www.tinc-vpn.org Git - tinc/blob - src/subnet.c

   1 /*
   2     subnet.c -- handle subnet lookups and lists
   3     Copyright (C) 2000-2019 Guus Sliepen <guus@tinc-vpn.org>,
   4                   2000-2005 Ivo Timmermans
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License along
  17     with this program; if not, write to the Free Software Foundation, Inc.,
  18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include "system.h"
  22
  23 #include "avl_tree.h"
  24 #include "device.h"
  25 #include "logger.h"
  26 #include "net.h"
  27 #include "netutl.h"
  28 #include "node.h"
  29 #include "process.h"
  30 #include "subnet.h"
  31 #include "utils.h"
  32 #include "xalloc.h"
  33
  34 /* lists type of subnet */
  35
  36 avl_tree_t *subnet_tree;
  37
  38 /* Subnet lookup cache */
  39
  40 static ipv4_t cache_ipv4_address[2];
  41 static subnet_t *cache_ipv4_subnet[2];
  42 static bool cache_ipv4_valid[2];
  43 static int cache_ipv4_slot;
  44
  45 static ipv6_t cache_ipv6_address[2];
  46 static subnet_t *cache_ipv6_subnet[2];
  47 static bool cache_ipv6_valid[2];
  48 static int cache_ipv6_slot;
  49
  50 static mac_t cache_mac_address[2];
  51 static subnet_t *cache_mac_subnet[2];
  52 static bool cache_mac_valid[2];
  53 static int cache_mac_slot;
  54
  55 void subnet_cache_flush(void) {
  56         cache_ipv4_valid[0] = cache_ipv4_valid[1] = false;
  57         cache_ipv6_valid[0] = cache_ipv6_valid[1] = false;
  58         cache_mac_valid[0] = cache_mac_valid[1] = false;
  59 }
  60
  61 /* Subnet comparison */
  62
  63 static int subnet_compare_mac(const subnet_t *a, const subnet_t *b) {
  64         int result;
  65
  66         result = memcmp(&a->net.mac.address, &b->net.mac.address, sizeof(mac_t));
  67
  68         if(result) {
  69                 return result;
  70         }
  71
  72         result = a->weight - b->weight;
  73
  74         if(result || !a->owner || !b->owner) {
  75                 return result;
  76         }
  77
  78         return strcmp(a->owner->name, b->owner->name);
  79 }
  80
  81 static int subnet_compare_ipv4(const subnet_t *a, const subnet_t *b) {
  82         int result;
  83
  84         result = b->net.ipv4.prefixlength - a->net.ipv4.prefixlength;
  85
  86         if(result) {
  87                 return result;
  88         }
  89
  90         result = memcmp(&a->net.ipv4.address, &b->net.ipv4.address, sizeof(ipv4_t));
  91
  92         if(result) {
  93                 return result;
  94         }
  95
  96         result = a->weight - b->weight;
  97
  98         if(result || !a->owner || !b->owner) {
  99                 return result;
 100         }
 101
 102         return strcmp(a->owner->name, b->owner->name);
 103 }
 104
 105 static int subnet_compare_ipv6(const subnet_t *a, const subnet_t *b) {
 106         int result;
 107
 108         result = b->net.ipv6.prefixlength - a->net.ipv6.prefixlength;
 109
 110         if(result) {
 111                 return result;
 112         }
 113
 114         result = memcmp(&a->net.ipv6.address, &b->net.ipv6.address, sizeof(ipv6_t));
 115
 116         if(result) {
 117                 return result;
 118         }
 119
 120         result = a->weight - b->weight;
 121
 122         if(result || !a->owner || !b->owner) {
 123                 return result;
 124         }
 125
 126         return strcmp(a->owner->name, b->owner->name);
 127 }
 128
 129 int subnet_compare(const subnet_t *a, const subnet_t *b) {
 130         int result;
 131
 132         result = a->type - b->type;
 133
 134         if(result) {
 135                 return result;
 136         }
 137
 138         switch(a->type) {
 139         case SUBNET_MAC:
 140                 return subnet_compare_mac(a, b);
