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