/* Copyright (c) University of British Columbia, 1984 */

typedef char    bool;
#define FALSE   0
#define TRUE    1

typedef u_char octet;

#define MAX_INFO_LEN    4096+3+4
#define ADDRESS_A       3	/* B'00000011' */
#define ADDRESS_B       1	/* B'00000001' */

struct Hdlc_iframe {
	octet	address;
#ifdef vax
	unsigned hdlc_0:1;
	unsigned ns:3;
	unsigned pf:1;
	unsigned nr:3;
#endif
#ifdef sun
	unsigned nr:3;
	unsigned pf:1;
	unsigned ns:3;
	unsigned hdlc_0:1;
#endif
	char    i_field[MAX_INFO_LEN];
};

struct Hdlc_sframe {
	octet	address;
#ifdef vax
	unsigned hdlc_01:2;
	unsigned s2:2;
	unsigned pf:1;
	unsigned nr:3;
#endif
#ifdef sun
	unsigned nr:3;
	unsigned pf:1;
	unsigned s2:2;
	unsigned hdlc_01:2;
#endif
};

struct	Hdlc_uframe {
	octet	address;
#ifdef vax
	unsigned hdlc_11:2;
	unsigned m2:2;
	unsigned pf:1;
	unsigned m3:3;
#endif
#ifdef sun
	unsigned m3:3;
	unsigned pf:1;
	unsigned m2:2;
	unsigned hdlc_11:2;
#endif
};

struct	Frmr_frame {
	octet	address;
	octet	control;
	octet	frmr_control;
#ifdef vax
	unsigned frmr_f2_0:1;
	unsigned frmr_ns:3;
	unsigned frmr_f1_0:1;
	unsigned frmr_nr:3;
#endif
#ifdef sun
	unsigned frmr_nr:3;
	unsigned frmr_f1_0:1;
	unsigned frmr_ns:3;
	unsigned frmr_f2_0:1;
#endif
#ifdef vax
	unsigned frmr_w:1;
	unsigned frmr_x:1;
	unsigned frmr_y:1;
	unsigned frmr_z:1;
	unsigned frmr_0000:4;
#endif
#ifdef sun
	unsigned frmr_0000:4;
	unsigned frmr_z:1;
	unsigned frmr_y:1;
	unsigned frmr_x:1;
	unsigned frmr_w:1;
#endif
};

#define HDHEADERLN	2
#define MINFRLN		2		/* Minimum frame length. */

struct	Hdlc_frame {
	octet	address;
	octet	control;
	char	info[3];	/* min for FRMR */
};

#define SABM_CONTROL 057	/* B'00101111' */
#define UA_CONTROL   0143	/* B'01100011' */
#define DISC_CONTROL 0103	/* B'01000011' */
#define DM_CONTROL   017	/* B'00001111' */
#define FRMR_CONTROL 0207	/* B'10000111' */
#define RR_CONTROL   01		/* B'00000001' */
#define RNR_CONTROL  05		/* B'00000101' */
#define REJ_CONTROL  011	/* B'00001001' */

#define POLLOFF  0
#define POLLON   1

/* Define Link State constants. */

#define INIT		0
#define DM_SENT		1
#define SABM_SENT	2
#define ABM		3
#define WAIT_SABM	4
#define WAIT_UA		5
#define DISC_SENT	6
#define DISCONNECTED	7
#define MAXSTATE	8

/* The following constants are used in a switch statement to process
   frames read from the communications line. */

#define SABM     0 * MAXSTATE
#define DM       1 * MAXSTATE
#define DISC     2 * MAXSTATE
#define UA       3 * MAXSTATE
#define FRMR     4 * MAXSTATE
#define RR       5 * MAXSTATE
#define RNR      6 * MAXSTATE
#define REJ      7 * MAXSTATE
#define IFRAME   8 * MAXSTATE
#define ILLEGAL  9 * MAXSTATE

#define T1	(3 * PR_SLOWHZ)		/*  IFRAME TIMEOUT - 3 seconds */
#define T3	(T1 / 2)		/*  RR generate timeout - 1.5 seconds */
#define N2	10
#define MODULUS 8
#define MAX_WINDOW_SIZE 7

#define Z  0
#define Y  1
#define X  2
#define W  3
#define A  4

#define TX 0
#define RX 1

bool	range_check ();
bool	valid_nr ();
struct	mbuf *hd_remove ();