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 <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_IP "192.168.218.1"
  53 #define BRIDGE_BCAST "192.168.218.255"
  54 #define BRIDGE_SUBNET "255.255.255.0"
  55 #define BRIDGE_IP_START "192.168.218.100"
  56 #define BRIDGE_IP_END "192.168.218.200"
  57 #define BRIDGE_DNS "8.8.8.8"
  58
  59 #define DEFAULT_MTU     1500
  60
  61 #define PRIVATE_NETWORK_IP "192.168.219.1"
  62 #define PRIVATE_NETWORK_PEER_IP "192.168.219.2"
  63 #define PRIVATE_NETWORK_NETMASK "255.255.255.0"
  64 #define PRIVATE_NETWORK_PRIMARY_DNS BRIDGE_DNS
  65 #define PRIVATE_NETWORK_SECONDARY_DNS "8.8.4.4"
  66
  67 static char *default_interface = NULL;
  68 static volatile int tethering_enabled;
  69 static GDHCPServer *tethering_dhcp_server = NULL;
  70 static DBusConnection *connection;
  71 static GHashTable *pn_hash;
  72
  73 struct connman_private_network {
  74         char *owner;
  75         char *path;
  76         guint watch;
  77         DBusMessage *msg;
  78         DBusMessage *reply;
  79         int fd;
  80         char *interface;
  81         int index;
  82         guint iface_watch;
  83         const char *server_ip;
  84         const char *peer_ip;
  85         const char *primary_dns;
  86         const char *secondary_dns;
  87 };
  88
  89 const char *__connman_tethering_get_bridge(void)
  90 {
  91         struct stat st;
  92
  93         if (stat(BRIDGE_PROC_DIR, &st) < 0) {
  94                 connman_error("Missing support for 802.1d ethernet bridging");
  95                 return NULL;
  96         }
  97
  98         return BRIDGE_NAME;
  99 }
 100
 101 static void dhcp_server_debug(const char *str, void *data)
 102 {
 103         connman_info("%s: %s\n", (const char *) data, str);
 104 }
 105
 106 static void dhcp_server_error(GDHCPServerError error)
 107 {
 108         switch (error) {
 109         case G_DHCP_SERVER_ERROR_NONE:
 110                 connman_error("OK");
 111                 break;
 112         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
 113                 connman_error("Interface unavailable");
 114                 break;
 115         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
 116                 connman_error("Interface in use");
 117                 break;
 118         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
 119                 connman_error("Interface down");
 120                 break;
 121         case G_DHCP_SERVER_ERROR_NOMEM:
 122                 connman_error("No memory");
 123                 break;
 124         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
 125                 connman_error("Invalid index");
 126                 break;
 127         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 128                 connman_error("Invalid option");
 129                 break;
 130         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 131                 connman_error("Invalid address");
 132                 break;
 133         }
 134 }
 135
 136 static GDHCPServer *dhcp_server_start(const char *bridge,
 137                                 const char *router, const char* subnet,
 138                                 const char *start_ip, const char *end_ip,
 139                                 unsigned int lease_time, const char *dns)
 140 {
 141         GDHCPServerError error;
 142         GDHCPServer *dhcp_server;
 143         int index;
 144
 145         DBG("");
 146
 147         index = connman_inet_ifindex(bridge);
 148         if (index < 0)
 149                 return NULL;
 150
 151         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 152         if (dhcp_server == NULL) {
 153                 dhcp_server_error(error);
 154                 return NULL;
 155         }
 156
 157         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 158
 159         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 160         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 161         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 162         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 163         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 164
 165         g_dhcp_server_start(dhcp_server);
 166
 167         return dhcp_server;
 168 }
 169
 170 static void dhcp_server_stop(GDHCPServer *server)
 171 {
 172         if (server == NULL)
 173                 return;
 174
 175         g_dhcp_server_unref(server);
 176 }
 177
 178 static int set_forward_delay(const char *name, unsigned int delay)
