Use IP_DONTFRAGMENT instead of IP_MTU_DISCOVER on Windows.
[tinc] / 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                   2002-2009 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 "logger.h"
28 #include "net.h"
29 #include "route.h"
30 #include "utils.h"
31 #include "xalloc.h"
32
33 #include "mingw/common.h"
34
35 int device_fd = -1;
36 static HANDLE device_handle = INVALID_HANDLE_VALUE;
37 char *device = NULL;
38 char *iface = NULL;
39 static char *device_info = NULL;
40
41 static int device_total_in = 0;
42 static int device_total_out = 0;
43
44 static pid_t reader_pid;
45 static int sp[2];
46
47 bool setup_device(void) {
48         HKEY key, key2;
49         int i, err;
50
51         char regpath[1024];
52         char adapterid[1024];
53         char adaptername[1024];
54         char tapname[1024];
55         char gelukt = 0;
56         long len;
57
58         bool found = false;
59
60         get_config_string(lookup_config(config_tree, "Device"), &device);
61         get_config_string(lookup_config(config_tree, "Interface"), &iface);
62
63         /* Open registry and look for network adapters */
64
65         if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, NETWORK_CONNECTIONS_KEY, 0, KEY_READ, &key)) {
66                 logger(LOG_ERR, "Unable to read registry: %s", winerror(GetLastError()));
67                 return false;
68         }
69
70         for (i = 0; ; i++) {
71                 len = sizeof(adapterid);
72                 if(RegEnumKeyEx(key, i, adapterid, &len, 0, 0, 0, NULL))
73                         break;
74
75                 /* Find out more about this adapter */
76
77                 snprintf(regpath, sizeof(regpath), "%s\\%s\\Connection", NETWORK_CONNECTIONS_KEY, adapterid);
78
79                 if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, regpath, 0, KEY_READ, &key2))
80                         continue;
81
82                 len = sizeof(adaptername);
83                 err = RegQueryValueEx(key2, "Name", 0, 0, adaptername, &len);
84
85                 RegCloseKey(key2);
86
87                 if(err)
88                         continue;
89
90                 if(device) {
91                         if(!strcmp(device, adapterid)) {
92                                 found = true;
93                                 break;
94                         } else
95                                 continue;
96                 }
97
98                 if(iface) {
99                         if(!strcmp(iface, adaptername)) {
100                                 found = true;
101                                 break;
102                         } else
103                                 continue;
104                 }
105
106                 snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, adapterid);
107                 device_handle = CreateFile(tapname, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
108                 if(device_handle != INVALID_HANDLE_VALUE) {
109                         CloseHandle(device_handle);
110                         found = true;
111                         break;
112                 }
113         }
114
115         RegCloseKey(key);
116
117         if(!found) {
118                 logger(LOG_ERR, "No Windows tap device found!");
119                 return false;
120         }
121
122         if(!device)
123                 device = xstrdup(adapterid);
124
125         if(!iface)
126                 iface = xstrdup(adaptername);
127
128         snprintf(tapname, sizeof(tapname), USERMODEDEVICEDIR "%s" TAPSUFFIX, device);
129         
130         /* Now we are going to open this device twice: once for reading and once for writing.
131            We do this because apparently it isn't possible to check for activity in the select() loop.
132            Furthermore I don't really know how to do it the "Windows" way. */
133
134         if(socketpair(AF_UNIX, SOCK_DGRAM, PF_UNIX, sp)) {
135                 logger(LOG_DEBUG, "System call `%s' failed: %s", "socketpair", strerror(errno));
136                 return false;
137         }
138
139         /* The parent opens the tap device for writing. */
140         
141         device_handle = CreateFile(tapname, GENERIC_WRITE,  FILE_SHARE_READ,  0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM , 0);
142         
143         if(device_handle == INVALID_HANDLE_VALUE) {
144                 logger(LOG_ERR, "Could not open Windows tap device %s (%s) for writing: %s", device, iface, winerror(GetLastError()));
145                 return false;
146         }
147
148         device_fd = sp[0];
149
150         /* Get MAC address from tap device */
151
152         if(!DeviceIoControl(device_handle, TAP_IOCTL_GET_MAC, mymac.x, sizeof(mymac.x), mymac.x, sizeof(mymac.x), &len, 0)) {
153                 logger(LOG_ERR, "Could not get MAC address from Windows tap device %s (%s): %s", device, iface, winerror(GetLastError()));
154                 return false;
155         }
156
157         if(routing_mode == RMODE_ROUTER) {
158                 overwrite_mac = 1;
159         }
160
161         /* Now we start the child */
162
163         reader_pid = fork();
164
165         if(reader_pid == -1) {
166                 logger(LOG_DEBUG, "System call `%s' failed: %s", "fork", strerror(errno));
167                 return false;
168         }
169
170         if(!reader_pid) {
171                 /* The child opens the tap device for reading, blocking.
172                    It passes everything it reads to the socket. */
173         
174                 char buf[MTU];
175                 long lenin;
176
177                 CloseHandle(device_handle);
178
179                 device_handle = CreateFile(tapname, GENERIC_READ, FILE_SHARE_WRITE, 0,  OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM, 0);
180
181                 if(device_handle == INVALID_HANDLE_VALUE) {
182                         logger(LOG_ERR, "Could not open Windows tap device %s (%s) for reading: %s", device, iface, winerror(GetLastError()));
183                         buf[0] = 0;
184                         write(sp[1], buf, 1);
185                         exit(1);
186                 }
187
188                 logger(LOG_DEBUG, "Tap reader forked and running.");
189
190                 /* Notify success */
191
192                 buf[0] = 1;
193                 write(sp[1], buf, 1);
194
195                 /* Pass packets */
196
197                 for(;;) {
198                         ReadFile(device_handle, buf, MTU, &lenin, NULL);
199                         write(sp[1], buf, lenin);
200                 }
201         }
202
203         read(device_fd, &gelukt, 1);
204         if(gelukt != 1) {
205                 logger(LOG_DEBUG, "Tap reader failed!");
206                 return false;
207         }
208
209         device_info = "Windows tap device";
210
211         logger(LOG_INFO, "%s (%s) is a %s", device, iface, device_info);
212
213         return true;
214 }
215
216 void close_device(void) {
217         close(sp[0]);
218         close(sp[1]);
219         CloseHandle(device_handle);
220
221         kill(reader_pid, SIGKILL);
222
223         free(device);
224         free(iface);
225 }
226
227 bool read_packet(vpn_packet_t *packet) {
228         int lenin;
229
230         if((lenin = read(sp[0], packet->data, MTU)) <= 0) {
231                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
232                            device, strerror(errno));
233                 return false;
234         }
235         
236         packet->len = lenin;
237
238         device_total_in += packet->len;
239
240         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
241                            device_info);
242
243         return true;
244 }
245
246 bool write_packet(vpn_packet_t *packet) {
247         long lenout;
248
249         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
250                            packet->len, device_info);
251
252         if(!WriteFile (device_handle, packet->data, packet->len, &lenout, NULL)) {
253                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
254                 return false;
255         }
256
257         device_total_out += packet->len;
258
259         return true;
260 }
261
262 void dump_device_stats(void) {
263         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
264         logger(LOG_DEBUG, " total bytes in:  %10d", device_total_in);
265         logger(LOG_DEBUG, " total bytes out: %10d", device_total_out);
266 }