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/* tun.c system tunnel driver interface
*
* $Id: tun.c,v 1.3 1995/03/19 17:21:06 bdale Exp $
*
* Copyright 1991, Michael Westerhof, Sun Microsystems, Inc.
* This software may be freely used, distributed, or modified, providing
* this header is not removed.
*
*/
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <fcntl.h>
#include <memory.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <syslog.h>
#include <unistd.h>
#include "ipip.h"
#ifndef FNDELAY
#define FNDELAY O_NDELAY
#endif
extern int errno;
#define IF_NAME "tun" /* for use with the error checking macros */
/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* open and initialize the IO interface. Return -1 for error.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
int tun_open(ifp)
struct interface *ifp;
{
CK_IFNULL(ifp);
CK_IFTYPE(ifp,IF_TYPE_TUN);
if((ifp->status & IF_STAT_OPEN)) return 1;
ifp->fd = open(ifp->devname, O_RDWR);
if (ifp->fd<0) {
PERR(ifp->devname);
return -1;
}
if (fcntl(ifp->fd, F_SETFL, FNDELAY) < 0) {
PERR("setting non-blocking I/O on tunnel device");
return -1;
}
ifp->status = IF_STAT_OPEN;
return 1;
}
/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Read data from the specified interface. Return a complete IP datagram.
* If the packet is not complete, then don't return anything.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
int tun_read(ifp, m)
struct interface *ifp;
struct message *m;
{
int n;
CK_IFNULL(ifp);
CK_IFTYPE(ifp,IF_TYPE_TUN);
CK_IFOPEN(ifp);
CK_MNULL(m);
n = read(ifp->fd, (char *)m->msg, MAX_SIZE);
if(n<0){
m->length = 0;
if(errno==EINTR)return 0;
if(errno==EWOULDBLOCK)return 0;
PERR("read from tunnel device");
return -1;
}
m->length = n;
return n;
}
/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* write data from to the specified interface. Return as soon as possible.
* The buffer provided will be a complete IP datagram.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
int tun_send(ifp, m)
struct interface *ifp; /* the interface */
struct message *m; /* the message */
{
int n;
CK_IFNULL(ifp);
CK_IFTYPE(ifp,IF_TYPE_TUN);
CK_IFOPEN(ifp);
CK_MNULL(m);
if(m->length<=0)return 0;
n = write(ifp->fd, (char *)m->msg, m->length);
if(n<0){
if(errno==EINTR)return 0;
if(errno==EWOULDBLOCK){ /* should never happen :-) */
ifp->out_overruns++;
return 0;
}
PERR("write to tunnel device");
return -1;
}
if(n < m->length)ifp->out_overruns++;
return n;
}
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