src/tethering.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2010  Intel Corporation. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <unistd.h>
  27 #include <stdio.h>
  28 #include <sys/ioctl.h>
  29 #include <net/if.h>
  30 #include <linux/sockios.h>
  31
  32 #include "connman.h"
  33
  34 #include <gdhcp/gdhcp.h>
  35
  36 #define BRIDGE_NAME "tether"
  37 #define BRIDGE_IP "192.168.218.1"
  38 #define BRIDGE_BCAST "192.168.218.255"
  39 #define BRIDGE_SUBNET "255.255.255.0"
  40 #define BRIDGE_IP_START "192.168.218.100"
  41 #define BRIDGE_IP_END "192.168.218.200"
  42 #define BRIDGE_DNS "8.8.8.8"
  43
  44 static connman_bool_t tethering_status = FALSE;
  45 static char *default_interface = NULL;
  46 static volatile gint tethering_enabled;
  47 static GDHCPServer *tethering_dhcp_server = NULL;
  48
  49 connman_bool_t __connman_tethering_get_status(void)
  50 {
  51         return tethering_status;
  52 }
  53
  54
  55 static void dhcp_server_debug(const char *str, void *data)
  56 {
  57         connman_info("%s: %s\n", (const char *) data, str);
  58 }
  59
  60 static void dhcp_server_error(GDHCPServerError error)
  61 {
  62         switch (error) {
  63         case G_DHCP_SERVER_ERROR_NONE:
  64                 connman_error("OK");
  65                 break;
  66         case G_DHCP_SERVER_ERROR_INTERFACE_UNAVAILABLE:
  67                 connman_error("Interface unavailable");
  68                 break;
  69         case G_DHCP_SERVER_ERROR_INTERFACE_IN_USE:
  70                 connman_error("Interface in use");
  71                 break;
  72         case G_DHCP_SERVER_ERROR_INTERFACE_DOWN:
  73                 connman_error("Interface down");
  74                 break;
  75         case G_DHCP_SERVER_ERROR_NOMEM:
  76                 connman_error("No memory");
  77                 break;
  78         case G_DHCP_SERVER_ERROR_INVALID_INDEX:
  79                 connman_error("Invalid index");
  80                 break;
  81         case G_DHCP_SERVER_ERROR_INVALID_OPTION:
  82                 connman_error("Invalid option");
  83                 break;
  84         case G_DHCP_SERVER_ERROR_IP_ADDRESS_INVALID:
  85                 connman_error("Invalid address");
  86                 break;
  87         }
  88 }
  89
  90 static GDHCPServer *dhcp_server_start(const char *bridge,
  91                                 const char *router, const char* subnet,
  92                                 const char *start_ip, const char *end_ip,
  93                                 unsigned int lease_time, const char *dns)
  94 {
  95         GDHCPServerError error;
  96         GDHCPServer *dhcp_server;
  97         int index;
  98
  99         DBG("");
 100
 101         index = connman_inet_ifindex(bridge);
 102         if (index < 0)
 103                 return NULL;
 104
 105         dhcp_server = g_dhcp_server_new(G_DHCP_IPV4, index, &error);
 106         if (dhcp_server == NULL) {
 107                 dhcp_server_error(error);
 108                 return NULL;
 109         }
 110
 111         g_dhcp_server_set_debug(dhcp_server, dhcp_server_debug, "DHCP server");
 112
 113         g_dhcp_server_set_lease_time(dhcp_server, lease_time);
 114         g_dhcp_server_set_option(dhcp_server, G_DHCP_SUBNET, subnet);
 115         g_dhcp_server_set_option(dhcp_server, G_DHCP_ROUTER, router);
 116         g_dhcp_server_set_option(dhcp_server, G_DHCP_DNS_SERVER, dns);
 117         g_dhcp_server_set_ip_range(dhcp_server, start_ip, end_ip);
 118
 119         g_dhcp_server_start(dhcp_server);
 120
 121         return dhcp_server;
 122 }
 123
 124 static void dhcp_server_stop(GDHCPServer *server)
 125 {
 126         if (server == NULL)
 127                 return;
 128
 129         g_dhcp_server_unref(server);
 130 }
 131
 132 static int create_bridge(const char *name)
 133 {
 134         int sk, err;
 135
 136         DBG("name %s", name);
 137
 138         sk = socket(AF_INET, SOCK_STREAM, 0);
 139         if (sk < 0)
 140                 return -EOPNOTSUPP;
 141
 142         err = ioctl(sk, SIOCBRADDBR, name);
 143
 144         close(sk);
 145
 146         if (err < 0)
 147                 return -EOPNOTSUPP;
 148
 149         return 0;
 150 }
 151
 152 static int remove_bridge(const char *name)
 153 {
 154         int sk, err;
 155
 156         DBG("name %s", name);
 157
 158         sk = socket(AF_INET, SOCK_STREAM, 0);
 159         if (sk < 0)
 160                 return -EOPNOTSUPP;
 161
 162         err = ioctl(sk, SIOCBRDELBR, name);
 163
 164         close(sk);
 165
 166         if (err < 0)
 167                 return -EOPNOTSUPP;
 168
 169         return 0;
 170 }
 171
 172 static int enable_bridge(const char *name)
 173 {
 174         int err, index;
 175
 176         index = connman_inet_ifindex(name);
 177         if (index < 0)
 178                 return index;
 179
 180         err = __connman_inet_modify_address(RTM_NEWADDR,
 181                         NLM_F_REPLACE | NLM_F_ACK, index, AF_INET,
 182                                             BRIDGE_IP, NULL, 24, BRIDGE_BCAST);
 183         if (err < 0)
 184                 return err;
 185
