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

   1 /*
   2     subnet.c -- handle subnet lookups and lists
   3     Copyright (C) 2000-2017 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 "splay_tree.h"
  24 #include "control_common.h"
  25 #include "hash.h"
  26 #include "logger.h"
  27 #include "net.h"
  28 #include "netutl.h"
  29 #include "node.h"
  30 #include "script.h"
  31 #include "subnet.h"
  32 #include "xalloc.h"
  33
  34 /* lists type of subnet */
  35 uint32_t hash_seed;
  36 splay_tree_t subnet_tree = {
  37         .compare = (splay_compare_t) subnet_compare,
  38         .delete = (splay_action_t) free_subnet,
  39 };
  40
  41 /* Subnet lookup cache */
  42
  43 static uint32_t wrapping_add32(uint32_t a, uint32_t b) {
  44         return (uint32_t)((uint64_t)a + b);
  45 }
  46
  47 static uint32_t wrapping_mul32(uint32_t a, uint32_t b) {
  48         return (uint32_t)((uint64_t)a * b);
  49 }
  50
  51 static uint32_t hash_function_ipv4_t(const ipv4_t *p) {
  52         /*
  53         This basic hash works because
  54         a) Most IPv4 networks routed via tinc are not /0
  55         b) Most IPv4 networks have more unique low order bits
  56         */
  57         uint16_t *halfwidth = (uint16_t *)p;
  58         uint32_t hash = hash_seed;
  59
  60 #if __BYTE_ORDER == __LITTLE_ENDIAN
  61         // 10.0.x.x/16 part
  62         hash = wrapping_add32(hash, wrapping_mul32(halfwidth[1], 0x9e370001U));
  63
  64         // x.x.0.[0-255] part
  65 #if SUBNET_HASH_SIZE >= 0x10000
  66         return hash ^ halfwidth[0];
  67 #else
  68         // ensure that we have a /24 with no collisions on 32bit
  69         return hash ^ ntohs(halfwidth[0]);
  70 #endif // _____LP64_____
  71 #else
  72         // 10.0.x.x/16 part
  73         hash = wrapping_add32(hash, wrapping_mul32(halfwidth[0], 0x9e370001U));
  74
  75         // x.x.0.[0-255] part (ntohs is nop on big endian)
  76         return hash ^ halfwidth[1];
  77 #endif // __BYTE_ORDER == __LITTLE_ENDIAN
  78 }
  79
  80
  81 static uint32_t hash_function_ipv6_t(const ipv6_t *p) {
  82         uint32_t *fullwidth = (uint32_t *)p;
  83         uint32_t hash = hash_seed;
  84
  85         for(int i = 0; i < 4; i++) {
  86                 hash += fullwidth[i];
  87                 hash = wrapping_mul32(hash, 0x9e370001U);
  88         }
  89
  90         return hash;
  91 }
  92
  93 static uint32_t hash_function_mac_t(const mac_t *p) {
  94         uint16_t *halfwidth = (uint16_t *)p;
  95         uint32_t hash = hash_seed;
  96
  97         for(int i = 0; i < 3; i++) {
  98                 hash += halfwidth[i];
  99                 hash = wrapping_mul32(hash, 0x9e370001U);
 100         }
 101
 102         return hash;
 103 }
 104
 105 hash_define(ipv4_t, SUBNET_HASH_SIZE)
 106 hash_define(ipv6_t, SUBNET_HASH_SIZE)
 107 hash_define(mac_t, SUBNET_HASH_SIZE)
 108
 109 hash_new(ipv4_t, ipv4_cache);
 110 hash_new(ipv6_t, ipv6_cache);
 111 hash_new(mac_t, mac_cache);
 112
 113
 114 void subnet_cache_flush_table(subnet_type_t stype) {
 115         // NOTE: a subnet type of SUBNET_TYPES can be used to clear all hash tables
 116
 117         if(stype != SUBNET_IPV6) { // ipv4
 118                 hash_clear(ipv4_t, &ipv4_cache);
 119         }
 120
 121         if(stype != SUBNET_IPV4) { // ipv6
 122                 hash_clear(ipv6_t, &ipv6_cache);
 123         }
 124
 125         hash_clear(mac_t, &mac_cache);
 126 }
 127
 128 /* Initialising trees */
 129
 130 void init_subnets(void) {
 131         hash_seed = (uint32_t)rand();
 132
 133         // tables need to be cleared on startup
 134         subnet_cache_flush_tables();
 135 }
 136
 137 void exit_subnets(void) {
 138         splay_empty_tree(&subnet_tree);
 139         subnet_cache_flush_tables();
 140 }
 141
 142 void init_subnet_tree(splay_tree_t *tree) {
 143         memset(tree, 0, sizeof(*tree));
 144         tree->compare = (splay_compare_t) subnet_compare;
 145 }
 146
 147 /* Allocating and freeing space for subnets */
 148
 149 subnet_t *new_subnet(void) {
 150         return xzalloc(sizeof(subnet_t));
 151 }
 152
 153 void free_subnet(subnet_t *subnet) {
 154         free(subnet);
