src/ippool.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2012  Intel Corporation. All rights reserved.
   6  *  Copyright (C) 2012  BMW Car IT GmbH. All rights reserved.
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20  *
  21  */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include <getopt.h>
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include <sys/errno.h>
  33 #include <sys/socket.h>
  34
  35 #include "connman.h"
  36
  37 struct address_info {
  38         int index;
  39         uint32_t start;
  40         uint32_t end;
  41
  42         unsigned int use_count;
  43         struct connman_ippool *pool;
  44 };
  45
  46 struct connman_ippool {
  47         unsigned int refcount;
  48
  49         struct address_info *info;
  50
  51         char *gateway;
  52         char *broadcast;
  53         char *start_ip;
  54         char *end_ip;
  55         char *subnet_mask;
  56
  57         ippool_collision_cb_t collision_cb;
  58         void *user_data;
  59 };
  60
  61 GSList *allocated_blocks;
  62 GHashTable *pool_hash;
  63
  64 static uint32_t last_block;
  65 static uint32_t block_16_bits;
  66 static uint32_t block_20_bits;
  67 static uint32_t block_24_bits;
  68 static uint32_t subnet_mask_24;
  69
  70 struct connman_ippool *
  71 __connman_ippool_ref_debug(struct connman_ippool *pool,
  72                                 const char *file, int line, const char *caller)
  73 {
  74         DBG("%p ref %d by %s:%d:%s()", pool, pool->refcount + 1,
  75                 file, line, caller);
  76
  77         __sync_fetch_and_add(&pool->refcount, 1);
  78
  79         return pool;
  80 }
  81
  82 void __connman_ippool_unref_debug(struct connman_ippool *pool,
  83                                 const char *file, int line, const char *caller)
  84 {
  85         if (pool == NULL)
  86                 return;
  87
  88         DBG("%p ref %d by %s:%d:%s()", pool, pool->refcount - 1,
  89                 file, line, caller);
  90
  91         if (__sync_fetch_and_sub(&pool->refcount, 1) != 1)
  92                 return;
  93
  94         g_hash_table_remove(pool_hash, pool);
  95 }
  96
  97 static char *get_ip(uint32_t ip)
  98 {
  99         struct in_addr addr;
 100
 101         addr.s_addr = htonl(ip);
 102
 103         return g_strdup(inet_ntoa(addr));
 104 }
 105
 106 static uint32_t next_block(uint32_t block)
 107 {
 108         uint32_t next;
 109
 110         /*
 111          * Return the next IP block within the private IP range
 112          *
 113          * 16-bit block 192.168.0.0 – 192.168.255.255
 114          * 20-bit block  172.16.0.0 –  172.31.255.255
 115          * 24-bit block    10.0.0.0 –  10.255.255.255
 116          */
 117
 118         next = (block & 0x0000ff00) >> 8;
 119         next += 1;
 120
 121         if (next == 255) {
 122                 if ((block & 0xffff0000) == block_16_bits) {
 123                         /*
 124                          * Reached the end of the 16 bit block, switch
 125                          * to the 20-bit block.
 126                          */
 127                         return block_20_bits;
 128                 }
 129
 130                 if ((block & 0xffff0000) >= block_20_bits) {
 131                         next = (block & 0x00ff0000) >> 16;
 132                         if (next >= 16 && next < 32)
 133                                 next += 1;
 134
 135                         if (next == 32) {
 136                                 /*
 137                                  * Reached the end of the 20 bit
 138                                  * block, switch to the 24-bit block.
 139                                  */
 140                                 return block_24_bits;
 141                         }
 142
 143                         return (block & 0xff000000) |
 144                                 ((next << 16) & 0x00ff0000);
 145                 }
 146
 147                 if ((block & 0xff000000) == block_24_bits) {
 148                         next = (block & 0x00ff0000) >> 16;
 149                         if (next < 255)
 150                                 next += 1;
 151
 152                         if (next == 255) {
 153                                 /*
 154                                  * Reached the end of the 24 bit
 155                                  * block, switch to the 16-bit block.
 156                                  */
 157                                 return block_16_bits;
 158                         }
 159
 160                         return (block & 0xff000000) |
 161                                 ((next << 16) & 0x00ff0000);
 162                 }
 163         }
 164
 165         return (block & 0xffff0000) | ((next << 8) & 0x0000ff00);
 166 }
 167
 168 static uint32_t get_free_block(unsigned int size)
 169 {
 170         struct address_info *info;
 171         uint32_t block;
 172         GSList *list;
 173         connman_bool_t collision;
 174
 175         /*
 176          * Instead starting always from the 16 bit block, we start
 177          * from the last assigned block. This is a simple optimimazion
 178          * for the case where a lot of blocks have been assigned, e.g.
