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_PRIMARY_DNS BRIDGE_DNS
  62 #define PRIVATE_NETWORK_SECONDARY_DNS "8.8.4.4"
  63
  64 static char *default_interface = NULL;
  65 static volatile int tethering_enabled;
  66 static GDHCPServer *tethering_dhcp_server = NULL;
  67 static DBusConnection *connection;
  68 static GHashTable *pn_hash;
  69
  70 struct connman_private_network {
  71         char *owner;
  72         char *path;
  73         guint watch;
  74         DBusMessage *msg;
  75         DBusMessage *reply;
  76         int fd;
  77         char *interface;
  78         int index;
  79         guint iface_watch;
  80         struct connman_ippool *pool;
  81         const char *primary_dns;
  82         const char *secondary_dns;
  83 };
  84
  85 const char *__connman_tethering_get_bridge(void)
  86 {
  87         struct stat st;
  88
  89         if (stat(BRIDGE_PROC_DIR, &st) < 0) {
  90                 connman_error("Missing support for 802.1d ethernet bridging");
  91                 return NULL;
  92         }
  93
  94         return BRIDGE_NAME;
  95 }
  96
  97 static void dhcp_server_debug(const char *str, void *data)
  98 {
  99         connman_info("%s: %s\n", (const char *) data, str);
 100 }
 101
 102 static void dhcp_server_error(GDHCPServerError error)
 103 {
 104         switch (error) {
 105         case G_DHCP_SERVER_ERROR_NONE:
 106                 connman_error("OK");
 107                 break;
 108         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
 109                 connman_error("Interface unavailable");
 110                 break;
 111         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
 112                 connman_error("Interface in use");
 113                 break;
 114         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
 115                 connman_error("Interface down");
 116                 break;
 117         case G_DHCP_SERVER_ERROR_NOMEM:
 118                 connman_error("No memory");
 119                 break;
 120         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
 121                 connman_error("Invalid index");
 122                 break;
 123         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 124                 connman_error("Invalid option");
 125                 break;
 126         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 127                 connman_error("Invalid address");
 128                 break;
 129         }
 130 }
 131
 132 static GDHCPServer *dhcp_server_start(const char *bridge,
 133                                 const char *router, const char* subnet,
 134                                 const char *start_ip, const char *end_ip,
 135                                 unsigned int lease_time, const char *dns)
 136 {
 137         GDHCPServerError error;
 138         GDHCPServer *dhcp_server;
 139         int index;
 140
 141         DBG("");
 142
 143         index = connman_inet_ifindex(bridge);
 144         if (index < 0)
 145                 return NULL;
 146
 147         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 148         if (dhcp_server == NULL) {
 149                 dhcp_server_error(error);
 150                 return NULL;
 151         }
 152
 153         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 154
 155         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 156         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 157         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 158         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 159         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 160
 161         g_dhcp_server_start(dhcp_server);
 162
 163         return dhcp_server;
 164 }
 165
 166 static void dhcp_server_stop(GDHCPServer *server)
 167 {
 168         if (server == NULL)
 169                 return;
 170
 171         g_dhcp_server_unref(server);
 172 }
 173
 174 static int set_forward_delay(const char *name, unsigned int delay)
 175 {
 176         FILE *f;
 177         char *forward_delay_path;
 178
 179         forward_delay_path =
 180                 g_strdup_printf("/sys/class/net/%s/bridge/forward_delay", name);
 181
 182         if (forward_delay_path == NULL)
 183                 return -ENOMEM;
 184
 185         f = fopen(forward_delay_path, "r+");
 186
 187         g_free(forward_delay_path);
 188
 189         if (f == NULL)
 190                 return -errno;
 191
 192         fprintf(f, "%d", delay);
 193
 194         fclose(f);
 195
 196         return 0;
 197 }
 198
 199 static int create_bridge(const char *name)
 200 {
 201         int sk, err;
 202
 203         DBG("name %s", name);
 204
 205         sk = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
 206         if (sk < 0)
 207                 return -EOPNOTSUPP;
 208
 209         if (ioctl(sk, SIOCBRADDBR, name) == -1) {
 210                 err = -errno;
 211                 if (err != -EEXIST)
 212                         return -EOPNOTSUPP;
 213         }
 214
 215         err = set_forward_delay(name, 0);
 216
 217         if (err < 0)
 218                 ioctl(sk, SIOCBRDELBR, name);
 219
 220         close(sk);
 221
 222         return err;
 223 }
 224
 225 static int remove_bridge(const char *name)
 226 {
 227         int sk, err;
 228
 229         DBG("name %s", name);
 230
 231         sk = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
 232         if (sk < 0)
 233                 return -EOPNOTSUPP;
 234
 235         err = ioctl(sk, SIOCBRDELBR, name);
 236
 237         close(sk);
 238
 239         if (err < 0)
 240                 return -EOPNOTSUPP;
 241
 242         return 0;
