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