Prefer ncurses over curses.
[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                   2001-2013 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 <linux/if_tun.h>
24 #define DEFAULT_DEVICE "/dev/net/tun"
25
26 #include "../conf.h"
27 #include "../device.h"
28 #include "../logger.h"
29 #include "../names.h"
30 #include "../net.h"
31 #include "../route.h"
32 #include "../utils.h"
33 #include "../xalloc.h"
34 #include "../device.h"
35
36 typedef enum device_type_t {
37         DEVICE_TYPE_TUN,
38         DEVICE_TYPE_TAP,
39 } device_type_t;
40
41 int device_fd = -1;
42 static device_type_t device_type;
43 char *device = NULL;
44 char *iface = NULL;
45 static char *type = NULL;
46 static char ifrname[IFNAMSIZ];
47 static char *device_info;
48
49 uint64_t device_in_packets = 0;
50 uint64_t device_in_bytes = 0;
51 uint64_t device_out_packets = 0;
52 uint64_t device_out_bytes = 0;
53
54 static bool setup_device(void) {
55         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
56                 device = xstrdup(DEFAULT_DEVICE);
57
58         if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
59                 if(netname)
60                         iface = xstrdup(netname);
61
62         device_fd = open(device, O_RDWR | O_NONBLOCK);
63
64         if(device_fd < 0) {
65                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open %s: %s", device, strerror(errno));
66                 return false;
67         }
68
69 #ifdef FD_CLOEXEC
70         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
71 #endif
72
73         struct ifreq ifr = {{{0}}};
74
75         get_config_string(lookup_config(config_tree, "DeviceType"), &type);
76
77         if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
78                 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown device type %s!", type);
79                 return false;
80         }
81
82         if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
83                 ifr.ifr_flags = IFF_TUN;
84                 device_type = DEVICE_TYPE_TUN;
85                 device_info = "Linux tun/tap device (tun mode)";
86         } else {
87                 if (routing_mode == RMODE_ROUTER)
88                         overwrite_mac = true;
89                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
90                 device_type = DEVICE_TYPE_TAP;
91                 device_info = "Linux tun/tap device (tap mode)";
92         }
93
94 #ifdef IFF_ONE_QUEUE
95         /* Set IFF_ONE_QUEUE flag... */
96
97         bool t1q = false;
98         if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
99                 ifr.ifr_flags |= IFF_ONE_QUEUE;
100 #endif
101
102         if(iface)
103                 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
104
105         if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
106                 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
107                 free(iface);
108                 iface = xstrdup(ifrname);
109         }
110
111         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
112
113         return true;
114 }
115
116 static void close_device(void) {
117         close(device_fd);
118
119         free(type);
120         free(device);
121         free(iface);
122 }
123
124 static bool read_packet(vpn_packet_t *packet) {
125         int inlen;
126
127         switch(device_type) {
128                 case DEVICE_TYPE_TUN:
129                         inlen = read(device_fd, packet->data + 10, MTU - 10);
130
131                         if(inlen <= 0) {
132                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s",
133                                            device_info, device, strerror(errno));
134                                 return false;
135                         }
136
137                         memset(packet->data, 0, 12);
138                         packet->len = inlen + 10;
139                         break;
140                 case DEVICE_TYPE_TAP:
141                         inlen = read(device_fd, packet->data, MTU);
142
143                         if(inlen <= 0) {
144                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s",
145                                            device_info, device, strerror(errno));
146                                 return false;
147                         }
148
149                         packet->len = inlen;
150                         break;
151                 default:
152                         abort();
153         }
154
155         device_in_packets++;
156         device_in_bytes += packet->len;
157
158         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
159                            device_info);
160
161         return true;
162 }
163
164 static bool write_packet(vpn_packet_t *packet) {
165         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
166                            packet->len, device_info);
167
168         switch(device_type) {
169                 case DEVICE_TYPE_TUN:
170                         packet->data[10] = packet->data[11] = 0;
171                         if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
172                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
173                                            strerror(errno));
174                                 return false;
175                         }
176                         break;
177                 case DEVICE_TYPE_TAP:
178                         if(write(device_fd, packet->data, packet->len) < 0) {
179                                 logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device,
180                                            strerror(errno));
181                                 return false;
182                         }
183                         break;
184                 default:
185                         abort();
186         }
187
188         device_out_packets++;
189         device_out_bytes += packet->len;
190
191         return true;
192 }
193
194 static void dump_device_stats(void) {
195         logger(DEBUG_ALWAYS, LOG_DEBUG, "Statistics for %s %s:", device_info, device);
196         logger(DEBUG_ALWAYS, LOG_DEBUG, " total bytes in:  %10"PRIu64, device_in_bytes);
197         logger(DEBUG_ALWAYS, LOG_DEBUG, " total bytes out: %10"PRIu64, device_out_bytes);
198 }
199
200 const devops_t os_devops = {
201         .setup = setup_device,
202         .close = close_device,
203         .read = read_packet,
204         .write = write_packet,
205         .dump_stats = dump_device_stats,
206 };