 243 }
 244
 245 static int enable_bridge(const char *name)
 246 {
 247         int err, index;
 248
 249         index = connman_inet_ifindex(name);
 250         if (index < 0)
 251                 return index;
 252
 253         err = __connman_inet_modify_address(RTM_NEWADDR,
 254                         NLM_F_REPLACE | NLM_F_ACK, index, AF_INET,
 255                                         BRIDGE_IP, NULL, 24, BRIDGE_BCAST);
 256         if (err < 0)
 257                 return err;
 258
 259         return connman_inet_ifup(index);
 260 }
 261
 262 static int disable_bridge(const char *name)
 263 {
 264         int index;
 265
 266         index = connman_inet_ifindex(name);
 267         if (index < 0)
 268                 return index;
 269
 270         return connman_inet_ifdown(index);
 271 }
 272
 273 static int enable_ip_forward(connman_bool_t enable)
 274 {
 275
 276         FILE *f;
 277
 278         f = fopen("/proc/sys/net/ipv4/ip_forward", "r+");
 279         if (f == NULL)
 280                 return -errno;
 281
 282         if (enable == TRUE)
 283                 fprintf(f, "1");
 284         else
 285                 fprintf(f, "0");
 286
 287         fclose(f);
 288
 289         return 0;
 290 }
 291
 292 static int enable_nat(const char *interface)
 293 {
 294         int err;
 295
 296         if (interface == NULL)
 297                 return 0;
 298
 299         /* Enable IPv4 forwarding */
 300         err = enable_ip_forward(TRUE);
 301         if (err < 0)
 302                 return err;
 303
 304         /* POSTROUTING flush */
 305         err = __connman_iptables_command("-t nat -F POSTROUTING");
 306         if (err < 0)
 307                 return err;
 308
 309         /* Enable masquerading */
 310         err = __connman_iptables_command("-t nat -A POSTROUTING "
 311                                         "-o %s -j MASQUERADE", interface);
 312         if (err < 0)
 313                 return err;
 314
 315         return __connman_iptables_commit("nat");
 316 }
 317
 318 static void disable_nat(const char *interface)
 319 {
 320         int err;
 321
 322         /* Disable IPv4 forwarding */
 323         enable_ip_forward(FALSE);
 324
 325         /* POSTROUTING flush */
 326         err = __connman_iptables_command("-t nat -F POSTROUTING");
 327         if (err < 0)
 328                 return;
 329
 330         __connman_iptables_commit("nat");
 331 }
 332
 333 void __connman_tethering_set_enabled(void)
 334 {
 335         int err;
 336         const char *dns;
 337
 338         DBG("enabled %d", tethering_enabled + 1);
 339
 340         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 341                 return;
 342
 343         err = create_bridge(BRIDGE_NAME);
 344         if (err < 0)
 345                 return;
 346
 347         err = enable_bridge(BRIDGE_NAME);
 348         if (err < 0 && err != -EALREADY) {
 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 void __connman_tethering_set_disabled(void)
 377 {
 378         DBG("enabled %d", tethering_enabled - 1);
 379
 380         __connman_dnsproxy_remove_listener(BRIDGE_NAME);
 381
 382         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 383                 return;
 384
 385         disable_nat(default_interface);
 386
 387         dhcp_server_stop(tethering_dhcp_server);
 388
 389         tethering_dhcp_server = NULL;
 390
 391         disable_bridge(BRIDGE_NAME);
 392
 393         remove_bridge(BRIDGE_NAME);
 394
 395         DBG("tethering stopped");
 396 }
 397
 398 void __connman_tethering_update_interface(const char *interface)
 399 {
 400         DBG("interface %s", interface);
 401
 402         g_free(default_interface);
 403
 404         if (interface == NULL) {
 405                 disable_nat(interface);
 406                 default_interface = NULL;
 407
 408                 return;
 409         }
 410
 411         default_interface = g_strdup(interface);
 412
 413         __sync_synchronize();
 414         if (tethering_enabled == 0)
 415                 return;
 416
 417         enable_nat(interface);
 418 }
 419
 420 static void setup_tun_interface(unsigned int flags, unsigned change,
 421                 void *data)
 422 {
 423         struct connman_private_network *pn = data;
 424         unsigned char prefixlen;
 425         DBusMessageIter array, dict;
 426         const char *server_ip;
 427         const char *peer_ip;
 428         const char *subnet_mask;
 429         int err;
 430
 431         DBG("index %d flags %d change %d", pn->index,  flags, change);
 432
 433         if (flags & IFF_UP)
 434                 return;
 435
 436         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 437         server_ip = __connman_ippool_get_start_ip(pn->pool);
 438         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 439         prefixlen =
 440                 __connman_ipconfig_netmask_prefix_len(subnet_mask);
 441
 442         if ((__connman_inet_modify_address(RTM_NEWADDR,
 443                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 444                                 server_ip, peer_ip, prefixlen, NULL)) < 0) {
 445                 DBG("address setting failed");
 446                 return;
 447         }
 448
 449         connman_inet_ifup(pn->index);
 450
 451         err = enable_nat(default_interface);
 452         if (err < 0) {
 453                 connman_error("failed to enable NAT on %s", default_interface);
 454                 goto error;
 455         }
 456
 457         dbus_message_iter_init_append(pn->reply, &array);
 458
 459         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 460                                                 &pn->path);
