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_DNS "8.8.8.8"
  53
  54 #define DEFAULT_MTU     1500
  55
  56 #define PRIVATE_NETWORK_PRIMARY_DNS BRIDGE_DNS
  57 #define PRIVATE_NETWORK_SECONDARY_DNS "8.8.4.4"
  58
  59 static char *default_interface = NULL;
  60 static volatile int tethering_enabled;
  61 static GDHCPServer *tethering_dhcp_server = NULL;
  62 static struct connman_ippool *dhcp_ippool = NULL;
  63 static DBusConnection *connection;
  64 static GHashTable *pn_hash;
  65
  66 struct connman_private_network {
  67         char *owner;
  68         char *path;
  69         guint watch;
  70         DBusMessage *msg;
  71         DBusMessage *reply;
  72         int fd;
  73         char *interface;
  74         int index;
  75         guint iface_watch;
  76         struct connman_ippool *pool;
  77         const char *primary_dns;
  78         const char *secondary_dns;
  79 };
  80
  81 const char *__connman_tethering_get_bridge(void)
  82 {
  83         struct stat st;
  84
  85         if (stat(BRIDGE_PROC_DIR, &st) < 0) {
  86                 connman_error("Missing support for 802.1d ethernet bridging");
  87                 return NULL;
  88         }
  89
  90         return BRIDGE_NAME;
  91 }
  92
  93 static void dhcp_server_debug(const char *str, void *data)
  94 {
  95         connman_info("%s: %s\n", (const char *) data, str);
  96 }
  97
  98 static void dhcp_server_error(GDHCPServerError error)
  99 {
 100         switch (error) {
 101         case G_DHCP_SERVER_ERROR_NONE:
 102                 connman_error("OK");
 103                 break;
 104         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
 105                 connman_error("Interface unavailable");
 106                 break;
 107         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
 108                 connman_error("Interface in use");
 109                 break;
 110         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
 111                 connman_error("Interface down");
 112                 break;
 113         case G_DHCP_SERVER_ERROR_NOMEM:
 114                 connman_error("No memory");
 115                 break;
 116         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
 117                 connman_error("Invalid index");
 118                 break;
 119         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
 120                 connman_error("Invalid option");
 121                 break;
 122         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
 123                 connman_error("Invalid address");
 124                 break;
 125         }
 126 }
 127
 128 static GDHCPServer *dhcp_server_start(const char *bridge,
 129                                 const char *router, const char* subnet,
 130                                 const char *start_ip, const char *end_ip,
 131                                 unsigned int lease_time, const char *dns)
 132 {
 133         GDHCPServerError error;
 134         GDHCPServer *dhcp_server;
 135         int index;
 136
 137         DBG("");
 138
 139         index = connman_inet_ifindex(bridge);
 140         if (index < 0)
 141                 return NULL;
 142
 143         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 144         if (dhcp_server == NULL) {
 145                 dhcp_server_error(error);
 146                 return NULL;
 147         }
 148
 149         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 150
 151         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 152         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 153         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 154         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 155         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 156
 157         g_dhcp_server_start(dhcp_server);
 158
 159         return dhcp_server;
 160 }
 161
 162 static void dhcp_server_stop(GDHCPServer *server)
 163 {
 164         if (server == NULL)
 165                 return;
 166
 167         g_dhcp_server_unref(server);
 168 }
 169
 170 static int set_forward_delay(const char *name, unsigned int delay)
 171 {
 172         FILE *f;
 173         char *forward_delay_path;
 174
 175         forward_delay_path =
 176                 g_strdup_printf("/sys/class/net/%s/bridge/forward_delay", name);
 177
