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