#ifndef _NET_DN_NSP_H
  #define _NET_DN_NSP_H
  /******************************************************************************
      (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
      
      This program is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published by
      the Free Software Foundation; either version 2 of the License, or
      any later version.
  
      This program is distributed in the hope that it will be useful,
      but WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      GNU General Public License for more details.
  *******************************************************************************/
  /* dn_nsp.c functions prototyping */
  
  extern void dn_nsp_send_data_ack(struct sock *sk);
  extern void dn_nsp_send_oth_ack(struct sock *sk);
  extern void dn_nsp_delayed_ack(struct sock *sk);
  extern void dn_send_conn_ack(struct sock *sk);

  extern void dn_send_conn_conf(struct sock *sk, gfp_t gfp);

  extern void dn_nsp_send_disc(struct sock *sk, unsigned char type, 

  			unsigned short reason, gfp_t gfp);

  extern void dn_nsp_return_disc(struct sk_buff *skb, unsigned char type,
  				unsigned short reason);
  extern void dn_nsp_send_link(struct sock *sk, unsigned char lsflags, char fcval);
  extern void dn_nsp_send_conninit(struct sock *sk, unsigned char flags);
  
  extern void dn_nsp_output(struct sock *sk);
  extern int dn_nsp_check_xmit_queue(struct sock *sk, struct sk_buff *skb, struct sk_buff_head *q, unsigned short acknum);

  extern void dn_nsp_queue_xmit(struct sock *sk, struct sk_buff *skb, gfp_t gfp, int oob);

  extern unsigned long dn_nsp_persist(struct sock *sk);
  extern int dn_nsp_xmit_timeout(struct sock *sk);
  
  extern int dn_nsp_rx(struct sk_buff *);
  extern int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb);

  extern struct sk_buff *dn_alloc_skb(struct sock *sk, int size, gfp_t pri);

  extern struct sk_buff *dn_alloc_send_skb(struct sock *sk, size_t *size, int noblock, long timeo, int *err);
  
  #define NSP_REASON_OK 0		/* No error */
  #define NSP_REASON_NR 1		/* No resources */
  #define NSP_REASON_UN 2		/* Unrecognised node name */
  #define NSP_REASON_SD 3		/* Node shutting down */
  #define NSP_REASON_ID 4		/* Invalid destination end user */
  #define NSP_REASON_ER 5		/* End user lacks resources */
  #define NSP_REASON_OB 6		/* Object too busy */
  #define NSP_REASON_US 7		/* Unspecified error */
  #define NSP_REASON_TP 8		/* Third-Party abort */
  #define NSP_REASON_EA 9		/* End user has aborted the link */
  #define NSP_REASON_IF 10	/* Invalid node name format */
  #define NSP_REASON_LS 11	/* Local node shutdown */
  #define NSP_REASON_LL 32	/* Node lacks logical-link resources */
  #define NSP_REASON_LE 33	/* End user lacks logical-link resources */
  #define NSP_REASON_UR 34	/* Unacceptable RQSTRID or PASSWORD field */
  #define NSP_REASON_UA 36	/* Unacceptable ACCOUNT field */
  #define NSP_REASON_TM 38	/* End user timed out logical link */
  #define NSP_REASON_NU 39	/* Node unreachable */
  #define NSP_REASON_NL 41	/* No-link message */
  #define NSP_REASON_DC 42	/* Disconnect confirm */
  #define NSP_REASON_IO 43	/* Image data field overflow */
  
  #define NSP_DISCINIT 0x38
  #define NSP_DISCCONF 0x48
  
  /*------------------------- NSP - messages ------------------------------*/
  /* Data Messages */
  /*---------------*/
  
  /* Data Messages    (data segment/interrupt/link service)               */

  struct nsp_data_seg_msg {

  	__u8   msgflg;
  	__le16 dstaddr;
  	__le16 srcaddr;

  } __packed;

  struct nsp_data_opt_msg {

  	__le16 acknum;
  	__le16 segnum;
  	__le16 lsflgs;

  } __packed;

  struct nsp_data_opt_msg1 {

  	__le16 acknum;
  	__le16 segnum;

  } __packed;

  
  
  /* Acknowledgment Message (data/other data)                             */

  struct nsp_data_ack_msg {

  	__u8   msgflg;
  	__le16 dstaddr;
  	__le16 srcaddr;
  	__le16 acknum;

  } __packed;

  
  /* Connect Acknowledgment Message */

  struct  nsp_conn_ack_msg {

  	__u8 msgflg;
  	__le16 dstaddr;

  } __packed;

  
  
  /* Connect Initiate/Retransmit Initiate/Connect Confirm */

  struct  nsp_conn_init_msg {

  	__u8   msgflg;

  #define NSP_CI      0x18            /* Connect Initiate     */
  #define NSP_RCI     0x68            /* Retrans. Conn Init   */

  	__le16 dstaddr;
  	__le16 srcaddr;
  	__u8   services;

  #define NSP_FC_NONE   0x00            /* Flow Control None    */
  #define NSP_FC_SRC    0x04            /* Seg Req. Count       */
  #define NSP_FC_SCMC   0x08            /* Sess. Control Mess   */
  #define NSP_FC_MASK   0x0c            /* FC type mask         */

  	__u8   info;
  	__le16 segsize;

  } __packed;

  
  /* Disconnect Initiate/Disconnect Confirm */

  struct  nsp_disconn_init_msg {

  	__u8   msgflg;
  	__le16 dstaddr;
  	__le16 srcaddr;
  	__le16 reason;

  } __packed;

  struct  srcobj_fmt {

  	__u8   format;
  	__u8   task;
  	__le16 grpcode;
  	__le16 usrcode;
  	__u8   dlen;

  } __packed;

  
  /*
   * A collection of functions for manipulating the sequence
   * numbers used in NSP. Similar in operation to the functions
   * of the same name in TCP.
   */

  static __inline__ int dn_before(__u16 seq1, __u16 seq2)

  {
          seq1 &= 0x0fff;
          seq2 &= 0x0fff;
  
          return (int)((seq1 - seq2) & 0x0fff) > 2048;
  }

  static __inline__ int dn_after(__u16 seq1, __u16 seq2)

  {
          seq1 &= 0x0fff;
          seq2 &= 0x0fff;
  
          return (int)((seq2 - seq1) & 0x0fff) > 2048;
  }

  static __inline__ int dn_equal(__u16 seq1, __u16 seq2)

  {
          return ((seq1 ^ seq2) & 0x0fff) == 0;
  }

  static __inline__ int dn_before_or_equal(__u16 seq1, __u16 seq2)

  {
  	return (dn_before(seq1, seq2) || dn_equal(seq1, seq2));
  }

  static __inline__ void seq_add(__u16 *seq, __u16 off)

  {
          (*seq) += off;
          (*seq) &= 0x0fff;
  }

  static __inline__ int seq_next(__u16 seq1, __u16 seq2)

  {
  	return dn_equal(seq1 + 1, seq2);
  }
  
  /*
   * Can we delay the ack ?
   */

  static __inline__ int sendack(__u16 seq)

  {
          return (int)((seq & 0x1000) ? 0 : 1);
  }
  
  /*
   * Is socket congested ?
   */
  static __inline__ int dn_congested(struct sock *sk)
  {
          return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
  }
  
  #define DN_MAX_NSP_DATA_HEADER (11)
  
  #endif /* _NET_DN_NSP_H */