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