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         err = ioctl(sk, SIOCBRADDBR, name);
 214
 215         if (err < 0)
 216                 return -EOPNOTSUPP;
 217
 218         err = set_forward_delay(name, 0);
 219
 220         if (err < 0)
 221                 ioctl(sk, SIOCBRDELBR, name);
 222
 223         close(sk);
 224
 225         return err;
 226 }
 227
 228 static int remove_bridge(const char *name)
 229 {
 230         int sk, err;
 231
 232         DBG("name %s", name);
 233
 234         sk = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
 235         if (sk < 0)
 236                 return -EOPNOTSUPP;
 237
 238         err = ioctl(sk, SIOCBRDELBR, name);
 239
 240         close(sk);
 241
 242         if (err < 0)
 243                 return -EOPNOTSUPP;
 244
 245         return 0;
 246 }
 247
 248 static int enable_bridge(const char *name)
 249 {
 250         int err, index;
 251
 252         index = connman_inet_ifindex(name);
 253         if (index < 0)
 254                 return index;
 255
 256         err = __connman_inet_modify_address(RTM_NEWADDR,
 257                         NLM_F_REPLACE | NLM_F_ACK, index, AF_INET,
 258                                         BRIDGE_IP, NULL, 24, BRIDGE_BCAST);
 259         if (err < 0)
 260                 return err;
 261
 262         return connman_inet_ifup(index);
 263 }
 264
 265 static int disable_bridge(const char *name)
 266 {
 267         int index;
 268
 269         index = connman_inet_ifindex(name);
 270         if (index < 0)
 271                 return index;
 272
 273         return connman_inet_ifdown(index);
 274 }
 275
 276 static int enable_ip_forward(connman_bool_t enable)
 277 {
 278
 279         FILE *f;
 280
 281         f = fopen("/proc/sys/net/ipv4/ip_forward", "r+");
 282         if (f == NULL)
 283                 return -errno;
 284
 285         if (enable == TRUE)
 286                 fprintf(f, "1");
 287         else
 288                 fprintf(f, "0");
 289
 290         fclose(f);
 291
 292         return 0;
 293 }
 294
 295 static int enable_nat(const char *interface)
 296 {
 297         int err;
 298
 299         if (interface == NULL)
 300                 return 0;
 301
 302         /* Enable IPv4 forwarding */
 303         err = enable_ip_forward(TRUE);
 304         if (err < 0)
 305                 return err;
 306
 307         /* POSTROUTING flush */
 308         err = __connman_iptables_command("-t nat -F POSTROUTING");
 309         if (err < 0)
 310                 return err;
 311
 312         /* Enable masquerading */
 313         err = __connman_iptables_command("-t nat -A POSTROUTING "
 314                                         "-o %s -j MASQUERADE", interface);
 315         if (err < 0)
 316                 return err;
 317
 318         return __connman_iptables_commit("nat");
 319 }
 320
 321 static void disable_nat(const char *interface)
 322 {
 323         int err;
 324
 325         /* Disable IPv4 forwarding */
 326         enable_ip_forward(FALSE);
 327
 328         /* POSTROUTING flush */
 329         err = __connman_iptables_command("-t nat -F POSTROUTING");
 330         if (err < 0)
 331                 return;
 332
 333         __connman_iptables_commit("nat");
 334 }
 335
 336 void __connman_tethering_set_enabled(void)
 337 {
 338         int err;
 339         const char *dns;
 340
 341         DBG("enabled %d", tethering_enabled + 1);
 342
 343         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 344                 return;
 345
 346         err = create_bridge(BRIDGE_NAME);
 347         if (err < 0)
 348                 return;
 349
 350         err = enable_bridge(BRIDGE_NAME);
 351         if (err < 0) {
 352                 remove_bridge(BRIDGE_NAME);
 353                 return;
 354         }
 355
 356         dns = BRIDGE_IP;
 357         if (__connman_dnsproxy_add_listener(BRIDGE_NAME) < 0) {
 358                 connman_error("Can't add listener %s to DNS proxy",
 359                                                                 BRIDGE_NAME);
 360                 dns = BRIDGE_DNS;
 361         }
 362
 363         tethering_dhcp_server =
 364                 dhcp_server_start(BRIDGE_NAME,
