utils.c

   1 /*
   2  * firewall3 - 3rd OpenWrt UCI firewall implementation
   3  *
   4  *   Copyright (C) 2013 Jo-Philipp Wich <jo@mein.io>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include "utils.h"
  21 #include "options.h"
  22
  23 #include "zones.h"
  24 #include "ipsets.h"
  25
  26
  27 static int lock_fd = -1;
  28 static pid_t pipe_pid = -1;
  29 static FILE *pipe_fd = NULL;
  30
  31 bool fw3_pr_debug = false;
  32
  33
  34 static void
  35 warn_elem_section_name(struct uci_section *s, bool find_name)
  36 {
  37         int i = 0;
  38         struct uci_option *o;
  39         struct uci_element *tmp;
  40
  41         if (s->anonymous)
  42         {
  43                 uci_foreach_element(&s->package->sections, tmp)
  44                 {
  45                         if (strcmp(uci_to_section(tmp)->type, s->type))
  46                                 continue;
  47
  48                         if (&s->e == tmp)
  49                                 break;
  50
  51                         i++;
  52                 }
  53
  54                 fprintf(stderr, "@%s[%d]", s->type, i);
  55
  56                 if (find_name)
  57                 {
  58                         uci_foreach_element(&s->options, tmp)
  59                         {
  60                                 o = uci_to_option(tmp);
  61
  62                                 if (!strcmp(tmp->name, "name") && (o->type == UCI_TYPE_STRING))
  63                                 {
  64                                         fprintf(stderr, " (%s)", o->v.string);
  65                                         break;
  66                                 }
  67                         }
  68                 }
  69         }
  70         else
  71         {
  72                 fprintf(stderr, "'%s'", s->e.name);
  73         }
  74
  75         if (find_name)
  76                 fprintf(stderr, " ");
  77 }
  78
  79 void
  80 warn_elem(struct uci_element *e, const char *format, ...)
  81 {
  82         if (e->type == UCI_TYPE_SECTION)
  83         {
  84                 fprintf(stderr, "Warning: Section ");
  85                 warn_elem_section_name(uci_to_section(e), true);
  86         }
  87         else if (e->type == UCI_TYPE_OPTION)
  88         {
  89                 fprintf(stderr, "Warning: Option ");
  90                 warn_elem_section_name(uci_to_option(e)->section, false);
  91                 fprintf(stderr, ".%s ", e->name);
  92         }
  93
  94     va_list argptr;
  95     va_start(argptr, format);
  96     vfprintf(stderr, format, argptr);
  97     va_end(argptr);
  98
  99         fprintf(stderr, "\n");
 100 }
 101
 102 void
 103 warn(const char* format, ...)
 104 {
 105         fprintf(stderr, "Warning: ");
 106     va_list argptr;
 107     va_start(argptr, format);
 108     vfprintf(stderr, format, argptr);
 109     va_end(argptr);
 110         fprintf(stderr, "\n");
 111 }
 112
 113 void
 114 error(const char* format, ...)
 115 {
 116         fprintf(stderr, "Error: ");
 117     va_list argptr;
 118     va_start(argptr, format);
 119     vfprintf(stderr, format, argptr);
 120     va_end(argptr);
 121         fprintf(stderr, "\n");
 122
 123         exit(1);
 124 }
 125
 126 void
 127 info(const char* format, ...)
 128 {
 129         va_list argptr;
 130     va_start(argptr, format);
 131     vfprintf(stderr, format, argptr);
 132     va_end(argptr);
 133         fprintf(stderr, "\n");
 134 }
 135
 136 void *
 137 fw3_alloc(size_t size)
 138 {
 139         void *mem;
 140
 141         mem = calloc(1, size);
 142
 143         if (!mem)
 144                 error("Out of memory while allocating %d bytes", size);
 145
 146         return mem;
 147 }
 148
 149 char *
 150 fw3_strdup(const char *s)
 151 {
 152         char *ns;
 153
 154         ns = strdup(s);
 155
 156         if (!ns)
 157                 error("Out of memory while duplicating string '%s'", s);
 158
 159         return ns;
 160 }
 161
 162 const char *
 163 fw3_find_command(const char *cmd)
 164 {
 165         struct stat s;
 166         int plen = 0, clen = strlen(cmd) + 1;
 167         char *search, *p;
 168         static char path[PATH_MAX];
 169
 170         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 171                 return cmd;
 172
 173         search = getenv("PATH");
 174
 175         if (!search)
 176                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 177
 178         p = search;
 179
 180         do
 181         {
 182                 if (*p != ':' && *p != '\0')
 183                         continue;
 184
 185                 plen = p - search;
 186
 187                 if ((plen + clen) >= sizeof(path))
 188                         continue;
 189
 190                 strncpy(path, search, plen);
 191                 sprintf(path + plen, "/%s", cmd);
 192
 193                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 194                         return path;
 195
 196                 search = p + 1;
 197         }
 198         while (*p++);
 199
 200         return NULL;
 201 }
 202
 203 bool
 204 fw3_stdout_pipe(void)
 205 {
 206         pipe_fd = stdout;
 207         return true;
 208 }
 209
 210 bool
 211 __fw3_command_pipe(bool silent, const char *command, ...)
