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
  53 #define DEFAULT_MTU     1500
  54
  55 static char *private_network_primary_dns = NULL;
  56 static char *private_network_secondary_dns = NULL;
  57
  58 static volatile int tethering_enabled;
  59 static GDHCPServer *tethering_dhcp_server = NULL;
  60 static struct connman_ippool *dhcp_ippool = NULL;
  61 static DBusConnection *connection;
  62 static GHashTable *pn_hash;
  63
  64 struct connman_private_network {
  65         char *owner;
  66         char *path;
  67         guint watch;
  68         DBusMessage *msg;
  69         DBusMessage *reply;
  70         int fd;
  71         char *interface;
  72         int index;
  73         guint iface_watch;
  74         struct connman_ippool *pool;
  75         char *primary_dns;
  76         char *secondary_dns;
  77 };
  78
  79 const char *__connman_tethering_get_bridge(void)
  80 {
  81         int sk, err;
  82         unsigned long args[3];
  83
  84         sk = socket(AF_INET, SOCK_STREAM, 0);
  85         if (sk < 0)
  86                 return NULL;
  87
  88         args[0] = BRCTL_GET_VERSION;
  89         args[1] = args[2] = 0;
  90         err = ioctl(sk, SIOCGIFBR, &args);
  91         close(sk);
  92         if (err == -1) {
  93                 connman_error("Missing support for 802.1d ethernet bridging");
  94                 return NULL;
  95         }
  96
  97         return BRIDGE_NAME;
  98 }
  99
 100 static void dhcp_server_debug(const char *str, void *data)
 101 {
 102         connman_info("%s: %s\n", (const char *) data, str);
 103 }
 104
 105 static void dhcp_server_error(GDHCPServerError error)
 106 {
 107         switch (error) {
 108         case G_DHCP_SERVER_ERROR_NONE:
 109                 connman_error("OK");
 110                 break;
 111         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
 112                 connman_error("Interface unavailable");
 113                 break;
 114         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
 115                 connman_error("Interface in use");
 116                 break;
 117         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
 118                 connman_error("Interface down");
 119                 break;
 120         case G_DHCP_SERVER_ERROR_NOMEM:
 121                 connman_error("No memory");
 122                 break;
 123         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
 124                 connman_error("Invalid index");
 125                 break;
 126         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 127                 connman_error("Invalid option");
 128                 break;
 129         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 130                 connman_error("Invalid address");
 131                 break;
 132         }
 133 }
 134
 135 static GDHCPServer *dhcp_server_start(const char *bridge,
 136                                 const char *router, const char* subnet,
 137                                 const char *start_ip, const char *end_ip,
 138                                 unsigned int lease_time, const char *dns)
 139 {
 140         GDHCPServerError error;
 141         GDHCPServer *dhcp_server;
 142         int index;
 143
 144         DBG("");
 145
 146         index = connman_inet_ifindex(bridge);
 147         if (index < 0)
 148                 return NULL;
 149
 150         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 151         if (dhcp_server == NULL) {
 152                 dhcp_server_error(error);
 153                 return NULL;
 154         }
 155
 156         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 157
 158         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 159         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 160         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 161         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 162         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 163
 164         g_dhcp_server_start(dhcp_server);
 165
 166         return dhcp_server;
 167 }
 168
 169 static void dhcp_server_stop(GDHCPServer *server)
 170 {
 171         if (server == NULL)
 172                 return;
 173
 174         g_dhcp_server_unref(server);
 175 }
 176
 177 static void tethering_restart(struct connman_ippool *pool, void *user_data)
 178 {
 179         __connman_tethering_set_disabled();
 180         __connman_tethering_set_enabled();
 181 }
 182
 183 void __connman_tethering_set_enabled(void)
 184 {
 185         int index;
 186         int err;
 187         const char *gateway;
 188         const char *broadcast;
 189         const char *subnet_mask;
 190         const char *start_ip;
 191         const char *end_ip;
 192         const char *dns;
 193         unsigned char prefixlen;
 194         char **ns;
 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         ns = connman_setting_get_string_list("FallbackNameservers");
 232         if (ns != NULL) {
 233                 if (ns[0] != NULL) {
 234                         g_free(private_network_primary_dns);
 235                         private_network_primary_dns = g_strdup(ns[0]);
 236                 }
