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 <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) {
 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)
 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         DBG("pool %p", pool);
 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         char **ns;
 196
 197         DBG("enabled %d", tethering_enabled + 1);
 198
 199         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 200                 return;
 201
 202         err = __connman_bridge_create(BRIDGE_NAME);
 203         if (err < 0) {
 204                 __sync_fetch_and_sub(&tethering_enabled, 1);
 205                 return;
 206         }
 207
 208         index = connman_inet_ifindex(BRIDGE_NAME);
 209         dhcp_ippool = __connman_ippool_create(index, 2, 252,
 210                                                 tethering_restart, NULL);
 211         if (!dhcp_ippool) {
 212                 connman_error("Fail to create IP pool");
 213                 __connman_bridge_remove(BRIDGE_NAME);
 214                 __sync_fetch_and_sub(&tethering_enabled, 1);
 215                 return;
 216         }
 217
 218         gateway = __connman_ippool_get_gateway(dhcp_ippool);
 219         broadcast = __connman_ippool_get_broadcast(dhcp_ippool);
 220         subnet_mask = __connman_ippool_get_subnet_mask(dhcp_ippool);
 221         start_ip = __connman_ippool_get_start_ip(dhcp_ippool);
 222         end_ip = __connman_ippool_get_end_ip(dhcp_ippool);
 223
 224         err = __connman_bridge_enable(BRIDGE_NAME, gateway,
 225                         __connman_ipaddress_netmask_prefix_len(subnet_mask),
 226                         broadcast);
 227         if (err < 0 && err != -EALREADY) {
 228                 __connman_ippool_unref(dhcp_ippool);
 229                 __connman_bridge_remove(BRIDGE_NAME);
 230                 __sync_fetch_and_sub(&tethering_enabled, 1);
 231                 return;
 232         }
 233
 234         ns = connman_setting_get_string_list("FallbackNameservers");
 235         if (ns) {
 236                 if (ns[0]) {
 237                         g_free(private_network_primary_dns);
 238                         private_network_primary_dns = g_strdup(ns[0]);
 239                 }
 240                 if (ns[1]) {
 241                         g_free(private_network_secondary_dns);
 242                         private_network_secondary_dns = g_strdup(ns[1]);
 243                 }
 244
 245                 DBG("Fallback ns primary %s secondary %s",
 246                         private_network_primary_dns,
 247                         private_network_secondary_dns);
 248         }
 249
 250         dns = gateway;
 251         if (__connman_dnsproxy_add_listener(index) < 0) {
 252                 connman_error("Can't add listener %s to DNS proxy",
 253                                                                 BRIDGE_NAME);
 254                 dns = private_network_primary_dns;
 255                 DBG("Serving %s nameserver to clients", dns);
 256         }
 257
 258         tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
 259                                                 gateway, subnet_mask,
 260                                                 start_ip, end_ip,
 261                                                 24 * 3600, dns);
 262         if (!tethering_dhcp_server) {
 263                 __connman_bridge_disable(BRIDGE_NAME);
 264                 __connman_ippool_unref(dhcp_ippool);
 265                 __connman_bridge_remove(BRIDGE_NAME);
 266                 __sync_fetch_and_sub(&tethering_enabled, 1);
 267                 return;
 268         }
 269
 270         prefixlen = __connman_ipaddress_netmask_prefix_len(subnet_mask);
 271         err = __connman_nat_enable(BRIDGE_NAME, start_ip, prefixlen);
 272         if (err < 0) {
 273                 connman_error("Cannot enable NAT %d/%s", err, strerror(-err));
 274                 dhcp_server_stop(tethering_dhcp_server);
 275                 __connman_bridge_disable(BRIDGE_NAME);
 276                 __connman_ippool_unref(dhcp_ippool);
 277                 __connman_bridge_remove(BRIDGE_NAME);
 278                 __sync_fetch_and_sub(&tethering_enabled, 1);
 279                 return;
 280         }
 281
 282         err = __connman_ipv6pd_setup(BRIDGE_NAME);
 283         if (err < 0 && err != -EINPROGRESS)
 284                 DBG("Cannot setup IPv6 prefix delegation %d/%s", err,