 212 {
 213         pid_t pid;
 214         va_list argp;
 215         int pfds[2];
 216         int argn;
 217         char *arg, **args, **tmp;
 218
 219         command = fw3_find_command(command);
 220
 221         if (!command)
 222                 return false;
 223
 224         if (pipe(pfds))
 225                 return false;
 226
 227         argn = 2;
 228         args = calloc(argn, sizeof(arg));
 229
 230         if (!args)
 231                 return false;
 232
 233         args[0] = (char *)command;
 234         args[1] = NULL;
 235
 236         va_start(argp, command);
 237
 238         while ((arg = va_arg(argp, char *)) != NULL)
 239         {
 240                 tmp = realloc(args, ++argn * sizeof(arg));
 241
 242                 if (!tmp)
 243                         break;
 244
 245                 args = tmp;
 246                 args[argn-2] = arg;
 247                 args[argn-1] = NULL;
 248         }
 249
 250         va_end(argp);
 251
 252         switch ((pid = fork()))
 253         {
 254         case -1:
 255                 return false;
 256
 257         case 0:
 258                 dup2(pfds[0], 0);
 259
 260                 close(pfds[0]);
 261                 close(pfds[1]);
 262
 263                 close(1);
 264
 265                 if (silent)
 266                         close(2);
 267
 268                 execv(command, args);
 269
 270         default:
 271                 signal(SIGPIPE, SIG_IGN);
 272                 pipe_pid = pid;
 273                 close(pfds[0]);
 274                 fcntl(pfds[1], F_SETFD, fcntl(pfds[1], F_GETFD) | FD_CLOEXEC);
 275         }
 276
 277         pipe_fd = fdopen(pfds[1], "w");
 278         return true;
 279 }
 280
 281 void
 282 fw3_pr(const char *fmt, ...)
 283 {
 284         va_list args;
 285
 286         if (fw3_pr_debug && pipe_fd != stdout)
 287         {
 288                 va_start(args, fmt);
 289                 vfprintf(stderr, fmt, args);
 290                 va_end(args);
 291         }
 292
 293         va_start(args, fmt);
 294         vfprintf(pipe_fd, fmt, args);
 295         va_end(args);
 296 }
 297
 298 void
 299 fw3_command_close(void)
 300 {
 301         if (pipe_fd && pipe_fd != stdout)
 302                 fclose(pipe_fd);
 303
 304         if (pipe_pid > -1)
 305                 waitpid(pipe_pid, NULL, 0);
 306
 307         signal(SIGPIPE, SIG_DFL);
 308
 309         pipe_fd = NULL;
 310         pipe_pid = -1;
 311 }
 312
 313 bool
 314 fw3_has_table(bool ipv6, const char *table)
 315 {
 316         FILE *f;
 317
 318         char line[12];
 319         bool seen = false;
 320
 321         const char *path = ipv6
 322                 ? "/proc/net/ip6_tables_names" : "/proc/net/ip_tables_names";
 323
 324         if (!(f = fopen(path, "r")))
 325                 return false;
 326
 327         while (fgets(line, sizeof(line), f))
 328         {
 329                 if (!strncmp(line, table, strlen(table)))
 330                 {
 331                         seen = true;
 332                         break;
 333                 }
 334         }
 335
 336         fclose(f);
 337
 338         return seen;
 339 }
 340
 341
 342 bool
 343 fw3_lock(void)
 344 {
 345         lock_fd = open(FW3_LOCKFILE, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 346
 347         if (lock_fd < 0)
 348         {
 349                 warn("Cannot create lock file %s: %s", FW3_LOCKFILE, strerror(errno));
 350                 return false;
 351         }
 352
 353         if (flock(lock_fd, LOCK_EX))
 354         {
 355                 warn("Cannot acquire exclusive lock: %s", strerror(errno));
 356                 return false;
 357         }
 358
 359         return true;
 360 }
 361
 362 void
 363 fw3_unlock(void)
 364 {
 365         if (lock_fd < 0)
 366                 return;
 367
 368         if (flock(lock_fd, LOCK_UN))
 369                 warn("Cannot release exclusive lock: %s", strerror(errno));
 370
 371         close(lock_fd);
 372         unlink(FW3_LOCKFILE);
 373
 374         lock_fd = -1;
 375 }
 376
 377
 378 static void
 379 write_defaults_uci(struct uci_context *ctx, struct fw3_defaults *d,
 380                    struct uci_package *dest)
 381 {
 382         char buf[sizeof("0xffffffff\0")];