 178         if (forward_delay_path == NULL)
 179                 return -ENOMEM;
 180
 181         f = fopen(forward_delay_path, "r+");
 182
 183         g_free(forward_delay_path);
 184
 185         if (f == NULL)
 186                 return -errno;
 187
 188         fprintf(f, "%d", delay);
 189
 190         fclose(f);
 191
 192         return 0;
 193 }
 194
 195 static int create_bridge(const char *name)
 196 {
 197         int sk, err;
 198
 199         DBG("name %s", name);
 200
 201         sk = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
 202         if (sk < 0)
 203                 return -EOPNOTSUPP;
 204
 205         if (ioctl(sk, SIOCBRADDBR, name) == -1) {
 206                 err = -errno;
 207                 if (err != -EEXIST)
 208                         return -EOPNOTSUPP;
 209         }
 210
 211         err = set_forward_delay(name, 0);
 212
 213         if (err < 0)
 214                 ioctl(sk, SIOCBRDELBR, name);
 215
 216         close(sk);
 217
 218         return err;
 219 }
 220
 221 static int remove_bridge(const char *name)
 222 {
 223         int sk, err;
 224
 225         DBG("name %s", name);
 226
 227         sk = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
 228         if (sk < 0)
 229                 return -EOPNOTSUPP;
 230
 231         err = ioctl(sk, SIOCBRDELBR, name);
 232
 233         close(sk);
 234
 235         if (err < 0)
 236                 return -EOPNOTSUPP;
 237
 238         return 0;
 239 }
 240
 241 static int enable_bridge(const char *name, const char *broadcast,
 242                                 const char *gateway)
 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                                         gateway, NULL, 24, broadcast);
 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 static void tethering_restart(struct connman_ippool *pool, void *user_data)
 331 {
 332         __connman_tethering_set_disabled();
 333         __connman_tethering_set_enabled();
 334 }
 335
 336 void __connman_tethering_set_enabled(void)
 337 {
 338         int index;
 339         int err;
 340         const char *gateway;
 341         const char *broadcast;
 342         const char *subnet_mask;
 343         const char *start_ip;
 344         const char *end_ip;
 345         const char *dns;
 346
 347         DBG("enabled %d", tethering_enabled + 1);
 348
 349         if (__sync_fetch_and_add(&tethering_enabled, 1) != 0)
 350                 return;
 351
 352         err = create_bridge(BRIDGE_NAME);
 353         if (err < 0)
 354                 return;
 355
 356         index = connman_inet_ifindex(BRIDGE_NAME);
 357         dhcp_ippool = __connman_ippool_create(index, 1, 253,
 358                                                 tethering_restart, NULL);
 359         if (dhcp_ippool == NULL) {
 360                 connman_error("Fail to create IP pool");
 361                 return;
 362         }
 363
 364         gateway = __connman_ippool_get_gateway(dhcp_ippool);
 365         broadcast = __connman_ippool_get_broadcast(dhcp_ippool);
 366         subnet_mask = __connman_ippool_get_subnet_mask(dhcp_ippool);
 367         start_ip = __connman_ippool_get_start_ip(dhcp_ippool);
 368         end_ip = __connman_ippool_get_end_ip(dhcp_ippool);
 369
 370         err = enable_bridge(BRIDGE_NAME, gateway, broadcast);
 371         if (err < 0 && err != -EALREADY) {
 372                 remove_bridge(BRIDGE_NAME);
 373                 return;
 374         }
 375
 376         dns = gateway;
 377         if (__connman_dnsproxy_add_listener(BRIDGE_NAME) < 0) {
 378                 connman_error("Can't add listener %s to DNS proxy",
 379                                                                 BRIDGE_NAME);
 380                 dns = BRIDGE_DNS;
 381         }
 382
 383         tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
 384                                                 gateway, subnet_mask,
 385                                                 start_ip, end_ip,
 386                                                 24 * 3600, dns);
 387         if (tethering_dhcp_server == NULL) {
 388                 disable_bridge(BRIDGE_NAME);
 389                 remove_bridge(BRIDGE_NAME);
 390                 return;
 391         }
 392
 393         enable_nat(default_interface);
 394
 395         DBG("tethering started");
 396 }
 397
