Category : Network Files
Archive   : KA9Q.ZIP
Filename : NR4.H

/* nr4.h: defines for netrom layer 4 (transport) support.
* Copyright 1989 by Daniel M. Frank, W9NK. Permission granted for
* non-commercial distribution only.
*/

/* compile-time limitations */

#define NR4MAXCIRC 20 /* maximum number of open circuits */
#define NR4MAXWIN 127 /* maximum window size, send and receive */

/* protocol limitation: */

#define NR4MAXINFO 236 /* maximum data in an info packet */

/* sequence number wraparound mask */

#define NR4SEQMASK 0xff /* eight-bit sequence numbers */

/* flags in high nybble of opcode byte */

#define NR4CHOKE 0x80
#define NR4NAK 0x40
#define NR4MORE 0x20 /* The "more follows" flag for */
/* pointless packet reassembly */

/* mask for opcode nybble */

#define NR4OPCODE 0x0f

/* opcodes */

#define NR4OPPID 0 /* protocol ID extension to network layer */
#define NR4OPCONRQ 1 /* connect request */
#define NR4OPCONAK 2 /* connect acknowledge */
#define NR4OPDISRQ 3 /* disconnect request */
#define NR4OPDISAK 4 /* disconnect acknowledge */
#define NR4OPINFO 5 /* information packet */
#define NR4OPACK 6 /* information ACK */
#define NR4NUMOPS 7 /* number of transport opcodes */

/* minimum length of NET/ROM transport header */

#define NR4MINHDR 5

/* host format net/rom transport header */

struct nr4hdr {
unsigned char opcode ; /* opcode and flags */
unsigned char yourindex ; /* receipient's circuit index */
unsigned char yourid ; /* receipient's circuit ID */

union {

struct { /* network extension */
unsigned char family ; /* protocol family */
unsigned char proto ; /* protocol within family */
} pid ;

struct { /* connect request */
unsigned char myindex ; /* sender's circuit index */
unsigned char myid ; /* sender's circuit ID */
unsigned char window ; /* sender's proposed window size */
struct ax25_addr user ; /* callsign of originating user */
struct ax25_addr node ; /* callsign of originating node */
} conreq ;

struct { /* connect acknowledge */
unsigned char myindex ; /* sender's circuit index */
unsigned char myid ; /* sender's circuit ID */
unsigned char window ; /* accepted window size */
} conack ;

struct { /* information */
unsigned char txseq ; /* sender's tx sequence number */
unsigned char rxseq ; /* sender's rx sequence number */
} info ;

struct { /* information acknowledge */
unsigned char rxseq ; /* sender's rx sequence number */
} ack ;

} u ; /* End of union */

} ;

/* The netrom circuit pointer structure */

struct nr4circp {
unsigned char cid ; /* circuit ID; incremented each time*/
/* this circuit is used */
struct nr4cb *ccb ; /* pointer to circuit control block, */
/* NULLNR4CB if not in use */
} ;

/* The circuit table: */

extern struct nr4circp Nr4circuits[NR4MAXCIRC] ;

/* A netrom send buffer structure */

struct nr4txbuf {
struct timer tretry ; /* retry timer */
unsigned retries ; /* number of retries */
struct mbuf *data ; /* data sent but not acknowledged */
} ;

/* A netrom receive buffer structure */

struct nr4rxbuf {
unsigned char occupied ; /* flag: buffer in use */
struct mbuf *data ; /* data received out of sequence */
} ;

/* The netrom circuit control block */

struct nr4cb {
unsigned mynum ; /* my circuit number */
unsigned myid ; /* my circuit ID */
unsigned yournum ; /* remote circuit number */
unsigned yourid ; /* remote circuit ID */
struct ax25_addr user ; /* callsign of originating user (if any) */
struct ax25_addr node ; /* callsign of remote node */
struct ax25_addr luser ; /* callsign of local "user", for connections */
/* that we initiate */
unsigned window ; /* negotiated window size */

/* Data for round trip timer calculation and setting */

long srtt ; /* Smoothed round trip time */
long mdev ; /* Mean deviation in round trip time */
unsigned blevel ; /* Backoff level */
unsigned txmax ; /* The maximum number of retries among */
/* the frames in the window. This is 0 */
/* if there are no frames in the window. */
/* It is used as a baseline to determine */
/* when to increment the backoff level. */

/* flags */

char choked ; /* choke received from remote */
char qfull ; /* receive queue is full, and we have */
/* choked the other end */
char naksent ; /* a NAK has already been sent */

/* transmit buffers and window variables */

struct nr4txbuf *txbufs ; /* pointer to array[windowsize] of bufs */
unsigned char nextosend ; /* sequence # of next frame to send */
unsigned char ackxpected ; /* sequence number of next expected ACK */
unsigned nbuffered ; /* number of buffered TX frames */
struct mbuf *txq ; /* queue of unsent data */

/* receive buffers and window variables */

struct nr4rxbuf *rxbufs ; /* pointer to array[windowsize] of bufs */
unsigned char rxpected ; /* # of next receive frame expected */
unsigned char rxpastwin ; /* top of RX window + 1 */
struct mbuf *rxq ; /* "fully" received data queue */

