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

   1 /*
   2     subnet.c -- handle subnet lookups and lists
   3     Copyright (C) 2000-2022 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 "crypto.h"
  26 #include "hash.h"
  27 #include "logger.h"
  28 #include "net.h"
  29 #include "netutl.h"
  30 #include "node.h"
  31 #include "script.h"
  32 #include "subnet.h"
  33 #include "xalloc.h"
  34 #include "sandbox.h"
  35
  36 /* lists type of subnet */
  37 uint32_t hash_seed;
  38 splay_tree_t subnet_tree = {
  39         .compare = (splay_compare_t) subnet_compare,
  40         .delete = (splay_action_t) free_subnet,
  41 };
  42
  43 /* Subnet lookup cache */
  44
  45 static uint32_t wrapping_add32(uint32_t a, uint32_t b) {
  46         return (uint32_t)((uint64_t)a + b);
  47 }
  48
  49 static uint32_t wrapping_mul32(uint32_t a, uint32_t b) {
  50         return (uint32_t)((uint64_t)a * b);
  51 }
  52
  53 static uint32_t hash_function_ipv4_t(const ipv4_t *p) {
  54         /*
  55         This basic hash works because
  56         a) Most IPv4 networks routed via tinc are not /0
  57         b) Most IPv4 networks have more unique low order bits
  58         */
  59         uint16_t *halfwidth = (uint16_t *)p;
  60         uint32_t hash = hash_seed;
  61
  62 #if __BYTE_ORDER == __LITTLE_ENDIAN
  63         // 10.0.x.x/16 part
  64         hash = wrapping_add32(hash, wrapping_mul32(halfwidth[1], 0x9e370001U));
  65
  66         // x.x.0.[0-255] part
  67 #if SUBNET_HASH_SIZE >= 0x10000
  68         return hash ^ halfwidth[0];
  69 #else
  70         // ensure that we have a /24 with no collisions on 32bit
  71         return hash ^ ntohs(halfwidth[0]);
  72 #endif // _____LP64_____
  73 #else
  74         // 10.0.x.x/16 part
  75         hash = wrapping_add32(hash, wrapping_mul32(halfwidth[0], 0x9e370001U));
  76
  77         // x.x.0.[0-255] part (ntohs is nop on big endian)
  78         return hash ^ halfwidth[1];
  79 #endif // __BYTE_ORDER == __LITTLE_ENDIAN
  80 }
  81
  82
  83 static uint32_t hash_function_ipv6_t(const ipv6_t *p) {
  84         uint32_t *fullwidth = (uint32_t *)p;
  85         uint32_t hash = hash_seed;
  86
  87         for(int i = 0; i < 4; i++) {
  88                 hash = wrapping_add32(hash, fullwidth[i]);
  89                 hash = wrapping_mul32(hash, 0x9e370001U);
  90         }
  91
  92         return hash;
  93 }
  94
  95 static uint32_t hash_function_mac_t(const mac_t *p) {
  96         uint16_t *halfwidth = (uint16_t *)p;
  97         uint32_t hash = hash_seed;
  98
  99         for(int i = 0; i < 3; i++) {
 100                 hash = wrapping_add32(hash, halfwidth[i]);
 101                 hash = wrapping_mul32(hash, 0x9e370001U);
 102         }
 103
 104         return hash;
 105 }
 106
 107 hash_define(ipv4_t, SUBNET_HASH_SIZE)
 108 hash_define(ipv6_t, SUBNET_HASH_SIZE)
 109 hash_define(mac_t, SUBNET_HASH_SIZE)
 110
 111 hash_new(ipv4_t, ipv4_cache);
 112 hash_new(ipv6_t, ipv6_cache);
 113 hash_new(mac_t, mac_cache);
 114
 115
 116 void subnet_cache_flush_table(subnet_type_t stype) {
 117         // NOTE: a subnet type of SUBNET_TYPES can be used to clear all hash tables
 118
 119         if(stype != SUBNET_IPV6) { // ipv4
 120                 hash_clear(ipv4_t, &ipv4_cache);
 121         }
 122
 123         if(stype != SUBNET_IPV4) { // ipv6
 124                 hash_clear(ipv6_t, &ipv6_cache);
 125         }
 126
 127         hash_clear(mac_t, &mac_cache);
 128 }
 129
 130 /* Initialising trees */
 131
 132 void init_subnets(void) {
 133         hash_seed = prng(UINT32_MAX);
 134
 135         // tables need to be cleared on startup
 136         subnet_cache_flush_tables();
 137 }
 138
 139 void exit_subnets(void) {
 140         splay_empty_tree(&subnet_tree);
 141         subnet_cache_flush_tables();
 142 }
 143
 144 void init_subnet_tree(splay_tree_t *tree) {
 145         memset(tree, 0, sizeof(*tree));
 146         tree->compare = (splay_compare_t) subnet_compare;
 147 }
 148
 149 /* Allocating and freeing space for subnets */
 150
 151 subnet_t *new_subnet(void) {
 152         return xzalloc(sizeof(subnet_t));
 153 }
 154
 155 void free_subnet(subnet_t *subnet) {
 156         free(subnet);
 157 }