 398 void __connman_tethering_set_disabled(void)
 399 {
 400         DBG("enabled %d", tethering_enabled - 1);
 401
 402         __connman_dnsproxy_remove_listener(BRIDGE_NAME);
 403
 404         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 405                 return;
 406
 407         disable_nat(default_interface);
 408
 409         dhcp_server_stop(tethering_dhcp_server);
 410
 411         tethering_dhcp_server = NULL;
 412
 413         disable_bridge(BRIDGE_NAME);
 414
 415         __connman_ippool_unref(dhcp_ippool);
 416
 417         remove_bridge(BRIDGE_NAME);
 418
 419         DBG("tethering stopped");
 420 }
 421
 422 void __connman_tethering_update_interface(const char *interface)
 423 {
 424         DBG("interface %s", interface);
 425
 426         g_free(default_interface);
 427
 428         if (interface == NULL) {
 429                 disable_nat(interface);
 430                 default_interface = NULL;
 431
 432                 return;
 433         }
 434
 435         default_interface = g_strdup(interface);
 436
 437         __sync_synchronize();
 438         if (tethering_enabled == 0)
 439                 return;
 440
 441         enable_nat(interface);
 442 }
 443
 444 static void setup_tun_interface(unsigned int flags, unsigned change,
 445                 void *data)
 446 {
 447         struct connman_private_network *pn = data;
 448         unsigned char prefixlen;
 449         DBusMessageIter array, dict;
 450         const char *server_ip;
 451         const char *peer_ip;
 452         const char *subnet_mask;
 453         int err;
 454
 455         DBG("index %d flags %d change %d", pn->index,  flags, change);
 456
 457         if (flags & IFF_UP)
 458                 return;
 459
 460         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 461         server_ip = __connman_ippool_get_start_ip(pn->pool);
 462         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 463         prefixlen =
 464                 __connman_ipconfig_netmask_prefix_len(subnet_mask);
 465
 466         if ((__connman_inet_modify_address(RTM_NEWADDR,
 467                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 468                                 server_ip, peer_ip, prefixlen, NULL)) < 0) {
 469                 DBG("address setting failed");
 470                 return;
 471         }
 472
 473         connman_inet_ifup(pn->index);
 474
 475         err = enable_nat(default_interface);
 476         if (err < 0) {
 477                 connman_error("failed to enable NAT on %s", default_interface);
 478                 goto error;
 479         }
 480
 481         dbus_message_iter_init_append(pn->reply, &array);
 482
 483         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 484                                                 &pn->path);
 485
 486         connman_dbus_dict_open(&array, &dict);
 487
 488         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 489                                         DBUS_TYPE_STRING, &server_ip);
 490         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 491                                         DBUS_TYPE_STRING, &peer_ip);
 492         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 493                                         DBUS_TYPE_STRING, &pn->primary_dns);
 494         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 495                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 496
 497         connman_dbus_dict_close(&array, &dict);
 498
 499         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 500
 501         g_dbus_send_message(connection, pn->reply);
 502
 503         return;
 504
 505 error:
 506         pn->reply = __connman_error_failed(pn->msg, -err);
 507         g_dbus_send_message(connection, pn->reply);
 508
 509         g_hash_table_remove(pn_hash, pn->path);
 510 }
 511
 512 static void remove_private_network(gpointer user_data)
 513 {
 514         struct connman_private_network *pn = user_data;
 515
 516         disable_nat(default_interface);
 517         connman_rtnl_remove_watch(pn->iface_watch);
 518         __connman_ippool_unref(pn->pool);
 519
 520         if (pn->watch > 0) {
 521                 g_dbus_remove_watch(connection, pn->watch);
 522                 pn->watch = 0;
 523         }
 524
 525         close(pn->fd);
 526
 527         g_free(pn->interface);
