src/tethering.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2012  Intel Corporation. All rights reserved.
   6  *  Copyright (C) 2011  ProFUSION embedded systems
   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 <errno.h>
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <unistd.h>
  31 #include <stdio.h>
  32 #include <sys/ioctl.h>
  33 #include <net/if.h>
  34 #include <linux/sockios.h>
  35 #include <string.h>
  36 #include <fcntl.h>
  37 #include <linux/if_tun.h>
  38 #include <netinet/in.h>
  39 #include <linux/if_bridge.h>
  40
  41 #include "connman.h"
  42
  43 #include <gdhcp/gdhcp.h>
  44
  45 #include <gdbus.h>
  46
  47 #ifndef DBUS_TYPE_UNIX_FD
  48 #define DBUS_TYPE_UNIX_FD -1
  49 #endif
  50
  51 #define BRIDGE_NAME "tether"
  52 #define BRIDGE_DNS "8.8.8.8"
  53
  54 #define DEFAULT_MTU     1500
  55
  56 #define PRIVATE_NETWORK_PRIMARY_DNS BRIDGE_DNS
  57 #define PRIVATE_NETWORK_SECONDARY_DNS "8.8.4.4"
  58
  59 static volatile int tethering_enabled;
  60 static GDHCPServer *tethering_dhcp_server = NULL;
  61 static struct connman_ippool *dhcp_ippool = NULL;
  62 static DBusConnection *connection;
  63 static GHashTable *pn_hash;
  64
  65 struct connman_private_network {
  66         char *owner;
  67         char *path;
  68         guint watch;
  69         DBusMessage *msg;
  70         DBusMessage *reply;
  71         int fd;
  72         char *interface;
  73         int index;
  74         guint iface_watch;
  75         struct connman_ippool *pool;
  76         const char *primary_dns;
  77         const char *secondary_dns;
  78 };
  79
  80 const char *__connman_tethering_get_bridge(void)
  81 {
  82         int sk, err;
  83         unsigned long args[3];
  84
  85         sk = socket(AF_INET, SOCK_STREAM, 0);
  86         if (sk < 0)
  87                 return NULL;
  88
  89         args[0] = BRCTL_GET_VERSION;
  90         args[1] = args[2] = 0;
  91         err = ioctl(sk, SIOCGIFBR, &args);
  92         close(sk);
  93         if (err == -1) {
  94                 connman_error("Missing support for 802.1d ethernet bridging");
  95                 return NULL;
  96         }
  97
  98         return BRIDGE_NAME;
  99 }
 100
 101 static void dhcp_server_debug(const char *str, void *data)
 102 {
 103         connman_info("%s: %s\n", (const char *) data, str);
 104 }
 105
 106 static void dhcp_server_error(GDHCPServerError error)
 107 {
 108         switch (error) {
 109         case G_DHCP_SERVER_ERROR_NONE:
 110                 connman_error("OK");
 111                 break;
 112         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
 113                 connman_error("Interface unavailable");
 114                 break;
 115         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
 116                 connman_error("Interface in use");
 117                 break;
 118         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
 119                 connman_error("Interface down");
 120                 break;
 121         case G_DHCP_SERVER_ERROR_NOMEM:
 122                 connman_error("No memory");
 123                 break;
 124         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
 125                 connman_error("Invalid index");
 126                 break;
 127         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 128                 connman_error("Invalid option");
 129                 break;
 130         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 131                 connman_error("Invalid address");
 132                 break;
 133         }
 134 }
 135
 136 static GDHCPServer *dhcp_server_start(const char *bridge,
 137                                 const char *router, const char* subnet,
 138                                 const char *start_ip, const char *end_ip,
 139                                 unsigned int lease_time, const char *dns)
 140 {
 141         GDHCPServerError error;
 142         GDHCPServer *dhcp_server;
 143         int index;
 144
 145         DBG("");
 146
 147         index = connman_inet_ifindex(bridge);
 148         if (index < 0)
 149                 return NULL;
 150
 151         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 152         if (dhcp_server == NULL) {
 153                 dhcp_server_error(error);
 154                 return NULL;
 155         }
 156
 157         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 158
 159         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 160         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 161         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 162         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 163         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 164
 165         g_dhcp_server_start(dhcp_server);
 166
 167         return dhcp_server;
 168 }
 169
 170 static void dhcp_server_stop(GDHCPServer *server)
 171 {
 172         if (server == NULL)
 173                 return;
 174
 175         g_dhcp_server_unref(server);
 176 }
 177
 178 static void tethering_restart(struct connman_ippool *pool, void *user_data)
 179 {
 180         __connman_tethering_set_disabled();
 181         __connman_tethering_set_enabled();
 182 }
 183
 184 void __connman_tethering_set_enabled(void)
 185 {
 186         int index;
 187         int err;
 188         const char *gateway;
 189         const char *broadcast;
 190         const char *subnet_mask;
 191         const char *start_ip;
 192         const char *end_ip;
 193         const char *dns;
