contrib/fwd/src/fwd_rules.c

   1 /*
   2  * fwd - OpenWrt firewall daemon - iptables rule set
   3  *
   4  *   Copyright (C) 2009 Jo-Philipp Wich <xm@subsignal.org>
   5  *
   6  * The fwd program is free software: you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License version 2
   8  * as published by the Free Software Foundation.
   9  *
  10  * The fwd program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with the fwd program. If not, see http://www.gnu.org/licenses/.
  17  */
  18
  19
  20 #include "fwd.h"
  21 #include "fwd_addr.h"
  22 #include "fwd_rules.h"
  23 #include "fwd_xtables.h"
  24
  25
  26 /* -P <chain> <policy> */
  27 static void fwd_r_set_policy(
  28         struct iptc_handle *h, const char *chain, const char *policy
  29 ) {
  30         iptc_set_policy(chain, policy, NULL, h);
  31 }
  32
  33 /* -N <chain> */
  34 static void fwd_r_new_chain(struct iptc_handle *h, const char *chain)
  35 {
  36         iptc_create_chain(chain, h);
  37 }
  38
  39 /* -A <chain1> -j <chain2> */
  40 static void fwd_r_jump_chain(
  41         struct iptc_handle *h, const char *chain1, const char *chain2
  42 ) {
  43         struct fwd_xt_rule *r;
  44
  45         if( (r = fwd_xt_init_rule(h)) != NULL )
  46         {
  47                 fwd_xt_get_target(r, chain2);
  48                 fwd_xt_append_rule(r, chain1);
  49         }
  50 }
  51
  52 /* -A <chain> -m state --state INVALID -j DROP */
  53 static void fwd_r_drop_invalid(struct iptc_handle *h, const char *chain)
  54 {
  55         struct fwd_xt_rule *r;
  56         struct xtables_match *m;
  57
  58         if( (r = fwd_xt_init_rule(h)) != NULL )
  59         {
  60                 if( (m = fwd_xt_get_match(r, "state")) != NULL )
  61                 {
  62                         fwd_xt_parse_match(r, m, "--state", "INVALID");
  63                         fwd_xt_get_target(r, "DROP");
  64                         fwd_xt_append_rule(r, chain);
  65                 }
  66         }
  67 }
  68
  69 /* -A <chain> -m state --state RELATED,ESTABLISHED -j ACCEPT */
  70 static void fwd_r_accept_related(struct iptc_handle *h, const char *chain)
  71 {
  72         struct fwd_xt_rule *r;
  73         struct xtables_match *m;
  74
  75         if( (r = fwd_xt_init_rule(h)) != NULL )
  76         {
  77                 if( (m = fwd_xt_get_match(r, "state")) != NULL )
  78                 {
  79                         fwd_xt_parse_match(r, m, "--state", "RELATED,ESTABLISHED");
  80                         fwd_xt_get_target(r, "ACCEPT");
  81                         fwd_xt_append_rule(r, chain);
  82                 }
  83         }
  84 }
  85
  86 /* -A INPUT -i lo -j ACCEPT; -A OUTPUT -o lo -j ACCEPT */
  87 static void fwd_r_accept_lo(struct iptc_handle *h)
  88 {
  89         struct fwd_network_list n;
  90         struct fwd_xt_rule *r;
  91
  92         n.ifname = "lo";
  93
  94         if( (r = fwd_xt_init_rule(h)) != NULL )
  95         {
  96                 fwd_xt_parse_in(r, &n, 0);
  97                 fwd_xt_get_target(r, "ACCEPT");
  98                 fwd_xt_append_rule(r, "INPUT");
  99         }
 100
 101         if( (r = fwd_xt_init_rule(h)) != NULL )
 102         {
 103                 fwd_xt_parse_out(r, &n, 0);
 104                 fwd_xt_get_target(r, "ACCEPT");
 105                 fwd_xt_append_rule(r, "OUTPUT");
 106         }
 107 }
 108
 109 /* build syn_flood chain and jump rule */
 110 static void fwd_r_add_synflood(struct iptc_handle *h, struct fwd_defaults *def)
 111 {
 112         struct fwd_proto p;
 113         struct fwd_xt_rule *r;
 114         struct xtables_match *m;
 115         char buf[32];
 116
 117         /* -N syn_flood */
 118         fwd_r_new_chain(h, "syn_flood");
 119
 120         /* return rule */
 121         if( (r = fwd_xt_init_rule(h)) != NULL )
 122         {
 123                 /* -p tcp */
 124                 p.type = FWD_PR_TCP;
 125                 fwd_xt_parse_proto(r, &p, 0);
 126
 127                 /* -m tcp --syn */
 128                 if( (m = fwd_xt_get_match(r, "tcp")) != NULL )
 129                 {
 130                         fwd_xt_parse_match(r, m, "--syn");
 131                 }
 132
 133                 /* -m limit --limit x/second --limit-burst y */
 134                 if( (m = fwd_xt_get_match(r, "limit")) != NULL )
 135                 {
 136                         sprintf(buf, "%i/second", def->syn_rate);
 137                         fwd_xt_parse_match(r, m, "--limit", buf);
 138
 139                         sprintf(buf, "%i", def->syn_burst);
 140                         fwd_xt_parse_match(r, m, "--limit-burst", buf);
 141                 }
 142
 143                 /* -j RETURN; -A syn_flood */
