redirects.c

   1 /*
   2  * firewall3 - 3rd OpenWrt UCI firewall implementation
   3  *
   4  *   Copyright (C) 2013-2014 Jo-Philipp Wich <jo@mein.io>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "redirects.h"
  20
  21
  22 const struct fw3_option fw3_redirect_opts[] = {
  23         FW3_OPT("enabled",             bool,      redirect,     enabled),
  24
  25         FW3_OPT("name",                string,    redirect,     name),
  26         FW3_OPT("family",              family,    redirect,     family),
  27
  28         FW3_OPT("src",                 device,    redirect,     src),
  29         FW3_OPT("dest",                device,    redirect,     dest),
  30
  31         FW3_OPT("ipset",               setmatch,  redirect,     ipset),
  32
  33         FW3_LIST("proto",              protocol,  redirect,     proto),
  34
  35         FW3_OPT("src_ip",              network,   redirect,     ip_src),
  36         FW3_LIST("src_mac",            mac,       redirect,     mac_src),
  37         FW3_OPT("src_port",            port,      redirect,     port_src),
  38
  39         FW3_OPT("src_dip",             network,   redirect,     ip_dest),
  40         FW3_OPT("src_dport",           port,      redirect,     port_dest),
  41
  42         FW3_OPT("dest_ip",             network,   redirect,     ip_redir),
  43         FW3_OPT("dest_port",           port,      redirect,     port_redir),
  44
  45         FW3_OPT("extra",               string,    redirect,     extra),
  46
  47         FW3_OPT("limit",               limit,     redirect,     limit),
  48         FW3_OPT("limit_burst",         int,       redirect,     limit.burst),
  49
  50         FW3_OPT("utc_time",            bool,      redirect,     time.utc),
  51         FW3_OPT("start_date",          date,      redirect,     time.datestart),
  52         FW3_OPT("stop_date",           date,      redirect,     time.datestop),
  53         FW3_OPT("start_time",          time,      redirect,     time.timestart),
  54         FW3_OPT("stop_time",           time,      redirect,     time.timestop),
  55         FW3_OPT("weekdays",            weekdays,  redirect,     time.weekdays),
  56         FW3_OPT("monthdays",           monthdays, redirect,     time.monthdays),
  57
  58         FW3_OPT("mark",                mark,      redirect,     mark),
  59
  60         FW3_OPT("reflection",          bool,      redirect,     reflection),
  61         FW3_OPT("reflection_src",      reflection_source,
  62                                                   redirect,     reflection_src),
  63
  64         FW3_OPT("target",              target,    redirect,     target),
  65
  66         { }
  67 };
  68
  69
  70 static bool
  71 check_families(struct uci_element *e, struct fw3_redirect *r)
  72 {
  73         if (r->family == FW3_FAMILY_ANY)
  74                 return true;
  75
  76         if (r->_src && r->_src->family && r->_src->family != r->family)
  77         {
  78                 warn_elem(e, "refers to source zone with different family");
  79                 return false;
  80         }
  81
  82         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  83         {
  84                 warn_elem(e, "refers to destination zone with different family");
  85                 return false;
  86         }
  87
  88         if (r->ipset.ptr && r->ipset.ptr->family &&
  89             r->ipset.ptr->family != r->family)
  90         {
  91                 warn_elem(e, "refers to ipset with different family");
  92                 return false;
  93         }
  94
  95         if (r->ip_src.family && r->ip_src.family != r->family)
  96         {
  97                 warn_elem(e, "uses source ip with different family");
  98                 return false;
  99         }
 100
 101         if (r->ip_dest.family && r->ip_dest.family != r->family)
 102         {
 103                 warn_elem(e, "uses destination ip with different family");
 104                 return false;
 105         }
 106
 107         if (r->ip_redir.family && r->ip_redir.family != r->family)
 108         {
 109                 warn_elem(e, "uses redirect ip with different family");
 110                 return false;
 111         }
 112
 113         return true;
 114 }
 115
 116 static bool
 117 compare_addr(struct fw3_address *a, struct fw3_address *b)
 118 {
 119         if (a->family != FW3_FAMILY_V4 || b->family != FW3_FAMILY_V4)
 120                 return false;
 121
 122         return ((a->address.v4.s_addr & a->mask.v4.s_addr) ==
 123                 (b->address.v4.s_addr & a->mask.v4.s_addr));
 124 }
 125
 126 static bool
 127 resolve_dest(struct uci_element *e, struct fw3_redirect *redir,
 128              struct fw3_state *state)
 129 {
 130         struct fw3_zone *zone;
 131         struct fw3_address *addr;
 132         struct list_head *addrs;
 133
 134         if (!redir->ip_redir.set)
 135                 return false;
 136
 137         list_for_each_entry(zone, &state->zones, list)
 138         {
 139                 addrs = fw3_resolve_zone_addresses(zone, NULL);
 140
 141                 if (!addrs)
 142                         continue;
 143
 144                 list_for_each_entry(addr, addrs, list)
 145                 {
 146                         if (!compare_addr(addr, &redir->ip_redir))
 147                                 continue;
 148
 149                         strncpy(redir->dest.name, zone->name, sizeof(redir->dest.name));
 150                         redir->dest.set = true;
 151                         redir->_dest = zone;
 152
 153                         break;
 154                 }
 155
 156                 fw3_free_list(addrs);
 157
 158                 if (redir->_dest)
 159                         return true;
 160         }
 161
 162         return false;
 163 }
 164
 165 static bool
