2 device.c -- Interaction with Linux ethertap and tun/tap device
3 Copyright (C) 2001-2005 Ivo Timmermans,
4 2001-2014 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.
21 #include "../system.h"
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"
31 #include "../device.h"
32 #include "../logger.h"
36 #include "../xalloc.h"
38 typedef enum device_type_t {
45 static device_type_t device_type;
48 static char *type = NULL;
49 static char ifrname[IFNAMSIZ];
50 static char *device_info;
52 static uint64_t device_total_in = 0;
53 static uint64_t device_total_out = 0;
55 static bool setup_device(void) {
59 if(!get_config_string(lookup_config(config_tree, "Device"), &device)) {
60 device = xstrdup(DEFAULT_DEVICE);
63 if(!get_config_string(lookup_config(config_tree, "Interface"), &iface))
64 #ifdef HAVE_LINUX_IF_TUN_H
66 iface = xstrdup(netname);
70 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
72 device_fd = open(device, O_RDWR | O_NONBLOCK);
75 logger(LOG_ERR, "Could not open %s: %s", device, strerror(errno));
80 fcntl(device_fd, F_SETFD, FD_CLOEXEC);
83 #ifdef HAVE_LINUX_IF_TUN_H
84 /* Ok now check if this is an old ethertap or a new tun/tap thingie */
86 memset(&ifr, 0, sizeof(ifr));
88 get_config_string(lookup_config(config_tree, "DeviceType"), &type);
90 if(type && strcasecmp(type, "tun") && strcasecmp(type, "tap")) {
91 logger(LOG_ERR, "Unknown device type %s!", type);
95 if((type && !strcasecmp(type, "tun")) || (!type && routing_mode == RMODE_ROUTER)) {
96 ifr.ifr_flags = IFF_TUN;
97 device_type = DEVICE_TYPE_TUN;
98 device_info = "Linux tun/tap device (tun mode)";
100 if(routing_mode == RMODE_ROUTER) {
101 overwrite_mac = true;
104 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
105 device_type = DEVICE_TYPE_TAP;
106 device_info = "Linux tun/tap device (tap mode)";
111 /* Set IFF_ONE_QUEUE flag... */
112 if(get_config_bool(lookup_config(config_tree, "IffOneQueue"), &t1q) && t1q) {
113 ifr.ifr_flags |= IFF_ONE_QUEUE;
119 strncpy(ifr.ifr_name, iface, IFNAMSIZ);
120 ifr.ifr_name[IFNAMSIZ - 1] = 0;
123 if(!ioctl(device_fd, TUNSETIFF, &ifr)) {
124 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
125 ifrname[IFNAMSIZ - 1] = 0;
127 iface = xstrdup(ifrname);
128 } else if(!ioctl(device_fd, (('T' << 8) | 202), &ifr)) {
129 logger(LOG_WARNING, "Old ioctl() request was needed for %s", device);
130 strncpy(ifrname, ifr.ifr_name, IFNAMSIZ);
131 ifrname[IFNAMSIZ - 1] = 0;
133 iface = xstrdup(ifrname);
137 if(routing_mode == RMODE_ROUTER) {
138 overwrite_mac = true;
141 device_info = "Linux ethertap device";
142 device_type = DEVICE_TYPE_ETHERTAP;
144 iface = xstrdup(strrchr(device, '/') ? strrchr(device, '/') + 1 : device);
147 if(overwrite_mac && !ioctl(device_fd, SIOCGIFHWADDR, &ifr)) {
148 memcpy(mymac.x, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
151 logger(LOG_INFO, "%s is a %s", device, device_info);
156 static void close_device(void) {
164 static bool read_packet(vpn_packet_t *packet) {
167 switch(device_type) {
168 case DEVICE_TYPE_TUN:
169 lenin = read(device_fd, packet->data + 10, MTU - 10);
172 logger(LOG_ERR, "Error while reading from %s %s: %s",
173 device_info, device, strerror(errno));
177 memset(packet->data, 0, 12);
178 packet->len = lenin + 10;
181 case DEVICE_TYPE_TAP:
182 lenin = read(device_fd, packet->data, MTU);
185 logger(LOG_ERR, "Error while reading from %s %s: %s",
186 device_info, device, strerror(errno));
193 case DEVICE_TYPE_ETHERTAP:
194 lenin = read(device_fd, packet->data - 2, MTU + 2);
197 logger(LOG_ERR, "Error while reading from %s %s: %s",
198 device_info, device, strerror(errno));
202 packet->len = lenin - 2;
206 device_total_in += packet->len;
208 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
214 static bool write_packet(vpn_packet_t *packet) {
215 ifdebug(TRAFFIC) logger(LOG_DEBUG, "Writing packet of %d bytes to %s",
216 packet->len, device_info);
218 switch(device_type) {
219 case DEVICE_TYPE_TUN:
220 packet->data[10] = packet->data[11] = 0;
222 if(write(device_fd, packet->data + 10, packet->len - 10) < 0) {
223 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
230 case DEVICE_TYPE_TAP:
231 if(write(device_fd, packet->data, packet->len) < 0) {
232 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
239 case DEVICE_TYPE_ETHERTAP:
240 memcpy(packet->data - 2, &packet->len, 2);
242 if(write(device_fd, packet->data - 2, packet->len + 2) < 0) {
243 logger(LOG_ERR, "Can't write to %s %s: %s", device_info, device,
251 device_total_out += packet->len;
256 static void dump_device_stats(void) {
257 logger(LOG_DEBUG, "Statistics for %s %s:", device_info, device);
258 logger(LOG_DEBUG, " total bytes in: %10"PRIu64, device_total_in);
259 logger(LOG_DEBUG, " total bytes out: %10"PRIu64, device_total_out);
262 const devops_t os_devops = {
263 .setup = setup_device,
264 .close = close_device,
266 .write = write_packet,
267 .dump_stats = dump_device_stats,