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("utc_time",            bool,      redirect,     time.utc),
  46         FW3_OPT("start_date",          date,      redirect,     time.datestart),
  47         FW3_OPT("stop_date",           date,      redirect,     time.datestop),
  48         FW3_OPT("start_time",          time,      redirect,     time.timestart),
  49         FW3_OPT("stop_time",           time,      redirect,     time.timestop),
  50         FW3_OPT("weekdays",            weekdays,  redirect,     time.weekdays),
  51         FW3_OPT("monthdays",           monthdays, redirect,     time.monthdays),
  52
  53         FW3_OPT("reflection",          bool,      redirect,     reflection),
  54
  55         FW3_OPT("target",              target,    redirect,     target),
  56
  57         { }
  58 };
  59
  60
  61 static bool
  62 check_families(struct uci_element *e, struct fw3_redirect *r)
  63 {
  64         if (r->family == FW3_FAMILY_ANY)
  65                 return true;
  66
  67         if (r->_src && r->_src->family && r->_src->family != r->family)
  68         {
  69                 warn_elem(e, "refers to source zone with different family");
  70                 return false;
  71         }
  72
  73         if (r->_dest && r->_dest->family && r->_dest->family != r->family)
  74         {
  75                 warn_elem(e, "refers to destination zone with different family");
  76                 return false;
  77         }
  78
  79         if (r->_ipset && r->_ipset->family && r->_ipset->family != r->family)
  80         {
  81                 warn_elem(e, "refers to ipset with different family");
  82                 return false;
  83         }
  84
  85         if (r->ip_src.family && r->ip_src.family != r->family)
  86         {
  87                 warn_elem(e, "uses source ip with different family");
  88                 return false;
  89         }
  90
  91         if (r->ip_dest.family && r->ip_dest.family != r->family)
  92         {
  93                 warn_elem(e, "uses destination ip with different family");
  94                 return false;
  95         }
  96
  97         if (r->ip_redir.family && r->ip_redir.family != r->family)
  98         {
  99                 warn_elem(e, "uses redirect ip with different family");
 100                 return false;
 101         }
 102
 103         return true;
 104 }
 105
 106 void
 107 fw3_load_redirects(struct fw3_state *state, struct uci_package *p)
 108 {
 109         struct uci_section *s;
 110         struct uci_element *e;
 111         struct fw3_redirect *redir;
 112
 113         bool valid = false;
 114
 115         INIT_LIST_HEAD(&state->redirects);
 116
 117         uci_foreach_element(&p->sections, e)
 118         {
 119                 s = uci_to_section(e);
 120
 121                 if (strcmp(s->type, "redirect"))
 122                         continue;
 123
 124                 redir = malloc(sizeof(*redir));
 125
 126                 if (!redir)
 127                         continue;
 128
 129                 memset(redir, 0, sizeof(*redir));
 130
 131                 INIT_LIST_HEAD(&redir->proto);
 132                 INIT_LIST_HEAD(&redir->mac_src);
 133
 134                 redir->reflection = true;
 135
 136                 fw3_parse_options(redir, fw3_redirect_opts, s);
 137
 138                 if (redir->src.invert)
 139                 {
 140                         warn_elem(e, "must not have an inverted source");
 141                         fw3_free_redirect(redir);
 142                         continue;
 143                 }
 144                 else if (redir->src.set && !redir->src.any &&
 145                          !(redir->_src = fw3_lookup_zone(state, redir->src.name, false)))
 146                 {
 147                         warn_elem(e, "refers to not existing zone '%s'", redir->src.name);
 148                         fw3_free_redirect(redir);
 149                         continue;
 150                 }
 151                 else if (redir->dest.set && !redir->dest.any &&
 152                          !(redir->_dest = fw3_lookup_zone(state, redir->dest.name, false)))
 153                 {
 154                         warn_elem(e, "refers to not existing zone '%s'", redir->dest.name);
 155                         fw3_free_redirect(redir);
 156                         continue;
 157                 }
 158                 else if (redir->ipset.set && state->disable_ipsets)
 159                 {
 160                         warn_elem(e, "skipped due to disabled ipset support");
 161                         fw3_free_redirect(redir);
 162                         continue;
