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;
 175         struct list_head *addrs;
 176
 177         if (redir->target != FW3_FLAG_DNAT)
 178                 return false;
 179
 180         if (!redir->ip_redir.set)
 181                 redir->local = true;
 182
 183         if (redir->local)
 184                 return true;
 185
 186         list_for_each_entry(zone, &state->zones, list)
 187         {
 188                 list_for_each_entry(net, &zone->networks, list)
 189                 {
 190                         addrs = fw3_ubus_address(net->name);
 191
 192                         if (!addrs)
 193                                 continue;
 194
 195                         list_for_each_entry(addr, addrs, list)
 196                         {
 197                                 if (!compare_addr(&redir->ip_redir, addr))
 198                                         continue;
 199
 200                                 warn_elem(e, "refers to a destination address on this router, "
 201                                              "assuming port redirection");
 202
 203                                 redir->local = true;
 204                                 break;
 205                         }
 206
 207                         fw3_free_list(addrs);
 208
 209                         if (redir->local)
 210                                 return true;
 211                 }
 212         }
 213
 214         return false;
 215 }
 216
 217 void
 218 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 219 {
 220         struct uci_section *s;
 221         struct uci_element *e;
 222         struct fw3_redirect *redir;
 223
 224         bool valid;
 225
 226         INIT_LIST_HEAD(&state->redirects);
 227
 228         uci_foreach_element(&p->sections, e)
 229         {
 230                 s = uci_to_section(e);
 231
 232                 if (strcmp(s->type, "redirect"))
 233                         continue;
 234
 235                 redir = malloc(sizeof(*redir));
 236
 237                 if (!redir)
 238                         continue;
 239
 240                 memset(redir, 0, sizeof(*redir));
 241
 242                 INIT_LIST_HEAD(&redir->proto);
 243                 INIT_LIST_HEAD(&redir->mac_src);
 244
 245                 redir->enabled = true;
 246                 redir->reflection = true;
 247
 248                 valid = false;
 249
 250                 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
 251                 {
 252                         warn_elem(e, "skipped due to invalid options");
 253                         fw3_free_redirect(redir);
 254                         continue;
 255                 }
 256
 257                 if (!redir->enabled)
 258                 {
 259                         fw3_free_redirect(redir);
 260                         continue;
 261                 }
 262
 263                 if (redir->src.invert)
 264                 {
 265                         warn_elem(e, "must not have an inverted source");
 266                         fw3_free_redirect(redir);
 267                         continue;
 268                 }
 269                 else if (redir->src.set && !redir->src.any &&
 270                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 271                 {
 272                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 273                         fw3_free_redirect(redir);
 274                         continue;
 275                 }
 276                 else if (redir->dest.set && !redir->dest.any &&
 277                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 278                 {
 279                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 280                         fw3_free_redirect(redir);
 281                         continue;
 282                 }
 283                 else if (redir->ipset.set && state->disable_ipsets)
 284                 {
 285                         warn_elem(e, "skipped due to disabled ipset support");
 286                         fw3_free_redirect(redir);
 287                         continue;
 288                 }
 289                 else if (redir->ipset.set &&
 290                          !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
 291                 {
 292                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 293                         fw3_free_redirect(redir);
 294                         continue;
 295                 }
 296
 297                 if (!check_families(e, redir))
 298                 {
 299                         fw3_free_redirect(redir);
 300                         continue;
 301                 }
 302
 303                 if (redir->target == FW3_FLAG_UNSPEC)
 304                 {
 305                         warn_elem(e, "has no target specified, defaulting to DNAT");
 306                         redir->target = FW3_FLAG_DNAT;
 307                 }
 308                 else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT)
 309                 {
 310                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 311                         redir->target = FW3_FLAG_DNAT;
 312                 }
 313
 314                 if (redir->target == FW3_FLAG_DNAT)
 315                 {
 316                         if (redir->src.any)
 317                                 warn_elem(e, "must not have source '*' for DNAT target");
 318                         else if (!redir->_src)
 319                                 warn_elem(e, "has no source specified");
 320                         else
 321                         {
 322                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 323                                 redir->_src->conntrack = true;
 324                                 valid = true;
 325                         }
 326
 327                         if (!check_local(e, redir, state) && !redir->dest.set &&
 328                             resolve_dest(e, redir, state))
