89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
/*
|
|
* 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);
|
|
}
|