tinc-vpn.org Git - tinc/blob - src/cygwin/device.c

   1 /*
   2     device.c -- Interaction with Windows tap driver in a Cygwin environment
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2014 Guus Sliepen <guus@tinc-vpn.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  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 along
  17     with this program; if not, write to the Free Software Foundation, Inc.,
  18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include "../system.h"
  22
  23 #include <w32api/windows.h>
  24 #include <w32api/winioctl.h>
  25
  26 #include "../conf.h"
  27 #include "../device.h"
  28 #include "../logger.h"
  29 #include "../names.h"
  30 #include "../net.h"
  31 #include "../route.h"
  32 #include "../utils.h"
  33 #include "../xalloc.h"
  34
  35 #include "../mingw/common.h"
  36
  37 int device_fd = -1;
  38 static HANDLE device_handle = INVALID_HANDLE_VALUE;
  39 char *device = NULL;
  40 char *iface = NULL;
  41 static char *device_info = NULL;
  42
  43 static pid_t reader_pid;
  44 static int sp[2];
  45
  46 static bool setup_device(void) {
  47         HKEY key, key2;
  48         int i, err;
  49
  50         char regpath[1024];
  51         char adapterid[1024];
  52         char adaptername[1024];
  53         char tapname[1024];
  54         char gelukt = 0;
  55         long len;
  56
  57         bool found = false;
  58
  59         get_config_string(lookup_config(config_tree, "Device"), &device);
  60         get_config_string(lookup_config(config_tree, "Interface"), &iface);
  61
  62         if(device && interface)
  63                 logger(LOG_WARNING, "Warning: both Device and Interface specified, results may not be as expected");
  64
  65         /* Open registry and look for network adapters */
  66
  67         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
  68                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
  69                 return false;
  70         }
  71
  72         for (i = 0; ; i++) {
  73                 len = sizeof adapterid;
  74                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
  75                         break;
  76
  77                 /* Find out more about this adapter */
  78
  79                 snprintf(regpath, sizeof regpath, "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
  80
  81                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
  82                         continue;
  83
  84                 len = sizeof adaptername;
  85                 err = RegQueryValueEx(key2, "Name", 0, 0, adaptername, &len);
  86
  87                 RegCloseKey(key2);
  88
  89                 if(err)
  90                         continue;
  91
  92                 if(device) {
  93                         if(!strcmp(device, adapterid)) {
  94                                 found = true;
  95                                 break;
  96                         } else
  97                                 continue;
  98                 }
  99
 100                 if(iface) {
 101                         if(!strcmp(iface, adaptername)) {
 102                                 found = true;
 103                                 break;
 104                         } else
 105                                 continue;
 106                 }
 107
 108                 snprintf(tapname, sizeof tapname, USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 109                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 110                 if(device_handle != INVALID_HANDLE_VALUE) {
 111                         CloseHandle(device_handle);
 112                         found = true;
 113                         break;
 114                 }
 115         }
 116
 117         RegCloseKey(key);
 118
 119         if(!found) {
 120                 logger(DEBUG_ALWAYS, LOG_ERR, "No Windows tap device found!");
 121                 return false;
 122         }
 123
 124         if(!device)
 125                 device = xstrdup(adapterid);
 126
 127         if(!iface)
 128                 iface = xstrdup(adaptername);
 129
 130         snprintf(tapname, sizeof tapname, USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 131
 132         /* Now we are going to open this device twice: once for reading and once for writing.
