redirects.c

   1 /*
   2  * firewall3 - 3rd OpenWrt UCI firewall implementation
   3  *
   4  *   Copyright (C) 2013 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("utc_time",            bool,      redirect,     time.utc),
  48         FW3_OPT("start_date",          date,      redirect,     time.datestart),
  49         FW3_OPT("stop_date",           date,      redirect,     time.datestop),
  50         FW3_OPT("start_time",          time,      redirect,     time.timestart),
  51         FW3_OPT("stop_time",           time,      redirect,     time.timestop),
  52         FW3_OPT("weekdays",            weekdays,  redirect,     time.weekdays),
  53         FW3_OPT("monthdays",           monthdays, redirect,     time.monthdays),
  54
  55         FW3_OPT("mark",                mark,      redirect,     mark),
  56
  57         FW3_OPT("reflection",          bool,      redirect,     reflection),
  58         FW3_OPT("reflection_src",      reflection_source,
  59                                                   redirect,     reflection_src),
  60
  61         FW3_OPT("target",              target,    redirect,     target),
  62
  63         { }
  64 };
  65
  66
  67 static bool
  68 check_families(struct uci_element *e, struct fw3_redirect *r)
  69 {
  70         if (r->family == FW3_FAMILY_ANY)
  71                 return true;
  72
  73         if (r->_src && r->_src->family && r->_src->family != r->family)
  74         {
  75                 warn_elem(e, "refers to source zone with different family");
  76                 return false;
  77         }
  78
  79         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  80         {
  81                 warn_elem(e, "refers to destination zone with different family");
  82                 return false;
  83         }
  84
  85         if (r->ipset.ptr && r->ipset.ptr->family &&
  86             r->ipset.ptr->family != r->family)
  87         {
  88                 warn_elem(e, "refers to ipset with different family");
  89                 return false;
  90         }
  91
  92         if (r->ip_src.family && r->ip_src.family != r->family)
  93         {
  94                 warn_elem(e, "uses source ip with different family");
  95                 return false;
  96         }
  97
  98         if (r->ip_dest.family && r->ip_dest.family != r->family)
  99         {
 100                 warn_elem(e, "uses destination ip with different family");
 101                 return false;
 102         }
 103
 104         if (r->ip_redir.family && r->ip_redir.family != r->family)
 105         {
 106                 warn_elem(e, "uses redirect ip with different family");
 107                 return false;
 108         }
 109
 110         return true;
 111 }
 112
 113 static bool
 114 compare_addr(struct fw3_address *a, struct fw3_address *b)
 115 {
 116         uint32_t mask;
 117
 118         if (a->family != FW3_FAMILY_V4)
 119                 return false;
 120
 121         mask = ~((1 << (32 - a->mask)) - 1);
 122
 123         return ((a->address.v4.s_addr & mask) == (b->address.v4.s_addr & mask));
 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 void
 166 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 167 {
 168         struct uci_section *s;
 169         struct uci_element *e;
 170         struct fw3_redirect *redir;
 171
 172         bool valid;
 173
 174         INIT_LIST_HEAD(&state->redirects);
 175
 176         uci_foreach_element(&p->sections, e)
 177         {
 178                 s = uci_to_section(e);
 179
 180                 if (strcmp(s->type, "redirect"))
 181                         continue;
 182
 183                 redir = malloc(sizeof(*redir));
 184
 185                 if (!redir)
 186                         continue;
 187
 188                 memset(redir, 0, sizeof(*redir));
 189
 190                 INIT_LIST_HEAD(&redir->proto);
 191                 INIT_LIST_HEAD(&redir->mac_src);
 192
 193                 redir->enabled = true;
 194                 redir->reflection = true;
 195
 196                 valid = false;
 197
 198                 fw3_parse_options(redir, fw3_redirect_opts, s);
 199
 200                 if (!redir->enabled)
 201                 {
 202                         fw3_free_redirect(redir);
 203                         continue;
 204                 }
 205
 206                 if (redir->src.invert)
 207                 {
 208                         warn_elem(e, "must not have an inverted source");
 209                         fw3_free_redirect(redir);
 210                         continue;
 211                 }
 212                 else if (redir->src.set && !redir->src.any &&
 213                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 214                 {
 215                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 216                         fw3_free_redirect(redir);
 217                         continue;
 218                 }
 219                 else if (redir->dest.set && !redir->dest.any &&
 220                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 221                 {
 222                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 223                         fw3_free_redirect(redir);
 224                         continue;
 225                 }
 226                 else if (redir->ipset.set && state->disable_ipsets)
 227                 {
 228                         warn_elem(e, "skipped due to disabled ipset support");
