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