# concap.h

    /* $Id$
    */
    #ifndef _LINUX_CONCAP_H
    #define _LINUX_CONCAP_H
    #ifdef __KERNEL__
    #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.

       (c) 1997 by Henner Eisen <eis@baty.hanse.de>
       This software is subject to the GNU General Public License.

       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 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 */
    	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 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
    #endif