concap.h

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/* $Id: concap.h,v 1.3.2.2 2004/01/12 23:08:35 keil Exp $
 *
 * Copyright 1997 by Henner Eisen <[email protected]>
 *
 * 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