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 static struct fw3_option 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 static bool
  52 check_families(struct uci_element *e, struct fw3_redirect *r)
  53 {
  54         if (r->family == FW3_FAMILY_ANY)
  55                 return true;
  56
  57         if (r->_src && r->_src->family && r->_src->family != r->family)
  58         {
  59                 warn_elem(e, "refers to source zone with different family");
  60                 return false;
  61         }
  62
  63         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  64         {
  65                 warn_elem(e, "refers to destination zone with different family");
  66                 return false;
  67         }
  68
  69         if (r->_ipset && r->_ipset->family && r->_ipset->family != r->family)
  70         {
  71                 warn_elem(e, "refers to ipset with different family");
  72                 return false;
  73         }
  74
  75         if (r->ip_src.family && r->ip_src.family != r->family)
  76         {
  77                 warn_elem(e, "uses source ip with different family");
  78                 return false;
  79         }
  80
  81         if (r->ip_dest.family && r->ip_dest.family != r->family)
  82         {
  83                 warn_elem(e, "uses destination ip with different family");
  84                 return false;
  85         }
  86
  87         if (r->ip_redir.family && r->ip_redir.family != r->family)
  88         {
  89                 warn_elem(e, "uses redirect ip with different family");
  90                 return false;
  91         }
  92
  93         return true;
  94 }
  95
  96 void
  97 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
  98 {
  99         struct uci_section *s;
 100         struct uci_element *e;
 101         struct fw3_redirect *redir;
 102
 103         bool valid = false;
 104
 105         INIT_LIST_HEAD(&state->redirects);
 106
 107         uci_foreach_element(&p->sections, e)
 108         {
 109                 s = uci_to_section(e);
 110
 111                 if (strcmp(s->type, "redirect"))
 112                         continue;
 113
 114                 redir = malloc(sizeof(*redir));
 115
 116                 if (!redir)
 117                         continue;
 118
 119                 memset(redir, 0, sizeof(*redir));
 120
 121                 INIT_LIST_HEAD(&redir->proto);
 122                 INIT_LIST_HEAD(&redir->mac_src);
 123
 124                 redir->reflection = true;
 125
 126                 fw3_parse_options(redir, redirect_opts, ARRAY_SIZE(redirect_opts), s);
 127
 128                 if (redir->src.invert)
 129                 {
 130                         warn_elem(e, "must not have an inverted source");
 131                         fw3_free_redirect(redir);
 132                         continue;
 133                 }
 134                 else if (redir->src.set && !redir->src.any &&
 135                          !(redir->_src = fw3_lookup_zone(state, redir->src.name, false)))
 136                 {
 137                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 138                         fw3_free_redirect(redir);
 139                         continue;
 140                 }
 141                 else if (redir->dest.set && !redir->dest.any &&
 142                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name, false)))
 143                 {
 144                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 145                         fw3_free_redirect(redir);
 146                         continue;
 147                 }
 148                 else if (redir->ipset.set && state->disable_ipsets)
 149                 {
 150                         warn_elem(e, "skipped due to disabled ipset support");
 151                         fw3_free_redirect(redir);
 152                         continue;
 153                 }
 154                 else if (redir->ipset.set && !redir->ipset.any &&
 155                          !(redir->_ipset = fw3_lookup_ipset(state, redir->ipset.name, false)))
 156                 {
 157                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 158                         fw3_free_redirect(redir);
 159                         continue;
 160                 }
 161
 162                 if (!check_families(e, redir))
 163                 {
 164                         fw3_free_redirect(redir);
 165                         continue;
 166                 }
 167
 168                 if (redir->target == FW3_TARGET_UNSPEC)
 169                 {
 170                         warn_elem(e, "has no target specified, defaulting to DNAT");
 171                         redir->target = FW3_TARGET_DNAT;
 172                 }
 173                 else if (redir->target < FW3_TARGET_DNAT)
 174                 {
 175                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 176                         redir->target = FW3_TARGET_DNAT;
 177                 }
 178
 179                 if (redir->target == FW3_TARGET_DNAT)
 180                 {
 181                         if (redir->src.any)
 182                                 warn_elem(e, "must not have source '*' for DNAT target");
 183                         else if (!redir->_src)
 184                                 warn_elem(e, "has no source specified");
 185                         else
 186                         {
 187                                 setbit(redir->_src->dst_flags, redir->target);
 188                                 redir->_src->conntrack = true;
 189                                 valid = true;
 190                         }
 191
 192                         if (redir->reflection && redir->_dest && redir->_src->masq)
 193                         {
 194                                 setbit(redir->_dest->dst_flags, FW3_TARGET_ACCEPT);
