#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/stat.h>

#include <linux/if.h>
#include <linux/if_tun.h>

#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>

#include "debug.h"

/**
 * Creates a tun-interface called dev;
 * if *dev == 0, uses the name supplied by the kernel
 * returns the fd to the tun or -1
 */
int init_tun(char *dev) { /*{{{*/
	struct ifreq ifr;
	int fd, err;

	if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) {
		debug(1, 0, "opening /dev/net/tun: %s\n", strerror(errno));
		return -1;
	}

	memset(&ifr, 0, sizeof(ifr));

	ifr.ifr_flags = IFF_TUN; 
	if(dev)
		strncpy(ifr.ifr_name, dev, IFNAMSIZ);

	if ((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
		close(fd);
		debug(1, 0, "ioctl'ing /dev/net/tun: %s\n", strerror(errno));
		return err;
	}
	strcpy(dev, ifr.ifr_name);
	return fd;
} /*}}}*/

void n2o(int fd) {
	char buf[1024];
	int r, w;
	for(;;) {
		r = read(fd, buf, 1024);
		if (r < 0) {
			fprintf(stderr, "n2o read: %s\n", strerror(errno));
			exit(1);
		}
		if (r == 0) {
			close(fd);
			exit(0);
		}
		while (r > 0) {
			w = write(1, buf, r);
			if (w < 0) {
				fprintf(stderr, "n2o write: %s\n", strerror(errno));
				close(fd);
				exit(1);
			}
			r -= w;
		}
	}
}

void o2n(int fd) {
	char buf[1024];
	int r, w;
	for(;;) {
		r = read(0, buf, 1024);
		if (r < 0) {
			fprintf(stderr, "o2n read: %s\n", strerror(errno));
			exit(1);
		}
		if (r == 0) {
			close(fd);
			exit(0);
		}
		while (r > 0) {
			w = write(fd, buf, r);
			if (w < 0) {
				fprintf(stderr, "o2n write: %s\n", strerror(errno));
				close(fd);
				exit(1);
			}
			r -= w;
		}
	}
}