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[64];
 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(inet_pton(AF_INET, str, &subnet->net.ipv4.address)) {
 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                 return true;
 287         }
 288
 289         if(inet_pton(AF_INET6, str, &subnet->net.ipv6.address)) {
 290                 if(prefixlength == -1) {
 291                         prefixlength = 128;
 292                 }
 293
 294                 if(prefixlength > 128) {
 295                         return false;
 296                 }
 297
 298                 subnet->type = SUBNET_IPV6;
 299                 subnet->net.ipv6.prefixlength = prefixlength;
 300                 subnet->weight = weight;
 301
 302                 return true;
 303         }
 304
 305         return false;
 306 }
 307
 308 bool net2str(char *netstr, int len, const subnet_t *subnet) {
 309         if(!netstr || !subnet) {
 310                 logger(LOG_ERR, "net2str() was called with netstr=%p, subnet=%p!", (void *)netstr, (void *)subnet);
 311                 return false;
 312         }
 313
 314         int result;
 315         int prefixlength = -1;
 316
 317         switch(subnet->type) {
 318         case SUBNET_MAC:
 319                 snprintf(netstr, len, "%02x:%02x:%02x:%02x:%02x:%02x",
 320                          subnet->net.mac.address.x[0],
 321                          subnet->net.mac.address.x[1],
 322                          subnet->net.mac.address.x[2],
 323                          subnet->net.mac.address.x[3],
 324                          subnet->net.mac.address.x[4],
 325                          subnet->net.mac.address.x[5]);
 326                 break;
 327
 328         case SUBNET_IPV4:
 329                 inet_ntop(AF_INET, &subnet->net.ipv4.address, netstr, len);
 330                 prefixlength = subnet->net.ipv4.prefixlength;
 331
 332                 if(prefixlength == 32) {
 333                         prefixlength = -1;
 334                 }
 335
 336                 break;
 337
 338         case SUBNET_IPV6: {
 339                 inet_ntop(AF_INET6, &subnet->net.ipv6.address, netstr, len);
 340                 prefixlength = subnet->net.ipv6.prefixlength;
 341
 342                 if(prefixlength == 128) {
 343                         prefixlength = -1;
 344                 }
 345
 346                 break;
 347         }
 348
 349         default:
 350                 logger(LOG_ERR, "net2str() was called with unknown subnet type %d, exiting!", subnet->type);
 351                 exit(1);
 352         }
 353
 354         size_t used = strlen(netstr);
 355         netstr += used;
 356         len -= used;
 357
 358         if(prefixlength >= 0) {
 359                 result = snprintf(netstr, len, "/%d", prefixlength);
 360                 netstr += result;
 361                 len -= result;
 362         }
 363
 364         if(subnet->weight != 10) {
 365                 snprintf(netstr, len, "#%d", subnet->weight);
 366         }
 367
 368         return true;
 369 }
 370
 371 /* Subnet lookup routines */
 372
 373 subnet_t *lookup_subnet(const node_t *owner, const subnet_t *subnet) {
 374         return avl_search(owner->subnet_tree, subnet);
 375 }
 376
 377 subnet_t *lookup_subnet_mac(const node_t *owner, const mac_t *address) {
 378         subnet_t *p, *r = NULL;
 379         avl_node_t *n;
 380         int i;
 381
 382         // Check if this address is cached
 383
 384         for(i = 0; i < 2; i++) {
 385                 if(!cache_mac_valid[i]) {
 386                         continue;
 387                 }
 388
 389                 if(owner && cache_mac_subnet[i] && cache_mac_subnet[i]->owner != owner) {
 390                         continue;
 391                 }
 392
 393                 if(!memcmp(address, &cache_mac_address[i], sizeof(*address))) {
 394                         return cache_mac_subnet[i];
 395                 }
 396         }
 397
 398         // Search all subnets for a matching one
 399
 400         for(n = owner ? owner->subnet_tree->head : subnet_tree->head; n; n = n->next) {
 401                 p = n->data;
 402
 403                 if(!p || p->type != SUBNET_MAC) {
 404                         continue;
 405                 }
 406
 407                 if(!memcmp(address, &p->net.mac.address, sizeof(*address))) {
 408                         r = p;
 409
 410                         if(p->owner->status.reachable) {
 411                                 break;
 412                         }
 413                 }
 414         }
 415
 416         // Cache the result
 417
 418         cache_mac_slot = !cache_mac_slot;
 419         memcpy(&cache_mac_address[cache_mac_slot], address, sizeof(*address));
 420         cache_mac_subnet[cache_mac_slot] = r;
 421         cache_mac_valid[cache_mac_slot] = true;
 422
 423         return r;
 424 }
 425
 426 subnet_t *lookup_subnet_ipv4(const ipv4_t *address) {
 427         subnet_t *p, *r = NULL;
 428         avl_node_t *n;
 429         int i;
 430
 431         // Check if this address is cached
 432
 433         for(i = 0; i < 2; i++) {
 434                 if(!cache_ipv4_valid[i]) {
 435                         continue;
 436                 }
 437
 438                 if(!memcmp(address, &cache_ipv4_address[i], sizeof(*address))) {
 439                         return cache_ipv4_subnet[i];
 440                 }
 441         }
 442
 443         // Search all subnets for a matching one
 444
 445         for(n = subnet_tree->head; n; n = n->next) {
 446                 p = n->data;
 447
 448                 if(!p || p->type != SUBNET_IPV4) {
 449                         continue;
 450                 }
 451
 452                 if(!maskcmp(address, &p->net.ipv4.address, p->net.ipv4.prefixlength)) {
