Const correctness.
[oweals/tinc.git] / 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 const char *device_info = "Windows tap device";
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         logger(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
234         kill(reader_pid, SIGKILL);
235
236         free(device);
237         free(iface);
238 }
239
240 static bool read_packet(vpn_packet_t *packet) {
241         int lenin;
242
243         if((lenin = read(sp[0], packet->data, MTU)) <= 0) {
244                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
245                        device, strerror(errno));
246                 return false;
247         }
248
249         packet->len = lenin;
250
251         device_total_in += packet->len;
252
253         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
254                                 device_info);
255
256         return true;
257 }
258
259 static bool write_packet(vpn_packet_t *packet) {
260         long lenout;
261
262         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
263                                 packet->len, device_info);
264
265         if(!WriteFile(device_handle, packet->data, packet->len, &lenout, NULL)) {
266                 logger(LOG_ERR, "Error while writing to %s %s: %s", device_info, device, winerror(GetLastError()));
267                 return false;
268         }
269
270         device_total_out += packet->len;
271
272         return true;
273 }
274
275 static void dump_device_stats(void) {
276         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
277         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
278         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
279 }
280
281 const devops_t os_devops = {
282         .setup = setup_device,
283         .close = close_device,
284         .read = read_packet,
285         .write = write_packet,
286         .dump_stats = dump_device_stats,
287 };