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("reflection",          bool,      redirect,     reflection),
  56         FW3_OPT("reflection_src",      reflection_source,
  57                                                   redirect,     reflection_src),
  58
  59         FW3_OPT("target",              target,    redirect,     target),
  60
  61         { }
  62 };
  63
  64
  65 static bool
  66 check_families(struct uci_element *e, struct fw3_redirect *r)
  67 {
  68         if (r->family == FW3_FAMILY_ANY)
  69                 return true;
  70
  71         if (r->_src && r->_src->family && r->_src->family != r->family)
  72         {
  73                 warn_elem(e, "refers to source zone with different family");
  74                 return false;
  75         }
  76
  77         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  78         {
  79                 warn_elem(e, "refers to destination zone with different family");
  80                 return false;
  81         }
  82
  83         if (r->_ipset && r->_ipset->family && r->_ipset->family != r->family)
  84         {
  85                 warn_elem(e, "refers to ipset with different family");
  86                 return false;
  87         }
  88
  89         if (r->ip_src.family && r->ip_src.family != r->family)
  90         {
  91                 warn_elem(e, "uses source ip with different family");
  92                 return false;
  93         }
  94
  95         if (r->ip_dest.family && r->ip_dest.family != r->family)
  96         {
  97                 warn_elem(e, "uses destination ip with different family");
  98                 return false;
  99         }
 100
 101         if (r->ip_redir.family && r->ip_redir.family != r->family)
 102         {
 103                 warn_elem(e, "uses redirect ip with different family");
 104                 return false;
 105         }
 106
 107         return true;
 108 }
 109
 110 void
 111 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 112 {
 113         struct uci_section *s;
 114         struct uci_element *e;
 115         struct fw3_redirect *redir;
 116
 117         bool valid = false;
 118
 119         INIT_LIST_HEAD(&state->redirects);
 120
 121         uci_foreach_element(&p->sections, e)
 122         {
 123                 s = uci_to_section(e);
 124
 125                 if (strcmp(s->type, "redirect"))
 126                         continue;
 127
 128                 redir = malloc(sizeof(*redir));
 129
 130                 if (!redir)
 131                         continue;
 132
 133                 memset(redir, 0, sizeof(*redir));
 134
 135                 INIT_LIST_HEAD(&redir->proto);
 136                 INIT_LIST_HEAD(&redir->mac_src);
 137
 138                 redir->enabled = true;
 139                 redir->reflection = true;
 140
 141                 fw3_parse_options(redir, fw3_redirect_opts, s);
 142
 143                 if (!redir->enabled)
 144                 {
 145                         fw3_free_redirect(redir);
 146                         continue;
 147                 }
 148
 149                 if (redir->src.invert)
 150                 {
 151                         warn_elem(e, "must not have an inverted source");
 152                         fw3_free_redirect(redir);
 153                         continue;
 154                 }
 155                 else if (redir->src.set && !redir->src.any &&
 156                          !(redir->_src = fw3_lookup_zone(state, redir->src.name, false)))
 157                 {
 158                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 159                         fw3_free_redirect(redir);
 160                         continue;
 161                 }
 162                 else if (redir->dest.set && !redir->dest.any &&
 163                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name, false)))
 164                 {
 165                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 166                         fw3_free_redirect(redir);
 167                         continue;
 168                 }
 169                 else if (redir->ipset.set && state->disable_ipsets)
 170                 {
 171                         warn_elem(e, "skipped due to disabled ipset support");
 172                         fw3_free_redirect(redir);
 173                         continue;
 174                 }
 175                 else if (redir->ipset.set && !redir->ipset.any &&
 176                          !(redir->_ipset = fw3_lookup_ipset(state, redir->ipset.name, false)))
 177                 {
 178                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 179                         fw3_free_redirect(redir);
 180                         continue;
 181                 }
 182
 183                 if (!check_families(e, redir))
 184                 {
 185                         fw3_free_redirect(redir);
 186                         continue;
 187                 }
 188
 189                 if (redir->target == FW3_FLAG_UNSPEC)
 190                 {
 191                         warn_elem(e, "has no target specified, defaulting to DNAT");
 192                         redir->target = FW3_FLAG_DNAT;
 193                 }
 194                 else if (redir->target < FW3_FLAG_DNAT)
 195                 {
 196                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 197                         redir->target = FW3_FLAG_DNAT;
 198                 }
 199
 200                 if (redir->target == FW3_FLAG_DNAT)
 201                 {
 202                         if (redir->src.any)
 203                                 warn_elem(e, "must not have source '*' for DNAT target");
 204                         else if (!redir->_src)
 205                                 warn_elem(e, "has no source specified");
 206                         else
 207                         {
 208                                 set(redir->_src->flags, FW3_FAMILY_V4, redir->target);
 209                                 redir->_src->conntrack = true;
 210                                 valid = true;
 211                         }
 212
