src/tethering.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2010  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 <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <unistd.h>
  30 #include <stdio.h>
  31 #include <sys/ioctl.h>
  32 #include <net/if.h>
  33 #include <linux/sockios.h>
  34 #include <string.h>
  35 #include <fcntl.h>
  36 #include <linux/if_tun.h>
  37
  38 #include "connman.h"
  39
  40 #include <gdhcp/gdhcp.h>
  41
  42 #include <gdbus.h>
  43
  44 #ifndef DBUS_TYPE_UNIX_FD
  45 #define DBUS_TYPE_UNIX_FD -1
  46 #endif
  47
  48 #define BRIDGE_PROC_DIR "/proc/sys/net/bridge"
  49
  50 #define BRIDGE_NAME "tether"
  51 #define BRIDGE_IP "192.168.218.1"
  52 #define BRIDGE_BCAST "192.168.218.255"
  53 #define BRIDGE_SUBNET "255.255.255.0"
  54 #define BRIDGE_IP_START "192.168.218.100"
  55 #define BRIDGE_IP_END "192.168.218.200"
  56 #define BRIDGE_DNS "8.8.8.8"
  57
  58 #define DEFAULT_MTU     1500
  59
  60 #define PRIVATE_NETWORK_IP "192.168.219.1"
  61 #define PRIVATE_NETWORK_PEER_IP "192.168.219.2"
  62 #define PRIVATE_NETWORK_NETMASK "255.255.255.0"
  63 #define PRIVATE_NETWORK_PRIMARY_DNS BRIDGE_DNS
  64 #define PRIVATE_NETWORK_SECONDARY_DNS "8.8.4.4"
  65
  66 static char *default_interface = NULL;
  67 static volatile gint tethering_enabled;
  68 static GDHCPServer *tethering_dhcp_server = NULL;
  69 static DBusConnection *connection;
  70 static GHashTable *pn_hash;
  71
  72 struct connman_private_network {
  73         char *owner;
  74         guint watch;
  75         DBusMessage *msg;
  76         DBusMessage *reply;
  77         int fd;
  78         char *interface;
  79         int index;
  80         guint iface_watch;
  81         const char *server_ip;
  82         const char *peer_ip;
  83         const char *primary_dns;
  84         const char *secondary_dns;
  85 };
  86
  87 const char *__connman_tethering_get_bridge(void)
  88 {
  89         struct stat st;
  90
  91         if (stat(BRIDGE_PROC_DIR, &st) < 0) {
  92                 connman_error("Missing support for 802.1d ethernet bridging");
  93                 return NULL;
  94         }
  95
  96         return BRIDGE_NAME;
  97 }
  98
  99 static void dhcp_server_debug(const char *str, void *data)
 100 {
 101         connman_info("%s: %s\n", (const char *) data, str);
 102 }
 103
 104 static void dhcp_server_error(GDHCPServerError error)
 105 {
 106         switch (error) {
 107         case G_DHCP_SERVER_ERROR_NONE:
 108                 connman_error("OK");
 109                 break;
 110         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
 111                 connman_error("Interface unavailable");
 112                 break;
 113         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
 114                 connman_error("Interface in use");
 115                 break;
 116         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
 117                 connman_error("Interface down");
 118                 break;
 119         case G_DHCP_SERVER_ERROR_NOMEM:
 120                 connman_error("No memory");
 121                 break;
 122         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
 123                 connman_error("Invalid index");
 124                 break;
 125         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 126                 connman_error("Invalid option");
 127                 break;
 128         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 129                 connman_error("Invalid address");
 130                 break;
 131         }
 132 }
 133
 134 static GDHCPServer *dhcp_server_start(const char *bridge,
 135                                 const char *router, const char* subnet,
 136                                 const char *start_ip, const char *end_ip,
 137                                 unsigned int lease_time, const char *dns)
 138 {
 139         GDHCPServerError error;
 140         GDHCPServer *dhcp_server;
 141         int index;
 142
 143         DBG("");
 144
 145         index = connman_inet_ifindex(bridge);
 146         if (index < 0)
 147                 return NULL;
 148
 149         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 150         if (dhcp_server == NULL) {
 151                 dhcp_server_error(error);
 152                 return NULL;
 153         }
 154
 155         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 156
 157         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 158         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 159         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 160         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 161         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 162
