www.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                   2002-2016 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 #include "../net.h"
  23
  24 #include <w32api/windows.h>
  25 #include <w32api/winioctl.h>
  26
  27 #include "../conf.h"
  28 #include "../device.h"
  29 #include "../logger.h"
  30 #include "../route.h"
  31 #include "../utils.h"
  32 #include "../xalloc.h"
  33
  34 #include "../mingw/common.h"
  35
  36 int device_fd = -1;
  37 static HANDLE device_handle = INVALID_HANDLE_VALUE;
  38 char *device = NULL;
  39 char *iface = NULL;
  40 static char *device_info = NULL;
  41
  42 static uint64_t device_total_in = 0;
  43 static uint64_t device_total_out = 0;
  44
  45 static pid_t reader_pid;
  46 static int sp[2];
  47
  48 static bool setup_device(void) {
  49         HKEY key, key2;
  50         int i, err;
  51
  52         char regpath[1024];
  53         char adapterid[1024];
  54         char adaptername[1024];
  55         char tapname[1024];
  56         char gelukt = 0;
  57         long len;
  58
  59         bool found = false;
  60
  61         get_config_string(lookup_config(config_tree, "Device"), &device);
  62         get_config_string(lookup_config(config_tree, "Interface"), &iface);
  63
  64         if(device && iface)
  65                 logger(LOG_WARNING, "Warning: both Device and Interface specified, results may not be as expected");
  66
  67         /* Open registry and look for network adapters */
  68
  69         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
  70                 logger(LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
  71                 return false;
  72         }
  73
  74         for (i = 0; ; i++) {
  75                 len = sizeof(adapterid);
  76                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
  77                         break;
  78
  79                 /* Find out more about this adapter */
  80
  81                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
  82
  83                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
  84                         continue;
  85
  86                 len = sizeof(adaptername);
  87                 err = RegQueryValueEx(key2, "Name", 0, 0, adaptername, &len);
  88
  89                 RegCloseKey(key2);
  90
  91                 if(err)
  92                         continue;
  93
  94                 if(device) {
  95                         if(!strcmp(device, adapterid)) {
  96                                 found = true;
  97                                 break;
  98                         } else
  99                                 continue;
 100                 }
 101
 102                 if(iface) {
 103                         if(!strcmp(iface, adaptername)) {
 104                                 found = true;
 105                                 break;
 106                         } else
 107                                 continue;
 108                 }
 109
 110                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 111                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 112                 if(device_handle != INVALID_HANDLE_VALUE) {
 113                         CloseHandle(device_handle);
 114                         found = true;
 115                         break;
 116                 }
 117         }
 118
 119         RegCloseKey(key);
 120
 121         if(!found) {
 122                 logger(LOG_ERR, "No Windows tap device found!");
 123                 return false;
 124         }
 125
 126         if(!device)
 127                 device = xstrdup(adapterid);
 128
 129         if(!iface)
 130                 iface = xstrdup(adaptername);
 131
 132         snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 133
 134         /* Now we are going to open this device twice: once for reading and once for writing.
 135            We do this because apparently it isn't possible to check for activity in the select() loop.
 136            Furthermore I don't really know how to do it the "Windows" way. */
 137
 138         if(socketpair(AF_UNIX, SOCK_DGRAM, PF_UNIX, sp)) {
 139                 logger(LOG_DEBUG, "System call `%s' failed: %s", "socketpair", strerror(errno));
 140                 return false;
 141         }
 142
 143         /* The parent opens the tap device for writing. */
 144
 145         device_handle = CreateFile(tapname, GENERIC_WRITE,  FILE_SHARE_READ,  0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM , 0);
 146
 147         if(device_handle == INVALID_HANDLE_VALUE) {
 148                 logger(LOG_ERR, "Could not open Windows tap device %s (%s) for writing: %s", device, iface, winerror(GetLastError()));
 149                 return false;
 150         }
 151
 152         device_fd = sp[0];
 153
 154         /* Get MAC address from tap device */
 155
 156         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
 157                 logger(LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 158                 return false;
 159         }
 160
 161         if(routing_mode == RMODE_ROUTER) {
 162                 overwrite_mac = 1;
 163         }
 164
 165         /* Now we start the child */
 166
 167         reader_pid = fork();
 168
 169         if(reader_pid == -1) {
 170                 logger(LOG_DEBUG, "System call `%s' failed: %s", "fork", strerror(errno));
 171                 return false;
 172         }
 173
 174         if(!reader_pid) {
 175                 /* The child opens the tap device for reading, blocking.
 176                    It passes everything it reads to the socket. */
 177
 178                 char buf[MTU];
 179                 long lenin;
 180
 181                 CloseHandle(device_handle);
 182
 183                 device_handle = CreateFile(tapname, GENERIC_READ, FILE_SHARE_WRITE, 0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 184
 185                 if(device_handle == INVALID_HANDLE_VALUE) {
 186                         logger(LOG_ERR, "Could not open Windows tap device %s (%s) for reading: %s", device, iface, winerror(GetLastError()));
 187                         buf[0] = 0;
 188                         write(sp[1], buf, 1);
 189                         exit(1);
 190                 }
 191
 192                 logger(LOG_DEBUG, "Tap reader forked and running.");
 193
 194                 /* Notify success */
 195
 196                 buf[0] = 1;
 197                 write(sp[1], buf, 1);
 198
 199                 /* Pass packets */
 200
 201                 for(;;) {
 202                         ReadFile(device_handle, buf, MTU, &lenin, NULL);
 203                         write(sp[1], buf, lenin);
 204                 }
 205         }
 206
 207         read(device_fd, &gelukt, 1);
 208         if(gelukt != 1) {
 209                 logger(LOG_DEBUG, "Tap reader failed!");
 210                 return false;
 211         }
 212
 213         device_info = "Windows tap device";
 214
 215         logger(LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 216
 217         return true;
 218 }
 219
 220 static void close_device(void) {
 221         close(sp[0]);
 222         close(sp[1]);
 223         CloseHandle(device_handle);
 224
 225         kill(reader_pid, SIGKILL);
 226
 227         free(device);
 228         free(iface);
 229 }
 230
 231 static bool read_packet(vpn_packet_t *packet) {
 232         int lenin;
 233
 234         if((lenin = read(sp[0], packet->data, MTU)) <= 0) {
 235                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 236                            device, strerror(errno));
 237                 return false;
 238         }
 239
 240         packet->len = lenin;
 241
 242         device_total_in += packet->len;
 243
 244         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 245                            device_info);
 246
 247         return true;
 248 }
 249
 250 static bool write_packet(vpn_packet_t *packet) {
 251         long lenout;
 252
 253         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 254                            packet->len, device_info);
 255
 256         if(!WriteFile (device_handle, packet->data, packet->len, &lenout, NULL)) {
 257                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
 258                 return false;
 259         }
 260
 261         device_total_out += packet->len;
 262
 263         return true;
 264 }
 265
 266 static void dump_device_stats(void) {
 267         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 268         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 269         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 270 }
 271
 272 const devops_t os_devops = {
 273         .setup = setup_device,
 274         .close = close_device,
 275         .read = read_packet,
 276         .write = write_packet,
 277         .dump_stats = dump_device_stats,
 278 };