 213                         if (redir->reflection && redir->_dest && redir->_src->masq)
 214                         {
 215                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT);
 216                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT);
 217                                 set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT);
 218                         }
 219                 }
 220                 else
 221                 {
 222                         if (redir->dest.any)
 223                                 warn_elem(e, "must not have destination '*' for SNAT target");
 224                         else if (!redir->_dest)
 225                                 warn_elem(e, "has no destination specified");
 226                         else if (!redir->ip_dest.set)
 227                                 warn_elem(e, "has no src_dip option specified");
 228                         else
 229                         {
 230                                 set(redir->_dest->flags, FW3_FAMILY_V4, redir->target);
 231                                 redir->_dest->conntrack = true;
 232                                 valid = true;
 233                         }
 234                 }
 235
 236                 if (!valid)
 237                 {
 238                         fw3_free_redirect(redir);
 239                         continue;
 240                 }
 241
 242                 if (!redir->port_redir.set)
 243                         redir->port_redir = redir->port_dest;
 244
 245                 list_add_tail(&redir->list, &state->redirects);
 246         }
 247 }
 248
 249 static void
 250 print_chain_nat(struct fw3_redirect *redir)
 251 {
 252         if (redir->target == FW3_FLAG_DNAT)
 253                 fw3_pr("-A zone_%s_prerouting", redir->src.name);
 254         else
 255                 fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 256 }
 257
 258 static void
 259 print_snat_dnat(enum fw3_flag target,
 260                 struct fw3_address *addr, struct fw3_port *port)
 261 {
 262         const char *t;
 263         char s[sizeof("255.255.255.255 ")];
 264
 265         if (target == FW3_FLAG_DNAT)
 266                 t = "DNAT --to-destination";
 267         else
 268                 t = "SNAT --to-source";
 269
 270         inet_ntop(AF_INET, &addr->address.v4, s, sizeof(s));
 271
 272         fw3_pr(" -j %s %s", t, s);
 273
 274         if (port && port->set)
 275         {
 276                 if (port->port_min == port->port_max)
 277                         fw3_pr(":%u", port->port_min);
 278                 else
 279                         fw3_pr(":%u-%u", port->port_min, port->port_max);
 280         }
 281
 282         fw3_pr("\n");
 283 }
 284
 285 static void
 286 print_target_nat(struct fw3_redirect *redir)
 287 {
 288         if (redir->target == FW3_FLAG_DNAT)
 289                 print_snat_dnat(redir->target, &redir->ip_redir, &redir->port_redir);
 290         else
 291                 print_snat_dnat(redir->target, &redir->ip_dest, &redir->port_dest);
 292 }
 293
 294 static void
 295 print_chain_filter(struct fw3_redirect *redir)
 296 {
 297         if (redir->target == FW3_FLAG_DNAT)
 298         {
 299                 /* XXX: check for local ip */
 300                 if (!redir->ip_redir.set)
 301                         fw3_pr("-A zone_%s_input", redir->src.name);
 302                 else
 303                         fw3_pr("-A zone_%s_forward", redir->src.name);
 304         }
 305         else
 306         {
 307                 if (redir->src.set && !redir->src.any)
 308                         fw3_pr("-A zone_%s_forward", redir->src.name);
 309                 else
 310                         fw3_pr("-A delegate_forward");
 311         }
 312 }
 313
 314 static void
 315 print_target_filter(struct fw3_redirect *redir)
 316 {
 317         /* XXX: check for local ip */
 318         if (redir->target == FW3_FLAG_DNAT && !redir->ip_redir.set)
 319                 fw3_pr(" -m conntrack --ctstate DNAT -j ACCEPT\n");
 320         else
 321                 fw3_pr(" -j ACCEPT\n");
 322 }
 323
 324 static void
 325 print_redirect(enum fw3_table table, enum fw3_family family,
 326                struct fw3_redirect *redir, int num)
 327 {
 328         struct list_head *ext_addrs, *int_addrs;
 329         struct fw3_address *ext_addr, *int_addr, ref_addr;
 330         struct fw3_device *ext_net, *int_net;
 331         struct fw3_protocol *proto;
 332         struct fw3_mac *mac;
 333
 334         if (redir->name)
 335                 info("   * Redirect '%s'", redir->name);
 336         else
 337                 info("   * Redirect #%u", num);
 338
 339         if (!fw3_is_family(redir->_src, family) ||
 340                 !fw3_is_family(redir->_dest, family))
 341         {
 342                 info("     ! Skipping due to different family of zone");
 343                 return;
 344         }
 345
 346         if (!fw3_is_family(&redir->ip_src, family) ||
 347             !fw3_is_family(&redir->ip_dest, family) ||
 348                 !fw3_is_family(&redir->ip_redir, family))
 349         {
 350                 info("     ! Skipping due to different family of ip address");
 351                 return;
 352         }
 353
 354         if (redir->_ipset)
 355         {
 356                 if (!fw3_is_family(redir->_ipset, family))
 357                 {
 358                         info("     ! Skipping due to different family in ipset");
 359                         return;
 360                 }
 361
 362                 set(redir->_ipset->flags, family, family);
 363         }
 364
 365         fw3_foreach(proto, &redir->proto)
 366         fw3_foreach(mac, &redir->mac_src)
 367         {
 368                 if (table == FW3_TABLE_NAT)
 369                 {
 370                         print_chain_nat(redir);
 371                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 372                         fw3_format_protocol(proto, family);
 373
 374                         if (redir->target == FW3_FLAG_DNAT)
 375                         {
 376                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_dest);
