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("name",                string,   redirect,     name),
  24         FW3_OPT("family",              family,   redirect,     family),
  25
  26         FW3_OPT("src",                 device,   redirect,     src),
  27         FW3_OPT("dest",                device,   redirect,     dest),
  28
  29         FW3_OPT("ipset",               device,   redirect,     ipset),
  30
  31         FW3_LIST("proto",              protocol, redirect,     proto),
  32
  33         FW3_OPT("src_ip",              address,  redirect,     ip_src),
  34         FW3_LIST("src_mac",            mac,      redirect,     mac_src),
  35         FW3_OPT("src_port",            port,     redirect,     port_src),
  36
  37         FW3_OPT("src_dip",             address,  redirect,     ip_dest),
  38         FW3_OPT("src_dport",           port,     redirect,     port_dest),
  39
  40         FW3_OPT("dest_ip",             address,  redirect,     ip_redir),
  41         FW3_OPT("dest_port",           port,     redirect,     port_redir),
  42
  43         FW3_OPT("extra",               string,   redirect,     extra),
  44
  45         FW3_OPT("reflection",          bool,     redirect,     reflection),
  46
  47         FW3_OPT("target",              target,   redirect,     target),
  48
  49         { }
  50 };
  51
  52
  53 static bool
  54 check_families(struct uci_element *e, struct fw3_redirect *r)
  55 {
  56         if (r->family == FW3_FAMILY_ANY)
  57                 return true;
  58
  59         if (r->_src && r->_src->family && r->_src->family != r->family)
  60         {
  61                 warn_elem(e, "refers to source zone with different family");
  62                 return false;
  63         }
  64
  65         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  66         {
  67                 warn_elem(e, "refers to destination zone with different family");
  68                 return false;
  69         }
  70
  71         if (r->_ipset && r->_ipset->family && r->_ipset->family != r->family)
  72         {
  73                 warn_elem(e, "refers to ipset with different family");
  74                 return false;
  75         }
  76
  77         if (r->ip_src.family && r->ip_src.family != r->family)
  78         {
  79                 warn_elem(e, "uses source ip with different family");
  80                 return false;
  81         }
  82
  83         if (r->ip_dest.family && r->ip_dest.family != r->family)
  84         {
  85                 warn_elem(e, "uses destination ip with different family");
  86                 return false;
  87         }
  88
  89         if (r->ip_redir.family && r->ip_redir.family != r->family)
  90         {
  91                 warn_elem(e, "uses redirect ip with different family");
  92                 return false;
  93         }
  94
  95         return true;
  96 }
  97
  98 void
  99 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 100 {
 101         struct uci_section *s;
 102         struct uci_element *e;
 103         struct fw3_redirect *redir;
 104
 105         bool valid = false;
 106
 107         INIT_LIST_HEAD(&state->redirects);
 108
 109         uci_foreach_element(&p->sections, e)
 110         {
 111                 s = uci_to_section(e);
 112
 113                 if (strcmp(s->type, "redirect"))
 114                         continue;
 115
 116                 redir = malloc(sizeof(*redir));
 117
 118                 if (!redir)
 119                         continue;
 120
 121                 memset(redir, 0, sizeof(*redir));
 122
 123                 INIT_LIST_HEAD(&redir->proto);
 124                 INIT_LIST_HEAD(&redir->mac_src);
 125
 126                 redir->reflection = true;
 127
 128                 fw3_parse_options(redir, fw3_redirect_opts, s);
 129
 130                 if (redir->src.invert)
 131                 {
 132                         warn_elem(e, "must not have an inverted source");
 133                         fw3_free_redirect(redir);
 134                         continue;
 135                 }
 136                 else if (redir->src.set && !redir->src.any &&
 137                          !(redir->_src = fw3_lookup_zone(state, redir->src.name, false)))
 138                 {
 139                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 140                         fw3_free_redirect(redir);
 141                         continue;
 142                 }
 143                 else if (redir->dest.set && !redir->dest.any &&
 144                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name, false)))
 145                 {
 146                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 147                         fw3_free_redirect(redir);
 148                         continue;
 149                 }
 150                 else if (redir->ipset.set && state->disable_ipsets)
 151                 {
 152                         warn_elem(e, "skipped due to disabled ipset support");
 153                         fw3_free_redirect(redir);
 154                         continue;
 155                 }
 156                 else if (redir->ipset.set && !redir->ipset.any &&
 157                          !(redir->_ipset = fw3_lookup_ipset(state, redir->ipset.name, false)))
 158                 {
 159                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 160                         fw3_free_redirect(redir);
 161                         continue;
 162                 }
 163
 164                 if (!check_families(e, redir))
 165                 {
 166                         fw3_free_redirect(redir);
 167                         continue;
 168                 }
 169
 170                 if (redir->target == FW3_TARGET_UNSPEC)
 171                 {
 172                         warn_elem(e, "has no target specified, defaulting to DNAT");
 173                         redir->target = FW3_TARGET_DNAT;
 174                 }
 175                 else if (redir->target < FW3_TARGET_DNAT)
 176                 {
 177                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 178                         redir->target = FW3_TARGET_DNAT;