/* Connection state */

int state ; /* connection state */
#define NR4STDISC 0 /* disconnected */
#define NR4STCPEND 1 /* connection pending */
#define NR4STCON 2 /* connected */
#define NR4STDPEND 3 /* disconnect requested locally */

int dreason ; /* Reason for disconnect */
#define NR4RNORMAL 0 /* Normal, requested disconnect */
#define NR4RREMOTE 1 /* Remote requested */
#define NR4RTIMEOUT 2 /* Connection timed out */
#define NR4RRESET 3 /* Connection reset locally */
#define NR4RREFUSED 4 /* Connect request refused */

/* Per-connection timers */

struct timer tchoke ; /* choke timeout */
struct timer tack ; /* ack delay timer */

struct timer tcd ; /* connect/disconnect timer */
unsigned cdtries ; /* Number of connect/disconnect tries */

void (*r_upcall)() ; /* receive upcall */
void (*t_upcall)() ; /* transmit upcall */
void (*s_upcall)() ; /* state change upcall */

char *puser ; /* user pointer */
} ;

#define NULLNR4CB (struct nr4cb *)0

/* Some globals */

extern unsigned Nr4window ; /* The advertised window size, in frames */
extern long Nr4irtt ; /* The initial round trip time */
extern unsigned Nr4retries ; /* The number of times to retry */
extern long Nr4acktime ; /* How long to wait until ACK'ing */
extern char *Nr4states[] ; /* NET/ROM state names */
extern char *Nr4reasons[] ; /* Disconnect reason names */
extern unsigned Nr4qlimit ; /* max receive queue length before CHOKE */
extern long Nr4choketime ; /* CHOKEd state timeout */

#if UNIX || ATARI_ST
/* function definitions */

/* In nr4subr.c: */

extern int ntohnr4() ;
extern struct mbuf *htonnr4() ;
extern struct nr4cb *new_n4circ() ;
extern int init_nr4window() ;
extern void free_n4circ() ;
extern struct nr4cb *match_n4circ() ;
extern struct nr4cb *get_n4circ() ;
extern int nr4between() ;
extern void nr4defaults() ;
extern int nr4valcb() ;

/* In nr4.c: */

extern void nr4sframe() ;
extern void nr4rframe() ;
extern void nr4sbuf() ;
extern void nr4ackours() ;
extern void nr4gotnak() ;
extern int nr4output() ;
extern void nr4state() ;
extern void nr4choke() ;

/* In nr4timer.c */

extern void nr4txtimeout() ;
extern void nr4ackit() ;
extern void nr4cdtimeout() ;
extern void nr4unchoke() ;

/* In nr4user.c: */

extern struct nr4cb *open_nr4() ;
extern int send_nr4() ;
extern struct mbuf *recv_nr4() ;
extern void disc_nr4() ;
extern void reset_nr4() ;
extern int kick_nr4() ;

/* In nrcmd.c: */

extern void nr4_state() ;
extern void nr4_parse() ;
extern void nr4_incom() ;
extern void nr4_rx() ;
extern void nr4_tx() ;

#else

/* function definitions */

/* In nr4subr.c: */

extern int ntohnr4(struct nr4hdr *, struct mbuf **) ;
extern struct mbuf *htonnr4(struct nr4hdr *) ;
extern struct nr4cb *new_n4circ() ;
extern int init_nr4window(struct nr4cb *, unsigned) ;
extern void free_n4circ(struct nr4cb *) ;
extern struct nr4cb *match_n4circ(int, int,
struct ax25_addr *, struct ax25_addr *) ;
extern struct nr4cb *get_n4circ(int, int) ;
extern int nr4between(unsigned, unsigned, unsigned) ;
extern void nr4defaults(struct nr4cb *) ;
extern int nr4valcb(struct nr4cb *) ;

/* In nr4.c: */

extern void nr4sframe(struct ax25_addr *, struct nr4hdr *, struct mbuf *) ;
extern void nr4rframe(struct nr4cb *, unsigned, struct mbuf *) ;
extern void nr4sbuf(struct nr4cb *, unsigned) ;
extern void nr4ackours(struct nr4cb *, unsigned, int) ;
extern void nr4gotnak(struct nr4cb *, unsigned) ;
extern int nr4output(struct nr4cb *) ;
extern void nr4state(struct nr4cb *, int) ;
extern void nr4choke(struct nr4cb *) ;

/* In nr4timer.c */

extern void nr4txtimeout(char *) ;
extern void nr4ackit(char *) ;
extern void nr4cdtimeout(char *) ;
extern void nr4unchoke(char *) ;

/* In nr4user.c: */

extern struct nr4cb *open_nr4(struct ax25_addr *, struct ax25_addr *,
void (*)(), void (*)(), void (*)(),
char *) ;
extern int send_nr4(struct nr4cb *, struct mbuf *) ;
extern struct mbuf *recv_nr4(struct nr4cb *, int16) ;
extern void disc_nr4(struct nr4cb *) ;
extern void reset_nr4(struct nr4cb *) ;
extern int kick_nr4(struct nr4cb *) ;

/* In nrcmd.c: */

extern void nr4_state(struct nr4cb *, int, int) ;
extern void nr4_parse(char *, int16) ;
extern void nr4_incom(struct nr4cb *, int, int) ;
extern void nr4_rx(struct nr4cb *, int16) ;
extern void nr4_tx(struct nr4cb *, int16) ;

#endif