 195                                 setbit(redir->_dest->dst_flags, FW3_TARGET_DNAT);
 196                                 setbit(redir->_dest->dst_flags, FW3_TARGET_SNAT);
 197                         }
 198                 }
 199                 else
 200                 {
 201                         if (redir->dest.any)
 202                                 warn_elem(e, "must not have destination '*' for SNAT target");
 203                         else if (!redir->_dest)
 204                                 warn_elem(e, "has no destination specified");
 205                         else if (!redir->ip_dest.set)
 206                                 warn_elem(e, "has no src_dip option specified");
 207                         else
 208                         {
 209                                 setbit(redir->_dest->dst_flags, redir->target);
 210                                 redir->_dest->conntrack = true;
 211                                 valid = true;
 212                         }
 213                 }
 214
 215                 if (!valid)
 216                 {
 217                         fw3_free_redirect(redir);
 218                         continue;
 219                 }
 220
 221                 if (!redir->port_redir.set)
 222                         redir->port_redir = redir->port_dest;
 223
 224                 list_add_tail(&redir->list, &state->redirects);
 225         }
 226 }
 227
 228 static void
 229 print_chain_nat(struct fw3_redirect *redir)
 230 {
 231         if (redir->target == FW3_TARGET_DNAT)
 232                 fw3_pr("-A zone_%s_prerouting", redir->src.name);
 233         else
 234                 fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 235 }
 236
 237 static void
 238 print_snat_dnat(enum fw3_target target,
 239                 struct fw3_address *addr, struct fw3_port *port)
 240 {
 241         const char *t;
 242         char s[sizeof("255.255.255.255 ")];
 243
 244         if (target == FW3_TARGET_DNAT)
 245                 t = "DNAT --to-destination";
 246         else
 247                 t = "SNAT --to-source";
 248
 249         inet_ntop(AF_INET, &addr->address.v4, s, sizeof(s));
 250
 251         fw3_pr(" -j %s %s", t, s);
 252
 253         if (port && port->set)
 254         {
 255                 if (port->port_min == port->port_max)
 256                         fw3_pr(":%u", port->port_min);
 257                 else
 258                         fw3_pr(":%u-%u", port->port_min, port->port_max);
 259         }
 260
 261         fw3_pr("\n");
 262 }
 263
 264 static void
 265 print_target_nat(struct fw3_redirect *redir)
 266 {
 267         if (redir->target == FW3_TARGET_DNAT)
 268                 print_snat_dnat(redir->target, &redir->ip_redir, &redir->port_redir);
 269         else
 270                 print_snat_dnat(redir->target, &redir->ip_dest, &redir->port_dest);
 271 }
 272
 273 static void
 274 print_chain_filter(struct fw3_redirect *redir)
 275 {
 276         if (redir->target == FW3_TARGET_DNAT)
 277         {
 278                 /* XXX: check for local ip */
 279                 if (!redir->ip_redir.set)
 280                         fw3_pr("-A zone_%s_input", redir->src.name);
 281                 else
 282                         fw3_pr("-A zone_%s_forward", redir->src.name);
 283         }
 284         else
 285         {
 286                 if (redir->src.set && !redir->src.any)
 287                         fw3_pr("-A zone_%s_forward", redir->src.name);
 288                 else
 289                         fw3_pr("-A delegate_forward");
 290         }
 291 }
 292
 293 static void
 294 print_target_filter(struct fw3_redirect *redir)
 295 {
 296         /* XXX: check for local ip */
 297         if (redir->target == FW3_TARGET_DNAT && !redir->ip_redir.set)
 298                 fw3_pr(" -m conntrack --ctstate DNAT -j ACCEPT\n");
 299         else
 300                 fw3_pr(" -j ACCEPT\n");
 301 }
 302
 303 static void
 304 print_redirect(enum fw3_table table, enum fw3_family family,
 305                struct fw3_redirect *redir, int num)
 306 {
 307         struct list_head *ext_addrs, *int_addrs;
 308         struct fw3_address *ext_addr, *int_addr;
 309         struct fw3_device *ext_net, *int_net;
 310         struct fw3_protocol *proto;
 311         struct fw3_mac *mac;
 312
 313         if (redir->name)
 314                 info("   * Redirect '%s'", redir->name);
 315         else
 316                 info("   * Redirect #%u", num);
 317
 318         if (!fw3_is_family(redir->_src, family) ||
 319                 !fw3_is_family(redir->_dest, family))
 320         {
 321                 info("     ! Skipping due to different family of zone");
 322                 return;
 323         }
 324
 325         if (!fw3_is_family(&redir->ip_src, family) ||
 326             !fw3_is_family(&redir->ip_dest, family) ||
 327                 !fw3_is_family(&redir->ip_redir, family))
 328         {
 329                 info("     ! Skipping due to different family of ip address");
 330                 return;
 331         }
 332
 333         if (redir->_ipset)
 334         {
 335                 if (!fw3_is_family(redir->_ipset, family))
 336                 {
 337                         info("     ! Skipping due to different family in ipset");
 338                         return;
 339                 }
 340
 341                 setbit(redir->_ipset->flags, family);
 342         }
 343
 344         fw3_foreach(proto, &redir->proto)
 345         fw3_foreach(mac, &redir->mac_src)
 346         {
 347                 if (table == FW3_TABLE_NAT)
 348                 {
 349                         print_chain_nat(redir);
 350                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 351                         fw3_format_protocol(proto, family);