 285                         strerror(-err));
 286
 287         DBG("tethering started");
 288 }
 289
 290 void __connman_tethering_set_disabled(void)
 291 {
 292         int index;
 293
 294         DBG("enabled %d", tethering_enabled - 1);
 295
 296         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 297                 return;
 298
 299         __connman_ipv6pd_cleanup();
 300
 301         index = connman_inet_ifindex(BRIDGE_NAME);
 302         __connman_dnsproxy_remove_listener(index);
 303
 304         __connman_nat_disable(BRIDGE_NAME);
 305
 306         dhcp_server_stop(tethering_dhcp_server);
 307
 308         tethering_dhcp_server = NULL;
 309
 310         __connman_bridge_disable(BRIDGE_NAME);
 311
 312         __connman_ippool_unref(dhcp_ippool);
 313
 314         __connman_bridge_remove(BRIDGE_NAME);
 315
 316         g_free(private_network_primary_dns);
 317         private_network_primary_dns = NULL;
 318         g_free(private_network_secondary_dns);
 319         private_network_secondary_dns = NULL;
 320
 321         DBG("tethering stopped");
 322 }
 323
 324 static void setup_tun_interface(unsigned int flags, unsigned change,
 325                 void *data)
 326 {
 327         struct connman_private_network *pn = data;
 328         unsigned char prefixlen;
 329         DBusMessageIter array, dict;
 330         const char *server_ip;
 331         const char *peer_ip;
 332         const char *subnet_mask;
 333         int err;
 334
 335         DBG("index %d flags %d change %d", pn->index,  flags, change);
 336
 337         if (flags & IFF_UP)
 338                 return;
 339
 340         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 341         server_ip = __connman_ippool_get_start_ip(pn->pool);
 342         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 343         prefixlen =
 344                 __connman_ipaddress_netmask_prefix_len(subnet_mask);
 345
 346         if ((__connman_inet_modify_address(RTM_NEWADDR,
 347                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 348                                 server_ip, peer_ip, prefixlen, NULL)) < 0) {
 349                 DBG("address setting failed");
 350                 return;
 351         }
 352
 353         connman_inet_ifup(pn->index);
 354
 355         err = __connman_nat_enable(BRIDGE_NAME, server_ip, prefixlen);
 356         if (err < 0) {
 357                 connman_error("failed to enable NAT");
 358                 goto error;
 359         }
 360
 361         dbus_message_iter_init_append(pn->reply, &array);
 362
 363         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 364                                                 &pn->path);
 365
 366         connman_dbus_dict_open(&array, &dict);
 367
 368         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 369                                         DBUS_TYPE_STRING, &server_ip);
 370         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 371                                         DBUS_TYPE_STRING, &peer_ip);
 372         if (pn->primary_dns)
 373                 connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 374                                         DBUS_TYPE_STRING, &pn->primary_dns);
 375
 376         if (pn->secondary_dns)
 377                 connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 378                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 379
 380         connman_dbus_dict_close(&array, &dict);
 381
 382         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 383
 384         g_dbus_send_message(connection, pn->reply);
 385
 386         return;
 387
 388 error:
 389         pn->reply = __connman_error_failed(pn->msg, -err);
 390         g_dbus_send_message(connection, pn->reply);
 391
 392         g_hash_table_remove(pn_hash, pn->path);
 393 }
 394
 395 static void remove_private_network(gpointer user_data)
 396 {
 397         struct connman_private_network *pn = user_data;
 398
 399         __connman_nat_disable(BRIDGE_NAME);
 400         connman_rtnl_remove_watch(pn->iface_watch);
 401         __connman_ippool_unref(pn->pool);
 402
 403         if (pn->watch > 0) {
 404                 g_dbus_remove_watch(connection, pn->watch);
 405                 pn->watch = 0;
 406         }
 407
 408         close(pn->fd);
 409
 410         g_free(pn->interface);
 411         g_free(pn->owner);
 412         g_free(pn->path);
