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",               device,    redirect,     ipset),
  32
  33         FW3_LIST("proto",              protocol,  redirect,     proto),
  34
  35         FW3_OPT("src_ip",              address,   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",             address,   redirect,     ip_dest),
  40         FW3_OPT("src_dport",           port,      redirect,     port_dest),
  41
  42         FW3_OPT("dest_ip",             address,   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 && r->_ipset->family && r->_ipset->family != r->family)
  86         {
  87                 warn_elem(e, "refers to ipset with different family");
  88                 return false;
  89         }
  90
  91         if (r->ip_src.family && r->ip_src.family != r->family)
  92         {
  93                 warn_elem(e, "uses source ip with different family");
  94                 return false;
  95         }
  96
  97         if (r->ip_dest.family && r->ip_dest.family != r->family)
  98         {
  99                 warn_elem(e, "uses destination ip with different family");
 100                 return false;
 101         }
 102
 103         if (r->ip_redir.family && r->ip_redir.family != r->family)
 104         {
 105                 warn_elem(e, "uses redirect ip with different family");
 106                 return false;
 107         }
 108
 109         return true;
 110 }
 111
 112 void
 113 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 114 {
 115         struct uci_section *s;
 116         struct uci_element *e;
 117         struct fw3_redirect *redir;
 118
 119         bool valid;
 120
 121         INIT_LIST_HEAD(&state->redirects);
 122
 123         uci_foreach_element(&p->sections, e)
 124         {
 125                 s = uci_to_section(e);
 126
 127                 if (strcmp(s->type, "redirect"))
 128                         continue;
 129
 130                 redir = malloc(sizeof(*redir));
 131
 132                 if (!redir)
 133                         continue;
 134
 135                 memset(redir, 0, sizeof(*redir));
 136
 137                 INIT_LIST_HEAD(&redir->proto);
 138                 INIT_LIST_HEAD(&redir->mac_src);
 139
 140                 redir->enabled = true;
 141                 redir->reflection = true;
 142
 143                 valid = false;
 144
 145                 fw3_parse_options(redir, fw3_redirect_opts, s);
 146
 147                 if (!redir->enabled)
 148                 {
 149                         fw3_free_redirect(redir);
 150                         continue;
 151                 }
 152
 153                 if (redir->src.invert)
 154                 {
 155                         warn_elem(e, "must not have an inverted source");
 156                         fw3_free_redirect(redir);
 157                         continue;
 158                 }
 159                 else if (redir->src.set && !redir->src.any &&
 160                          !(redir->_src = fw3_lookup_zone(state, redir->src.name)))
 161                 {
 162                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 163                         fw3_free_redirect(redir);
 164                         continue;
 165                 }
 166                 else if (redir->dest.set && !redir->dest.any &&
 167                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name)))
 168                 {
 169                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 170                         fw3_free_redirect(redir);
 171                         continue;
 172                 }
 173                 else if (redir->ipset.set && state->disable_ipsets)
 174                 {
 175                         warn_elem(e, "skipped due to disabled ipset support");
 176                         fw3_free_redirect(redir);
 177                         continue;
 178                 }
 179                 else if (redir->ipset.set && !redir->ipset.any &&
 180                          !(redir->_ipset = fw3_lookup_ipset(state, redir->ipset.name)))
 181                 {
 182                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 183                         fw3_free_redirect(redir);
 184                         continue;
 185                 }
 186
 187                 if (!check_families(e, redir))
 188                 {
 189                         fw3_free_redirect(redir);
 190                         continue;
 191                 }
 192
 193                 if (redir->target == FW3_FLAG_UNSPEC)
 194                 {
 195                         warn_elem(e, "has no target specified, defaulting to DNAT");
 196                         redir->target = FW3_FLAG_DNAT;
 197                 }
 198                 else if (redir->target < FW3_FLAG_DNAT)
 199                 {
 200                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 201                         redir->target = FW3_FLAG_DNAT;
 202                 }
 203
 204                 if (redir->target == FW3_FLAG_DNAT)
 205                 {
 206                         if (redir->src.any)
 207                                 warn_elem(e, "must not have source '*' for DNAT target");
 208                         else if (!redir->_src)
 209                                 warn_elem(e, "has no source specified");
 210                         else
 211                         {
 212                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 213                                 redir->_src->conntrack = true;
 214                                 valid = true;
 215                         }
 216
 217                         if (redir->reflection && redir->_dest && redir->_src->masq)
 218                         {
 219                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 220                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 221                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 222                         }