 166 check_local(struct uci_element *e, struct fw3_redirect *redir,
 167             struct fw3_state *state)
 168 {
 169         if (redir->target != FW3_FLAG_DNAT)
 170                 return false;
 171
 172         if (!redir->ip_redir.set)
 173                 redir->local = true;
 174
 175         return redir->local;
 176 }
 177
 178 void
 179 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 180 {
 181         struct uci_section *s;
 182         struct uci_element *e;
 183         struct fw3_redirect *redir;
 184
 185         bool valid;
 186
 187         INIT_LIST_HEAD(&state->redirects);
 188
 189         uci_foreach_element(&p->sections, e)
 190         {
 191                 s = uci_to_section(e);
 192
 193                 if (strcmp(s->type, "redirect"))
 194                         continue;
 195
 196                 redir = calloc(1, sizeof(*redir));
 197                 if (!redir)
 198                         continue;
 199
 200                 INIT_LIST_HEAD(&redir->proto);
 201                 INIT_LIST_HEAD(&redir->mac_src);
 202
 203                 redir->enabled = true;
 204                 redir->reflection = true;
 205
 206                 valid = false;
 207
 208                 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
 209                 {
 210                         warn_elem(e, "skipped due to invalid options");
 211                         fw3_free_redirect(redir);
 212                         continue;
 213                 }
 214
 215                 if (!redir->enabled)
 216                 {
 217                         fw3_free_redirect(redir);
 218                         continue;
 219                 }
 220
 221                 if (redir->src.invert)
 222                 {
 223                         warn_elem(e, "must not have an inverted source");
 224                         fw3_free_redirect(redir);
 225                         continue;
 226                 }
 227                 else if (redir->src.set && !redir->src.any &&
 228                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 229                 {
 230                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 231                         fw3_free_redirect(redir);
 232                         continue;
 233                 }
 234                 else if (redir->dest.set && !redir->dest.any &&
 235                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 236                 {
 237                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 238                         fw3_free_redirect(redir);
 239                         continue;
 240                 }
 241                 else if (redir->ipset.set && state->disable_ipsets)
 242                 {
 243                         warn_elem(e, "skipped due to disabled ipset support");
 244                         fw3_free_redirect(redir);
 245                         continue;
 246                 }
 247                 else if (redir->ipset.set &&
 248                          !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
 249                 {
 250                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 251                         fw3_free_redirect(redir);
 252                         continue;
 253                 }
 254
 255                 if (!check_families(e, redir))
 256                 {
 257                         fw3_free_redirect(redir);
 258                         continue;
 259                 }
 260
 261                 if (redir->target == FW3_FLAG_UNSPEC)
 262                 {
 263                         warn_elem(e, "has no target specified, defaulting to DNAT");
 264                         redir->target = FW3_FLAG_DNAT;
 265                 }
 266                 else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT)
 267                 {
 268                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 269                         redir->target = FW3_FLAG_DNAT;
 270                 }
 271
 272                 if (redir->target == FW3_FLAG_DNAT)
 273                 {
 274                         if (redir->src.any)
 275                                 warn_elem(e, "must not have source '*' for DNAT target");
 276                         else if (!redir->_src)
 277                                 warn_elem(e, "has no source specified");
 278                         else
 279                         {
 280                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 281                                 valid = true;
 282
 283                                 if (!check_local(e, redir, state) && !redir->dest.set &&
 284                                     resolve_dest(e, redir, state))
 285                                 {
 286                                         warn_elem(e, "does not specify a destination, assuming '%s'",
 287                                                   redir->dest.name);
 288                                 }
 289
 290                                 if (redir->reflection && redir->_dest && redir->_src->masq)
 291                                 {
 292                                         set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 293                                         set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 294                                         set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 295                                 }
 296                         }
 297                 }
 298                 else
 299                 {
 300                         if (redir->dest.any)
 301                                 warn_elem(e, "must not have destination '*' for SNAT target");
 302                         else if (!redir->_dest)
 303                                 warn_elem(e, "has no destination specified");
 304                         else if (!redir->ip_dest.set)