 163         g_dhcp_server_start(dhcp_server);
 164
 165         return dhcp_server;
 166 }
 167
 168 static void dhcp_server_stop(GDHCPServer *server)
 169 {
 170         if (server == NULL)
 171                 return;
 172
 173         g_dhcp_server_unref(server);
 174 }
 175
 176 static int set_forward_delay(const char *name, unsigned int delay)
 177 {
 178         FILE *f;
 179         char *forward_delay_path;
 180
 181         forward_delay_path =
 182                 g_strdup_printf("/sys/class/net/%s/bridge/forward_delay", name);
 183
 184         if (forward_delay_path == NULL)
 185                 return -ENOMEM;
 186
 187         f = fopen(forward_delay_path, "r+");
 188
 189         g_free(forward_delay_path);
 190
 191         if (f == NULL)
 192                 return -errno;
 193
 194         fprintf(f, "%d", delay);
 195
 196         fclose(f);
 197
 198         return 0;
 199 }
 200
 201 static int create_bridge(const char *name)
 202 {
 203         int sk, err;
 204
 205         DBG("name %s", name);
 206
 207         sk = socket(AF_INET, SOCK_STREAM, 0);
 208         if (sk < 0)
 209                 return -EOPNOTSUPP;
 210
 211         err = ioctl(sk, SIOCBRADDBR, name);
 212
 213         if (err < 0)
 214                 return -EOPNOTSUPP;
 215
 216         err = set_forward_delay(name, 0);
 217
 218         if (err < 0)
 219                 ioctl(sk, SIOCBRDELBR, name);
 220
 221         close(sk);
 222
 223         return err;
 224 }
 225
 226 static int remove_bridge(const char *name)
 227 {
 228         int sk, err;
 229
 230         DBG("name %s", name);
 231
 232         sk = socket(AF_INET, SOCK_STREAM, 0);
 233         if (sk < 0)
 234                 return -EOPNOTSUPP;
 235
 236         err = ioctl(sk, SIOCBRDELBR, name);
 237
 238         close(sk);
 239
 240         if (err < 0)
 241                 return -EOPNOTSUPP;
 242
 243         return 0;
 244 }
 245
 246 static int enable_bridge(const char *name)
 247 {
 248         int err, index;
 249
 250         index = connman_inet_ifindex(name);
 251         if (index < 0)
 252                 return index;
 253
 254         err = __connman_inet_modify_address(RTM_NEWADDR,
 255                         NLM_F_REPLACE | NLM_F_ACK, index, AF_INET,
 256                                         BRIDGE_IP, NULL, 24, BRIDGE_BCAST);
 257         if (err < 0)
 258                 return err;
 259
 260         return connman_inet_ifup(index);
 261 }
 262
 263 static int disable_bridge(const char *name)
 264 {
 265         int index;
 266
 267         index = connman_inet_ifindex(name);
 268         if (index < 0)
 269                 return index;
 270
 271         return connman_inet_ifdown(index);
 272 }
 273
 274 static int enable_ip_forward(connman_bool_t enable)
 275 {
 276
 277         FILE *f;
 278
 279         f = fopen("/proc/sys/net/ipv4/ip_forward", "r+");
 280         if (f == NULL)
 281                 return -errno;
 282
 283         if (enable == TRUE)
 284                 fprintf(f, "1");
 285         else
 286                 fprintf(f, "0");
 287
 288         fclose(f);
 289
 290         return 0;
 291 }
 292
 293 static int enable_nat(const char *interface)
 294 {
 295         int err;
 296
 297         if (interface == NULL)
 298                 return 0;
 299
 300         /* Enable IPv4 forwarding */
 301         err = enable_ip_forward(TRUE);
 302         if (err < 0)
 303                 return err;
 304
 305         /* POSTROUTING flush */
 306         err = __connman_iptables_command("-t nat -F POSTROUTING");
 307         if (err < 0)
 308                 return err;
 309
 310         /* Enable masquerading */
 311         err = __connman_iptables_command("-t nat -A POSTROUTING "
 312                                         "-o %s -j MASQUERADE", interface);
 313         if (err < 0)
 314                 return err;
 315
 316         return __connman_iptables_commit("nat");
 317 }
 318
 319 static void disable_nat(const char *interface)
 320 {
 321         int err;
 322
 323         /* Disable IPv4 forwarding */
 324         enable_ip_forward(FALSE);
 325
 326         /* POSTROUTING flush */
 327         err = __connman_iptables_command("-t nat -F POSTROUTING");
 328         if (err < 0)
 329                 return;
 330
 331         __connman_iptables_commit("nat");
 332 }
 333
 334 void __connman_tethering_set_enabled(void)
 335 {
 336         int err;
 337
