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 void __connman_tethering_set_enabled(void)
 331 {
 332         int index;
 333         int err;
 334         const char *gateway;
 335         const char *broadcast;
 336         const char *subnet_mask;
 337         const char *start_ip;
 338         const char *end_ip;
 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         index = connman_inet_ifindex(BRIDGE_NAME);
 351         dhcp_ippool = __connman_ippool_create(index, 1, 253, NULL, NULL);
 352         if (dhcp_ippool == NULL) {
 353                 connman_error("Fail to create IP pool");
 354                 return;
 355         }
 356
 357         gateway = __connman_ippool_get_gateway(dhcp_ippool);
 358         broadcast = __connman_ippool_get_broadcast(dhcp_ippool);
 359         subnet_mask = __connman_ippool_get_subnet_mask(dhcp_ippool);
 360         start_ip = __connman_ippool_get_start_ip(dhcp_ippool);
 361         end_ip = __connman_ippool_get_end_ip(dhcp_ippool);
 362
 363         err = enable_bridge(BRIDGE_NAME, gateway, broadcast);
 364         if (err < 0 && err != -EALREADY) {
 365                 remove_bridge(BRIDGE_NAME);
 366                 return;
 367         }
 368
 369         dns = gateway;
 370         if (__connman_dnsproxy_add_listener(BRIDGE_NAME) < 0) {
 371                 connman_error("Can't add listener %s to DNS proxy",
 372                                                                 BRIDGE_NAME);
 373                 dns = BRIDGE_DNS;
 374         }
 375
 376         tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
 377                                                 gateway, subnet_mask,
 378                                                 start_ip, end_ip,
 379                                                 24 * 3600, dns);
 380         if (tethering_dhcp_server == NULL) {
 381                 disable_bridge(BRIDGE_NAME);
 382                 remove_bridge(BRIDGE_NAME);
 383                 return;
 384         }
 385
 386         enable_nat(default_interface);
 387
 388         DBG("tethering started");
 389 }
 390
 391 void __connman_tethering_set_disabled(void)
 392 {
 393         DBG("enabled %d", tethering_enabled - 1);
 394
 395         __connman_dnsproxy_remove_listener(BRIDGE_NAME);
 396
 397         if (__sync_fetch_and_sub(&tethering_enabled, 1) != 1)
 398                 return;
 399
 400         disable_nat(default_interface);
 401
 402         dhcp_server_stop(tethering_dhcp_server);
 403
 404         tethering_dhcp_server = NULL;
 405
 406         disable_bridge(BRIDGE_NAME);
 407
 408         __connman_ippool_unref(dhcp_ippool);
 409
 410         remove_bridge(BRIDGE_NAME);
 411
 412         DBG("tethering stopped");
 413 }
 414
 415 void __connman_tethering_update_interface(const char *interface)
 416 {
 417         DBG("interface %s", interface);
 418
 419         g_free(default_interface);
 420
 421         if (interface == NULL) {
 422                 disable_nat(interface);
 423                 default_interface = NULL;
 424
 425                 return;
 426         }
 427
 428         default_interface = g_strdup(interface);
 429
 430         __sync_synchronize();
 431         if (tethering_enabled == 0)
 432                 return;
 433
 434         enable_nat(interface);
 435 }
 436
 437 static void setup_tun_interface(unsigned int flags, unsigned change,
 438                 void *data)
 439 {
 440         struct connman_private_network *pn = data;
 441         unsigned char prefixlen;
 442         DBusMessageIter array, dict;
 443         const char *server_ip;
 444         const char *peer_ip;
 445         const char *subnet_mask;
 446         int err;
 447
 448         DBG("index %d flags %d change %d", pn->index,  flags, change);
 449
 450         if (flags & IFF_UP)
 451                 return;
 452
 453         subnet_mask = __connman_ippool_get_subnet_mask(pn->pool);
 454         server_ip = __connman_ippool_get_start_ip(pn->pool);
 455         peer_ip = __connman_ippool_get_end_ip(pn->pool);
 456         prefixlen =
 457                 __connman_ipconfig_netmask_prefix_len(subnet_mask);
 458
 459         if ((__connman_inet_modify_address(RTM_NEWADDR,
 460                                 NLM_F_REPLACE | NLM_F_ACK, pn->index, AF_INET,
 461                                 server_ip, peer_ip, prefixlen, NULL)) < 0) {
 462                 DBG("address setting failed");
 463                 return;
 464         }
 465
 466         connman_inet_ifup(pn->index);
 467
 468         err = enable_nat(default_interface);
 469         if (err < 0) {
 470                 connman_error("failed to enable NAT on %s", default_interface);
 471                 goto error;
 472         }
 473
 474         dbus_message_iter_init_append(pn->reply, &array);
 475
 476         dbus_message_iter_append_basic(&array, DBUS_TYPE_OBJECT_PATH,
 477                                                 &pn->path);
 478
 479         connman_dbus_dict_open(&array, &dict);
 480
 481         connman_dbus_dict_append_basic(&dict, "ServerIPv4",
 482                                         DBUS_TYPE_STRING, &server_ip);
 483         connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 484                                         DBUS_TYPE_STRING, &peer_ip);