 383         struct uci_ptr ptr = { .p = dest };
 384
 385         uci_add_section(ctx, dest, "defaults", &ptr.s);
 386
 387         ptr.o      = NULL;
 388         ptr.option = "input";
 389         ptr.value  = fw3_flag_names[d->policy_input];
 390         uci_set(ctx, &ptr);
 391
 392         ptr.o      = NULL;
 393         ptr.option = "output";
 394         ptr.value  = fw3_flag_names[d->policy_output];
 395         uci_set(ctx, &ptr);
 396
 397         ptr.o      = NULL;
 398         ptr.option = "forward";
 399         ptr.value  = fw3_flag_names[d->policy_forward];
 400         uci_set(ctx, &ptr);
 401
 402         sprintf(buf, "0x%x", d->flags[0]);
 403         ptr.o      = NULL;
 404         ptr.option = "__flags_v4";
 405         ptr.value  = buf;
 406         uci_set(ctx, &ptr);
 407
 408         sprintf(buf, "0x%x", d->flags[1]);
 409         ptr.o      = NULL;
 410         ptr.option = "__flags_v6";
 411         ptr.value  = buf;
 412         uci_set(ctx, &ptr);
 413 }
 414
 415 static void
 416 write_zone_uci(struct uci_context *ctx, struct fw3_zone *z,
 417                struct uci_package *dest, struct ifaddrs *ifaddr)
 418 {
 419         struct fw3_device *dev;
 420         struct fw3_address *sub;
 421         struct ifaddrs *ifa;
 422         enum fw3_family fam = FW3_FAMILY_ANY;
 423
 424         char *p, buf[INET6_ADDRSTRLEN];
 425
 426         struct uci_ptr ptr = { .p = dest };
 427
 428         if (!z->enabled)
 429                 return;
 430
 431         if (fw3_no_table(z->flags[0]) && !fw3_no_table(z->flags[1]))
 432                 fam = FW3_FAMILY_V6;
 433         else if (!fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 434                 fam = FW3_FAMILY_V4;
 435         else if (fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 436                 return;
 437
 438         uci_add_section(ctx, dest, "zone", &ptr.s);
 439
 440         ptr.o      = NULL;
 441         ptr.option = "name";
 442         ptr.value  = z->name;
 443         uci_set(ctx, &ptr);
 444
 445         ptr.o      = NULL;
 446         ptr.option = "input";
 447         ptr.value  = fw3_flag_names[z->policy_input];
 448         uci_set(ctx, &ptr);
 449
 450         ptr.o      = NULL;
 451         ptr.option = "output";
 452         ptr.value  = fw3_flag_names[z->policy_output];
 453         uci_set(ctx, &ptr);
 454
 455         ptr.o      = NULL;
 456         ptr.option = "forward";
 457         ptr.value  = fw3_flag_names[z->policy_forward];
 458         uci_set(ctx, &ptr);
 459
 460         ptr.o      = NULL;
 461         ptr.option = "masq";
 462         ptr.value  = z->masq ? "1" : "0";
 463         uci_set(ctx, &ptr);
 464
 465         ptr.o      = NULL;
 466         ptr.option = "mtu_fix";
 467         ptr.value  = z->mtu_fix ? "1" : "0";
 468         uci_set(ctx, &ptr);
 469
 470         ptr.o      = NULL;
 471         ptr.option = "custom_chains";
 472         ptr.value  = z->custom_chains ? "1" : "0";
 473         uci_set(ctx, &ptr);
 474
 475         if (fam != FW3_FAMILY_ANY)
 476         {
 477                 ptr.o      = NULL;
 478                 ptr.option = "family";
 479                 ptr.value  = fw3_flag_names[fam];
 480                 uci_set(ctx, &ptr);
 481         }
 482
 483         ptr.o      = NULL;
 484         ptr.option = "device";
 485
 486         fw3_foreach(dev, &z->devices)
 487         {
 488                 if (!dev)
 489                         continue;
 490
 491                 p = buf;
 492
 493                 if (dev->invert)
 494                         p += sprintf(p, "!");
 495
 496                 if (*dev->network)
 497                         p += sprintf(p, "%s@%s", dev->name, dev->network);
 498                 else
 499                         p += sprintf(p, "%s", dev->name);
 500
 501                 ptr.value = buf;
 502                 uci_add_list(ctx, &ptr);
 503         }
 504
 505         ptr.o      = NULL;
 506         ptr.option = "subnet";
 507
 508         fw3_foreach(sub, &z->subnets)
 509         {
 510                 if (!sub)
 511                         continue;
 512
 513                 ptr.value = fw3_address_to_string(sub, true, false);
 514                 uci_add_list(ctx, &ptr);
 515         }
 516
 517         ptr.o      = NULL;
