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