 352
 353                         if (redir->target == FW3_TARGET_DNAT)
 354                         {
 355                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_dest);
 356                                 fw3_format_sport_dport(&redir->port_src, &redir->port_dest);
 357                         }
 358                         else
 359                         {
 360                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 361                                 fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 362                         }
 363
 364                         fw3_format_mac(mac);
 365                         fw3_format_extra(redir->extra);
 366                         fw3_format_comment(redir->name);
 367                         print_target_nat(redir);
 368                 }
 369                 else if (table == FW3_TABLE_FILTER)
 370                 {
 371                         print_chain_filter(redir);
 372                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 373                         fw3_format_protocol(proto, family);
 374                         fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 375                         fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 376                         fw3_format_mac(mac);
 377                         fw3_format_extra(redir->extra);
 378                         fw3_format_comment(redir->name);
 379                         print_target_filter(redir);
 380                 }
 381         }
 382
 383         /* reflection rules */
 384         if (redir->target != FW3_TARGET_DNAT || !redir->reflection)
 385                 return;
 386
 387         if (!redir->_dest || !redir->_src->masq)
 388                 return;
 389
 390         list_for_each_entry(ext_net, &redir->_src->networks, list)
 391         {
 392                 ext_addrs = fw3_ubus_address(ext_net->name);
 393
 394                 if (!ext_addrs || list_empty(ext_addrs))
 395                         continue;
 396
 397                 list_for_each_entry(int_net, &redir->_dest->networks, list)
 398                 {
 399                         int_addrs = fw3_ubus_address(int_net->name);
 400
 401                         if (!int_addrs || list_empty(int_addrs))
 402                                 continue;
 403
 404                         fw3_foreach(ext_addr, ext_addrs)
 405                         fw3_foreach(int_addr, int_addrs)
 406                         fw3_foreach(proto, &redir->proto)
 407                         {
 408                                 if (!fw3_is_family(int_addr, family) ||
 409                                     !fw3_is_family(ext_addr, family))
 410                                         continue;
 411
 412                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 413                                         continue;
 414
 415                                 ext_addr->mask = 32;
 416
 417                                 if (table == FW3_TABLE_NAT)
 418                                 {
 419                                         fw3_pr("-A zone_%s_prerouting", redir->dest.name);
 420                                         fw3_format_protocol(proto, family);
 421                                         fw3_format_src_dest(int_addr, ext_addr);
 422                                         fw3_format_sport_dport(NULL, &redir->port_dest);
 423                                         fw3_format_comment(redir->name, " (reflection)");
 424                                         print_snat_dnat(FW3_TARGET_DNAT,
 425                                                         &redir->ip_redir, &redir->port_redir);
 426
 427                                         fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 428                                         fw3_format_protocol(proto, family);
 429                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 430                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 431                                         fw3_format_comment(redir->name, " (reflection)");
 432                                         print_snat_dnat(FW3_TARGET_SNAT, ext_addr, NULL);
 433                                 }
 434                                 else if (table == FW3_TABLE_FILTER)
 435                                 {
 436                                         fw3_pr("-A zone_%s_forward", redir->dest.name);
 437                                         fw3_format_protocol(proto, family);
 438                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 439                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 440                                         fw3_format_comment(redir->name, " (reflection)");
 441                                         fw3_pr(" -j zone_%s_dest_ACCEPT\n", redir->dest.name);
 442                                 }
 443                         }
 444
 445                         fw3_ubus_address_free(int_addrs);
 446                 }
 447
 448                 fw3_ubus_address_free(ext_addrs);
 449         }
 450 }
 451
 452 void
 453 fw3_print_redirects(enum fw3_table table, enum fw3_family family,
 454                     struct fw3_state *state)
 455 {
 456         int num = 0;
 457         struct fw3_redirect *redir;
 458
 459         if (family == FW3_FAMILY_V6)
 460                 return;
 461
 462         if (table != FW3_TABLE_FILTER && table != FW3_TABLE_NAT)
 463                 return;
 464
 465         list_for_each_entry(redir, &state->redirects, list)
 466                 print_redirect(table, family, redir, num++);
 467 }
 468
 469 void
 470 fw3_free_redirect(struct fw3_redirect *redir)
 471 {
 472         fw3_free_list(&redir->proto);
 473         fw3_free_list(&redir->mac_src);
 474         free(redir);
 475 }