 237                 if (ns[1] != NULL) {
 238                         g_free(private_network_secondary_dns);
 239                         private_network_secondary_dns = g_strdup(ns[1]);
 240                 }
 241
 242                 DBG("Fallback ns primary %s secondary %s",
 243                         private_network_primary_dns,
 244                         private_network_secondary_dns);
 245         }
 246
 247         dns = gateway;
 248         if (__connman_dnsproxy_add_listener(index) < 0) {
 249                 connman_error("Can't add listener %s to DNS proxy",
 250                                                                 BRIDGE_NAME);
 251                 dns = private_network_primary_dns;
 252                 DBG("Serving %s nameserver to clients", dns);
 253         }
 254
 255         tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
 256                                                 gateway, subnet_mask,
 257                                                 start_ip, end_ip,
 258                                                 24 * 3600, dns);
 259         if (tethering_dhcp_server == NULL) {
 260                 __connman_bridge_disable(BRIDGE_NAME);
 261                 __connman_ippool_unref(dhcp_ippool);
 262                 __connman_bridge_remove(BRIDGE_NAME);
 263                 __sync_fetch_and_sub(&tethering_enabled, 1);
 264                 return;
 265         }
 266
 267         prefixlen =
 268                 __connman_ipaddress_netmask_prefix_len(subnet_mask);
 269         __connman_nat_enable(BRIDGE_NAME, start_ip, prefixlen);
 270
 271         DBG("tethering started");
 272 }
 273
 274 void __connman_tethering_set_disabled(void)
 275 {
 276         int index;
 277
 278         DBG("enabled %d", tethering_enabled - 1);
 279
 280         index = connman_inet_ifindex(BRIDGE_NAME);
 281         __connman_dnsproxy_remove_listener(index);
 282
 283         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 284                 return;
 285
 286         __connman_nat_disable(BRIDGE_NAME);
 287
 288         dhcp_server_stop(tethering_dhcp_server);
 289
 290         tethering_dhcp_server = NULL;
 291
 292         __connman_bridge_disable(BRIDGE_NAME);
 293
 294         __connman_ippool_unref(dhcp_ippool);
 295
 296         __connman_bridge_remove(BRIDGE_NAME);
 297
 298         g_free(private_network_primary_dns);
 299         private_network_primary_dns = NULL;
 300         g_free(private_network_secondary_dns);
 301         private_network_secondary_dns = NULL;
 302
 303         DBG("tethering stopped");
 304 }
 305
 306 static void setup_tun_interface(unsigned int flags, unsigned change,
 307                 void *data)
 308 {
 309         struct connman_private_network *pn = data;
 310         unsigned char prefixlen;
 311         DBusMessageIter array, dict;
 312         const char *server_ip;
 313         const char *peer_ip;
 314         const char *subnet_mask;
 315         int err;
 316
 317         DBG("index %d flags %d change %d", pn->index,  flags, change);
 318
 319         if (flags & IFF_UP)
 320                 return;
 321
 322         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 323         server_ip = __connman_ippool_get_start_ip(pn->pool);
 324         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 325         prefixlen =
 326                 __connman_ipaddress_netmask_prefix_len(subnet_mask);
 327
 328         if ((__connman_inet_modify_address(RTM_NEWADDR,
 329                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 330                                 server_ip, peer_ip, prefixlen, NULL)) < 0) {
 331                 DBG("address setting failed");
 332                 return;
 333         }
 334
 335         connman_inet_ifup(pn->index);
 336
 337         err = __connman_nat_enable(BRIDGE_NAME, server_ip, prefixlen);
 338         if (err < 0) {
 339                 connman_error("failed to enable NAT");
 340                 goto error;
 341         }
 342
 343         dbus_message_iter_init_append(pn->reply, &array);
 344
 345         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 346                                                 &pn->path);
 347
 348         connman_dbus_dict_open(&array, &dict);
 349
 350         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 351                                         DBUS_TYPE_STRING, &server_ip);
 352         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 353                                         DBUS_TYPE_STRING, &peer_ip);
 354         if (pn->primary_dns != NULL)
 355                 connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 356                                         DBUS_TYPE_STRING, &pn->primary_dns);
 357
 358         if (pn->secondary_dns != NULL)
 359                 connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 360                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 361
 362         connman_dbus_dict_close(&array, &dict);
 363
 364         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 365
 366         g_dbus_send_message(connection, pn->reply);
 367
 368         return;
 369
 370 error:
 371         pn->reply = __connman_error_failed(pn->msg, -err);
 372         g_dbus_send_message(connection, pn->reply);
 373
 374         g_hash_table_remove(pn_hash, pn->path);
 375 }
 376
 377 static void remove_private_network(gpointer user_data)
 378 {
 379         struct connman_private_network *pn = user_data;
 380
 381         __connman_nat_disable(BRIDGE_NAME);
 382         connman_rtnl_remove_watch(pn->iface_watch);
 383         __connman_ippool_unref(pn->pool);
 384
 385         if (pn->watch > 0) {
 386                 g_dbus_remove_watch(connection, pn->watch);
 387                 pn->watch = 0;
 388         }
 389
 390         close(pn->fd);
 391
 392         g_free(pn->interface);
 393         g_free(pn->owner);
 394         g_free(pn->path);
 395         g_free(pn->primary_dns);
 396         g_free(pn->secondary_dns);
 397         g_free(pn);
 398 }
 399
 400 static void owner_disconnect(DBusConnection *conn, void *user_data)
 401 {
 402         struct connman_private_network *pn = user_data;
 403
 404         DBG("%s died", pn->owner);
 405
 406         pn->watch = 0;
 407
 408         g_hash_table_remove(pn_hash, pn->path);
 409 }
 410
 411 static void ippool_disconnect(struct connman_ippool *pool, void *user_data)
 412 {
 413         struct connman_private_network *pn = user_data;
 414
 415         DBG("block used externally");
 416
 417         g_hash_table_remove(pn_hash, pn->path);
 418 }
 419
 420 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 421 {
 422         struct connman_private_network *pn;
 423         char *iface = NULL;
 424         char *path = NULL;
 425         int index, fd, err;
 426
 427         if (DBUS_TYPE_UNIX_FD < 0)
 428                 return -EINVAL;
 429
 430         fd = connman_inet_create_tunnel(&iface);
 431         if (fd < 0)
 432                 return fd;
 433
 434         path = g_strdup_printf("/tethering/%s", iface);
 435
 436         pn = g_hash_table_lookup(pn_hash, path);
 437         if (pn) {
 438                 g_free(path);
 439                 g_free(iface);
 440                 close(fd);
 441                 return -EEXIST;
 442         }
 443
 444         index = connman_inet_ifindex(iface);
 445         if (index < 0) {
 446                 err = -ENODEV;
 447                 goto error;
 448         }
 449         DBG("interface %s", iface);
 450
 451         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 452
 453         pn = g_try_new0(struct connman_private_network, 1);
 454         if (pn == NULL) {
 455                 err = -ENOMEM;
 456                 goto error;
 457         }
 458
 459         pn->owner = g_strdup(owner);
 460         pn->path = path;
 461         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 462                                         owner_disconnect, pn, NULL);
 463         pn->msg = msg;
 464         pn->reply = dbus_message_new_method_return(pn->msg);
 465         if (pn->reply == NULL)
 466                 goto error;
 467
 468         pn->fd = fd;
 469         pn->interface = iface;
 470         pn->index = index;
 471         pn->pool = __connman_ippool_create(pn->index, 1, 1, ippool_disconnect, pn);
 472         if (pn->pool == NULL) {
 473                 errno = -ENOMEM;
 474                 goto error;
 475         }
 476
 477         pn->primary_dns = g_strdup(private_network_primary_dns);
 478         pn->secondary_dns = g_strdup(private_network_secondary_dns);
 479
 480         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 481                                                 setup_tun_interface, pn);
 482
 483         g_hash_table_insert(pn_hash, pn->path, pn);
 484
 485         return 0;
 486
 487 error:
 488         close(fd);
 489         g_free(iface);
 490         g_free(path);
 491         g_free(pn);
 492         return err;
 493 }
 494
 495 int __connman_private_network_release(const char *path)
 496 {
 497         struct connman_private_network *pn;
 498
 499         pn = g_hash_table_lookup(pn_hash, path);
 500         if (pn == NULL)
 501                 return -EACCES;
 502
 503         g_hash_table_remove(pn_hash, path);
 504         return 0;
 505 }
 506
 507 int __connman_tethering_init(void)
 508 {
 509         DBG("");
 510
 511         tethering_enabled = 0;
 512
 513         connection = connman_dbus_get_connection();
 514         if (connection == NULL)
 515                 return -EFAULT;
 516
 517         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 518                                                 NULL, remove_private_network);
 519
 520         return 0;
 521 }
 522
 523 void __connman_tethering_cleanup(void)
 524 {
 525         DBG("");
 526
 527         __sync_synchronize();
 528         if (tethering_enabled == 0) {
 529                 if (tethering_dhcp_server)
 530                         dhcp_server_stop(tethering_dhcp_server);
 531                 __connman_bridge_disable(BRIDGE_NAME);
 532                 __connman_bridge_remove(BRIDGE_NAME);
 533                 __connman_nat_disable(BRIDGE_NAME);
 534         }
 535
 536         if (connection == NULL)
 537                 return;
 538
 539         g_hash_table_destroy(pn_hash);
 540         dbus_connection_unref(connection);
 541 }