src/tethering.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2013  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 <string.h>
  35 #include <fcntl.h>
  36 #include <netinet/in.h>
  37 #include <linux/sockios.h>
  38 #include <linux/if_tun.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 static GHashTable *clients_table;
  65
  66 struct _clients_notify {
  67         int id;
  68         GHashTable *remove;
  69 } *clients_notify;
  70
  71 struct connman_private_network {
  72         char *owner;
  73         char *path;
  74         guint watch;
  75         DBusMessage *msg;
  76         DBusMessage *reply;
  77         int fd;
  78         char *interface;
  79         int index;
  80         guint iface_watch;
  81         struct connman_ippool *pool;
  82         char *primary_dns;
  83         char *secondary_dns;
  84 };
  85
  86 const char *__connman_tethering_get_bridge(void)
  87 {
  88         int sk, err;
  89         unsigned long args[3];
  90
  91         sk = socket(AF_INET, SOCK_STREAM, 0);
  92         if (sk < 0)
  93                 return NULL;
  94
  95         args[0] = BRCTL_GET_VERSION;
  96         args[1] = args[2] = 0;
  97         err = ioctl(sk, SIOCGIFBR, &args);
  98         close(sk);
  99         if (err == -1) {
 100                 connman_error("Missing support for 802.1d ethernet bridging");
 101                 return NULL;
 102         }
 103
 104         return BRIDGE_NAME;
 105 }
 106
 107 static void dhcp_server_debug(const char *str, void *data)
 108 {
 109         connman_info("%s: %s\n", (const char *) data, str);
 110 }
 111
 112 static void dhcp_server_error(GDHCPServerError error)
 113 {
 114         switch (error) {
 115         case G_DHCP_SERVER_ERROR_NONE:
 116                 connman_error("OK");
 117                 break;
 118         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
 119                 connman_error("Interface unavailable");
 120                 break;
 121         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
 122                 connman_error("Interface in use");
 123                 break;
 124         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
 125                 connman_error("Interface down");
 126                 break;
 127         case G_DHCP_SERVER_ERROR_NOMEM:
 128                 connman_error("No memory");
 129                 break;
 130         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
 131                 connman_error("Invalid index");
 132                 break;
 133         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 134                 connman_error("Invalid option");
 135                 break;
 136         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 137                 connman_error("Invalid address");
 138                 break;
 139         }
 140 }
 141
 142 static GDHCPServer *dhcp_server_start(const char *bridge,
 143                                 const char *router, const char *subnet,
 144                                 const char *start_ip, const char *end_ip,
 145                                 unsigned int lease_time, const char *dns)
 146 {
 147         GDHCPServerError error;
 148         GDHCPServer *dhcp_server;
 149         int index;
 150
 151         DBG("");
 152
 153         index = connman_inet_ifindex(bridge);
 154         if (index < 0)
 155                 return NULL;
 156
 157         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 158         if (!dhcp_server) {
 159                 dhcp_server_error(error);
 160                 return NULL;
 161         }
 162
 163         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 164
 165         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 166         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 167         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 168         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 169         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 170
 171         g_dhcp_server_start(dhcp_server);
 172
 173         return dhcp_server;
 174 }
 175
 176 static void dhcp_server_stop(GDHCPServer *server)
 177 {
 178         if (!server)
 179                 return;
 180
 181         g_dhcp_server_unref(server);
 182 }
 183
 184 static void tethering_restart(struct connman_ippool *pool, void *user_data)
 185 {
 186         DBG("pool %p", pool);
 187         __connman_tethering_set_disabled();