 179 {
 180         FILE *f;
 181         char *forward_delay_path;
 182
 183         forward_delay_path =
 184                 g_strdup_printf("/sys/class/net/%s/bridge/forward_delay", name);
 185
 186         if (forward_delay_path == NULL)
 187                 return -ENOMEM;
 188
 189         f = fopen(forward_delay_path, "r+");
 190
 191         g_free(forward_delay_path);
 192
 193         if (f == NULL)
 194                 return -errno;
 195
 196         fprintf(f, "%d", delay);
 197
 198         fclose(f);
 199
 200         return 0;
 201 }
 202
 203 static int create_bridge(const char *name)
 204 {
 205         int sk, err;
 206
 207         DBG("name %s", name);
 208
 209         sk = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
 210         if (sk < 0)
 211                 return -EOPNOTSUPP;
 212
 213         if (ioctl(sk, SIOCBRADDBR, name) == -1) {
 214                 err = -errno;
 215                 if (err != -EEXIST)
 216                         return -EOPNOTSUPP;
 217         }
 218
 219         err = set_forward_delay(name, 0);
 220
 221         if (err < 0)
 222                 ioctl(sk, SIOCBRDELBR, name);
 223
 224         close(sk);
 225
 226         return err;
 227 }
 228
 229 static int remove_bridge(const char *name)
 230 {
 231         int sk, err;
 232
 233         DBG("name %s", name);
 234
 235         sk = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
 236         if (sk < 0)
 237                 return -EOPNOTSUPP;
 238
 239         err = ioctl(sk, SIOCBRDELBR, name);
 240
 241         close(sk);
 242
 243         if (err < 0)
 244                 return -EOPNOTSUPP;
 245
 246         return 0;
 247 }
 248
 249 static int enable_bridge(const char *name)
 250 {
 251         int err, index;
 252
 253         index = connman_inet_ifindex(name);
 254         if (index < 0)
 255                 return index;
 256
 257         err = __connman_inet_modify_address(RTM_NEWADDR,
 258                         NLM_F_REPLACE | NLM_F_ACK, index, AF_INET,
 259                                         BRIDGE_IP, NULL, 24, BRIDGE_BCAST);
 260         if (err < 0)
 261                 return err;
 262
 263         return connman_inet_ifup(index);
 264 }
 265
 266 static int disable_bridge(const char *name)
 267 {
 268         int index;
 269
 270         index = connman_inet_ifindex(name);
 271         if (index < 0)
 272                 return index;
 273
 274         return connman_inet_ifdown(index);
 275 }
 276
 277 static int enable_ip_forward(connman_bool_t enable)
 278 {
 279
 280         FILE *f;
 281
 282         f = fopen("/proc/sys/net/ipv4/ip_forward", "r+");
 283         if (f == NULL)
 284                 return -errno;
 285
 286         if (enable == TRUE)
 287                 fprintf(f, "1");
 288         else
 289                 fprintf(f, "0");
 290
 291         fclose(f);
 292
 293         return 0;
 294 }
 295
 296 static int enable_nat(const char *interface)
 297 {
 298         int err;
 299
 300         if (interface == NULL)
 301                 return 0;
 302
 303         /* Enable IPv4 forwarding */
 304         err = enable_ip_forward(TRUE);
 305         if (err < 0)
 306                 return err;
 307
 308         /* POSTROUTING flush */
 309         err = __connman_iptables_command("-t nat -F POSTROUTING");
 310         if (err < 0)
 311                 return err;
 312
 313         /* Enable masquerading */
 314         err = __connman_iptables_command("-t nat -A POSTROUTING "
 315                                         "-o %s -j MASQUERADE", interface);
 316         if (err < 0)
 317                 return err;
 318
 319         return __connman_iptables_commit("nat");
 320 }
 321
 322 static void disable_nat(const char *interface)
 323 {
 324         int err;
 325
 326         /* Disable IPv4 forwarding */
 327         enable_ip_forward(FALSE);
 328
 329         /* POSTROUTING flush */
 330         err = __connman_iptables_command("-t nat -F POSTROUTING");
 331         if (err < 0)
 332                 return;
 333
 334         __connman_iptables_commit("nat");
 335 }
 336
 337 void __connman_tethering_set_enabled(void)
 338 {
 339         int err;
 340         const char *dns;
 341
 342         DBG("enabled %d", tethering_enabled + 1);
 343
 344         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 345                 return;
 346
 347         err = create_bridge(BRIDGE_NAME);
 348         if (err < 0)
 349                 return;
 350
 351         err = enable_bridge(BRIDGE_NAME);
