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 static bool
 179 check_redirect(struct fw3_state *state, struct fw3_redirect *redir, struct uci_element *e)
 180 {
 181         bool valid;
 182
 183         if (!redir->enabled)
 184                 return false;
 185
 186         if (redir->src.invert)
 187         {
 188                 warn_section("redirect", redir, e, "must not have an inverted source");
 189                 return false;
 190         }
 191         else if (redir->src.set && !redir->src.any &&
 192                         !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 193         {
 194                 warn_section("redirect", redir, e, "refers to not existing zone '%s'",
 195                                 redir->src.name);
 196                 return false;
 197         }
 198         else if (redir->dest.set && !redir->dest.any &&
 199                         !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 200         {
 201                 warn_section("redirect", redir, e, "refers to not existing zone '%s'",
 202                                 redir->dest.name);
 203                 return false;
 204         }
 205         else if (redir->ipset.set && state->disable_ipsets)
 206         {
 207                 warn_section("redirect", redir, e, "skipped due to disabled ipset support",
 208                                 redir->name);
 209                 return false;
 210         }
 211         else if (redir->ipset.set &&
 212                         !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
 213         {
 214                 warn_section("redirect", redir, e, "refers to unknown ipset '%s'", redir->name,
 215                                 redir->ipset.name);
 216                 return false;
 217         }
 218
 219         if (!check_families(e, redir))
 220                 return false;
 221
 222         if (redir->target == FW3_FLAG_UNSPEC)
 223         {
 224                 warn_section("redirect", redir, e, "has no target specified, defaulting to DNAT");
 225                 redir->target = FW3_FLAG_DNAT;
 226         }
 227         else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT)
 228         {
 229                 warn_section("redirect", redir, e, "has invalid target specified, defaulting to DNAT");
 230                 redir->target = FW3_FLAG_DNAT;
 231         }
 232
 233         valid = false;
 234
 235         if (redir->target == FW3_FLAG_DNAT)
 236         {
 237                 if (redir->src.any)
 238                         warn_section("redirect", redir, e, "must not have source '*' for DNAT target");
 239                 else if (!redir->_src)
 240                         warn_section("redirect", redir, e, "has no source specified");
 241                 else
 242                 {
 243                         set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 244                         valid = true;
 245
 246                         if (!check_local(e, redir, state) && !redir->dest.set &&
 247                                         resolve_dest(e, redir, state))
 248                         {
 249                                 warn_section("redirect", redir, e,
 250                                                 "does not specify a destination, assuming '%s'",
 251                                                 redir->dest.name);
 252                         }
 253
 254                         if (redir->reflection && redir->_dest && redir->_src->masq)
 255                         {
 256                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 257                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 258                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 259                         }
 260                 }
 261         }
 262         else
 263         {
 264                 if (redir->dest.any)
 265                         warn_section("redirect", redir, e,
 266                                         "must not have destination '*' for SNAT target");
 267                 else if (!redir->_dest)
 268                         warn_section("redirect", redir, e, "has no destination specified");
 269                 else if (!redir->ip_dest.set)
 270                         warn_section("redirect", redir, e, "has no src_dip option specified");
 271                 else if (!list_empty(&redir->mac_src))
 272                         warn_section("redirect", redir, e, "must not use 'src_mac' option for SNAT target");
 273                 else
 274                 {
 275                         set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 276                         valid = true;
 277                 }
 278         }
 279
 280         if (list_empty(&redir->proto))
 281         {
 282                 warn_section("redirect", redir, e, "does not specify a protocol, assuming TCP+UDP");
 283                 fw3_parse_protocol(&redir->proto, "tcpudp", true);
 284         }
 285
 286         if (!valid)
 287                 return false;
 288
 289         if (!redir->port_redir.set)
 290                 redir->port_redir = redir->port_dest;
 291
 292         return true;
 293 }
 294
 295 static struct fw3_redirect *
 296 fw3_alloc_redirect(struct fw3_state *state)
 297 {
 298         struct fw3_redirect *redir;
 299
 300         redir = calloc(1, sizeof(*redir));
 301         if (!redir)
 302                 return NULL;
 303
 304         INIT_LIST_HEAD(&redir->proto);
 305         INIT_LIST_HEAD(&redir->mac_src);
 306
 307         redir->enabled = true;
 308         redir->reflection = true;
 309
 310         list_add_tail(&redir->list, &state->redirects);
 311
 312         return redir;
 313 }
 314
 315 void
 316 fw3_load_redirects(struct fw3_state *state, struct uci_package *p,
 317                 struct blob_attr *a)
 318 {
 319         struct uci_section *s;
 320         struct uci_element *e;
 321         struct fw3_redirect *redir;
 322         struct blob_attr *entry;
 323         unsigned rem;
 324
 325         INIT_LIST_HEAD(&state->redirects);
 326
 327         blob_for_each_attr(entry, a, rem)