 179                 }
 180
 181                 if (redir->target == FW3_TARGET_DNAT)
 182                 {
 183                         if (redir->src.any)
 184                                 warn_elem(e, "must not have source '*' for DNAT target");
 185                         else if (!redir->_src)
 186                                 warn_elem(e, "has no source specified");
 187                         else
 188                         {
 189                                 setbit(redir->_src->dst_flags, redir->target);
 190                                 redir->_src->conntrack = true;
 191                                 valid = true;
 192                         }
 193
 194                         if (redir->reflection && redir->_dest && redir->_src->masq)
 195                         {
 196                                 setbit(redir->_dest->dst_flags, FW3_TARGET_ACCEPT);
 197                                 setbit(redir->_dest->dst_flags, FW3_TARGET_DNAT);
 198                                 setbit(redir->_dest->dst_flags, FW3_TARGET_SNAT);
 199                         }
 200                 }
 201                 else
 202                 {
 203                         if (redir->dest.any)
 204                                 warn_elem(e, "must not have destination '*' for SNAT target");
 205                         else if (!redir->_dest)
 206                                 warn_elem(e, "has no destination specified");
 207                         else if (!redir->ip_dest.set)
 208                                 warn_elem(e, "has no src_dip option specified");
 209                         else
 210                         {
 211                                 setbit(redir->_dest->dst_flags, redir->target);
 212                                 redir->_dest->conntrack = true;
 213                                 valid = true;
 214                         }
 215                 }
 216
 217                 if (!valid)
 218                 {
 219                         fw3_free_redirect(redir);
 220                         continue;
 221                 }
 222
 223                 if (!redir->port_redir.set)
 224                         redir->port_redir = redir->port_dest;
 225
 226                 list_add_tail(&redir->list, &state->redirects);
 227         }
 228 }
 229
 230 static void
 231 print_chain_nat(struct fw3_redirect *redir)
 232 {
 233         if (redir->target == FW3_TARGET_DNAT)
 234                 fw3_pr("-A zone_%s_prerouting", redir->src.name);
 235         else
 236                 fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 237 }
 238
 239 static void
 240 print_snat_dnat(enum fw3_target target,
 241                 struct fw3_address *addr, struct fw3_port *port)
 242 {
 243         const char *t;
 244         char s[sizeof("255.255.255.255 ")];
 245
 246         if (target == FW3_TARGET_DNAT)
 247                 t = "DNAT --to-destination";
 248         else
 249                 t = "SNAT --to-source";
 250
 251         inet_ntop(AF_INET, &addr->address.v4, s, sizeof(s));
 252
 253         fw3_pr(" -j %s %s", t, s);
 254
 255         if (port && port->set)
 256         {
 257                 if (port->port_min == port->port_max)
 258                         fw3_pr(":%u", port->port_min);
 259                 else
 260                         fw3_pr(":%u-%u", port->port_min, port->port_max);
 261         }
 262
 263         fw3_pr("\n");
 264 }
 265
 266 static void
 267 print_target_nat(struct fw3_redirect *redir)
 268 {
 269         if (redir->target == FW3_TARGET_DNAT)
 270                 print_snat_dnat(redir->target, &redir->ip_redir, &redir->port_redir);
 271         else
 272                 print_snat_dnat(redir->target, &redir->ip_dest, &redir->port_dest);
 273 }
 274
 275 static void
 276 print_chain_filter(struct fw3_redirect *redir)
 277 {
 278         if (redir->target == FW3_TARGET_DNAT)
 279         {
 280                 /* XXX: check for local ip */
 281                 if (!redir->ip_redir.set)
 282                         fw3_pr("-A zone_%s_input", redir->src.name);
 283                 else
 284                         fw3_pr("-A zone_%s_forward", redir->src.name);
 285         }
 286         else
 287         {
 288                 if (redir->src.set && !redir->src.any)
 289                         fw3_pr("-A zone_%s_forward", redir->src.name);
 290                 else
 291                         fw3_pr("-A delegate_forward");
 292         }
 293 }
 294
 295 static void
 296 print_target_filter(struct fw3_redirect *redir)
 297 {
 298         /* XXX: check for local ip */
 299         if (redir->target == FW3_TARGET_DNAT && !redir->ip_redir.set)
 300                 fw3_pr(" -m conntrack --ctstate DNAT -j ACCEPT\n");
 301         else
 302                 fw3_pr(" -j ACCEPT\n");
 303 }
 304
 305 static void
 306 print_redirect(enum fw3_table table, enum fw3_family family,
 307                struct fw3_redirect *redir, int num)
 308 {
 309         struct list_head *ext_addrs, *int_addrs;
 310         struct fw3_address *ext_addr, *int_addr;
 311         struct fw3_device *ext_net, *int_net;
 312         struct fw3_protocol *proto;
 313         struct fw3_mac *mac;
 314
 315         if (redir->name)
 316                 info("   * Redirect '%s'", redir->name);
 317         else
 318                 info("   * Redirect #%u", num);
 319
 320         if (!fw3_is_family(redir->_src, family) ||
 321                 !fw3_is_family(redir->_dest, family))
 322         {
 323                 info("     ! Skipping due to different family of zone");
 324                 return;
 325         }
 326
 327         if (!fw3_is_family(&redir->ip_src, family) ||
 328             !fw3_is_family(&redir->ip_dest, family) ||
 329                 !fw3_is_family(&redir->ip_redir, family))
 330         {
 331                 info("     ! Skipping due to different family of ip address");
 332                 return;
 333         }
 334
 335         if (redir->_ipset)
 336         {
 337                 if (!fw3_is_family(redir->_ipset, family))
 338                 {
 339                         info("     ! Skipping due to different family in ipset");
