redirects.c

   1 /*
   2  * firewall3 - 3rd OpenWrt UCI firewall implementation
   3  *
   4  *   Copyright (C) 2013-2014 Jo-Philipp Wich <jow@openwrt.org>
   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 #include "redirects.h"
  20
  21
  22 const struct fw3_option fw3_redirect_opts[] = {
  23         FW3_OPT("enabled",             bool,      redirect,     enabled),
  24
  25         FW3_OPT("name",                string,    redirect,     name),
  26         FW3_OPT("family",              family,    redirect,     family),
  27
  28         FW3_OPT("src",                 device,    redirect,     src),
  29         FW3_OPT("dest",                device,    redirect,     dest),
  30
  31         FW3_OPT("ipset",               setmatch,  redirect,     ipset),
  32
  33         FW3_LIST("proto",              protocol,  redirect,     proto),
  34
  35         FW3_OPT("src_ip",              network,   redirect,     ip_src),
  36         FW3_LIST("src_mac",            mac,       redirect,     mac_src),
  37         FW3_OPT("src_port",            port,      redirect,     port_src),
  38
  39         FW3_OPT("src_dip",             network,   redirect,     ip_dest),
  40         FW3_OPT("src_dport",           port,      redirect,     port_dest),
  41
  42         FW3_OPT("dest_ip",             network,   redirect,     ip_redir),
  43         FW3_OPT("dest_port",           port,      redirect,     port_redir),
  44
  45         FW3_OPT("extra",               string,    redirect,     extra),
  46
  47         FW3_OPT("limit",               limit,     redirect,     limit),
  48         FW3_OPT("limit_burst",         int,       redirect,     limit.burst),
  49
  50         FW3_OPT("utc_time",            bool,      redirect,     time.utc),
  51         FW3_OPT("start_date",          date,      redirect,     time.datestart),
  52         FW3_OPT("stop_date",           date,      redirect,     time.datestop),
  53         FW3_OPT("start_time",          time,      redirect,     time.timestart),
  54         FW3_OPT("stop_time",           time,      redirect,     time.timestop),
  55         FW3_OPT("weekdays",            weekdays,  redirect,     time.weekdays),
  56         FW3_OPT("monthdays",           monthdays, redirect,     time.monthdays),
  57
  58         FW3_OPT("mark",                mark,      redirect,     mark),
  59
  60         FW3_OPT("reflection",          bool,      redirect,     reflection),
  61         FW3_OPT("reflection_src",      reflection_source,
  62                                                   redirect,     reflection_src),
  63
  64         FW3_OPT("target",              target,    redirect,     target),
  65
  66         { }
  67 };
  68
  69
  70 static bool
  71 check_families(struct uci_element *e, struct fw3_redirect *r)
  72 {
  73         if (r->family == FW3_FAMILY_ANY)
  74                 return true;
  75
  76         if (r->_src && r->_src->family && r->_src->family != r->family)
  77         {
  78                 warn_elem(e, "refers to source zone with different family");
  79                 return false;
  80         }
  81
  82         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  83         {
  84                 warn_elem(e, "refers to destination zone with different family");
  85                 return false;
  86         }
  87
  88         if (r->ipset.ptr && r->ipset.ptr->family &&
  89             r->ipset.ptr->family != r->family)
  90         {
  91                 warn_elem(e, "refers to ipset with different family");
  92                 return false;
  93         }
  94
  95         if (r->ip_src.family && r->ip_src.family != r->family)
  96         {
  97                 warn_elem(e, "uses source ip with different family");
  98                 return false;
  99         }
 100
 101         if (r->ip_dest.family && r->ip_dest.family != r->family)
 102         {
 103                 warn_elem(e, "uses destination ip with different family");
 104                 return false;
 105         }
 106
 107         if (r->ip_redir.family && r->ip_redir.family != r->family)
 108         {
 109                 warn_elem(e, "uses redirect ip with different family");
 110                 return false;
 111         }
 112
 113         return true;
 114 }
 115
 116 static bool
 117 compare_addr(struct fw3_address *a, struct fw3_address *b)
 118 {
 119         if (a->family != FW3_FAMILY_V4 || b->family != FW3_FAMILY_V4)
 120                 return false;
 121
 122         return ((a->address.v4.s_addr & a->mask.v4.s_addr) ==
 123                 (b->address.v4.s_addr & a->mask.v4.s_addr));
 124 }
 125
 126 static bool
 127 resolve_dest(struct uci_element *e, struct fw3_redirect *redir,
 128              struct fw3_state *state)
 129 {
 130         struct fw3_zone *zone;
 131         struct fw3_address *addr;
 132         struct list_head *addrs;
 133
 134         if (!redir->ip_redir.set)
 135                 return false;