 144                 fwd_xt_get_target(r, "RETURN");
 145                 fwd_xt_append_rule(r, "syn_flood");
 146         }
 147
 148         /* drop rule */
 149         if( (r = fwd_xt_init_rule(h)) != NULL )
 150         {
 151                 /* -j DROP; -A syn_flood */
 152                 fwd_xt_get_target(r, "DROP");
 153                 fwd_xt_append_rule(r, "syn_flood");
 154         }
 155
 156         /* jump to syn_flood rule */
 157         if( (r = fwd_xt_init_rule(h)) != NULL )
 158         {
 159                 /* -p tcp */
 160                 p.type = FWD_PR_TCP;
 161                 fwd_xt_parse_proto(r, &p, 0);
 162
 163                 /* -m tcp --syn */
 164                 if( (m = fwd_xt_get_match(r, "tcp")) != NULL )
 165                 {
 166                         fwd_xt_parse_match(r, m, "--syn");
 167                 }
 168
 169                 /* -j syn_flood; -A INPUT */
 170                 fwd_xt_get_target(r, "syn_flood");
 171                 fwd_xt_append_rule(r, "INPUT");
 172         }
 173 }
 174
 175 /* build reject target chain */
 176 static void fwd_r_handle_reject(struct iptc_handle *h)
 177 {
 178         struct fwd_proto p;
 179         struct fwd_xt_rule *r;
 180         struct xtables_target *t;
 181
 182         /* -N handle_reject */
 183         fwd_r_new_chain(h, "handle_reject");
 184
 185         /* tcp reject rule */
 186         if( (r = fwd_xt_init_rule(h)) != NULL )
 187         {
 188                 /* -p tcp */
 189                 p.type = FWD_PR_TCP;
 190                 fwd_xt_parse_proto(r, &p, 0);
 191
 192                 /* -j REJECT --reject-with tcp-reset */
 193                 if( (t = fwd_xt_get_target(r, "REJECT")) != NULL )
 194                 {
 195                         fwd_xt_parse_target(r, t, "--reject-with", "tcp-reset");
 196                 }
 197
 198                 /* -A handle_reject */
 199                 fwd_xt_append_rule(r, "handle_reject");
 200         }
 201
 202         /* common reject rule */
 203         if( (r = fwd_xt_init_rule(h)) != NULL )
 204         {
 205                 /* -j REJECT --reject-with icmp-port-unreachable */
 206                 if( (t = fwd_xt_get_target(r, "REJECT")) != NULL )
 207                 {
 208                         fwd_xt_parse_target(r, t, "--reject-with",
 209                                 "icmp-port-unreachable");
 210                 }
 211
 212                 /* -A handle_reject */
 213                 fwd_xt_append_rule(r, "handle_reject");
 214         }
 215 }
 216
 217 /* build drop target chain */
 218 static void fwd_r_handle_drop(struct iptc_handle *h)
 219 {
 220         struct fwd_xt_rule *r;
 221
 222         /* -N handle_drop */
 223         fwd_r_new_chain(h, "handle_drop");
 224
 225         /* common drop rule */
 226         if( (r = fwd_xt_init_rule(h)) != NULL )
 227         {
 228                 /* -j DROP; -A handle_reject */
 229                 fwd_xt_get_target(r, "DROP");
 230                 fwd_xt_append_rule(r, "handle_reject");
 231         }
 232 }
 233
 234 /* build accept target chain */
 235 static void fwd_r_handle_accept(struct iptc_handle *h)
 236 {
 237         struct fwd_xt_rule *r;
 238
 239         /* -N handle_accept */
 240         fwd_r_new_chain(h, "handle_accept");
 241
 242         /* common accept rule */
 243         if( (r = fwd_xt_init_rule(h)) != NULL )
 244         {
 245                 /* -j ACCEPT; -A handle_accept */
 246                 fwd_xt_get_target(r, "ACCEPT");
 247                 fwd_xt_append_rule(r, "handle_accept");
 248         }
 249 }
 250
 251 /* add comment match */
 252 static void fwd_r_add_comment(
 253         struct fwd_xt_rule *r, const char *t, struct fwd_zone *z,
 254         struct fwd_network_list *n, struct fwd_network_list *n2
 255 ) {
 256         struct xtables_match *m;
 257         char buf[256];
 258
 259         if( (m = fwd_xt_get_match(r, "comment")) != NULL )
 260         {
 261                 if( (n != NULL) && (n2 != NULL) )
 262                         snprintf(buf, sizeof(buf), "%s:%s src:%s dest:%s",
 263                                 t, z->name, n->name, n2->name);
 264                 else if( (n == NULL) && (n2 != NULL) )
 265                         snprintf(buf, sizeof(buf), "%s:%s dest:%s", t, z->name, n2->name);
 266                 else
 267                         snprintf(buf, sizeof(buf), "%s:%s src:%s", t, z->name, n->name);
 268
 269                 fwd_xt_parse_match(r, m, "--comment", buf);
 270         }
 271 }
 272
 273 /* add --sport (if applicable) */
 274 static void fwd_r_add_sport(
 275         struct fwd_xt_rule *r, struct fwd_portrange *p
 276 ) {
 277         int proto = r->entry->ip.proto;
 278         char buf[12];
