/*********************************************************************
   *                
   * Filename:      irttp.h
   * Version:       1.0
   * Description:   Tiny Transport Protocol (TTP) definitions
   * Status:        Experimental.
   * Author:        Dag Brattli <dagb@cs.uit.no>
   * Created at:    Sun Aug 31 20:14:31 1997
   * Modified at:   Sun Dec 12 13:09:07 1999
   * Modified by:   Dag Brattli <dagb@cs.uit.no>
   * 
   *     Copyright (c) 1998-1999 Dag Brattli <dagb@cs.uit.no>, 
   *     All Rights Reserved.
   *     Copyright (c) 2000-2002 Jean Tourrilhes <jt@hpl.hp.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 (at your option) any later version.
   *
   *     Neither Dag Brattli nor University of Tromsø admit liability nor
   *     provide warranty for any of this software. This material is 
   *     provided "AS-IS" and at no charge.
   *
   ********************************************************************/
  
  #ifndef IRTTP_H
  #define IRTTP_H
  
  #include <linux/types.h>
  #include <linux/skbuff.h>
  #include <linux/spinlock.h>
  
  #include <net/irda/irda.h>
  #include <net/irda/irlmp.h>		/* struct lsap_cb */
  #include <net/irda/qos.h>		/* struct qos_info */
  #include <net/irda/irqueue.h>
  
  #define TTP_MAX_CONNECTIONS    LM_MAX_CONNECTIONS
  #define TTP_HEADER             1
  #define TTP_MAX_HEADER         (TTP_HEADER + LMP_MAX_HEADER)
  #define TTP_SAR_HEADER         5
  #define TTP_PARAMETERS         0x80
  #define TTP_MORE               0x80
  
  /* Transmission queue sizes */
  /* Worst case scenario, two window of data - Jean II */
  #define TTP_TX_MAX_QUEUE	14
  /* We need to keep at least 5 frames to make sure that we can refill
   * appropriately the LAP layer. LAP keeps only two buffers, and we need
   * to have 7 to make a full window - Jean II */
  #define TTP_TX_LOW_THRESHOLD	5
  /* Most clients are synchronous with respect to flow control, so we can
   * keep a low number of Tx buffers in TTP - Jean II */
  #define TTP_TX_HIGH_THRESHOLD	7
  
  /* Receive queue sizes */
  /* Minimum of credit that the peer should hold.
   * If the peer has less credits than 9 frames, we will explicitly send
   * him some credits (through irttp_give_credit() and a specific frame).
   * Note that when we give credits it's likely that it won't be sent in
   * this LAP window, but in the next one. So, we make sure that the peer
   * has something to send while waiting for credits (one LAP window == 7
   * + 1 frames while he process the credits). - Jean II */
  #define TTP_RX_MIN_CREDIT	8
  /* This is the default maximum number of credits held by the peer, so the
   * default maximum number of frames he can send us before needing flow
   * control answer from us (this may be negociated differently at TSAP setup).
   * We want to minimise the number of times we have to explicitly send some
   * credit to the peer, hoping we can piggyback it on the return data. In
   * particular, it doesn't make sense for us to send credit more than once
   * per LAP window.
   * Moreover, giving credits has some latency, so we need strictly more than
   * a LAP window, otherwise we may already have credits in our Tx queue.
   * But on the other hand, we don't want to keep too many Rx buffer here
   * before starting to flow control the other end, so make it exactly one
   * LAP window + 1 + MIN_CREDITS. - Jean II */
  #define TTP_RX_DEFAULT_CREDIT	16
  /* Maximum number of credits we can allow the peer to have, and therefore
   * maximum Rx queue size.
   * Note that we try to deliver packets to the higher layer every time we
   * receive something, so in normal mode the Rx queue will never contains
   * more than one or two packets. - Jean II */
  #define TTP_RX_MAX_CREDIT	21
  
  /* What clients should use when calling ttp_open_tsap() */
  #define DEFAULT_INITIAL_CREDIT	TTP_RX_DEFAULT_CREDIT
  
  /* Some priorities for disconnect requests */
  #define P_NORMAL    0
  #define P_HIGH      1
  
  #define TTP_SAR_DISABLE 0
  #define TTP_SAR_UNBOUND 0xffffffff
  
  /* Parameters */
  #define TTP_MAX_SDU_SIZE 0x01
  
  /*
   *  This structure contains all data associated with one instance of a TTP 
   *  connection.
   */
  struct tsap_cb {
  	irda_queue_t q;            /* Must be first */
  	magic_t magic;        /* Just in case */
  
