#
/* in_alloc.c */

/* EMACS_MODES: c !fill */


/* Internet protocol layer for the MIT network system.  The following
 * routines are included:
 *	in_alloc		Allocate an internet packet buffer
 *	in_free			Free an internet packet buffer
 *
 * Note that use of this package requires the use of the standard I/O
 * library.
 */


#include	<err.h>
#include	<stdio.h>
#include	<ioctl.h>
#include	<ip.h>
#include	<netdefs.h>


caddr_t	in_alloc (datalen, optlen)

/* Allocate the storage for a packet with data area of size datalen,
 * and including space for an option string of length optlen,
 * including space for local net header and trailer and for internet
 * header.  The length will be increased to an even number of bytes
 * if needed.  Set up the internet header length fields so in_data()
 * will work properly.  Return a pointer to the allocated packet,
 * or NULL if unable to allocate one.
 *
 * Arguments:
 */

reg	int	datalen;		/* length of data area in bytes */
int	optlen;				/* option string length in bytes */
{
	caddr_t	pkt;			/* ptr. to allocated packet */
	reg	struct	ip	*pip;	/* ptr. to internet header */
	reg	int	len;		/* total packet length	*/
	
	optlen = (optlen + 3) & ~3;	/* round option len up */
	len = lnhsiz + IPHSIZ + optlen + datalen + lntsiz;
	len = (len + 1) & ~1;		/* round up to even byte size */
	if ((pkt = calloc (1, len)) == NULL)
		return (NULL);
	pip = in_head(pkt);
	pip->ip_ihl = IP_IHL + (optlen >> 2);
	return (pkt);
}


in_free (pkt)

/* Free the packet pointed to by pkt.  Just call down to the C free
 * routine.
 *
 * Arguments:
 */

caddr_t	pkt;				/* ptr. to pkt to free */
{
	cfree (pkt);
}