tools/iptables-test.c

   1 /*
   2  *  Connection Manager
   3  *
   4  *  Copyright (C) 2007-2010  Intel Corporation. All rights reserved.
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License version 2 as
   8  *  published by the Free Software Foundation.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18  *
  19  */
  20
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <sys/errno.h>
  26 #include <sys/socket.h>
  27 #include <xtables.h>
  28
  29 #include <linux/netfilter_ipv4/ip_tables.h>
  30
  31 #include <glib.h>
  32
  33 static const char *hooknames[] = {
  34         [NF_IP_PRE_ROUTING]     = "PREROUTING",
  35         [NF_IP_LOCAL_IN]        = "INPUT",
  36         [NF_IP_FORWARD]         = "FORWARD",
  37         [NF_IP_LOCAL_OUT]       = "OUTPUT",
  38         [NF_IP_POST_ROUTING]    = "POSTROUTING",
  39 };
  40
  41 #define LABEL_ACCEPT  "ACCEPT"
  42 #define LABEL_DROP    "DROP"
  43 #define LABEL_QUEUE   "QUEUE"
  44 #define LABEL_RETURN  "RETURN"
  45
  46 /* fn returns 0 to continue iteration */
  47 #define _XT_ENTRY_ITERATE_CONTINUE(type, entries, size, n, fn, args...) \
  48 ({                                                              \
  49         unsigned int __i;                                       \
  50         int __n;                                                \
  51         int __ret = 0;                                          \
  52         type *__entry;                                          \
  53                                                                 \
  54         for (__i = 0, __n = 0; __i < (size);                    \
  55              __i += __entry->next_offset, __n++) {              \
  56                 __entry = (void *)(entries) + __i;              \
  57                 if (__n < n)                                    \
  58                         continue;                               \
  59                                                                 \
  60                 __ret = fn(__entry,  ## args);                  \
  61                 if (__ret != 0)                                 \
  62                         break;                                  \
  63         }                                                       \
  64         __ret;                                                  \
  65 })
  66
  67 /* fn returns 0 to continue iteration */
  68 #define _XT_ENTRY_ITERATE(type, entries, size, fn, args...) \
  69         _XT_ENTRY_ITERATE_CONTINUE(type, entries, size, 0, fn, args)
  70
  71 #define ENTRY_ITERATE(entries, size, fn, args...) \
  72         _XT_ENTRY_ITERATE(struct ipt_entry, entries, size, fn, ## args)
  73
  74 #define MIN_ALIGN (__alignof__(struct ipt_entry))
  75
  76 #define ALIGN(s) (((s) + ((MIN_ALIGN)-1)) & ~((MIN_ALIGN)-1))
  77
  78 struct ipt_error_target {
  79         struct xt_entry_target t;
  80         char error[IPT_TABLE_MAXNAMELEN];
  81 };
  82
  83 struct connman_iptables_entry {
  84         int builtin;
  85         int std_target;
  86         int jump_offset;
  87
  88         struct ipt_entry *entry;
  89 };
  90
  91 struct connman_iptables {
  92         int ipt_sock;
  93
  94         struct ipt_getinfo *info;
  95         struct ipt_get_entries *blob_entries;
  96
  97         unsigned int num_entries;
  98         unsigned int old_entries;
  99         unsigned int size;
 100
 101         GList *entries;
 102 };
 103
 104
 105 static struct ipt_entry *get_entry(struct connman_iptables *table,
 106                                         unsigned int offset)
 107 {
 108         return (struct ipt_entry *)((char *)table->blob_entries->entrytable +
 109                                                                         offset);
 110 }
 111
 112 static int is_hook_entry(struct connman_iptables *table,
 113                                 struct ipt_entry *entry)
 114 {
 115         unsigned int i;
 116
 117         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
 118                 if ((table->info->valid_hooks & (1 << i))
 119                 && get_entry(table, table->info->hook_entry[i]) == entry)
 120                         return i;
 121         }
 122
 123         return -1;
 124 }
 125
 126 static unsigned long entry_to_offset(struct connman_iptables *table,
 127                                         struct ipt_entry *entry)
 128 {
