src/resolver.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2010  Intel Corporation. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  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
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <errno.h>
  28 #include <fcntl.h>
  29 #include <unistd.h>
  30 #include <string.h>
  31 #include <sys/stat.h>
  32 #include <resolv.h>
  33
  34 #include "connman.h"
  35
  36 #define RESOLVER_FLAG_PUBLIC (1 << 0)
  37
  38 struct entry_data {
  39         struct connman_resolver *resolver;
  40         char *interface;
  41         char *domain;
  42         char *server;
  43         unsigned int flags;
  44 };
  45
  46 static GSList *entry_list = NULL;
  47 static GSList *resolver_list = NULL;
  48
  49 static void remove_entries(GSList *entries)
  50 {
  51         GSList *list;
  52
  53         for (list = entries; list; list = list->next) {
  54                 struct entry_data *entry = list->data;
  55                 struct connman_resolver *resolver = entry->resolver;
  56
  57                 entry_list = g_slist_remove(entry_list, entry);
  58
  59                 if (resolver && resolver->remove)
  60                         resolver->remove(entry->interface, entry->domain,
  61                                                                 entry->server);
  62
  63                 g_free(entry->server);
  64                 g_free(entry->domain);
  65                 g_free(entry->interface);
  66                 g_free(entry);
  67         }
  68
  69         g_slist_free(entries);
  70 }
  71
  72 static gint compare_priority(gconstpointer a, gconstpointer b)
  73 {
  74         const struct connman_resolver *resolver1 = a;
  75         const struct connman_resolver *resolver2 = b;
  76
  77         return resolver2->priority - resolver1->priority;
  78 }
  79
  80 /**
  81  * connman_resolver_register:
  82  * @resolver: resolver module
  83  *
  84  * Register a new resolver module
  85  *
  86  * Returns: %0 on success
  87  */
  88 int connman_resolver_register(struct connman_resolver *resolver)
  89 {
  90         GSList *list;
  91
  92         DBG("resolver %p name %s", resolver, resolver->name);
  93
  94         resolver_list = g_slist_insert_sorted(resolver_list, resolver,
  95                                                         compare_priority);
  96
  97         if (resolver->append == NULL)
  98                 return 0;
  99
 100         for (list = entry_list; list; list = list->next) {
 101                 struct entry_data *entry = list->data;
 102
 103                 if (entry->resolver)
 104                         continue;
 105
 106                 if (resolver->append(entry->interface, entry->domain,
 107                                                         entry->server) == 0)
 108                         entry->resolver = resolver;
 109         }
 110
 111         return 0;
 112 }
 113
 114 /**
 115  * connman_resolver_unregister:
 116  * @resolver: resolver module
 117  *
 118  * Remove a previously registered resolver module
 119  */
 120 void connman_resolver_unregister(struct connman_resolver *resolver)
 121 {
 122         GSList *list, *matches = NULL;
 123
 124         DBG("resolver %p name %s", resolver, resolver->name);
 125
 126         resolver_list = g_slist_remove(resolver_list, resolver);
 127
 128         for (list = entry_list; list; list = list->next) {
 129                 struct entry_data *entry = list->data;
 130
 131                 if (entry->resolver != resolver)
 132                         continue;
 133
 134                 matches = g_slist_append(matches, entry);
 135         }
 136
 137         remove_entries(matches);
 138 }
 139
 140 static int append_resolver(const char *interface, const char *domain,
 141                                         const char *server, unsigned int flags)
 142 {
 143         struct entry_data *entry;
 144         GSList *list;
 145
 146         DBG("interface %s domain %s server %s flags %d",
 147                                         interface, domain, server, flags);
 148
 149         if (server == NULL)
 150                 return -EINVAL;
 151
 152         entry = g_try_new0(struct entry_data, 1);
 153         if (entry == NULL)
 154                 return -ENOMEM;
 155
 156         entry->interface = g_strdup(interface);
 157         entry->domain = g_strdup(domain);
 158         entry->server = g_strdup(server);
 159         entry->flags = flags;
 160
 161         entry_list = g_slist_append(entry_list, entry);
 162
 163         for (list = resolver_list; list; list = list->next) {
 164                 struct connman_resolver *resolver = list->data;
 165
 166                 if (resolver->append == NULL)
 167                         continue;
 168
 169                 if (resolver->append(interface, domain, server) == 0) {
 170                         entry->resolver = resolver;
 171                         break;
 172                 }
 173         }
 174
 175         return 0;
 176 }
 177
 178 /**
 179  * connman_resolver_append:
 180  * @interface: network interface
 181  * @domain: domain limitation
 182  * @server: server address
 183  *
 184  * Append resolver server address to current list
 185  */
 186 int connman_resolver_append(const char *interface, const char *domain,
 187                                                         const char *server)
 188 {
 189         DBG("interface %s domain %s server %s", interface, domain, server);
 190
 191         return append_resolver(interface, domain, server, 0);
 192 }
 193
 194 /**
 195  * connman_resolver_remove:
 196  * @interface: network interface
 197  * @domain: domain limitation
 198  * @server: server address
 199  *
 200  * Remover resolver server address from current list
 201  */
