUNTERS)); 2502 2503 DEBUGP_C("SET\n"); 2504} 2505 2506 2507int 2508TC_COMMIT(struct xtc_handle *handle) 2509{ 2510 /* Replace, then map back the counters. */ 2511 STRUCT_REPLACE *repl; 2512 STRUCT_COUNTERS_INFO *newcounters; 2513 struct chain_head *c; 2514 int ret; 2515 size_t counterlen; 2516 int new_number; 2517 unsigned int new_size; 2518 2519 iptc_fn = TC_COMMIT; 2520 CHECK(*handle); 2521 2522 /* Don't commit if nothing changed. */ 2523 if (!handle->changed) 2524 goto finished; 2525 2526 new_number = iptcc_compile_table_prep(handle, &new_size); 2527 if (new_number < 0) { 2528 errno = ENOMEM; 2529 goto out_zero; 2530 } 2531 2532 repl = malloc(sizeof(*repl) + new_size); 2533 if (!repl) { 2534 errno = ENOMEM; 2535 goto out_zero; 2536 } 2537 memset(repl, 0, sizeof(*repl) + new_size); 2538 2539#if 0 2540 TC_DUMP_ENTRIES(*handle); 2541#endif 2542 2543 counterlen = sizeof(STRUCT_COUNTERS_INFO) 2544 + sizeof(STRUCT_COUNTERS) * new_number; 2545 2546 /* These are the old counters we will get from kernel */ 2547 repl->counters = malloc(sizeof(STRUCT_COUNTERS) 2548 * handle->info.num_entries); 2549 if (!repl->counters) { 2550 errno = ENOMEM; 2551 goto out_free_repl; 2552 } 2553 /* These are the counters we're going to put back, later. */ 2554 newcounters = malloc(counterlen); 2555 if (!newcounters) { 2556 errno = ENOMEM; 2557 goto out_free_repl_counters; 2558 } 2559 memset(newcounters, 0, counterlen); 2560 2561 strcpy(repl->name, handle->info.name); 2562 repl->num_entries = new_number; 2563 repl->size = new_size; 2564 2565 repl->num_counters = handle->info.num_entries; 2566 repl->valid_hooks = handle->info.valid_hooks; 2567 2568 DEBUGP("num_entries=%u, size=%u, num_counters=%u\n", 2569 repl->num_entries, repl->size, repl->num_counters); 2570 2571 ret = iptcc_compile_table(handle, repl); 2572 if (ret < 0) { 2573 errno = ret; 2574 goto out_free_newcounters; 2575 } 2576 2577 2578#ifdef IPTC_DEBUG2 2579 { 2580 int fd = open("/tmp/libiptc-so_set_replace.blob", 2581 O_CREAT|O_WRONLY); 2582 if (fd >= 0) { 2583 write(fd, repl, sizeof(*repl) + repl->size); 2584 close(fd); 2585 } 2586 } 2587#endif 2588 2589 ret = setsockopt(handle->sockfd, TC_IPPROTO, SO_SET_REPLACE, repl, 2590 sizeof(*repl) + repl->size); 2591 if (ret < 0) 2592 goto out_free_newcounters; 2593 2594 /* Put counters back. */ 2595 strcpy(newcounters->name, handle->info.name); 2596 newcounters->num_counters = new_number; 2597 2598 list_for_each_entry(c, &handle->chains, list) { 2599 struct rule_head *r; 2600 2601 /* Builtin chains have their own counters */ 2602 if (iptcc_is_builtin(c)) { 2603 DEBUGP("counter for chain-index %u: ", c->foot_index); 2604 switch(c->counter_map.maptype) { 2605 case COUNTER_MAP_NOMAP: 2606 counters_nomap(newcounters, c->foot_index); 2607 break; 2608 case COUNTER_MAP_NORMAL_MAP: 2609 counters_normal_map(newcounters, repl, 2610 c->foot_index, 2611 c->counter_map.mappos); 2612 break; 2613 case COUNTER_MAP_ZEROED: 2614 counters_map_zeroed(newcounters, repl, 2615 c->foot_index, 2616 c->counter_map.mappos, 2617 &c->counters); 2618 break; 2619 case COUNTER_MAP_SET: 2620 counters_map_set(newcounters, c->foot_index, 2621 &c->counters); 2622 break; 2623 } 2624 } 2625 2626 list_for_each_entry(r, &c->rules, list) { 2627 DEBUGP("counter for index %u: ", r->index); 2628 switch (r->counter_map.maptype) { 2629 case COUNTER_MAP_NOMAP: 2630 counters_nomap(newcounters, r->index); 