 365                                         BRIDGE_IP, BRIDGE_SUBNET,
 366                                         BRIDGE_IP_START, BRIDGE_IP_END,
 367                                         24 * 3600, dns);
 368         if (tethering_dhcp_server == NULL) {
 369                 disable_bridge(BRIDGE_NAME);
 370                 remove_bridge(BRIDGE_NAME);
 371                 return;
 372         }
 373
 374         enable_nat(default_interface);
 375
 376         DBG("tethering started");
 377 }
 378
 379 void __connman_tethering_set_disabled(void)
 380 {
 381         DBG("enabled %d", tethering_enabled - 1);
 382
 383         __connman_dnsproxy_remove_listener(BRIDGE_NAME);
 384
 385         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 386                 return;
 387
 388         disable_nat(default_interface);
 389
 390         dhcp_server_stop(tethering_dhcp_server);
 391
 392         disable_bridge(BRIDGE_NAME);
 393
 394         remove_bridge(BRIDGE_NAME);
 395
 396         DBG("tethering stopped");
 397 }
 398
 399 void __connman_tethering_update_interface(const char *interface)
 400 {
 401         DBG("interface %s", interface);
 402
 403         g_free(default_interface);
 404
 405         if (interface == NULL) {
 406                 disable_nat(interface);
 407                 default_interface = NULL;
 408
 409                 return;
 410         }
 411
 412         default_interface = g_strdup(interface);
 413
 414         __sync_synchronize();
 415         if (tethering_enabled == 0)
 416                 return;
 417
 418         enable_nat(interface);
 419 }
 420
 421 static void setup_tun_interface(unsigned int flags, unsigned change,
 422                 void *data)
 423 {
 424         struct connman_private_network *pn = data;
 425         unsigned char prefixlen;
 426         DBusMessageIter array, dict;
 427         int err;
 428
 429         DBG("index %d flags %d change %d", pn->index,  flags, change);
 430
 431         if (flags & IFF_UP)
 432                 return;
 433
 434         prefixlen =
 435                 __connman_ipconfig_netmask_prefix_len(PRIVATE_NETWORK_NETMASK);
 436
 437         if ((__connman_inet_modify_address(RTM_NEWADDR,
 438                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 439                                 pn->server_ip, pn->peer_ip,
 440                                 prefixlen, NULL)) < 0) {
 441                 DBG("address setting failed");
 442                 return;
 443         }
 444
 445         connman_inet_ifup(pn->index);
 446
 447         err = enable_nat(default_interface);
 448         if (err < 0) {
 449                 connman_error("failed to enable NAT on %s", default_interface);
 450                 goto error;
 451         }
 452
 453         dbus_message_iter_init_append(pn->reply, &array);
 454
 455         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 456                                                 &pn->path);
 457
 458         connman_dbus_dict_open(&array, &dict);
 459
 460         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 461                                         DBUS_TYPE_STRING, &pn->server_ip);
 462         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 463                                         DBUS_TYPE_STRING, &pn->peer_ip);
 464         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 465                                         DBUS_TYPE_STRING, &pn->primary_dns);
 466         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 467                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 468
 469         connman_dbus_dict_close(&array, &dict);
 470
 471         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 472
 473         g_dbus_send_message(connection, pn->reply);
 474
 475         return;
 476
 477 error:
 478         pn->reply = __connman_error_failed(pn->msg, -err);
 479         g_dbus_send_message(connection, pn->reply);
 480
 481         g_hash_table_remove(pn_hash, pn->path);
 482 }
 483
 484 static void remove_private_network(gpointer user_data)
 485 {
 486         struct connman_private_network *pn = user_data;
 487
 488         disable_nat(default_interface);
 489         connman_rtnl_remove_watch(pn->iface_watch);
