Releasing 1.0.20.
[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                   2001-2012 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 #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 "device.h"
32 #include "logger.h"
33 #include "net.h"
34 #include "route.h"
35 #include "utils.h"
36 #include "xalloc.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 *type = NULL;
49 static char ifrname[IFNAMSIZ];
50 static char *device_info;
51
52 static uint64_t device_total_in = 0;
53 static uint64_t device_total_out = 0;
54
55 static bool setup_device(void) {
56         struct ifreq ifr;
57         bool t1q = false;
58
59         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
60                 device = xstrdup(DEFAULT_DEVICE);
61
62         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
63 #ifdef HAVE_LINUX_IF_TUN_H
64                 if (netname != NULL)
65                         iface = xstrdup(netname);
66 #else
67                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
68 #endif
69         device_fd = open(device, O_RDWR | O_NONBLOCK);
70
71         if(device_fd < 0) {
72                 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
73                 return false;
74         }
75
76 #ifdef FD_CLOEXEC
77         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
78 #endif
79
80 #ifdef HAVE_LINUX_IF_TUN_H
81         /* Ok now check if this is an old ethertap or a new tun/tap thingie */
82
83         memset(&ifr, 0, sizeof(ifr));
84
85         get_config_string(lookup_config(config_tree, "DeviceType"), &type);
86
87         if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
88                 logger(LOG_ERR, "Unknown device type %s!", type);
89                 return false;
90         }
91
92         if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
93                 ifr.ifr_flags = IFF_TUN;
94                 device_type = DEVICE_TYPE_TUN;
95                 device_info = "Linux tun/tap device (tun mode)";
96         } else {
97                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
98                 device_type = DEVICE_TYPE_TAP;
99                 device_info = "Linux tun/tap device (tap mode)";
100         }
101
102 #ifdef IFF_ONE_QUEUE
103         /* Set IFF_ONE_QUEUE flag... */
104         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
105                 ifr.ifr_flags |= IFF_ONE_QUEUE;
106 #endif
107
108         if(iface)
109                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
110
111         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
112                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
113                 if(iface) free(iface);
114                 iface = xstrdup(ifrname);
115         } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
116                 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
117                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
118                 if(iface) free(iface);
119                 iface = xstrdup(ifrname);
120         } else
121 #endif
122         {
123                 if(routing_mode == RMODE_ROUTER)
124                         overwrite_mac = true;
125                 device_info = "Linux ethertap device";
126                 device_type = DEVICE_TYPE_ETHERTAP;
127                 if(iface)
128                         free(iface);
129                 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
130         }
131
132         logger(LOG_INFO, "%s is a %s", device, device_info);
133
134         return true;
135 }
136
137 static void close_device(void) {
138         close(device_fd);
139
140         free(type);
141         free(device);
142         free(iface);
143 }
144
145 static bool read_packet(vpn_packet_t *packet) {
146         int lenin;
147         
148         switch(device_type) {
149                 case DEVICE_TYPE_TUN:
150                         lenin = read(device_fd, packet->data + 10, MTU - 10);
151
152                         if(lenin <= 0) {
153                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
154                                            device_info, device, strerror(errno));
155                                 return false;
156                         }
157
158                         memset(packet->data, 0, 12);
159                         packet->len = lenin + 10;
160                         break;
161                 case DEVICE_TYPE_TAP:
162                         lenin = read(device_fd, packet->data, MTU);
163
164                         if(lenin <= 0) {
165                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
166                                            device_info, device, strerror(errno));
167                                 return false;
168                         }
169
170                         packet->len = lenin;
171                         break;
172                 case DEVICE_TYPE_ETHERTAP:
173                         lenin = read(device_fd, packet->data - 2, MTU + 2);
174
175                         if(lenin <= 0) {
176                                 logger(LOG_ERR, "Error while reading from %s %s: %s",
177                                            device_info, device, strerror(errno));
178                                 return false;
179                         }
180
181                         packet->len = lenin - 2;
182                         break;
183         }
184
185         device_total_in += packet->len;
186
187         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
188                            device_info);
189
190         return true;
191 }
192
193 static bool write_packet(vpn_packet_t *packet) {
194         ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
195                            packet->len, device_info);
196
197         switch(device_type) {
198                 case DEVICE_TYPE_TUN:
199                         packet->data[10] = packet->data[11] = 0;
200                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
201                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
202                                            strerror(errno));
203                                 return false;
204                         }
205                         break;
206                 case DEVICE_TYPE_TAP:
207                         if(write(device_fd, packet->data, packet->len) < 0) {
208                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
209                                            strerror(errno));
210                                 return false;
211                         }
212                         break;
213                 case DEVICE_TYPE_ETHERTAP:
214                         memcpy(packet->data - 2, &packet->len, 2);
215
216                         if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
217                                 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
218                                            strerror(errno));
219                                 return false;
220                         }
221                         break;
222         }
223
224         device_total_out += packet->len;
225
226         return true;
227 }
228
229 static void dump_device_stats(void) {
230         logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
231         logger(LOG_DEBUG, " total bytes in:  %10"PRIu64, device_total_in);
232         logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
233 }
234
235 const devops_t os_devops = {
236         .setup = setup_device,
237         .close = close_device,
238         .read = read_packet,
239         .write = write_packet,
240         .dump_stats = dump_device_stats,
241 };