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 append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 263 {
 264         if (redir->target == FW3_FLAG_DNAT)
 265                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name);
 266         else
 267                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 268 }
 269
 270 static void
 271 set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target,
 272               struct fw3_address *addr, struct fw3_port *port)
 273 {
 274         char buf[sizeof("255.255.255.255:65535-65535\0")];
 275
 276         buf[0] = '\0';
 277
 278         if (addr && addr->set)
 279         {
 280                 inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf));
 281         }
 282
 283         if (port && port->set)
 284         {
 285                 if (port->port_min == port->port_max)
 286                         sprintf(buf + strlen(buf), ":%u", port->port_min);
 287                 else
 288                         sprintf(buf + strlen(buf), ":%u-%u",
 289                                 port->port_min, port->port_max);
 290         }
 291
 292         if (target == FW3_FLAG_DNAT)
 293         {
 294                 fw3_ipt_rule_target(r, "DNAT");
 295                 fw3_ipt_rule_addarg(r, false, "--to-destination", buf);
 296         }
 297         else
 298         {
 299                 fw3_ipt_rule_target(r, "SNAT");
 300                 fw3_ipt_rule_addarg(r, false, "--to-source", buf);
 301         }
 302 }
 303
 304 static void
 305 set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 306 {
 307         if (redir->target == FW3_FLAG_DNAT)
 308                 set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir);
 309         else
 310                 set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest);
 311 }
 312
 313 static void
 314 append_chain_filter(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 315 {
 316         if (redir->target == FW3_FLAG_DNAT)
 317         {
 318                 /* XXX: check for local ip */
 319                 if (!redir->ip_redir.set)
 320                         fw3_ipt_rule_append(r, "zone_%s_input", redir->src.name);
 321                 else
 322                         fw3_ipt_rule_append(r, "zone_%s_forward", redir->src.name);
 323         }
 324         else
 325         {
 326                 if (redir->src.set && !redir->src.any)
 327                         fw3_ipt_rule_append(r, "zone_%s_forward", redir->src.name);
 328                 else
 329                         fw3_ipt_rule_append(r, "delegate_forward");
 330         }
 331 }
 332
 333 static void
 334 set_target_filter(struct fw3_ipt_rule *r, struct fw3_redirect *redir)
 335 {
 336         /* XXX: check for local ip */
 337         if (redir->target == FW3_FLAG_DNAT && !redir->ip_redir.set)
 338                 fw3_ipt_rule_extra(r, "-m conntrack --ctstate DNAT");
 339
 340         fw3_ipt_rule_target(r, "ACCEPT");
 341 }
 342
 343 static void
 344 set_comment(struct fw3_ipt_rule *r, const char *name, int num, bool ref)
 345 {
 346         if (name)
 347         {
 348                 if (ref)
 349                         fw3_ipt_rule_comment(r, "%s (reflection)", name);
 350                 else
 351                         fw3_ipt_rule_comment(r, name);
 352         }
 353         else
 354         {
 355                 if (ref)
 356                         fw3_ipt_rule_comment(r, "@redirect[%u] (reflection)", num);
 357                 else
 358                         fw3_ipt_rule_comment(r, "@redirect[%u]", num);
 359         }
 360 }
 361
 362 static void
 363 print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state,
 364                struct fw3_redirect *redir, int num,
 365                struct fw3_protocol *proto, struct fw3_mac *mac)
 366 {
 367         struct fw3_ipt_rule *r;
 368         struct fw3_address *src, *dst;
 369         struct fw3_port *spt, *dpt;
 370
 371         switch (h->table)
 372         {
 373         case FW3_TABLE_NAT:
 374                 src = &redir->ip_src;
 375                 dst = &redir->ip_dest;
 376                 spt = &redir->port_src;
 377                 dpt = &redir->port_dest;
 378
 379                 if (redir->target == FW3_FLAG_SNAT)
 380                 {
 381                         dst = &redir->ip_redir;
 382                         dpt = &redir->port_redir;
 383                 }
 384
 385                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 386                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 387                 fw3_ipt_rule_mac(r, mac);
 388                 fw3_ipt_rule_ipset(r, redir->_ipset, redir->ipset.invert);
 389                 fw3_ipt_rule_time(r, &redir->time);
 390                 fw3_ipt_rule_mark(r, &redir->mark);
 391                 set_target_nat(r, redir);
 392                 fw3_ipt_rule_extra(r, redir->extra);
 393                 set_comment(r, redir->name, num, false);
 394                 append_chain_nat(r, redir);
 395                 break;
 396
 397         case FW3_TABLE_FILTER:
 398                 src = &redir->ip_src;
 399                 dst = &redir->ip_redir;
 400                 spt = &redir->port_src;
 401                 dpt = &redir->port_redir;
 402
 403                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst);
 404                 fw3_ipt_rule_sport_dport(r, spt, dpt);
 405                 fw3_ipt_rule_mac(r, mac);
 406                 fw3_ipt_rule_ipset(r, redir->_ipset, redir->ipset.invert);
 407                 fw3_ipt_rule_time(r, &redir->time);
 408                 fw3_ipt_rule_mark(r, &redir->mark);
 409                 set_target_filter(r, redir);
 410                 fw3_ipt_rule_extra(r, redir->extra);
 411                 set_comment(r, redir->name, num, false);
 412                 append_chain_filter(r, redir);
 413                 break;
 414
 415         default:
 416                 break;
 417         }
 418 }
 419
 420 static void
 421 print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state,
 422                  struct fw3_redirect *redir, int num,
 423                  struct fw3_protocol *proto, struct fw3_address *ra,
 424                  struct fw3_address *ia, struct fw3_address *ea)
 425 {
 426         struct fw3_ipt_rule *r;
 427