 136
 137         list_for_each_entry(zone, &state->zones, list)
 138         {
 139                 addrs = fw3_resolve_zone_addresses(zone, NULL);
 140
 141                 if (!addrs)
 142                         continue;
 143
 144                 list_for_each_entry(addr, addrs, list)
 145                 {
 146                         if (!compare_addr(addr, &redir->ip_redir))
 147                                 continue;
 148
 149                         strncpy(redir->dest.name, zone->name, sizeof(redir->dest.name));
 150                         redir->dest.set = true;
 151                         redir->_dest = zone;
 152
 153                         break;
 154                 }
 155
 156                 fw3_free_list(addrs);
 157
 158                 if (redir->_dest)
 159                         return true;
 160         }
 161
 162         return false;
 163 }
 164
 165 static bool
 166 check_local(struct uci_element *e, struct fw3_redirect *redir,
 167             struct fw3_state *state)
 168 {
 169         struct fw3_zone *zone;
 170         struct fw3_device *net;
 171         struct fw3_address *addr, *tmp;
 172
 173         if (redir->target != FW3_FLAG_DNAT)
 174                 return false;
 175
 176         if (!redir->ip_redir.set)
 177                 redir->local = true;
 178
 179         if (redir->local)
 180                 return true;
 181
 182         list_for_each_entry(zone, &state->zones, list)
 183         {
 184                 list_for_each_entry(net, &zone->networks, list)
 185                 {
 186                         LIST_HEAD(addrs);
 187
 188                         fw3_ubus_address(&addrs, net->name);
 189                         list_for_each_entry_safe(addr, tmp, &addrs, list)
 190                         {
 191                                 if (!redir->local && compare_addr(&redir->ip_redir, addr)) {
 192                                         warn_elem(e, "refers to a destination address on this router, "
 193                                                      "assuming port redirection");
 194
 195                                         redir->local = true;
 196                                 }
 197
 198                                 list_del(&addr->list);
 199                                 free(addr);
 200                         }
 201
 202                         if (redir->local)
 203                                 return true;
 204                 }
 205         }
 206
 207         return false;
 208 }
 209
 210 void
 211 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 212 {
 213         struct uci_section *s;
 214         struct uci_element *e;
 215         struct fw3_redirect *redir;
 216
 217         bool valid;
 218
 219         INIT_LIST_HEAD(&state->redirects);
 220
 221         uci_foreach_element(&p->sections, e)
 222         {
 223                 s = uci_to_section(e);
 224
 225                 if (strcmp(s->type, "redirect"))
 226                         continue;
 227
 228                 redir = calloc(1, sizeof(*redir));
 229                 if (!redir)
 230                         continue;
 231
 232                 INIT_LIST_HEAD(&redir->proto);
 233                 INIT_LIST_HEAD(&redir->mac_src);
 234
 235                 redir->enabled = true;
 236                 redir->reflection = true;
 237
 238                 valid = false;
 239
 240                 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
 241                 {
 242                         warn_elem(e, "skipped due to invalid options");
 243                         fw3_free_redirect(redir);
 244                         continue;
 245                 }
 246
 247                 if (!redir->enabled)
 248                 {
 249                         fw3_free_redirect(redir);
 250                         continue;
 251                 }
 252
 253                 if (redir->src.invert)
 254                 {
 255                         warn_elem(e, "must not have an inverted source");
 256                         fw3_free_redirect(redir);
 257                         continue;
 258                 }
 259                 else if (redir->src.set && !redir->src.any &&
 260                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 261                 {
 262                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 263                         fw3_free_redirect(redir);
 264                         continue;
 265                 }
 266                 else if (redir->dest.set && !redir->dest.any &&
 267                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 268                 {
 269                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 270                         fw3_free_redirect(redir);
 271                         continue;
 272                 }
 273                 else if (redir->ipset.set && state->disable_ipsets)
 274                 {
