Set FD_CLOEXEC flag on all sockets.
[oweals/tinc.git] / src / uml_device.c
1 /*
2     device.c -- UML network socket
3     Copyright (C) 2002-2005 Ivo Timmermans,
4                   2002-2012 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 <sys/un.h>
24
25 #include "conf.h"
26 #include "device.h"
27 #include "net.h"
28 #include "logger.h"
29 #include "utils.h"
30 #include "route.h"
31 #include "xalloc.h"
32
33 static int listen_fd = -1;
34 static int request_fd = -1;
35 static int data_fd = -1;
36 static int write_fd = -1;
37 static int state = 0;
38 static char *device_info;
39
40 extern char *identname;
41 extern volatile bool running;
42
43 static uint64_t device_total_in = 0;
44 static uint64_t device_total_out = 0;
45
46 enum request_type { REQ_NEW_CONTROL };
47
48 static struct request {
49   uint32_t magic;
50   uint32_t version;
51   enum request_type type;
52   struct sockaddr_un sock;
53 } request;
54
55 static struct sockaddr_un data_sun;
56
57 static bool setup_device(void) {
58         struct sockaddr_un listen_sun;
59         static const int one = 1;
60         struct {
61                 char zero;
62                 int pid;
63                 int usecs;
64         } name;
65         struct timeval tv;
66
67         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
68                 xasprintf(&device, LOCALSTATEDIR "/run/%s.umlsocket", identname);
69
70         get_config_string(lookup_config(config_tree, "Interface"), &iface);
71
72         device_info = "UML network socket";
73
74         if((write_fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0) {
75                 logger(LOG_ERR, "Could not open write %s: %s", device_info, strerror(errno));
76                 running = false;
77                 return false;
78         }
79
80 #ifdef FD_CLOEXEC
81         fcntl(write_fd, F_SETFD, FD_CLOEXEC);
82 #endif
83
84         setsockopt(write_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
85
86         if(fcntl(write_fd, F_SETFL, O_NONBLOCK) < 0) {
87                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
88                 running = false;
89                 return false;
90         }
91
92         if((data_fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0) {
93                 logger(LOG_ERR, "Could not open data %s: %s", device_info, strerror(errno));
94                 running = false;
95                 return false;
96         }
97
98 #ifdef FD_CLOEXEC
99         fcntl(data_fd, F_SETFD, FD_CLOEXEC);
100 #endif
101
102         setsockopt(data_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
103
104         if(fcntl(data_fd, F_SETFL, O_NONBLOCK) < 0) {
105                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
106                 running = false;
107                 return false;
108         }
109
110         name.zero = 0;
111         name.pid = getpid();
112         gettimeofday(&tv, NULL);
113         name.usecs = tv.tv_usec;
114         data_sun.sun_family = AF_UNIX;
115         memcpy(&data_sun.sun_path, &name, sizeof name);
116         
117         if(bind(data_fd, (struct sockaddr *)&data_sun, sizeof data_sun) < 0) {
118                 logger(LOG_ERR, "Could not bind data %s: %s", device_info, strerror(errno));
119                 running = false;
120                 return false;
121         }
122
123         if((listen_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
124                 logger(LOG_ERR, "Could not open %s: %s", device_info,
125                            strerror(errno));
126                 return false;
127         }
128
129 #ifdef FD_CLOEXEC
130         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
131 #endif
132
133         setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
134
135         if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
136                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
137                 return false;
138         }
139
140         listen_sun.sun_family = AF_UNIX;
141         strncpy(listen_sun.sun_path, device, sizeof listen_sun.sun_path);
142         if(bind(listen_fd, (struct sockaddr *)&listen_sun, sizeof listen_sun) < 0) {
143                 logger(LOG_ERR, "Could not bind %s to %s: %s", device_info, device, strerror(errno));
144                 return false;
145         }
146
147         if(listen(listen_fd, 1) < 0) {
148                 logger(LOG_ERR, "Could not listen on %s %s: %s", device_info, device, strerror(errno));
149                 return false;
150         }
151
152         device_fd = listen_fd;
153         state = 0;
154
155         logger(LOG_INFO, "%s is a %s", device, device_info);
156
157         if(routing_mode == RMODE_ROUTER)
158                 overwrite_mac = true;
159
160         return true;
161 }
162
163 void close_device(void) {
164         if(listen_fd >= 0)
165                 close(listen_fd);
166
167         if(request_fd >= 0)
168                 close(request_fd);
169
170         if(data_fd >= 0)
171                 close(data_fd);
172
173         if(write_fd >= 0)
174                 close(write_fd);
175
176         unlink(device);
177
178         free(device);
179         if(iface) free(iface);