 279         struct xtables_match *m;
 280
 281         /* have portrange and proto is tcp or udp ... */
 282         if( (p != NULL) && ((proto == 6) || (proto == 17)) )
 283         {
 284                 /* get match ... */
 285                 if( (m = fwd_xt_get_match(r, (proto == 6) ? "tcp" : "udp")) != NULL )
 286                 {
 287                         snprintf(buf, sizeof(buf), "%u:%u", p->min, p->max);
 288                         fwd_xt_parse_match(r, m, "--sport", buf);
 289                 }
 290         }
 291 }
 292
 293 /* add --dport (if applicable) */
 294 static void fwd_r_add_dport(
 295         struct fwd_xt_rule *r, struct fwd_portrange *p
 296 ) {
 297         int proto = r->entry->ip.proto;
 298         char buf[12];
 299         struct xtables_match *m;
 300
 301         /* have portrange and proto is tcp or udp ... */
 302         if( (p != NULL) && ((proto == 6) || (proto == 17)) )
 303         {
 304                 /* get match ... */
 305                 if( (m = fwd_xt_get_match(r, (proto == 6) ? "tcp" : "udp")) != NULL )
 306                 {
 307                         snprintf(buf, sizeof(buf), "%u:%u", p->min, p->max);
 308                         fwd_xt_parse_match(r, m, "--dport", buf);
 309                 }
 310         }
 311 }
 312
 313 /* add --icmp-type (of applicable) */
 314 static void fwd_r_add_icmptype(
 315         struct fwd_xt_rule *r, struct fwd_icmptype *i
 316 ) {
 317         int proto = r->entry->ip.proto;
 318         struct xtables_match *m;
 319         char buf[32];
 320
 321         /* have icmp-type and proto is icmp ... */
 322         if( (i != NULL) && (proto == 1) )
 323         {
 324                 /* get match ... */
 325                 if( (m = fwd_xt_get_match(r, "icmp")) != NULL )
 326                 {
 327                         if( i->name[0] )
 328                                 snprintf(buf, sizeof(buf), "%s", i->name);
 329                         else
 330                                 snprintf(buf, sizeof(buf), "%u/%u", i->type, i->code);
 331
 332                         fwd_xt_parse_match(r, m, "--icmp-type", buf);
 333                 }
 334         }
 335 }
 336
 337 /* add -m mac --mac-source ... */
 338 static void fwd_r_add_srcmac(
 339         struct fwd_xt_rule *r, struct fwd_mac *mac
 340 ) {
 341         struct xtables_match *m;
 342         char buf[18];
 343
 344         if( mac != NULL )
 345         {
 346                 if( (m = fwd_xt_get_match(r, "mac")) != NULL )
 347                 {
 348                         snprintf(buf, sizeof(buf), "%02x:%02x:%02x:%02x:%02x:%02x",
 349                                 mac->mac[0], mac->mac[1], mac->mac[2],
 350                                 mac->mac[3], mac->mac[4], mac->mac[5]);
 351
 352                         fwd_xt_parse_match(r, m, "--mac-source", buf);
 353                 }
 354         }
 355 }
 356
 357 /* add policy target */
 358 static void fwd_r_add_policytarget(
 359         struct fwd_xt_rule *r, enum fwd_policy pol
 360 ) {
 361         switch(pol)
 362         {
 363                 case FWD_P_ACCEPT:
 364                         fwd_xt_get_target(r, "handle_accept");
 365                         break;
 366
 367                 case FWD_P_REJECT:
 368                         fwd_xt_get_target(r, "handle_reject");
 369                         break;
 370
 371                 case FWD_P_DROP:
 372                 case FWD_P_UNSPEC:
 373                         fwd_xt_get_target(r, "handle_drop");
 374                         break;
 375         }
 376 }
 377
 378 /* add dnat target */
 379 static void fwd_r_add_dnattarget(
 380         struct fwd_xt_rule *r, struct fwd_cidr *c, struct fwd_portrange *p
 381 ) {
 382         struct xtables_target *t;
 383         char buf[32];
 384
 385         if( c != NULL )
 386         {
 387                 if( (t = fwd_xt_get_target(r, "DNAT")) != NULL )
 388                 {
 389                         if( p != NULL )
 390                                 snprintf(buf, sizeof(buf), "%s:%u-%u",
 391                                         inet_ntoa(c->addr), p->min, p->max);
 392                         else
 393                                 snprintf(buf, sizeof(buf), "%s", inet_ntoa(c->addr));
 394
 395                         fwd_xt_parse_target(r, t, "--to-destination", buf);
 396                 }
 397         }
 398 }
 399
 400 /* parse comment string and look for match */
 401 static int fwd_r_cmp(const char *what, const char *cmt, const char *cmp)
 402 {
 403         char *match;
 404
 405         if( (match = strstr(cmt, what)) == NULL )
 406                 return 0;
 407
 408         match += strlen(what);
 409
 410         if( strncmp(match, cmp, strlen(cmp)) != 0 )