 223                 }
 224                 else
 225                 {
 226                         if (redir->dest.any)
 227                                 warn_elem(e, "must not have destination '*' for SNAT target");
 228                         else if (!redir->_dest)
 229                                 warn_elem(e, "has no destination specified");
 230                         else if (!redir->ip_dest.set)
 231                                 warn_elem(e, "has no src_dip option specified");
 232                         else if (!list_empty(&redir->mac_src))
 233                                 warn_elem(e, "must not use 'src_mac' option for SNAT target");
 234                         else
 235                         {
 236                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 237                                 redir->_dest->conntrack = true;
 238                                 valid = true;
 239                         }
 240                 }
 241
 242                 if (list_empty(&redir->proto))
 243                 {
 244                         warn_elem(e, "does not specify a protocol, assuming TCP+UDP");
 245                         fw3_parse_protocol(&redir->proto, "tcpudp", true);
 246                 }
 247
 248                 if (!valid)
 249                 {
 250                         fw3_free_redirect(redir);
 251                         continue;
 252                 }
 253
 254                 if (!redir->port_redir.set)
 255                         redir->port_redir = redir->port_dest;
 256
 257                 list_add_tail(&redir->list, &state->redirects);
 258         }
 259 }
 260
 261 static void
 262 print_chain_nat(struct fw3_redirect *redir)
 263 {
 264         if (redir->target == FW3_FLAG_DNAT)
 265                 fw3_pr("-A zone_%s_prerouting", redir->src.name);
 266         else
 267                 fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 268 }
 269
 270 static void
 271 print_snat_dnat(enum fw3_flag target,
 272                 struct fw3_address *addr, struct fw3_port *port)
 273 {
 274         char s[sizeof("255.255.255.255 ")];
 275
 276         if (target == FW3_FLAG_DNAT)
 277                 fw3_pr(" -j DNAT --to-destination ");
 278         else
 279                 fw3_pr(" -j SNAT --to-source ");
 280
 281         if (addr && addr->set)
 282         {
 283                 inet_ntop(AF_INET, &addr->address.v4, s, sizeof(s));
 284                 fw3_pr(s);
 285         }
 286
 287         if (port && port->set)
 288         {
 289                 if (port->port_min == port->port_max)
 290                         fw3_pr(":%u", port->port_min);
 291                 else
 292                         fw3_pr(":%u-%u", port->port_min, port->port_max);
 293         }
 294
 295         fw3_pr("\n");
 296 }
 297
 298 static void
 299 print_target_nat(struct fw3_redirect *redir)
 300 {
 301         if (redir->target == FW3_FLAG_DNAT)
 302                 print_snat_dnat(redir->target, &redir->ip_redir, &redir->port_redir);
 303         else
 304                 print_snat_dnat(redir->target, &redir->ip_dest, &redir->port_dest);
 305 }
 306
 307 static void
 308 print_chain_filter(struct fw3_redirect *redir)
 309 {
 310         if (redir->target == FW3_FLAG_DNAT)
 311         {
 312                 /* XXX: check for local ip */
 313                 if (!redir->ip_redir.set)
 314                         fw3_pr("-A zone_%s_input", redir->src.name);
 315                 else
 316                         fw3_pr("-A zone_%s_forward", redir->src.name);
 317         }
 318         else
 319         {
 320                 if (redir->src.set && !redir->src.any)
 321                         fw3_pr("-A zone_%s_forward", redir->src.name);
 322                 else
 323                         fw3_pr("-A delegate_forward");
 324         }
 325 }
 326
 327 static void
 328 print_target_filter(struct fw3_redirect *redir)
 329 {
 330         /* XXX: check for local ip */
 331         if (redir->target == FW3_FLAG_DNAT && !redir->ip_redir.set)
 332                 fw3_pr(" -m conntrack --ctstate DNAT -j ACCEPT\n");
 333         else
 334                 fw3_pr(" -j ACCEPT\n");
 335 }
 336
 337 static void
 338 print_redirect(struct fw3_state *state, enum fw3_family family,
 339                enum fw3_table table, struct fw3_redirect *redir, int num)
 340 {
 341         struct list_head *ext_addrs, *int_addrs;
 342         struct fw3_address *ext_addr, *int_addr, ref_addr;
 343         struct fw3_device *ext_net, *int_net;
 344         struct fw3_protocol *proto;
 345         struct fw3_mac *mac;
 346
 347         if (redir->name)
 348                 info("   * Redirect '%s'", redir->name);
 349         else
 350                 info("   * Redirect #%u", num);
 351
 352         if (!fw3_is_family(redir->_src, family) ||
 353                 !fw3_is_family(redir->_dest, family))
 354         {
 355                 info("     ! Skipping due to different family of zone");
 356                 return;
 357         }
 358
 359         if (!fw3_is_family(&redir->ip_src, family) ||
 360             !fw3_is_family(&redir->ip_dest, family) ||
 361                 !fw3_is_family(&redir->ip_redir, family))
 362         {
 363                 info("     ! Skipping due to different family of ip address");
 364                 return;
 365         }
 366
 367         if (redir->_ipset)
 368         {
 369                 if (!fw3_is_family(redir->_ipset, family))
 370                 {
 371                         info("     ! Skipping due to different family in ipset");
 372                         return;
 373                 }
 374
 375                 if (!fw3_check_ipset(redir->_ipset))
 376                 {
 377                         info("     ! Skipping due to missing ipset '%s'",
 378                              (redir->_ipset->external && *redir->_ipset->external) ?