 155 }
 156
 157 void subnet_cache_flush_tables(void) {
 158         // flushes all the tables
 159         hash_clear(ipv4_t, &ipv4_cache);
 160         hash_clear(ipv6_t, &ipv6_cache);
 161         hash_clear(mac_t, &mac_cache);
 162 }
 163
 164 void subnet_cache_flush(subnet_t *subnet) {
 165         switch(subnet->type) {
 166         case SUBNET_IPV4:
 167                 if(subnet->net.ipv4.prefixlength == 32) {
 168                         hash_delete(ipv4_t, &ipv4_cache, &subnet->net.ipv4.address);
 169                         return;
 170                 }
 171
 172                 break;
 173
 174         case SUBNET_IPV6:
 175                 if(subnet->net.ipv4.prefixlength == 128) {
 176                         hash_delete(ipv6_t, &ipv6_cache, &subnet->net.ipv6.address);
 177                         return;
 178                 }
 179
 180                 break;
 181
 182         case SUBNET_MAC:
 183                 hash_delete(mac_t, &mac_cache, &subnet->net.mac.address);
 184                 return;
 185         }
 186
 187         subnet_cache_flush_table(subnet->type);
 188 }
 189
 190 /* Adding and removing subnets */
 191
 192 void subnet_add(node_t *n, subnet_t *subnet) {
 193         subnet->owner = n;
 194
 195         splay_insert(&subnet_tree, subnet);
 196
 197         if(n) {
 198                 splay_insert(&n->subnet_tree, subnet);
 199         }
 200
 201         subnet_cache_flush(subnet);
 202 }
 203
 204 void subnet_del(node_t *n, subnet_t *subnet) {
 205         if(n) {
 206                 splay_delete(&n->subnet_tree, subnet);
 207         }
 208
 209         splay_delete(&subnet_tree, subnet);
 210
 211         subnet_cache_flush(subnet);
 212 }
 213
 214 /* Subnet lookup routines */
 215
 216 subnet_t *lookup_subnet(node_t *owner, const subnet_t *subnet) {
 217         return splay_search(&owner->subnet_tree, subnet);
 218 }
 219
 220 subnet_t *lookup_subnet_mac(const node_t *owner, const mac_t *address) {
 221         subnet_t *r = NULL;
 222
 223         // Check if this address is cached
 224
 225         if((r = hash_search(mac_t, &mac_cache, address))) {
 226                 return r;
 227         }
 228
 229         // Search all subnets for a matching one
 230
 231         for splay_each(subnet_t, p, owner ? &owner->subnet_tree : &subnet_tree) {
 232                 if(!p || p->type != SUBNET_MAC) {
 233                         continue;
 234                 }
 235
 236                 if(!memcmp(address, &p->net.mac.address, sizeof(*address))) {
 237                         r = p;
 238
 239                         if(!p->owner || p->owner->status.reachable) {
 240                                 break;
 241                         }
 242                 }
 243         }
 244
 245         // Cache the result
 246
 247         if(r) {
 248                 hash_insert(mac_t, &mac_cache, address, r);
 249         }
 250
 251         return r;
 252 }
 253
 254 subnet_t *lookup_subnet_ipv4(const ipv4_t *address) {
 255         subnet_t *r = NULL;
 256
 257         // Check if this address is cached
 258
 259         if((r = hash_search(ipv4_t, &ipv4_cache, address))) {
 260                 return r;
 261         }
 262
 263         // Search all subnets for a matching one
 264
 265         for splay_each(subnet_t, p, &subnet_tree) {
 266                 if(!p || p->type != SUBNET_IPV4) {
 267                         continue;
 268                 }
 269
 270                 if(!maskcmp(address, &p->net.ipv4.address, p->net.ipv4.prefixlength)) {
 271                         r = p;
 272
 273                         if(!p->owner || p->owner->status.reachable) {
 274                                 break;
 275                         }
 276                 }
 277         }
 278
 279         // Cache the result
 280
 281         if(r) {
 282                 hash_insert(ipv4_t, &ipv4_cache, address, r);
 283         }
 284
 285         return r;
 286 }
 287
 288 subnet_t *lookup_subnet_ipv6(const ipv6_t *address) {
 289         subnet_t *r = NULL;
 290
 291         // Check if this address is cached
 292
 293         if((r = hash_search(ipv6_t, &ipv6_cache, address))) {
