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         char *interface;
  40         char *domain;
  41         char *server;
  42         unsigned int flags;
  43         guint timeout;
  44 };
  45
  46 static GSList *entry_list = NULL;
  47 static connman_bool_t dnsproxy_enabled = FALSE;
  48
  49 struct resolvfile_entry {
  50         char *interface;
  51         char *domain;
  52         char *server;
  53 };
  54
  55 static GList *resolvfile_list = NULL;
  56
  57 static void resolvfile_remove_entries(GList *entries)
  58 {
  59         GList *list;
  60
  61         for (list = entries; list; list = list->next) {
  62                 struct resolvfile_entry *entry = list->data;
  63
  64                 resolvfile_list = g_list_remove(resolvfile_list, entry);
  65
  66                 g_free(entry->server);
  67                 g_free(entry->domain);
  68                 g_free(entry->interface);
  69                 g_free(entry);
  70         }
  71
  72         g_list_free(entries);
  73 }
  74
  75 static int resolvfile_export(void)
  76 {
  77         GList *list;
  78         GString *content;
  79         int fd, err;
  80         unsigned int count;
  81         mode_t old_umask;
  82
  83         content = g_string_new("# Generated by Connection Manager\n");
  84
  85         /*
  86          * Domains and nameservers are added in reverse so that the most
  87          * recently appended entry is the primary one. No more than
  88          * MAXDNSRCH/MAXNS entries are used.
  89          */
  90
  91         for (count = 0, list = g_list_last(resolvfile_list);
  92                                                 list && (count < MAXDNSRCH);
  93                                                 list = g_list_previous(list)) {
  94                 struct resolvfile_entry *entry = list->data;
  95
  96                 if (!entry->domain)
  97                         continue;
  98
  99                 if (count == 0)
 100                         g_string_append_printf(content, "search ");
 101
 102                 g_string_append_printf(content, "%s ", entry->domain);
 103                 count++;
 104         }
 105
 106         if (count)
 107                 g_string_append_printf(content, "\n");
 108
 109         for (count = 0, list = g_list_last(resolvfile_list);
 110                                                 list && (count < MAXNS);
 111                                                 list = g_list_previous(list)) {
 112                 struct resolvfile_entry *entry = list->data;
 113
 114                 if (!entry->server)
 115                         continue;
 116
 117                 g_string_append_printf(content, "nameserver %s\n",
 118                                                                 entry->server);
 119                 count++;
 120         }
 121
 122         old_umask = umask(022);
 123
 124         fd = open("/etc/resolv.conf", O_RDWR | O_CREAT,
 125                                         S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 126         if (fd < 0) {
 127                 err = -errno;
 128                 goto done;
 129         }
 130
 131         if (ftruncate(fd, 0) < 0) {
 132                 err = -errno;
 133                 goto failed;
 134         }
 135
 136         err = 0;
 137
 138         if (write(fd, content->str, content->len) < 0)
 139                 err = -errno;
 140
 141 failed:
 142         close(fd);
 143
 144 done:
 145         g_string_free(content, TRUE);
 146         umask(old_umask);
 147
 148         return err;
 149 }
 150
 151 int __connman_resolvfile_append(const char *interface, const char *domain,
 152                                                         const char *server)
 153 {
 154         struct resolvfile_entry *entry;
 155
 156         DBG("interface %s server %s", interface, server);
 157
 158         if (interface == NULL)
 159                 return -ENOENT;
 160
 161         entry = g_try_new0(struct resolvfile_entry, 1);
 162         if (entry == NULL)
 163                 return -ENOMEM;
 164
 165         entry->interface = g_strdup(interface);
 166         entry->domain = g_strdup(domain);
 167         entry->server = g_strdup(server);
 168
 169         resolvfile_list = g_list_append(resolvfile_list, entry);
 170
 171         return resolvfile_export();
 172 }
 173
 174 int __connman_resolvfile_remove(const char *interface, const char *domain,
 175                                                         const char *server)
 176 {
 177         GList *list, *matches = NULL;
 178
 179         DBG("interface %s server %s", interface, server);
 180
 181         for (list = resolvfile_list; list; list = g_list_next(list)) {