 411                 return 0;
 412
 413         if( (match[strlen(cmp)] != ' ') && (match[strlen(cmp)] != '\0') )
 414                 return 0;
 415
 416         return 1;
 417 }
 418
 419
 420 static void fwd_ipt_defaults_create(struct fwd_data *d)
 421 {
 422         struct fwd_defaults *def = &d->section.defaults;
 423         struct iptc_handle *h_filter, *h_nat;
 424
 425         if( !(h_filter = iptc_init("filter")) || !(h_nat = iptc_init("nat")) )
 426                 fwd_fatal("Unable to obtain libiptc handle");
 427
 428         /* policies */
 429         fwd_r_set_policy(h_filter, "INPUT",
 430                 def->input == FWD_P_ACCEPT ? "ACCEPT" : "DROP");
 431         fwd_r_set_policy(h_filter, "OUTPUT",
 432                 def->output == FWD_P_ACCEPT ? "ACCEPT" : "DROP");
 433         fwd_r_set_policy(h_filter, "FORWARD",
 434                 def->forward == FWD_P_ACCEPT ? "ACCEPT" : "DROP");
 435
 436         /* invalid state drop */
 437         if( def->drop_invalid )
 438         {
 439                 fwd_r_drop_invalid(h_filter, "INPUT");
 440                 fwd_r_drop_invalid(h_filter, "OUTPUT");
 441                 fwd_r_drop_invalid(h_filter, "FORWARD");
 442         }
 443
 444         /* default accept related */
 445         fwd_r_accept_related(h_filter, "INPUT");
 446         fwd_r_accept_related(h_filter, "OUTPUT");
 447         fwd_r_accept_related(h_filter, "FORWARD");
 448
 449         /* default accept on lo */
 450         fwd_r_accept_lo(h_filter);
 451
 452         /* syn flood protection */
 453         if( def->syn_flood )
 454         {
 455                 fwd_r_add_synflood(h_filter, def);
 456         }
 457
 458         /* rule container chains */
 459         fwd_r_new_chain(h_filter, "mssfix");
 460         fwd_r_new_chain(h_filter, "zones");
 461         fwd_r_new_chain(h_filter, "rules");
 462         fwd_r_new_chain(h_filter, "redirects");
 463         fwd_r_new_chain(h_filter, "forwardings");
 464         fwd_r_jump_chain(h_filter, "INPUT", "rules");
 465         fwd_r_jump_chain(h_filter, "FORWARD", "mssfix");
 466         fwd_r_jump_chain(h_filter, "FORWARD", "zones");
 467         fwd_r_jump_chain(h_filter, "FORWARD", "rules");
 468         fwd_r_jump_chain(h_filter, "FORWARD", "redirects");
 469         fwd_r_jump_chain(h_filter, "FORWARD", "forwardings");
 470         fwd_r_new_chain(h_nat, "zonemasq");
 471         fwd_r_new_chain(h_nat, "redirects");
 472         fwd_r_new_chain(h_nat, "loopback");
 473         fwd_r_jump_chain(h_nat, "POSTROUTING", "zonemasq");
 474         fwd_r_jump_chain(h_nat, "PREROUTING", "redirects");
 475         fwd_r_jump_chain(h_nat, "POSTROUTING", "loopback");
 476
 477         /* standard drop, accept, reject chain */
 478         fwd_r_handle_drop(h_filter);
 479         fwd_r_handle_accept(h_filter);
 480         fwd_r_handle_reject(h_filter);
 481
 482
 483         if( !iptc_commit(h_nat) )
 484                 fwd_fatal("Cannot commit nat table: %s", iptc_strerror(errno));
 485
 486         if( !iptc_commit(h_filter) )
 487                 fwd_fatal("Cannot commit filter table: %s", iptc_strerror(errno));
 488
 489         iptc_free(h_nat);
 490         iptc_free(h_filter);
 491 }
 492
 493
 494 void fwd_ipt_build_ruleset(struct fwd_handle *h)
 495 {
 496         struct fwd_data *e;
 497
 498         fwd_xt_init();
 499
 500         for( e = h->conf; e; e = e->next )
 501         {
 502                 switch(e->type)
 503                 {
 504                         case FWD_S_DEFAULTS:
 505                                 printf("\n## DEFAULTS\n");
 506                                 fwd_ipt_defaults_create(e);
 507                                 break;
 508
 509                         case FWD_S_INCLUDE:
 510                                 printf("\n## INCLUDE %s\n", e->section.include.path);
 511                                 break;
 512
 513                         case FWD_S_ZONE:
 514                         case FWD_S_FORWARD:
 515                         case FWD_S_REDIRECT:
 516                         case FWD_S_RULE:
 517                                 /* Make gcc happy */
 518                                 break;
 519                 }
 520         }
 521 }
 522
 523
 524 static struct fwd_zone *
 525 fwd_lookup_zone(struct fwd_handle *h, const char *net)
 526 {
 527         struct fwd_data *e;
 528         struct fwd_network_list *n;
 529
 530         for( e = h->conf; e; e = e->next )
 531                 if( e->type == FWD_S_ZONE )
 532                         for( n = e->section.zone.networks; n; n = n->next )
 533                                 if( !strcmp(n->name, net) )
 534                                         return &e->section.zone;
 535
 536         return NULL;