 141
 142         case SUBNET_IPV4:
 143                 return subnet_compare_ipv4(a, b);
 144
 145         case SUBNET_IPV6:
 146                 return subnet_compare_ipv6(a, b);
 147
 148         default:
 149                 logger(LOG_ERR, "subnet_compare() was called with unknown subnet type %d, exitting!",
 150                        a->type);
 151                 exit(0);
 152         }
 153
 154         return 0;
 155 }
 156
 157 /* Initialising trees */
 158
 159 void init_subnets(void) {
 160         subnet_tree = avl_alloc_tree((avl_compare_t) subnet_compare, (avl_action_t) free_subnet);
 161
 162         subnet_cache_flush();
 163 }
 164
 165 void exit_subnets(void) {
 166         avl_delete_tree(subnet_tree);
 167 }
 168
 169 avl_tree_t *new_subnet_tree(void) {
 170         return avl_alloc_tree((avl_compare_t) subnet_compare, NULL);
 171 }
 172
 173 void free_subnet_tree(avl_tree_t *subnet_tree) {
 174         avl_delete_tree(subnet_tree);
 175 }
 176
 177 /* Allocating and freeing space for subnets */
 178
 179 subnet_t *new_subnet(void) {
 180         return xmalloc_and_zero(sizeof(subnet_t));
 181 }
 182
 183 void free_subnet(subnet_t *subnet) {
 184         free(subnet);
 185 }
 186
 187 /* Adding and removing subnets */
 188
 189 void subnet_add(node_t *n, subnet_t *subnet) {
 190         subnet->owner = n;
 191
 192         avl_insert(subnet_tree, subnet);
 193         avl_insert(n->subnet_tree, subnet);
 194
 195         subnet_cache_flush();
 196 }
 197
 198 void subnet_del(node_t *n, subnet_t *subnet) {
 199         avl_delete(n->subnet_tree, subnet);
 200         avl_delete(subnet_tree, subnet);
 201
 202         subnet_cache_flush();
 203 }
 204
 205 /* Ascii representation of subnets */
 206
 207 bool str2net(subnet_t *subnet, const char *subnetstr) {
 208         char str[1024];
 209         strncpy(str, subnetstr, sizeof(str));
 210         str[sizeof(str) - 1] = 0;
 211         int consumed;
 212
 213         int weight = 10;
 214         char *weight_separator = strchr(str, '#');
 215
 216         if(weight_separator) {
 217                 char *weight_str = weight_separator + 1;
 218
 219                 if(sscanf(weight_str, "%d%n", &weight, &consumed) < 1) {
 220                         return false;
 221                 }
 222
 223                 if(weight_str[consumed]) {
 224                         return false;
 225                 }
 226
 227                 *weight_separator = 0;
 228         }
 229
 230         int prefixlength = -1;
 231         char *prefixlength_separator = strchr(str, '/');
 232
 233         if(prefixlength_separator) {
 234                 char *prefixlength_str = prefixlength_separator + 1;
 235
 236                 if(sscanf(prefixlength_str, "%d%n", &prefixlength, &consumed) < 1) {
 237                         return false;
 238                 }
 239
 240                 if(prefixlength_str[consumed]) {
 241                         return false;
 242                 }
 243
 244                 *prefixlength_separator = 0;
 245
 246                 if(prefixlength < 0) {
 247                         return false;
 248                 }
 249         }
 250
 251         uint16_t x[8];
 252
 253         if(sscanf(str, "%hx:%hx:%hx:%hx:%hx:%hx%n", &x[0], &x[1], &x[2], &x[3], &x[4], &x[5], &consumed) >= 6 && !str[consumed]) {
 254                 /*
 255                    Normally we should check that each part has two digits to prevent ambiguities.
 256                    However, in old tinc versions net2str() will aggressively return MAC addresses with one-digit parts,
 257                    so we have to accept them otherwise we would be unable to parse ADD_SUBNET messages.
