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         uint32_t mask;
 120
 121         if (a->family != FW3_FAMILY_V4 || b->family != FW3_FAMILY_V4)
 122                 return false;
 123
 124         mask = htonl(~((1 << (32 - a->mask)) - 1));
 125
 126         return ((a->address.v4.s_addr & mask) == (b->address.v4.s_addr & mask));
 127 }
 128
 129 static bool
 130 resolve_dest(struct uci_element *e, struct fw3_redirect *redir,
 131              struct fw3_state *state)
 132 {
 133         struct fw3_zone *zone;
 134         struct fw3_address *addr;
 135         struct list_head *addrs;
 136
 137         if (!redir->ip_redir.set)
 138                 return false;
 139
 140         list_for_each_entry(zone, &state->zones, list)
 141         {
 142                 addrs = fw3_resolve_zone_addresses(zone);
 143
 144                 if (!addrs)
 145                         continue;
 146
 147                 list_for_each_entry(addr, addrs, list)
 148                 {
 149                         if (!compare_addr(addr, &redir->ip_redir))
 150                                 continue;
 151
 152                         strncpy(redir->dest.name, zone->name, sizeof(redir->dest.name));
 153                         redir->dest.set = true;
 154                         redir->_dest = zone;
 155
 156                         break;
 157                 }
 158
 159                 fw3_free_list(addrs);
 160
 161                 if (redir->_dest)
 162                         return true;
 163         }
 164
 165         return false;
 166 }
 167
 168 static bool
 169 check_local(struct uci_element *e, struct fw3_redirect *redir,
 170             struct fw3_state *state)
 171 {
 172         struct fw3_zone *zone;
 173         struct fw3_device *net;
 174         struct fw3_address *addr, *tmp;
 175
 176         if (redir->target != FW3_FLAG_DNAT)
 177                 return false;
 178
 179         if (!redir->ip_redir.set)
 180                 redir->local = true;
 181
 182         if (redir->local)
 183                 return true;
 184
 185         list_for_each_entry(zone, &state->zones, list)
 186         {
 187                 list_for_each_entry(net, &zone->networks, list)
 188                 {
 189                         LIST_HEAD(addrs);
 190
 191                         fw3_ubus_address(&addrs, net->name);
 192                         list_for_each_entry_safe(addr, tmp, &addrs, list)
 193                         {
 194                                 if (compare_addr(&redir->ip_redir, addr)) {
 195                                         warn_elem(e, "refers to a destination address on this router, "
 196                                                      "assuming port redirection");
 197
 198                                         redir->local = true;
 199                                         continue;
 200                                 }
 201
 202                                 list_del(&addr->list);
 203                                 free(addr);
 204                         }
 205
 206                         if (redir->local)
 207                                 return true;
 208                 }
 209         }
 210
 211         return false;
 212 }
 213
 214 void
 215 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 216 {
 217         struct uci_section *s;
 218         struct uci_element *e;
 219         struct fw3_redirect *redir;
 220
 221         bool valid;
 222
 223         INIT_LIST_HEAD(&state->redirects);
 224
 225         uci_foreach_element(&p->sections, e)
 226         {
 227                 s = uci_to_section(e);
 228
 229                 if (strcmp(s->type, "redirect"))
 230                         continue;
 231
 232                 redir = calloc(1, sizeof(*redir));
 233                 if (!redir)
 234                         continue;
 235
 236                 INIT_LIST_HEAD(&redir->proto);
 237                 INIT_LIST_HEAD(&redir->mac_src);
 238
 239                 redir->enabled = true;
 240                 redir->reflection = true;
 241
 242                 valid = false;
 243
 244                 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
 245                 {
 246                         warn_elem(e, "skipped due to invalid options");
 247                         fw3_free_redirect(redir);
 248                         continue;
 249                 }
 250
 251                 if (!redir->enabled)
 252                 {
 253                         fw3_free_redirect(redir);
 254                         continue;
 255                 }
 256
 257                 if (redir->src.invert)
 258                 {
 259                         warn_elem(e, "must not have an inverted source");
 260                         fw3_free_redirect(redir);
 261                         continue;
 262                 }
 263                 else if (redir->src.set && !redir->src.any &&
 264                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 265                 {
 266                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 267                         fw3_free_redirect(redir);
 268                         continue;
 269                 }
 270                 else if (redir->dest.set && !redir->dest.any &&
 271                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 272                 {
 273                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 274                         fw3_free_redirect(redir);
 275                         continue;
 276                 }
 277                 else if (redir->ipset.set && state->disable_ipsets)
 278                 {
 279                         warn_elem(e, "skipped due to disabled ipset support");
 280                         fw3_free_redirect(redir);
 281                         continue;
 282                 }
 283                 else if (redir->ipset.set &&
 284                          !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
 285                 {
 286                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 287                         fw3_free_redirect(redir);
 288                         continue;
 289                 }
 290
 291                 if (!check_families(e, redir))
 292                 {
 293                         fw3_free_redirect(redir);
 294                         continue;
 295                 }
 296
 297                 if (redir->target == FW3_FLAG_UNSPEC)
 298                 {
 299                         warn_elem(e, "has no target specified, defaulting to DNAT");