 129         return (void *)entry - (void *)table->blob_entries->entrytable;
 130 }
 131
 132 static int target_to_verdict(char *target_name)
 133 {
 134         if (!strcmp(target_name, LABEL_ACCEPT))
 135                 return -NF_ACCEPT - 1;
 136
 137         if (!strcmp(target_name, LABEL_DROP))
 138                 return -NF_DROP - 1;
 139
 140         if (!strcmp(target_name, LABEL_QUEUE))
 141                 return -NF_QUEUE - 1;
 142
 143         if (!strcmp(target_name, LABEL_RETURN))
 144                 return XT_RETURN;
 145
 146         return 0;
 147 }
 148
 149 static gboolean is_builtin_target(char *target_name)
 150 {
 151         if (!strcmp(target_name, LABEL_ACCEPT) ||
 152                 !strcmp(target_name, LABEL_DROP) ||
 153                 !strcmp(target_name, LABEL_QUEUE) ||
 154                 !strcmp(target_name, LABEL_RETURN))
 155                 return TRUE;
 156
 157         return FALSE;
 158 }
 159
 160 static gboolean is_chain(struct connman_iptables *table,
 161                                 struct connman_iptables_entry *e)
 162 {
 163         int builtin;
 164         struct ipt_entry *entry;
 165         struct xt_entry_target *target;
 166
 167         entry = e->entry;
 168         builtin = is_hook_entry(table, entry);
 169         if (builtin >= 0)
 170                 return TRUE;
 171
 172         target = ipt_get_target(entry);
 173         if (!strcmp(target->u.user.name, IPT_ERROR_TARGET))
 174                 return TRUE;
 175
 176         return FALSE;
 177 }
 178
 179 static GList *find_chain_tail(struct connman_iptables *table,
 180                                 char *chain_name)
 181 {
 182         GList *chain_head, *list;
 183         struct connman_iptables_entry *head, *tail;
 184         struct ipt_entry *entry;
 185         struct xt_entry_target *target;
 186         int builtin;
 187
 188         /* First we look for the head */
 189         for (list = table->entries; list; list = list->next) {
 190                 head = list->data;
 191                 entry = head->entry;
 192
 193                 /* Buit-in chain */
 194                 builtin = is_hook_entry(table, entry);
 195                 if (builtin >= 0 && !strcmp(hooknames[builtin], chain_name))
 196                         break;
 197
 198                 /* User defined chain */
 199                 target = ipt_get_target(entry);
 200                 if (!strcmp(target->u.user.name, IPT_ERROR_TARGET) &&
 201                     !strcmp((char *)target->data, chain_name))
 202                         break;
 203         }
 204
 205         if (list == NULL)
 206                 return NULL;
 207
 208         chain_head = list;
 209
 210         /* Then we look for the next chain */
 211         for (list = chain_head->next; list; list = list->next) {
 212                 tail = list->data;
 213                 entry = tail->entry;
 214
 215                 if (is_chain(table, tail))
 216                         return list;
 217         }
 218
 219         /* Nothing found, we return the table end */
 220         return g_list_last(table->entries);
 221 }
 222
 223 static int connman_add_entry(struct connman_iptables *table,
 224                                 struct ipt_entry *entry, GList *before)
 225 {
 226         struct connman_iptables_entry *e;
 227
 228         if (table == NULL)
 229                 return -1;
 230
 231         e = g_try_malloc0(sizeof(struct connman_iptables_entry));
 232         if (e == NULL)
 233                 return -1;
 234
 235         e->entry = entry;
 236
 237         table->entries = g_list_insert_before(table->entries, before, e);
 238         table->num_entries++;
 239         table->size += entry->next_offset;
 240
 241         return 0;
 242 }
 243
 244 static int connman_iptables_add_chain(struct connman_iptables *table,
 245                                         char *name)
 246 {
 247         GList *last;
 248         struct ipt_entry *entry_head;
 249         struct ipt_entry *entry_return;
 250         struct ipt_error_target *error;
 251         struct ipt_standard_target *standard;
 252         u_int16_t entry_head_size, entry_return_size;
 253
 254         last = g_list_last(table->entries);
 255
 256         /*
 257          * An empty chain is composed of:
 258          * - A head entry, with no match and an error target.