 182                 struct resolvfile_entry *entry = list->data;
 183
 184                 if (interface != NULL &&
 185                                 g_strcmp0(entry->interface, interface) != 0)
 186                         continue;
 187
 188                 if (domain != NULL && g_strcmp0(entry->domain, domain) != 0)
 189                         continue;
 190
 191                 if (g_strcmp0(entry->server, server) != 0)
 192                         continue;
 193
 194                 matches = g_list_append(matches, entry);
 195         }
 196
 197         resolvfile_remove_entries(matches);
 198
 199         return resolvfile_export();
 200 }
 201
 202 static void remove_entries(GSList *entries)
 203 {
 204         GSList *list;
 205
 206         for (list = entries; list; list = list->next) {
 207                 struct entry_data *entry = list->data;
 208
 209                 entry_list = g_slist_remove(entry_list, entry);
 210
 211                 if (dnsproxy_enabled == TRUE) {
 212                         __connman_dnsproxy_remove(entry->interface, entry->domain,
 213                                                         entry->server);
 214                 } else {
 215                         __connman_resolvfile_remove(entry->interface, entry->domain,
 216                                                         entry->server);
 217                 }
 218
 219                 if (entry->timeout)
 220                         g_source_remove(entry->timeout);
 221                 g_free(entry->server);
 222                 g_free(entry->domain);
 223                 g_free(entry->interface);
 224                 g_free(entry);
 225         }
 226
 227         g_slist_free(entries);
 228 }
 229
 230 static gboolean resolver_expire_cb(gpointer user_data)
 231 {
 232         struct entry_data *entry = user_data;
 233         GSList *list;
 234
 235         DBG("interface %s domain %s server %s",
 236             entry->interface, entry->domain, entry->server);
 237
 238         list = g_slist_append(NULL, entry);
 239         remove_entries(list);
 240
 241         return FALSE;
 242 }
 243
 244 static int append_resolver(const char *interface, const char *domain,
 245                            const char *server, unsigned int lifetime,
 246                            unsigned int flags)
 247 {
 248         struct entry_data *entry;
 249
 250         DBG("interface %s domain %s server %s lifetime %d flags %d",
 251             interface, domain, server, lifetime, flags);
 252
 253         if (server == NULL && domain == NULL)
 254                 return -EINVAL;
 255
 256         entry = g_try_new0(struct entry_data, 1);
 257         if (entry == NULL)
 258                 return -ENOMEM;
 259
 260         entry->interface = g_strdup(interface);
 261         entry->domain = g_strdup(domain);
 262         entry->server = g_strdup(server);
 263         entry->flags = flags;
 264         if (lifetime)
 265                 entry->timeout = g_timeout_add_seconds(lifetime,
 266                                                        resolver_expire_cb,
 267                                                        entry);
 268
 269         entry_list = g_slist_append(entry_list, entry);
 270
 271         if (dnsproxy_enabled == TRUE)
 272                 __connman_dnsproxy_append(interface, domain, server);
 273         else
 274                 __connman_resolvfile_append(interface, domain, server);
 275
 276         return 0;
 277 }
 278
 279 /**
 280  * connman_resolver_append:
 281  * @interface: network interface
 282  * @domain: domain limitation
 283  * @server: server address
 284  *
 285  * Append resolver server address to current list
 286  */
 287 int connman_resolver_append(const char *interface, const char *domain,
 288                                                 const char *server)
 289 {
 290         DBG("interface %s domain %s server %s", interface, domain, server);
 291
 292         return append_resolver(interface, domain, server, 0, 0);
 293 }
 294
 295 /**
 296  * connman_resolver_append_lifetime:
 297  * @interface: network interface
 298  * @domain: domain limitation
 299  * @server: server address
 300  * @timeout: server lifetime in seconds
 301  *
 302  * Append resolver server address to current list
 303  */
 304 int connman_resolver_append_lifetime(const char *interface, const char *domain,
 305                                      const char *server, unsigned int lifetime)
 306 {
 307         GSList *list;
 308
 309         DBG("interface %s domain %s server %s lifetime %d",
 310             interface, domain, server, lifetime);
 311
 312         if (server == NULL)