 179          * the first half of the private IP pool is in use and a new
 180          * we need to find a new block.
 181          *
 182          * To only thing we have to make sure is that we terminated if
 183          * there is no block left.
 184          */
 185         if (last_block == 0)
 186                 block = block_16_bits;
 187         else
 188                 block = next_block(last_block);
 189
 190         do {
 191                 collision = FALSE;
 192                 for (list = allocated_blocks; list != NULL; list = list->next) {
 193                         info = list->data;
 194
 195                         if (info->start <= block && block <= info->end) {
 196                                 collision = TRUE;
 197                                 break;
 198                         }
 199                 }
 200
 201                 if (collision == FALSE)
 202                         return block;
 203
 204                 block = next_block(block);
 205         } while (block != last_block);
 206
 207         return 0;
 208 }
 209
 210 static struct address_info *lookup_info(int index, uint32_t start)
 211 {
 212         GSList *list;
 213
 214         for (list = allocated_blocks; list != NULL; list = list->next) {
 215                 struct address_info *info = list->data;
 216
 217                 if (info->index == index && info->start == start)
 218                         return info;
 219         }
 220
 221         return NULL;
 222 }
 223
 224 static connman_bool_t is_private_address(uint32_t address)
 225 {
 226         unsigned int a, b;
 227
 228         a = (address & 0xff000000) >> 24;
 229         b = (address & 0x00ff0000) >> 16;
 230
 231         if (a == 10 || (a == 192 && b == 168) ||
 232                                         (a == 172 && (b >= 16 && b <= 31)))
 233                 return TRUE;
 234
 235         return FALSE;
 236 }
 237
 238 void __connman_ippool_newaddr(int index, const char *address,
 239                                 unsigned char prefixlen)
 240 {
 241         struct address_info *info, *it;
 242         struct in_addr inp;
 243         uint32_t start, end, mask;
 244         GSList *list;
 245
 246         if (inet_aton(address, &inp) == 0)
 247                 return;
 248
 249         start = ntohl(inp.s_addr);
 250         if (is_private_address(start) == FALSE)
 251                 return;
 252
 253         if (prefixlen >= 32)
 254                 mask = 0xffffffff;
 255         else
 256                 mask = ~(0xffffffff >> prefixlen);
 257
 258         start = start & mask;
 259         end = start | ~mask;
 260
 261         info = lookup_info(index, start);
 262         if (info != NULL)
 263                 goto update;
 264
 265         info = g_try_new0(struct address_info, 1);
 266         if (info == NULL)
 267                 return;
 268
 269         info->index = index;
 270         info->start = start;
 271         info->end = end;
 272
 273         allocated_blocks = g_slist_prepend(allocated_blocks, info);
 274
 275 update:
 276         info->use_count = info->use_count + 1;
 277
 278         if (info->use_count > 1 || info->pool != NULL) {
 279                 /*
 280                  * We need only to check for the first IP in a block for
 281                  * collisions.
 282                  */
 283                 return;
 284         }
 285
 286         for (list = allocated_blocks; list != NULL; list = list->next) {
 287                 it = list->data;
 288
 289                 if (it == info)
 290                         continue;
 291
 292                 if (!(it->start <= info->start || info->start <= it->end))
 293                         continue;
 294
 295                 if (it->pool != NULL && it->pool->collision_cb != NULL)
 296                         it->pool->collision_cb(it->pool, it->pool->user_data);
 297
 298                 return;
 299         }
 300 }
 301
 302 void __connman_ippool_deladdr(int index, const char *address,
 303                                 unsigned char prefixlen)
 304 {
 305         struct address_info *info;
 306         struct in_addr inp;
 307         uint32_t start, mask;
 308
 309         if (inet_aton(address, &inp) == 0)
 310                 return;
 311
 312         start = ntohl(inp.s_addr);
 313         if (is_private_address(start) == FALSE)
 314                 return;
 315
 316         mask = ~(0xffffffff >> prefixlen);
 317         start = start & mask;
 318
 319         info = lookup_info(index, start);
 320         if (info == NULL) {
 321                 /* In theory this should never happen */
 322                 connman_error("Inconsistent IP pool management (start not found)");
 323                 return;
 324         }
 325
 326         info->use_count = info->use_count - 1;
 327         if (info->pool != NULL)
 328                 return;
 329
 330         if (info->use_count > 0)
 331                 return;
 332
 333         allocated_blocks = g_slist_remove(allocated_blocks, info);
 334 }
 335
 336 struct connman_ippool *__connman_ippool_create(int index,
 337                                         unsigned int start,
 338                                         unsigned int range,
 339                                         ippool_collision_cb_t collision_cb,
 340                                         void *user_data)
 341 {
 342         struct connman_ippool *pool;
 343         struct address_info *info;
 344         uint32_t block;
 345
 346         DBG("");
 347
 348         /*
 349          * The range is at max 255 and we don't support overlapping
 350          * blocks.