 163                 }
 164                 else if (redir->ipset.set && !redir->ipset.any &&
 165                          !(redir->_ipset = fw3_lookup_ipset(state, redir->ipset.name, false)))
 166                 {
 167                         warn_elem(e, "refers to unknown ipset '%s'", redir->ipset.name);
 168                         fw3_free_redirect(redir);
 169                         continue;
 170                 }
 171
 172                 if (!check_families(e, redir))
 173                 {
 174                         fw3_free_redirect(redir);
 175                         continue;
 176                 }
 177
 178                 if (redir->target == FW3_TARGET_UNSPEC)
 179                 {
 180                         warn_elem(e, "has no target specified, defaulting to DNAT");
 181                         redir->target = FW3_TARGET_DNAT;
 182                 }
 183                 else if (redir->target < FW3_TARGET_DNAT)
 184                 {
 185                         warn_elem(e, "has invalid target specified, defaulting to DNAT");
 186                         redir->target = FW3_TARGET_DNAT;
 187                 }
 188
 189                 if (redir->target == FW3_TARGET_DNAT)
 190                 {
 191                         if (redir->src.any)
 192                                 warn_elem(e, "must not have source '*' for DNAT target");
 193                         else if (!redir->_src)
 194                                 warn_elem(e, "has no source specified");
 195                         else
 196                         {
 197                                 setbit(redir->_src->dst_flags, redir->target);
 198                                 redir->_src->conntrack = true;
 199                                 valid = true;
 200                         }
 201
 202                         if (redir->reflection && redir->_dest && redir->_src->masq)
 203                         {
 204                                 setbit(redir->_dest->dst_flags, FW3_TARGET_ACCEPT);
 205                                 setbit(redir->_dest->dst_flags, FW3_TARGET_DNAT);
 206                                 setbit(redir->_dest->dst_flags, FW3_TARGET_SNAT);
 207                         }
 208                 }
 209                 else
 210                 {
 211                         if (redir->dest.any)
 212                                 warn_elem(e, "must not have destination '*' for SNAT target");
 213                         else if (!redir->_dest)
 214                                 warn_elem(e, "has no destination specified");
 215                         else if (!redir->ip_dest.set)
 216                                 warn_elem(e, "has no src_dip option specified");
 217                         else
 218                         {
 219                                 setbit(redir->_dest->dst_flags, redir->target);
 220                                 redir->_dest->conntrack = true;
 221                                 valid = true;
 222                         }
 223                 }
 224
 225                 if (!valid)
 226                 {
 227                         fw3_free_redirect(redir);
 228                         continue;
 229                 }
 230
 231                 if (!redir->port_redir.set)
 232                         redir->port_redir = redir->port_dest;
 233
 234                 list_add_tail(&redir->list, &state->redirects);
 235         }
 236 }
 237
 238 static void
 239 print_chain_nat(struct fw3_redirect *redir)
 240 {
 241         if (redir->target == FW3_TARGET_DNAT)
 242                 fw3_pr("-A zone_%s_prerouting", redir->src.name);
 243         else
 244                 fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 245 }
 246
 247 static void
 248 print_snat_dnat(enum fw3_target target,
 249                 struct fw3_address *addr, struct fw3_port *port)
 250 {
 251         const char *t;
 252         char s[sizeof("255.255.255.255 ")];
 253
 254         if (target == FW3_TARGET_DNAT)
 255                 t = "DNAT --to-destination";
 256         else
 257                 t = "SNAT --to-source";
 258
 259         inet_ntop(AF_INET, &addr->address.v4, s, sizeof(s));
 260
 261         fw3_pr(" -j %s %s", t, s);
 262
 263         if (port && port->set)
 264         {
 265                 if (port->port_min == port->port_max)
 266                         fw3_pr(":%u", port->port_min);
 267                 else
 268                         fw3_pr(":%u-%u", port->port_min, port->port_max);
 269         }
 270
 271         fw3_pr("\n");
 272 }
 273
 274 static void
 275 print_target_nat(struct fw3_redirect *redir)
