Move AC_GNU_SOURCE up to make autoconf happy.
[tinc] / src / linux / device.c
1 /*
2     device.c -- Interaction with Linux ethertap and tun/tap device
3     Copyright (C) 2001-2005 Ivo Timmermans,
4                   2001-2006 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
17     along with this program; if not, write to the Free Software
18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19
20     $Id$
21 */
22
23 #include "system.h"
24
25 #ifdef HAVE_LINUX_IF_TUN_H
26 #include <linux/if_tun.h>
27 #define DEFAULT_DEVICE "/dev/net/tun"
28 #else
29 #define DEFAULT_DEVICE "/dev/tap0"
30 #endif
31
32 #include "conf.h"
33 #include "logger.h"
34 #include "net.h"
35 #include "route.h"
36 #include "utils.h"
37
38 typedef enum device_type_t {
39         DEVICE_TYPE_ETHERTAP,
40         DEVICE_TYPE_TUN,
41         DEVICE_TYPE_TAP,
42 } device_type_t;
43
44 int device_fd = -1;
45 static device_type_t device_type;
46 char *device;
47 char *iface;
48 char ifrname[IFNAMSIZ];
49 char *device_info;
50
51 static int device_total_in = 0;
52 static int device_total_out = 0;
53
54 bool setup_device(void) {
55         struct ifreq ifr;
56
57         cp();
58
59         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
60                 device = DEFAULT_DEVICE;
61
62         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
63 #ifdef HAVE_LINUX_IF_TUN_H
64                 iface = netname;
65 #else
66                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
67 #endif
68         device_fd = open(device, O_RDWR | O_NONBLOCK);
69
70         if(device_fd < 0) {
71                 logger(LOG_ERR, _("Could not open %s: %s"), device, strerror(errno));
72                 return false;
73         }
74
75 #ifdef HAVE_LINUX_IF_TUN_H
76         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
77
78         memset(&ifr, 0, sizeof(ifr));
79         if(routing_mode == RMODE_ROUTER) {
80                 ifr.ifr_flags = IFF_TUN;
81                 device_type = DEVICE_TYPE_TUN;
82                 device_info = _("Linux tun/tap device (tun mode)");
83         } else {
84                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
85                 device_type = DEVICE_TYPE_TAP;
86                 device_info = _("Linux tun/tap device (tap mode)");
87         }
88
89         if(iface)
90                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
91
92         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
93                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
94                 iface = ifrname;
95         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
96                 logger(LOG_WARNING, _("Old ioctl() request was needed for %s"), device);
97                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
98                 iface = ifrname;
99         } else
100 #endif
101         {
102                 if(routing_mode == RMODE_ROUTER)
103                         overwrite_mac = true;
104                 device_info = _("Linux ethertap device");
105                 device_type = DEVICE_TYPE_ETHERTAP;
106                 iface = rindex(device, '/') ? rindex(device, '/') + 1 : device;
107         }
108
109         logger(LOG_INFO, _("%s is a %s"), device, device_info);
110
111         return true;
112 }
113
114 void close_device(void) {
115         cp();
116         
117         close(device_fd);
118 }
119
120 bool read_packet(vpn_packet_t *packet) {
121         int inlen;
122         
123         cp();
124
125         switch(device_type) {
126                 case DEVICE_TYPE_TUN:
127                         inlen = read(device_fd, packet->data + 10, MTU - 10);
128
129                         if(inlen <= 0) {
130                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
131                                            device_info, device, strerror(errno));
132                                 return false;
133                         }
134
135                         packet->len = inlen + 10;
136                         break;
137                 case DEVICE_TYPE_TAP:
138                         inlen = read(device_fd, packet->data, MTU);
139
140                         if(inlen <= 0) {
141                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
142                                            device_info, device, strerror(errno));
143                                 return false;
144                         }
145
146                         packet->len = inlen;
147                         break;
148                 case DEVICE_TYPE_ETHERTAP:
149                         inlen = read(device_fd, packet->data - 2, MTU + 2);
150
151                         if(inlen <= 0) {
152                                 logger(LOG_ERR, _("Error while reading from %s %s: %s"),
153                                            device_info, device, strerror(errno));
154                                 return false;
155                         }
156
157                         packet->len = inlen - 2;
158                         break;
159         }
160
161         device_total_in += packet->len;
162
163         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Read packet of %d bytes from %s"), packet->len,
164                            device_info);
165
166         return true;
167 }
168
169 bool write_packet(vpn_packet_t *packet) {
170         cp();
171
172         ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Writing packet of %d bytes to %s"),
173                            packet->len, device_info);
174
175         switch(device_type) {
176                 case DEVICE_TYPE_TUN:
177                         packet->data[10] = packet->data[11] = 0;
178                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
179                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
180                                            strerror(errno));
181                                 return false;
182                         }
183                         break;
184                 case DEVICE_TYPE_TAP:
185                         if(write(device_fd, packet->data, packet->len) < 0) {
186                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
187                                            strerror(errno));
188                                 return false;
189                         }
190                         break;
191                 case DEVICE_TYPE_ETHERTAP:
192                         *(short int *)(packet->data - 2) = packet->len;
193
194                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
195                                 logger(LOG_ERR, _("Can't write to %s %s: %s"), device_info, device,
196                                            strerror(errno));
197                                 return false;
198                         }
199                         break;
200         }
201
202         device_total_out += packet->len;
203
204         return true;
205 }
206
207 void dump_device_stats(void) {
208         cp();
209
210         logger(LOG_DEBUG, _("Statistics for %s %s:"), device_info, device);
211         logger(LOG_DEBUG, _(" total bytes in:  %10d"), device_total_in);
212         logger(LOG_DEBUG, _(" total bytes out: %10d"), device_total_out);
213 }