 229                         fw3_free_redirect(redir);
 230                         continue;
 231                 }
 232                 else if (redir->ipset.set &&
 233                          !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name)))
 234                 {
 235                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 236                         fw3_free_redirect(redir);
 237                         continue;
 238                 }
 239
 240                 if (!check_families(e, redir))
 241                 {
 242                         fw3_free_redirect(redir);
 243                         continue;
 244                 }
 245
 246                 if (redir->target == FW3_FLAG_UNSPEC)
 247                 {
 248                         warn_elem(e, "has no target specified, defaulting to DNAT");
 249                         redir->target = FW3_FLAG_DNAT;
 250                 }
 251                 else if (redir->target < FW3_FLAG_DNAT)
 252                 {
 253                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 254                         redir->target = FW3_FLAG_DNAT;
 255                 }
 256
 257                 if (redir->target == FW3_FLAG_DNAT)
 258                 {
 259                         if (redir->src.any)
 260                                 warn_elem(e, "must not have source '*' for DNAT target");
 261                         else if (!redir->_src)
 262                                 warn_elem(e, "has no source specified");
 263                         else
 264                         {
 265                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 266                                 redir->_src->conntrack = true;
 267                                 valid = true;
 268                         }
 269
 270                         if (!redir->dest.set && resolve_dest(e, redir, state))
 271                         {
 272                                 warn_elem(e, "does not specify a destination, assuming '%s'",
 273                                           redir->dest.name);
 274                         }
 275
 276                         if (redir->reflection && redir->_dest && redir->_src->masq)
 277                         {
 278                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 279                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 280                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 281                         }
 282                 }
 283                 else
 284                 {
 285                         if (redir->dest.any)
 286                                 warn_elem(e, "must not have destination '*' for SNAT target");
 287                         else if (!redir->_dest)
 288                                 warn_elem(e, "has no destination specified");
 289                         else if (!redir->ip_dest.set)
 290                                 warn_elem(e, "has no src_dip option specified");
 291                         else if (!list_empty(&redir->mac_src))
 292                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
 293                         else
 294                         {
 295                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 296                                 redir->_dest->conntrack = true;
 297                                 valid = true;
 298                         }
 299                 }
 300
 301                 if (list_empty(&redir->proto))
 302                 {
 303                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
 304                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
 305                 }
 306
 307                 if (!valid)
 308                 {
 309                         fw3_free_redirect(redir);
 310                         continue;
 311                 }
 312
 313                 if (!redir->port_redir.set)
 314                         redir->port_redir = redir->port_dest;
 315
 316                 list_add_tail(&redir->list, &state->redirects);
 317         }
 318 }
 319
 320 static void
 321 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 322 {
 323         if (redir->target == FW3_FLAG_DNAT)
 324                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 325         else
 326                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 327 }
 328
 329 static void
 330 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 331               struct fw3_address *addr, struct fw3_port *port)
 332 {
 333         char buf[sizeof("255.255.255.255:65535-65535\0")];
 334
 335         buf[0] = '\0';
 336
 337         if (addr && addr->set)
 338         {
 339                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 340         }
 341
 342         if (port && port->set)
 343         {
 344                 if (port->port_min == port->port_max)
 345                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 346                 else
 347                         sprintf(buf + strlen(buf), ":%u-%u",
 348                                 port->port_min, port->port_max);
 349         }
 350
 351         if (target == FW3_FLAG_DNAT)
 352         {
 353                 fw3_ipt_rule_target(r, "DNAT");
 354                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 355         }
 356         else
 357         {