 377                                 fw3_format_sport_dport(&redir->port_src, &redir->port_dest);
 378                         }
 379                         else
 380                         {
 381                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 382                                 fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 383                         }
 384
 385                         fw3_format_mac(mac);
 386                         fw3_format_time(&redir->time);
 387                         fw3_format_extra(redir->extra);
 388                         fw3_format_comment(redir->name);
 389                         print_target_nat(redir);
 390                 }
 391                 else if (table == FW3_TABLE_FILTER)
 392                 {
 393                         print_chain_filter(redir);
 394                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 395                         fw3_format_protocol(proto, family);
 396                         fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 397                         fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 398                         fw3_format_mac(mac);
 399                         fw3_format_time(&redir->time);
 400                         fw3_format_extra(redir->extra);
 401                         fw3_format_comment(redir->name);
 402                         print_target_filter(redir);
 403                 }
 404         }
 405
 406         /* reflection rules */
 407         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
 408                 return;
 409
 410         if (!redir->_dest || !redir->_src->masq)
 411                 return;
 412
 413         list_for_each_entry(ext_net, &redir->_src->networks, list)
 414         {
 415                 ext_addrs = fw3_ubus_address(ext_net->name);
 416
 417                 if (!ext_addrs || list_empty(ext_addrs))
 418                         continue;
 419
 420                 list_for_each_entry(int_net, &redir->_dest->networks, list)
 421                 {
 422                         int_addrs = fw3_ubus_address(int_net->name);
 423
 424                         if (!int_addrs || list_empty(int_addrs))
 425                                 continue;
 426
 427                         fw3_foreach(ext_addr, ext_addrs)
 428                         fw3_foreach(int_addr, int_addrs)
 429                         fw3_foreach(proto, &redir->proto)
 430                         {
 431                                 if (!fw3_is_family(int_addr, family) ||
 432                                     !fw3_is_family(ext_addr, family))
 433                                         continue;
 434
 435                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 436                                         continue;
 437
 438                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 439                                         ref_addr = *int_addr;
 440                                 else
 441                                         ref_addr = *ext_addr;
 442
 443                                 ref_addr.mask = 32;
 444                                 ext_addr->mask = 32;
 445
 446                                 if (table == FW3_TABLE_NAT)
 447                                 {
 448                                         fw3_pr("-A zone_%s_prerouting", redir->dest.name);
 449                                         fw3_format_protocol(proto, family);
 450                                         fw3_format_src_dest(int_addr, ext_addr);
 451                                         fw3_format_sport_dport(NULL, &redir->port_dest);
 452                                         fw3_format_time(&redir->time);
 453                                         fw3_format_comment(redir->name, " (reflection)");
 454                                         print_snat_dnat(FW3_FLAG_DNAT,
 455                                                         &redir->ip_redir, &redir->port_redir);
 456
 457                                         fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 458                                         fw3_format_protocol(proto, family);
 459                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 460                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 461                                         fw3_format_time(&redir->time);
 462                                         fw3_format_comment(redir->name, " (reflection)");
 463                                         print_snat_dnat(FW3_FLAG_SNAT, &ref_addr, NULL);
 464                                 }
 465                                 else if (table == FW3_TABLE_FILTER)
 466                                 {
 467                                         fw3_pr("-A zone_%s_forward", redir->dest.name);
 468                                         fw3_format_protocol(proto, family);
 469                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 470                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 471                                         fw3_format_time(&redir->time);
 472                                         fw3_format_comment(redir->name, " (reflection)");
 473                                         fw3_pr(" -j zone_%s_dest_ACCEPT\n", redir->dest.name);
 474                                 }
 475                         }
 476
 477                         fw3_ubus_address_free(int_addrs);
 478                 }
 479
 480                 fw3_ubus_address_free(ext_addrs);
 481         }
 482 }
 483
 484 void
 485 fw3_print_redirects(enum fw3_table table, enum fw3_family family,
 486                     struct fw3_state *state)
 487 {
 488         int num = 0;
 489         struct fw3_redirect *redir;
 490
 491         if (family == FW3_FAMILY_V6)
 492                 return;
 493
 494         if (table != FW3_TABLE_FILTER && table != FW3_TABLE_NAT)
 495                 return;
 496
 497         list_for_each_entry(redir, &state->redirects, list)
 498                 print_redirect(table, family, redir, num++);
 499 }