 413         g_free(pn->primary_dns);
 414         g_free(pn->secondary_dns);
 415         g_free(pn);
 416 }
 417
 418 static void owner_disconnect(DBusConnection *conn, void *user_data)
 419 {
 420         struct connman_private_network *pn = user_data;
 421
 422         DBG("%s died", pn->owner);
 423
 424         pn->watch = 0;
 425
 426         g_hash_table_remove(pn_hash, pn->path);
 427 }
 428
 429 static void ippool_disconnect(struct connman_ippool *pool, void *user_data)
 430 {
 431         struct connman_private_network *pn = user_data;
 432
 433         DBG("block used externally");
 434
 435         g_hash_table_remove(pn_hash, pn->path);
 436 }
 437
 438 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 439 {
 440         struct connman_private_network *pn;
 441         char *iface = NULL;
 442         char *path = NULL;
 443         int index, fd, err;
 444
 445         if (DBUS_TYPE_UNIX_FD < 0)
 446                 return -EINVAL;
 447
 448         fd = connman_inet_create_tunnel(&iface);
 449         if (fd < 0)
 450                 return fd;
 451
 452         path = g_strdup_printf("/tethering/%s", iface);
 453
 454         pn = g_hash_table_lookup(pn_hash, path);
 455         if (pn) {
 456                 g_free(path);
 457                 g_free(iface);
 458                 close(fd);
 459                 return -EEXIST;
 460         }
 461
 462         index = connman_inet_ifindex(iface);
 463         if (index < 0) {
 464                 err = -ENODEV;
 465                 goto error;
 466         }
 467         DBG("interface %s", iface);
 468
 469         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 470
 471         pn = g_try_new0(struct connman_private_network, 1);
 472         if (!pn) {
 473                 err = -ENOMEM;
 474                 goto error;
 475         }
 476
 477         pn->owner = g_strdup(owner);
 478         pn->path = path;
 479         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 480                                         owner_disconnect, pn, NULL);
 481         pn->msg = msg;
 482         pn->reply = dbus_message_new_method_return(pn->msg);
 483         if (!pn->reply)
 484                 goto error;
 485
 486         pn->fd = fd;
 487         pn->interface = iface;
 488         pn->index = index;
 489         pn->pool = __connman_ippool_create(pn->index, 1, 1, ippool_disconnect, pn);
 490         if (!pn->pool) {
 491                 errno = -ENOMEM;
 492                 goto error;
 493         }
 494
 495         pn->primary_dns = g_strdup(private_network_primary_dns);
 496         pn->secondary_dns = g_strdup(private_network_secondary_dns);
 497
 498         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 499                                                 setup_tun_interface, pn);
 500
 501         g_hash_table_insert(pn_hash, pn->path, pn);
 502
 503         return 0;
 504
 505 error:
 506         close(fd);
 507         g_free(iface);
 508         g_free(path);
 509         g_free(pn);
 510         return err;
 511 }
 512
 513 int __connman_private_network_release(const char *path)
 514 {
 515         struct connman_private_network *pn;
 516
 517         pn = g_hash_table_lookup(pn_hash, path);
 518         if (!pn)
 519                 return -EACCES;
 520
 521         g_hash_table_remove(pn_hash, path);
 522         return 0;
 523 }
 524
 525 int __connman_tethering_init(void)
 526 {
 527         DBG("");
 528
 529         tethering_enabled = 0;
 530
 531         connection = connman_dbus_get_connection();
 532         if (!connection)
 533                 return -EFAULT;
 534
 535         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 536                                                 NULL, remove_private_network);
 537
 538         return 0;
 539 }
 540
 541 void __connman_tethering_cleanup(void)
 542 {
 543         DBG("enabled %d", tethering_enabled);
 544
 545         __sync_synchronize();
 546         if (tethering_enabled > 0) {
 547                 if (tethering_dhcp_server)
 548                         dhcp_server_stop(tethering_dhcp_server);
 549                 __connman_bridge_disable(BRIDGE_NAME);
 550                 __connman_bridge_remove(BRIDGE_NAME);
 551                 __connman_nat_disable(BRIDGE_NAME);
 552         }
 553
 554         if (!connection)
 555                 return;
 556
 557         g_hash_table_destroy(pn_hash);
 558         dbus_connection_unref(connection);
 559 }