git.meshlink.io Git - meshlink/blob - cygwin/device.c

   1 /*
   2     device.c -- Interaction with Windows tap driver in a Cygwin environment
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2013 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         /* Open registry and look for network adapters */
  63
  64         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
  65                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
  66                 return false;
  67         }
  68
  69         for (i = 0; ; i++) {
  70                 len = sizeof adapterid;
  71                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
  72                         break;
  73
  74                 /* Find out more about this adapter */
  75
  76                 snprintf(regpath, sizeof regpath, "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
  77
  78                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
  79                         continue;
  80
  81                 len = sizeof adaptername;
  82                 err = RegQueryValueEx(key2, "Name", 0, 0, adaptername, &len);
  83
  84                 RegCloseKey(key2);
  85
  86                 if(err)
  87                         continue;
  88
  89                 if(device) {
  90                         if(!strcmp(device, adapterid)) {
  91                                 found = true;
  92                                 break;
  93                         } else
  94                                 continue;
  95                 }
  96
  97                 if(iface) {
  98                         if(!strcmp(iface, adaptername)) {
  99                                 found = true;
 100                                 break;
 101                         } else
 102                                 continue;
 103                 }
 104
 105                 snprintf(tapname, sizeof tapname, USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
 106                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 107                 if(device_handle != INVALID_HANDLE_VALUE) {
 108                         CloseHandle(device_handle);
 109                         found = true;
 110                         break;
 111                 }
 112         }
 113
 114         RegCloseKey(key);
 115
 116         if(!found) {
 117                 logger(DEBUG_ALWAYS, LOG_ERR, "No Windows tap device found!");
 118                 return false;
 119         }
 120
 121         if(!device)
 122                 device = xstrdup(adapterid);
 123
 124         if(!iface)
 125                 iface = xstrdup(adaptername);
 126
 127         snprintf(tapname, sizeof tapname, USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
 128
 129         /* Now we are going to open this device twice: once for reading and once for writing.
 130            We do this because apparently it isn't possible to check for activity in the select() loop.
 131            Furthermore I don't really know how to do it the "Windows" way. */
 132
 133         if(socketpair(AF_UNIX, SOCK_DGRAM, PF_UNIX, sp)) {
 134                 logger(DEBUG_ALWAYS, LOG_DEBUG, "System call `%s' failed: %s", "socketpair", strerror(errno));
 135                 return false;
 136         }
 137
 138         /* The parent opens the tap device for writing. */
 139
 140         device_handle = CreateFile(tapname, GENERIC_WRITE,  FILE_SHARE_READ,  0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM , 0);
 141
 142         if(device_handle == INVALID_HANDLE_VALUE) {
 143                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open Windows tap device %s (%s) for writing: %s", device, iface, winerror(GetLastError()));
 144                 return false;
 145         }
 146
 147         device_fd = sp[0];
 148
 149         /* Get MAC address from tap device */
 150
 151         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof mymac.x, mymac.x, sizeof mymac.x, &len, 0)) {
 152                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
 153                 return false;
 154         }
 155
 156         if(routing_mode == RMODE_ROUTER) {
 157                 overwrite_mac = 1;
 158         }
 159
 160         /* Now we start the child */
 161
 162         reader_pid = fork();
 163
 164         if(reader_pid == -1) {
 165                 logger(DEBUG_ALWAYS, LOG_DEBUG, "System call `%s' failed: %s", "fork", strerror(errno));
 166                 return false;
 167         }
 168
 169         if(!reader_pid) {
 170                 /* The child opens the tap device for reading, blocking.
 171                    It passes everything it reads to the socket. */
 172
 173                 char buf[MTU];
 174                 long inlen;
 175
 176                 CloseHandle(device_handle);
 177
 178                 device_handle = CreateFile(tapname, GENERIC_READ, FILE_SHARE_WRITE, 0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
 179
 180                 if(device_handle == INVALID_HANDLE_VALUE) {
 181                         logger(DEBUG_ALWAYS, LOG_ERR, "Could not open Windows tap device %s (%s) for reading: %s", device, iface, winerror(GetLastError()));
 182                         buf[0] = 0;
 183                         write(sp[1], buf, 1);
 184                         exit(1);
 185                 }
 186
 187                 logger(DEBUG_ALWAYS, LOG_DEBUG, "Tap reader forked and running.");
 188
 189                 /* Notify success */
 190
 191                 buf[0] = 1;
 192                 write(sp[1], buf, 1);
 193
 194                 /* Pass packets */
 195
 196                 for(;;) {
 197                         ReadFile(device_handle, buf, MTU, &inlen, NULL);
 198                         write(sp[1], buf, inlen);
 199                 }
 200         }
 201
 202         read(device_fd, &gelukt, 1);
 203         if(gelukt != 1) {
 204                 logger(DEBUG_ALWAYS, LOG_DEBUG, "Tap reader failed!");
 205                 return false;
 206         }
 207
 208         device_info = "Windows tap device";
 209
 210         logger(DEBUG_ALWAYS, LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
 211
 212         return true;
 213 }
 214
 215 static void close_device(void) {
 216         close(sp[0]);
 217         close(sp[1]);
 218         CloseHandle(device_handle);
 219
 220         kill(reader_pid, SIGKILL);
 221
 222         free(device);
 223         free(iface);
 224 }
 225
 226 static bool read_packet(vpn_packet_t *packet) {
 227         int inlen;
 228
 229         if((inlen = read(sp[0], packet->data, MTU)) <= 0) {
 230                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 231                            device, strerror(errno));
 232                 return false;
 233         }
 234
 235         packet->len = inlen;
 236
 237         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 238                            device_info);
 239
 240         return true;
 241 }
 242
 243 static bool write_packet(vpn_packet_t *packet) {
 244         long outlen;
 245
 246         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 247                            packet->len, device_info);
 248
 249         if(!WriteFile (device_handle, packet->data, packet->len, &outlen, NULL)) {
 250                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
 251                 return false;
 252         }
 253
 254         return true;
 255 }
 256
 257 const devops_t os_devops = {
 258         .setup = setup_device,
 259         .close = close_device,
 260         .read = read_packet,
 261         .write = write_packet,
 262 };