 158
 159 void subnet_cache_flush_tables(void) {
 160         // flushes all the tables
 161         hash_clear(ipv4_t, &ipv4_cache);
 162         hash_clear(ipv6_t, &ipv6_cache);
 163         hash_clear(mac_t, &mac_cache);
 164 }
 165
 166 static void subnet_cache_flush(subnet_t *subnet) {
 167         switch(subnet->type) {
 168         case SUBNET_IPV4:
 169                 if(subnet->net.ipv4.prefixlength == 32) {
 170                         hash_delete(ipv4_t, &ipv4_cache, &subnet->net.ipv4.address);
 171                         return;
 172                 }
 173
 174                 break;
 175
 176         case SUBNET_IPV6:
 177                 if(subnet->net.ipv4.prefixlength == 128) {
 178                         hash_delete(ipv6_t, &ipv6_cache, &subnet->net.ipv6.address);
 179                         return;
 180                 }
 181
 182                 break;
 183
 184         case SUBNET_MAC:
 185                 hash_delete(mac_t, &mac_cache, &subnet->net.mac.address);
 186                 return;
 187         }
 188
 189         subnet_cache_flush_table(subnet->type);
 190 }
 191
 192 /* Adding and removing subnets */
 193
 194 void subnet_add(node_t *n, subnet_t *subnet) {
 195         subnet->owner = n;
 196
 197         splay_insert(&subnet_tree, subnet);
 198
 199         if(n) {
 200                 splay_insert(&n->subnet_tree, subnet);
 201         }
 202
 203         subnet_cache_flush(subnet);
 204 }
 205
 206 void subnet_del(node_t *n, subnet_t *subnet) {
 207         if(n) {
 208                 splay_delete(&n->subnet_tree, subnet);
 209         }
 210
 211         splay_delete(&subnet_tree, subnet);
 212
 213         subnet_cache_flush(subnet);
 214 }
 215
 216 /* Subnet lookup routines */
 217
 218 subnet_t *lookup_subnet(node_t *owner, const subnet_t *subnet) {
 219         return splay_search(&owner->subnet_tree, subnet);
 220 }
 221
 222 subnet_t *lookup_subnet_mac(const node_t *owner, const mac_t *address) {
 223         subnet_t *r = NULL;
 224
 225         // Check if this address is cached
 226
 227         if((r = hash_search(mac_t, &mac_cache, address))) {
 228                 return r;
 229         }
 230
 231         // Search all subnets for a matching one
 232
 233         for splay_each(subnet_t, p, owner ? &owner->subnet_tree : &subnet_tree) {
 234                 if(!p || p->type != SUBNET_MAC) {
 235                         continue;
 236                 }
 237
 238                 if(!memcmp(address, &p->net.mac.address, sizeof(*address))) {
 239                         r = p;
 240
 241                         if(!p->owner || p->owner->status.reachable) {
 242                                 break;
 243                         }
 244                 }
 245         }
 246
 247         // Cache the result
 248
 249         if(r) {
 250                 hash_insert(mac_t, &mac_cache, address, r);
 251         }
 252
 253         return r;
 254 }
 255
 256 subnet_t *lookup_subnet_ipv4(const ipv4_t *address) {
 257         subnet_t *r = NULL;
 258
 259         // Check if this address is cached
 260
 261         if((r = hash_search(ipv4_t, &ipv4_cache, address))) {
 262                 return r;
 263         }
 264
 265         // Search all subnets for a matching one
 266
 267         for splay_each(subnet_t, p, &subnet_tree) {
 268                 if(!p || p->type != SUBNET_IPV4) {
 269                         continue;
 270                 }
 271
 272                 if(!maskcmp(address, &p->net.ipv4.address, p->net.ipv4.prefixlength)) {
 273                         r = p;
 274
 275                         if(!p->owner || p->owner->status.reachable) {
 276                                 break;
 277                         }
 278                 }
 279         }
 280
 281         // Cache the result
 282
 283         if(r) {
 284                 hash_insert(ipv4_t, &ipv4_cache, address, r);
 285         }
 286
 287         return r;
 288 }
 289
 290 subnet_t *lookup_subnet_ipv6(const ipv6_t *address) {
 291         subnet_t *r = NULL;
 292
 293         // Check if this address is cached
 294
 295         if((r = hash_search(ipv6_t, &ipv6_cache, address))) {
 296                 return r;
 297         }
 298