 258                 */
 259                 if(prefixlength >= 0) {
 260                         return false;
 261                 }
 262
 263                 subnet->type = SUBNET_MAC;
 264                 subnet->weight = weight;
 265
 266                 for(int i = 0; i < 6; i++) {
 267                         subnet->net.mac.address.x[i] = x[i];
 268                 }
 269
 270                 return true;
 271         }
 272
 273         if(sscanf(str, "%hu.%hu.%hu.%hu%n", &x[0], &x[1], &x[2], &x[3], &consumed) >= 4 && !str[consumed]) {
 274                 if(prefixlength == -1) {
 275                         prefixlength = 32;
 276                 }
 277
 278                 if(prefixlength > 32) {
 279                         return false;
 280                 }
 281
 282                 subnet->type = SUBNET_IPV4;
 283                 subnet->net.ipv4.prefixlength = prefixlength;
 284                 subnet->weight = weight;
 285
 286                 for(int i = 0; i < 4; i++) {
 287                         if(x[i] > 255) {
 288                                 return false;
 289                         }
 290
 291                         subnet->net.ipv4.address.x[i] = x[i];
 292                 }
 293
 294                 return true;
 295         }
 296
 297         /* IPv6 */
 298
 299         char *last_colon = strrchr(str, ':');
 300
 301         if(last_colon && sscanf(last_colon, ":%hu.%hu.%hu.%hu%n", &x[0], &x[1], &x[2], &x[3], &consumed) >= 4 && !last_colon[consumed]) {
 302                 /* Dotted quad suffix notation, convert to standard IPv6 notation */
 303                 for(int i = 0; i < 4; i++)
 304                         if(x[i] > 255) {
 305                                 return false;
 306                         }
 307
 308                 snprintf(last_colon, sizeof(str) - (last_colon - str), ":%02x%02x:%02x%02x", x[0], x[1], x[2], x[3]);
 309         }
 310
 311         char *double_colon = strstr(str, "::");
 312
 313         if(double_colon) {
 314                 /* Figure out how many zero groups we need to expand */
 315                 int zero_group_count = 8;
 316
 317                 for(const char *cur = str; *cur; cur++)
 318                         if(*cur != ':') {
 319                                 zero_group_count--;
 320
 321                                 while(cur[1] && cur[1] != ':') {
 322                                         cur++;
 323                                 }
 324                         }
 325
 326                 if(zero_group_count < 1) {
 327                         return false;
 328                 }
 329
 330                 /* Split the double colon in the middle to make room for zero groups */
 331                 double_colon++;
 332                 memmove(double_colon + (zero_group_count * 2 - 1), double_colon, strlen(double_colon) + 1);
 333
 334                 /* Write zero groups in the resulting gap, overwriting the second colon */
 335                 for(int i = 0; i < zero_group_count; i++) {
 336                         memcpy(&double_colon[i * 2], "0:", 2);
 337                 }
 338
 339                 /* Remove any leading or trailing colons */
 340                 if(str[0] == ':') {
 341                         memmove(&str[0], &str[1], strlen(&str[1]) + 1);
 342                 }
 343
 344                 if(str[strlen(str) - 1] == ':') {
 345                         str[strlen(str) - 1] = 0;
 346                 }
 347         }
 348
 349         if(sscanf(str, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx%n",
 350                         &x[0], &x[1], &x[2], &x[3], &x[4], &x[5], &x[6], &x[7], &consumed) >= 8 && !str[consumed]) {
 351                 if(prefixlength == -1) {
 352                         prefixlength = 128;
 353                 }
 354
 355                 if(prefixlength > 128) {
 356                         return false;
 357                 }
 358
 359                 subnet->type = SUBNET_IPV6;
 360                 subnet->net.ipv6.prefixlength = prefixlength;
 361                 subnet->weight = weight;
 362
 363                 for(int i = 0; i < 8; i++) {
 364                         subnet->net.ipv6.address.x[i] = htons(x[i]);
 365                 }
 366
 367                 return true;
 368         }
 369
 370         return false;
 371 }
 372
 373 bool net2str(char *netstr, int len, const subnet_t *subnet) {
 374         if(!netstr || !subnet) {
 375                 logger(LOG_ERR, "net2str() was called with netstr=%p, subnet=%p!", (void *)netstr, (void *)subnet);
 376                 return false;
 377         }
 378
 379         switch(subnet->type) {
 380         case SUBNET_MAC:
 381                 snprintf(netstr, len, "%x:%x:%x:%x:%x:%x#%d",
 382                          subnet->net.mac.address.x[0],
 383                          subnet->net.mac.address.x[1],
 384                          subnet->net.mac.address.x[2],
 385                          subnet->net.mac.address.x[3],
 386                          subnet->net.mac.address.x[4],