 259          *   The error target data is the chain name.
 260          * - A tail entry, with no match and a standard target.
 261          *   The standard target verdict is XT_RETURN (return to the
 262          *   caller).
 263          */
 264
 265         /* head entry */
 266         entry_head_size = sizeof(struct ipt_entry) +
 267                                 sizeof(struct ipt_error_target);
 268         entry_head = g_try_malloc0(entry_head_size);
 269         if (entry_head == NULL)
 270                 goto err;
 271
 272         memset(entry_head, 0, entry_head_size);
 273
 274         entry_head->target_offset = sizeof(struct ipt_entry);
 275         entry_head->next_offset = entry_head_size;
 276
 277         error = (struct ipt_error_target *) entry_head->elems;
 278         strcpy(error->t.u.user.name, IPT_ERROR_TARGET);
 279         error->t.u.user.target_size = ALIGN(sizeof(struct ipt_error_target));
 280         strcpy(error->error, name);
 281
 282         if (connman_add_entry(table, entry_head, last) < 0)
 283                 goto err;
 284
 285         /* tail entry */
 286         entry_return_size = sizeof(struct ipt_entry) +
 287                                 sizeof(struct ipt_standard_target);
 288         entry_return = g_try_malloc0(entry_return_size);
 289         if (entry_return == NULL)
 290                 goto err;
 291
 292         memset(entry_return, 0, entry_return_size);
 293
 294         entry_return->target_offset = sizeof(struct ipt_entry);
 295         entry_return->next_offset = entry_return_size;
 296
 297         standard = (struct ipt_standard_target *) entry_return->elems;
 298         standard->target.u.user.target_size =
 299                                 ALIGN(sizeof(struct ipt_standard_target));
 300         standard->verdict = XT_RETURN;
 301
 302         if (connman_add_entry(table, entry_return, last) < 0)
 303                 goto err;
 304
 305         return 0;
 306
 307 err:
 308         g_free(entry_head);
 309         g_free(entry_return);
 310
 311         return -ENOMEM;
 312 }
 313
 314 static struct ipt_entry *
 315 new_builtin_rule(char *target_name,
 316                 char *match_name, int match_argc, char **match_argv)
 317 {
 318         struct ipt_entry *new_entry;
 319         size_t match_size, target_size;
 320         struct xtables_match *xt_m;
 321         struct xt_standard_target *target;
 322
 323         xt_m = NULL;
 324         match_size = 0;
 325
 326         if (match_name) {
 327                 xt_m = xtables_find_match(match_name, XTF_TRY_LOAD, NULL);
 328                 if (xt_m == NULL)
 329                         return NULL;
 330
 331                 match_size = ALIGN(sizeof(struct xt_entry_match)) + xt_m->size;
 332         }
 333
 334         target_size = ALIGN(sizeof(struct xt_standard_target));
 335
 336         new_entry = g_try_malloc0(sizeof(struct ipt_entry) + target_size +
 337                                                                 match_size);
 338         if (new_entry == NULL)
 339                 return NULL;
 340
 341         new_entry->target_offset = sizeof(struct ipt_entry) + match_size;
 342         new_entry->next_offset = sizeof(struct ipt_entry) + target_size +
 343                                                                 match_size;
 344
 345         if (xt_m) {
 346                 struct xt_entry_match *entry_match;
 347
 348                 entry_match = (struct xt_entry_match *)new_entry->elems;
 349                 entry_match->u.match_size = match_size;
 350                 strcpy(entry_match->u.user.name, xt_m->name);
 351                 entry_match->u.user.revision = xt_m->revision;
 352                 if (xt_m->init != NULL)
 353                         xt_m->init(entry_match);
 354         }
 355
 356         target = (struct xt_standard_target *)(new_entry->elems + match_size);
 357         strcpy(target->target.u.user.name, IPT_STANDARD_TARGET);
 358         target->target.u.user.target_size =
 359                                 ALIGN(sizeof(struct ipt_standard_target));
