LXR linux/drivers/isdn/i4l/isdn

   1/* $Id: isdn_concap.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
   2 * 
   3 * Linux ISDN subsystem, protocol encapsulation
   4 *
   5 * This software may be used and distributed according to the terms
   6 * of the GNU General Public License, incorporated herein by reference.
   7 *
   8 */
   9
  10/* Stuff to support the concap_proto by isdn4linux. isdn4linux - specific
  11 * stuff goes here. Stuff that depends only on the concap protocol goes to
  12 * another -- protocol specific -- source file.
  13 *
  14 */
  15
  16
  17#include <linux/isdn.h>
  18#include "isdn_x25iface.h"
  19#include "isdn_net.h"
  20#include <linux/concap.h>
  21#include "isdn_concap.h"
  22
  23
  24/* The following set of device service operations are for encapsulation
  25   protocols that require for reliable datalink semantics. That means:
  26
  27   - before any data is to be submitted the connection must explicitly
  28     be set up.
  29   - after the successful set up of the connection is signalled the
  30     connection is considered to be reliably up.
  31
  32   Auto-dialing ist not compatible with this requirements. Thus, auto-dialing 
  33   is completely bypassed.
  34
  35   It might be possible to implement a (non standardized) datalink protocol
  36   that provides a reliable data link service while using some auto dialing
  37   mechanism. Such a protocol would need an auxiliary channel (i.e. user-user-
  38   signaling on the D-channel) while the B-channel is down.
  39   */
  40
  41
  42static int isdn_concap_dl_data_req(struct concap_proto *concap, struct sk_buff *skb)
  43{
  44        struct net_device *ndev = concap -> net_dev;
  45        isdn_net_dev *nd = ((isdn_net_local *) ndev->priv)->netdev;
  46        isdn_net_local *lp = isdn_net_get_locked_lp(nd);
  47
  48        IX25DEBUG( "isdn_concap_dl_data_req: %s \n", concap->net_dev->name);
  49        if (!lp) {
  50                IX25DEBUG( "isdn_concap_dl_data_req: %s : isdn_net_send_skb returned %d\n", concap -> net_dev -> name, 1);
  51                return 1;
  52        }
  53        lp->huptimer = 0;
  54        isdn_net_writebuf_skb(lp, skb);
  55        spin_unlock_bh(&lp->xmit_lock);
  56        IX25DEBUG( "isdn_concap_dl_data_req: %s : isdn_net_send_skb returned %d\n", concap -> net_dev -> name, 0);
  57        return 0;
  58}
  59
  60
  61static int isdn_concap_dl_connect_req(struct concap_proto *concap)
  62{
  63        struct net_device *ndev = concap -> net_dev;
  64        isdn_net_local *lp = (isdn_net_local *) ndev->priv;
  65        int ret;
  66        IX25DEBUG( "isdn_concap_dl_connect_req: %s \n", ndev -> name);
  67
  68        /* dial ... */
  69        ret = isdn_net_dial_req( lp );
  70        if ( ret ) IX25DEBUG("dialing failed\n");
  71        return ret;
  72}
  73
  74static int isdn_concap_dl_disconn_req(struct concap_proto *concap)
  75{
  76        IX25DEBUG( "isdn_concap_dl_disconn_req: %s \n", concap -> net_dev -> name);
  77
  78        isdn_net_hangup( concap -> net_dev );
  79        return 0;
  80}
  81
  82struct concap_device_ops isdn_concap_reliable_dl_dops = {
  83        &isdn_concap_dl_data_req,
  84        &isdn_concap_dl_connect_req,
  85        &isdn_concap_dl_disconn_req
  86};
  87
  88/* The following should better go into a dedicated source file such that
  89   this sourcefile does not need to include any protocol specific header
  90   files. For now:
  91   */
  92struct concap_proto * isdn_concap_new( int encap )
  93{
  94        switch ( encap ) {
  95        case ISDN_NET_ENCAP_X25IFACE:
  96                return isdn_x25iface_proto_new();
  97        }
  98        return NULL;
  99}
 100