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 #define _GNU_SOURCE
  27 #include <stdio.h>
  28 #include <errno.h>
  29 #include <fcntl.h>
  30 #include <unistd.h>
  31 #include <string.h>
  32 #include <sys/stat.h>
  33 #include <resolv.h>
  34
  35 #include "connman.h"
  36
  37 #define RESOLVER_FLAG_PUBLIC (1 << 0)
  38
  39 struct entry_data {
  40         char *interface;
  41         char *domain;
  42         char *server;
  43         unsigned int flags;
  44         guint timeout;
  45 };
  46
  47 static GSList *entry_list = NULL;
  48 static connman_bool_t dnsproxy_enabled = FALSE;
  49
  50 struct resolvfile_entry {
  51         char *interface;
  52         char *domain;
  53         char *server;
  54 };
  55
  56 static GList *resolvfile_list = NULL;
  57
  58 static void resolvfile_remove_entries(GList *entries)
  59 {
  60         GList *list;
  61
  62         for (list = entries; list; list = list->next) {
  63                 struct resolvfile_entry *entry = list->data;
  64
  65                 resolvfile_list = g_list_remove(resolvfile_list, entry);
  66
  67                 g_free(entry->server);
  68                 g_free(entry->domain);
  69                 g_free(entry->interface);
  70                 g_free(entry);
  71         }
  72
  73         g_list_free(entries);
  74 }
  75
  76 static int resolvfile_export(void)
  77 {
  78         GList *list;
  79         GString *content;
  80         int fd, err;
  81         unsigned int count;
  82         mode_t old_umask;
  83
  84         content = g_string_new("# Generated by Connection Manager\n");
  85
  86         /*
  87          * Domains and nameservers are added in reverse so that the most
  88          * recently appended entry is the primary one. No more than
  89          * MAXDNSRCH/MAXNS entries are used.
  90          */
  91
  92         for (count = 0, list = g_list_last(resolvfile_list);
  93                                                 list && (count < MAXDNSRCH);
  94                                                 list = g_list_previous(list)) {
  95                 struct resolvfile_entry *entry = list->data;
  96
  97                 if (!entry->domain)
  98                         continue;
  99
 100                 if (count == 0)
 101                         g_string_append_printf(content, "search ");
 102
 103                 g_string_append_printf(content, "%s ", entry->domain);
 104                 count++;
 105         }
 106
 107         if (count)
 108                 g_string_append_printf(content, "\n");
 109
 110         for (count = 0, list = g_list_last(resolvfile_list);
 111                                                 list && (count < MAXNS);
 112                                                 list = g_list_previous(list)) {
 113                 struct resolvfile_entry *entry = list->data;
 114
 115                 if (!entry->server)
 116                         continue;
 117
 118                 g_string_append_printf(content, "nameserver %s\n",
 119                                                                 entry->server);
 120                 count++;
 121         }
 122
 123         old_umask = umask(022);
 124
 125         fd = open("/etc/resolv.conf", O_RDWR | O_CREAT | O_CLOEXEC,
 126                                         S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 127         if (fd < 0) {
 128                 err = -errno;
 129                 goto done;
 130         }
 131
 132         if (ftruncate(fd, 0) < 0) {
 133                 err = -errno;
 134                 goto failed;
 135         }
 136
 137         err = 0;
 138
 139         if (write(fd, content->str, content->len) < 0)
 140                 err = -errno;
 141
 142 failed:
 143         close(fd);
 144
 145 done:
 146         g_string_free(content, TRUE);
 147         umask(old_umask);
 148
 149         return err;
 150 }
 151
 152 int __connman_resolvfile_append(const char *interface, const char *domain,
 153                                                         const char *server)
 154 {
 155         struct resolvfile_entry *entry;
 156
 157         DBG("interface %s server %s", interface, server);
 158
 159         if (interface == NULL)
 160                 return -ENOENT;
 161
 162         entry = g_try_new0(struct resolvfile_entry, 1);
 163         if (entry == NULL)
 164                 return -ENOMEM;
 165
 166         entry->interface = g_strdup(interface);
 167         entry->domain = g_strdup(domain);
 168         entry->server = g_strdup(server);
 169
 170         resolvfile_list = g_list_append(resolvfile_list, entry);
 171
 172         return resolvfile_export();
 173 }
 174
 175 int __connman_resolvfile_remove(const char *interface, const char *domain,
 176                                                         const char *server)
 177 {
 178         GList *list, *matches = NULL;
 179
 180         DBG("interface %s server %s", interface, server);
 181
 182         for (list = resolvfile_list; list; list = g_list_next(list)) {
 183                 struct resolvfile_entry *entry = list->data;
 184
 185                 if (interface != NULL &&
 186                                 g_strcmp0(entry->interface, interface) != 0)
 187                         continue;
 188
 189                 if (domain != NULL && g_strcmp0(entry->domain, domain) != 0)
 190                         continue;
 191
 192                 if (g_strcmp0(entry->server, server) != 0)
 193                         continue;
 194
 195                 matches = g_list_append(matches, entry);
 196         }
 197
 198         resolvfile_remove_entries(matches);
 199
 200         return resolvfile_export();
 201 }
 202
 203 static void remove_entries(GSList *entries)
 204 {
 205         GSList *list;
 206
 207         for (list = entries; list; list = list->next) {
 208                 struct entry_data *entry = list->data;
 209
 210                 entry_list = g_slist_remove(entry_list, entry);
 211
 212                 if (dnsproxy_enabled == TRUE) {
 213                         __connman_dnsproxy_remove(entry->interface, entry->domain,
 214                                                         entry->server);
 215                 } else {
 216                         __connman_resolvfile_remove(entry->interface, entry->domain,
 217                                                         entry->server);
 218                 }
 219
 220                 if (entry->timeout)
 221                         g_source_remove(entry->timeout);
 222                 g_free(entry->server);
 223                 g_free(entry->domain);
 224                 g_free(entry->interface);
 225                 g_free(entry);
 226         }
 227
 228         g_slist_free(entries);
 229 }
 230
 231 static gboolean resolver_expire_cb(gpointer user_data)
 232 {
 233         struct entry_data *entry = user_data;
 234         GSList *list;
 235
 236         DBG("interface %s domain %s server %s",
 237                         entry->interface, entry->domain, entry->server);
 238
 239         list = g_slist_append(NULL, entry);
 240         remove_entries(list);
 241
 242         return FALSE;
 243 }
 244
 245 static int append_resolver(const char *interface, const char *domain,
 246                                 const char *server, unsigned int lifetime,
 247                                                         unsigned int flags)
 248 {
 249         struct entry_data *entry;
 250
 251         DBG("interface %s domain %s server %s lifetime %d flags %d",
 252                                 interface, domain, server, lifetime, flags);
 253
 254         if (server == NULL && domain == NULL)
 255                 return -EINVAL;
 256
 257         entry = g_try_new0(struct entry_data, 1);
 258         if (entry == NULL)
 259                 return -ENOMEM;
 260
 261         entry->interface = g_strdup(interface);
 262         entry->domain = g_strdup(domain);
 263         entry->server = g_strdup(server);
 264         entry->flags = flags;
 265         if (lifetime)
 266                 entry->timeout = g_timeout_add_seconds(lifetime,
 267                                                 resolver_expire_cb, 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, entry);
 327                 return 0;
 328         }
 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 }