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
 134 void exit_subnets(void) {
 135         splay_empty_tree(&subnet_tree);
 136         subnet_cache_flush_tables();
 137 }
 138
 139 void init_subnet_tree(splay_tree_t *tree) {
 140         memset(tree, 0, sizeof(*tree));
 141         tree->compare = (splay_compare_t) subnet_compare;
 142 }
 143
 144 /* Allocating and freeing space for subnets */
 145
 146 subnet_t *new_subnet(void) {
 147         return xzalloc(sizeof(subnet_t));
 148 }
 149
 150 void free_subnet(subnet_t *subnet) {
 151         free(subnet);
 152 }
 153
 154 void subnet_cache_flush_tables(void) {
 155         // flushes all the tables
 156         hash_clear(ipv4_t, &ipv4_cache);
 157         hash_clear(ipv6_t, &ipv6_cache);
 158         hash_clear(mac_t, &mac_cache);
 159 }
 160
 161 void subnet_cache_flush(subnet_t *subnet) {
 162         switch(subnet->type) {
 163         case SUBNET_IPV4:
 164                 if(subnet->net.ipv4.prefixlength == 32) {
 165                         hash_delete(ipv4_t, &ipv4_cache, &subnet->net.ipv4.address);
 166                         return;
 167                 }
 168
 169                 break;
 170
 171         case SUBNET_IPV6:
 172                 if(subnet->net.ipv4.prefixlength == 128) {
 173                         hash_delete(ipv6_t, &ipv6_cache, &subnet->net.ipv6.address);
 174                         return;
 175                 }
 176
 177                 break;
 178
 179         case SUBNET_MAC:
 180                 hash_delete(mac_t, &mac_cache, &subnet->net.mac.address);
 181                 return;
 182         }
 183
 184         subnet_cache_flush_table(subnet->type);
 185 }
 186
 187 /* Adding and removing subnets */
 188
 189 void subnet_add(node_t *n, subnet_t *subnet) {
 190         subnet->owner = n;
 191
 192         splay_insert(&subnet_tree, subnet);
 193
 194         if(n) {
 195                 splay_insert(&n->subnet_tree, subnet);
 196         }
 197
 198         subnet_cache_flush(subnet);
 199 }
 200
 201 void subnet_del(node_t *n, subnet_t *subnet) {
 202         if(n) {
 203                 splay_delete(&n->subnet_tree, subnet);
 204         }
 205
 206         splay_delete(&subnet_tree, subnet);
 207
 208         subnet_cache_flush(subnet);
 209 }
 210
 211 /* Subnet lookup routines */
 212
 213 subnet_t *lookup_subnet(node_t *owner, const subnet_t *subnet) {
 214         return splay_search(&owner->subnet_tree, subnet);
 215 }
 216
 217 subnet_t *lookup_subnet_mac(const node_t *owner, const mac_t *address) {
 218         subnet_t *r = NULL;
 219
 220         // Check if this address is cached
 221
 222         if((r = hash_search(mac_t, &mac_cache, address))) {
 223                 return r;
 224         }
 225
 226         // Search all subnets for a matching one
 227
 228         for splay_each(subnet_t, p, owner ? &owner->subnet_tree : &subnet_tree) {
 229                 if(!p || p->type != SUBNET_MAC) {
 230                         continue;
 231                 }
 232
 233                 if(!memcmp(address, &p->net.mac.address, sizeof(*address))) {
 234                         r = p;
 235
 236                         if(!p->owner || p->owner->status.reachable) {
 237                                 break;
 238                         }
 239                 }
 240         }
 241
 242         // Cache the result
 243
 244         if(r) {
 245                 hash_insert(mac_t, &mac_cache, address, r);
 246         }
 247
 248         return r;
 249 }
 250
 251 subnet_t *lookup_subnet_ipv4(const ipv4_t *address) {
 252         subnet_t *r = NULL;
 253
 254         // Check if this address is cached
 255
 256         if((r = hash_search(ipv4_t, &ipv4_cache, address))) {
 257                 return r;
 258         }
 259
 260         // Search all subnets for a matching one
 261
 262         for splay_each(subnet_t, p, &subnet_tree) {
 263                 if(!p || p->type != SUBNET_IPV4) {
 264                         continue;
 265                 }
 266
 267                 if(!maskcmp(address, &p->net.ipv4.address, p->net.ipv4.prefixlength)) {
 268                         r = p;
 269
 270                         if(!p->owner || p->owner->status.reachable) {
 271                                 break;
 272                         }
 273                 }
 274         }
 275
 276         // Cache the result
 277
 278         if(r) {
 279                 hash_insert(ipv4_t, &ipv4_cache, address, r);