 453                         r = p;
 454
 455                         if(p->owner->status.reachable) {
 456                                 break;
 457                         }
 458                 }
 459         }
 460
 461         // Cache the result
 462
 463         cache_ipv4_slot = !cache_ipv4_slot;
 464         memcpy(&cache_ipv4_address[cache_ipv4_slot], address, sizeof(*address));
 465         cache_ipv4_subnet[cache_ipv4_slot] = r;
 466         cache_ipv4_valid[cache_ipv4_slot] = true;
 467
 468         return r;
 469 }
 470
 471 subnet_t *lookup_subnet_ipv6(const ipv6_t *address) {
 472         subnet_t *p, *r = NULL;
 473         avl_node_t *n;
 474         int i;
 475
 476         // Check if this address is cached
 477
 478         for(i = 0; i < 2; i++) {
 479                 if(!cache_ipv6_valid[i]) {
 480                         continue;
 481                 }
 482
 483                 if(!memcmp(address, &cache_ipv6_address[i], sizeof(*address))) {
 484                         return cache_ipv6_subnet[i];
 485                 }
 486         }
 487
 488         // Search all subnets for a matching one
 489
 490         for(n = subnet_tree->head; n; n = n->next) {
 491                 p = n->data;
 492
 493                 if(!p || p->type != SUBNET_IPV6) {
 494                         continue;
 495                 }
 496
 497                 if(!maskcmp(address, &p->net.ipv6.address, p->net.ipv6.prefixlength)) {
 498                         r = p;
 499
 500                         if(p->owner->status.reachable) {
 501                                 break;
 502                         }
 503                 }
 504         }
 505
 506         // Cache the result
 507
 508         cache_ipv6_slot = !cache_ipv6_slot;
 509         memcpy(&cache_ipv6_address[cache_ipv6_slot], address, sizeof(*address));
 510         cache_ipv6_subnet[cache_ipv6_slot] = r;
 511         cache_ipv6_valid[cache_ipv6_slot] = true;
 512
 513         return r;
 514 }
 515
 516 void subnet_update(node_t *owner, subnet_t *subnet, bool up) {
 517         avl_node_t *node;
 518         int i;
 519         char *envp[10] = {NULL};
 520         char netstr[MAXNETSTR];
 521         char *name, *address, *port;
 522         char empty[] = "";
 523
 524         // Prepare environment variables to be passed to the script
 525
 526         xasprintf(&envp[0], "NETNAME=%s", netname ? netname : "");
 527         xasprintf(&envp[1], "DEVICE=%s", device ? device : "");
 528         xasprintf(&envp[2], "INTERFACE=%s", iface ? iface : "");
 529         xasprintf(&envp[3], "NODE=%s", owner->name);
 530         xasprintf(&envp[4], "NAME=%s", myself->name);
 531
 532         if(owner != myself) {
 533                 sockaddr2str(&owner->address, &address, &port);
 534                 // 5 and 6 are reserved for SUBNET and WEIGHT
 535                 xasprintf(&envp[7], "REMOTEADDRESS=%s", address);
 536                 xasprintf(&envp[8], "REMOTEPORT=%s", port);
 537                 free(port);
 538                 free(address);
 539         }
 540
 541         name = up ? "subnet-up" : "subnet-down";
 542
 543         if(!subnet) {
 544                 for(node = owner->subnet_tree->head; node; node = node->next) {
 545                         subnet = node->data;
 546
 547                         if(!net2str(netstr, sizeof(netstr), subnet)) {
 548                                 continue;
 549                         }
 550
 551                         // Strip the weight from the subnet, and put it in its own environment variable
 552                         char *weight = strchr(netstr, '#');
 553
 554                         if(weight) {
 555                                 *weight++ = 0;
 556                         } else {
 557                                 weight = empty;
 558                         }
 559
 560                         // Prepare the SUBNET and WEIGHT variables
 561                         free(envp[5]);
 562                         free(envp[6]);
 563
 564                         xasprintf(&envp[5], "SUBNET=%s", netstr);
 565                         xasprintf(&envp[6], "WEIGHT=%s", weight);
 566
 567                         execute_script(name, envp);
 568                 }
 569         } else {
 570                 if(net2str(netstr, sizeof(netstr), subnet)) {
 571                         // Strip the weight from the subnet, and put it in its own environment variable
 572                         char *weight = strchr(netstr, '#');
 573
 574                         if(weight) {
 575                                 *weight++ = 0;
 576                         } else {
 577                                 weight = empty;
 578                         }
 579
 580                         // Prepare the SUBNET and WEIGHT variables
 581                         xasprintf(&envp[5], "SUBNET=%s", netstr);
 582                         xasprintf(&envp[6], "WEIGHT=%s", weight);
 583
 584                         execute_script(name, envp);
 585                 }
 586         }
 587
 588         for(i = 0; i < 9; i++) {
 589                 free(envp[i]);
 590         }
 591 }
 592
 593 void dump_subnets(void) {
 594         char netstr[MAXNETSTR];
 595         subnet_t *subnet;
 596         avl_node_t *node;
 597
 598         logger(LOG_DEBUG, "Subnet list:");
 599
 600         for(node = subnet_tree->head; node; node = node->next) {
 601                 subnet = node->data;
 602
 603                 if(!net2str(netstr, sizeof(netstr), subnet)) {
 604                         continue;
 605                 }
 606
 607                 logger(LOG_DEBUG, " %s owner %s", netstr, subnet->owner->name);
 608         }
 609
 610         logger(LOG_DEBUG, "End of subnet list.");
 611 }