 275                         warn_elem(e, "skipped due to disabled ipset support");
 276                         fw3_free_redirect(redir);
 277                         continue;
 278                 }
 279                 else if (redir->ipset.set &&
 280                          !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
 281                 {
 282                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 283                         fw3_free_redirect(redir);
 284                         continue;
 285                 }
 286
 287                 if (!check_families(e, redir))
 288                 {
 289                         fw3_free_redirect(redir);
 290                         continue;
 291                 }
 292
 293                 if (redir->target == FW3_FLAG_UNSPEC)
 294                 {
 295                         warn_elem(e, "has no target specified, defaulting to DNAT");
 296                         redir->target = FW3_FLAG_DNAT;
 297                 }
 298                 else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT)
 299                 {
 300                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 301                         redir->target = FW3_FLAG_DNAT;
 302                 }
 303
 304                 if (redir->target == FW3_FLAG_DNAT)
 305                 {
 306                         if (redir->src.any)
 307                                 warn_elem(e, "must not have source '*' for DNAT target");
 308                         else if (!redir->_src)
 309                                 warn_elem(e, "has no source specified");
 310                         else
 311                         {
 312                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 313                                 redir->_src->conntrack = true;
 314                                 valid = true;
 315                         }
 316
 317                         if (!check_local(e, redir, state) && !redir->dest.set &&
 318                             resolve_dest(e, redir, state))
 319                         {
 320                                 warn_elem(e, "does not specify a destination, assuming '%s'",
 321                                           redir->dest.name);
 322                         }
 323
 324                         if (redir->reflection && redir->_dest && redir->_src->masq)
 325                         {
 326                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 327                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 328                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 329                         }
 330                 }
 331                 else
 332                 {
 333                         if (redir->dest.any)
 334                                 warn_elem(e, "must not have destination '*' for SNAT target");
 335                         else if (!redir->_dest)
 336                                 warn_elem(e, "has no destination specified");
 337                         else if (!redir->ip_dest.set)
 338                                 warn_elem(e, "has no src_dip option specified");
 339                         else if (!list_empty(&redir->mac_src))
 340                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
 341                         else
 342                         {
 343                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 344                                 redir->_dest->conntrack = true;
 345                                 valid = true;
 346                         }
 347                 }
 348
 349                 if (list_empty(&redir->proto))
 350                 {
 351                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
 352                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
 353                 }
 354
 355                 if (!valid)
 356                 {
 357                         fw3_free_redirect(redir);
 358                         continue;
 359                 }
 360
 361                 if (!redir->port_redir.set)
 362                         redir->port_redir = redir->port_dest;
 363
 364                 list_add_tail(&redir->list, &state->redirects);
 365         }
 366 }
 367
 368 static void
 369 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 370 {
 371         if (redir->target == FW3_FLAG_DNAT)
 372                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 373         else
 374                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 375 }
 376
 377 static void
 378 set_redirect(struct fw3_ipt_rule *r, struct fw3_port *port)
 379 {
 380         char buf[sizeof("65535-65535\0")];
 381
 382         fw3_ipt_rule_target(r, "REDIRECT");
 383
 384         if (port && port->set)
 385         {
 386                 if (port->port_min == port->port_max)
 387                         sprintf(buf, "%u", port->port_min);
 388                 else