180 }
181
182 static bool read_packet(vpn_packet_t *packet) {
183         int lenin;
184
185         switch(state) {
186                 case 0: {
187                         struct sockaddr sa;
188                         socklen_t salen = sizeof sa;
189
190                         request_fd = accept(listen_fd, &sa, &salen);
191                         if(request_fd < 0) {
192                                 logger(LOG_ERR, "Could not accept connection to %s %s: %s", device_info, device, strerror(errno));
193                                 return false;
194                         }
195
196 #ifdef FD_CLOEXEC
197                         fcntl(request_fd, F_SETFD, FD_CLOEXEC);
198 #endif
199
200                         if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
201                                 logger(LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
202                                 running = false;
203                                 return false;
204                         }
205
206                         close(listen_fd);
207                         listen_fd = -1;
208                         device_fd = request_fd;
209                         state = 1;
210
211                         return false;
212                 }
213
214                 case 1: {
215                         if((lenin = read(request_fd, &request, sizeof request)) != sizeof request) {
216                                 logger(LOG_ERR, "Error while reading request from %s %s: %s", device_info,
217                                            device, strerror(errno));
218                                 running = false;
219                                 return false;
220                         }
221
222                         if(request.magic != 0xfeedface || request.version != 3 || request.type != REQ_NEW_CONTROL) {
223                                 logger(LOG_ERR, "Unknown magic %x, version %d, request type %d from %s %s",
224                                                 request.magic, request.version, request.type, device_info, device);
225                                 running = false;
226                                 return false;
227                         }
228
229                         if(connect(write_fd, &request.sock, sizeof request.sock) < 0) {
230                                 logger(LOG_ERR, "Could not bind write %s: %s", device_info, strerror(errno));
231                                 running = false;
232                                 return false;
233                         }
234
235                         write(request_fd, &data_sun, sizeof data_sun);
236                         device_fd = data_fd;
237
238                         logger(LOG_INFO, "Connection with UML established");
239
240                         state = 2;
241                         return false;
242                 }
243
244                 case 2: {
245                         if((lenin = read(data_fd, packet->data, MTU)) <= 0) {
246                                 logger(LOG_ERR, "Error while reading from %s %s: %s", device_info,
247                                            device, strerror(errno));
248                                 running = false;
249                                 return false;
250                         }
251
252                         packet->len = lenin;
253
254                         device_total_in += packet->len;
255
256                         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
257                                            device_info);
258
259                         return true;
260                 }
261
262                 default:
263                         logger(LOG_ERR, "Invalid value for state variable in " __FILE__);
264                         abort();
265         }
266 }
267
268 static bool write_packet(vpn_packet_t *packet) {
269         if(state != 2) {
270                 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Dropping packet of %d bytes to %s: not connected to UML yet",
271                                 packet->len, device_info);
272                 return false;
273         }
274
275         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
276                            packet->len, device_info);
277
278         if(write(write_fd, packet->data, packet->len) < 0) {
279                 if(errno != EINTR && errno != EAGAIN) {
280                         logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device, strerror(errno));
281                         running = false;
282                 }
283
284                 return false;
285         }
286
287         device_total_out += packet->len;
288
289         return true;
290 }
291
292 static void dump_device_stats(void) {
293         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
294         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
295         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
296 }
297
298 const devops_t uml_devops = {
299         .setup = setup_device,
300         .close = close_device,
301         .read = read_packet,
302         .write = write_packet,
303         .dump_stats = dump_device_stats,
304 };