 194         unsigned char prefixlen;
 195
 196         DBG("enabled %d", tethering_enabled + 1);
 197
 198         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 199                 return;
 200
 201         err = __connman_bridge_create(BRIDGE_NAME);
 202         if (err < 0) {
 203                 __sync_fetch_and_sub(&tethering_enabled, 1);
 204                 return;
 205         }
 206
 207         index = connman_inet_ifindex(BRIDGE_NAME);
 208         dhcp_ippool = __connman_ippool_create(index, 2, 252,
 209                                                 tethering_restart, NULL);
 210         if (dhcp_ippool == NULL) {
 211                 connman_error("Fail to create IP pool");
 212                 __connman_bridge_remove(BRIDGE_NAME);
 213                 __sync_fetch_and_sub(&tethering_enabled, 1);
 214                 return;
 215         }
 216
 217         gateway = __connman_ippool_get_gateway(dhcp_ippool);
 218         broadcast = __connman_ippool_get_broadcast(dhcp_ippool);
 219         subnet_mask = __connman_ippool_get_subnet_mask(dhcp_ippool);
 220         start_ip = __connman_ippool_get_start_ip(dhcp_ippool);
 221         end_ip = __connman_ippool_get_end_ip(dhcp_ippool);
 222
 223         err = __connman_bridge_enable(BRIDGE_NAME, gateway, broadcast);
 224         if (err < 0 && err != -EALREADY) {
 225                 __connman_ippool_unref(dhcp_ippool);
 226                 __connman_bridge_remove(BRIDGE_NAME);
 227                 __sync_fetch_and_sub(&tethering_enabled, 1);
 228                 return;
 229         }
 230
 231         dns = gateway;
 232         if (__connman_dnsproxy_add_listener(index) < 0) {
 233                 connman_error("Can't add listener %s to DNS proxy",
 234                                                                 BRIDGE_NAME);
 235                 dns = BRIDGE_DNS;
 236         }
 237
 238         tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
 239                                                 gateway, subnet_mask,
 240                                                 start_ip, end_ip,
 241                                                 24 * 3600, dns);
 242         if (tethering_dhcp_server == NULL) {
 243                 __connman_bridge_disable(BRIDGE_NAME);
 244                 __connman_ippool_unref(dhcp_ippool);
 245                 __connman_bridge_remove(BRIDGE_NAME);
 246                 __sync_fetch_and_sub(&tethering_enabled, 1);
 247                 return;
 248         }
 249
 250         prefixlen =
 251                 __connman_ipaddress_netmask_prefix_len(subnet_mask);
 252         __connman_nat_enable(BRIDGE_NAME, start_ip, prefixlen);
 253
 254         DBG("tethering started");
 255 }
 256
 257 void __connman_tethering_set_disabled(void)
 258 {
 259         int index;
 260
 261         DBG("enabled %d", tethering_enabled - 1);
 262
 263         index = connman_inet_ifindex(BRIDGE_NAME);
 264         __connman_dnsproxy_remove_listener(index);
 265
 266         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 267                 return;
 268
 269         __connman_nat_disable(BRIDGE_NAME);
 270
 271         dhcp_server_stop(tethering_dhcp_server);
 272
 273         tethering_dhcp_server = NULL;
 274
 275         __connman_bridge_disable(BRIDGE_NAME);
 276
 277         __connman_ippool_unref(dhcp_ippool);
 278
 279         __connman_bridge_remove(BRIDGE_NAME);
 280
 281         DBG("tethering stopped");
 282 }
 283
 284 static void setup_tun_interface(unsigned int flags, unsigned change,
 285                 void *data)
 286 {
 287         struct connman_private_network *pn = data;
 288         unsigned char prefixlen;
 289         DBusMessageIter array, dict;
 290         const char *server_ip;
 291         const char *peer_ip;
 292         const char *subnet_mask;
 293         int err;
 294
 295         DBG("index %d flags %d change %d", pn->index,  flags, change);
 296
 297         if (flags & IFF_UP)
 298                 return;
 299
 300         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 301         server_ip = __connman_ippool_get_start_ip(pn->pool);
 302         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 303         prefixlen =
 304                 __connman_ipaddress_netmask_prefix_len(subnet_mask);
 305
 306         if ((__connman_inet_modify_address(RTM_NEWADDR,
 307                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 308                                 server_ip, peer_ip, prefixlen, NULL)) < 0) {
 309                 DBG("address setting failed");
 310                 return;
 311         }
 312
 313         connman_inet_ifup(pn->index);
 314
 315         err = __connman_nat_enable(BRIDGE_NAME, server_ip, prefixlen);
 316         if (err < 0) {
 317                 connman_error("failed to enable NAT");
 318                 goto error;
 319         }
 320
 321         dbus_message_iter_init_append(pn->reply, &array);
 322
 323         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 324                                                 &pn->path);
 325
 326         connman_dbus_dict_open(&array, &dict);
 327
 328         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 329                                         DBUS_TYPE_STRING, &server_ip);
 330         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 331                                         DBUS_TYPE_STRING, &peer_ip);
 332         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 333                                         DBUS_TYPE_STRING, &pn->primary_dns);
