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