 329                         {
 330                                 warn_elem(e, "does not specify a destination, assuming '%s'",
 331                                           redir->dest.name);
 332                         }
 333
 334                         if (redir->reflection && redir->_dest && redir->_src->masq)
 335                         {
 336                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 337                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 338                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 339                         }
 340                 }
 341                 else
 342                 {
 343                         if (redir->dest.any)
 344                                 warn_elem(e, "must not have destination '*' for SNAT target");
 345                         else if (!redir->_dest)
 346                                 warn_elem(e, "has no destination specified");
 347                         else if (!redir->ip_dest.set)
 348                                 warn_elem(e, "has no src_dip option specified");
 349                         else if (!list_empty(&redir->mac_src))
 350                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
 351                         else
 352                         {
 353                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 354                                 redir->_dest->conntrack = true;
 355                                 valid = true;
 356                         }
 357                 }
 358
 359                 if (list_empty(&redir->proto))
 360                 {
 361                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
 362                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
 363                 }
 364
 365                 if (!valid)
 366                 {
 367                         fw3_free_redirect(redir);
 368                         continue;
 369                 }
 370
 371                 if (!redir->port_redir.set)
 372                         redir->port_redir = redir->port_dest;
 373
 374                 list_add_tail(&redir->list, &state->redirects);
 375         }
 376 }
 377
 378 static void
 379 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 380 {
 381         if (redir->target == FW3_FLAG_DNAT)
 382                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 383         else
 384                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 385 }
 386
 387 static void
 388 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 389               struct fw3_address *addr, struct fw3_port *port)
 390 {
 391         char buf[sizeof("255.255.255.255:65535-65535\0")];
 392
 393         buf[0] = '\0';
 394
 395         if (addr && addr->set)
 396         {
 397                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 398         }
 399
 400         if (port && port->set)
 401         {
 402                 if (port->port_min == port->port_max)
 403                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 404                 else
 405                         sprintf(buf + strlen(buf), ":%u-%u",
 406                                 port->port_min, port->port_max);
 407         }
 408
 409         if (target == FW3_FLAG_DNAT)
 410         {
 411                 fw3_ipt_rule_target(r, "DNAT");
 412                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 413         }
 414         else
 415         {
 416                 fw3_ipt_rule_target(r, "SNAT");
 417                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 418         }
 419 }
 420
 421 static void
 422 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 423 {
 424         if (redir->target == FW3_FLAG_DNAT)
 425                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 426         else
 427                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 428 }
 429
 430 static void
 431 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 432 {
 433         if (name)
 434         {
 435                 if (ref)
 436                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 437                 else
 438                         fw3_ipt_rule_comment(r, name);
 439         }
 440         else
 441         {
 442                 if (ref)
 443                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 444                 else
 445                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 446         }
 447 }
 448
 449 static void
 450 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 451                struct fw3_redirect *redir, int num,
 452                struct fw3_protocol *proto, struct fw3_mac *mac)
 453 {
 454         struct fw3_ipt_rule *r;
 455         struct fw3_address *src, *dst;
 456         struct fw3_port *spt, *dpt;
 457
 458         switch (h->table)
 459         {
 460         case FW3_TABLE_NAT:
 461                 src = &redir->ip_src;
 462                 dst = &redir->ip_dest;
 463                 spt = &redir->port_src;
 464                 dpt = &redir->port_dest;
 465
 466                 if (redir->target == FW3_FLAG_SNAT)
 467                 {
 468                         dst = &redir->ip_redir;
 469                         dpt = &redir->port_redir;
 470                 }
 471
 472                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 473                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 474                 fw3_ipt_rule_mac(r, mac);
 475                 fw3_ipt_rule_ipset(r, &redir->ipset);
 476                 fw3_ipt_rule_limit(r, &redir->limit);
 477                 fw3_ipt_rule_time(r, &redir->time);
 478                 fw3_ipt_rule_mark(r, &redir->mark);
 479                 set_target_nat(r, redir);
 480                 fw3_ipt_rule_extra(r, redir->extra);
 481                 set_comment(r, redir->name, num, false);
 482                 append_chain_nat(r, redir);
 483                 break;
 484