 305                                 warn_elem(e, "has no src_dip option specified");
 306                         else if (!list_empty(&redir->mac_src))
 307                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
 308                         else
 309                         {
 310                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 311                                 valid = true;
 312                         }
 313                 }
 314
 315                 if (list_empty(&redir->proto))
 316                 {
 317                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
 318                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
 319                 }
 320
 321                 if (!valid)
 322                 {
 323                         fw3_free_redirect(redir);
 324                         continue;
 325                 }
 326
 327                 if (!redir->port_redir.set)
 328                         redir->port_redir = redir->port_dest;
 329
 330                 list_add_tail(&redir->list, &state->redirects);
 331         }
 332 }
 333
 334 static void
 335 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 336 {
 337         if (redir->target == FW3_FLAG_DNAT)
 338                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 339         else
 340                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 341 }
 342
 343 static void
 344 set_redirect(struct fw3_ipt_rule *r, struct fw3_port *port)
 345 {
 346         char buf[sizeof("65535-65535\0")];
 347
 348         fw3_ipt_rule_target(r, "REDIRECT");
 349
 350         if (port && port->set)
 351         {
 352                 if (port->port_min == port->port_max)
 353                         sprintf(buf, "%u", port->port_min);
 354                 else
 355                         sprintf(buf, "%u-%u", port->port_min, port->port_max);
 356
 357                 fw3_ipt_rule_addarg(r, false, "--to-ports", buf);
 358         }
 359 }
 360
 361 static void
 362 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 363               struct fw3_address *addr, struct fw3_port *port)
 364 {
 365         char buf[sizeof("255.255.255.255:65535-65535\0")];
 366
 367         buf[0] = '\0';
 368
 369         if (addr && addr->set)
 370         {
 371                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 372         }
 373
 374         if (port && port->set)
 375         {
 376                 if (port->port_min == port->port_max)
 377                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 378                 else
 379                         sprintf(buf + strlen(buf), ":%u-%u",
 380                                 port->port_min, port->port_max);
 381         }
 382
 383         if (target == FW3_FLAG_DNAT)
 384         {
 385                 fw3_ipt_rule_target(r, "DNAT");
 386                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 387         }
 388         else
 389         {
 390                 fw3_ipt_rule_target(r, "SNAT");
 391                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 392         }
 393 }
 394
 395 static void
 396 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 397 {
 398         if (redir->local)
 399                 set_redirect(r, &redir->port_redir);
 400         else if (redir->target == FW3_FLAG_DNAT)
 401                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 402         else
 403                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 404 }
 405
 406 static void
 407 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 408 {
 409         if (name)
 410         {
 411                 if (ref)
 412                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 413                 else
 414                         fw3_ipt_rule_comment(r, name);
 415         }
 416         else
 417         {
 418                 if (ref)
 419                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 420                 else
 421                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 422         }
 423 }
 424
 425 static void
 426 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 427                struct fw3_redirect *redir, int num,
 428                struct fw3_protocol *proto, struct fw3_mac *mac)
 429 {
 430         struct fw3_ipt_rule *r;
 431         struct fw3_address *src, *dst;
 432         struct fw3_port *spt, *dpt;
 433
 434         switch (h->table)
 435         {
 436         case FW3_TABLE_NAT:
 437                 src = &redir->ip_src;
 438                 dst = &redir->ip_dest;
 439                 spt = &redir->port_src;
 440                 dpt = &redir->port_dest;
 441
 442                 if (redir->target == FW3_FLAG_SNAT)
 443                 {
 444                         dst = &redir->ip_redir;
 445                         dpt = &redir->port_redir;
 446                 }
 447
 448                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 449                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 450                 fw3_ipt_rule_mac(r, mac);
 451                 fw3_ipt_rule_ipset(r, &redir->ipset);
 452                 fw3_ipt_rule_limit(r, &redir->limit);
 453                 fw3_ipt_rule_time(r, &redir->time);
 454                 fw3_ipt_rule_mark(r, &redir->mark);
 455                 set_target_nat(r, redir);
 456                 fw3_ipt_rule_extra(r, redir->extra);
 457                 set_comment(r, redir->name, num, false);
 458                 append_chain_nat(r, redir);
 459                 break;
 460
 461         default:
 462                 break;
 463         }
 464 }
 465
 466 static void
 467 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 468                  struct fw3_redirect *redir, int num,
