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
  68         /* Open registry and look for network adapters */
  69
  70         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
  71                 logger(LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
  72                 return false;
  73         }
  74
  75         for(i = 0; ; i++) {
  76                 len = sizeof(adapterid);
  77
  78                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL)) {
  79                         break;
  80                 }
  81
  82                 /* Find out more about this adapter */
  83
  84                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
  85
  86                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2)) {
  87                         continue;
  88                 }
  89
  90                 len = sizeof(adaptername);
  91                 err = RegQueryValueEx(key2, "Name", 0, 0, adaptername, &len);
  92
  93                 RegCloseKey(key2);
  94
  95                 if(err) {
  96                         continue;
  97                 }
  98
  99                 if(device) {
 100                         if(!strcmp(device, adapterid)) {
 101                                 found = true;
 102                                 break;
 103                         } else {
 104                                 continue;
 105                         }
 106                 }
 107
 108                 if(iface) {
 109                         if(!strcmp(iface, adaptername)) {
 110                                 found = true;
 111                                 break;
 112                         } else {
 113                                 continue;
 114                         }
 115                 }
 116
 117                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 118                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 119
 120                 if(device_handle != INVALID_HANDLE_VALUE) {
 121                         CloseHandle(device_handle);
 122                         found = true;
 123                         break;
 124                 }
 125         }
 126
 127         RegCloseKey(key);
 128
 129         if(!found) {
 130                 logger(LOG_ERR, "No Windows tap device found!");
 131                 return false;
 132         }
 133
 134         if(!device) {
 135                 device = xstrdup(adapterid);
 136         }
 137
 138         if(!iface) {
 139                 iface = xstrdup(adaptername);
 140         }
 141
 142         snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 143
 144         /* Now we are going to open this device twice: once for reading and once for writing.
 145            We do this because apparently it isn't possible to check for activity in the select() loop.
 146            Furthermore I don't really know how to do it the "Windows" way. */
 147
 148         if(socketpair(AF_UNIX, SOCK_DGRAM, PF_UNIX, sp)) {
 149                 logger(LOG_DEBUG, "System call `%s' failed: %s", "socketpair", strerror(errno));
 150                 return false;
 151         }
 152
 153         /* The parent opens the tap device for writing. */
 154
 155         device_handle = CreateFile(tapname, GENERIC_WRITE,  FILE_SHARE_READ,  0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 156
 157         if(device_handle == INVALID_HANDLE_VALUE) {
 158                 logger(LOG_ERR, "Could not open Windows tap device %s (%s) for writing: %s", device, iface, winerror(GetLastError()));
 159                 return false;
 160         }
 161
 162         device_fd = sp[0];
 163
 164         /* Get MAC address from tap device */
 165
 166         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
 167                 logger(LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 168                 return false;
 169         }
 170
 171         if(routing_mode == RMODE_ROUTER) {
 172                 overwrite_mac = 1;
 173         }
 174
 175         /* Now we start the child */
 176
 177         reader_pid = fork();
 178
 179         if(reader_pid == -1) {
 180                 logger(LOG_DEBUG, "System call `%s' failed: %s", "fork", strerror(errno));
 181                 return false;
 182         }
 183
 184         if(!reader_pid) {
 185                 /* The child opens the tap device for reading, blocking.
 186                    It passes everything it reads to the socket. */
 187
 188                 char buf[MTU];
 189                 long lenin;
 190
 191                 CloseHandle(device_handle);
 192
 193                 device_handle = CreateFile(tapname, GENERIC_READ, FILE_SHARE_WRITE, 0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 194
 195                 if(device_handle == INVALID_HANDLE_VALUE) {
 196                         logger(LOG_ERR, "Could not open Windows tap device %s (%s) for reading: %s", device, iface, winerror(GetLastError()));
 197                         buf[0] = 0;
 198                         write(sp[1], buf, 1);
 199                         exit(1);
 200                 }
 201
 202                 logger(LOG_DEBUG, "Tap reader forked and running.");
 203
 204                 /* Notify success */
 205
 206                 buf[0] = 1;
 207                 write(sp[1], buf, 1);
 208
 209                 /* Pass packets */
 210
 211                 for(;;) {
 212                         ReadFile(device_handle, buf, MTU, &lenin, NULL);
 213                         write(sp[1], buf, lenin);
 214                 }
 215         }
 216
 217         read(device_fd, &gelukt, 1);
 218
 219         if(gelukt != 1) {
 220                 logger(LOG_DEBUG, "Tap reader failed!");
 221                 return false;
 222         }
 223
 224         device_info = "Windows tap device";
 225
 226         logger(LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 227
 228         return true;
 229 }
 230
 231 static void close_device(void) {
 232         close(sp[0]);
 233         close(sp[1]);
 234         CloseHandle(device_handle);
 235
 236         kill(reader_pid, SIGKILL);
 237
 238         free(device);
 239         free(iface);
 240 }
 241
 242 static bool read_packet(vpn_packet_t *packet) {
 243         int lenin;
 244
 245         if((lenin = read(sp[0], packet->data, MTU)) <= 0) {
 246                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
 247                        device, strerror(errno));
 248                 return false;
 249         }
 250
 251         packet->len = lenin;
 252
 253         device_total_in += packet->len;
 254
 255         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 256                                 device_info);
 257
 258         return true;
 259 }
 260
 261 static bool write_packet(vpn_packet_t *packet) {
 262         long lenout;
 263
 264         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
 265                                 packet->len, device_info);
 266
 267         if(!WriteFile(device_handle, packet->data, packet->len, &lenout, NULL)) {
 268                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
 269                 return false;
 270         }
 271
 272         device_total_out += packet->len;
 273
 274         return true;
 275 }
 276
 277 static void dump_device_stats(void) {
 278         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
 279         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
 280         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
 281 }
 282
 283 const devops_t os_devops = {
 284         .setup = setup_device,
 285         .close = close_device,
 286         .read = read_packet,
 287         .write = write_packet,
 288         .dump_stats = dump_device_stats,
 289 };