/* ip.h */

/* EMACS_MODES: c !fill */

/*
 * This file contains the structure definitions for internet headers.
 */




/* Packet Data Length */

#define	INETLEN		576		/* max. size of inet pkt in bytes */

struct	in_name	{
	char	in_net;			/* Network number */
	char	in_hhost;		/* High part of host id */
	char	in_mhost;
	char	in_lhost;		/* Low part of host id */
};

struct	ip {
	int		ip_ihl : 4;	/* IN header length in 32 bit words */
	int		ip_ver : 4;	/* Header version */
	char		ip_tsrv;	/* Type of service */
	unshort		ip_len;		/* Total pkt length including header */
	unshort		ip_id;		/* ID to help fragmentation */
	unshort		ip_foff : 13;	/* Fragment offset */
	unshort		ip_flgs : 3;	/* Flags */
	char		ip_time;	/* Life time of packet in seconds */
	char		ip_prot;	/* Protocol number */
	unshort		ip_chksum;	/* Header checksum */
	struct	in_name	ip_src;		/* Source name */
	struct	in_name	ip_dest;	/* Destination name */
};

/* Constants to fill in Internet Header */

#define	IPHSIZ	sizeof( struct ip ) 	/* internet header size */
#define	IP_VER	4			/* internet version */
#define	IP_IHL	5			/* IN header length in longwords */
#define	IP_TSRV	0			/* default type of service */
#define	IP_ID	0			/* ==> kernel fills IN id */
#define	IP_FLGS	0			/* no fragmentation yet */
#define	IP_FOFF	0			/* no fragmentation yet */
#define	IP_TIME	255			/* max. possible time to live */
#define	CHKSUM 0			/* initial checksum value */
#define	MININSIZ 8			/* min. size of IN data area */

/* Macros to swap bytes */

#ifndef	BIGINDIAN
#define	short_to_net(s)	(swab (s))
#define	long_to_net(l)	(((long)(swab (*(unshort *)(&l))) << 16) | \
(swab (*(((unshort *)&l) + 1))))
#else
#define	short_to_net(s)	(s)
#define	long_to_net(l)	(l)
#endif

/* Externals */

extern	struct	in_name	myhost;