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
  57         FW3_OPT("target",              target,    redirect,     target),
  58
  59         { }
  60 };
  61
  62
  63 static bool
  64 check_families(struct uci_element *e, struct fw3_redirect *r)
  65 {
  66         if (r->family == FW3_FAMILY_ANY)
  67                 return true;
  68
  69         if (r->_src && r->_src->family && r->_src->family != r->family)
  70         {
  71                 warn_elem(e, "refers to source zone with different family");
  72                 return false;
  73         }
  74
  75         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  76         {
  77                 warn_elem(e, "refers to destination zone with different family");
  78                 return false;
  79         }
  80
  81         if (r->_ipset && r->_ipset->family && r->_ipset->family != r->family)
  82         {
  83                 warn_elem(e, "refers to ipset with different family");
  84                 return false;
  85         }
  86
  87         if (r->ip_src.family && r->ip_src.family != r->family)
  88         {
  89                 warn_elem(e, "uses source ip with different family");
  90                 return false;
  91         }
  92
  93         if (r->ip_dest.family && r->ip_dest.family != r->family)
  94         {
  95                 warn_elem(e, "uses destination ip with different family");
  96                 return false;
  97         }
  98
  99         if (r->ip_redir.family && r->ip_redir.family != r->family)
 100         {
 101                 warn_elem(e, "uses redirect ip with different family");
 102                 return false;
 103         }
 104
 105         return true;
 106 }
 107
 108 void
 109 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 110 {
 111         struct uci_section *s;
 112         struct uci_element *e;
 113         struct fw3_redirect *redir;
 114
 115         bool valid = false;
 116
 117         INIT_LIST_HEAD(&state->redirects);
 118
 119         uci_foreach_element(&p->sections, e)
 120         {
 121                 s = uci_to_section(e);
 122
 123                 if (strcmp(s->type, "redirect"))
 124                         continue;
 125
 126                 redir = malloc(sizeof(*redir));
 127
 128                 if (!redir)
 129                         continue;
 130
 131                 memset(redir, 0, sizeof(*redir));
 132
 133                 INIT_LIST_HEAD(&redir->proto);
 134                 INIT_LIST_HEAD(&redir->mac_src);
 135
 136                 redir->enabled = true;
 137                 redir->reflection = true;
 138
 139                 fw3_parse_options(redir, fw3_redirect_opts, s);
 140
 141                 if (!redir->enabled)
 142                 {
 143                         fw3_free_redirect(redir);
 144                         continue;
 145                 }
 146
 147                 if (redir->src.invert)
 148                 {
 149                         warn_elem(e, "must not have an inverted source");
 150                         fw3_free_redirect(redir);
 151                         continue;
 152                 }
 153                 else if (redir->src.set && !redir->src.any &&
 154                          !(redir->_src = fw3_lookup_zone(state, redir->src.name, false)))
 155                 {
 156                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 157                         fw3_free_redirect(redir);
 158                         continue;
 159                 }
 160                 else if (redir->dest.set && !redir->dest.any &&
 161                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name, false)))
 162                 {
 163                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 164                         fw3_free_redirect(redir);
 165                         continue;
 166                 }
 167                 else if (redir->ipset.set && state->disable_ipsets)
 168                 {
 169                         warn_elem(e, "skipped due to disabled ipset support");
 170                         fw3_free_redirect(redir);
 171                         continue;
 172                 }
 173                 else if (redir->ipset.set && !redir->ipset.any &&
 174                          !(redir->_ipset = fw3_lookup_ipset(state, redir->ipset.name, false)))
 175                 {
 176                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 177                         fw3_free_redirect(redir);
 178                         continue;
 179                 }
 180
 181                 if (!check_families(e, redir))
 182                 {
 183                         fw3_free_redirect(redir);
 184                         continue;
 185                 }
 186
 187                 if (redir->target == FW3_TARGET_UNSPEC)
 188                 {
 189                         warn_elem(e, "has no target specified, defaulting to DNAT");
 190                         redir->target = FW3_TARGET_DNAT;
 191                 }
 192                 else if (redir->target < FW3_TARGET_DNAT)
 193                 {
 194                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 195                         redir->target = FW3_TARGET_DNAT;
 196                 }
 197
 198                 if (redir->target == FW3_TARGET_DNAT)
 199                 {
 200                         if (redir->src.any)
 201                                 warn_elem(e, "must not have source '*' for DNAT target");
 202                         else if (!redir->_src)
 203                                 warn_elem(e, "has no source specified");
 204                         else
 205                         {
 206                                 setbit(redir->_src->dst_flags, redir->target);
 207                                 redir->_src->conntrack = true;
 208                                 valid = true;
 209                         }
 210
 211                         if (redir->reflection && redir->_dest && redir->_src->masq)