 340                         return;
 341                 }
 342
 343                 setbit(redir->_ipset->flags, family);
 344         }
 345
 346         fw3_foreach(proto, &redir->proto)
 347         fw3_foreach(mac, &redir->mac_src)
 348         {
 349                 if (table == FW3_TABLE_NAT)
 350                 {
 351                         print_chain_nat(redir);
 352                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 353                         fw3_format_protocol(proto, family);
 354
 355                         if (redir->target == FW3_TARGET_DNAT)
 356                         {
 357                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_dest);
 358                                 fw3_format_sport_dport(&redir->port_src, &redir->port_dest);
 359                         }
 360                         else
 361                         {
 362                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 363                                 fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 364                         }
 365
 366                         fw3_format_mac(mac);
 367                         fw3_format_extra(redir->extra);
 368                         fw3_format_comment(redir->name);
 369                         print_target_nat(redir);
 370                 }
 371                 else if (table == FW3_TABLE_FILTER)
 372                 {
 373                         print_chain_filter(redir);
 374                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 375                         fw3_format_protocol(proto, family);
 376                         fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 377                         fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 378                         fw3_format_mac(mac);
 379                         fw3_format_extra(redir->extra);
 380                         fw3_format_comment(redir->name);
 381                         print_target_filter(redir);
 382                 }
 383         }
 384
 385         /* reflection rules */
 386         if (redir->target != FW3_TARGET_DNAT || !redir->reflection)
 387                 return;
 388
 389         if (!redir->_dest || !redir->_src->masq)
 390                 return;
 391
 392         list_for_each_entry(ext_net, &redir->_src->networks, list)
 393         {
 394                 ext_addrs = fw3_ubus_address(ext_net->name);
 395
 396                 if (!ext_addrs || list_empty(ext_addrs))
 397                         continue;
 398
 399                 list_for_each_entry(int_net, &redir->_dest->networks, list)
 400                 {
 401                         int_addrs = fw3_ubus_address(int_net->name);
 402
 403                         if (!int_addrs || list_empty(int_addrs))
 404                                 continue;
 405
 406                         fw3_foreach(ext_addr, ext_addrs)
 407                         fw3_foreach(int_addr, int_addrs)
 408                         fw3_foreach(proto, &redir->proto)
 409                         {
 410                                 if (!fw3_is_family(int_addr, family) ||
 411                                     !fw3_is_family(ext_addr, family))
 412                                         continue;
 413
 414                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 415                                         continue;
 416
 417                                 ext_addr->mask = 32;
 418
 419                                 if (table == FW3_TABLE_NAT)
 420                                 {
 421                                         fw3_pr("-A zone_%s_prerouting", redir->dest.name);
 422                                         fw3_format_protocol(proto, family);
 423                                         fw3_format_src_dest(int_addr, ext_addr);
 424                                         fw3_format_sport_dport(NULL, &redir->port_dest);
 425                                         fw3_format_comment(redir->name, " (reflection)");
 426                                         print_snat_dnat(FW3_TARGET_DNAT,
 427                                                         &redir->ip_redir, &redir->port_redir);
 428
 429                                         fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 430                                         fw3_format_protocol(proto, family);
 431                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 432                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 433                                         fw3_format_comment(redir->name, " (reflection)");
 434                                         print_snat_dnat(FW3_TARGET_SNAT, ext_addr, NULL);
 435                                 }
 436                                 else if (table == FW3_TABLE_FILTER)
 437                                 {
 438                                         fw3_pr("-A zone_%s_forward", redir->dest.name);
 439                                         fw3_format_protocol(proto, family);
 440                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 441                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 442                                         fw3_format_comment(redir->name, " (reflection)");
 443                                         fw3_pr(" -j zone_%s_dest_ACCEPT\n", redir->dest.name);
 444                                 }
 445                         }
 446
 447                         fw3_ubus_address_free(int_addrs);
 448                 }
 449
 450                 fw3_ubus_address_free(ext_addrs);
 451         }
 452 }
 453
 454 void
 455 fw3_print_redirects(enum fw3_table table, enum fw3_family family,
 456                     struct fw3_state *state)
 457 {
 458         int num = 0;
 459         struct fw3_redirect *redir;
 460
 461         if (family == FW3_FAMILY_V6)
 462                 return;
 463
 464         if (table != FW3_TABLE_FILTER && table != FW3_TABLE_NAT)
 465                 return;
 466
 467         list_for_each_entry(redir, &state->redirects, list)
 468                 print_redirect(table, family, redir, num++);
 469 }