 360         target->verdict = target_to_verdict(target_name);
 361
 362         return new_entry;
 363 }
 364
 365 static struct ipt_entry *
 366 new_custom_rule(char *target_name, int target_argc, char **target_argv,
 367                 char *match_name, int match_argc, char **match_argv)
 368 {
 369         return NULL;
 370 }
 371
 372 static struct ipt_entry *
 373 new_rule(char *target_name, int target_argc, char **target_argv,
 374                 char *match_name, int match_argc, char **match_argv)
 375 {
 376         struct ipt_entry *new_entry;
 377
 378         if (is_builtin_target(target_name))
 379                 new_entry = new_builtin_rule(target_name,
 380                                         match_name, match_argc, match_argv);
 381         else
 382                 new_entry = new_custom_rule(target_name,
 383                                         target_argc, target_argv,
 384                                         match_name, match_argc, match_argv);
 385
 386         return new_entry;
 387 }
 388
 389 static int
 390 connman_iptables_add_rule(struct connman_iptables *table, char *chain_name,
 391                         char *target_name, int target_argc, char **target_argv,
 392                         char *match_name, int match_argc, char **match_argv)
 393 {
 394         GList *chain_tail;
 395         struct ipt_entry *new_entry;
 396
 397         chain_tail = find_chain_tail(table, chain_name);
 398         if (chain_tail == NULL)
 399                 return -EINVAL;
 400
 401         printf("Chains found\n");
 402
 403         new_entry = new_rule(target_name, target_argc, target_argv,
 404                                 match_name, match_argc, match_argv);
 405         if (new_entry == NULL)
 406                 return -EINVAL;
 407
 408         return connman_add_entry(table, new_entry, chain_tail->prev);
 409 }
 410
 411 static struct ipt_replace *
 412 connman_iptables_blob(struct connman_iptables *table)
 413 {
 414         struct ipt_replace *r;
 415         GList *list;
 416         struct connman_iptables_entry *e;
 417         unsigned char *entry_index;
 418
 419         r = g_try_malloc0(sizeof(struct ipt_replace) + table->size);
 420         if (r == NULL)
 421                 return NULL;
 422
 423         memset(r, 0, sizeof(*r) + table->size);
 424
 425         r->counters = g_try_malloc0(sizeof(struct xt_counters)
 426                                 * table->num_entries);
 427         if (r->counters == NULL) {
 428                 g_free(r);
 429                 return NULL;
 430         }
 431
 432         strcpy(r->name, table->info->name);
 433         r->num_entries = table->num_entries;
 434         r->size = table->size;
 435
 436         r->num_counters = table->old_entries;
 437         r->valid_hooks  = table->info->valid_hooks;
 438
 439         memcpy(r->hook_entry, table->info->hook_entry,
 440                                 sizeof(table->info->hook_entry));
 441         memcpy(r->underflow, table->info->underflow,
 442                                 sizeof(table->info->underflow));
 443
 444         entry_index = (unsigned char *)r->entries;
 445         for (list = table->entries; list; list = list->next) {
 446                 e = list->data;
 447
 448                 memcpy(entry_index, e->entry, e->entry->next_offset);
 449                 entry_index += e->entry->next_offset;
 450         }
 451
 452         return r;
 453 }
 454
 455 static void dump_target(struct connman_iptables *table,
 456                                 struct ipt_entry *entry)
 457
 458 {
 459         struct xtables_target *xt_t;
 460         struct xt_entry_target *target;
 461
 462         target = ipt_get_target(entry);
 463
 464         if (!strcmp(target->u.user.name, IPT_STANDARD_TARGET)) {
 465                 struct xt_standard_target *t;
 466
 467                 t = (struct xt_standard_target *)target;
 468
 469                 switch (t->verdict) {
 470                 case XT_RETURN:
 471                         printf("\ttarget RETURN\n");
 472                         break;
 473
 474                 case -NF_ACCEPT - 1:
