linux/drivers/isdn/i4l/isdn_concap.c

/* $Id: isdn_concap.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
 * 
 * Linux ISDN subsystem, protocol encapsulation
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 */

/* Stuff to support the concap_proto by isdn4linux. isdn4linux - specific
 * stuff goes here. Stuff that depends only on the concap protocol goes to
 * another -- protocol specific -- source file.
 *
 */


#include <linux/isdn.h>
#include "isdn_x25iface.h"
#include "isdn_net.h"
#include <linux/concap.h>
#include "isdn_concap.h"


/* The following set of device service operations are for encapsulation
   protocols that require for reliable datalink semantics. That means:

   - before any data is to be submitted the connection must explicitly
     be set up.
   - after the successful set up of the connection is signalled the
     connection is considered to be reliably up.

   Auto-dialing ist not compatible with this requirements. Thus, auto-dialing 
   is completely bypassed.

   It might be possible to implement a (non standardized) datalink protocol
   that provides a reliable data link service while using some auto dialing
   mechanism. Such a protocol would need an auxiliary channel (i.e. user-user-
   signaling on the D-channel) while the B-channel is down.
   */


static int isdn_concap_dl_data_req(struct concap_proto *concap, struct sk_buff *skb)
{
	struct net_device *ndev = concap -> net_dev;
	isdn_net_dev *nd = ((isdn_net_local *) netdev_priv(ndev))->netdev;
	isdn_net_local *lp = isdn_net_get_locked_lp(nd);

	IX25DEBUG( "isdn_concap_dl_data_req: %s \n", concap->net_dev->name);
	if (!lp) {
		IX25DEBUG( "isdn_concap_dl_data_req: %s : isdn_net_send_skb returned %d\n", concap -> net_dev -> name, 1);
		return 1;
	}
	lp->huptimer = 0;
	isdn_net_writebuf_skb(lp, skb);
	spin_unlock_bh(&lp->xmit_lock);
	IX25DEBUG( "isdn_concap_dl_data_req: %s : isdn_net_send_skb returned %d\n", concap -> net_dev -> name, 0);
	return 0;
}


static int isdn_concap_dl_connect_req(struct concap_proto *concap)
{
	struct net_device *ndev = concap -> net_dev;
	isdn_net_local *lp = netdev_priv(ndev);
	int ret;
	IX25DEBUG( "isdn_concap_dl_connect_req: %s \n", ndev -> name);

	/* dial ... */
	ret = isdn_net_dial_req( lp );
	if ( ret ) IX25DEBUG("dialing failed\n");
	return ret;
}

static int isdn_concap_dl_disconn_req(struct concap_proto *concap)
{
	IX25DEBUG( "isdn_concap_dl_disconn_req: %s \n", concap -> net_dev -> name);

	isdn_net_hangup( concap -> net_dev );
	return 0;
}

struct concap_device_ops isdn_concap_reliable_dl_dops = {
	&isdn_concap_dl_data_req,
	&isdn_concap_dl_connect_req,
	&isdn_concap_dl_disconn_req
};

/* The following should better go into a dedicated source file such that
   this sourcefile does not need to include any protocol specific header
   files. For now:
   */
struct concap_proto * isdn_concap_new( int encap )
{
	switch ( encap ) {
	case ISDN_NET_ENCAP_X25IFACE:
		return isdn_x25iface_proto_new();
	}
	return NULL;
}