Replace remaining sizeof foo with sizeof(foo).
[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                   2002-2014 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 };