#

typedef unsigned short	unshort; 

/* Queue structures */
struct item {
	struct item	*q_fwd;
	struct item	*q_bwd;
	};

struct que {
	struct item	q_head;
	int		q_items;
	};


/* VII net header */
struct net_hdr {
	char	v2_dest;	/* V2 net dest. addr. */
	char	v2_src;		/* V2 net src addr. */
	char	v2_prot1;	/* MIT protocol hdr word (MPHW) */
	char	v2_prot2;	/* Subfield for MPHW */
	short	v2_zero;	/* Padding */
	};

#define	NETHSIZ		sizeof(struct net_hdr)
#define NETMAX		2046
#define INETPROT	1

/* Internet header */
struct inet_hdr	{
	char		ip_ihlver;	/* Inet hdr length in 32 bit words */
					/* Header version */
	char		ip_tsrv;	/* Type of service */
	short		ip_len;		/* Total packet length inc. header */
	unshort		ip_id;		/* Id to help in fragmentation */
	unshort		ip_frag;	/* Fragment offset/flags */
	char		ip_time;	/* Packet time to live in secs */
	char		ip_prot;	/* Protocol number */
	unshort		ip_chksum;	/* Inet hdr chksum */
	long		ip_src;		/* Source name */
	long		ip_dest;	/* Dest. name */
	};

#define	IPHSIZ		sizeof(struct inet_hdr)
#define	MAXINET		576		/* Standard max. inet pkt size */
#define IP_OPTSZ	40		/* Internet hdr - option max len */
#define IP_VERHL	0x45		/* Version, inet hdr length */
#define IP_TSRV		0		/* Type of service */
#define IP_TIME		250		/* Time to live */

#define IPOPT_SECURITY	0202		/* Security option type id */


#define	TCPPROT		6		/* Internet TCP protocol */

/* TCP Header */
struct tcp_hdr {
	unshort	tc_sskt;	/* Source socket */
	unshort	tc_dskt;	/* Destination socket */
	long	tc_seqno;	/* Sequence no. */
	long	tc_ackno;	/* Acknowledgement no. */
	char	tc_off;	/* Tcp hdr len in 32 bit wds (left 4 bits) */
	char	tc_flags;	/* Urg/Ack/Psh/Rst/Syn/Fin 
					(right 6 bits) */
	unshort	tc_window;	/* Window size */
	unshort	tc_cksum;	/* Chksum */
	unshort	tc_urgp;	/* Urgent pointer */
	};

#define TCPHSIZ	sizeof(struct tcp_hdr)

#define TELNETICP	23	/* Telnet Tcp well known skt no */
#define TESTICP		9	/* Test TCP well known skt no */

/* Tcp Flags */
#define FIN	01
#define SYN	02
#define RST	04
#define PSH	010
#define ACK	020
#define URG	040

#define RWINDOW	3500

/* Tcp header options */
struct tcp_opt {
	char	tc_okind;
	char	tc_olen;
	short	tc_odata;
	};

#define TCPOPT_MAXSEG	2

/* Tcp pseudo-header */
struct tcp_phdr {
	long	pt_src;		/* Src addr */
	long	pt_dest;	/* Dest addr */
	char	pt_zero;
	char	pt_prot;	/* Protocol */
	int	pt_len;		/* Length - tcp hdr + data */
	};

#define PTCPHSIZ	sizeof(struct tcp_phdr)

/* Tcp state bits */
#define LISTEN		0
#define SYN_SENT	01
#define SYN_ACK		02
#define SYN_RCVD	04
#define FIN_SENT	010
#define FIN_ACK		020
#define FIN_RCVD	040
#define CLOSED2		0100

#define OPEN		(SYN_SENT|SYN_ACK|SYN_RCVD)
#define CLOSED		(FIN_SENT|FIN_ACK|FIN_RCVD)