 334         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 335                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 336
 337         connman_dbus_dict_close(&array, &dict);
 338
 339         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 340
 341         g_dbus_send_message(connection, pn->reply);
 342
 343         return;
 344
 345 error:
 346         pn->reply = __connman_error_failed(pn->msg, -err);
 347         g_dbus_send_message(connection, pn->reply);
 348
 349         g_hash_table_remove(pn_hash, pn->path);
 350 }
 351
 352 static void remove_private_network(gpointer user_data)
 353 {
 354         struct connman_private_network *pn = user_data;
 355
 356         __connman_nat_disable(BRIDGE_NAME);
 357         connman_rtnl_remove_watch(pn->iface_watch);
 358         __connman_ippool_unref(pn->pool);
 359
 360         if (pn->watch > 0) {
 361                 g_dbus_remove_watch(connection, pn->watch);
 362                 pn->watch = 0;
 363         }
 364
 365         close(pn->fd);
 366
 367         g_free(pn->interface);
 368         g_free(pn->owner);
 369         g_free(pn->path);
 370         g_free(pn);
 371 }
 372
 373 static void owner_disconnect(DBusConnection *conn, void *user_data)
 374 {
 375         struct connman_private_network *pn = user_data;
 376
 377         DBG("%s died", pn->owner);
 378
 379         pn->watch = 0;
 380
 381         g_hash_table_remove(pn_hash, pn->path);
 382 }
 383
 384 static void ippool_disconnect(struct connman_ippool *pool, void *user_data)
 385 {
 386         struct connman_private_network *pn = user_data;
 387
 388         DBG("block used externally");
 389
 390         g_hash_table_remove(pn_hash, pn->path);
 391 }
 392
 393 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 394 {
 395         struct connman_private_network *pn;
 396         char *iface = NULL;
 397         char *path = NULL;
 398         int index, fd, err;
 399
 400         if (DBUS_TYPE_UNIX_FD < 0)
 401                 return -EINVAL;
 402
 403         fd = connman_inet_create_tunnel(&iface);
 404         if (fd < 0)
 405                 return fd;
 406
 407         path = g_strdup_printf("/tethering/%s", iface);
 408
 409         pn = g_hash_table_lookup(pn_hash, path);
 410         if (pn) {
 411                 g_free(path);
 412                 g_free(iface);
 413                 close(fd);
 414                 return -EEXIST;
 415         }
 416
 417         index = connman_inet_ifindex(iface);
 418         if (index < 0) {
 419                 err = -ENODEV;
 420                 goto error;
 421         }
 422         DBG("interface %s", iface);
 423
 424         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 425
 426         pn = g_try_new0(struct connman_private_network, 1);
 427         if (pn == NULL) {
 428                 err = -ENOMEM;
 429                 goto error;
 430         }
 431
 432         pn->owner = g_strdup(owner);
 433         pn->path = path;
 434         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 435                                         owner_disconnect, pn, NULL);
 436         pn->msg = msg;
 437         pn->reply = dbus_message_new_method_return(pn->msg);
 438         if (pn->reply == NULL)
 439                 goto error;
 440
 441         pn->fd = fd;
 442         pn->interface = iface;
 443         pn->index = index;
 444         pn->pool = __connman_ippool_create(pn->index, 1, 1, ippool_disconnect, pn);
 445         if (pn->pool == NULL) {
 446                 errno = -ENOMEM;
 447                 goto error;
 448         }
 449
 450         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 451         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 452
 453         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 454                                                 setup_tun_interface, pn);
 455
 456         g_hash_table_insert(pn_hash, pn->path, pn);
 457
 458         return 0;
 459
 460 error:
 461         close(fd);
 462         g_free(iface);
 463         g_free(path);
 464         g_free(pn);
 465         return err;
 466 }
 467
 468 int __connman_private_network_release(const char *path)
 469 {
 470         struct connman_private_network *pn;
 471
 472         pn = g_hash_table_lookup(pn_hash, path);
 473         if (pn == NULL)
 474                 return -EACCES;
 475
 476         g_hash_table_remove(pn_hash, path);
 477         return 0;
 478 }
 479
 480 int __connman_tethering_init(void)
 481 {
 482         DBG("");
 483
 484         tethering_enabled = 0;
 485
 486         connection = connman_dbus_get_connection();
 487         if (connection == NULL)
 488                 return -EFAULT;
 489
 490         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 491                                                 NULL, remove_private_network);
 492
 493         return 0;
 494 }
 495
 496 void __connman_tethering_cleanup(void)
 497 {
 498         DBG("");
 499
 500         __sync_synchronize();
 501         if (tethering_enabled == 0) {
 502                 if (tethering_dhcp_server)
 503                         dhcp_server_stop(tethering_dhcp_server);
 504                 __connman_bridge_disable(BRIDGE_NAME);
 505                 __connman_bridge_remove(BRIDGE_NAME);
 506                 __connman_nat_disable(BRIDGE_NAME);
 507         }
 508
 509         if (connection == NULL)
 510                 return;
 511
 512         g_hash_table_destroy(pn_hash);
 513         dbus_connection_unref(connection);
 514 }