5fb47718bc094f8ec0d8fa5cf502af8d93f69933
[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                   2001-2009 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 #ifdef HAVE_LINUX_IF_TUN_H
24 #include <linux/if_tun.h>
25 #define DEFAULT_DEVICE "/dev/net/tun"
26 #else
27 #define DEFAULT_DEVICE "/dev/tap0"
28 #endif
29
30 #include "conf.h"
31 #include "logger.h"
32 #include "net.h"
33 #include "route.h"
34 #include "utils.h"
35 #include "xalloc.h"
36 #include "device.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 = NULL;
47 char *iface = NULL;
48 static char ifrname[IFNAMSIZ];
49 static char *device_info;
50
51 uint64_t device_in_packets = 0;
52 uint64_t device_in_bytes = 0;
53 uint64_t device_out_packets = 0;
54 uint64_t device_out_bytes = 0;
55
56 bool setup_device(void) {
57         struct ifreq ifr;
58         bool t1q = false;
59
60         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
61                 device = xstrdup(DEFAULT_DEVICE);
62
63         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
64 #ifdef HAVE_LINUX_IF_TUN_H
65                 if (netname != NULL)
66                         iface = xstrdup(netname);
67 #else
68                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
69 #endif
70         device_fd = open(device, O_RDWR | O_NONBLOCK);
71
72         if(device_fd < 0) {
73                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
74                 return false;
75         }
76
77 #ifdef HAVE_LINUX_IF_TUN_H
78         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
79
80         memset(&ifr, 0, sizeof ifr);
81         if(routing_mode == RMODE_ROUTER) {
82                 ifr.ifr_flags = IFF_TUN;
83                 device_type = DEVICE_TYPE_TUN;
84                 device_info = "Linux tun/tap device (tun mode)";
85         } else {
86                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
87                 device_type = DEVICE_TYPE_TAP;
88                 device_info = "Linux tun/tap device (tap mode)";
89         }
90
91 #ifdef IFF_ONE_QUEUE
92         /* Set IFF_ONE_QUEUE flag... */
93         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
94                 ifr.ifr_flags |= IFF_ONE_QUEUE;
95 #endif
96
97         if(iface)
98                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
99
100         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
101                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
102                 if(iface) free(iface);
103                 iface = xstrdup(ifrname);
104         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
105                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
106                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
107                 if(iface) free(iface);
108                 iface = xstrdup(ifrname);
109         } else
110 #endif
111         {
112                 if(routing_mode == RMODE_ROUTER)
113                         overwrite_mac = true;
114                 device_info = "Linux ethertap device";
115                 device_type = DEVICE_TYPE_ETHERTAP;
116                 if(iface)
117                         free(iface);
118                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
119         }
120
121         logger(LOG_INFO, "%s is a %s", device, device_info);
122
123         return true;
124 }
125
126 void close_device(void) {
127         close(device_fd);
128
129         free(device);
130         free(iface);
131 }
132
133 bool read_packet(vpn_packet_t *packet) {
134         int inlen;
135         
136         switch(device_type) {
137                 case DEVICE_TYPE_TUN:
138                         inlen = read(device_fd, packet->data + 10, MTU - 10);
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 + 10;
147                         break;
148                 case DEVICE_TYPE_TAP:
149                         inlen = read(device_fd, packet->data, MTU);
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;
158                         break;
159                 case DEVICE_TYPE_ETHERTAP:
160                         inlen = read(device_fd, packet->data - 2, MTU + 2);
161
162                         if(inlen <= 0) {
163                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
164                                            device_info, device, strerror(errno));
165                                 return false;
166                         }
167
168                         packet->len = inlen - 2;
169                         break;
170         }
171
172         device_in_packets++;
173         device_in_bytes += packet->len;
174
175         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
176                            device_info);
177
178         return true;
179 }
180
181 bool write_packet(vpn_packet_t *packet) {
182         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
183                            packet->len, device_info);
184
185         switch(device_type) {
186                 case DEVICE_TYPE_TUN:
187                         packet->data[10] = packet->data[11] = 0;
188                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
189                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
190                                            strerror(errno));
191                                 return false;
192                         }
193                         break;
194                 case DEVICE_TYPE_TAP:
195                         if(write(device_fd, packet->data, packet->len) < 0) {
196                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
197                                            strerror(errno));
198                                 return false;
199                         }
200                         break;
201                 case DEVICE_TYPE_ETHERTAP:
202                         *(short int *)(packet->data - 2) = packet->len;
203
204                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
205                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
206                                            strerror(errno));
207                                 return false;
208                         }
209                         break;
210         }
211
212         device_out_packets++;
213         device_out_bytes += packet->len;
214
215         return true;
216 }
217
218 void dump_device_stats(void) {
219         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
220         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
221         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
222 }