 537 }
 538
 539 static struct fwd_network_list *
 540 fwd_lookup_network(struct fwd_zone *z, const char *net)
 541 {
 542         struct fwd_network_list *n;
 543
 544         for( n = z->networks; n; n = n->next )
 545                 if( !strcmp(n->name, net) )
 546                         return n;
 547
 548         return NULL;
 549 }
 550
 551 static struct fwd_addr_list *
 552 fwd_lookup_addr(struct fwd_handle *h, struct fwd_network_list *n)
 553 {
 554         struct fwd_addr_list *a;
 555
 556         if( n != NULL )
 557                 for( a = h->addrs; a; a = a->next )
 558                         if( !strcmp(a->ifname, n->ifname) )
 559                                 return a;
 560
 561         return NULL;
 562 }
 563
 564 void fwd_ipt_addif(struct fwd_handle *h, const char *net)
 565 {
 566         struct fwd_data *e;
 567         struct fwd_zone *z;
 568         struct fwd_rule *c;
 569         struct fwd_redirect *r;
 570         struct fwd_forwarding *f;
 571         struct fwd_addr_list *a, *a2;
 572         struct fwd_network_list *n, *n2;
 573         struct fwd_proto p;
 574
 575         struct fwd_xt_rule *x;
 576         struct xtables_match *m;
 577         struct xtables_target *t;
 578
 579         struct iptc_handle *h_filter, *h_nat;
 580
 581         if( !(h_filter = iptc_init("filter")) || !(h_nat = iptc_init("nat")) )
 582                 fwd_fatal("Unable to obtain libiptc handle");
 583
 584
 585         if( !(z = fwd_lookup_zone(h, net)) )
 586                 return;
 587
 588         if( !(n = fwd_lookup_network(z, net)) )
 589                 return;
 590
 591         if( !(a = fwd_lookup_addr(h, n)) )
 592                 return;
 593
 594         printf("\n\n#\n# addif(%s)\n#\n", net);
 595
 596         /* Build masquerading rule */
 597         if( z->masq )
 598         {
 599                 printf("\n# Net %s (%s) - masq\n", n->name, n->ifname);
 600
 601                 if( (x = fwd_xt_init_rule(h_nat)) != NULL )
 602                 {
 603                         fwd_xt_parse_out(x, n, 0);                                      /* -o ... */
 604                         fwd_xt_get_target(x, "MASQUERADE");                     /* -j MASQUERADE */
 605                         fwd_r_add_comment(x, "masq", z, NULL, n);       /* -m comment ... */
 606                         fwd_xt_append_rule(x, "zonemasq");                      /* -A zonemasq */
 607                 }
 608         }
 609
 610         /* Build MSS fix rule */
 611         if( z->mtu_fix )
 612         {
 613                 printf("\n# Net %s (%s) - mtu_fix\n", n->name, n->ifname);
 614
 615                 if( (x = fwd_xt_init_rule(h_filter)) != NULL )
 616                 {
 617                         p.type = FWD_PR_TCP;
 618                         fwd_xt_parse_out(x, n, 0);                                      /* -o ... */
 619                         fwd_xt_parse_proto(x, &p, 0);                           /* -p tcp */
 620
 621                         /* -m tcp --tcp-flags SYN,RST SYN */
 622                         if( (m = fwd_xt_get_match(x, "tcp")) != NULL )
 623                                 fwd_xt_parse_match(x, m, "--tcp-flags", "SYN,RST", "SYN");
 624
 625                         /* -j TCPMSS --clamp-mss-to-pmtu */
 626                         if( (t = fwd_xt_get_target(x, "TCPMSS")) != NULL )
 627                                 fwd_xt_parse_target(x, t, "--clamp-mss-to-pmtu");
 628
 629                         /* -m comment ... */
 630                         fwd_r_add_comment(x, "mssfix", z, NULL, n);
 631
 632                         /* -A mssfix */
 633                         fwd_xt_append_rule(x, "mssfix");
 634                 }
 635         }
 636
 637         /* Build intra-zone forwarding rules */
 638         for( n2 = z->networks; n2; n2 = n2->next )
 639         {
 640                 if( (a2 = fwd_lookup_addr(h, n2)) != NULL )
 641                 {
 642                         printf("\n# Net %s (%s) - intra-zone-forwarding"
 643                                " Z:%s N:%s I:%s -> Z:%s N:%s I:%s\n",
 644                                 n->name, n->ifname, z->name, n->name, n->ifname,
 645                                 z->name, n2->name, n2->ifname);
 646
 647                         if( (x = fwd_xt_init_rule(h_filter)) != NULL )
 648                         {
 649                                 fwd_xt_parse_in(x, n, 0);                               /* -i ... */
 650                                 fwd_xt_parse_out(x, n2, 0);                             /* -o ... */
 651                                 fwd_r_add_policytarget(x, z->forward);  /* -j handle_... */
 652                                 fwd_r_add_comment(x, "zone", z, n, n2); /* -m comment ... */