 186         return connman_inet_ifup(index);
 187 }
 188
 189 static int disable_bridge(const char *name)
 190 {
 191         int index;
 192
 193         index = connman_inet_ifindex(name);
 194         if (index < 0)
 195                 return index;
 196
 197         return connman_inet_ifdown(index);
 198 }
 199
 200 static int enable_ip_forward(connman_bool_t enable)
 201 {
 202
 203         FILE *f;
 204
 205         f = fopen("/proc/sys/net/ipv4/ip_forward", "r+");
 206         if (f == NULL)
 207                 return -errno;
 208
 209         if (enable == TRUE)
 210                 fprintf(f, "1");
 211         else
 212                 fprintf(f, "0");
 213
 214         fclose(f);
 215
 216         return 0;
 217 }
 218
 219 static int enable_nat(const char *interface)
 220 {
 221         int err;
 222
 223         if (interface == NULL)
 224                 return 0;
 225
 226         /* Enable IPv4 forwarding */
 227         err = enable_ip_forward(TRUE);
 228         if (err < 0)
 229                 return err;
 230
 231         /* POSTROUTING flush */
 232         err = __connman_iptables_command("-t nat -F POSTROUTING");
 233         if (err < 0)
 234                 return err;
 235
 236         /* Enable masquerading */
 237         err = __connman_iptables_command("-t nat -A POSTROUTING "
 238                                         "-o %s -j MASQUERADE", interface);
 239         if (err < 0)
 240                 return err;
 241
 242         return __connman_iptables_commit("nat");
 243 }
 244
 245 static void disable_nat(const char *interface)
 246 {
 247         int err;
 248
 249         /* Disable IPv4 forwarding */
 250         enable_ip_forward(FALSE);
 251
 252         /* POSTROUTING flush */
 253         err = __connman_iptables_command("-t nat -F POSTROUTING");
 254         if (err < 0)
 255                 return;
 256
 257         __connman_iptables_commit("nat");
 258 }
 259
 260 void __connman_tethering_set_enabled(void)
 261 {
 262         int err;
 263
 264         if (tethering_status == FALSE)
 265                 return;
 266
 267         DBG("enabled %d", tethering_enabled + 1);
 268
 269         if (g_atomic_int_exchange_and_add(&tethering_enabled, 1) == 0) {
 270                 err = enable_bridge(BRIDGE_NAME);
 271                 if (err < 0)
 272                         return;
 273
 274                 tethering_dhcp_server =
 275                         dhcp_server_start(BRIDGE_NAME,
 276                                                 BRIDGE_IP, BRIDGE_SUBNET,
 277                                                 BRIDGE_IP_START, BRIDGE_IP_END,
 278                                                         24 * 3600, BRIDGE_DNS);
 279                 if (tethering_dhcp_server == NULL) {
 280                         disable_bridge(BRIDGE_NAME);
 281                         return;
 282                 }
 283
 284                 enable_nat(default_interface);
 285
 286                 DBG("tethering started");
 287         }
 288 }
 289
 290 void __connman_tethering_set_disabled(void)
 291 {
 292         if (tethering_status == TRUE)
 293                 return;
 294
 295         DBG("enabled %d", tethering_enabled - 1);
 296
 297         if (g_atomic_int_dec_and_test(&tethering_enabled) == 0) {
 298                 disable_nat(default_interface);
 299
 300                 dhcp_server_stop(tethering_dhcp_server);
 301
 302                 disable_bridge(BRIDGE_NAME);
 303
 304                 DBG("tethering stopped");
 305         }
 306 }
 307
 308 int __connman_tethering_set_status(connman_bool_t status)
 309 {
 310         if (status == tethering_status)
 311                 return -EALREADY;
 312
 313         if (status == TRUE) {
 314                 create_bridge(BRIDGE_NAME);
 315                 __connman_technology_enable_tethering(BRIDGE_NAME);
 316         } else {
 317                 __connman_technology_disable_tethering(BRIDGE_NAME);
 318                 remove_bridge(BRIDGE_NAME);
 319         }
 320
 321         tethering_status = status;
 322
 323         return 0;
 324 }
 325
 326 void __connman_tethering_update_interface(const char *interface)
 327 {
 328         DBG("interface %s", interface);
 329
 330         g_free(default_interface);
 331
 332         if (interface == NULL) {
 333                 disable_nat(interface);
 334
 335                 return;
 336         }
 337
 338         default_interface = g_strdup(interface);
 339
 340         if (tethering_status == FALSE ||
 341                         !g_atomic_int_get(&tethering_enabled))
 342                 return;
 343
 344         enable_nat(interface);
 345 }
 346
 347 int __connman_tethering_init(void)
 348 {
 349         DBG("");
 350
 351         tethering_enabled = 0;
 352
 353         return 0;
 354 }
 355
 356 void __connman_tethering_cleanup(void)
 357 {
 358         DBG("");
 359
 360         if (tethering_status == TRUE) {
 361                 if (tethering_dhcp_server)
 362                         dhcp_server_stop(tethering_dhcp_server);
 363                 disable_bridge(BRIDGE_NAME);
 364                 remove_bridge(BRIDGE_NAME);
 365         }
 366 }