 188         __connman_tethering_set_enabled();
 189 }
 190
 191 static void unregister_client(gpointer key,
 192                                         gpointer value, gpointer user_data)
 193 {
 194         const char *addr = key;
 195         __connman_tethering_client_unregister(addr);
 196 }
 197
 198 static void unregister_all_clients(void)
 199 {
 200         g_hash_table_foreach(clients_table, unregister_client, NULL);
 201 }
 202
 203 int __connman_tethering_set_enabled(void)
 204 {
 205         int index;
 206         int err;
 207         const char *gateway;
 208         const char *broadcast;
 209         const char *subnet_mask;
 210         const char *start_ip;
 211         const char *end_ip;
 212         const char *dns;
 213         unsigned char prefixlen;
 214         char **ns;
 215
 216         DBG("enabled %d", tethering_enabled + 1);
 217
 218         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 219                 return 0;
 220
 221         err = __connman_bridge_create(BRIDGE_NAME);
 222         if (err < 0) {
 223                 __sync_fetch_and_sub(&tethering_enabled, 1);
 224                 return -EOPNOTSUPP;
 225         }
 226
 227         index = connman_inet_ifindex(BRIDGE_NAME);
 228         dhcp_ippool = __connman_ippool_create(index, 2, 252,
 229                                                 tethering_restart, NULL);
 230         if (!dhcp_ippool) {
 231                 connman_error("Fail to create IP pool");
 232                 __connman_bridge_remove(BRIDGE_NAME);
 233                 __sync_fetch_and_sub(&tethering_enabled, 1);
 234                 return -EADDRNOTAVAIL;
 235         }
 236
 237         gateway = __connman_ippool_get_gateway(dhcp_ippool);
 238         broadcast = __connman_ippool_get_broadcast(dhcp_ippool);
 239         subnet_mask = __connman_ippool_get_subnet_mask(dhcp_ippool);
 240         start_ip = __connman_ippool_get_start_ip(dhcp_ippool);
 241         end_ip = __connman_ippool_get_end_ip(dhcp_ippool);
 242
 243         err = __connman_bridge_enable(BRIDGE_NAME, gateway,
 244                         connman_ipaddress_calc_netmask_len(subnet_mask),
 245                         broadcast);
 246         if (err < 0 && err != -EALREADY) {
 247                 __connman_ippool_free(dhcp_ippool);
 248                 dhcp_ippool = NULL;
 249                 __connman_bridge_remove(BRIDGE_NAME);
 250                 __sync_fetch_and_sub(&tethering_enabled, 1);
 251                 return -EADDRNOTAVAIL;
 252         }
 253
 254         ns = connman_setting_get_string_list("FallbackNameservers");
 255         if (ns) {
 256                 if (ns[0]) {
 257                         g_free(private_network_primary_dns);
 258                         private_network_primary_dns = g_strdup(ns[0]);
 259                 }
 260                 if (ns[1]) {
 261                         g_free(private_network_secondary_dns);
 262                         private_network_secondary_dns = g_strdup(ns[1]);
 263                 }
 264
 265                 DBG("Fallback ns primary %s secondary %s",
 266                         private_network_primary_dns,
 267                         private_network_secondary_dns);
 268         }
 269
 270         dns = gateway;
 271         if (__connman_dnsproxy_add_listener(index) < 0) {
 272                 connman_error("Can't add listener %s to DNS proxy",
 273                                                                 BRIDGE_NAME);
 274                 dns = private_network_primary_dns;
 275                 DBG("Serving %s nameserver to clients", dns);
 276         }
 277
 278         tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
 279                                                 gateway, subnet_mask,
 280                                                 start_ip, end_ip,
 281                                                 24 * 3600, dns);
 282         if (!tethering_dhcp_server) {
 283                 __connman_bridge_disable(BRIDGE_NAME);
 284                 __connman_ippool_free(dhcp_ippool);
 285                 dhcp_ippool = NULL;
 286                 __connman_bridge_remove(BRIDGE_NAME);
 287                 __sync_fetch_and_sub(&tethering_enabled, 1);
 288                 return -EOPNOTSUPP;
 289         }
 290
 291         prefixlen = connman_ipaddress_calc_netmask_len(subnet_mask);
 292         err = __connman_nat_enable(BRIDGE_NAME, start_ip, prefixlen);