 653                                 fwd_xt_append_rule(x, "zones");                 /* -A zones */
 654                         }
 655                 }
 656         }
 657
 658         /* Build inter-zone forwarding rules */
 659         for( e = z->forwardings; e && (f = &e->section.forwarding); e = e->next )
 660         {
 661                 for( n2 = f->dest->networks; n2; n2 = n2->next )
 662                 {
 663                         printf("\n# Net %s (%s) - inter-zone-forwarding"
 664                    " Z:%s N:%s I:%s -> Z:%s N:%s I:%s\n",
 665                                 n->name, n->ifname, z->name, n->name, n->ifname,
 666                                 f->dest->name, n2->name, n2->ifname);
 667
 668                         /* Build forwarding rule */
 669                         if( (x = fwd_xt_init_rule(h_filter)) != NULL )
 670                         {
 671                                 fwd_xt_parse_in(x, n, 0);                                       /* -i ... */
 672                                 fwd_xt_parse_out(x, n2, 0);                                     /* -o ... */
 673                                 fwd_r_add_policytarget(x, FWD_P_ACCEPT);        /* -j handle_... */
 674                                 fwd_r_add_comment(x, "forward", z, n, n2);      /* -m comment ... */
 675                                 fwd_xt_append_rule(x, "forwardings");                   /* -A forwardings */
 676                         }
 677                 }
 678         }
 679
 680         /* Build DNAT rules */
 681         for( e = z->redirects; e && (r = &e->section.redirect); e = e->next )
 682         {
 683                 printf("\n# Net %s (%s) - redirect Z:%s N:%s I:%s\n",
 684                         n->name, n->ifname, z->name, n->name, n->ifname);
 685
 686                 /* DNAT */
 687                 if( (x = fwd_xt_init_rule(h_nat)) != NULL )
 688                 {
 689                         fwd_xt_parse_in(x, n, 0);                                       /* -i ... */
 690                         fwd_xt_parse_src(x, r->src_ip, 0);                      /* -s ... */
 691                         fwd_xt_parse_dest(x, &a->ipaddr, 0);            /* -d ... */
 692                         fwd_xt_parse_proto(x, r->proto, 0);                     /* -p ... */
 693                         fwd_r_add_sport(x, r->src_port);                        /* --sport ... */
 694                         fwd_r_add_dport(x, r->src_dport);                       /* --dport ... */
 695                         fwd_r_add_srcmac(x, r->src_mac);                        /* -m mac --mac-source ... */
 696                         fwd_r_add_dnattarget(x, r->dest_ip, r->dest_port);      /* -j DNAT ... */
 697                         fwd_r_add_comment(x, "redir", z, n, NULL);      /* -m comment ... */
 698                         fwd_xt_append_rule(x, "redirects");                     /* -A redirects */
 699                 }
 700
 701                 /* Forward */
 702                 if( (x = fwd_xt_init_rule(h_filter)) != NULL )
 703                 {
 704                         fwd_xt_parse_in(x, n, 0);                                       /* -i ... */
 705                         fwd_xt_parse_src(x, r->src_ip, 0);                      /* -s ... */
 706                         fwd_xt_parse_dest(x, r->dest_ip, 0);            /* -d ... */
 707                         fwd_xt_parse_proto(x, r->proto, 0);                     /* -p ... */
 708                         fwd_r_add_srcmac(x, r->src_mac);                        /* -m mac --mac-source ... */
 709                         fwd_r_add_sport(x, r->src_port);                        /* --sport ... */
 710                         fwd_r_add_dport(x, r->dest_port);                       /* --dport ... */
 711                         fwd_r_add_policytarget(x, FWD_P_ACCEPT);        /* -j handle_accept */
 712                         fwd_r_add_comment(x, "redir", z, n, NULL);      /* -m comment ... */
 713                         fwd_xt_append_rule(x, "redirects");                     /* -A redirects */
 714                 }
 715
 716                 /* Add loopback rule if neither src_ip nor src_mac are defined */
 717                 if( !r->src_ip && !r->src_mac )
 718                 {
 719                         if( (x = fwd_xt_init_rule(h_nat)) != NULL )
 720                         {
 721                                 fwd_xt_parse_in(x, n, 1);                                       /* -i ! ... */
 722                                 fwd_xt_parse_dest(x, r->dest_ip, 0);            /* -d ... */
 723                                 fwd_xt_parse_proto(x, r->proto, 0);                     /* -p ... */