 387                          subnet->net.mac.address.x[5],
 388                          subnet->weight);
 389                 break;
 390
 391         case SUBNET_IPV4:
 392                 snprintf(netstr, len, "%u.%u.%u.%u/%d#%d",
 393                          subnet->net.ipv4.address.x[0],
 394                          subnet->net.ipv4.address.x[1],
 395                          subnet->net.ipv4.address.x[2],
 396                          subnet->net.ipv4.address.x[3],
 397                          subnet->net.ipv4.prefixlength,
 398                          subnet->weight);
 399                 break;
 400
 401         case SUBNET_IPV6:
 402                 snprintf(netstr, len, "%x:%x:%x:%x:%x:%x:%x:%x/%d#%d",
 403                          ntohs(subnet->net.ipv6.address.x[0]),
 404                          ntohs(subnet->net.ipv6.address.x[1]),
 405                          ntohs(subnet->net.ipv6.address.x[2]),
 406                          ntohs(subnet->net.ipv6.address.x[3]),
 407                          ntohs(subnet->net.ipv6.address.x[4]),
 408                          ntohs(subnet->net.ipv6.address.x[5]),
 409                          ntohs(subnet->net.ipv6.address.x[6]),
 410                          ntohs(subnet->net.ipv6.address.x[7]),
 411                          subnet->net.ipv6.prefixlength,
 412                          subnet->weight);
 413                 break;
 414
 415         default:
 416                 logger(LOG_ERR,
 417                        "net2str() was called with unknown subnet type %d, exiting!",
 418                        subnet->type);
 419                 exit(0);
 420         }
 421
 422         return true;
 423 }
 424
 425 /* Subnet lookup routines */
 426
 427 subnet_t *lookup_subnet(const node_t *owner, const subnet_t *subnet) {
 428         return avl_search(owner->subnet_tree, subnet);
 429 }
 430
 431 subnet_t *lookup_subnet_mac(const node_t *owner, const mac_t *address) {
 432         subnet_t *p, *r = NULL;
 433         avl_node_t *n;
 434         int i;
 435
 436         // Check if this address is cached
 437
 438         for(i = 0; i < 2; i++) {
 439                 if(!cache_mac_valid[i]) {
 440                         continue;
 441                 }
 442
 443                 if(owner && cache_mac_subnet[i] && cache_mac_subnet[i]->owner != owner) {
 444                         continue;
 445                 }
 446
 447                 if(!memcmp(address, &cache_mac_address[i], sizeof(*address))) {
 448                         return cache_mac_subnet[i];
 449                 }
 450         }
 451
 452         // Search all subnets for a matching one
 453
 454         for(n = owner ? owner->subnet_tree->head : subnet_tree->head; n; n = n->next) {
 455                 p = n->data;
 456
 457                 if(!p || p->type != SUBNET_MAC) {
 458                         continue;
 459                 }
 460
 461                 if(!memcmp(address, &p->net.mac.address, sizeof(*address))) {
 462                         r = p;
 463
 464                         if(p->owner->status.reachable) {
 465                                 break;
 466                         }
 467                 }
 468         }
 469
 470         // Cache the result
 471
 472         cache_mac_slot = !cache_mac_slot;
 473         memcpy(&cache_mac_address[cache_mac_slot], address, sizeof(*address));
 474         cache_mac_subnet[cache_mac_slot] = r;
 475         cache_mac_valid[cache_mac_slot] = true;
 476
 477         return r;
 478 }
 479
 480 subnet_t *lookup_subnet_ipv4(const ipv4_t *address) {
 481         subnet_t *p, *r = NULL;
 482         avl_node_t *n;
 483         int i;
 484
 485         // Check if this address is cached
 486
 487         for(i = 0; i < 2; i++) {
 488                 if(!cache_ipv4_valid[i]) {
 489                         continue;
 490                 }
 491
 492                 if(!memcmp(address, &cache_ipv4_address[i], sizeof(*address))) {
 493                         return cache_ipv4_subnet[i];
 494                 }
 495         }
 496
 497         // Search all subnets for a matching one
 498
 499         for(n = subnet_tree->head; n; n = n->next) {
 500                 p = n->data;
 501
 502                 if(!p || p->type != SUBNET_IPV4) {
 503                         continue;
 504                 }
 505
 506                 if(!maskcmp(address, &p->net.ipv4.address, p->net.ipv4.prefixlength)) {
 507                         r = p;
 508
 509                         if(p->owner->status.reachable) {
 510                                 break;
 511                         }
 512                 }
 513         }
 514
 515         // Cache the result
 516
 517         cache_ipv4_slot = !cache_ipv4_slot;
 518         memcpy(&cache_ipv4_address[cache_ipv4_slot], address, sizeof(*address));
 519         cache_ipv4_subnet[cache_ipv4_slot] = r;
 520         cache_ipv4_valid[cache_ipv4_slot] = true;
 521
 522         return r;
 523 }
 524
 525 subnet_t *lookup_subnet_ipv6(const ipv6_t *address) {
 526         subnet_t *p, *r = NULL;
 527         avl_node_t *n;