 293         if (err < 0) {
 294                 connman_error("Cannot enable NAT %d/%s", err, strerror(-err));
 295                 dhcp_server_stop(tethering_dhcp_server);
 296                 __connman_bridge_disable(BRIDGE_NAME);
 297                 __connman_ippool_free(dhcp_ippool);
 298                 dhcp_ippool = NULL;
 299                 __connman_bridge_remove(BRIDGE_NAME);
 300                 __sync_fetch_and_sub(&tethering_enabled, 1);
 301                 return -EOPNOTSUPP;
 302         }
 303
 304         err = __connman_ipv6pd_setup(BRIDGE_NAME);
 305         if (err < 0 && err != -EINPROGRESS)
 306                 DBG("Cannot setup IPv6 prefix delegation %d/%s", err,
 307                         strerror(-err));
 308
 309         DBG("tethering started");
 310
 311         return 0;
 312 }
 313
 314 void __connman_tethering_set_disabled(void)
 315 {
 316         int index;
 317
 318         DBG("enabled %d", tethering_enabled - 1);
 319
 320         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 321                 return;
 322
 323         unregister_all_clients();
 324
 325         __connman_ipv6pd_cleanup();
 326
 327         index = connman_inet_ifindex(BRIDGE_NAME);
 328         __connman_dnsproxy_remove_listener(index);
 329
 330         __connman_nat_disable(BRIDGE_NAME);
 331
 332         dhcp_server_stop(tethering_dhcp_server);
 333
 334         tethering_dhcp_server = NULL;
 335
 336         __connman_bridge_disable(BRIDGE_NAME);
 337
 338         __connman_ippool_free(dhcp_ippool);
 339         dhcp_ippool = NULL;
 340
 341         __connman_bridge_remove(BRIDGE_NAME);
 342
 343         g_free(private_network_primary_dns);
 344         private_network_primary_dns = NULL;
 345         g_free(private_network_secondary_dns);
 346         private_network_secondary_dns = NULL;
 347
 348         DBG("tethering stopped");
 349 }
 350
 351 static void append_client(gpointer key, gpointer value,
 352                                                 gpointer user_data)
 353 {
 354         const char *addr = key;
 355         DBusMessageIter *array = user_data;
 356
 357         dbus_message_iter_append_basic(array, DBUS_TYPE_STRING,
 358                                                         &addr);
 359 }
 360
 361 void __connman_tethering_list_clients(DBusMessageIter *array)
 362 {
 363         g_hash_table_foreach(clients_table, append_client, array);
 364 }
 365
 366 static void setup_tun_interface(unsigned int flags, unsigned change,
 367                 void *data)
 368 {
 369         struct connman_private_network *pn = data;
 370         unsigned char prefixlen;
 371         DBusMessageIter array, dict;
 372         const char *server_ip;
 373         const char *peer_ip;
 374         const char *subnet_mask;
 375         int err;
 376
 377         DBG("index %d flags %d change %d", pn->index,  flags, change);
 378
 379         if (flags & IFF_UP)
 380                 return;
 381
 382         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 383         server_ip = __connman_ippool_get_start_ip(pn->pool);
 384         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 385         prefixlen = connman_ipaddress_calc_netmask_len(subnet_mask);
 386
 387         if ((__connman_inet_modify_address(RTM_NEWADDR,
 388                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 389                                 server_ip, peer_ip, prefixlen, NULL, true))
 390                                 < 0) {
 391                 DBG("address setting failed");
 392                 return;
 393         }
 394
 395         connman_inet_ifup(pn->index);
 396
 397         err = __connman_nat_enable(BRIDGE_NAME, server_ip, prefixlen);
 398         if (err < 0) {
 399                 connman_error("failed to enable NAT");
 400                 goto error;
 401         }
 402
 403         dbus_message_iter_init_append(pn->reply, &array);
 404
 405         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 406                                                 &pn->path);
 407
 408         connman_dbus_dict_open(&array, &dict);
 409
 410         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 411                                         DBUS_TYPE_STRING, &server_ip);
 412         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 413                                         DBUS_TYPE_STRING, &peer_ip);
 414         if (pn->primary_dns)