 475                         printf("\ttarget ACCEPT\n");
 476                         break;
 477
 478                 case -NF_DROP - 1:
 479                         printf("\ttarget DROP\n");
 480                         break;
 481
 482                 case -NF_QUEUE - 1:
 483                         printf("\ttarget QUEUE\n");
 484                         break;
 485
 486                 case -NF_STOP - 1:
 487                         printf("\ttarget STOP\n");
 488                         break;
 489
 490                 default:
 491                         printf("\tJUMP @%p (0x%x)\n",
 492                                 (char*)table->blob_entries->entrytable +
 493                                 t->verdict, t->verdict);
 494                         break;
 495                 }
 496
 497                 xt_t = xtables_find_target(IPT_STANDARD_TARGET,
 498                                                 XTF_LOAD_MUST_SUCCEED);
 499
 500                 if(xt_t->print != NULL)
 501                         xt_t->print(NULL, target, 1);
 502         } else {
 503                 printf("\ttarget %s\n", target->u.user.name);
 504
 505                 xt_t = xtables_find_target(target->u.user.name, XTF_TRY_LOAD);
 506                 if (xt_t == NULL)
 507                         return;
 508
 509                 if(xt_t->print != NULL)
 510                         xt_t->print(NULL, target, 1);
 511         }
 512 }
 513
 514 static void dump_match(struct connman_iptables *table, struct ipt_entry *entry)
 515 {
 516         struct xtables_match *xt_m;
 517         struct xt_entry_match *match;
 518
 519         match = (struct xt_entry_match *) entry->elems;
 520
 521         if (!strlen(match->u.user.name))
 522                 return;
 523
 524         xt_m = xtables_find_match(match->u.user.name, XTF_TRY_LOAD, NULL);
 525         if (xt_m == NULL)
 526                 goto out;
 527
 528         if(xt_m->print != NULL) {
 529                 printf("\tmatch ");
 530                 xt_m->print(NULL, match, 1);
 531                 printf("\n");
 532
 533                 return;
 534         }
 535
 536 out:
 537         printf("\tmatch %s\n", match->u.user.name);
 538
 539 }
 540
 541 static int connman_iptables_dump_entry(struct ipt_entry *entry,
 542                                         struct connman_iptables *table)
 543 {
 544         struct xt_entry_target *target;
 545         unsigned int offset;
 546         int builtin;
 547
 548         offset = (char *)entry - (char *)table->blob_entries->entrytable;
 549         target = ipt_get_target(entry);
 550         builtin = is_hook_entry(table, entry);
 551
 552         if (entry_to_offset(table, entry) + entry->next_offset ==
 553                                         table->blob_entries->size) {
 554                 printf("End of CHAIN 0x%x\n", offset);
 555                 return 0;
 556         }
 557
 558         if (!strcmp(target->u.user.name, IPT_ERROR_TARGET)) {
 559                 printf("USER CHAIN (%s) %p  match %p  target %p  size %d\n",
 560                         target->data, entry, entry->elems,
 561                         (char *)entry + entry->target_offset,
 562                                 entry->next_offset);
 563
 564                 return 0;
 565         } else if (builtin >= 0) {
 566                 printf("CHAIN (%s) %p  match %p  target %p  size %d\n",
 567                         hooknames[builtin], entry, entry->elems,
 568                         (char *)entry + entry->target_offset,
 569                                 entry->next_offset);
 570         } else {
 571                 printf("RULE %p  match %p  target %p  size %d\n", entry,
 572                         entry->elems,
 573                         (char *)entry + entry->target_offset,
 574                                 entry->next_offset);
 575         }
 576
 577         dump_match(table, entry);
 578         dump_target(table, entry);
 579
 580         return 0;
 581 }
 582
 583 static void connman_iptables_dump(struct connman_iptables *table)
 584 {