 485         connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 486                                         DBUS_TYPE_STRING, &pn->primary_dns);
 487         connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 488                                         DBUS_TYPE_STRING, &pn->secondary_dns);
 489
 490         connman_dbus_dict_close(&array, &dict);
 491
 492         dbus_message_iter_append_basic(&array, DBUS_TYPE_UNIX_FD, &pn->fd);
 493
 494         g_dbus_send_message(connection, pn->reply);
 495
 496         return;
 497
 498 error:
 499         pn->reply = __connman_error_failed(pn->msg, -err);
 500         g_dbus_send_message(connection, pn->reply);
 501
 502         g_hash_table_remove(pn_hash, pn->path);
 503 }
 504
 505 static void remove_private_network(gpointer user_data)
 506 {
 507         struct connman_private_network *pn = user_data;
 508
 509         disable_nat(default_interface);
 510         connman_rtnl_remove_watch(pn->iface_watch);
 511         __connman_ippool_unref(pn->pool);
 512
 513         if (pn->watch > 0) {
 514                 g_dbus_remove_watch(connection, pn->watch);
 515                 pn->watch = 0;
 516         }
 517
 518         close(pn->fd);
 519
 520         g_free(pn->interface);
 521         g_free(pn->owner);
 522         g_free(pn->path);
 523         g_free(pn);
 524 }
 525
 526 static void owner_disconnect(DBusConnection *connection, void *user_data)
 527 {
 528         struct connman_private_network *pn = user_data;
 529
 530         DBG("%s died", pn->owner);
 531
 532         pn->watch = 0;
 533
 534         g_hash_table_remove(pn_hash, pn->path);
 535 }
 536
 537 int __connman_private_network_request(DBusMessage *msg, const char *owner)
 538 {
 539         struct connman_private_network *pn;
 540         char *iface = NULL;
 541         char *path = NULL;
 542         int index, fd, err;
 543
 544         if (DBUS_TYPE_UNIX_FD < 0)
 545                 return -EINVAL;
 546
 547         fd = connman_inet_create_tunnel(&iface);
 548         if (fd < 0)
 549                 return fd;
 550
 551         path = g_strdup_printf("/tethering/%s", iface);
 552
 553         pn = g_hash_table_lookup(pn_hash, path);
 554         if (pn) {
 555                 g_free(path);
 556                 g_free(iface);
 557                 close(fd);
 558                 return -EEXIST;
 559         }
 560
 561         index = connman_inet_ifindex(iface);
 562         if (index < 0) {
 563                 err = -ENODEV;
 564                 goto error;
 565         }
 566         DBG("interface %s", iface);
 567
 568         err = connman_inet_set_mtu(index, DEFAULT_MTU);
 569
 570         pn = g_try_new0(struct connman_private_network, 1);
 571         if (pn == NULL) {
 572                 err = -ENOMEM;
 573                 goto error;
 574         }
 575
 576         pn->owner = g_strdup(owner);
 577         pn->path = path;
 578         pn->watch = g_dbus_add_disconnect_watch(connection, pn->owner,
 579                                         owner_disconnect, pn, NULL);
 580         pn->msg = msg;
 581         pn->reply = dbus_message_new_method_return(pn->msg);
 582         if (pn->reply == NULL)
 583                 goto error;
 584
 585         pn->fd = fd;
 586         pn->interface = iface;
 587         pn->index = index;
 588         pn->pool = __connman_ippool_create(pn->fd, 1, 1, NULL, NULL);
 589         if (pn->pool == NULL) {
 590                 errno = -ENOMEM;
 591                 goto error;
 592         }
 593
 594         pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
 595         pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
 596
 597         pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 598                                                 setup_tun_interface, pn);
 599
 600         g_hash_table_insert(pn_hash, pn->path, pn);
 601
 602         return 0;
 603
 604 error:
 605         close(fd);
 606         g_free(iface);
 607         g_free(path);
 608         g_free(pn);
 609         return err;
 610 }
 611
 612 int __connman_private_network_release(const char *path)
 613 {
 614         struct connman_private_network *pn;
 615
 616         pn = g_hash_table_lookup(pn_hash, path);
 617         if (pn == NULL)
 618                 return -EACCES;
 619
 620         g_hash_table_remove(pn_hash, path);
 621         return 0;
 622 }
 623
 624 int __connman_tethering_init(void)
 625 {
 626         DBG("");
 627
 628         tethering_enabled = 0;
 629
 630         connection = connman_dbus_get_connection();
 631         if (connection == NULL)
 632                 return -EFAULT;
 633
 634         pn_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 635                                                 NULL, remove_private_network);
 636
 637         return 0;
 638 }
 639
 640 void __connman_tethering_cleanup(void)
 641 {
 642         DBG("");
 643
 644         __sync_synchronize();
 645         if (tethering_enabled == 0) {
 646                 if (tethering_dhcp_server)
 647                         dhcp_server_stop(tethering_dhcp_server);
 648                 disable_bridge(BRIDGE_NAME);
 649                 remove_bridge(BRIDGE_NAME);
 650         }
 651
 652         if (connection == NULL)
 653                 return;
 654
 655         g_hash_table_destroy(pn_hash);
 656         dbus_connection_unref(connection);
 657 }