 276 {
 277         if (redir->target == FW3_TARGET_DNAT)
 278                 print_snat_dnat(redir->target, &redir->ip_redir, &redir->port_redir);
 279         else
 280                 print_snat_dnat(redir->target, &redir->ip_dest, &redir->port_dest);
 281 }
 282
 283 static void
 284 print_chain_filter(struct fw3_redirect *redir)
 285 {
 286         if (redir->target == FW3_TARGET_DNAT)
 287         {
 288                 /* XXX: check for local ip */
 289                 if (!redir->ip_redir.set)
 290                         fw3_pr("-A zone_%s_input", redir->src.name);
 291                 else
 292                         fw3_pr("-A zone_%s_forward", redir->src.name);
 293         }
 294         else
 295         {
 296                 if (redir->src.set && !redir->src.any)
 297                         fw3_pr("-A zone_%s_forward", redir->src.name);
 298                 else
 299                         fw3_pr("-A delegate_forward");
 300         }
 301 }
 302
 303 static void
 304 print_target_filter(struct fw3_redirect *redir)
 305 {
 306         /* XXX: check for local ip */
 307         if (redir->target == FW3_TARGET_DNAT && !redir->ip_redir.set)
 308                 fw3_pr(" -m conntrack --ctstate DNAT -j ACCEPT\n");
 309         else
 310                 fw3_pr(" -j ACCEPT\n");
 311 }
 312
 313 static void
 314 print_redirect(enum fw3_table table, enum fw3_family family,
 315                struct fw3_redirect *redir, int num)
 316 {
 317         struct list_head *ext_addrs, *int_addrs;
 318         struct fw3_address *ext_addr, *int_addr;
 319         struct fw3_device *ext_net, *int_net;
 320         struct fw3_protocol *proto;
 321         struct fw3_mac *mac;
 322
 323         if (redir->name)
 324                 info("   * Redirect '%s'", redir->name);
 325         else
 326                 info("   * Redirect #%u", num);
 327
 328         if (!fw3_is_family(redir->_src, family) ||
 329                 !fw3_is_family(redir->_dest, family))
 330         {
 331                 info("     ! Skipping due to different family of zone");
 332                 return;
 333         }
 334
 335         if (!fw3_is_family(&redir->ip_src, family) ||
 336             !fw3_is_family(&redir->ip_dest, family) ||
 337                 !fw3_is_family(&redir->ip_redir, family))
 338         {
 339                 info("     ! Skipping due to different family of ip address");
 340                 return;
 341         }
 342
 343         if (redir->_ipset)
 344         {
 345                 if (!fw3_is_family(redir->_ipset, family))
 346                 {
 347                         info("     ! Skipping due to different family in ipset");
 348                         return;
 349                 }
 350
 351                 setbit(redir->_ipset->flags, family);
 352         }
 353
 354         fw3_foreach(proto, &redir->proto)
 355         fw3_foreach(mac, &redir->mac_src)
 356         {
 357                 if (table == FW3_TABLE_NAT)
 358                 {
 359                         print_chain_nat(redir);
 360                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 361                         fw3_format_protocol(proto, family);
 362
 363                         if (redir->target == FW3_TARGET_DNAT)
 364                         {
 365                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_dest);
 366                                 fw3_format_sport_dport(&redir->port_src, &redir->port_dest);
 367                         }
 368                         else
 369                         {
 370                                 fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 371                                 fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 372                         }
 373
 374                         fw3_format_mac(mac);
 375                         fw3_format_time(&redir->time);
 376                         fw3_format_extra(redir->extra);
 377                         fw3_format_comment(redir->name);
 378                         print_target_nat(redir);
 379                 }
 380                 else if (table == FW3_TABLE_FILTER)
 381                 {
 382                         print_chain_filter(redir);
 383                         fw3_format_ipset(redir->_ipset, redir->ipset.invert);
 384                         fw3_format_protocol(proto, family);
 385                         fw3_format_src_dest(&redir->ip_src, &redir->ip_redir);
 386                         fw3_format_sport_dport(&redir->port_src, &redir->port_redir);
 387                         fw3_format_mac(mac);
 388                         fw3_format_time(&redir->time);
