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>
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.
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.
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.
23 #ifdef HAVE_LINUX_IF_TUN_H
24 #include <linux/if_tun.h>
25 #define DEFAULT_DEVICE "/dev/net/tun"
27 #define DEFAULT_DEVICE "/dev/tap0"
38 typedef enum device_type_t {
45 static device_type_t device_type;
48 static char ifrname[IFNAMSIZ];
49 static char *device_info;
51 static uint64_t device_total_in = 0;
52 static uint64_t device_total_out = 0;
54 static bool setup_device(void) {
58 if(!get_config_string(lookup_config(config_tree, "Device"), &device))
59 device = xstrdup(DEFAULT_DEVICE);
61 if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
62 #ifdef HAVE_LINUX_IF_TUN_H
64 iface = xstrdup(netname);
66 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
68 device_fd = open(device, O_RDWR | O_NONBLOCK);
71 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
76 fcntl(device_fd, F_SETFD, FD_CLOEXEC);
79 #ifdef HAVE_LINUX_IF_TUN_H
80 /* Ok now check if this is an old ethertap or a new tun/tap thingie */
82 memset(&ifr, 0, sizeof(ifr));
83 if(routing_mode == RMODE_ROUTER) {
84 ifr.ifr_flags = IFF_TUN;
85 device_type = DEVICE_TYPE_TUN;
86 device_info = "Linux tun/tap device (tun mode)";
88 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
89 device_type = DEVICE_TYPE_TAP;
90 device_info = "Linux tun/tap device (tap mode)";
94 /* Set IFF_ONE_QUEUE flag... */
95 if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q)
96 ifr.ifr_flags |= IFF_ONE_QUEUE;
100 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
102 if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
103 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
104 if(iface) free(iface);
105 iface = xstrdup(ifrname);
106 } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
107 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
108 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
109 if(iface) free(iface);
110 iface = xstrdup(ifrname);
114 if(routing_mode == RMODE_ROUTER)
115 overwrite_mac = true;
116 device_info = "Linux ethertap device";
117 device_type = DEVICE_TYPE_ETHERTAP;
120 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
123 logger(LOG_INFO, "%s is a %s", device, device_info);
128 static void close_device(void) {
135 static bool read_packet(vpn_packet_t *packet) {
138 switch(device_type) {
139 case DEVICE_TYPE_TUN:
140 lenin = read(device_fd, packet->data + 10, MTU - 10);
143 logger(LOG_ERR, "Error while reading from %s %s: %s",
144 device_info, device, strerror(errno));
148 packet->len = lenin + 10;
150 case DEVICE_TYPE_TAP:
151 lenin = read(device_fd, packet->data, MTU);
154 logger(LOG_ERR, "Error while reading from %s %s: %s",
155 device_info, device, strerror(errno));
161 case DEVICE_TYPE_ETHERTAP:
162 lenin = read(device_fd, packet->data - 2, MTU + 2);
165 logger(LOG_ERR, "Error while reading from %s %s: %s",
166 device_info, device, strerror(errno));
170 packet->len = lenin - 2;
174 device_total_in += packet->len;
176 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
182 static bool write_packet(vpn_packet_t *packet) {
183 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
184 packet->len, device_info);
186 switch(device_type) {
187 case DEVICE_TYPE_TUN:
188 packet->data[10] = packet->data[11] = 0;
189 if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
190 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
195 case DEVICE_TYPE_TAP:
196 if(write(device_fd, packet->data, packet->len) < 0) {
197 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
202 case DEVICE_TYPE_ETHERTAP:
203 *(short int *)(packet->data - 2) = packet->len;
205 if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
206 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
213 device_total_out += packet->len;
218 static 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_total_in);
221 logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
224 const devops_t os_devops = {
225 .setup = setup_device,
226 .close = close_device,
228 .write = write_packet,
229 .dump_stats = dump_device_stats,