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