src/tethering.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 <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <unistd.h>
  29 #include <stdio.h>
  30 #include <sys/ioctl.h>
  31 #include <net/if.h>
  32 #include <linux/sockios.h>
  33
  34 #include "connman.h"
  35
  36 #include <gdhcp/gdhcp.h>
  37
  38 #include <gdbus.h>
  39
  40 #define BRIDGE_PROC_DIR "/proc/sys/net/bridge"
  41
  42 #define BRIDGE_NAME "tether"
  43 #define BRIDGE_IP "192.168.218.1"
  44 #define BRIDGE_BCAST "192.168.218.255"
  45 #define BRIDGE_SUBNET "255.255.255.0"
  46 #define BRIDGE_IP_START "192.168.218.100"
  47 #define BRIDGE_IP_END "192.168.218.200"
  48 #define BRIDGE_DNS "8.8.8.8"
  49
  50 static char *default_interface = NULL;
  51 static volatile gint tethering_enabled;
  52 static GDHCPServer *tethering_dhcp_server = NULL;
  53 static DBusConnection *connection;
  54 static GHashTable *pn_hash;
  55
  56 struct connman_private_network {
  57         char *owner;
  58         guint watch;
  59 };
  60
  61 const char *__connman_tethering_get_bridge(void)
  62 {
  63         struct stat st;
  64
  65         if (stat(BRIDGE_PROC_DIR, &st) < 0) {
  66                 connman_error("Missing support for 802.1d ethernet bridging");
  67                 return NULL;
  68         }
  69
  70         return BRIDGE_NAME;
  71 }
  72
  73 static void dhcp_server_debug(const char *str, void *data)
  74 {
  75         connman_info("%s: %s\n", (const char *) data, str);
  76 }
  77
  78 static void dhcp_server_error(GDHCPServerError error)
  79 {
  80         switch (error) {
  81         case G_DHCP_SERVER_ERROR_NONE:
  82                 connman_error("OK");
  83                 break;
  84         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
  85                 connman_error("Interface unavailable");
  86                 break;
  87         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
  88                 connman_error("Interface in use");
  89                 break;
  90         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
  91                 connman_error("Interface down");
  92                 break;
  93         case G_DHCP_SERVER_ERROR_NOMEM:
  94                 connman_error("No memory");
  95                 break;
  96         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
  97                 connman_error("Invalid index");
  98                 break;
  99         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 100                 connman_error("Invalid option");
 101                 break;
 102         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 103                 connman_error("Invalid address");
 104                 break;
 105         }
 106 }
 107
 108 static GDHCPServer *dhcp_server_start(const char *bridge,
 109                                 const char *router, const char* subnet,
 110                                 const char *start_ip, const char *end_ip,
 111                                 unsigned int lease_time, const char *dns)
 112 {
 113         GDHCPServerError error;
 114         GDHCPServer *dhcp_server;
 115         int index;
 116
 117         DBG("");
 118
 119         index = connman_inet_ifindex(bridge);
 120         if (index < 0)
 121                 return NULL;
 122
 123         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 124         if (dhcp_server == NULL) {
 125                 dhcp_server_error(error);
 126                 return NULL;
 127         }
 128
 129         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 130
 131         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 132         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 133         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 134         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 135         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 136
 137         g_dhcp_server_start(dhcp_server);
 138
 139         return dhcp_server;
 140 }
 141
 142 static void dhcp_server_stop(GDHCPServer *server)
 143 {
 144         if (server == NULL)
 145                 return;
 146
 147         g_dhcp_server_unref(server);
 148 }
 149
 150 static int set_forward_delay(const char *name, unsigned int delay)
 151 {
 152         FILE *f;
 153         char *forward_delay_path;
 154
 155         forward_delay_path =