 313                 return -EINVAL;
 314
 315         for (list = entry_list; list; list = list->next) {
 316                 struct entry_data *entry = list->data;
 317
 318                 if (!entry->timeout ||
 319                     g_strcmp0(entry->interface, interface) ||
 320                     g_strcmp0(entry->domain, domain) ||
 321                     g_strcmp0(entry->server, server))
 322                         continue;
 323
 324                 g_source_remove(entry->timeout);
 325                 entry->timeout = g_timeout_add_seconds(lifetime,
 326                                                        resolver_expire_cb,
 327                                                        entry);
 328                 return 0;
 329         }
 330         return append_resolver(interface, domain, server, lifetime, 0);
 331 }
 332
 333 /**
 334  * connman_resolver_remove:
 335  * @interface: network interface
 336  * @domain: domain limitation
 337  * @server: server address
 338  *
 339  * Remover resolver server address from current list
 340  */
 341 int connman_resolver_remove(const char *interface, const char *domain,
 342                                                         const char *server)
 343 {
 344         GSList *list, *matches = NULL;
 345
 346         DBG("interface %s domain %s server %s", interface, domain, server);
 347
 348         if (server == NULL)
 349                 return -EINVAL;
 350
 351         for (list = entry_list; list; list = list->next) {
 352                 struct entry_data *entry = list->data;
 353
 354                 if (interface != NULL &&
 355                                 g_strcmp0(entry->interface, interface) != 0)
 356                         continue;
 357
 358                 if (domain != NULL && g_strcmp0(entry->domain, domain) != 0)
 359                         continue;
 360
 361                 if (g_strcmp0(entry->server, server) != 0)
 362                         continue;
 363
 364                 matches = g_slist_append(matches, entry);
 365         }
 366
 367         if (matches == NULL)
 368                 return -ENOENT;
 369
 370         remove_entries(matches);
 371
 372         return 0;
 373 }
 374
 375 /**
 376  * connman_resolver_remove_all:
 377  * @interface: network interface
 378  *
 379  * Remove all resolver server address for the specified interface
 380  */
 381 int connman_resolver_remove_all(const char *interface)
 382 {
 383         GSList *list, *matches = NULL;
 384
 385         DBG("interface %s", interface);
 386
 387         if (interface == NULL)
 388                 return -EINVAL;
 389
 390         for (list = entry_list; list; list = list->next) {
 391                 struct entry_data *entry = list->data;
 392
 393                 if (g_strcmp0(entry->interface, interface) != 0)
 394                         continue;
 395
 396                 matches = g_slist_append(matches, entry);
 397         }
 398
 399         if (matches == NULL)
 400                 return -ENOENT;
 401
 402         remove_entries(matches);
 403
 404         return 0;
 405 }
 406
 407 /**
 408  * connman_resolver_append_public_server:
 409  * @server: server address
 410  *
 411  * Append public resolver server address to current list
 412  */
 413 int connman_resolver_append_public_server(const char *server)
 414 {
 415         DBG("server %s", server);
 416
 417         return append_resolver(NULL, NULL, server, 0, RESOLVER_FLAG_PUBLIC);
 418 }
 419
 420 /**
 421  * connman_resolver_remove_public_server:
 422  * @server: server address
 423  *
 424  * Remove public resolver server address to current list
 425  */
 426 int connman_resolver_remove_public_server(const char *server)
 427 {
 428         DBG("server %s", server);
 429
 430         return connman_resolver_remove(NULL, NULL, server);
 431 }
 432
 433 /**
 434  * connman_resolver_flush:
 435  *
 436  * Flush pending resolver requests
 437  */
 438 void connman_resolver_flush(void)
 439 {
 440         if (dnsproxy_enabled == TRUE)
 441                 __connman_dnsproxy_flush();
 442
 443         return;
 444 }
 445
 446 int __connman_resolver_init(connman_bool_t dnsproxy)
 447 {
 448         DBG("dnsproxy %d", dnsproxy);
 449
 450         if (dnsproxy == FALSE)
 451                 return 0;
 452
 453         if (__connman_dnsproxy_init() < 0) {
 454                 /* Fall back to resolv.conf */
 455                 return 0;
 456         }
 457
 458         dnsproxy_enabled = TRUE;
 459
 460         return 0;
 461 }
 462
 463 void __connman_resolver_cleanup(void)
 464 {
 465         DBG("");
 466
 467         if (dnsproxy_enabled == TRUE)
 468                 __connman_dnsproxy_cleanup();
 469 }