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 #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 "../names.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 && iface) {
  63                 logger(LOG_WARNING, "Warning: both Device and Interface specified, results may not be as expected");
  64         }
  65
  66         /* Open registry and look for network adapters */
  67
  68         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
  69                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
  70                 return false;
  71         }
  72
  73         for(i = 0; ; i++) {
  74                 len = sizeof(adapterid);
  75
  76                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL)) {
  77                         break;
  78                 }
  79
  80                 /* Find out more about this adapter */
  81
  82                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
  83
  84                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2)) {
  85                         continue;
  86                 }
  87
  88                 len = sizeof(adaptername);
  89                 err = RegQueryValueEx(key2, "Name", 0, 0, adaptername, &len);
  90
  91                 RegCloseKey(key2);
  92
  93                 if(err) {
  94                         continue;
  95                 }
  96
  97                 if(device) {
  98                         if(!strcmp(device, adapterid)) {
  99                                 found = true;
 100                                 break;
 101                         } else {
 102                                 continue;
 103                         }
 104                 }
 105
 106                 if(iface) {
 107                         if(!strcmp(iface, adaptername)) {
 108                                 found = true;
 109                                 break;
 110                         } else {
 111                                 continue;
 112                         }
 113                 }
 114
 115                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 116                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 117
 118                 if(device_handle != INVALID_HANDLE_VALUE) {
 119                         CloseHandle(device_handle);
 120                         found = true;
 121                         break;
 122                 }
 123         }
 124
 125         RegCloseKey(key);
 126
 127         if(!found) {
 128                 logger(DEBUG_ALWAYS, LOG_ERR, "No Windows tap device found!");
 129                 return false;
 130         }
 131
 132         if(!device) {
 133                 device = xstrdup(adapterid);
 134         }
 135
 136         if(!iface) {
 137                 iface = xstrdup(adaptername);
 138         }
 139
 140         snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 141
 142         /* Now we are going to open this device twice: once for reading and once for writing.
 143            We do this because apparently it isn't possible to check for activity in the select() loop.
 144            Furthermore I don't really know how to do it the "Windows" way. */
 145
 146         if(socketpair(AF_UNIX, SOCK_DGRAM, PF_UNIX, sp)) {
 147                 logger(DEBUG_ALWAYS, LOG_DEBUG, "System call `%s' failed: %s", "socketpair", strerror(errno));
 148                 return false;
 149         }
 150
 151         /* The parent opens the tap device for writing. */
 152
 153         device_handle = CreateFile(tapname, GENERIC_WRITE,  FILE_SHARE_READ,  0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 154
 155         if(device_handle == INVALID_HANDLE_VALUE) {
 156                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open Windows tap device %s (%s) for writing: %s", device, iface, winerror(GetLastError()));
 157                 return false;
 158         }
 159
 160         device_fd = sp[0];
 161
 162         /* Get MAC address from tap device */
 163
 164         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof mymac.x, &len, 0)) {
 165                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 166                 return false;
 167         }
 168
 169         if(routing_mode == RMODE_ROUTER) {
 170                 overwrite_mac = 1;
 171         }
 172
 173         /* Now we start the child */
 174
 175         reader_pid = fork();
 176
 177         if(reader_pid == -1) {
 178                 logger(DEBUG_ALWAYS, LOG_DEBUG, "System call `%s' failed: %s", "fork", strerror(errno));
 179                 return false;
 180         }
 181
 182         if(!reader_pid) {
 183                 /* The child opens the tap device for reading, blocking.
 184                    It passes everything it reads to the socket. */
 185
 186                 char buf[MTU];
 187                 long inlen;
 188
 189                 CloseHandle(device_handle);
 190
 191                 device_handle = CreateFile(tapname, GENERIC_READ, FILE_SHARE_WRITE, 0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 192
 193                 if(device_handle == INVALID_HANDLE_VALUE) {
 194                         logger(DEBUG_ALWAYS, LOG_ERR, "Could not open Windows tap device %s (%s) for reading: %s", device, iface, winerror(GetLastError()));
 195                         buf[0] = 0;
 196                         write(sp[1], buf, 1);
 197                         exit(1);
 198                 }
 199
 200                 logger(DEBUG_ALWAYS, LOG_DEBUG, "Tap reader forked and running.");
 201
 202                 /* Notify success */
 203
 204                 buf[0] = 1;
 205                 write(sp[1], buf, 1);
 206
 207                 /* Pass packets */
 208
 209                 for(;;) {
 210                         ReadFile(device_handle, buf, MTU, &inlen, NULL);
 211                         write(sp[1], buf, inlen);
 212                 }
 213         }
 214
 215         read(device_fd, &gelukt, 1);
 216
 217         if(gelukt != 1) {
 218                 logger(DEBUG_ALWAYS, LOG_DEBUG, "Tap reader failed!");
 219                 return false;
 220         }
 221
 222         device_info = "Windows tap device";
 223
 224         logger(DEBUG_ALWAYS, LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 225
 226         return true;
 227 }
 228
 229 static void close_device(void) {
 230         close(sp[0]);
 231         close(sp[1]);
 232         CloseHandle(device_handle);
 233         device_handle = INVALID_HANDLE_VALUE;
 234
 235         kill(reader_pid, SIGKILL);
 236
 237         free(device);
 238         device = NULL;
 239         free(iface);
 240         iface = NULL;
 241         device_info = NULL;
 242 }
 243
 244 static bool read_packet(vpn_packet_t *packet) {
 245         int inlen;
 246
 247         if((inlen = read(sp[0], DATA(packet), MTU)) <= 0) {
 248                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 249                        device, strerror(errno));
 250                 return false;
 251         }
 252
 253         packet->len = inlen;
 254
 255         logger(DEBUG_TRAFFIC, 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 outlen;
 263
 264         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 265                packet->len, device_info);
 266
 267         if(!WriteFile(device_handle, DATA(packet), packet->len, &outlen, NULL)) {
 268                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
 269                 return false;
 270         }
 271
 272         return true;
 273 }
 274
 275 const devops_t os_devops = {
 276         .setup = setup_device,
 277         .close = close_device,
 278         .read = read_packet,
 279         .write = write_packet,
 280 };