 156                 g_strdup_printf("/sys/class/net/%s/bridge/forward_delay", name);
 157
 158         if (forward_delay_path == NULL)
 159                 return -ENOMEM;
 160
 161         f = fopen(forward_delay_path, "r+");
 162
 163         g_free(forward_delay_path);
 164
 165         if (f == NULL)
 166                 return -errno;
 167
 168         fprintf(f, "%d", delay);
 169
 170         fclose(f);
 171
 172         return 0;
 173 }
 174
 175 static int create_bridge(const char *name)
 176 {
 177         int sk, err;
 178
 179         DBG("name %s", name);
 180
 181         sk = socket(AF_INET, SOCK_STREAM, 0);
 182         if (sk < 0)
 183                 return -EOPNOTSUPP;
 184
 185         err = ioctl(sk, SIOCBRADDBR, name);
 186
 187         if (err < 0)
 188                 return -EOPNOTSUPP;
 189
 190         err = set_forward_delay(name, 0);
 191
 192         if (err < 0)
 193                 ioctl(sk, SIOCBRDELBR, name);
 194
 195         close(sk);
 196
 197         return err;
 198 }
 199
 200 static int remove_bridge(const char *name)
 201 {
 202         int sk, err;
 203
 204         DBG("name %s", name);
 205
 206         sk = socket(AF_INET, SOCK_STREAM, 0);
 207         if (sk < 0)
 208                 return -EOPNOTSUPP;
 209
 210         err = ioctl(sk, SIOCBRDELBR, name);
 211
 212         close(sk);
 213
 214         if (err < 0)
 215                 return -EOPNOTSUPP;
 216
 217         return 0;
 218 }
 219
 220 static int enable_bridge(const char *name)
 221 {
 222         int err, index;
 223
 224         index = connman_inet_ifindex(name);
 225         if (index < 0)
 226                 return index;
 227
 228         err = __connman_inet_modify_address(RTM_NEWADDR,
 229                         NLM_F_REPLACE | NLM_F_ACK, index, AF_INET,
 230                                         BRIDGE_IP, NULL, 24, BRIDGE_BCAST);
 231         if (err < 0)
 232                 return err;
 233
 234         return connman_inet_ifup(index);
 235 }
 236
 237 static int disable_bridge(const char *name)
 238 {
 239         int index;
 240
 241         index = connman_inet_ifindex(name);
 242         if (index < 0)
 243                 return index;
 244
 245         return connman_inet_ifdown(index);
 246 }
 247
 248 static int enable_ip_forward(connman_bool_t enable)
 249 {
 250
 251         FILE *f;
 252
 253         f = fopen("/proc/sys/net/ipv4/ip_forward", "r+");
 254         if (f == NULL)
 255                 return -errno;
 256
 257         if (enable == TRUE)
 258                 fprintf(f, "1");
 259         else
 260                 fprintf(f, "0");
 261
 262         fclose(f);
 263
 264         return 0;
 265 }
 266
 267 static int enable_nat(const char *interface)
 268 {
 269         int err;
 270
 271         if (interface == NULL)
 272                 return 0;
 273
 274         /* Enable IPv4 forwarding */
 275         err = enable_ip_forward(TRUE);
 276         if (err < 0)
 277                 return err;
 278
 279         /* POSTROUTING flush */
 280         err = __connman_iptables_command("-t nat -F POSTROUTING");
 281         if (err < 0)
 282                 return err;
 283
 284         /* Enable masquerading */
 285         err = __connman_iptables_command("-t nat -A POSTROUTING "
 286                                         "-o %s -j MASQUERADE", interface);
 287         if (err < 0)
 288                 return err;
 289
 290         return __connman_iptables_commit("nat");
 291 }
 292
 293 static void disable_nat(const char *interface)
 294 {
 295         int err;
 296
 297         /* Disable IPv4 forwarding */
 298         enable_ip_forward(FALSE);
 299
 300         /* POSTROUTING flush */
 301         err = __connman_iptables_command("-t nat -F POSTROUTING");
 302         if (err < 0)
 303                 return;
 304
 305         __connman_iptables_commit("nat");
 306 }
 307
 308 void __connman_tethering_set_enabled(void)
 309 {
 310         int err;
 311
 312         DBG("enabled %d", tethering_enabled + 1);
 313
 314         if (g_atomic_int_exchange_and_add(&tethering_enabled, 1) == 0) {
 315                 err = create_bridge(BRIDGE_NAME);
 316                 if (err < 0)
 317                         return;
 318
 319                 err = enable_bridge(BRIDGE_NAME);
 320                 if (err < 0) {
 321                         remove_bridge(BRIDGE_NAME);
 322                         return;
 323                 }