 415                 connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 416                                         DBUS_TYPE_STRING, &pn->primary_dns);
 417
 418         if (pn->secondary_dns)
 419                 connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 420                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 421
 422         connman_dbus_dict_close(&array, &dict);
 423
 424         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 425
 426         g_dbus_send_message(connection, pn->reply);
 427
 428         return;
 429
 430 error:
 431         pn->reply = __connman_error_failed(pn->msg, -err);
 432         g_dbus_send_message(connection, pn->reply);
 433
 434         g_hash_table_remove(pn_hash, pn->path);
 435 }
 436
 437 static void remove_private_network(gpointer user_data)
 438 {
 439         struct connman_private_network *pn = user_data;
 440
 441         __connman_nat_disable(BRIDGE_NAME);
 442         connman_rtnl_remove_watch(pn->iface_watch);
 443         __connman_ippool_free(pn->pool);
 444
 445         if (pn->watch > 0) {
 446                 g_dbus_remove_watch(connection, pn->watch);
 447                 pn->watch = 0;
 448         }
 449
 450         close(pn->fd);
 451
 452         g_free(pn->interface);
 453         g_free(pn->owner);
 454         g_free(pn->path);
 455         g_free(pn->primary_dns);
 456         g_free(pn->secondary_dns);
 457         g_free(pn);
 458 }
 459
 460 static void owner_disconnect(DBusConnection *conn, void *user_data)
 461 {
 462         struct connman_private_network *pn = user_data;
 463
 464         DBG("%s died", pn->owner);
 465
 466         pn->watch = 0;
 467
 468         g_hash_table_remove(pn_hash, pn->path);
 469 }
 470
 471 static void ippool_disconnect(struct connman_ippool *pool, void *user_data)
 472 {
 473         struct connman_private_network *pn = user_data;
 474
 475         DBG("block used externally");
 476
 477         g_hash_table_remove(pn_hash, pn->path);
 478 }
 479
 480 static gboolean client_send_changed(gpointer data)
 481 {
 482         DBusMessage *signal;
 483         DBusMessageIter iter, array;
 484
 485         DBG("");
 486
 487         clients_notify->id = 0;
 488
 489         signal = dbus_message_new_signal(CONNMAN_MANAGER_PATH,
 490                                 CONNMAN_MANAGER_INTERFACE, "TetheringClientsChanged");
 491         if (!signal)
 492                 return FALSE;
 493
 494         dbus_message_iter_init_append(signal, &iter);
 495         dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY,
 496                                 DBUS_TYPE_STRING_AS_STRING, &array);
 497
 498         g_hash_table_foreach(clients_table, append_client, &array);
 499
 500         dbus_message_iter_close_container(&iter, &array);
 501
 502         dbus_message_iter_init_append(signal, &iter);
 503         dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY,
 504                                 DBUS_TYPE_STRING_AS_STRING, &array);
 505
 506         g_hash_table_foreach(clients_notify->remove, append_client, &array);
 507
 508         dbus_message_iter_close_container(&iter, &array);
 509
 510         dbus_connection_send(connection, signal, NULL);
 511         dbus_message_unref(signal);
 512
 513         g_hash_table_remove_all(clients_notify->remove);
 514
 515         return FALSE;
 516 }
 517
 518 static void client_schedule_changed(void)
 519 {
 520         if (clients_notify->id != 0)
 521                 return;
 522
 523         clients_notify->id = g_timeout_add(100, client_send_changed, NULL);
 524 }
 525
 526 static void client_added(const char *addr)
 527 {
 528         DBG("client %s", addr);
 529
 530         g_hash_table_remove(clients_notify->remove, addr);
 531
 532         client_schedule_changed();
 533 }
 534
 535 static void client_removed(const char *addr)
 536 {
 537         DBG("client %s", addr);
 538
 539         g_hash_table_replace(clients_notify->remove, g_strdup(addr), NULL);
 540
 541         client_schedule_changed();
 542 }
 543
 544 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 545 {
 546         struct connman_private_network *pn;
 547         char *iface = NULL;
 548         char *path = NULL;
 549         int index, fd, err;
 550
 551         if (DBUS_TYPE_UNIX_FD < 0)
 552                 return -EINVAL;
 553
 554         fd = connman_inet_create_tunnel(&iface);
 555         if (fd < 0)