 294                 return r;
 295         }
 296
 297         // Search all subnets for a matching one
 298
 299         for splay_each(subnet_t, p, &subnet_tree) {
 300                 if(!p || p->type != SUBNET_IPV6) {
 301                         continue;
 302                 }
 303
 304                 if(!maskcmp(address, &p->net.ipv6.address, p->net.ipv6.prefixlength)) {
 305                         r = p;
 306
 307                         if(!p->owner || p->owner->status.reachable) {
 308                                 break;
 309                         }
 310                 }
 311         }
 312
 313         // Cache the result
 314
 315         if(r) {
 316                 hash_insert(ipv6_t, &ipv6_cache, address, r);
 317         }
 318
 319         return r;
 320 }
 321
 322 void subnet_update(node_t *owner, subnet_t *subnet, bool up) {
 323         char netstr[MAXNETSTR];
 324         char *name, *address, *port;
 325         char empty[] = "";
 326
 327         // Prepare environment variables to be passed to the script
 328
 329         environment_t env;
 330         environment_init(&env);
 331         environment_add(&env, "NODE=%s", owner->name);
 332
 333         if(owner != myself) {
 334                 sockaddr2str(&owner->address, &address, &port);
 335                 environment_add(&env, "REMOTEADDRESS=%s", address);
 336                 environment_add(&env, "REMOTEPORT=%s", port);
 337                 free(port);
 338                 free(address);
 339         }
 340
 341         int env_subnet = environment_add(&env, NULL);
 342         int env_weight = environment_add(&env, NULL);
 343
 344         name = up ? "subnet-up" : "subnet-down";
 345
 346         if(!subnet) {
 347                 for splay_each(subnet_t, subnet, &owner->subnet_tree) {
 348                         if(!net2str(netstr, sizeof(netstr), subnet)) {
 349                                 continue;
 350                         }
 351
 352                         // Strip the weight from the subnet, and put it in its own environment variable
 353                         char *weight = strchr(netstr, '#');
 354
 355                         if(weight) {
 356                                 *weight++ = 0;
 357                         } else {
 358                                 weight = empty;
 359                         }
 360
 361                         // Prepare the SUBNET and WEIGHT variables
 362                         environment_update(&env, env_subnet, "SUBNET=%s", netstr);
 363                         environment_update(&env, env_weight, "WEIGHT=%s", weight);
 364
 365                         execute_script(name, &env);
 366                 }
 367         } else {
 368                 if(net2str(netstr, sizeof(netstr), subnet)) {
 369                         // Strip the weight from the subnet, and put it in its own environment variable
 370                         char *weight = strchr(netstr, '#');
 371
 372                         if(weight) {
 373                                 *weight++ = 0;
 374                         } else {
 375                                 weight = empty;
 376                         }
 377
 378                         // Prepare the SUBNET and WEIGHT variables
 379                         environment_update(&env, env_subnet, "SUBNET=%s", netstr);
 380                         environment_update(&env, env_weight, "WEIGHT=%s", weight);
 381
 382                         execute_script(name, &env);
 383                 }
 384         }
 385
 386         environment_exit(&env);
 387 }
 388
 389 bool dump_subnets(connection_t *c) {
 390         for splay_each(subnet_t, subnet, &subnet_tree) {
 391                 char netstr[MAXNETSTR];
 392
 393                 if(!net2str(netstr, sizeof(netstr), subnet)) {
 394                         continue;
 395                 }
 396
 397                 send_request(c, "%d %d %s %s",
 398                              CONTROL, REQ_DUMP_SUBNETS,
 399                              netstr, subnet->owner ? subnet->owner->name : "(broadcast)");
 400         }
 401
 402         return send_request(c, "%d %d", CONTROL, REQ_DUMP_SUBNETS);
 403 }