 358                 fw3_ipt_rule_target(r, "SNAT");
 359                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 360         }
 361 }
 362
 363 static void
 364 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 365 {
 366         if (redir->target == FW3_FLAG_DNAT)
 367                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 368         else
 369                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 370 }
 371
 372 static void
 373 append_chain_filter(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 374 {
 375         if (redir->target == FW3_FLAG_DNAT)
 376         {
 377                 /* XXX: check for local ip */
 378                 if (!redir->ip_redir.set)
 379                         fw3_ipt_rule_append(r, "zone_%s_input", redir->src.name);
 380                 else
 381                         fw3_ipt_rule_append(r, "zone_%s_forward", redir->src.name);
 382         }
 383         else
 384         {
 385                 if (redir->src.set && !redir->src.any)
 386                         fw3_ipt_rule_append(r, "zone_%s_forward", redir->src.name);
 387                 else
 388                         fw3_ipt_rule_append(r, "delegate_forward");
 389         }
 390 }
 391
 392 static void
 393 set_target_filter(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 394 {
 395         /* XXX: check for local ip */
 396         if (redir->target == FW3_FLAG_DNAT && !redir->ip_redir.set)
 397                 fw3_ipt_rule_extra(r, "-m conntrack --ctstate DNAT");
 398
 399         fw3_ipt_rule_target(r, "ACCEPT");
 400 }
 401
 402 static void
 403 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 404 {
 405         if (name)
 406         {
 407                 if (ref)
 408                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 409                 else
 410                         fw3_ipt_rule_comment(r, name);
 411         }
 412         else
 413         {
 414                 if (ref)
 415                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 416                 else
 417                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 418         }
 419 }
 420
 421 static void
 422 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 423                struct fw3_redirect *redir, int num,
 424                struct fw3_protocol *proto, struct fw3_mac *mac)
 425 {
 426         struct fw3_ipt_rule *r;
 427         struct fw3_address *src, *dst;
 428         struct fw3_port *spt, *dpt;
 429
 430         switch (h->table)
 431         {
 432         case FW3_TABLE_NAT:
 433                 src = &redir->ip_src;
 434                 dst = &redir->ip_dest;
 435                 spt = &redir->port_src;
 436                 dpt = &redir->port_dest;
 437
 438                 if (redir->target == FW3_FLAG_SNAT)
 439                 {
 440                         dst = &redir->ip_redir;
 441                         dpt = &redir->port_redir;
 442                 }
 443
 444                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 445                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 446                 fw3_ipt_rule_mac(r, mac);
 447                 fw3_ipt_rule_ipset(r, &redir->ipset);
 448                 fw3_ipt_rule_time(r, &redir->time);
 449                 fw3_ipt_rule_mark(r, &redir->mark);
 450                 set_target_nat(r, redir);
 451                 fw3_ipt_rule_extra(r, redir->extra);
 452                 set_comment(r, redir->name, num, false);
 453                 append_chain_nat(r, redir);
 454                 break;
 455
 456         case FW3_TABLE_FILTER:
 457                 src = &redir->ip_src;
 458                 dst = &redir->ip_redir;
 459                 spt = &redir->port_src;
 460                 dpt = &redir->port_redir;
 461
 462                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 463                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 464                 fw3_ipt_rule_mac(r, mac);
 465                 fw3_ipt_rule_ipset(r, &redir->ipset);
 466                 fw3_ipt_rule_time(r, &redir->time);
 467                 fw3_ipt_rule_mark(r, &redir->mark);
 468                 set_target_filter(r, redir);
 469                 fw3_ipt_rule_extra(r, redir->extra);
 470                 set_comment(r, redir->name, num, false);
 471                 append_chain_filter(r, redir);
 472                 break;
 473
 474         default:
 475                 break;
 476         }
 477 }
 478
 479 static void
 480 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 481                  struct fw3_redirect *redir, int num,
 482                  struct fw3_protocol *proto, struct fw3_address *ra,
 483                  struct fw3_address *ia, struct fw3_address *ea)
 484 {
 485         struct fw3_ipt_rule *r;
 486
 487         switch (h->table)
 488         {
 489         case FW3_TABLE_NAT:
 490                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 491                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 492                 fw3_ipt_rule_time(r, &redir->time);
 493                 set_comment(r, redir->name, num, true);
 494                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 495                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->dest.name);
 496
 497                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 498                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 499                 fw3_ipt_rule_time(r, &redir->time);