 352         if (err < 0 && err != -EALREADY) {
 353                 remove_bridge(BRIDGE_NAME);
 354                 return;
 355         }
 356
 357         dns = BRIDGE_IP;
 358         if (__connman_dnsproxy_add_listener(BRIDGE_NAME) < 0) {
 359                 connman_error("Can't add listener %s to DNS proxy",
 360                                                                 BRIDGE_NAME);
 361                 dns = BRIDGE_DNS;
 362         }
 363
 364         tethering_dhcp_server =
 365                 dhcp_server_start(BRIDGE_NAME,
 366                                         BRIDGE_IP, BRIDGE_SUBNET,
 367                                         BRIDGE_IP_START, BRIDGE_IP_END,
 368                                         24 * 3600, dns);
 369         if (tethering_dhcp_server == NULL) {
 370                 disable_bridge(BRIDGE_NAME);
 371                 remove_bridge(BRIDGE_NAME);
 372                 return;
 373         }
 374
 375         enable_nat(default_interface);
 376
 377         DBG("tethering started");
 378 }
 379
 380 void __connman_tethering_set_disabled(void)
 381 {
 382         DBG("enabled %d", tethering_enabled - 1);
 383
 384         __connman_dnsproxy_remove_listener(BRIDGE_NAME);
 385
 386         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 387                 return;
 388
 389         disable_nat(default_interface);
 390
 391         dhcp_server_stop(tethering_dhcp_server);
 392
 393         tethering_dhcp_server = NULL;
 394
 395         disable_bridge(BRIDGE_NAME);
 396
 397         remove_bridge(BRIDGE_NAME);
 398
 399         DBG("tethering stopped");
 400 }
 401
 402 void __connman_tethering_update_interface(const char *interface)
 403 {
 404         DBG("interface %s", interface);
 405
 406         g_free(default_interface);
 407
 408         if (interface == NULL) {
 409                 disable_nat(interface);
 410                 default_interface = NULL;
 411
 412                 return;
 413         }
 414
 415         default_interface = g_strdup(interface);
 416
 417         __sync_synchronize();
 418         if (tethering_enabled == 0)
 419                 return;
 420
 421         enable_nat(interface);
 422 }
 423
 424 static void setup_tun_interface(unsigned int flags, unsigned change,
 425                 void *data)
 426 {
 427         struct connman_private_network *pn = data;
 428         unsigned char prefixlen;
 429         DBusMessageIter array, dict;
 430         int err;
 431
 432         DBG("index %d flags %d change %d", pn->index,  flags, change);
 433
 434         if (flags & IFF_UP)
 435                 return;
 436
 437         prefixlen =
 438                 __connman_ipconfig_netmask_prefix_len(PRIVATE_NETWORK_NETMASK);
 439
 440         if ((__connman_inet_modify_address(RTM_NEWADDR,
 441                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 442                                 pn->server_ip, pn->peer_ip,
 443                                 prefixlen, NULL)) < 0) {
 444                 DBG("address setting failed");
 445                 return;
 446         }
 447
 448         connman_inet_ifup(pn->index);
 449
 450         err = enable_nat(default_interface);
 451         if (err < 0) {
 452                 connman_error("failed to enable NAT on %s", default_interface);
 453                 goto error;
 454         }
 455
 456         dbus_message_iter_init_append(pn->reply, &array);
 457
 458         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 459                                                 &pn->path);
 460
 461         connman_dbus_dict_open(&array, &dict);
 462
 463         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 464                                         DBUS_TYPE_STRING, &pn->server_ip);
 465         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 466                                         DBUS_TYPE_STRING, &pn->peer_ip);
 467         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 468                                         DBUS_TYPE_STRING, &pn->primary_dns);
 469         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 470                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 471
 472         connman_dbus_dict_close(&array, &dict);
 473
 474         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 475
 476         g_dbus_send_message(connection, pn->reply);
 477
 478         return;
 479
 480 error:
 481         pn->reply = __connman_error_failed(pn->msg, -err);
 482         g_dbus_send_message(connection, pn->reply);