 133            We do this because apparently it isn't possible to check for activity in the select() loop.
 134            Furthermore I don't really know how to do it the "Windows" way. */
 135
 136         if(socketpair(AF_UNIX, SOCK_DGRAM, PF_UNIX, sp)) {
 137                 logger(DEBUG_ALWAYS, LOG_DEBUG, "System call `%s' failed: %s", "socketpair", strerror(errno));
 138                 return false;
 139         }
 140
 141         /* The parent opens the tap device for writing. */
 142
 143         device_handle = CreateFile(tapname, GENERIC_WRITE,  FILE_SHARE_READ,  0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM , 0);
 144
 145         if(device_handle == INVALID_HANDLE_VALUE) {
 146                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open Windows tap device %s (%s) for writing: %s", device, iface, winerror(GetLastError()));
 147                 return false;
 148         }
 149
 150         device_fd = sp[0];
 151
 152         /* Get MAC address from tap device */
 153
 154         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof mymac.x, mymac.x, sizeof mymac.x, &len, 0)) {
 155                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 156                 return false;
 157         }
 158
 159         if(routing_mode == RMODE_ROUTER) {
 160                 overwrite_mac = 1;
 161         }
 162
 163         /* Now we start the child */
 164
 165         reader_pid = fork();
 166
 167         if(reader_pid == -1) {
 168                 logger(DEBUG_ALWAYS, LOG_DEBUG, "System call `%s' failed: %s", "fork", strerror(errno));
 169                 return false;
 170         }
 171
 172         if(!reader_pid) {
 173                 /* The child opens the tap device for reading, blocking.
 174                    It passes everything it reads to the socket. */
 175
 176                 char buf[MTU];
 177                 long inlen;
 178
 179                 CloseHandle(device_handle);
 180
 181                 device_handle = CreateFile(tapname, GENERIC_READ, FILE_SHARE_WRITE, 0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 182
 183                 if(device_handle == INVALID_HANDLE_VALUE) {
 184                         logger(DEBUG_ALWAYS, LOG_ERR, "Could not open Windows tap device %s (%s) for reading: %s", device, iface, winerror(GetLastError()));
 185                         buf[0] = 0;
 186                         write(sp[1], buf, 1);
 187                         exit(1);
 188                 }
 189
 190                 logger(DEBUG_ALWAYS, LOG_DEBUG, "Tap reader forked and running.");
 191
 192                 /* Notify success */
 193
 194                 buf[0] = 1;
 195                 write(sp[1], buf, 1);
 196
 197                 /* Pass packets */
 198
 199                 for(;;) {
 200                         ReadFile(device_handle, buf, MTU, &inlen, NULL);
 201                         write(sp[1], buf, inlen);
 202                 }
 203         }
 204
 205         read(device_fd, &gelukt, 1);
 206         if(gelukt != 1) {
 207                 logger(DEBUG_ALWAYS, LOG_DEBUG, "Tap reader failed!");
 208                 return false;
 209         }
 210
 211         device_info = "Windows tap device";
 212
 213         logger(DEBUG_ALWAYS, LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 214
 215         return true;
 216 }
 217
 218 static void close_device(void) {
 219         close(sp[0]);
 220         close(sp[1]);
 221         CloseHandle(device_handle); device_handle = INVALID_HANDLE_VALUE;
 222
 223         kill(reader_pid, SIGKILL);
 224
 225         free(device); device = NULL;
 226         free(iface); iface = NULL;
 227         device_info = NULL;
 228 }
 229
 230 static bool read_packet(vpn_packet_t *packet) {
 231         int inlen;
 232
 233         if((inlen = read(sp[0], DATA(packet), MTU)) <= 0) {
 234                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 235                            device, strerror(errno));
 236                 return false;
 237         }
 238
 239         packet->len = inlen;
 240
 241         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 242                            device_info);
 243
 244         return true;
 245 }
 246
 247 static bool write_packet(vpn_packet_t *packet) {
 248         long outlen;
 249
 250         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 251                            packet->len, device_info);
 252
 253         if(!WriteFile (device_handle, DATA(packet), packet->len, &outlen, NULL)) {
 254                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
 255                 return false;
 256         }
 257
 258         return true;
 259 }
 260
 261 const devops_t os_devops = {
 262         .setup = setup_device,
 263         .close = close_device,
 264         .read = read_packet,
 265         .write = write_packet,
 266 };