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 <linux/if_bridge.h>
  39
  40 #include "connman.h"
  41
  42 #include <gdhcp/gdhcp.h>
  43
  44 #include <gdbus.h>
  45
  46 #ifndef DBUS_TYPE_UNIX_FD
  47 #define DBUS_TYPE_UNIX_FD -1
  48 #endif
  49
  50 #define BRIDGE_NAME "tether"
  51 #define BRIDGE_DNS "8.8.8.8"
  52
  53 #define DEFAULT_MTU     1500
  54
  55 #define PRIVATE_NETWORK_PRIMARY_DNS BRIDGE_DNS
  56 #define PRIVATE_NETWORK_SECONDARY_DNS "8.8.4.4"
  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         const char *primary_dns;
  76         const 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
 195         DBG("enabled %d", tethering_enabled + 1);
 196
 197         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 198                 return;
 199
 200         err = __connman_bridge_create(BRIDGE_NAME);
 201         if (err < 0)
 202                 return;
 203
 204         index = connman_inet_ifindex(BRIDGE_NAME);
 205         dhcp_ippool = __connman_ippool_create(index, 2, 252,
 206                                                 tethering_restart, NULL);
 207         if (dhcp_ippool == NULL) {
 208                 connman_error("Fail to create IP pool");
 209                 __connman_bridge_remove(BRIDGE_NAME);
 210                 return;
 211         }
 212
 213         gateway = __connman_ippool_get_gateway(dhcp_ippool);
 214         broadcast = __connman_ippool_get_broadcast(dhcp_ippool);
 215         subnet_mask = __connman_ippool_get_subnet_mask(dhcp_ippool);
 216         start_ip = __connman_ippool_get_start_ip(dhcp_ippool);
 217         end_ip = __connman_ippool_get_end_ip(dhcp_ippool);
 218
 219         err = __connman_bridge_enable(BRIDGE_NAME, gateway, broadcast);
 220         if (err < 0 && err != -EALREADY) {
 221                 __connman_ippool_unref(dhcp_ippool);
 222                 __connman_bridge_remove(BRIDGE_NAME);
 223                 return;
 224         }
 225
 226         dns = gateway;
 227         if (__connman_dnsproxy_add_listener(BRIDGE_NAME) < 0) {
 228                 connman_error("Can't add listener %s to DNS proxy",
 229                                                                 BRIDGE_NAME);
 230                 dns = BRIDGE_DNS;
 231         }
 232
 233         tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
 234                                                 gateway, subnet_mask,
 235                                                 start_ip, end_ip,
 236                                                 24 * 3600, dns);
 237         if (tethering_dhcp_server == NULL) {
 238                 __connman_bridge_disable(BRIDGE_NAME);
 239                 __connman_ippool_unref(dhcp_ippool);
 240                 __connman_bridge_remove(BRIDGE_NAME);
 241                 return;
 242         }
 243
 244         prefixlen =
 245                 __connman_ipconfig_netmask_prefix_len(subnet_mask);
 246         __connman_nat_enable(BRIDGE_NAME, start_ip, prefixlen);
 247
 248         DBG("tethering started");
 249 }
 250
 251 void __connman_tethering_set_disabled(void)
 252 {
 253         DBG("enabled %d", tethering_enabled - 1);
 254
 255         __connman_dnsproxy_remove_listener(BRIDGE_NAME);
 256
 257         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 258                 return;
 259
 260         __connman_nat_disable(BRIDGE_NAME);
 261
 262         dhcp_server_stop(tethering_dhcp_server);
 263
 264         tethering_dhcp_server = NULL;
 265
 266         __connman_bridge_disable(BRIDGE_NAME);
 267
 268         __connman_ippool_unref(dhcp_ippool);
 269
 270         __connman_bridge_remove(BRIDGE_NAME);
 271
 272         DBG("tethering stopped");
 273 }
 274
 275 static void setup_tun_interface(unsigned int flags, unsigned change,
 276                 void *data)
 277 {
 278         struct connman_private_network *pn = data;
 279         unsigned char prefixlen;
 280         DBusMessageIter array, dict;
 281         const char *server_ip;
 282         const char *peer_ip;
 283         const char *subnet_mask;
 284         int err;
 285
 286         DBG("index %d flags %d change %d", pn->index,  flags, change);
 287
 288         if (flags & IFF_UP)
 289                 return;
 290
 291         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 292         server_ip = __connman_ippool_get_start_ip(pn->pool);
 293         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 294         prefixlen =
 295                 __connman_ipconfig_netmask_prefix_len(subnet_mask);
 296
 297         if ((__connman_inet_modify_address(RTM_NEWADDR,
 298                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 299                                 server_ip, peer_ip, prefixlen, NULL)) < 0) {
 300                 DBG("address setting failed");
 301                 return;
 302         }
 303
 304         connman_inet_ifup(pn->index);
 305
 306         err = __connman_nat_enable(BRIDGE_NAME, server_ip, prefixlen);
 307         if (err < 0) {
 308                 connman_error("failed to enable NAT");
 309                 goto error;
 310         }
 311
 312         dbus_message_iter_init_append(pn->reply, &array);
 313
 314         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 315                                                 &pn->path);
 316
 317         connman_dbus_dict_open(&array, &dict);
 318
 319         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 320                                         DBUS_TYPE_STRING, &server_ip);
 321         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 322                                         DBUS_TYPE_STRING, &peer_ip);