 518         ptr.option = "__addrs";
 519
 520         fw3_foreach(dev, &z->devices)
 521         {
 522                 if (!dev)
 523                         continue;
 524
 525                 for (ifa = ifaddr; ifa; ifa = ifa->ifa_next)
 526                 {
 527                         if (!ifa->ifa_addr || strcmp(dev->name, ifa->ifa_name))
 528                                 continue;
 529
 530                         if (ifa->ifa_addr->sa_family == AF_INET)
 531                                 inet_ntop(AF_INET,
 532                                           &((struct sockaddr_in *)ifa->ifa_addr)->sin_addr,
 533                                           buf, sizeof(buf));
 534                         else if (ifa->ifa_addr->sa_family == AF_INET6)
 535                                 inet_ntop(AF_INET6,
 536                                           &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr,
 537                                           buf, sizeof(buf));
 538                         else
 539                                 continue;
 540
 541                         ptr.value = buf;
 542                         uci_add_list(ctx, &ptr);
 543                 }
 544         }
 545
 546         sprintf(buf, "0x%x", z->flags[0]);
 547         ptr.o      = NULL;
 548         ptr.option = "__flags_v4";
 549         ptr.value  = buf;
 550         uci_set(ctx, &ptr);
 551
 552         sprintf(buf, "0x%x", z->flags[1]);
 553         ptr.o      = NULL;
 554         ptr.option = "__flags_v6";
 555         ptr.value  = buf;
 556         uci_set(ctx, &ptr);
 557 }
 558
 559 static void
 560 write_ipset_uci(struct uci_context *ctx, struct fw3_ipset *s,
 561                 struct uci_package *dest)
 562 {
 563         struct fw3_ipset_datatype *type;
 564
 565         char buf[sizeof("65535-65535\0")];
 566
 567         struct uci_ptr ptr = { .p = dest };
 568
 569         if (!s->enabled || s->external)
 570                 return;
 571
 572         uci_add_section(ctx, dest, "ipset", &ptr.s);
 573
 574         ptr.o      = NULL;
 575         ptr.option = "name";
 576         ptr.value  = s->name;
 577         uci_set(ctx, &ptr);
 578
 579         ptr.o      = NULL;
 580         ptr.option = "storage";
 581         ptr.value  = fw3_ipset_method_names[s->method];
 582         uci_set(ctx, &ptr);
 583
 584         list_for_each_entry(type, &s->datatypes, list)
 585         {
 586                 sprintf(buf, "%s_%s", type->dir, fw3_ipset_type_names[type->type]);
 587                 ptr.o      = NULL;
 588                 ptr.option = "match";
 589                 ptr.value  = buf;
 590                 uci_add_list(ctx, &ptr);
 591         }
 592
 593         if (s->iprange.set)
 594         {
 595                 ptr.o      = NULL;
 596                 ptr.option = "iprange";
 597                 ptr.value  = fw3_address_to_string(&s->iprange, false, false);
 598                 uci_set(ctx, &ptr);
 599         }
 600
 601         if (s->portrange.set)
 602         {
 603                 sprintf(buf, "%u-%u", s->portrange.port_min, s->portrange.port_max);
 604                 ptr.o      = NULL;
 605                 ptr.option = "portrange";
 606                 ptr.value  = buf;
 607                 uci_set(ctx, &ptr);
 608         }
 609 }
 610
 611 void
 612 fw3_write_statefile(void *state)
 613 {
 614         FILE *sf;
 615         struct fw3_state *s = state;
 616         struct fw3_zone *z;
 617         struct fw3_ipset *i;
 618         struct ifaddrs *ifaddr;
 619
 620         struct uci_package *p;
 621
 622         if (fw3_no_family(s->defaults.flags[0]) &&
 623             fw3_no_family(s->defaults.flags[1]))
 624         {
 625                 unlink(FW3_STATEFILE);
 626         }
 627         else
 628         {
 629                 sf = fopen(FW3_STATEFILE, "w+");
 630
 631                 if (!sf)
 632                 {
 633                         warn("Cannot create state %s: %s", FW3_STATEFILE, strerror(errno));
 634                         return;
 635                 }
 636
 637                 if (getifaddrs(&ifaddr))
 638                 {
 639                         warn("Cannot get interface addresses: %s", strerror(errno));
 640                         ifaddr = NULL;