 300                         redir->target = FW3_FLAG_DNAT;
 301                 }
 302                 else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT)
 303                 {
 304                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 305                         redir->target = FW3_FLAG_DNAT;
 306                 }
 307
 308                 if (redir->target == FW3_FLAG_DNAT)
 309                 {
 310                         if (redir->src.any)
 311                                 warn_elem(e, "must not have source '*' for DNAT target");
 312                         else if (!redir->_src)
 313                                 warn_elem(e, "has no source specified");
 314                         else
 315                         {
 316                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 317                                 redir->_src->conntrack = true;
 318                                 valid = true;
 319                         }
 320
 321                         if (!check_local(e, redir, state) && !redir->dest.set &&
 322                             resolve_dest(e, redir, state))
 323                         {
 324                                 warn_elem(e, "does not specify a destination, assuming '%s'",
 325                                           redir->dest.name);
 326                         }
 327
 328                         if (redir->reflection && redir->_dest && redir->_src->masq)
 329                         {
 330                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 331                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 332                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 333                         }
 334                 }
 335                 else
 336                 {
 337                         if (redir->dest.any)
 338                                 warn_elem(e, "must not have destination '*' for SNAT target");
 339                         else if (!redir->_dest)
 340                                 warn_elem(e, "has no destination specified");
 341                         else if (!redir->ip_dest.set)
 342                                 warn_elem(e, "has no src_dip option specified");
 343                         else if (!list_empty(&redir->mac_src))
 344                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
 345                         else
 346                         {
 347                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 348                                 redir->_dest->conntrack = true;
 349                                 valid = true;
 350                         }
 351                 }
 352
 353                 if (list_empty(&redir->proto))
 354                 {
 355                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
 356                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
 357                 }
 358
 359                 if (!valid)
 360                 {
 361                         fw3_free_redirect(redir);
 362                         continue;
 363                 }
 364
 365                 if (!redir->port_redir.set)
 366                         redir->port_redir = redir->port_dest;
 367
 368                 list_add_tail(&redir->list, &state->redirects);
 369         }
 370 }
 371
 372 static void
 373 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 374 {
 375         if (redir->target == FW3_FLAG_DNAT)
 376                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 377         else
 378                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 379 }
 380
 381 static void
 382 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 383               struct fw3_address *addr, struct fw3_port *port)
 384 {
 385         char buf[sizeof("255.255.255.255:65535-65535\0")];
 386
 387         buf[0] = '\0';
 388
 389         if (addr && addr->set)
 390         {
 391                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 392         }
 393
 394         if (port && port->set)
 395         {
 396                 if (port->port_min == port->port_max)
 397                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 398                 else
 399                         sprintf(buf + strlen(buf), ":%u-%u",
 400                                 port->port_min, port->port_max);
 401         }
 402
 403         if (target == FW3_FLAG_DNAT)
 404         {
 405                 fw3_ipt_rule_target(r, "DNAT");
 406                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 407         }
 408         else
 409         {
 410                 fw3_ipt_rule_target(r, "SNAT");
 411                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 412         }
 413 }
 414
 415 static void
 416 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 417 {
 418         if (redir->target == FW3_FLAG_DNAT)
 419                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 420         else
 421                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 422 }
 423
 424 static void
 425 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 426 {
 427         if (name)
 428         {
 429                 if (ref)
 430                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 431                 else
 432                         fw3_ipt_rule_comment(r, name);
 433         }
 434         else
 435         {
 436                 if (ref)
 437                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 438                 else
 439                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 440         }
 441 }
 442
 443 static void
 444 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 445                struct fw3_redirect *redir, int num,
 446                struct fw3_protocol *proto, struct fw3_mac *mac)
 447 {
 448         struct fw3_ipt_rule *r;
 449         struct fw3_address *src, *dst;
 450         struct fw3_port *spt, *dpt;
 451
 452         switch (h->table)
 453         {
 454         case FW3_TABLE_NAT:
 455                 src = &redir->ip_src;
 456                 dst = &redir->ip_dest;
 457                 spt = &redir->port_src;
 458                 dpt = &redir->port_dest;
 459
 460                 if (redir->target == FW3_FLAG_SNAT)
 461                 {
 462                         dst = &redir->ip_redir;
 463                         dpt = &redir->port_redir;
 464                 }
 465
 466                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 467                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 468                 fw3_ipt_rule_mac(r, mac);
