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 = calloc(1, sizeof(*redir));
 236                 if (!redir)
 237                         continue;
 238
 239                 INIT_LIST_HEAD(&redir->proto);
 240                 INIT_LIST_HEAD(&redir->mac_src);
 241
 242                 redir->enabled = true;
 243                 redir->reflection = true;
 244
 245                 valid = false;
 246
 247                 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
 248                 {
 249                         warn_elem(e, "skipped due to invalid options");
 250                         fw3_free_redirect(redir);
 251                         continue;
 252                 }
 253
 254                 if (!redir->enabled)
 255                 {
 256                         fw3_free_redirect(redir);
 257                         continue;
 258                 }
 259
 260                 if (redir->src.invert)
 261                 {
 262                         warn_elem(e, "must not have an inverted source");
 263                         fw3_free_redirect(redir);
 264                         continue;
 265                 }
 266                 else if (redir->src.set && !redir->src.any &&
 267                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 268                 {
 269                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 270                         fw3_free_redirect(redir);
 271                         continue;
 272                 }
 273                 else if (redir->dest.set && !redir->dest.any &&
 274                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 275                 {
 276                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 277                         fw3_free_redirect(redir);
 278                         continue;
 279                 }
 280                 else if (redir->ipset.set && state->disable_ipsets)
 281                 {
 282                         warn_elem(e, "skipped due to disabled ipset support");
 283                         fw3_free_redirect(redir);
 284                         continue;
 285                 }
 286                 else if (redir->ipset.set &&
 287                          !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
 288                 {
 289                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 290                         fw3_free_redirect(redir);
 291                         continue;
 292                 }
 293
 294                 if (!check_families(e, redir))
 295                 {
 296                         fw3_free_redirect(redir);
 297                         continue;
 298                 }
 299
 300                 if (redir->target == FW3_FLAG_UNSPEC)
 301                 {
 302                         warn_elem(e, "has no target specified, defaulting to DNAT");
 303                         redir->target = FW3_FLAG_DNAT;
 304                 }
 305                 else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT)
 306                 {
 307                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 308                         redir->target = FW3_FLAG_DNAT;
 309                 }
 310
 311                 if (redir->target == FW3_FLAG_DNAT)
 312                 {
 313                         if (redir->src.any)
 314                                 warn_elem(e, "must not have source '*' for DNAT target");
 315                         else if (!redir->_src)
 316                                 warn_elem(e, "has no source specified");
 317                         else
 318                         {
 319                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 320                                 redir->_src->conntrack = true;
 321                                 valid = true;
 322                         }
 323
 324                         if (!check_local(e, redir, state) && !redir->dest.set &&
 325                             resolve_dest(e, redir, state))
 326                         {
 327                                 warn_elem(e, "does not specify a destination, assuming '%s'",
 328                                           redir->dest.name);
 329                         }
 330
 331                         if (redir->reflection && redir->_dest && redir->_src->masq)
 332                         {
 333                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 334                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 335                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 336                         }
 337                 }
 338                 else
 339                 {
 340                         if (redir->dest.any)
 341                                 warn_elem(e, "must not have destination '*' for SNAT target");
 342                         else if (!redir->_dest)
 343                                 warn_elem(e, "has no destination specified");
 344                         else if (!redir->ip_dest.set)
 345                                 warn_elem(e, "has no src_dip option specified");
 346                         else if (!list_empty(&redir->mac_src))
 347                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
 348                         else
 349                         {
 350                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 351                                 redir->_dest->conntrack = true;
 352                                 valid = true;
 353                         }
 354                 }
 355
 356                 if (list_empty(&redir->proto))
 357                 {
 358                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
 359                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
 360                 }
 361
 362                 if (!valid)
 363                 {
 364                         fw3_free_redirect(redir);
 365                         continue;
 366                 }
 367
 368                 if (!redir->port_redir.set)
 369                         redir->port_redir = redir->port_dest;
 370
 371                 list_add_tail(&redir->list, &state->redirects);
 372         }
 373 }
 374
 375 static void
 376 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 377 {
 378         if (redir->target == FW3_FLAG_DNAT)
 379                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 380         else
 381                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 382 }
 383
 384 static void
 385 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 386               struct fw3_address *addr, struct fw3_port *port)
 387 {
 388         char buf[sizeof("255.255.255.255:65535-65535\0")];
 389
 390         buf[0] = '\0';
 391
 392         if (addr && addr->set)
 393         {
 394                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 395         }
 396
 397         if (port && port->set)
 398         {
 399                 if (port->port_min == port->port_max)
 400                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 401                 else
 402                         sprintf(buf + strlen(buf), ":%u-%u",
 403                                 port->port_min, port->port_max);
 404         }
 405
 406         if (target == FW3_FLAG_DNAT)
 407         {
 408                 fw3_ipt_rule_target(r, "DNAT");
 409                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 410         }
 411         else
 412         {
 413                 fw3_ipt_rule_target(r, "SNAT");
 414                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 415         }
 416 }
 417
 418 static void
 419 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 420 {
 421         if (redir->target == FW3_FLAG_DNAT)
 422                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 423         else
 424                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 425 }
 426
 427 static void
 428 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 429 {