 328         {
 329                 const char *type;
 330                 const char *name = "ubus redirect";
 331
 332                 if (!fw3_attr_parse_name_type(entry, &name, &type))
 333                         continue;
 334
 335                 if (strcmp(type, "redirect"))
 336                         continue;
 337
 338                 redir = fw3_alloc_redirect(state);
 339                 if (!redir)
 340                         continue;
 341
 342                 if (!fw3_parse_blob_options(redir, fw3_redirect_opts, entry, name))
 343                 {
 344                         warn_section("redirect", redir, NULL, "skipped due to invalid options");
 345                         fw3_free_redirect(redir);
 346                         continue;
 347                 }
 348
 349                 if (!check_redirect(state, redir, NULL))
 350                         fw3_free_redirect(redir);
 351         }
 352
 353         uci_foreach_element(&p->sections, e)
 354         {
 355                 s = uci_to_section(e);
 356
 357                 if (strcmp(s->type, "redirect"))
 358                         continue;
 359
 360                 redir = fw3_alloc_redirect(state);
 361                 if (!redir)
 362                         continue;
 363
 364                 if (!fw3_parse_options(redir, fw3_redirect_opts, s))
 365                 {
 366                         warn_elem(e, "skipped due to invalid options");
 367                         fw3_free_redirect(redir);
 368                         continue;
 369                 }
 370
 371                 if (!check_redirect(state, redir, e))
 372                         fw3_free_redirect(redir);
 373         }
 374 }
 375
 376 static void
 377 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 378 {
 379         if (redir->target == FW3_FLAG_DNAT)
 380                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 381         else
 382                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 383 }
 384
 385 static void
 386 set_redirect(struct fw3_ipt_rule *r, struct fw3_port *port)
 387 {
 388         char buf[sizeof("65535-65535\0")];
 389
 390         fw3_ipt_rule_target(r, "REDIRECT");
 391
 392         if (port && port->set)
 393         {
 394                 if (port->port_min == port->port_max)
 395                         sprintf(buf, "%u", port->port_min);
 396                 else
 397                         sprintf(buf, "%u-%u", port->port_min, port->port_max);
 398
 399                 fw3_ipt_rule_addarg(r, false, "--to-ports", buf);
 400         }
 401 }
 402
 403 static void
 404 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 405               struct fw3_address *addr, struct fw3_port *port)
 406 {
 407         char buf[sizeof("255.255.255.255:65535-65535\0")];
 408
 409         buf[0] = '\0';
 410
 411         if (addr && addr->set)
 412         {
 413                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 414         }
 415
 416         if (port && port->set)
 417         {
 418                 if (port->port_min == port->port_max)
 419                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 420                 else
 421                         sprintf(buf + strlen(buf), ":%u-%u",
 422                                 port->port_min, port->port_max);
 423         }
 424
 425         if (target == FW3_FLAG_DNAT)
 426         {
 427                 fw3_ipt_rule_target(r, "DNAT");
 428                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 429         }
 430         else
 431         {
 432                 fw3_ipt_rule_target(r, "SNAT");
 433                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 434         }
 435 }
 436
 437 static void
 438 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 439 {
 440         if (redir->local)
 441                 set_redirect(r, &redir->port_redir);
 442         else if (redir->target == FW3_FLAG_DNAT)
 443                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 444         else
 445                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 446 }
 447
 448 static void
 449 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 450 {
 451         if (name)
 452         {
 453                 if (ref)
 454                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 455                 else
 456                         fw3_ipt_rule_comment(r, name);
 457         }
 458         else
 459         {
 460                 if (ref)
 461                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 462                 else
 463                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 464         }
 465 }
 466
 467 static void
 468 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 469                struct fw3_redirect *redir, int num,
 470                struct fw3_protocol *proto, struct fw3_mac *mac)
 471 {
 472         struct fw3_ipt_rule *r;
 473         struct fw3_address *src, *dst;
 474         struct fw3_port *spt, *dpt;
 475
 476         switch (h->table)
 477         {
 478         case FW3_TABLE_NAT:
 479                 src = &redir->ip_src;
 480                 dst = &redir->ip_dest;
 481                 spt = &redir->port_src;
 482                 dpt = &redir->port_dest;
 483
 484                 if (redir->target == FW3_FLAG_SNAT)
 485                 {
 486                         dst = &redir->ip_redir;
 487                         dpt = &redir->port_redir;
 488                 }
 489
 490                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 491                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 492                 fw3_ipt_rule_mac(r, mac);
 493                 fw3_ipt_rule_ipset(r, &redir->ipset);
 494                 fw3_ipt_rule_limit(r, &redir->limit);
 495                 fw3_ipt_rule_time(r, &redir->time);
 496                 fw3_ipt_rule_mark(r, &redir->mark);
 497                 set_target_nat(r, redir);
 498                 fw3_ipt_rule_extra(r, redir->extra);
 499                 set_comment(r, redir->name, num, false);
 500                 append_chain_nat(r, redir);