 724                                 fwd_r_add_sport(x, r->src_port);                        /* --sport ... */
 725                                 fwd_r_add_dport(x, r->src_dport);                       /* --dport ... */
 726                                 fwd_xt_get_target(x, "MASQUERADE");                     /* -j MASQUERADE */
 727                                 fwd_r_add_comment(x, "redir", z, n, NULL);      /* -m comment ... */
 728                                 fwd_xt_append_rule(x, "loopback");                      /* -A loopback */
 729                         }
 730                 }
 731         }
 732
 733         /* Build rules */
 734         for( e = z->rules; e && (c = &e->section.rule); e = e->next )
 735         {
 736                 /* Has destination, add forward rule for each network in target zone */
 737                 if( c->dest )
 738                 {
 739                         for( n2 = c->dest->networks; n2; n2 = n2->next )
 740                         {
 741                                 printf("\n# Net %s (%s) - rule+dest"
 742                                " Z:%s N:%s I:%s -> Z:%s N:%s I:%s\n",
 743                                         n->name, n->ifname, z->name, n->name, n->ifname,
 744                                         f->dest->name, n2->name, n2->ifname);
 745
 746                                 if( (x = fwd_xt_init_rule(h_filter)) != NULL )
 747                                 {
 748                                         fwd_xt_parse_in(x, n, 0);                               /* -i ... */
 749                                         fwd_xt_parse_out(x, n2, 0);                             /* -o ... */
 750                                         fwd_xt_parse_src(x, c->src_ip, 0);              /* -s ... */
 751                                         fwd_xt_parse_dest(x, c->dest_ip, 0);    /* -d ... */
 752                                         fwd_xt_parse_proto(x, c->proto, 0);             /* -p ... */
 753                                         fwd_r_add_icmptype(x, c->icmp_type);    /* --icmp-type ... */
 754                                         fwd_r_add_srcmac(x, c->src_mac);                /* --mac-source ... */
 755                                         fwd_r_add_sport(x, c->src_port);                /* --sport ... */
 756                                         fwd_r_add_dport(x, c->dest_port);               /* --dport ... */
 757                                         fwd_r_add_policytarget(x, c->target);   /* -j handle_... */
 758                                         fwd_r_add_comment(x, "rule", z, n, n2); /* -m comment ... */
 759                                         fwd_xt_append_rule(x, "rules");                 /* -A rules */
 760                                 }
 761                         }
 762                 }
 763
 764                 /* No destination specified, treat it as input rule */
 765                 else
 766                 {
 767                         printf("\n# Net %s (%s) - rule Z:%s N:%s I:%s\n",
 768                                 n->name, n->ifname, z->name, n->name, n->ifname);
 769
 770                         if( (x = fwd_xt_init_rule(h_filter)) != NULL )
 771                         {
 772                                 fwd_xt_parse_in(x, n, 0);                                       /* -i ... */
 773                                 fwd_xt_parse_src(x, c->src_ip, 0);                      /* -s ... */
 774                                 fwd_xt_parse_dest(x, c->dest_ip, 0);            /* -d ... */
 775                                 fwd_xt_parse_proto(x, c->proto, 0);                     /* -p ... */
 776                                 fwd_r_add_icmptype(x, c->icmp_type);            /* --icmp-type ... */
 777                                 fwd_r_add_srcmac(x, c->src_mac);                        /* --mac-source ... */
 778                                 fwd_r_add_sport(x, c->src_port);                        /* --sport ... */
 779                                 fwd_r_add_dport(x, c->dest_port);                       /* --dport ... */
 780                                 fwd_r_add_policytarget(x, c->target);           /* -j handle_... */
 781                                 fwd_r_add_comment(x, "rule", z, n, NULL);       /* -m comment ... */
 782                                 fwd_xt_append_rule(x, "rules");                         /* -A rules */
 783                         }
 784                 }
 785         }
 786
 787         if( !iptc_commit(h_nat) )
 788                 fwd_fatal("Cannot commit nat table: %s", iptc_strerror(errno));
 789
 790         if( !iptc_commit(h_filter) )
 791                 fwd_fatal("Cannot commit filter table: %s", iptc_strerror(errno));
 792
 793         iptc_free(h_nat);