 202 int connman_resolver_remove(const char *interface, const char *domain,
 203                                                         const char *server)
 204 {
 205         GSList *list, *matches = NULL;
 206
 207         DBG("interface %s domain %s server %s", interface, domain, server);
 208
 209         if (server == NULL)
 210                 return -EINVAL;
 211
 212         for (list = entry_list; list; list = list->next) {
 213                 struct entry_data *entry = list->data;
 214
 215                 if (interface != NULL &&
 216                                 g_strcmp0(entry->interface, interface) != 0)
 217                         continue;
 218
 219                 if (domain != NULL && g_strcmp0(entry->domain, domain) != 0)
 220                         continue;
 221
 222                 if (g_strcmp0(entry->server, server) != 0)
 223                         continue;
 224
 225                 matches = g_slist_append(matches, entry);
 226         }
 227
 228         if (matches == NULL)
 229                 return -ENOENT;
 230
 231         remove_entries(matches);
 232
 233         return 0;
 234 }
 235
 236 /**
 237  * connman_resolver_remove_all:
 238  * @interface: network interface
 239  *
 240  * Remove all resolver server address for the specified interface
 241  */
 242 int connman_resolver_remove_all(const char *interface)
 243 {
 244         GSList *list, *matches = NULL;
 245
 246         DBG("interface %s", interface);
 247
 248         if (interface == NULL)
 249                 return -EINVAL;
 250
 251         for (list = entry_list; list; list = list->next) {
 252                 struct entry_data *entry = list->data;
 253
 254                 if (g_strcmp0(entry->interface, interface) != 0)
 255                         continue;
 256
 257                 matches = g_slist_append(matches, entry);
 258         }
 259
 260         if (matches == NULL)
 261                 return -ENOENT;
 262
 263         remove_entries(matches);
 264
 265         return 0;
 266 }
 267
 268 /**
 269  * connman_resolver_append_public_server:
 270  * @server: server address
 271  *
 272  * Append public resolver server address to current list
 273  */
 274 int connman_resolver_append_public_server(const char *server)
 275 {
 276         DBG("server %s", server);
 277
 278         return append_resolver(NULL, NULL, server, RESOLVER_FLAG_PUBLIC);
 279 }
 280
 281 /**
 282  * connman_resolver_remove_public_server:
 283  * @server: server address
 284  *
 285  * Remove public resolver server address to current list
 286  */
 287 int connman_resolver_remove_public_server(const char *server)
 288 {
 289         DBG("server %s", server);
 290
 291         return connman_resolver_remove(NULL, NULL, server);
 292 }
 293
 294 /**
 295  * connman_resolver_flush:
 296  *
 297  * Flush pending resolver requests
 298  */
 299 void connman_resolver_flush(void)
 300 {
 301         GSList *list;
 302
 303         for (list = resolver_list; list; list = list->next) {
 304                 struct connman_resolver *resolver = list->data;
 305
 306                 if (resolver->flush == NULL)
 307                         continue;
 308
 309                 resolver->flush();
 310         }
 311
 312         return;
 313 }
 314
 315 static int selftest_append(const char *interface, const char *domain,
 316                                                         const char *server)
 317 {
 318         DBG("server %s", server);
 319
 320         return 0;
 321 }
 322
 323 static int selftest_remove(const char *interface, const char *domain,
 324                                                         const char *server)
 325 {
 326         DBG("server %s", server);
 327
 328         return 0;
 329 }
 330
 331 static struct connman_resolver selftest_resolver = {
 332         .name     = "selftest",
 333         .priority = CONNMAN_RESOLVER_PRIORITY_HIGH + 42,
 334         .append   = selftest_append,
 335         .remove   = selftest_remove,
 336 };
 337
 338 int __connman_resolver_selftest(void)
 339 {
 340         connman_resolver_append("wlan0", "lwn.net", "192.168.0.1");
 341
 342         connman_resolver_register(&selftest_resolver);
 343
 344         connman_resolver_append("eth0", "connman.net", "192.168.42.1");
 345         connman_resolver_append("wlan0", "lwn.net", "192.168.0.2");
 346
 347         connman_resolver_append_public_server("8.8.8.8");
 348
 349         connman_resolver_remove_public_server("8.8.8.8");
 350
 351         connman_resolver_remove_all("wlan0");
 352
 353         connman_resolver_unregister(&selftest_resolver);
 354
 355         return 0;
 356 }
 357
 358 struct resolvfile_entry {
 359         char *interface;
 360         char *domain;
 361         char *server;
 362 };
 363
 364 static GList *resolvfile_list = NULL;
 365
 366 static void resolvfile_remove_entries(GList *entries)
 367 {
 368         GList *list;
 369
 370         for (list = entries; list; list = list->next) {
 371                 struct resolvfile_entry *entry = list->data;
 372
 373                 resolvfile_list = g_list_remove(resolvfile_list, entry);
 374
 375                 g_free(entry->server);
 376                 g_free(entry->domain);
 377                 g_free(entry->interface);
 378                 g_free(entry);
 379         }
 380
 381         g_list_free(entries);
 382 }
 383
 384 static int resolvfile_export(void)
 385 {
 386         GList *list;
 387         GString *content;
 388         int fd, err;
 389         unsigned int count;
 390         mode_t old_umask;
 391
 392         content = g_string_new("# Generated by Connection Manager\n");
 393
 394         /*
 395          * Nameservers are added in reverse so that the most recently
 396          * appended entry is the primary nameserver. No more than MAXNS
 397          * nameservers are used.