 501                 break;
 502
 503         default:
 504                 break;
 505         }
 506 }
 507
 508 static void
 509 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 510                  struct fw3_redirect *redir, int num,
 511                  struct fw3_protocol *proto, struct fw3_address *ra,
 512                  struct fw3_address *ia, struct fw3_address *ea)
 513 {
 514         struct fw3_ipt_rule *r;
 515
 516         switch (h->table)
 517         {
 518         case FW3_TABLE_NAT:
 519                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 520                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 521                 fw3_ipt_rule_limit(r, &redir->limit);
 522                 fw3_ipt_rule_time(r, &redir->time);
 523                 set_comment(r, redir->name, num, true);
 524                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 525                 fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name);
 526
 527                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 528                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 529                 fw3_ipt_rule_limit(r, &redir->limit);
 530                 fw3_ipt_rule_time(r, &redir->time);
 531                 set_comment(r, redir->name, num, true);
 532                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 533                 fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name);
 534                 break;
 535
 536         default:
 537                 break;
 538         }
 539 }
 540
 541 static void
 542 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 543                 struct fw3_redirect *redir, int num)
 544 {
 545         struct list_head *ext_addrs, *int_addrs;
 546         struct fw3_address *ext_addr, *int_addr, ref_addr;
 547         struct fw3_protocol *proto;
 548         struct fw3_mac *mac;
 549
 550         if (redir->name)
 551                 info("   * Redirect '%s'", redir->name);
 552         else
 553                 info("   * Redirect #%u", num);
 554
 555         if (!fw3_is_family(redir->_src, handle->family) ||
 556                 !fw3_is_family(redir->_dest, handle->family))
 557         {
 558                 info("     ! Skipping due to different family of zone");
 559                 return;
 560         }
 561
 562         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 563             !fw3_is_family(&redir->ip_dest, handle->family) ||
 564                 !fw3_is_family(&redir->ip_redir, handle->family))
 565         {
 566                 if (!redir->ip_src.resolved ||
 567                     !redir->ip_dest.resolved ||
 568                     !redir->ip_redir.resolved)
 569                         info("     ! Skipping due to different family of ip address");
 570
 571                 return;
 572         }
 573
 574         if (redir->ipset.ptr)
 575         {
 576                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
 577                 {
 578                         info("     ! Skipping due to different family in ipset");
 579                         return;
 580                 }
 581
 582                 if (!fw3_check_ipset(redir->ipset.ptr))
 583                 {
 584                         info("     ! Skipping due to missing ipset '%s'",
 585                              redir->ipset.ptr->external ?
 586                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
 587                         return;
 588                 }
 589
 590                 set(redir->ipset.ptr->flags, handle->family, handle->family);
 591         }
 592
 593         fw3_foreach(proto, &redir->proto)
 594         fw3_foreach(mac, &redir->mac_src)
 595                 print_redirect(handle, state, redir, num, proto, mac);
 596
 597         /* reflection rules */
 598         if (redir->target != FW3_FLAG_DNAT || !redir->reflection || redir->local)
 599                 return;
 600
 601         if (!redir->_dest || !redir->_src->masq)
 602                 return;
 603
 604         ext_addrs = fw3_resolve_zone_addresses(redir->_src, &redir->ip_dest);
 605         int_addrs = fw3_resolve_zone_addresses(redir->_dest, NULL);
 606
 607         if (!ext_addrs || !int_addrs)
 608                 goto out;
 609
 610         list_for_each_entry(ext_addr, ext_addrs, list)
 611         {
 612                 if (!fw3_is_family(ext_addr, handle->family))
 613                         continue;
 614
 615                 list_for_each_entry(int_addr, int_addrs, list)
 616                 {
 617                         if (!fw3_is_family(int_addr, handle->family))
 618                                 continue;
 619
 620                         fw3_foreach(proto, &redir->proto)
 621                         {
 622                                 if (!proto)
 623                                         continue;
 624
 625                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 626                                         ref_addr = *int_addr;
 627                                 else
 628                                         ref_addr = *ext_addr;
 629
 630                                 ref_addr.mask.v4.s_addr = 0xFFFFFFFF;
 631                                 ext_addr->mask.v4.s_addr = 0xFFFFFFFF;
 632
 633                                 print_reflection(handle, state, redir, num, proto,
 634                                                                  &ref_addr, int_addr, ext_addr);
 635                         }
 636                 }
 637         }
 638
 639 out:
 640         fw3_free_list(ext_addrs);
 641         fw3_free_list(int_addrs);
 642 }
 643
 644 void
 645 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 646 {
 647         int num = 0;
 648         struct fw3_redirect *redir;
 649
 650         if (handle->family == FW3_FAMILY_V6)
 651                 return;
 652
 653         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 654                 return;
 655
 656         list_for_each_entry(redir, &state->redirects, list)
 657                 expand_redirect(handle, state, redir, num++);
 658 }