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/*
* Copyright 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* tun.c - tun device functions
*/
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <sys/ioctl.h>
#include <sys/uio.h>
#include "clatd.h"
/* function: tun_open
* tries to open the tunnel device
*/
int tun_open() {
int fd;
fd = open("/dev/tun", O_RDWR);
if(fd < 0) {
fd = open("/dev/net/tun", O_RDWR);
}
return fd;
}
/* function: tun_alloc
* creates a tun interface and names it
* dev - the name for the new tun device
*/
int tun_alloc(char *dev, int fd) {
struct ifreq ifr;
int err;
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TUN;
if( *dev ) {
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
ifr.ifr_name[IFNAMSIZ-1] = '\0';
}
if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
close(fd);
return err;
}
strcpy(dev, ifr.ifr_name);
return 0;
}
/* function: set_nonblocking
* sets a filedescriptor to non-blocking mode
* fd - the filedescriptor
* returns: 0 on success, -1 on failure
*/
int set_nonblocking(int fd) {
int flags = fcntl(fd, F_GETFL);
if (flags == -1) {
return flags;
}
return fcntl(fd, F_SETFL, flags | O_NONBLOCK);
}
/* function: send_tun
* sends a clat_packet to a tun interface
* fd - the tun filedescriptor
* out - the packet to send
* iov_len - the number of entries in the clat_packet
* returns: number of bytes read on success, -1 on failure
*/
int send_tun(int fd, clat_packet out, int iov_len) {
return writev(fd, out, iov_len);
}
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