 490
 491         if (pn->watch > 0) {
 492                 g_dbus_remove_watch(connection, pn->watch);
 493                 pn->watch = 0;
 494         }
 495
 496         close(pn->fd);
 497
 498         g_free(pn->interface);
 499         g_free(pn->owner);
 500         g_free(pn->path);
 501         g_free(pn);
 502 }
 503
 504 static void owner_disconnect(DBusConnection *connection, void *user_data)
 505 {
 506         struct connman_private_network *pn = user_data;
 507
 508         DBG("%s died", pn->owner);
 509
 510         pn->watch = 0;
 511
 512         g_hash_table_remove(pn_hash, pn->path);
 513 }
 514
 515 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 516 {
 517         struct connman_private_network *pn;
 518         char *iface = NULL;
 519         char *path = NULL;
 520         int index, fd, err;
 521
 522         if (DBUS_TYPE_UNIX_FD < 0)
 523                 return -EINVAL;
 524
 525         fd = connman_inet_create_tunnel(&iface);
 526         if (fd < 0)
 527                 return fd;
 528
 529         path = g_strdup_printf("/tethering/%s", iface);
 530
 531         pn = g_hash_table_lookup(pn_hash, path);
 532         if (pn) {
 533                 g_free(path);
 534                 g_free(iface);
 535                 close(fd);
 536                 return -EEXIST;
 537         }
 538
 539         index = connman_inet_ifindex(iface);
 540         if (index < 0) {
 541                 err = -ENODEV;
 542                 goto error;
 543         }
 544         DBG("interface %s", iface);
 545
 546         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 547
 548         pn = g_try_new0(struct connman_private_network, 1);
 549         if (pn == NULL) {
 550                 err = -ENOMEM;
 551                 goto error;
 552         }
 553
 554         pn->owner = g_strdup(owner);
 555         pn->path = path;
 556         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 557                                         owner_disconnect, pn, NULL);
 558         pn->msg = msg;
 559         pn->reply = dbus_message_new_method_return(pn->msg);
 560         if (pn->reply == NULL)
 561                 goto error;
 562
 563         pn->fd = fd;
 564         pn->interface = iface;
 565         pn->index = index;
 566         pn->server_ip = PRIVATE_NETWORK_IP;
 567         pn->peer_ip = PRIVATE_NETWORK_PEER_IP;
 568         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 569         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 570
 571         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 572                                                 setup_tun_interface, pn);
 573
 574         g_hash_table_insert(pn_hash, pn->path, pn);
 575
 576         return 0;
 577
 578 error:
 579         close(fd);
 580         g_free(iface);
 581         g_free(path);
 582         g_free(pn);
 583         return err;
 584 }
 585
 586 int __connman_private_network_release(const char *path)
 587 {
 588         struct connman_private_network *pn;
 589
 590         pn = g_hash_table_lookup(pn_hash, path);
 591         if (pn == NULL)
 592                 return -EACCES;
 593
 594         g_hash_table_remove(pn_hash, path);
 595         return 0;
 596 }
 597
 598 int __connman_tethering_init(void)
 599 {
 600         DBG("");
 601
 602         tethering_enabled = 0;
 603
 604         connection = connman_dbus_get_connection();
 605         if (connection == NULL)
 606                 return -EFAULT;
 607
 608         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 609                                                 NULL, remove_private_network);
 610
 611         return 0;
 612 }
 613
 614 void __connman_tethering_cleanup(void)
 615 {
 616         DBG("");
 617
 618         __sync_synchronize();
 619         if (tethering_enabled == 0) {
 620                 if (tethering_dhcp_server)
 621                         dhcp_server_stop(tethering_dhcp_server);
 622                 disable_bridge(BRIDGE_NAME);
 623                 remove_bridge(BRIDGE_NAME);
 624         }
 625
 626         if (connection == NULL)
 627                 return;
 628
 629         g_hash_table_destroy(pn_hash);
 630         dbus_connection_unref(connection);
 631 }