 428         switch (h->table)
 429         {
 430         case FW3_TABLE_NAT:
 431                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea);
 432                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest);
 433                 fw3_ipt_rule_time(r, &redir->time);
 434                 set_comment(r, redir->name, num, true);
 435                 set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir);
 436                 fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->dest.name);
 437
 438                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 439                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 440                 fw3_ipt_rule_time(r, &redir->time);
 441                 set_comment(r, redir->name, num, true);
 442                 set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL);
 443                 fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name);
 444                 break;
 445
 446         case FW3_TABLE_FILTER:
 447                 r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir);
 448                 fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir);
 449                 fw3_ipt_rule_time(r, &redir->time);
 450                 set_comment(r, redir->name, num, true);
 451                 fw3_ipt_rule_target(r, "zone_%s_dest_ACCEPT", redir->dest.name);
 452                 fw3_ipt_rule_append(r, "zone_%s_forward", redir->dest.name);
 453                 break;
 454
 455         default:
 456                 break;
 457         }
 458 }
 459
 460 static void
 461 expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state,
 462                 struct fw3_redirect *redir, int num)
 463 {
 464         struct list_head *ext_addrs, *int_addrs;
 465         struct fw3_address *ext_addr, *int_addr, ref_addr;
 466         struct fw3_device *ext_net, *int_net;
 467         struct fw3_protocol *proto;
 468         struct fw3_mac *mac;
 469
 470         if (redir->name)
 471                 info("   * Redirect '%s'", redir->name);
 472         else
 473                 info("   * Redirect #%u", num);
 474
 475         if (!fw3_is_family(redir->_src, handle->family) ||
 476                 !fw3_is_family(redir->_dest, handle->family))
 477         {
 478                 info("     ! Skipping due to different family of zone");
 479                 return;
 480         }
 481
 482         if (!fw3_is_family(&redir->ip_src, handle->family) ||
 483             !fw3_is_family(&redir->ip_dest, handle->family) ||
 484                 !fw3_is_family(&redir->ip_redir, handle->family))
 485         {
 486                 info("     ! Skipping due to different family of ip address");
 487                 return;
 488         }
 489
 490         if (redir->_ipset)
 491         {
 492                 if (!fw3_is_family(redir->_ipset, handle->family))
 493                 {
 494                         info("     ! Skipping due to different family in ipset");
 495                         return;
 496                 }
 497
 498                 if (!fw3_check_ipset(redir->_ipset))
 499                 {
 500                         info("     ! Skipping due to missing ipset '%s'",
 501                              redir->_ipset->external ?
 502                                         redir->_ipset->external : redir->_ipset->name);
 503                         return;
 504                 }
 505
 506                 set(redir->_ipset->flags, handle->family, handle->family);
 507         }
 508
 509         fw3_foreach(proto, &redir->proto)
 510         fw3_foreach(mac, &redir->mac_src)
 511                 print_redirect(handle, state, redir, num, proto, mac);
 512
 513         /* reflection rules */
 514         if (redir->target != FW3_FLAG_DNAT || !redir->reflection)
 515                 return;
 516
 517         if (!redir->_dest || !redir->_src->masq)
 518                 return;
 519
 520         list_for_each_entry(ext_net, &redir->_src->networks, list)
 521         {
 522                 ext_addrs = fw3_ubus_address(ext_net->name);
 523
 524                 if (!ext_addrs || list_empty(ext_addrs))
 525                         continue;
 526
 527                 list_for_each_entry(int_net, &redir->_dest->networks, list)
 528                 {
 529                         int_addrs = fw3_ubus_address(int_net->name);
 530
 531                         if (!int_addrs || list_empty(int_addrs))
 532                                 continue;
 533
 534                         fw3_foreach(ext_addr, ext_addrs)
 535                         fw3_foreach(int_addr, int_addrs)
 536                         fw3_foreach(proto, &redir->proto)
 537                         {
 538                                 if (!fw3_is_family(int_addr, handle->family) ||
 539                                     !fw3_is_family(ext_addr, handle->family))
 540                                         continue;
 541
 542                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 543                                         continue;
 544
 545                                 if (redir->reflection_src == FW3_REFLECTION_INTERNAL)
 546                                         ref_addr = *int_addr;
 547                                 else
 548                                         ref_addr = *ext_addr;
 549
 550                                 ref_addr.mask = 32;
 551                                 ext_addr->mask = 32;
 552
 553                                 print_reflection(handle, state, redir, num, proto,
 554                                                                  &ref_addr, int_addr, ext_addr);
 555                         }
 556
 557                         fw3_ubus_address_free(int_addrs);
 558                 }
 559
 560                 fw3_ubus_address_free(ext_addrs);
 561         }
 562 }
 563
 564 void
 565 fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state)
 566 {
 567         int num = 0;
 568         struct fw3_redirect *redir;
 569
 570         if (handle->family == FW3_FAMILY_V6)
 571                 return;
 572
 573         if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT)
 574                 return;
 575
 576         list_for_each_entry(redir, &state->redirects, list)
 577                 expand_redirect(handle, state, redir, num++);
 578 }