 430         if (name)
 431         {
 432                 if (ref)
 433                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 434                 else
 435                         fw3_ipt_rule_comment(r, name);
 436         }
 437         else
 438         {
 439                 if (ref)
 440                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 441                 else
 442                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 443         }
 444 }
 445
 446 static void
 447 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 448                struct fw3_redirect *redir, int num,
 449                struct fw3_protocol *proto, struct fw3_mac *mac)
 450 {
 451         struct fw3_ipt_rule *r;
 452         struct fw3_address *src, *dst;
 453         struct fw3_port *spt, *dpt;
 454
 455         switch (h->table)
 456         {
 457         case FW3_TABLE_NAT:
 458                 src = &redir->ip_src;
 459                 dst = &redir->ip_dest;
 460                 spt = &redir->port_src;
 461                 dpt = &redir->port_dest;
 462
 463                 if (redir->target == FW3_FLAG_SNAT)
 464                 {
 465                         dst = &redir->ip_redir;
 466                         dpt = &redir->port_redir;
 467                 }
 468
 469                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 470                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 471                 fw3_ipt_rule_mac(r, mac);
 472                 fw3_ipt_rule_ipset(r, &redir->ipset);
 473                 fw3_ipt_rule_limit(r, &redir->limit);
 474                 fw3_ipt_rule_time(r, &redir->time);
 475                 fw3_ipt_rule_mark(r, &redir->mark);
 476                 set_target_nat(r, redir);
 477                 fw3_ipt_rule_extra(r, redir->extra);
 478                 set_comment(r, redir->name, num, false);
 479                 append_chain_nat(r, redir);
 480                 break;
 481
 482         default:
 483                 break;
 484         }
 485 }
 486
 487 static void
 488 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 489                  struct fw3_redirect *redir, int num,
 490                  struct fw3_protocol *proto, struct fw3_address *ra,
 491                  struct fw3_address *ia, struct fw3_address *ea)
 492 {
 493         struct fw3_ipt_rule *r;
 494
 495         switch (h->table)
 496         {
 497         case FW3_TABLE_NAT:
 498                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 499                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 500                 fw3_ipt_rule_limit(r, &redir->limit);
 501                 fw3_ipt_rule_time(r, &redir->time);
 502                 set_comment(r, redir->name, num, true);
 503                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 504                 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
 505
 506                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 507                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 508                 fw3_ipt_rule_limit(r, &redir->limit);
 509                 fw3_ipt_rule_time(r, &redir->time);
 510                 set_comment(r, redir->name, num, true);
 511                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 512                 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
 513                 break;
 514
 515         default:
 516                 break;
 517         }
 518 }
 519
 520 static void
 521 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 522                 struct fw3_redirect *redir, int num)
 523 {
 524         struct list_head *ext_addrs, *int_addrs;
 525         struct fw3_address *ext_addr, *int_addr, ref_addr;
 526         struct fw3_protocol *proto;
 527         struct fw3_mac *mac;
 528
 529         if (redir->name)
 530                 info("   * Redirect '%s'", redir->name);
 531         else
 532                 info("   * Redirect #%u", num);
 533
 534         if (!fw3_is_family(redir->_src, handle->family) ||
 535                 !fw3_is_family(redir->_dest, handle->family))
 536         {
 537                 info("     ! Skipping due to different family of zone");
 538                 return;
 539         }
 540
 541         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 542             !fw3_is_family(&redir->ip_dest, handle->family) ||
 543                 !fw3_is_family(&redir->ip_redir, handle->family))
 544         {
 545                 if (!redir->ip_src.resolved ||
 546                     !redir->ip_dest.resolved ||
 547                     !redir->ip_redir.resolved)
 548                         info("     ! Skipping due to different family of ip address");
 549
 550                 return;
 551         }
 552
 553         if (redir->ipset.ptr)
 554         {
 555                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
 556                 {
 557                         info("     ! Skipping due to different family in ipset");
 558                         return;
 559                 }
 560
 561                 if (!fw3_check_ipset(redir->ipset.ptr))
 562                 {
 563                         info("     ! Skipping due to missing ipset '%s'",
 564                              redir->ipset.ptr->external ?
 565                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
 566                         return;
 567                 }
 568
 569                 set(redir->ipset.ptr->flags, handle->family, handle->family);
 570         }
 571
 572         fw3_foreach(proto, &redir->proto)
 573         fw3_foreach(mac, &redir->mac_src)
 574                 print_redirect(handle, state, redir, num, proto, mac);
 575
 576         /* reflection rules */
 577         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
 578                 return;
 579
 580         if (!redir->_dest || !redir->_src->masq)
 581                 return;
 582
 583         ext_addrs = fw3_resolve_zone_addresses(redir->_src);
 584         int_addrs = fw3_resolve_zone_addresses(redir->_dest);
 585
 586         if (!ext_addrs || !int_addrs)
 587                 goto out;
 588
 589         list_for_each_entry(ext_addr, ext_addrs, list)
 590         {
 591                 if (!fw3_is_family(ext_addr, handle->family))
 592                         continue;
 593
 594                 list_for_each_entry(int_addr, int_addrs, list)
 595                 {
 596                         if (!fw3_is_family(int_addr, handle->family))
 597                                 continue;
 598
 599                         fw3_foreach(proto, &redir->proto)
 600                         {
 601                                 if (!proto)
 602                                         continue;
 603
 604                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 605                                         ref_addr = *int_addr;
 606                                 else
 607                                         ref_addr = *ext_addr;
 608
 609                                 ref_addr.mask = 32;
 610                                 ext_addr->mask = 32;
 611
 612                                 print_reflection(handle, state, redir, num, proto,
 613                                                                  &ref_addr, int_addr, ext_addr);
 614                         }
 615                 }
 616         }
 617
 618 out:
 619         fw3_free_list(ext_addrs);
 620         fw3_free_list(int_addrs);
 621 }
 622
 623 void
 624 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 625 {
 626         int num = 0;
 627         struct fw3_redirect *redir;
 628
 629         if (handle->family == FW3_FAMILY_V6)
 630                 return;
 631
 632         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 633                 return;
 634
 635         list_for_each_entry(redir, &state->redirects, list)
 636                 expand_redirect(handle, state, redir, num++);
 637 }