 641                 }
 642
 643                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 644                         uci_unload(s->uci, p);
 645
 646                 uci_import(s->uci, sf, "fw3_state", NULL, true);
 647
 648                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 649                 {
 650                         write_defaults_uci(s->uci, &s->defaults, p);
 651
 652                         list_for_each_entry(z, &s->zones, list)
 653                                 write_zone_uci(s->uci, z, p, ifaddr);
 654
 655                         list_for_each_entry(i, &s->ipsets, list)
 656                                 write_ipset_uci(s->uci, i, p);
 657
 658                         uci_export(s->uci, sf, p, true);
 659                         uci_unload(s->uci, p);
 660                 }
 661
 662                 fsync(fileno(sf));
 663                 fclose(sf);
 664
 665                 if (ifaddr)
 666                         freeifaddrs(ifaddr);
 667         }
 668 }
 669
 670
 671 void
 672 fw3_free_object(void *obj, const void *opts)
 673 {
 674         const struct fw3_option *ol;
 675         struct list_head *list, *cur, *tmp;
 676
 677         for (ol = opts; ol->name; ol++)
 678         {
 679                 if (!ol->elem_size)
 680                         continue;
 681
 682                 list = (struct list_head *)((char *)obj + ol->offset);
 683                 list_for_each_safe(cur, tmp, list)
 684                 {
 685                         list_del(cur);
 686                         free(cur);
 687                 }
 688         }
 689
 690         free(obj);
 691 }
 692
 693 void
 694 fw3_free_list(struct list_head *head)
 695 {
 696         struct list_head *entry, *tmp;
 697
 698         if (!head)
 699                 return;
 700
 701         list_for_each_safe(entry, tmp, head)
 702         {
 703                 list_del(entry);
 704                 free(entry);
 705         }
 706
 707         free(head);
 708 }
 709
 710 bool
 711 fw3_hotplug(bool add, void *zone, void *device)
 712 {
 713         struct fw3_zone *z = zone;
 714         struct fw3_device *d = device;
 715
 716         if (!*d->network)
 717                 return false;
 718
 719         switch (fork())
 720         {
 721         case -1:
 722                 warn("Unable to fork(): %s\n", strerror(errno));
 723                 return false;
 724
 725         case 0:
 726                 break;
 727
 728         default:
 729                 return true;
 730         }
 731
 732         close(0);
 733         close(1);
 734         close(2);
 735         if (chdir("/")) {};
 736
 737         clearenv();
 738         setenv("ACTION",    add ? "add" : "remove", 1);
 739         setenv("ZONE",      z->name,                1);
 740         setenv("INTERFACE", d->network,             1);
 741         setenv("DEVICE",    d->name,                1);
 742
 743         execl(FW3_HOTPLUG, FW3_HOTPLUG, "firewall", NULL);
 744
 745         /* unreached */
 746         return false;
 747 }
 748
 749 int
 750 fw3_netmask2bitlen(int family, void *mask)
 751 {
 752         int bits;
 753         struct in_addr *v4;
 754         struct in6_addr *v6;
 755
 756         if (family == FW3_FAMILY_V6)
 757                 for (bits = 0, v6 = mask;
 758                      bits < 128 && (v6->s6_addr[bits / 8] << (bits % 8)) & 128;
 759                      bits++);
 760         else
 761                 for (bits = 0, v4 = mask;
 762                      bits < 32 && (ntohl(v4->s_addr) << bits) & 0x80000000;
 763                      bits++);
 764
 765         return bits;
 766 }
 767
 768 bool
 769 fw3_bitlen2netmask(int family, int bits, void *mask)
 770 {
 771         int i;
 772         uint8_t rem, b;
 773         struct in_addr *v4;
 774         struct in6_addr *v6;
 775
 776         if (family == FW3_FAMILY_V6)
 777         {
 778                 if (bits < -128 || bits > 128)
 779                         return false;
 780
 781                 v6 = mask;
 782                 rem = abs(bits);
 783
 784                 for (i = 0; i < sizeof(v6->s6_addr); i++)
 785                 {
 786                         b = (rem > 8) ? 8 : rem;
 787                         v6->s6_addr[i] = (uint8_t)(0xFF << (8 - b));