 299         // Search all subnets for a matching one
 300
 301         for splay_each(subnet_t, p, &subnet_tree) {
 302                 if(!p || p->type != SUBNET_IPV6) {
 303                         continue;
 304                 }
 305
 306                 if(!maskcmp(address, &p->net.ipv6.address, p->net.ipv6.prefixlength)) {
 307                         r = p;
 308
 309                         if(!p->owner || p->owner->status.reachable) {
 310                                 break;
 311                         }
 312                 }
 313         }
 314
 315         // Cache the result
 316
 317         if(r) {
 318                 hash_insert(ipv6_t, &ipv6_cache, address, r);
 319         }
 320
 321         return r;
 322 }
 323
 324 void subnet_update(node_t *owner, subnet_t *subnet, bool up) {
 325         if(!sandbox_can(START_PROCESSES, RIGHT_NOW)) {
 326                 return;
 327         }
 328
 329         char netstr[MAXNETSTR];
 330         char *address, *port;
 331         char empty[] = "";
 332
 333         // Prepare environment variables to be passed to the script
 334
 335         environment_t env;
 336         environment_init(&env);
 337         environment_add(&env, "NODE=%s", owner->name);
 338
 339         if(owner != myself) {
 340                 sockaddr2str(&owner->address, &address, &port);
 341                 environment_add(&env, "REMOTEADDRESS=%s", address);
 342                 environment_add(&env, "REMOTEPORT=%s", port);
 343                 free(port);
 344                 free(address);
 345         }
 346
 347         int env_subnet = environment_add(&env, NULL);
 348         int env_weight = environment_add(&env, NULL);
 349
 350         const char *name = up ? "subnet-up" : "subnet-down";
 351
 352         if(!subnet) {
 353                 for splay_each(subnet_t, subnet, &owner->subnet_tree) {
 354                         if(!net2str(netstr, sizeof(netstr), subnet)) {
 355                                 continue;
 356                         }
 357
 358                         // Strip the weight from the subnet, and put it in its own environment variable
 359                         char *weight = strchr(netstr, '#');
 360
 361                         if(weight) {
 362                                 *weight++ = 0;
 363                         } else {
 364                                 weight = empty;
 365                         }
 366
 367                         // Prepare the SUBNET and WEIGHT variables
 368                         environment_update(&env, env_subnet, "SUBNET=%s", netstr);
 369                         environment_update(&env, env_weight, "WEIGHT=%s", weight);
 370
 371                         execute_script(name, &env);
 372                 }
 373         } else {
 374                 if(net2str(netstr, sizeof(netstr), subnet)) {
 375                         // Strip the weight from the subnet, and put it in its own environment variable
 376                         char *weight = strchr(netstr, '#');
 377
 378                         if(weight) {
 379                                 *weight++ = 0;
 380                         } else {
 381                                 weight = empty;
 382                         }
 383
 384                         // Prepare the SUBNET and WEIGHT variables
 385                         environment_update(&env, env_subnet, "SUBNET=%s", netstr);
 386                         environment_update(&env, env_weight, "WEIGHT=%s", weight);
 387
 388                         execute_script(name, &env);
 389                 }
 390         }
 391
 392         environment_exit(&env);
 393 }
 394
 395 bool dump_subnets(connection_t *c) {
 396         for splay_each(subnet_t, subnet, &subnet_tree) {
 397                 char netstr[MAXNETSTR];
 398
 399                 if(!net2str(netstr, sizeof(netstr), subnet)) {
 400                         continue;
 401                 }
 402
 403                 send_request(c, "%d %d %s %s",
 404                              CONTROL, REQ_DUMP_SUBNETS,
 405                              netstr, subnet->owner ? subnet->owner->name : "(broadcast)");
 406         }
 407
 408         return send_request(c, "%d %d", CONTROL, REQ_DUMP_SUBNETS);
 409 }