 485         default:
 486                 break;
 487         }
 488 }
 489
 490 static void
 491 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 492                  struct fw3_redirect *redir, int num,
 493                  struct fw3_protocol *proto, struct fw3_address *ra,
 494                  struct fw3_address *ia, struct fw3_address *ea)
 495 {
 496         struct fw3_ipt_rule *r;
 497
 498         switch (h->table)
 499         {
 500         case FW3_TABLE_NAT:
 501                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 502                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 503                 fw3_ipt_rule_limit(r, &redir->limit);
 504                 fw3_ipt_rule_time(r, &redir->time);
 505                 set_comment(r, redir->name, num, true);
 506                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 507                 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
 508
 509                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 510                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 511                 fw3_ipt_rule_limit(r, &redir->limit);
 512                 fw3_ipt_rule_time(r, &redir->time);
 513                 set_comment(r, redir->name, num, true);
 514                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 515                 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
 516                 break;
 517
 518         default:
 519                 break;
 520         }
 521 }
 522
 523 static void
 524 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 525                 struct fw3_redirect *redir, int num)
 526 {
 527         struct list_head *ext_addrs, *int_addrs;
 528         struct fw3_address *ext_addr, *int_addr, ref_addr;
 529         struct fw3_protocol *proto;
 530         struct fw3_mac *mac;
 531
 532         if (redir->name)
 533                 info("   * Redirect '%s'", redir->name);
 534         else
 535                 info("   * Redirect #%u", num);
 536
 537         if (!fw3_is_family(redir->_src, handle->family) ||
 538                 !fw3_is_family(redir->_dest, handle->family))
 539         {
 540                 info("     ! Skipping due to different family of zone");
 541                 return;
 542         }
 543
 544         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 545             !fw3_is_family(&redir->ip_dest, handle->family) ||
 546                 !fw3_is_family(&redir->ip_redir, handle->family))
 547         {
 548                 if (!redir->ip_src.resolved ||
 549                     !redir->ip_dest.resolved ||
 550                     !redir->ip_redir.resolved)
 551                         info("     ! Skipping due to different family of ip address");
 552
 553                 return;
 554         }
 555
 556         if (redir->ipset.ptr)
 557         {
 558                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
 559                 {
 560                         info("     ! Skipping due to different family in ipset");
 561                         return;
 562                 }
 563
 564                 if (!fw3_check_ipset(redir->ipset.ptr))
 565                 {
 566                         info("     ! Skipping due to missing ipset '%s'",
 567                              redir->ipset.ptr->external ?
 568                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
 569                         return;
 570                 }
 571
 572                 set(redir->ipset.ptr->flags, handle->family, handle->family);
 573         }
 574
 575         fw3_foreach(proto, &redir->proto)
 576         fw3_foreach(mac, &redir->mac_src)
 577                 print_redirect(handle, state, redir, num, proto, mac);
 578
 579         /* reflection rules */
 580         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
 581                 return;
 582
 583         if (!redir->_dest || !redir->_src->masq)
 584                 return;
 585
 586         ext_addrs = fw3_resolve_zone_addresses(redir->_src);
 587         int_addrs = fw3_resolve_zone_addresses(redir->_dest);
 588
 589         if (!ext_addrs || !int_addrs)
 590                 goto out;
 591
 592         list_for_each_entry(ext_addr, ext_addrs, list)
 593         {
 594                 if (!fw3_is_family(ext_addr, handle->family))
 595                         continue;
 596
 597                 list_for_each_entry(int_addr, int_addrs, list)
 598                 {
 599                         if (!fw3_is_family(int_addr, handle->family))
 600                                 continue;
 601
 602                         fw3_foreach(proto, &redir->proto)
 603                         {
 604                                 if (!proto)
 605                                         continue;
 606
 607                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 608                                         ref_addr = *int_addr;
 609                                 else
 610                                         ref_addr = *ext_addr;
 611
 612                                 ref_addr.mask = 32;
 613                                 ext_addr->mask = 32;
 614
 615                                 print_reflection(handle, state, redir, num, proto,
 616                                                                  &ref_addr, int_addr, ext_addr);
 617                         }
 618                 }
 619         }
 620
 621 out:
 622         fw3_free_list(ext_addrs);
 623         fw3_free_list(int_addrs);
 624 }
 625
 626 void
 627 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 628 {
 629         int num = 0;
 630         struct fw3_redirect *redir;
 631
 632         if (handle->family == FW3_FAMILY_V6)
 633                 return;
 634
 635         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 636                 return;
 637
 638         list_for_each_entry(redir, &state->redirects, list)
 639                 expand_redirect(handle, state, redir, num++);
 640 }