/* $Id: concap.h,v 1.3.2.2 2004/01/12 23:08:35 keil Exp $
   *
   * Copyright 1997 by Henner Eisen <eis@baty.hanse.de>
   *
   * This software may be used and distributed according to the terms
   * of the GNU General Public License, incorporated herein by reference.
   */
  
  #ifndef _LINUX_CONCAP_H
  #define _LINUX_CONCAP_H

  #include <linux/skbuff.h>
  #include <linux/netdevice.h>
  
  /* Stuff to support encapsulation protocols genericly. The encapsulation
     protocol is processed at the uppermost layer of the network interface.
  
     Based on a ideas developed in a 'synchronous device' thread in the
     linux-x25 mailing list contributed by Alan Cox, Thomasz Motylewski
     and Jonathan Naylor.
  
     For more documetation on this refer to Documentation/isdn/README.concap
  */
  
  struct concap_proto_ops;
  struct concap_device_ops;
  
  /* this manages all data needed by the encapsulation protocol
   */
  struct concap_proto{
  	struct net_device *net_dev;	/* net device using our service  */
  	struct concap_device_ops *dops;	/* callbacks provided by device */
   	struct concap_proto_ops  *pops;	/* callbacks provided by us */
   	spinlock_t lock;
  	int flags;
  	void *proto_data;		/* protocol specific private data, to
  					   be accessed via *pops methods only*/
  	/*
  	  :
  	  whatever 
  	  :
  	  */
  };
  
  /* Operations to be supported by the net device. Called by the encapsulation
   * protocol entity. No receive method is offered because the encapsulation
   * protocol directly calls netif_rx().
   */
  struct concap_device_ops{
  
  	/* to request data is submitted by device*/ 
  	int (*data_req)(struct concap_proto *, struct sk_buff *);
  
  	/* Control methods must be set to NULL by devices which do not
  	   support connection control.*/
  	/* to request a connection is set up */ 
  	int (*connect_req)(struct concap_proto *);
  
  	/* to request a connection is released */
  	int (*disconn_req)(struct concap_proto *);	
  };
  
  /* Operations to be supported by the encapsulation protocol. Called by
   * device driver.
   */
  struct concap_proto_ops{
  
  	/* create a new encapsulation protocol instance of same type */
  	struct concap_proto *  (*proto_new) (void);
  
  	/* delete encapsulation protocol instance and free all its resources.
  	   cprot may no loger be referenced after calling this */
  	void (*proto_del)(struct concap_proto *cprot);
  
  	/* initialize the protocol's data. To be called at interface startup
  	   or when the device driver resets the interface. All services of the
  	   encapsulation protocol may be used after this*/
  	int (*restart)(struct concap_proto *cprot, 
  		       struct net_device *ndev,
  		       struct concap_device_ops *dops);
  
  	/* inactivate an encapsulation protocol instance. The encapsulation
  	   protocol may not call any *dops methods after this. */
  	int (*close)(struct concap_proto *cprot);
  
  	/* process a frame handed down to us by upper layer */
  	int (*encap_and_xmit)(struct concap_proto *cprot, struct sk_buff *skb);
  
  	/* to be called for each data entity received from lower layer*/ 
  	int (*data_ind)(struct concap_proto *cprot, struct sk_buff *skb);
  
  	/* to be called when a connection was set up/down.
  	   Protocols that don't process these primitives might fill in
  	   dummy methods here */
  	int (*connect_ind)(struct concap_proto *cprot);
  	int (*disconn_ind)(struct concap_proto *cprot);
    /*
      Some network device support functions, like net_header(), rebuild_header(),
      and others, that depend solely on the encapsulation protocol, might
      be provided here, too. The net device would just fill them in its
      corresponding fields when it is opened.
      */
  };
  
  /* dummy restart/close/connect/reset/disconn methods
   */
  extern int concap_nop(struct concap_proto *cprot); 
  
  /* dummy submit method
   */
  extern int concap_drop_skb(struct concap_proto *cprot, struct sk_buff *skb);
  #endif