 338         DBG("enabled %d", tethering_enabled + 1);
 339
 340         if (g_atomic_int_exchange_and_add(&tethering_enabled, 1) == 0) {
 341                 const char *dns;
 342
 343                 err = create_bridge(BRIDGE_NAME);
 344                 if (err < 0)
 345                         return;
 346
 347                 err = enable_bridge(BRIDGE_NAME);
 348                 if (err < 0) {
 349                         remove_bridge(BRIDGE_NAME);
 350                         return;
 351                 }
 352
 353                 dns = BRIDGE_IP;
 354                 if (__connman_dnsproxy_add_listener(BRIDGE_NAME) < 0) {
 355                         connman_error("Can't add listener %s to DNS proxy",
 356                                                                 BRIDGE_NAME);
 357                         dns = BRIDGE_DNS;
 358                 }
 359
 360                 tethering_dhcp_server =
 361                         dhcp_server_start(BRIDGE_NAME,
 362                                                 BRIDGE_IP, BRIDGE_SUBNET,
 363                                                 BRIDGE_IP_START, BRIDGE_IP_END,
 364                                                         24 * 3600, dns);
 365                 if (tethering_dhcp_server == NULL) {
 366                         disable_bridge(BRIDGE_NAME);
 367                         remove_bridge(BRIDGE_NAME);
 368                         return;
 369                 }
 370
 371                 enable_nat(default_interface);
 372
 373                 DBG("tethering started");
 374         }
 375 }
 376
 377 void __connman_tethering_set_disabled(void)
 378 {
 379         DBG("enabled %d", tethering_enabled - 1);
 380
 381         __connman_dnsproxy_remove_listener(BRIDGE_NAME);
 382
 383         if (g_atomic_int_dec_and_test(&tethering_enabled) == TRUE) {
 384                 disable_nat(default_interface);
 385
 386                 dhcp_server_stop(tethering_dhcp_server);
 387
 388                 disable_bridge(BRIDGE_NAME);
 389
 390                 remove_bridge(BRIDGE_NAME);
 391
 392                 DBG("tethering stopped");
 393         }
 394 }
 395
 396 void __connman_tethering_update_interface(const char *interface)
 397 {
 398         DBG("interface %s", interface);
 399
 400         g_free(default_interface);
 401
 402         if (interface == NULL) {
 403                 disable_nat(interface);
 404                 default_interface = NULL;
 405
 406                 return;
 407         }
 408
 409         default_interface = g_strdup(interface);
 410
 411         if (!g_atomic_int_get(&tethering_enabled))
 412                 return;
 413
 414         enable_nat(interface);
 415 }
 416
 417 static void setup_tun_interface(unsigned int flags, unsigned change,
 418                 void *data)
 419 {
 420         struct connman_private_network *pn = data;
 421         unsigned char prefixlen;
 422         DBusMessage *reply;
 423         DBusMessageIter array, dict;
 424         int err;
 425
 426         DBG("index %d flags %d change %d", pn->index,  flags, change);
 427
 428         if (flags & IFF_UP)
 429                 return;
 430
 431         prefixlen =
 432                 __connman_ipconfig_netmask_prefix_len(PRIVATE_NETWORK_NETMASK);
 433
 434         if ((__connman_inet_modify_address(RTM_NEWADDR,
 435                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 436                                 pn->server_ip, pn->peer_ip,
 437                                 prefixlen, NULL)) < 0) {
 438                 DBG("address setting failed");
 439                 return;
 440         }
 441
 442         connman_inet_ifup(pn->index);
 443
 444         err = enable_nat(default_interface);
 445         if (err < 0) {
 446                 connman_error("failed to enable NAT on %s", default_interface);
 447                 goto error;
 448         }
 449
 450         reply = dbus_message_new_method_return(pn->msg);
 451
 452         if (reply == NULL)
 453                 goto error;
 454
 455         dbus_message_iter_init_append(reply, &array);
 456
 457         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 458
 459         connman_dbus_dict_open(&array, &dict);
 460
 461         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 462                                                 DBUS_TYPE_STRING, &pn->server_ip);
 463         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 464                                                 DBUS_TYPE_STRING, &pn->peer_ip);