  	__u8 stsap_sel;       /* Source TSAP */
  	__u8 dtsap_sel;       /* Destination TSAP */
  
  	struct lsap_cb *lsap; /* Corresponding LSAP to this TSAP */
  
  	__u8 connected;       /* TSAP connected */
  	 
  	__u8 initial_credit;  /* Initial credit to give peer */
  
          int avail_credit;    /* Available credit to return to peer */
  	int remote_credit;   /* Credit held by peer TTP entity */
  	int send_credit;     /* Credit held by local TTP entity */
  	
  	struct sk_buff_head tx_queue; /* Frames to be transmitted */
  	struct sk_buff_head rx_queue; /* Received frames */
  	struct sk_buff_head rx_fragments;
  	int tx_queue_lock;
  	int rx_queue_lock;
  	spinlock_t lock;
  
  	notify_t notify;       /* Callbacks to client layer */
  
  	struct net_device_stats stats;
  	struct timer_list todo_timer; 
  
  	__u32 max_seg_size;     /* Max data that fit into an IrLAP frame */
  	__u8  max_header_size;
  
  	int   rx_sdu_busy;     /* RxSdu.busy */
  	__u32 rx_sdu_size;     /* Current size of a partially received frame */
  	__u32 rx_max_sdu_size; /* Max receive user data size */
  
  	int tx_sdu_busy;       /* TxSdu.busy */
  	__u32 tx_max_sdu_size; /* Max transmit user data size */
  
  	int close_pend;        /* Close, but disconnect_pend */
  	unsigned long disconnect_pend; /* Disconnect, but still data to send */
  	struct sk_buff *disconnect_skb;
  };
  
  struct irttp_cb {
  	magic_t    magic;	
  	hashbin_t *tsaps;
  };
  
  int  irttp_init(void);
  void irttp_cleanup(void);
  
  struct tsap_cb *irttp_open_tsap(__u8 stsap_sel, int credit, notify_t *notify);
  int irttp_close_tsap(struct tsap_cb *self);
  
  int irttp_data_request(struct tsap_cb *self, struct sk_buff *skb);
  int irttp_udata_request(struct tsap_cb *self, struct sk_buff *skb);
  
  int irttp_connect_request(struct tsap_cb *self, __u8 dtsap_sel, 
  			  __u32 saddr, __u32 daddr,
  			  struct qos_info *qos, __u32 max_sdu_size, 
  			  struct sk_buff *userdata);
  int irttp_connect_response(struct tsap_cb *self, __u32 max_sdu_size, 
  			    struct sk_buff *userdata);
  int irttp_disconnect_request(struct tsap_cb *self, struct sk_buff *skb,
  			     int priority);
  void irttp_flow_request(struct tsap_cb *self, LOCAL_FLOW flow);
  struct tsap_cb *irttp_dup(struct tsap_cb *self, void *instance);
  
  static inline __u32 irttp_get_saddr(struct tsap_cb *self)
  {
  	return irlmp_get_saddr(self->lsap);
  }
  
  static inline __u32 irttp_get_daddr(struct tsap_cb *self)
  {
  	return irlmp_get_daddr(self->lsap);
  }
  
  static inline __u32 irttp_get_max_seg_size(struct tsap_cb *self)
  {
  	return self->max_seg_size;
  }
  
  /* After doing a irttp_dup(), this get one of the two socket back into
   * a state where it's waiting incoming connections.
   * Note : this can be used *only* if the socket is not yet connected
   * (i.e. NO irttp_connect_response() done on this socket).
   * - Jean II */
  static inline void irttp_listen(struct tsap_cb *self)
  {
  	irlmp_listen(self->lsap);
  	self->dtsap_sel = LSAP_ANY;
  }
  
  /* Return TRUE if the node is in primary mode (i.e. master)
   * - Jean II */
  static inline int irttp_is_primary(struct tsap_cb *self)
  {
  	if ((self == NULL) ||
  	    (self->lsap == NULL) ||
  	    (self->lsap->lap == NULL) ||
  	    (self->lsap->lap->irlap == NULL))
  		return -2;
  	return irlap_is_primary(self->lsap->lap->irlap);
  }
  
  #endif /* IRTTP_H */