 389                         fw3_format_extra(redir->extra);
 390                         fw3_format_comment(redir->name);
 391                         print_target_filter(redir);
 392                 }
 393         }
 394
 395         /* reflection rules */
 396         if (redir->target != FW3_TARGET_DNAT || !redir->reflection)
 397                 return;
 398
 399         if (!redir->_dest || !redir->_src->masq)
 400                 return;
 401
 402         list_for_each_entry(ext_net, &redir->_src->networks, list)
 403         {
 404                 ext_addrs = fw3_ubus_address(ext_net->name);
 405
 406                 if (!ext_addrs || list_empty(ext_addrs))
 407                         continue;
 408
 409                 list_for_each_entry(int_net, &redir->_dest->networks, list)
 410                 {
 411                         int_addrs = fw3_ubus_address(int_net->name);
 412
 413                         if (!int_addrs || list_empty(int_addrs))
 414                                 continue;
 415
 416                         fw3_foreach(ext_addr, ext_addrs)
 417                         fw3_foreach(int_addr, int_addrs)
 418                         fw3_foreach(proto, &redir->proto)
 419                         {
 420                                 if (!fw3_is_family(int_addr, family) ||
 421                                     !fw3_is_family(ext_addr, family))
 422                                         continue;
 423
 424                                 if (!proto || (proto->protocol != 6 && proto->protocol != 17))
 425                                         continue;
 426
 427                                 ext_addr->mask = 32;
 428
 429                                 if (table == FW3_TABLE_NAT)
 430                                 {
 431                                         fw3_pr("-A zone_%s_prerouting", redir->dest.name);
 432                                         fw3_format_protocol(proto, family);
 433                                         fw3_format_src_dest(int_addr, ext_addr);
 434                                         fw3_format_sport_dport(NULL, &redir->port_dest);
 435                                         fw3_format_time(&redir->time);
 436                                         fw3_format_comment(redir->name, " (reflection)");
 437                                         print_snat_dnat(FW3_TARGET_DNAT,
 438                                                         &redir->ip_redir, &redir->port_redir);
 439
 440                                         fw3_pr("-A zone_%s_postrouting", redir->dest.name);
 441                                         fw3_format_protocol(proto, family);
 442                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 443                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 444                                         fw3_format_time(&redir->time);
 445                                         fw3_format_comment(redir->name, " (reflection)");
 446                                         print_snat_dnat(FW3_TARGET_SNAT, ext_addr, NULL);
 447                                 }
 448                                 else if (table == FW3_TABLE_FILTER)
 449                                 {
 450                                         fw3_pr("-A zone_%s_forward", redir->dest.name);
 451                                         fw3_format_protocol(proto, family);
 452                                         fw3_format_src_dest(int_addr, &redir->ip_redir);
 453                                         fw3_format_sport_dport(NULL, &redir->port_redir);
 454                                         fw3_format_time(&redir->time);
 455                                         fw3_format_comment(redir->name, " (reflection)");
 456                                         fw3_pr(" -j zone_%s_dest_ACCEPT\n", redir->dest.name);
 457                                 }
 458                         }
 459
 460                         fw3_ubus_address_free(int_addrs);
 461                 }
 462
 463                 fw3_ubus_address_free(ext_addrs);
 464         }
 465 }
 466
 467 void
 468 fw3_print_redirects(enum fw3_table table, enum fw3_family family,
 469                     struct fw3_state *state)
 470 {
 471         int num = 0;
 472         struct fw3_redirect *redir;
 473
 474         if (family == FW3_FAMILY_V6)
 475                 return;
 476
 477         if (table != FW3_TABLE_FILTER && table != FW3_TABLE_NAT)
 478                 return;
 479
 480         list_for_each_entry(redir, &state->redirects, list)
 481                 print_redirect(table, family, redir, num++);
 482 }