 465         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 466                                                 DBUS_TYPE_STRING, &pn->primary_dns);
 467         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 468                                                 DBUS_TYPE_STRING, &pn->secondary_dns);
 469
 470         connman_dbus_dict_close(&array, &dict);
 471
 472         g_dbus_send_message(connection, reply);
 473
 474         return;
 475
 476 error:
 477         reply = __connman_error_failed(pn->msg, -err);
 478         g_dbus_send_message(connection, reply);
 479
 480         g_hash_table_remove(pn_hash, pn->owner);
 481 }
 482
 483 static void remove_private_network(gpointer user_data)
 484 {
 485         struct connman_private_network *pn = user_data;
 486
 487         close(pn->fd);
 488
 489         connman_rtnl_remove_watch(pn->iface_watch);
 490
 491         disable_nat(default_interface);
 492
 493         if (pn->watch > 0) {
 494                 g_dbus_remove_watch(connection, pn->watch);
 495                 pn->watch = 0;
 496         }
 497
 498         g_free(pn->interface);
 499         g_free(pn->owner);
 500         g_free(pn);
 501 }
 502
 503 static void owner_disconnect(DBusConnection *connection, void *user_data)
 504 {
 505         struct connman_private_network *pn = user_data;
 506
 507         DBG("%s died", pn->owner);
 508
 509         pn->watch = 0;
 510
 511         g_hash_table_remove(pn_hash, pn->owner);
 512 }
 513
 514 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 515 {
 516         struct connman_private_network *pn;
 517         char *iface = NULL;
 518         int index, fd, err;
 519
 520         if (DBUS_TYPE_UNIX_FD < 0)
 521                 return -EINVAL;
 522
 523         pn = g_hash_table_lookup(pn_hash, owner);
 524         if (pn != NULL)
 525                 return -EEXIST;
 526
 527         fd = connman_inet_create_tunnel(&iface);
 528         if (fd < 0)
 529                 return fd;
 530
 531         index = connman_inet_ifindex(iface);
 532         if (index < 0) {
 533                 err = -ENODEV;
 534                 goto error;
 535         }
 536         DBG("interface %s", iface);
 537
 538         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 539
 540         pn = g_try_new0(struct connman_private_network, 1);
 541         if (pn == NULL) {
 542                 err = -ENOMEM;
 543                 goto error;
 544         }
 545
 546         pn->owner = g_strdup(owner);
 547         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 548                                         owner_disconnect, pn, NULL);
 549         pn->msg = msg;
 550         pn->fd = fd;
 551         pn->interface = iface;
 552         pn->index = index;
 553         pn->server_ip = PRIVATE_NETWORK_IP;
 554         pn->peer_ip = PRIVATE_NETWORK_PEER_IP;
 555         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 556         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 557
 558         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 559                                                 setup_tun_interface, pn);
 560
 561         g_hash_table_insert(pn_hash, pn->owner, pn);
 562
 563         return 0;
 564
 565 error:
 566         close(fd);
 567         g_free(iface);
 568         return err;
 569 }
 570
 571 int __connman_private_network_release(const char *owner)
 572 {
 573         struct connman_private_network *pn;
 574
 575         pn = g_hash_table_lookup(pn_hash, owner);
 576         if (pn == NULL)
 577                 return -EACCES;
 578
 579         g_hash_table_remove(pn_hash, owner);
 580         return 0;
 581 }
 582
 583 int __connman_tethering_init(void)
 584 {
 585         DBG("");
 586
 587         tethering_enabled = 0;
 588
 589         connection = connman_dbus_get_connection();
 590         if (connection == NULL)
 591                 return -EFAULT;
 592
 593         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 594                                                 NULL, remove_private_network);
 595
 596         return 0;
 597 }
 598
 599 void __connman_tethering_cleanup(void)
 600 {
 601         DBG("");
 602
 603         if (g_atomic_int_get(&tethering_enabled)) {
 604                 if (tethering_dhcp_server)
 605                         dhcp_server_stop(tethering_dhcp_server);
 606                 disable_bridge(BRIDGE_NAME);
 607                 remove_bridge(BRIDGE_NAME);
 608         }
 609
 610         if (connection == NULL)
 611                 return;
 612
 613         g_hash_table_destroy(pn_hash);
 614         dbus_connection_unref(connection);
 615 }