 212                         {
 213                                 setbit(redir->_dest->dst_flags, FW3_TARGET_ACCEPT);
 214                                 setbit(redir->_dest->dst_flags, FW3_TARGET_DNAT);
 215                                 setbit(redir->_dest->dst_flags, FW3_TARGET_SNAT);
 216                         }
 217                 }
 218                 else
 219                 {
 220                         if (redir->dest.any)
 221                                 warn_elem(e, "must not have destination '*' for SNAT target");
 222                         else if (!redir->_dest)
 223                                 warn_elem(e, "has no destination specified");
 224                         else if (!redir->ip_dest.set)
 225                                 warn_elem(e, "has no src_dip option specified");
 226                         else
 227                         {
 228                                 setbit(redir->_dest->dst_flags, redir->target);
 229                                 redir->_dest->conntrack = true;
 230                                 valid = true;
 231                         }
 232                 }
 233
 234                 if (!valid)
 235                 {
 236                         fw3_free_redirect(redir);
 237                         continue;
 238                 }
 239
 240                 if (!redir->port_redir.set)
 241                         redir->port_redir = redir->port_dest;
 242
 243                 list_add_tail(&redir->list, &state->redirects);
 244         }
 245 }
 246
 247 static void
 248 print_chain_nat(struct fw3_redirect *redir)
 249 {
 250         if (redir->target == FW3_TARGET_DNAT)
 251                 fw3_pr("-A zone_%s_prerouting", redir->src.name);
 252         else
 253                 fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 254 }
 255
 256 static void
 257 print_snat_dnat(enum fw3_target target,
 258                 struct fw3_address *addr, struct fw3_port *port)
 259 {
 260         const char *t;
 261         char s[sizeof("255.255.255.255 ")];
 262
 263         if (target == FW3_TARGET_DNAT)
 264                 t = "DNAT --to-destination";
 265         else
 266                 t = "SNAT --to-source";
 267
 268         inet_ntop(AF_INET, &addr->address.v4, s, sizeof(s));
 269
 270         fw3_pr(" -j %s %s", t, s);
 271
 272         if (port && port->set)
 273         {
 274                 if (port->port_min == port->port_max)
 275                         fw3_pr(":%u", port->port_min);
 276                 else
 277                         fw3_pr(":%u-%u", port->port_min, port->port_max);
 278         }
 279
 280         fw3_pr("\n");
 281 }
 282
 283 static void
 284 print_target_nat(struct fw3_redirect *redir)
 285 {
 286         if (redir->target == FW3_TARGET_DNAT)
 287                 print_snat_dnat(redir->target, &redir->ip_redir, &redir->port_redir);
 288         else
 289                 print_snat_dnat(redir->target, &redir->ip_dest, &redir->port_dest);
 290 }
 291
 292 static void
 293 print_chain_filter(struct fw3_redirect *redir)
 294 {
 295         if (redir->target == FW3_TARGET_DNAT)
 296         {
 297                 /* XXX: check for local ip */
 298                 if (!redir->ip_redir.set)
 299                         fw3_pr("-A zone_%s_input", redir->src.name);
 300                 else
 301                         fw3_pr("-A zone_%s_forward", redir->src.name);
 302         }
 303         else
 304         {
 305                 if (redir->src.set && !redir->src.any)
 306                         fw3_pr("-A zone_%s_forward", redir->src.name);
 307                 else
 308                         fw3_pr("-A delegate_forward");
 309         }
 310 }
 311
 312 static void
 313 print_target_filter(struct fw3_redirect *redir)
 314 {
 315         /* XXX: check for local ip */
 316         if (redir->target == FW3_TARGET_DNAT && !redir->ip_redir.set)
 317                 fw3_pr(" -m conntrack --ctstate DNAT -j ACCEPT\n");
 318         else
 319                 fw3_pr(" -j ACCEPT\n");
 320 }
 321
 322 static void
 323 print_redirect(enum fw3_table table, enum fw3_family family,
 324                struct fw3_redirect *redir, int num)
 325 {
 326         struct list_head *ext_addrs, *int_addrs;
 327         struct fw3_address *ext_addr, *int_addr;
 328         struct fw3_device *ext_net, *int_net;
 329         struct fw3_protocol *proto;
 330         struct fw3_mac *mac;
 331
 332         if (redir->name)
 333                 info("   * Redirect '%s'", redir->name);
 334         else
 335                 info("   * Redirect #%u", num);
 336
 337         if (!fw3_is_family(redir->_src, family) ||
 338                 !fw3_is_family(redir->_dest, family))
 339         {
 340                 info("     ! Skipping due to different family of zone");
 341                 return;
 342         }
 343
 344         if (!fw3_is_family(&redir->ip_src, family) ||
 345             !fw3_is_family(&redir->ip_dest, family) ||
 346                 !fw3_is_family(&redir->ip_redir, family))
 347         {
 348                 info("     ! Skipping due to different family of ip address");
 349                 return;
 350         }
 351
 352         if (redir->_ipset)
 353         {
 354                 if (!fw3_is_family(redir->_ipset, family))
 355                 {
 356                         info("     ! Skipping due to different family in ipset");
 357                         return;
 358                 }
 359
 360                 setbit(redir->_ipset->flags, family);
 361         }
 362
 363         fw3_foreach(proto, &redir->proto)
 364         fw3_foreach(mac, &redir->mac_src)
 365         {
 366                 if (table == FW3_TABLE_NAT)
 367                 {
 368                         print_chain_nat(redir);
 369                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 370                         fw3_format_protocol(proto, family);
 371