 556                 return fd;
 557
 558         path = g_strdup_printf("/tethering/%s", iface);
 559
 560         pn = g_hash_table_lookup(pn_hash, path);
 561         if (pn) {
 562                 g_free(path);
 563                 g_free(iface);
 564                 close(fd);
 565                 return -EEXIST;
 566         }
 567
 568         index = connman_inet_ifindex(iface);
 569         if (index < 0) {
 570                 err = -ENODEV;
 571                 goto error;
 572         }
 573         DBG("interface %s", iface);
 574
 575         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 576
 577         pn = g_try_new0(struct connman_private_network, 1);
 578         if (!pn) {
 579                 err = -ENOMEM;
 580                 goto error;
 581         }
 582
 583         pn->owner = g_strdup(owner);
 584         pn->path = path;
 585         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 586                                         owner_disconnect, pn, NULL);
 587         pn->msg = msg;
 588         pn->reply = dbus_message_new_method_return(pn->msg);
 589         if (!pn->reply)
 590                 goto error;
 591
 592         pn->fd = fd;
 593         pn->interface = iface;
 594         pn->index = index;
 595         pn->pool = __connman_ippool_create(pn->index, 1, 1, ippool_disconnect, pn);
 596         if (!pn->pool) {
 597                 errno = -ENOMEM;
 598                 goto error;
 599         }
 600
 601         pn->primary_dns = g_strdup(private_network_primary_dns);
 602         pn->secondary_dns = g_strdup(private_network_secondary_dns);
 603
 604         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 605                                                 setup_tun_interface, pn);
 606
 607         g_hash_table_insert(pn_hash, pn->path, pn);
 608
 609         return 0;
 610
 611 error:
 612         close(fd);
 613         g_free(iface);
 614         g_free(path);
 615         if (pn)
 616                 g_free(pn->owner);
 617         g_free(pn);
 618         return err;
 619 }
 620
 621 int __connman_private_network_release(const char *path)
 622 {
 623         struct connman_private_network *pn;
 624
 625         pn = g_hash_table_lookup(pn_hash, path);
 626         if (!pn)
 627                 return -EACCES;
 628
 629         g_hash_table_remove(pn_hash, path);
 630         return 0;
 631 }
 632
 633 void __connman_tethering_client_register(const char *addr)
 634 {
 635         g_hash_table_insert(clients_table, g_strdup(addr), NULL);
 636         client_added(addr);
 637 }
 638
 639 void __connman_tethering_client_unregister(const char *addr)
 640 {
 641         client_removed(addr);
 642         g_hash_table_remove(clients_table, addr);
 643 }
 644
 645 int __connman_tethering_init(void)
 646 {
 647         DBG("");
 648
 649         tethering_enabled = 0;
 650
 651         connection = connman_dbus_get_connection();
 652         if (!connection)
 653                 return -EFAULT;
 654
 655         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 656                                                 NULL, remove_private_network);
 657
 658         clients_table = g_hash_table_new_full(g_str_hash, g_str_equal,
 659                                                         g_free, NULL);
 660
 661         clients_notify = g_new0(struct _clients_notify, 1);
 662         clients_notify->remove = g_hash_table_new_full(g_str_hash, g_str_equal,
 663                                                         g_free, NULL);
 664         return 0;
 665 }
 666
 667 void __connman_tethering_cleanup(void)
 668 {
 669         DBG("enabled %d", tethering_enabled);
 670
 671         __sync_synchronize();
 672         if (tethering_enabled > 0) {
 673                 if (tethering_dhcp_server)
 674                         dhcp_server_stop(tethering_dhcp_server);
 675                 __connman_bridge_disable(BRIDGE_NAME);
 676                 __connman_bridge_remove(BRIDGE_NAME);
 677                 __connman_nat_disable(BRIDGE_NAME);
 678         }
 679
 680         if (!connection)
 681                 return;
 682
 683         g_hash_table_destroy(pn_hash);
 684
 685         g_hash_table_destroy(clients_notify->remove);
 686         g_free(clients_notify);
 687         clients_notify = NULL;
 688
 689         g_hash_table_destroy(clients_table);
 690         clients_table = NULL;
 691
 692         dbus_connection_unref(connection);
 693 }