 323         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 324                                         DBUS_TYPE_STRING, &pn->primary_dns);
 325         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 326                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 327
 328         connman_dbus_dict_close(&array, &dict);
 329
 330         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 331
 332         g_dbus_send_message(connection, pn->reply);
 333
 334         return;
 335
 336 error:
 337         pn->reply = __connman_error_failed(pn->msg, -err);
 338         g_dbus_send_message(connection, pn->reply);
 339
 340         g_hash_table_remove(pn_hash, pn->path);
 341 }
 342
 343 static void remove_private_network(gpointer user_data)
 344 {
 345         struct connman_private_network *pn = user_data;
 346
 347         __connman_nat_disable(BRIDGE_NAME);
 348         connman_rtnl_remove_watch(pn->iface_watch);
 349         __connman_ippool_unref(pn->pool);
 350
 351         if (pn->watch > 0) {
 352                 g_dbus_remove_watch(connection, pn->watch);
 353                 pn->watch = 0;
 354         }
 355
 356         close(pn->fd);
 357
 358         g_free(pn->interface);
 359         g_free(pn->owner);
 360         g_free(pn->path);
 361         g_free(pn);
 362 }
 363
 364 static void owner_disconnect(DBusConnection *connection, void *user_data)
 365 {
 366         struct connman_private_network *pn = user_data;
 367
 368         DBG("%s died", pn->owner);
 369
 370         pn->watch = 0;
 371
 372         g_hash_table_remove(pn_hash, pn->path);
 373 }
 374
 375 static void ippool_disconnect(struct connman_ippool *pool, void *user_data)
 376 {
 377         struct connman_private_network *pn = user_data;
 378
 379         DBG("block used externally");
 380
 381         g_hash_table_remove(pn_hash, pn->path);
 382 }
 383
 384 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 385 {
 386         struct connman_private_network *pn;
 387         char *iface = NULL;
 388         char *path = NULL;
 389         int index, fd, err;
 390
 391         if (DBUS_TYPE_UNIX_FD < 0)
 392                 return -EINVAL;
 393
 394         fd = connman_inet_create_tunnel(&iface);
 395         if (fd < 0)
 396                 return fd;
 397
 398         path = g_strdup_printf("/tethering/%s", iface);
 399
 400         pn = g_hash_table_lookup(pn_hash, path);
 401         if (pn) {
 402                 g_free(path);
 403                 g_free(iface);
 404                 close(fd);
 405                 return -EEXIST;
 406         }
 407
 408         index = connman_inet_ifindex(iface);
 409         if (index < 0) {
 410                 err = -ENODEV;
 411                 goto error;
 412         }
 413         DBG("interface %s", iface);
 414
 415         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 416
 417         pn = g_try_new0(struct connman_private_network, 1);
 418         if (pn == NULL) {
 419                 err = -ENOMEM;
 420                 goto error;
 421         }
 422
 423         pn->owner = g_strdup(owner);
 424         pn->path = path;
 425         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 426                                         owner_disconnect, pn, NULL);
 427         pn->msg = msg;
 428         pn->reply = dbus_message_new_method_return(pn->msg);
 429         if (pn->reply == NULL)
 430                 goto error;
 431
 432         pn->fd = fd;
 433         pn->interface = iface;
 434         pn->index = index;
 435         pn->pool = __connman_ippool_create(pn->index, 1, 1, ippool_disconnect, pn);
 436         if (pn->pool == NULL) {
 437                 errno = -ENOMEM;
 438                 goto error;
 439         }
 440
 441         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 442         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 443
 444         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 445                                                 setup_tun_interface, pn);
 446
 447         g_hash_table_insert(pn_hash, pn->path, pn);
 448
 449         return 0;
 450
 451 error:
 452         close(fd);
 453         g_free(iface);
 454         g_free(path);
 455         g_free(pn);
 456         return err;
 457 }
 458
 459 int __connman_private_network_release(const char *path)
 460 {
 461         struct connman_private_network *pn;
 462
 463         pn = g_hash_table_lookup(pn_hash, path);
 464         if (pn == NULL)
 465                 return -EACCES;
 466
 467         g_hash_table_remove(pn_hash, path);
 468         return 0;
 469 }
 470
 471 int __connman_tethering_init(void)
 472 {
 473         DBG("");
 474
 475         tethering_enabled = 0;
 476
 477         connection = connman_dbus_get_connection();
 478         if (connection == NULL)
 479                 return -EFAULT;
 480
 481         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 482                                                 NULL, remove_private_network);
 483
 484         return 0;
 485 }
 486
 487 void __connman_tethering_cleanup(void)
 488 {
 489         DBG("");
 490
 491         __sync_synchronize();
 492         if (tethering_enabled == 0) {
 493                 if (tethering_dhcp_server)
 494                         dhcp_server_stop(tethering_dhcp_server);
 495                 __connman_bridge_disable(BRIDGE_NAME);
 496                 __connman_bridge_remove(BRIDGE_NAME);
 497                 __connman_nat_disable(BRIDGE_NAME);
 498         }
 499
 500         if (connection == NULL)
 501                 return;
 502
 503         g_hash_table_destroy(pn_hash);
 504         dbus_connection_unref(connection);
 505 }