tun.c

本人收集整理的一份c/c++跨平台网络库

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

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

#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <net/if.h>

#include <linux/if_tun.h>

extern int debug;

int
tun_open(char *dev) {
	struct ifreq ifr;
	int fd, err;

	if( (fd = open("/dev/net/tun", O_RDWR)) < 0 )
		return fd;

	memset(&ifr, 0, sizeof(ifr));
	ifr.ifr_flags = IFF_TUN | IFF_NO_PI;

	if( dev )
		strncpy(ifr.ifr_name, dev, IFNAMSIZ);
	else
		dev = malloc(sizeof(ifr.ifr_name));

	if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
		close(fd);
		return err;
	}

	if (debug) printf("dev: %s\n", dev);
	strcpy(dev, ifr.ifr_name);
	return fd;
}

int
tun_close(int fd) {
	return close(fd);
}

int
tun_write(int fd, char *buf, int len) {
	register int t=0, w;

	while ( len > 0) {
		if( (w = write(fd, buf, len)) < 0 ){
			if( errno == EINTR || errno == EAGAIN )
				continue;
			return -1;
		}
	  
		if( !w )
			return 0;
	  len -= w; buf += w; t += w;
	}

	return t;
}

int
tun_read(int fd, char *buf, int len) {
    return read(fd, buf, len);
}