 483
 484         g_hash_table_remove(pn_hash, pn->path);
 485 }
 486
 487 static void remove_private_network(gpointer user_data)
 488 {
 489         struct connman_private_network *pn = user_data;
 490
 491         disable_nat(default_interface);
 492         connman_rtnl_remove_watch(pn->iface_watch);
 493
 494         if (pn->watch > 0) {
 495                 g_dbus_remove_watch(connection, pn->watch);
 496                 pn->watch = 0;
 497         }
 498
 499         close(pn->fd);
 500
 501         g_free(pn->interface);
 502         g_free(pn->owner);
 503         g_free(pn->path);
 504         g_free(pn);
 505 }
 506
 507 static void owner_disconnect(DBusConnection *connection, void *user_data)
 508 {
 509         struct connman_private_network *pn = user_data;
 510
 511         DBG("%s died", pn->owner);
 512
 513         pn->watch = 0;
 514
 515         g_hash_table_remove(pn_hash, pn->path);
 516 }
 517
 518 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 519 {
 520         struct connman_private_network *pn;
 521         char *iface = NULL;
 522         char *path = NULL;
 523         int index, fd, err;
 524
 525         if (DBUS_TYPE_UNIX_FD < 0)
 526                 return -EINVAL;
 527
 528         fd = connman_inet_create_tunnel(&iface);
 529         if (fd < 0)
 530                 return fd;
 531
 532         path = g_strdup_printf("/tethering/%s", iface);
 533
 534         pn = g_hash_table_lookup(pn_hash, path);
 535         if (pn) {
 536                 g_free(path);
 537                 g_free(iface);
 538                 close(fd);
 539                 return -EEXIST;
 540         }
 541
 542         index = connman_inet_ifindex(iface);
 543         if (index < 0) {
 544                 err = -ENODEV;
 545                 goto error;
 546         }
 547         DBG("interface %s", iface);
 548
 549         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 550
 551         pn = g_try_new0(struct connman_private_network, 1);
 552         if (pn == NULL) {
 553                 err = -ENOMEM;
 554                 goto error;
 555         }
 556
 557         pn->owner = g_strdup(owner);
 558         pn->path = path;
 559         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 560                                         owner_disconnect, pn, NULL);
 561         pn->msg = msg;
 562         pn->reply = dbus_message_new_method_return(pn->msg);
 563         if (pn->reply == NULL)
 564                 goto error;
 565
 566         pn->fd = fd;
 567         pn->interface = iface;
 568         pn->index = index;
 569         pn->server_ip = PRIVATE_NETWORK_IP;
 570         pn->peer_ip = PRIVATE_NETWORK_PEER_IP;
 571         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 572         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 573
 574         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 575                                                 setup_tun_interface, pn);
 576
 577         g_hash_table_insert(pn_hash, pn->path, pn);
 578
 579         return 0;
 580
 581 error:
 582         close(fd);
 583         g_free(iface);
 584         g_free(path);
 585         g_free(pn);
 586         return err;
 587 }
 588
 589 int __connman_private_network_release(const char *path)
 590 {
 591         struct connman_private_network *pn;
 592
 593         pn = g_hash_table_lookup(pn_hash, path);
 594         if (pn == NULL)
 595                 return -EACCES;
 596
 597         g_hash_table_remove(pn_hash, path);
 598         return 0;
 599 }
 600
 601 int __connman_tethering_init(void)
 602 {
 603         DBG("");
 604
 605         tethering_enabled = 0;
 606
 607         connection = connman_dbus_get_connection();
 608         if (connection == NULL)
 609                 return -EFAULT;
 610
 611         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 612                                                 NULL, remove_private_network);
 613
 614         return 0;
 615 }
 616
 617 void __connman_tethering_cleanup(void)
 618 {
 619         DBG("");
 620
 621         __sync_synchronize();
 622         if (tethering_enabled == 0) {
 623                 if (tethering_dhcp_server)
 624                         dhcp_server_stop(tethering_dhcp_server);
 625                 disable_bridge(BRIDGE_NAME);
 626                 remove_bridge(BRIDGE_NAME);
 627         }
 628
 629         if (connection == NULL)
 630                 return;
 631
 632         g_hash_table_destroy(pn_hash);
 633         dbus_connection_unref(connection);
 634 }