 528         g_free(pn->owner);
 529         g_free(pn->path);
 530         g_free(pn);
 531 }
 532
 533 static void owner_disconnect(DBusConnection *connection, void *user_data)
 534 {
 535         struct connman_private_network *pn = user_data;
 536
 537         DBG("%s died", pn->owner);
 538
 539         pn->watch = 0;
 540
 541         g_hash_table_remove(pn_hash, pn->path);
 542 }
 543
 544 static void ippool_disconnect(struct connman_ippool *pool, void *user_data)
 545 {
 546         struct connman_private_network *pn = user_data;
 547
 548         DBG("block used externally");
 549
 550         g_hash_table_remove(pn_hash, pn->path);
 551 }
 552
 553 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 554 {
 555         struct connman_private_network *pn;
 556         char *iface = NULL;
 557         char *path = NULL;
 558         int index, fd, err;
 559
 560         if (DBUS_TYPE_UNIX_FD < 0)
 561                 return -EINVAL;
 562
 563         fd = connman_inet_create_tunnel(&iface);
 564         if (fd < 0)
 565                 return fd;
 566
 567         path = g_strdup_printf("/tethering/%s", iface);
 568
 569         pn = g_hash_table_lookup(pn_hash, path);
 570         if (pn) {
 571                 g_free(path);
 572                 g_free(iface);
 573                 close(fd);
 574                 return -EEXIST;
 575         }
 576
 577         index = connman_inet_ifindex(iface);
 578         if (index < 0) {
 579                 err = -ENODEV;
 580                 goto error;
 581         }
 582         DBG("interface %s", iface);
 583
 584         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 585
 586         pn = g_try_new0(struct connman_private_network, 1);
 587         if (pn == NULL) {
 588                 err = -ENOMEM;
 589                 goto error;
 590         }
 591
 592         pn->owner = g_strdup(owner);
 593         pn->path = path;
 594         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 595                                         owner_disconnect, pn, NULL);
 596         pn->msg = msg;
 597         pn->reply = dbus_message_new_method_return(pn->msg);
 598         if (pn->reply == NULL)
 599                 goto error;
 600
 601         pn->fd = fd;
 602         pn->interface = iface;
 603         pn->index = index;
 604         pn->pool = __connman_ippool_create(pn->fd, 1, 1, ippool_disconnect, pn);
 605         if (pn->pool == NULL) {
 606                 errno = -ENOMEM;
 607                 goto error;
 608         }
 609
 610         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 611         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 612
 613         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 614                                                 setup_tun_interface, pn);
 615
 616         g_hash_table_insert(pn_hash, pn->path, pn);
 617
 618         return 0;
 619
 620 error:
 621         close(fd);
 622         g_free(iface);
 623         g_free(path);
 624         g_free(pn);
 625         return err;
 626 }
 627
 628 int __connman_private_network_release(const char *path)
 629 {
 630         struct connman_private_network *pn;
 631
 632         pn = g_hash_table_lookup(pn_hash, path);
 633         if (pn == NULL)
 634                 return -EACCES;
 635
 636         g_hash_table_remove(pn_hash, path);
 637         return 0;
 638 }
 639
 640 int __connman_tethering_init(void)
 641 {
 642         DBG("");
 643
 644         tethering_enabled = 0;
 645
 646         connection = connman_dbus_get_connection();
 647         if (connection == NULL)
 648                 return -EFAULT;
 649
 650         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 651                                                 NULL, remove_private_network);
 652
 653         return 0;
 654 }
 655
 656 void __connman_tethering_cleanup(void)
 657 {
 658         DBG("");
 659
 660         __sync_synchronize();
 661         if (tethering_enabled == 0) {
 662                 if (tethering_dhcp_server)
 663                         dhcp_server_stop(tethering_dhcp_server);
 664                 disable_bridge(BRIDGE_NAME);
 665                 remove_bridge(BRIDGE_NAME);
 666         }
 667
 668         if (connection == NULL)
 669                 return;
 670
 671         g_hash_table_destroy(pn_hash);
 672         dbus_connection_unref(connection);
 673 }