 461
 462         connman_dbus_dict_open(&array, &dict);
 463
 464         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 465                                         DBUS_TYPE_STRING, &server_ip);
 466         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 467                                         DBUS_TYPE_STRING, &peer_ip);
 468         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 469                                         DBUS_TYPE_STRING, &pn->primary_dns);
 470         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 471                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 472
 473         connman_dbus_dict_close(&array, &dict);
 474
 475         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 476
 477         g_dbus_send_message(connection, pn->reply);
 478
 479         return;
 480
 481 error:
 482         pn->reply = __connman_error_failed(pn->msg, -err);
 483         g_dbus_send_message(connection, pn->reply);
 484
 485         g_hash_table_remove(pn_hash, pn->path);
 486 }
 487
 488 static void remove_private_network(gpointer user_data)
 489 {
 490         struct connman_private_network *pn = user_data;
 491
 492         disable_nat(default_interface);
 493         connman_rtnl_remove_watch(pn->iface_watch);
 494         __connman_ippool_unref(pn->pool);
 495
 496         if (pn->watch > 0) {
 497                 g_dbus_remove_watch(connection, pn->watch);
 498                 pn->watch = 0;
 499         }
 500
 501         close(pn->fd);
 502
 503         g_free(pn->interface);
 504         g_free(pn->owner);
 505         g_free(pn->path);
 506         g_free(pn);
 507 }
 508
 509 static void owner_disconnect(DBusConnection *connection, void *user_data)
 510 {
 511         struct connman_private_network *pn = user_data;
 512
 513         DBG("%s died", pn->owner);
 514
 515         pn->watch = 0;
 516
 517         g_hash_table_remove(pn_hash, pn->path);
 518 }
 519
 520 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 521 {
 522         struct connman_private_network *pn;
 523         char *iface = NULL;
 524         char *path = NULL;
 525         int index, fd, err;
 526
 527         if (DBUS_TYPE_UNIX_FD < 0)
 528                 return -EINVAL;
 529
 530         fd = connman_inet_create_tunnel(&iface);
 531         if (fd < 0)
 532                 return fd;
 533
 534         path = g_strdup_printf("/tethering/%s", iface);
 535
 536         pn = g_hash_table_lookup(pn_hash, path);
 537         if (pn) {
 538                 g_free(path);
 539                 g_free(iface);
 540                 close(fd);
 541                 return -EEXIST;
 542         }
 543
 544         index = connman_inet_ifindex(iface);
 545         if (index < 0) {
 546                 err = -ENODEV;
 547                 goto error;
 548         }
 549         DBG("interface %s", iface);
 550
 551         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 552
 553         pn = g_try_new0(struct connman_private_network, 1);
 554         if (pn == NULL) {
 555                 err = -ENOMEM;
 556                 goto error;
 557         }
 558
 559         pn->owner = g_strdup(owner);
 560         pn->path = path;
 561         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 562                                         owner_disconnect, pn, NULL);
 563         pn->msg = msg;
 564         pn->reply = dbus_message_new_method_return(pn->msg);
 565         if (pn->reply == NULL)
 566                 goto error;
 567
 568         pn->fd = fd;
 569         pn->interface = iface;
 570         pn->index = index;
 571         pn->pool = __connman_ippool_create(1, 1);
 572         if (pn->pool == NULL) {
 573                 errno = -ENOMEM;
 574                 goto error;
 575         }
 576
 577         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 578         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 579
 580         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 581                                                 setup_tun_interface, pn);
 582
 583         g_hash_table_insert(pn_hash, pn->path, pn);
 584
 585         return 0;
 586
 587 error:
 588         close(fd);
 589         g_free(iface);
 590         g_free(path);
 591         g_free(pn);
 592         return err;
 593 }
 594
 595 int __connman_private_network_release(const char *path)
 596 {
 597         struct connman_private_network *pn;
 598
 599         pn = g_hash_table_lookup(pn_hash, path);
 600         if (pn == NULL)
 601                 return -EACCES;
 602
 603         g_hash_table_remove(pn_hash, path);
 604         return 0;
 605 }
 606
 607 int __connman_tethering_init(void)
 608 {
 609         DBG("");
 610
 611         tethering_enabled = 0;
 612
 613         connection = connman_dbus_get_connection();
 614         if (connection == NULL)
 615                 return -EFAULT;
 616
 617         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 618                                                 NULL, remove_private_network);
 619
 620         return 0;
 621 }
 622
 623 void __connman_tethering_cleanup(void)
 624 {
 625         DBG("");
 626
 627         __sync_synchronize();
 628         if (tethering_enabled == 0) {
 629                 if (tethering_dhcp_server)
 630                         dhcp_server_stop(tethering_dhcp_server);
 631                 disable_bridge(BRIDGE_NAME);
 632                 remove_bridge(BRIDGE_NAME);
 633         }
 634
 635         if (connection == NULL)
 636                 return;
 637
 638         g_hash_table_destroy(pn_hash);
 639         dbus_connection_unref(connection);
 640 }