 788                         rem -= b;
 789                 }
 790
 791                 if (bits < 0)
 792                         for (i = 0; i < sizeof(v6->s6_addr); i++)
 793                                 v6->s6_addr[i] = ~v6->s6_addr[i];
 794         }
 795         else
 796         {
 797                 if (bits < -32 || bits > 32)
 798                         return false;
 799
 800                 v4 = mask;
 801                 v4->s_addr = bits ? htonl(~((1 << (32 - abs(bits))) - 1)) : 0;
 802
 803                 if (bits < 0)
 804                         v4->s_addr = ~v4->s_addr;
 805         }
 806
 807         return true;
 808 }
 809
 810 void
 811 fw3_flush_conntrack(void *state)
 812 {
 813         bool found;
 814         struct fw3_state *s = state;
 815         struct fw3_address *addr;
 816         struct fw3_device *dev;
 817         struct fw3_zone *zone;
 818         struct ifaddrs *ifaddr, *ifa;
 819         struct sockaddr_in *sin;
 820         struct sockaddr_in6 *sin6;
 821         char buf[INET6_ADDRSTRLEN];
 822         FILE *ct;
 823
 824         if (!state)
 825         {
 826                 if ((ct = fopen("/proc/net/nf_conntrack", "w")) != NULL)
 827                 {
 828                         info(" * Flushing conntrack table ...");
 829
 830                         fwrite("f\n", 1, 2, ct);
 831                         fclose(ct);
 832                 }
 833
 834                 return;
 835         }
 836
 837         if (getifaddrs(&ifaddr))
 838         {
 839                 warn("Cannot get interface addresses: %s", strerror(errno));
 840                 return;
 841         }
 842
 843         if ((ct = fopen("/proc/net/nf_conntrack", "w")) != NULL)
 844         {
 845                 list_for_each_entry(zone, &s->zones, list)
 846                 list_for_each_entry(addr, &zone->old_addrs, list)
 847                 {
 848                         found = false;
 849
 850                         list_for_each_entry(dev, &zone->devices, list)
 851                         {
 852                                 for (ifa = ifaddr; ifa && !found; ifa = ifa->ifa_next)
 853                                 {
 854                                         if (!ifa->ifa_addr || strcmp(dev->name, ifa->ifa_name))
 855                                                 continue;
 856
 857                                         sin = (struct sockaddr_in *)ifa->ifa_addr;
 858                                         sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
 859
 860                                         if (addr->family == FW3_FAMILY_V4 &&
 861                                                 sin->sin_family == AF_INET)
 862                                         {
 863                                                 found = !memcmp(&addr->address.v4, &sin->sin_addr,
 864                                                                                 sizeof(sin->sin_addr));
 865                                         }
 866                                         else if (addr->family == FW3_FAMILY_V6 &&
 867                                                          sin6->sin6_family == AF_INET6)
 868                                         {
 869                                                 found = !memcmp(&addr->address.v6, &sin6->sin6_addr,
 870                                                                                 sizeof(sin6->sin6_addr));
 871                                         }
 872                                 }
 873
 874                                 if (found)
 875                                         break;
 876                         }
 877
 878                         if (!found)
 879                         {
 880                                 inet_ntop(addr->family == FW3_FAMILY_V4 ? AF_INET : AF_INET6,
 881                                                   &addr->address.v4, buf, sizeof(buf));
 882
 883                                 info(" * Flushing conntrack: %s", buf);
 884                                 fprintf(ct, "%s\n", buf);
 885                         }
 886                 }
 887
 888                 fclose(ct);
 889         }
 890
 891         freeifaddrs(ifaddr);
 892 }