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#ifndef TUN_H_INCLUDED
#define TUN_H_INCLUDED
#endif
#include <errno.h>
#include <sys/ioctl.h>
#include <linux/if_ether.h>
#include <stddef.h>
#include <net/if.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <linux/if_tun.h>
#include <netinet/in.h>
#include <fcntl.h>
#include "mgw_utils.h"
/**************************************************************************
* tun_alloc: create a tun fd,and set tun param . *
* return : a tun fd *
**************************************************************************/
int tun_alloc(char *dev)
{
struct ifreq ifr;
int fd, err;
if ((fd = open("/dev/net/tun", O_RDWR)) < 0)
{
printf("open function errno %d is %s\n",errno,strerror(errno));
assert(0);
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TUN | IFF_NO_PI;//不包含tun包信息
if (*dev)
{
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
}
if ((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0)
{
printf("ioctl function err is %d,errno %d is %s\n",err,errno,strerror(errno));
close(fd);
assert(0);
}
strcpy(dev, ifr.ifr_name);
return fd;
}
/**************************************************************************
* read_from_tun: read data from tun , and puts them into buffer. *
* return : read bytes *
**************************************************************************/
int read_from_tun(int tun_fd, char *recv_ip_pkts,size_t ip_pkt_len)
{
int recv_ip_len = 0;
recv_ip_len = read(tun_fd, recv_ip_pkts, ip_pkt_len);
if(recv_ip_len < 0)
{
close(tun_fd);
printf("read function errno %d is %s\n",errno, strerror(errno));
assert(0);
}
else
{
return recv_ip_len;
}
}
/**************************************************************************
* write_to_tun: write data to tun *
* return:write bytes *
**************************************************************************/
int write_to_tun(int tun_fd, char *send_ip_pkts, int send_ip_len)
{
assert(send_ip_pkts !=NULL);
assert(send_ip_len > 0);
int cur_snd_ip_len = 0 ;
cur_snd_ip_len = write(tun_fd, send_ip_pkts, send_ip_len);
if(cur_snd_ip_len < 0)
{
printf(" send ip pkts errno = %d, content is %s\n",errno, strerror(errno));
assert(0);
}
else
{
if(cur_snd_ip_len < send_ip_len)
{
close(tun_fd);
printf("the ip data can not send completely!\n");
assert(0);
}
else
{
return cur_snd_ip_len;
}
}
}
int main(int argc, char* argv[])
{
char dev[MGW_SYMBOL_MAX] = "tun_mgw";
int fd = tun_alloc(dev);
char buff[1500];
int ret;
while((ret = read_from_tun(fd, buff, sizeof(buff))) > 0)
{
printf("ret is %d\n", ret);
printf("buff is %s\n", buff);
}
}
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