 372                         if (redir->target == FW3_TARGET_DNAT)
 373                         {
 374                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_dest);
 375                                 fw3_format_sport_dport(&redir->port_src, &redir->port_dest);
 376                         }
 377                         else
 378                         {
 379                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 380                                 fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 381                         }
 382
 383                         fw3_format_mac(mac);
 384                         fw3_format_time(&redir->time);
 385                         fw3_format_extra(redir->extra);
 386                         fw3_format_comment(redir->name);
 387                         print_target_nat(redir);
 388                 }
 389                 else if (table == FW3_TABLE_FILTER)
 390                 {
 391                         print_chain_filter(redir);
 392                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 393                         fw3_format_protocol(proto, family);
 394                         fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 395                         fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 396                         fw3_format_mac(mac);
 397                         fw3_format_time(&redir->time);
 398                         fw3_format_extra(redir->extra);
 399                         fw3_format_comment(redir->name);
 400                         print_target_filter(redir);
 401                 }
 402         }
 403
 404         /* reflection rules */
 405         if (redir->target != FW3_TARGET_DNAT || !redir->reflection)
 406                 return;
 407
 408         if (!redir->_dest || !redir->_src->masq)
 409                 return;
 410
 411         list_for_each_entry(ext_net, &redir->_src->networks, list)
 412         {
 413                 ext_addrs = fw3_ubus_address(ext_net->name);
 414
 415                 if (!ext_addrs || list_empty(ext_addrs))
 416                         continue;
 417
 418                 list_for_each_entry(int_net, &redir->_dest->networks, list)
 419                 {
 420                         int_addrs = fw3_ubus_address(int_net->name);
 421
 422                         if (!int_addrs || list_empty(int_addrs))
 423                                 continue;
 424
 425                         fw3_foreach(ext_addr, ext_addrs)
 426                         fw3_foreach(int_addr, int_addrs)
 427                         fw3_foreach(proto, &redir->proto)
 428                         {
 429                                 if (!fw3_is_family(int_addr, family) ||
 430                                     !fw3_is_family(ext_addr, family))
 431                                         continue;
 432
 433                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 434                                         continue;
 435
 436                                 ext_addr->mask = 32;
 437
 438                                 if (table == FW3_TABLE_NAT)
 439                                 {
 440                                         fw3_pr("-A zone_%s_prerouting", redir->dest.name);
 441                                         fw3_format_protocol(proto, family);
 442                                         fw3_format_src_dest(int_addr, ext_addr);
 443                                         fw3_format_sport_dport(NULL, &redir->port_dest);
 444                                         fw3_format_time(&redir->time);
 445                                         fw3_format_comment(redir->name, " (reflection)");
 446                                         print_snat_dnat(FW3_TARGET_DNAT,
 447                                                         &redir->ip_redir, &redir->port_redir);
 448
 449                                         fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 450                                         fw3_format_protocol(proto, family);
 451                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 452                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 453                                         fw3_format_time(&redir->time);
 454                                         fw3_format_comment(redir->name, " (reflection)");
 455                                         print_snat_dnat(FW3_TARGET_SNAT, ext_addr, NULL);
 456                                 }
 457                                 else if (table == FW3_TABLE_FILTER)
 458                                 {
 459                                         fw3_pr("-A zone_%s_forward", redir->dest.name);
 460                                         fw3_format_protocol(proto, family);
 461                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 462                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 463                                         fw3_format_time(&redir->time);
 464                                         fw3_format_comment(redir->name, " (reflection)");
 465                                         fw3_pr(" -j zone_%s_dest_ACCEPT\n", redir->dest.name);
 466                                 }
 467                         }
 468
 469                         fw3_ubus_address_free(int_addrs);
 470                 }
 471
 472                 fw3_ubus_address_free(ext_addrs);
 473         }
 474 }
 475
 476 void
 477 fw3_print_redirects(enum fw3_table table, enum fw3_family family,
 478                     struct fw3_state *state)
 479 {
 480         int num = 0;
 481         struct fw3_redirect *redir;
 482
 483         if (family == FW3_FAMILY_V6)
 484                 return;
 485
 486         if (table != FW3_TABLE_FILTER && table != FW3_TABLE_NAT)
 487                 return;
 488
 489         list_for_each_entry(redir, &state->redirects, list)
 490                 print_redirect(table, family, redir, num++);
 491 }