 280         }
 281
 282         return r;
 283 }
 284
 285 subnet_t *lookup_subnet_ipv6(const ipv6_t *address) {
 286         subnet_t *r = NULL;
 287
 288         // Check if this address is cached
 289
 290         if((r = hash_search(ipv6_t, &ipv6_cache, address))) {
 291                 return r;
 292         }
 293
 294         // Search all subnets for a matching one
 295
 296         for splay_each(subnet_t, p, &subnet_tree) {
 297                 if(!p || p->type != SUBNET_IPV6) {
 298                         continue;
 299                 }
 300
 301                 if(!maskcmp(address, &p->net.ipv6.address, p->net.ipv6.prefixlength)) {
 302                         r = p;
 303
 304                         if(!p->owner || p->owner->status.reachable) {
 305                                 break;
 306                         }
 307                 }
 308         }
 309
 310         // Cache the result
 311
 312         if(r) {
 313                 hash_insert(ipv6_t, &ipv6_cache, address, r);
 314         }
 315
 316         return r;
 317 }
 318
 319 void subnet_update(node_t *owner, subnet_t *subnet, bool up) {
 320         char netstr[MAXNETSTR];
 321         char *name, *address, *port;
 322         char empty[] = "";
 323
 324         // Prepare environment variables to be passed to the script
 325
 326         environment_t env;
 327         environment_init(&env);
 328         environment_add(&env, "NODE=%s", owner->name);
 329
 330         if(owner != myself) {
 331                 sockaddr2str(&owner->address, &address, &port);
 332                 environment_add(&env, "REMOTEADDRESS=%s", address);
 333                 environment_add(&env, "REMOTEPORT=%s", port);
 334                 free(port);
 335                 free(address);
 336         }
 337
 338         int env_subnet = environment_add(&env, NULL);
 339         int env_weight = environment_add(&env, NULL);
 340
 341         name = up ? "subnet-up" : "subnet-down";
 342
 343         if(!subnet) {
 344                 for splay_each(subnet_t, subnet, &owner->subnet_tree) {
 345                         if(!net2str(netstr, sizeof(netstr), subnet)) {
 346                                 continue;
 347                         }
 348
 349                         // Strip the weight from the subnet, and put it in its own environment variable
 350                         char *weight = strchr(netstr, '#');
 351
 352                         if(weight) {
 353                                 *weight++ = 0;
 354                         } else {
 355                                 weight = empty;
 356                         }
 357
 358                         // Prepare the SUBNET and WEIGHT variables
 359                         environment_update(&env, env_subnet, "SUBNET=%s", netstr);
 360                         environment_update(&env, env_weight, "WEIGHT=%s", weight);
 361
 362                         execute_script(name, &env);
 363                 }
 364         } else {
 365                 if(net2str(netstr, sizeof(netstr), subnet)) {
 366                         // Strip the weight from the subnet, and put it in its own environment variable
 367                         char *weight = strchr(netstr, '#');
 368
 369                         if(weight) {
 370                                 *weight++ = 0;
 371                         } else {
 372                                 weight = empty;
 373                         }
 374
 375                         // Prepare the SUBNET and WEIGHT variables
 376                         environment_update(&env, env_subnet, "SUBNET=%s", netstr);
 377                         environment_update(&env, env_weight, "WEIGHT=%s", weight);
 378
 379                         execute_script(name, &env);
 380                 }
 381         }
 382
 383         environment_exit(&env);
 384 }
 385
 386 bool dump_subnets(connection_t *c) {
 387         for splay_each(subnet_t, subnet, &subnet_tree) {
 388                 char netstr[MAXNETSTR];
 389
 390                 if(!net2str(netstr, sizeof(netstr), subnet)) {
 391                         continue;
 392                 }
 393
 394                 send_request(c, "%d %d %s %s",
 395                              CONTROL, REQ_DUMP_SUBNETS,
 396                              netstr, subnet->owner ? subnet->owner->name : "(broadcast)");
 397         }
 398
 399         return send_request(c, "%d %d", CONTROL, REQ_DUMP_SUBNETS);
 400 }