 389                         sprintf(buf, "%u-%u", port->port_min, port->port_max);
 390
 391                 fw3_ipt_rule_addarg(r, false, "--to-ports", buf);
 392         }
 393 }
 394
 395 static void
 396 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 397               struct fw3_address *addr, struct fw3_port *port)
 398 {
 399         char buf[sizeof("255.255.255.255:65535-65535\0")];
 400
 401         buf[0] = '\0';
 402
 403         if (addr && addr->set)
 404         {
 405                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 406         }
 407
 408         if (port && port->set)
 409         {
 410                 if (port->port_min == port->port_max)
 411                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 412                 else
 413                         sprintf(buf + strlen(buf), ":%u-%u",
 414                                 port->port_min, port->port_max);
 415         }
 416
 417         if (target == FW3_FLAG_DNAT)
 418         {
 419                 fw3_ipt_rule_target(r, "DNAT");
 420                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 421         }
 422         else
 423         {
 424                 fw3_ipt_rule_target(r, "SNAT");
 425                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 426         }
 427 }
 428
 429 static void
 430 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 431 {
 432         if (redir->local)
 433                 set_redirect(r, &redir->port_redir);
 434         else if (redir->target == FW3_FLAG_DNAT)
 435                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 436         else
 437                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 438 }
 439
 440 static void
 441 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 442 {
 443         if (name)
 444         {
 445                 if (ref)
 446                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 447                 else
 448                         fw3_ipt_rule_comment(r, name);
 449         }
 450         else
 451         {
 452                 if (ref)
 453                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 454                 else
 455                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 456         }
 457 }
 458
 459 static void
 460 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 461                struct fw3_redirect *redir, int num,
 462                struct fw3_protocol *proto, struct fw3_mac *mac)
 463 {
 464         struct fw3_ipt_rule *r;
 465         struct fw3_address *src, *dst;
 466         struct fw3_port *spt, *dpt;
 467
 468         switch (h->table)
 469         {
 470         case FW3_TABLE_NAT:
 471                 src = &redir->ip_src;
 472                 dst = &redir->ip_dest;
 473                 spt = &redir->port_src;
 474                 dpt = &redir->port_dest;
 475
 476                 if (redir->target == FW3_FLAG_SNAT)
 477                 {
 478                         dst = &redir->ip_redir;
 479                         dpt = &redir->port_redir;
 480                 }
 481
 482                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 483                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 484                 fw3_ipt_rule_mac(r, mac);
 485                 fw3_ipt_rule_ipset(r, &redir->ipset);
 486                 fw3_ipt_rule_limit(r, &redir->limit);
 487                 fw3_ipt_rule_time(r, &redir->time);
 488                 fw3_ipt_rule_mark(r, &redir->mark);
 489                 set_target_nat(r, redir);
 490                 fw3_ipt_rule_extra(r, redir->extra);
 491                 set_comment(r, redir->name, num, false);
 492                 append_chain_nat(r, redir);
 493                 break;
 494
 495         default:
 496                 break;
 497         }
 498 }
 499
 500 static void
 501 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 502                  struct fw3_redirect *redir, int num,
 503                  struct fw3_protocol *proto, struct fw3_address *ra,
 504                  struct fw3_address *ia, struct fw3_address *ea)
 505 {
 506         struct fw3_ipt_rule *r;
 507
 508         switch (h->table)
 509         {
 510         case FW3_TABLE_NAT:
 511                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 512                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 513                 fw3_ipt_rule_limit(r, &redir->limit);
 514                 fw3_ipt_rule_time(r, &redir->time);
 515                 set_comment(r, redir->name, num, true);
 516                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 517                 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
 518
 519                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 520                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 521                 fw3_ipt_rule_limit(r, &redir->limit);