 379                                         redir->_ipset->external : redir->_ipset->name);
 380                         return;
 381                 }
 382
 383                 set(redir->_ipset->flags, family, family);
 384         }
 385
 386         fw3_foreach(proto, &redir->proto)
 387         fw3_foreach(mac, &redir->mac_src)
 388         {
 389                 if (table == FW3_TABLE_NAT)
 390                 {
 391                         print_chain_nat(redir);
 392                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 393                         fw3_format_protocol(proto, family);
 394
 395                         if (redir->target == FW3_FLAG_DNAT)
 396                         {
 397                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_dest);
 398                                 fw3_format_sport_dport(&redir->port_src, &redir->port_dest);
 399                         }
 400                         else
 401                         {
 402                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 403                                 fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 404                         }
 405
 406                         fw3_format_mac(mac);
 407                         fw3_format_time(&redir->time);
 408                         fw3_format_mark(&redir->mark);
 409                         fw3_format_extra(redir->extra);
 410                         fw3_format_comment(redir->name);
 411                         print_target_nat(redir);
 412                 }
 413                 else if (table == FW3_TABLE_FILTER)
 414                 {
 415                         print_chain_filter(redir);
 416                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 417                         fw3_format_protocol(proto, family);
 418                         fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 419                         fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 420                         fw3_format_mac(mac);
 421                         fw3_format_time(&redir->time);
 422                         fw3_format_mark(&redir->mark);
 423                         fw3_format_extra(redir->extra);
 424                         fw3_format_comment(redir->name);
 425                         print_target_filter(redir);
 426                 }
 427         }
 428
 429         /* reflection rules */
 430         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
 431                 return;
 432
 433         if (!redir->_dest || !redir->_src->masq)
 434                 return;
 435
 436         list_for_each_entry(ext_net, &redir->_src->networks, list)
 437         {
 438                 ext_addrs = fw3_ubus_address(ext_net->name);
 439
 440                 if (!ext_addrs || list_empty(ext_addrs))
 441                         continue;
 442
 443                 list_for_each_entry(int_net, &redir->_dest->networks, list)
 444                 {
 445                         int_addrs = fw3_ubus_address(int_net->name);
 446
 447                         if (!int_addrs || list_empty(int_addrs))
 448                                 continue;
 449
 450                         fw3_foreach(ext_addr, ext_addrs)
 451                         fw3_foreach(int_addr, int_addrs)
 452                         fw3_foreach(proto, &redir->proto)
 453                         {
 454                                 if (!fw3_is_family(int_addr, family) ||
 455                                     !fw3_is_family(ext_addr, family))
 456                                         continue;
 457
 458                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 459                                         continue;
 460
 461                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 462                                         ref_addr = *int_addr;
 463                                 else
 464                                         ref_addr = *ext_addr;
 465
 466                                 ref_addr.mask = 32;
 467                                 ext_addr->mask = 32;
 468
 469                                 if (table == FW3_TABLE_NAT)
 470                                 {
 471                                         fw3_pr("-A zone_%s_prerouting", redir->dest.name);
 472                                         fw3_format_protocol(proto, family);
 473                                         fw3_format_src_dest(int_addr, ext_addr);
 474                                         fw3_format_sport_dport(NULL, &redir->port_dest);
 475                                         fw3_format_time(&redir->time);
 476                                         fw3_format_comment(redir->name, " (reflection)");
 477                                         print_snat_dnat(FW3_FLAG_DNAT,
 478                                                         &redir->ip_redir, &redir->port_redir);
 479
 480                                         fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 481                                         fw3_format_protocol(proto, family);
 482                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 483                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 484                                         fw3_format_time(&redir->time);
 485                                         fw3_format_comment(redir->name, " (reflection)");
 486                                         print_snat_dnat(FW3_FLAG_SNAT, &ref_addr, NULL);
 487                                 }
 488                                 else if (table == FW3_TABLE_FILTER)
 489                                 {
 490                                         fw3_pr("-A zone_%s_forward", redir->dest.name);
 491                                         fw3_format_protocol(proto, family);
 492                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 493                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 494                                         fw3_format_time(&redir->time);
 495                                         fw3_format_comment(redir->name, " (reflection)");
 496                                         fw3_pr(" -j zone_%s_dest_ACCEPT\n", redir->dest.name);
 497                                 }
 498                         }
 499
 500                         fw3_ubus_address_free(int_addrs);
 501                 }
 502
 503                 fw3_ubus_address_free(ext_addrs);
 504         }
 505 }
 506
 507 void
 508 fw3_print_redirects(struct fw3_state *state, enum fw3_family family,
 509                     enum fw3_table table)
 510 {
 511         int num = 0;
 512         struct fw3_redirect *redir;
 513
 514         if (family == FW3_FAMILY_V6)
 515                 return;
 516
 517         if (table != FW3_TABLE_FILTER && table != FW3_TABLE_NAT)
 518                 return;
 519
 520         list_for_each_entry(redir, &state->redirects, list)
 521                 print_redirect(state, family, table, redir, num++);
 522 }