 585         printf("%s valid_hooks=0x%08x, num_entries=%u, size=%u\n",
 586                 table->info->name,
 587                 table->info->valid_hooks, table->info->num_entries,
 588                 table->info->size);
 589
 590         ENTRY_ITERATE(table->blob_entries->entrytable,
 591                         table->blob_entries->size,
 592                         connman_iptables_dump_entry, table);
 593
 594 }
 595
 596 static int connman_iptables_get_entries(struct connman_iptables *table)
 597 {
 598         socklen_t entry_size;
 599
 600         entry_size = sizeof(struct ipt_get_entries) + table->info->size;
 601
 602         return getsockopt(table->ipt_sock, IPPROTO_IP, IPT_SO_GET_ENTRIES,
 603                                 table->blob_entries, &entry_size);
 604 }
 605
 606 static int connman_iptables_replace(struct connman_iptables *table,
 607                                         struct ipt_replace *r)
 608 {
 609         return setsockopt(table->ipt_sock, IPPROTO_IP, IPT_SO_SET_REPLACE, r,
 610                          sizeof(*r) + r->size);
 611 }
 612
 613 static void connman_iptables_cleanup(struct connman_iptables *table)
 614 {
 615         close(table->ipt_sock);
 616         g_free(table->info);
 617         g_free(table->blob_entries);
 618         g_free(table);
 619 }
 620
 621 static int add_entry(struct ipt_entry *entry, struct connman_iptables *table)
 622 {
 623         return connman_add_entry(table, entry, NULL);
 624 }
 625
 626 static struct connman_iptables *connman_iptables_init(const char *table_name)
 627 {
 628         struct connman_iptables *table;
 629         socklen_t s;
 630
 631         table =  g_try_new0(struct connman_iptables, 1);
 632         if (table == NULL)
 633                 return NULL;
 634
 635         table->info =  g_try_new0(struct ipt_getinfo, 1);
 636         if (table->info == NULL)
 637                 goto err;
 638
 639         table->ipt_sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
 640         if (table->ipt_sock < 0)
 641                 goto err;
 642
 643         s = sizeof(*table->info);
 644         strcpy(table->info->name, table_name);
 645         if (getsockopt(table->ipt_sock, IPPROTO_IP, IPT_SO_GET_INFO,
 646                                                 table->info, &s) < 0)
 647                 goto err;
 648
 649         table->blob_entries = g_try_malloc0(sizeof(struct ipt_get_entries) +
 650                                                 table->info->size);
 651         if (table->blob_entries == NULL)
 652                 goto err;
 653
 654         strcpy(table->blob_entries->name, table_name);
 655         table->blob_entries->size = table->info->size;
 656
 657         if (connman_iptables_get_entries(table) < 0)
 658                 goto err;
 659
 660         table->num_entries = 0;
 661         table->old_entries = table->info->num_entries;
 662         table->size = 0;
 663
 664         ENTRY_ITERATE(table->blob_entries->entrytable,
 665                         table->blob_entries->size,
 666                                 add_entry, table);
 667
 668
 669         return table;
 670
 671 err:
 672
 673         connman_iptables_cleanup(table);
 674
 675         return NULL;
 676 }
 677
 678 int main(int argc, char *argv[])
 679 {
 680         struct ipt_replace *repl;
 681         struct connman_iptables *table;
 682
 683         xtables_init();
 684         xtables_set_nfproto(NFPROTO_IPV4);
 685
 686         table = connman_iptables_init("filter");
 687         if (table == NULL)
 688                 return -1;
 689
 690         connman_iptables_dump(table);
 691
 692         if (argv[1]) {
 693                 connman_iptables_add_chain(table, argv[1]);
 694
 695                 connman_iptables_add_rule(table, argv[1],
 696                                         "ACCEPT", 0, NULL,
 697                                         NULL, 0, NULL);
 698
 699                 repl = connman_iptables_blob(table);
 700
 701                 connman_iptables_replace(table, repl);
 702         }
 703
 704         connman_iptables_cleanup(table);
 705
 706         return 0;
 707 }