 469                  struct fw3_protocol *proto, struct fw3_address *ra,
 470                  struct fw3_address *ia, struct fw3_address *ea)
 471 {
 472         struct fw3_ipt_rule *r;
 473
 474         switch (h->table)
 475         {
 476         case FW3_TABLE_NAT:
 477                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 478                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 479                 fw3_ipt_rule_limit(r, &redir->limit);
 480                 fw3_ipt_rule_time(r, &redir->time);
 481                 set_comment(r, redir->name, num, true);
 482                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 483                 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
 484
 485                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 486                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 487                 fw3_ipt_rule_limit(r, &redir->limit);
 488                 fw3_ipt_rule_time(r, &redir->time);
 489                 set_comment(r, redir->name, num, true);
 490                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 491                 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
 492                 break;
 493
 494         default:
 495                 break;
 496         }
 497 }
 498
 499 static void
 500 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 501                 struct fw3_redirect *redir, int num)
 502 {
 503         struct list_head *ext_addrs, *int_addrs;
 504         struct fw3_address *ext_addr, *int_addr, ref_addr;
 505         struct fw3_protocol *proto;
 506         struct fw3_mac *mac;
 507
 508         if (redir->name)
 509                 info("   * Redirect '%s'", redir->name);
 510         else
 511                 info("   * Redirect #%u", num);
 512
 513         if (!fw3_is_family(redir->_src, handle->family) ||
 514                 !fw3_is_family(redir->_dest, handle->family))
 515         {
 516                 info("     ! Skipping due to different family of zone");
 517                 return;
 518         }
 519
 520         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 521             !fw3_is_family(&redir->ip_dest, handle->family) ||
 522                 !fw3_is_family(&redir->ip_redir, handle->family))
 523         {
 524                 if (!redir->ip_src.resolved ||
 525                     !redir->ip_dest.resolved ||
 526                     !redir->ip_redir.resolved)
 527                         info("     ! Skipping due to different family of ip address");
 528
 529                 return;
 530         }
 531
 532         if (redir->ipset.ptr)
 533         {
 534                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
 535                 {
 536                         info("     ! Skipping due to different family in ipset");
 537                         return;
 538                 }
 539
 540                 if (!fw3_check_ipset(redir->ipset.ptr))
 541                 {
 542                         info("     ! Skipping due to missing ipset '%s'",
 543                              redir->ipset.ptr->external ?
 544                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
 545                         return;
 546                 }
 547
 548                 set(redir->ipset.ptr->flags, handle->family, handle->family);
 549         }
 550
 551         fw3_foreach(proto, &redir->proto)
 552         fw3_foreach(mac, &redir->mac_src)
 553                 print_redirect(handle, state, redir, num, proto, mac);
 554
 555         /* reflection rules */
 556         if (redir->target != FW3_FLAG_DNAT || !redir->reflection || redir->local)
 557                 return;
 558
 559         if (!redir->_dest || !redir->_src->masq)
 560                 return;
 561
 562         ext_addrs = fw3_resolve_zone_addresses(redir->_src, &redir->ip_dest);
 563         int_addrs = fw3_resolve_zone_addresses(redir->_dest, NULL);
 564
 565         if (!ext_addrs || !int_addrs)
 566                 goto out;
 567
 568         list_for_each_entry(ext_addr, ext_addrs, list)
 569         {
 570                 if (!fw3_is_family(ext_addr, handle->family))
 571                         continue;
 572
 573                 list_for_each_entry(int_addr, int_addrs, list)
 574                 {
 575                         if (!fw3_is_family(int_addr, handle->family))
 576                                 continue;
 577
 578                         fw3_foreach(proto, &redir->proto)
 579                         {
 580                                 if (!proto)
 581                                         continue;
 582
 583                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 584                                         ref_addr = *int_addr;
 585                                 else
 586                                         ref_addr = *ext_addr;
 587
 588                                 ref_addr.mask.v4.s_addr = 0xFFFFFFFF;
 589                                 ext_addr->mask.v4.s_addr = 0xFFFFFFFF;
 590
 591                                 print_reflection(handle, state, redir, num, proto,
 592                                                                  &ref_addr, int_addr, ext_addr);
 593                         }
 594                 }
 595         }
 596
 597 out:
 598         fw3_free_list(ext_addrs);
 599         fw3_free_list(int_addrs);
 600 }
 601
 602 void
 603 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 604 {
 605         int num = 0;
 606         struct fw3_redirect *redir;
 607
 608         if (handle->family == FW3_FAMILY_V6)
 609                 return;
 610
 611         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 612                 return;
 613
 614         list_for_each_entry(redir, &state->redirects, list)
 615                 expand_redirect(handle, state, redir, num++);
 616 }