2631 break; 2632 2633 case COUNTER_MAP_NORMAL_MAP: 2634 counters_normal_map(newcounters, repl, 2635 r->index, 2636 r->counter_map.mappos); 2637 break; 2638 2639 case COUNTER_MAP_ZEROED: 2640 counters_map_zeroed(newcounters, repl, 2641 r->index, 2642 r->counter_map.mappos, 2643 &r->entry->counters); 2644 break; 2645 2646 case COUNTER_MAP_SET: 2647 counters_map_set(newcounters, r->index, 2648 &r->entry->counters); 2649 break; 2650 } 2651 } 2652 } 2653 2654#ifdef IPTC_DEBUG2 2655 { 2656 int fd = open("/tmp/libiptc-so_set_add_counters.blob", 2657 O_CREAT|O_WRONLY); 2658 if (fd >= 0) { 2659 write(fd, newcounters, counterlen); 2660 close(fd); 2661 } 2662 } 2663#endif 2664 2665 ret = setsockopt(handle->sockfd, TC_IPPROTO, SO_SET_ADD_COUNTERS, 2666 newcounters, counterlen); 2667 if (ret < 0) 2668 goto out_free_newcounters; 2669 2670 free(repl->counters); 2671 free(repl); 2672 free(newcounters); 2673 2674finished: 2675 return 1; 2676 2677out_free_newcounters: 2678 free(newcounters); 2679out_free_repl_counters: 2680 free(repl->counters); 2681out_free_repl: 2682 free(repl); 2683out_zero: 2684 return 0; 2685} 2686 2687/* Translates errno numbers into more human-readable form than strerror. */ 2688const char * 2689TC_STRERROR(int err) 2690{ 2691 unsigned int i; 2692 struct table_struct { 2693 void *fn; 2694 int err; 2695 const char *message; 2696 } table [] = 2697 { { TC_INIT, EPERM, "Permission denied (you must be root)" }, 2698 { TC_INIT, EINVAL, "Module is wrong version" }, 2699 { TC_INIT, ENOENT, 2700 "Table does not exist (do you need to insmod?)" }, 2701 { TC_DELETE_CHAIN, ENOTEMPTY, "Chain is not empty" }, 2702 { TC_DELETE_CHAIN, EINVAL, "Can't delete built-in chain" }, 2703 { TC_DELETE_CHAIN, EMLINK, 2704 "Can't delete chain with references left" }, 2705 { TC_CREATE_CHAIN, EEXIST, "Chain already exists" }, 2706 { TC_INSERT_ENTRY, E2BIG, "Index of insertion too big" }, 2707 { TC_REPLACE_ENTRY, E2BIG, "Index of replacement too big" }, 2708 { TC_DELETE_NUM_ENTRY, E2BIG, "Index of deletion too big" }, 2709 { TC_READ_COUNTER, E2BIG, "Index of counter too big" }, 2710 { TC_ZERO_COUNTER, E2BIG, "Index of counter too big" }, 2711 { TC_INSERT_ENTRY, ELOOP, "Loop found in table" }, 2712 { TC_INSERT_ENTRY, EINVAL, "Target problem" }, 2713 /* ENOENT for DELETE probably means no matching rule */ 2714 { TC_DELETE_ENTRY, ENOENT, 2715 "Bad rule (does a matching rule exist in that chain?)" }, 2716 { TC_SET_POLICY, ENOENT, 2717 "Bad built-in chain name" }, 2718 { TC_SET_POLICY, EINVAL, 2719 "Bad policy name" }, 2720 2721 { NULL, 0, "Incompatible with this kernel" }, 2722 { NULL, ENOPROTOOPT, "iptables who? (do you need to insmod?)" }, 2723 { NULL, ENOSYS, "Will be implemented real soon. I promise ;)" }, 2724 { NULL, ENOMEM, "Memory allocation problem" }, 2725 { NULL, ENOENT, "No chain/target/match by that name" }, 2726 }; 2727 2728 for (i = 0; i < sizeof(table)/sizeof(struct table_struct); i++) { 2729 if ((!table[i].fn || table[i].fn == iptc_fn) 2730 && table[i].err == err) 2731 return table[i].message; 2732 } 2733 2734 return strerror(err); 2735} 2736 2737const struct xtc_ops TC_OPS = { 2738 .commit = TC_COMMIT, 2739 .free = TC_FREE, 2740 .builtin = TC_BUILTIN, 2741 .is_chain = TC_IS_CHAIN, 2742 .flush_entries = TC_FLUSH_ENTRIES, 2743 .create_chain = TC_CREATE_CHAIN, 2744 .set_policy = TC_SET_POLICY, 2745 .strerror = TC_STRERROR, 2746}; 2747