 351          */
 352         if (start + range > 254) {
 353                 connman_error("IP pool does not support pool size larger than 254");
 354                 return NULL;
 355         }
 356
 357         block = get_free_block(start + range);
 358         if (block == 0) {
 359                 connman_warn("Could not find a free IP block");
 360                 return NULL;
 361         }
 362
 363         pool = g_try_new0(struct connman_ippool, 1);
 364         if (pool == NULL)
 365                 return NULL;
 366
 367         info = g_try_new0(struct address_info, 1);
 368         if (info == NULL) {
 369                 g_free(pool);
 370                 return NULL;
 371         }
 372
 373         last_block = block;
 374
 375         info->index = index;
 376         info->start = block;
 377         info->end = block + range;
 378
 379         pool->refcount = 1;
 380         pool->info = info;
 381         pool->collision_cb = collision_cb;
 382         pool->user_data = user_data;
 383
 384         info->pool = pool;
 385
 386         if (range == 0)
 387                 range = 1;
 388
 389         pool->gateway = get_ip(info->start + 1);
 390         pool->broadcast = get_ip(info->start + 255);
 391         pool->subnet_mask = get_ip(subnet_mask_24);
 392         pool->start_ip = get_ip(block + start);
 393         pool->end_ip = get_ip(block + start + range);
 394
 395         allocated_blocks = g_slist_prepend(allocated_blocks, info);
 396         g_hash_table_insert(pool_hash, pool, pool);
 397
 398         return pool;
 399 }
 400
 401 const char *__connman_ippool_get_gateway(struct connman_ippool *pool)
 402 {
 403         return pool->gateway;
 404 }
 405
 406 const char *__connman_ippool_get_broadcast(struct connman_ippool *pool)
 407 {
 408         return pool->broadcast;
 409 }
 410
 411 const char *__connman_ippool_get_start_ip(struct connman_ippool *pool)
 412 {
 413         return pool->start_ip;
 414 }
 415
 416 const char *__connman_ippool_get_end_ip(struct connman_ippool *pool)
 417 {
 418         return pool->end_ip;
 419 }
 420
 421 const char *__connman_ippool_get_subnet_mask(struct connman_ippool *pool)
 422 {
 423         return pool->subnet_mask;
 424 }
 425
 426 static void pool_free(gpointer data)
 427 {
 428         struct connman_ippool *pool = data;
 429
 430         if (pool->info != NULL) {
 431                 allocated_blocks = g_slist_remove(allocated_blocks, pool->info);
 432                 g_free(pool->info);
 433         }
 434
 435         g_free(pool->gateway);
 436         g_free(pool->broadcast);
 437         g_free(pool->start_ip);
 438         g_free(pool->end_ip);
 439         g_free(pool->subnet_mask);
 440
 441         g_free(pool);
 442 }
 443
 444 int __connman_ippool_init(void)
 445 {
 446         DBG("");
 447
 448         block_16_bits = ntohl(inet_addr("192.168.0.0"));
 449         block_20_bits = ntohl(inet_addr("172.16.0.0"));
 450         block_24_bits = ntohl(inet_addr("10.0.0.0"));
 451         subnet_mask_24 = ntohl(inet_addr("255.255.255.0"));
 452
 453         pool_hash = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL,
 454                                         pool_free);
 455
 456         return 0;
 457 }
 458
 459 void __connman_ippool_cleanup(void)
 460 {
 461         DBG("");
 462
 463         g_hash_table_destroy(pool_hash);
 464         pool_hash = NULL;
 465
 466         g_slist_free(allocated_blocks);
 467         last_block = 0;
 468         allocated_blocks = NULL;
 469 }