 528         int i;
 529
 530         // Check if this address is cached
 531
 532         for(i = 0; i < 2; i++) {
 533                 if(!cache_ipv6_valid[i]) {
 534                         continue;
 535                 }
 536
 537                 if(!memcmp(address, &cache_ipv6_address[i], sizeof(*address))) {
 538                         return cache_ipv6_subnet[i];
 539                 }
 540         }
 541
 542         // Search all subnets for a matching one
 543
 544         for(n = subnet_tree->head; n; n = n->next) {
 545                 p = n->data;
 546
 547                 if(!p || p->type != SUBNET_IPV6) {
 548                         continue;
 549                 }
 550
 551                 if(!maskcmp(address, &p->net.ipv6.address, p->net.ipv6.prefixlength)) {
 552                         r = p;
 553
 554                         if(p->owner->status.reachable) {
 555                                 break;
 556                         }
 557                 }
 558         }
 559
 560         // Cache the result
 561
 562         cache_ipv6_slot = !cache_ipv6_slot;
 563         memcpy(&cache_ipv6_address[cache_ipv6_slot], address, sizeof(*address));
 564         cache_ipv6_subnet[cache_ipv6_slot] = r;
 565         cache_ipv6_valid[cache_ipv6_slot] = true;
 566
 567         return r;
 568 }
 569
 570 void subnet_update(node_t *owner, subnet_t *subnet, bool up) {
 571         avl_node_t *node;
 572         int i;
 573         char *envp[10] = {NULL};
 574         char netstr[MAXNETSTR];
 575         char *name, *address, *port;
 576         char empty[] = "";
 577
 578         // Prepare environment variables to be passed to the script
 579
 580         xasprintf(&envp[0], "NETNAME=%s", netname ? netname : "");
 581         xasprintf(&envp[1], "DEVICE=%s", device ? device : "");
 582         xasprintf(&envp[2], "INTERFACE=%s", iface ? iface : "");
 583         xasprintf(&envp[3], "NODE=%s", owner->name);
 584         xasprintf(&envp[4], "NAME=%s", myself->name);
 585
 586         if(owner != myself) {
 587                 sockaddr2str(&owner->address, &address, &port);
 588                 // 5 and 6 are reserved for SUBNET and WEIGHT
 589                 xasprintf(&envp[7], "REMOTEADDRESS=%s", address);
 590                 xasprintf(&envp[8], "REMOTEPORT=%s", port);
 591                 free(port);
 592                 free(address);
 593         }
 594
 595         name = up ? "subnet-up" : "subnet-down";
 596
 597         if(!subnet) {
 598                 for(node = owner->subnet_tree->head; node; node = node->next) {
 599                         subnet = node->data;
 600
 601                         if(!net2str(netstr, sizeof(netstr), subnet)) {
 602                                 continue;
 603                         }
 604
 605                         // Strip the weight from the subnet, and put it in its own environment variable
 606                         char *weight = strchr(netstr, '#');
 607
 608                         if(weight) {
 609                                 *weight++ = 0;
 610                         } else {
 611                                 weight = empty;
 612                         }
 613
 614                         // Prepare the SUBNET and WEIGHT variables
 615                         free(envp[5]);
 616                         free(envp[6]);
 617
 618                         xasprintf(&envp[5], "SUBNET=%s", netstr);
 619                         xasprintf(&envp[6], "WEIGHT=%s", weight);
 620
 621                         execute_script(name, envp);
 622                 }
 623         } else {
 624                 if(net2str(netstr, sizeof(netstr), subnet)) {
 625                         // Strip the weight from the subnet, and put it in its own environment variable
 626                         char *weight = strchr(netstr, '#');
 627
 628                         if(weight) {
 629                                 *weight++ = 0;
 630                         } else {
 631                                 weight = empty;
 632                         }
 633
 634                         // Prepare the SUBNET and WEIGHT variables
 635                         xasprintf(&envp[5], "SUBNET=%s", netstr);
 636                         xasprintf(&envp[6], "WEIGHT=%s", weight);
 637
 638                         execute_script(name, envp);
 639                 }
 640         }
 641
 642         for(i = 0; i < 9; i++) {
 643                 free(envp[i]);
 644         }
 645 }
 646
 647 void dump_subnets(void) {
 648         char netstr[MAXNETSTR];
 649         subnet_t *subnet;
 650         avl_node_t *node;
 651
 652         logger(LOG_DEBUG, "Subnet list:");
 653
 654         for(node = subnet_tree->head; node; node = node->next) {
 655                 subnet = node->data;
 656
 657                 if(!net2str(netstr, sizeof(netstr), subnet)) {
 658                         continue;
 659                 }
 660
 661                 logger(LOG_DEBUG, " %s owner %s", netstr, subnet->owner->name);
 662         }
 663
 664         logger(LOG_DEBUG, "End of subnet list.");
 665 }