 324
 325                 tethering_dhcp_server =
 326                         dhcp_server_start(BRIDGE_NAME,
 327                                                 BRIDGE_IP, BRIDGE_SUBNET,
 328                                                 BRIDGE_IP_START, BRIDGE_IP_END,
 329                                                         24 * 3600, BRIDGE_DNS);
 330                 if (tethering_dhcp_server == NULL) {
 331                         disable_bridge(BRIDGE_NAME);
 332                         remove_bridge(BRIDGE_NAME);
 333                         return;
 334                 }
 335
 336                 enable_nat(default_interface);
 337
 338                 DBG("tethering started");
 339         }
 340 }
 341
 342 void __connman_tethering_set_disabled(void)
 343 {
 344         DBG("enabled %d", tethering_enabled - 1);
 345
 346         if (g_atomic_int_dec_and_test(&tethering_enabled) == TRUE) {
 347                 disable_nat(default_interface);
 348
 349                 dhcp_server_stop(tethering_dhcp_server);
 350
 351                 disable_bridge(BRIDGE_NAME);
 352
 353                 remove_bridge(BRIDGE_NAME);
 354
 355                 DBG("tethering stopped");
 356         }
 357 }
 358
 359 void __connman_tethering_update_interface(const char *interface)
 360 {
 361         DBG("interface %s", interface);
 362
 363         g_free(default_interface);
 364
 365         if (interface == NULL) {
 366                 disable_nat(interface);
 367                 default_interface = NULL;
 368
 369                 return;
 370         }
 371
 372         default_interface = g_strdup(interface);
 373
 374         if (!g_atomic_int_get(&tethering_enabled))
 375                 return;
 376
 377         enable_nat(interface);
 378 }
 379
 380 static void remove_private_network(gpointer user_data)
 381 {
 382         struct connman_private_network *pn = user_data;
 383
 384         if (pn->watch > 0) {
 385                 g_dbus_remove_watch(connection, pn->watch);
 386                 pn->watch = 0;
 387         }
 388
 389         g_free(pn->owner);
 390         g_free(pn);
 391 }
 392
 393 static void owner_disconnect(DBusConnection *connection, void *user_data)
 394 {
 395         struct connman_private_network *pn = user_data;
 396
 397         DBG("%s died", pn->owner);
 398
 399         pn->watch = 0;
 400
 401         g_hash_table_remove(pn_hash, pn->owner);
 402 }
 403
 404 int __connman_private_network_request(const char *owner)
 405 {
 406         struct connman_private_network *pn;
 407
 408         pn = g_hash_table_lookup(pn_hash, owner);
 409         if (pn != NULL)
 410                 return -EEXIST;
 411
 412         pn = g_try_new0(struct connman_private_network, 1);
 413         if (pn == NULL)
 414                 return -ENOMEM;
 415
 416         pn->owner = g_strdup(owner);
 417         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 418                                         owner_disconnect, pn, NULL);
 419
 420         g_hash_table_insert(pn_hash, pn->owner, pn);
 421
 422         return 0;
 423 }
 424
 425 int __connman_private_network_release(const char *owner)
 426 {
 427         struct connman_private_network *pn;
 428
 429         pn = g_hash_table_lookup(pn_hash, owner);
 430         if (pn == NULL)
 431                 return -EACCES;
 432
 433         g_hash_table_remove(pn_hash, owner);
 434         return 0;
 435 }
 436
 437 int __connman_tethering_init(void)
 438 {
 439         DBG("");
 440
 441         tethering_enabled = 0;
 442
 443         connection = connman_dbus_get_connection();
 444         if (connection == NULL)
 445                 return -EFAULT;
 446
 447         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 448                                                 NULL, remove_private_network);
 449
 450         return 0;
 451 }
 452
 453 void __connman_tethering_cleanup(void)
 454 {
 455         DBG("");
 456
 457         if (g_atomic_int_get(&tethering_enabled)) {
 458                 if (tethering_dhcp_server)
 459                         dhcp_server_stop(tethering_dhcp_server);
 460                 disable_bridge(BRIDGE_NAME);
 461                 remove_bridge(BRIDGE_NAME);
 462         }
 463
 464         if (connection == NULL)
 465                 return;
 466
 467         g_hash_table_destroy(pn_hash);
 468         dbus_connection_unref(connection);
 469 }