 522                 fw3_ipt_rule_time(r, &redir->time);
 523                 set_comment(r, redir->name, num, true);
 524                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 525                 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
 526                 break;
 527
 528         default:
 529                 break;
 530         }
 531 }
 532
 533 static void
 534 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 535                 struct fw3_redirect *redir, int num)
 536 {
 537         struct list_head *ext_addrs, *int_addrs;
 538         struct fw3_address *ext_addr, *int_addr, ref_addr;
 539         struct fw3_protocol *proto;
 540         struct fw3_mac *mac;
 541
 542         if (redir->name)
 543                 info("   * Redirect '%s'", redir->name);
 544         else
 545                 info("   * Redirect #%u", num);
 546
 547         if (!fw3_is_family(redir->_src, handle->family) ||
 548                 !fw3_is_family(redir->_dest, handle->family))
 549         {
 550                 info("     ! Skipping due to different family of zone");
 551                 return;
 552         }
 553
 554         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 555             !fw3_is_family(&redir->ip_dest, handle->family) ||
 556                 !fw3_is_family(&redir->ip_redir, handle->family))
 557         {
 558                 if (!redir->ip_src.resolved ||
 559                     !redir->ip_dest.resolved ||
 560                     !redir->ip_redir.resolved)
 561                         info("     ! Skipping due to different family of ip address");
 562
 563                 return;
 564         }
 565
 566         if (redir->ipset.ptr)
 567         {
 568                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
 569                 {
 570                         info("     ! Skipping due to different family in ipset");
 571                         return;
 572                 }
 573
 574                 if (!fw3_check_ipset(redir->ipset.ptr))
 575                 {
 576                         info("     ! Skipping due to missing ipset '%s'",
 577                              redir->ipset.ptr->external ?
 578                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
 579                         return;
 580                 }
 581
 582                 set(redir->ipset.ptr->flags, handle->family, handle->family);
 583         }
 584
 585         fw3_foreach(proto, &redir->proto)
 586         fw3_foreach(mac, &redir->mac_src)
 587                 print_redirect(handle, state, redir, num, proto, mac);
 588
 589         /* reflection rules */
 590         if (redir->target != FW3_FLAG_DNAT || !redir->reflection || redir->local)
 591                 return;
 592
 593         if (!redir->_dest || !redir->_src->masq)
 594                 return;
 595
 596         ext_addrs = fw3_resolve_zone_addresses(redir->_src, &redir->ip_dest);
 597         int_addrs = fw3_resolve_zone_addresses(redir->_dest, NULL);
 598
 599         if (!ext_addrs || !int_addrs)
 600                 goto out;
 601
 602         list_for_each_entry(ext_addr, ext_addrs, list)
 603         {
 604                 if (!fw3_is_family(ext_addr, handle->family))
 605                         continue;
 606
 607                 list_for_each_entry(int_addr, int_addrs, list)
 608                 {
 609                         if (!fw3_is_family(int_addr, handle->family))
 610                                 continue;
 611
 612                         fw3_foreach(proto, &redir->proto)
 613                         {
 614                                 if (!proto)
 615                                         continue;
 616
 617                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 618                                         ref_addr = *int_addr;
 619                                 else
 620                                         ref_addr = *ext_addr;
 621
 622                                 ref_addr.mask.v4.s_addr = 0xFFFFFFFF;
 623                                 ext_addr->mask.v4.s_addr = 0xFFFFFFFF;
 624
 625                                 print_reflection(handle, state, redir, num, proto,
 626                                                                  &ref_addr, int_addr, ext_addr);
 627                         }
 628                 }
 629         }
 630
 631 out:
 632         fw3_free_list(ext_addrs);
 633         fw3_free_list(int_addrs);
 634 }
 635
 636 void
 637 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 638 {
 639         int num = 0;
 640         struct fw3_redirect *redir;
 641
 642         if (handle->family == FW3_FAMILY_V6)
 643                 return;
 644
 645         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 646                 return;
 647
 648         list_for_each_entry(redir, &state->redirects, list)
 649                 expand_redirect(handle, state, redir, num++);
 650 }