 398          */
 399         for (count = 0, list = g_list_last(resolvfile_list);
 400                                                 list && (count < MAXNS);
 401                                                 list = g_list_previous(list)) {
 402                 struct resolvfile_entry *entry = list->data;
 403                 g_string_append_printf(content, "nameserver %s\n",
 404                                                                 entry->server);
 405                 count++;
 406         }
 407
 408         old_umask = umask(022);
 409
 410         fd = open("/etc/resolv.conf", O_RDWR | O_CREAT,
 411                                         S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 412         if (fd < 0) {
 413                 err = -errno;
 414                 goto done;
 415         }
 416
 417         if (ftruncate(fd, 0) < 0) {
 418                 err = -errno;
 419                 goto failed;
 420         }
 421
 422         err = 0;
 423
 424         if (write(fd, content->str, content->len) < 0)
 425                 err = -errno;
 426
 427 failed:
 428         close(fd);
 429
 430 done:
 431         g_string_free(content, TRUE);
 432         umask(old_umask);
 433
 434         return err;
 435 }
 436
 437 static int resolvfile_append(const char *interface, const char *domain,
 438                                                         const char *server)
 439 {
 440         struct resolvfile_entry *entry;
 441
 442         DBG("interface %s server %s", interface, server);
 443
 444         if (interface == NULL)
 445                 return -ENOENT;
 446
 447         entry = g_try_new0(struct resolvfile_entry, 1);
 448         if (entry == NULL)
 449                 return -ENOMEM;
 450
 451         entry->interface = g_strdup(interface);
 452         entry->domain = g_strdup(domain);
 453         entry->server = g_strdup(server);
 454
 455         resolvfile_list = g_list_append(resolvfile_list, entry);
 456
 457         return resolvfile_export();
 458 }
 459
 460 static int resolvfile_remove(const char *interface, const char *domain,
 461                                                         const char *server)
 462 {
 463         GList *list, *matches = NULL;
 464
 465         DBG("interface %s server %s", interface, server);
 466
 467         for (list = resolvfile_list; list; list = g_list_next(list)) {
 468                 struct resolvfile_entry *entry = list->data;
 469
 470                 if (interface != NULL &&
 471                                 g_strcmp0(entry->interface, interface) != 0)
 472                         continue;
 473
 474                 if (domain != NULL && g_strcmp0(entry->domain, domain) != 0)
 475                         continue;
 476
 477                 if (g_strcmp0(entry->server, server) != 0)
 478                         continue;
 479
 480                 matches = g_list_append(matches, entry);
 481         }
 482
 483         resolvfile_remove_entries(matches);
 484
 485         return resolvfile_export();
 486 }
 487
 488 static struct connman_resolver resolvfile_resolver = {
 489         .name           = "resolvfile",
 490         .priority       = CONNMAN_RESOLVER_PRIORITY_LOW,
 491         .append         = resolvfile_append,
 492         .remove         = resolvfile_remove,
 493 };
 494
 495 int __connman_resolver_init(void)
 496 {
 497         DBG("");
 498
 499         return connman_resolver_register(&resolvfile_resolver);
 500 }
 501
 502 void __connman_resolver_cleanup(void)
 503 {
 504         DBG("");
 505
 506         connman_resolver_unregister(&resolvfile_resolver);
 507 }