 794         iptc_free(h_filter);
 795 }
 796
 797
 798 static void fwd_ipt_delif_table(struct iptc_handle *h, const char *net)
 799 {
 800         struct xt_entry_match *m;
 801         struct ipt_entry *e;
 802         const char *chain, *comment;
 803         size_t off = 0, num = 0;
 804
 805         /* iterate chains */
 806         for( chain = iptc_first_chain(h); chain;
 807              chain = iptc_next_chain(h)
 808         ) {
 809                 /* iterate rules */
 810                 for( e = iptc_first_rule(chain, h), num = 0; e;
 811                      e = iptc_next_rule(e, h), num++
 812                 ) {
 813                         repeat_rule:
 814
 815                         /* skip entries w/o matches */
 816                         if( ! e->target_offset )
 817                                 continue;
 818
 819                         /* iterate matches */
 820                         for( off = sizeof(struct ipt_entry);
 821                              off < e->target_offset;
 822                              off += m->u.match_size
 823                         ) {
 824                                 m = (void *)e + off;
 825
 826                                 /* yay */
 827                                 if( ! strcmp(m->u.user.name, "comment") )
 828                                 {
 829                                         /* better use struct_xt_comment_info but well... */
 830                                         comment = (void *)m + sizeof(struct xt_entry_match);
 831
 832                                         if( fwd_r_cmp("src:", comment, net) )
 833                                         {
 834                                                 e = iptc_next_rule(e, h);
 835                                                 iptc_delete_num_entry(chain, num, h);
 836
 837                                                 if( e != NULL )
 838                                                         goto repeat_rule;
 839                                                 else
 840                                                         break;
 841                                         }
 842                                 }
 843                         }
 844                 }
 845         }
 846 }
 847
 848 void fwd_ipt_delif(struct fwd_handle *h, const char *net)
 849 {
 850         struct iptc_handle *h_filter, *h_nat;
 851
 852         if( !(h_filter = iptc_init("filter")) || !(h_nat = iptc_init("nat")) )
 853                 fwd_fatal("Unable to obtain libiptc handle");
 854
 855
 856         printf("\n\n#\n# delif(%s)\n#\n", net);
 857
 858         /* delete network related rules */
 859         fwd_ipt_delif_table(h_nat, net);
 860         fwd_ipt_delif_table(h_filter, net);
 861
 862
 863         if( !iptc_commit(h_nat) )
 864                 fwd_fatal("Cannot commit nat table: %s", iptc_strerror(errno));
 865
 866         if( !iptc_commit(h_filter) )
 867                 fwd_fatal("Cannot commit filter table: %s", iptc_strerror(errno));
 868
 869         iptc_free(h_nat);
 870         iptc_free(h_filter);
 871 }
 872
 873
 874 static void fwd_ipt_clear_ruleset_table(struct iptc_handle *h)
 875 {
 876         const char *chain;
 877
 878         /* pass 1: flush all chains */
 879         for( chain = iptc_first_chain(h); chain;
 880              chain = iptc_next_chain(h)
 881         ) {
 882                 iptc_flush_entries(chain, h);
 883         }
 884
 885         /* pass 2: remove user defined chains */
 886         for( chain = iptc_first_chain(h); chain;
 887              chain = iptc_next_chain(h)
 888         ) {
 889                 if( ! iptc_builtin(chain, h) )
 890                         iptc_delete_chain(chain, h);
 891         }
 892 }
 893
 894 void fwd_ipt_clear_ruleset(struct fwd_handle *h)
 895 {
 896         struct iptc_handle *h_filter, *h_nat;
 897
 898         if( !(h_filter = iptc_init("filter")) || !(h_nat = iptc_init("nat")) )
 899                 fwd_fatal("Unable to obtain libiptc handle");
 900
 901         /* flush tables */
 902         fwd_ipt_clear_ruleset_table(h_nat);
 903         fwd_ipt_clear_ruleset_table(h_filter);
 904
 905         /* revert policies */
 906         fwd_r_set_policy(h_filter, "INPUT", "ACCEPT");
 907         fwd_r_set_policy(h_filter, "OUTPUT", "ACCEPT");
 908         fwd_r_set_policy(h_filter, "FORWARD", "ACCEPT");
 909
 910
 911         if( !iptc_commit(h_nat) )
 912                 fwd_fatal("Cannot commit nat table: %s", iptc_strerror(errno));
 913
 914         if( !iptc_commit(h_filter) )
 915                 fwd_fatal("Cannot commit filter table: %s", iptc_strerror(errno));
 916
 917         iptc_free(h_nat);
 918         iptc_free(h_filter);
 919 }
 920