 469                 fw3_ipt_rule_ipset(r, &redir->ipset);
 470                 fw3_ipt_rule_limit(r, &redir->limit);
 471                 fw3_ipt_rule_time(r, &redir->time);
 472                 fw3_ipt_rule_mark(r, &redir->mark);
 473                 set_target_nat(r, redir);
 474                 fw3_ipt_rule_extra(r, redir->extra);
 475                 set_comment(r, redir->name, num, false);
 476                 append_chain_nat(r, redir);
 477                 break;
 478
 479         default:
 480                 break;
 481         }
 482 }
 483
 484 static void
 485 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 486                  struct fw3_redirect *redir, int num,
 487                  struct fw3_protocol *proto, struct fw3_address *ra,
 488                  struct fw3_address *ia, struct fw3_address *ea)
 489 {
 490         struct fw3_ipt_rule *r;
 491
 492         switch (h->table)
 493         {
 494         case FW3_TABLE_NAT:
 495                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 496                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 497                 fw3_ipt_rule_limit(r, &redir->limit);
 498                 fw3_ipt_rule_time(r, &redir->time);
 499                 set_comment(r, redir->name, num, true);
 500                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 501                 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
 502
 503                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 504                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 505                 fw3_ipt_rule_limit(r, &redir->limit);
 506                 fw3_ipt_rule_time(r, &redir->time);
 507                 set_comment(r, redir->name, num, true);
 508                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 509                 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
 510                 break;
 511
 512         default:
 513                 break;
 514         }
 515 }
 516
 517 static void
 518 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 519                 struct fw3_redirect *redir, int num)
 520 {
 521         struct list_head *ext_addrs, *int_addrs;
 522         struct fw3_address *ext_addr, *int_addr, ref_addr;
 523         struct fw3_protocol *proto;
 524         struct fw3_mac *mac;
 525
 526         if (redir->name)
 527                 info("   * Redirect '%s'", redir->name);
 528         else
 529                 info("   * Redirect #%u", num);
 530
 531         if (!fw3_is_family(redir->_src, handle->family) ||
 532                 !fw3_is_family(redir->_dest, handle->family))
 533         {
 534                 info("     ! Skipping due to different family of zone");
 535                 return;
 536         }
 537
 538         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 539             !fw3_is_family(&redir->ip_dest, handle->family) ||
 540                 !fw3_is_family(&redir->ip_redir, handle->family))
 541         {
 542                 if (!redir->ip_src.resolved ||
 543                     !redir->ip_dest.resolved ||
 544                     !redir->ip_redir.resolved)
 545                         info("     ! Skipping due to different family of ip address");
 546
 547                 return;
 548         }
 549
 550         if (redir->ipset.ptr)
 551         {
 552                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
 553                 {
 554                         info("     ! Skipping due to different family in ipset");
 555                         return;
 556                 }
 557
 558                 if (!fw3_check_ipset(redir->ipset.ptr))
 559                 {
 560                         info("     ! Skipping due to missing ipset '%s'",
 561                              redir->ipset.ptr->external ?
 562                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
 563                         return;
 564                 }
 565
 566                 set(redir->ipset.ptr->flags, handle->family, handle->family);
 567         }
 568
 569         fw3_foreach(proto, &redir->proto)
 570         fw3_foreach(mac, &redir->mac_src)
 571                 print_redirect(handle, state, redir, num, proto, mac);
 572
 573         /* reflection rules */
 574         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
 575                 return;
 576
 577         if (!redir->_dest || !redir->_src->masq)
 578                 return;
 579
 580         ext_addrs = fw3_resolve_zone_addresses(redir->_src);
 581         int_addrs = fw3_resolve_zone_addresses(redir->_dest);
 582
 583         if (!ext_addrs || !int_addrs)
 584                 goto out;
 585
 586         list_for_each_entry(ext_addr, ext_addrs, list)
 587         {
 588                 if (!fw3_is_family(ext_addr, handle->family))
 589                         continue;
 590
 591                 list_for_each_entry(int_addr, int_addrs, list)
 592                 {
 593                         if (!fw3_is_family(int_addr, handle->family))
 594                                 continue;
 595
 596                         fw3_foreach(proto, &redir->proto)
 597                         {
 598                                 if (!proto)
 599                                         continue;
 600
 601                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 602                                         ref_addr = *int_addr;
 603                                 else
 604                                         ref_addr = *ext_addr;
 605
 606                                 ref_addr.mask = 32;
 607                                 ext_addr->mask = 32;
 608
 609                                 print_reflection(handle, state, redir, num, proto,
 610                                                                  &ref_addr, int_addr, ext_addr);
 611                         }
 612                 }
 613         }
 614
 615 out:
 616         fw3_free_list(ext_addrs);
 617         fw3_free_list(int_addrs);
 618 }
 619
 620 void
 621 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 622 {
 623         int num = 0;
 624         struct fw3_redirect *redir;
 625
 626         if (handle->family == FW3_FAMILY_V6)
 627                 return;
 628
 629         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 630                 return;
 631
 632         list_for_each_entry(redir, &state->redirects, list)
 633                 expand_redirect(handle, state, redir, num++);
 634 }