 500                 set_comment(r, redir->name, num, true);
 501                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 502                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 503                 break;
 504
 505         case FW3_TABLE_FILTER:
 506                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 507                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 508                 fw3_ipt_rule_time(r, &redir->time);
 509                 set_comment(r, redir->name, num, true);
 510                 fw3_ipt_rule_target(r, "zone_%s_dest_ACCEPT", redir->dest.name);
 511                 fw3_ipt_rule_append(r, "zone_%s_forward", redir->dest.name);
 512                 break;
 513
 514         default:
 515                 break;
 516         }
 517 }
 518
 519 static void
 520 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 521                 struct fw3_redirect *redir, int num)
 522 {
 523         struct list_head *ext_addrs, *int_addrs;
 524         struct fw3_address *ext_addr, *int_addr, ref_addr;
 525         struct fw3_protocol *proto;
 526         struct fw3_mac *mac;
 527
 528         if (redir->name)
 529                 info("   * Redirect '%s'", redir->name);
 530         else
 531                 info("   * Redirect #%u", num);
 532
 533         if (!fw3_is_family(redir->_src, handle->family) ||
 534                 !fw3_is_family(redir->_dest, handle->family))
 535         {
 536                 info("     ! Skipping due to different family of zone");
 537                 return;
 538         }
 539
 540         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 541             !fw3_is_family(&redir->ip_dest, handle->family) ||
 542                 !fw3_is_family(&redir->ip_redir, handle->family))
 543         {
 544                 if (!redir->ip_src.resolved ||
 545                     !redir->ip_dest.resolved ||
 546                     !redir->ip_redir.resolved)
 547                         info("     ! Skipping due to different family of ip address");
 548
 549                 return;
 550         }
 551
 552         if (redir->ipset.ptr)
 553         {
 554                 if (!fw3_is_family(redir->ipset.ptr, handle->family))
 555                 {
 556                         info("     ! Skipping due to different family in ipset");
 557                         return;
 558                 }
 559
 560                 if (!fw3_check_ipset(redir->ipset.ptr))
 561                 {
 562                         info("     ! Skipping due to missing ipset '%s'",
 563                              redir->ipset.ptr->external ?
 564                                         redir->ipset.ptr->external : redir->ipset.ptr->name);
 565                         return;
 566                 }
 567
 568                 set(redir->ipset.ptr->flags, handle->family, handle->family);
 569         }
 570
 571         fw3_foreach(proto, &redir->proto)
 572         fw3_foreach(mac, &redir->mac_src)
 573                 print_redirect(handle, state, redir, num, proto, mac);
 574
 575         /* reflection rules */
 576         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
 577                 return;
 578
 579         if (!redir->_dest || !redir->_src->masq)
 580                 return;
 581
 582         ext_addrs = fw3_resolve_zone_addresses(redir->_src);
 583         int_addrs = fw3_resolve_zone_addresses(redir->_dest);
 584
 585         if (!ext_addrs || !int_addrs)
 586                 goto out;
 587
 588         list_for_each_entry(ext_addr, ext_addrs, list)
 589         {
 590                 if (!fw3_is_family(ext_addr, handle->family))
 591                         continue;
 592
 593                 list_for_each_entry(int_addr, int_addrs, list)
 594                 {
 595                         if (!fw3_is_family(int_addr, handle->family))
 596                                 continue;
 597
 598                         fw3_foreach(proto, &redir->proto)
 599                         {
 600                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 601                                         continue;
 602
 603                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 604                                         ref_addr = *int_addr;
 605                                 else
 606                                         ref_addr = *ext_addr;
 607
 608                                 ref_addr.mask = 32;
 609                                 ext_addr->mask = 32;
 610
 611                                 print_reflection(handle, state, redir, num, proto,
 612                                                                  &ref_addr, int_addr, ext_addr);
 613                         }
 614                 }
 615         }
 616
 617 out:
 618         fw3_free_list(ext_addrs);
 619         fw3_free_list(int_addrs);
 620 }
 621
 622 void
 623 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 624 {
 625         int num = 0;
 626         struct fw3_redirect *redir;
 627
 628         if (handle->family == FW3_FAMILY_V6)
 629                 return;
 630
 631         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 632                 return;
 633
 634         list_for_each_entry(redir, &state->redirects, list)
 635                 expand_redirect(handle, state, redir, num++);
 636 }