tun_solaris.c

实现vpn网关用来建立 IP虚拟隧道

#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdarg.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <signal.h>
#include <stropts.h>
#include <net/if.h>
#include <net/if_tun.h>

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#ifdef HAVE_NETINET_IN_SYSTM_H
#include <netinet/in_systm.h>
#endif

#ifdef HAVE_NETINET_IP_H
#include <netinet/ip.h>
#endif

#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
#endif

int main(int argc, char *argv[])
{
    char buf[2048], dev[10]="";
    int fd, len;

    if( (fd = tun_alloc(dev)) < 0 ){
       printf("Cannot allocate TUN device\n");
       exit(1);
    }

    while(1){
       if( (len = tun_read(fd, buf, sizeof(buf))) < 0 ){
          printf("Cannot allocate TUN device\n");
          exit(1);
       }
       printf("Received %d bytes\n", len);
    }
}

/* 
 * Allocate TUN device, returns opened fd. 
 * Stores dev name in the first arg(must be large enough).
 */  
int tun_alloc(char *dev)
{
    int tun_fd, if_fd, ppa = -1;
    static int ip_fd = 0;
    char *ptr;

    if( *dev ){
       ptr = dev;	
       while( *ptr && !isdigit((int)*ptr) ) ptr++; 
       ppa = atoi(ptr);
    }

    /* Check if IP device was opened */
    if( ip_fd )
       close(ip_fd);

    if( (ip_fd = open("/dev/ip", O_RDWR, 0)) < 0){
       syslog(LOG_ERR, "Can't open /dev/ip");
       return -1;
    }

    if( (tun_fd = open("/dev/tun", O_RDWR, 0)) < 0){
       syslog(LOG_ERR, "Can't open /dev/tun");
       return -1;
    }

    /* Assign a new PPA and get its unit number. */
    if( (ppa = ioctl(tun_fd, TUNNEWPPA, ppa)) < 0){
       syslog(LOG_ERR, "Can't assign new interface");
       return -1;
    }

    if( (if_fd = open("/dev/tun", O_RDWR, 0)) < 0){
       syslog(LOG_ERR, "Can't open /dev/tun (2)");
       return -1;
    }
    if(ioctl(if_fd, I_PUSH, "ip") < 0){
       syslog(LOG_ERR, "Can't push IP module");
       return -1;
    }

    /* Assign ppa according to the unit number returned by tun device */
    if(ioctl(if_fd, IF_UNITSEL, (char *)&ppa) < 0){
       syslog(LOG_ERR, "Can't set PPA %d", ppa);
       return -1;
    }
    if(ioctl(ip_fd, I_LINK, if_fd) < 0){
       syslog(LOG_ERR, "Can't link TUN device to IP");
       return -1;
    }

    sprintf(dev, "tun%d", ppa);
    return tun_fd;
}

int tun_write(int fd, char *buf, int len)
{
    struct strbuf sbuf;
    sbuf.len = len;      
    sbuf.buf = buf;      
    return putmsg(fd, NULL, &sbuf, 0) >=0 ? sbuf.len : -1;
}

int tun_read(int fd, char *buf, int len)
{
    struct strbuf sbuf;
    int f = 0;

    sbuf.maxlen = len;      
    sbuf.buf = buf;      
    return getmsg(fd, NULL, &sbuf, &f) >=0 ? sbuf.len : -1;
}