drivers/isdn/isdn_concap.c

   1 /* $Id: isdn_concap.c,v 1.8 2000/05/11 22:29:20 kai Exp $
   2
   3  * Linux ISDN subsystem, protocol encapsulation
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  */
  20
  21 /* Stuff to support the concap_proto by isdn4linux. isdn4linux - specific
  22  * stuff goes here. Stuff that depends only on the concap protocol goes to
  23  * another -- protocol specific -- source file.
  24  *
  25  */
  26
  27
  28 #include <linux/isdn.h>
  29 #include "isdn_x25iface.h"
  30 #include "isdn_net.h"
  31 #include <linux/concap.h>
  32 #include "isdn_concap.h"
  33
  34
  35 /* The following set of device service operations are for encapsulation
  36    protocols that require for reliable datalink semantics. That means:
  37
  38    - before any data is to be submitted the connection must explicitly
  39      be set up.
  40    - after the successful set up of the connection is signalled the
  41      connection is considered to be reliably up.
  42
  43    Auto-dialing ist not compatible with this requirements. Thus, auto-dialing
  44    is completely bypassed.
  45
  46    It might be possible to implement a (non standardized) datalink protocol
  47    that provides a reliable data link service while using some auto dialing
  48    mechanism. Such a protocol would need an auxiliary channel (i.e. user-user-
  49    signaling on the D-channel) while the B-channel is down.
  50    */
  51
  52
  53 int isdn_concap_dl_data_req(struct concap_proto *concap, struct sk_buff *skb)
  54 {
  55         struct net_device *ndev = concap -> net_dev;
  56         isdn_net_dev *nd = ((isdn_net_local *) ndev->priv)->netdev;
  57         isdn_net_local *lp = isdn_net_get_locked_lp(nd);
  58
  59         IX25DEBUG( "isdn_concap_dl_data_req: %s \n", concap->net_dev->name);
  60         if (!lp) {
  61                 IX25DEBUG( "isdn_concap_dl_data_req: %s : isdn_net_send_skb returned %d\n", concap -> net_dev -> name, 1);
  62                 return 1;
  63         }
  64         lp->huptimer = 0;
  65         isdn_net_writebuf_skb(lp, skb);
  66         spin_unlock_bh(&lp->xmit_lock);
  67         IX25DEBUG( "isdn_concap_dl_data_req: %s : isdn_net_send_skb returned %d\n", concap -> net_dev -> name, 0);
  68         return 0;
  69 }
  70
  71
  72 int isdn_concap_dl_connect_req(struct concap_proto *concap)
  73 {
  74         struct net_device *ndev = concap -> net_dev;
  75         isdn_net_local *lp = (isdn_net_local *) ndev->priv;
  76         int ret;
  77         IX25DEBUG( "isdn_concap_dl_connect_req: %s \n", ndev -> name);
  78
  79         /* dial ... */
  80         ret = isdn_net_dial_req( lp );
  81         if ( ret ) IX25DEBUG("dialing failed\n");
  82         return ret;
  83 }
  84
  85 int isdn_concap_dl_disconn_req(struct concap_proto *concap)
  86 {
  87         IX25DEBUG( "isdn_concap_dl_disconn_req: %s \n", concap -> net_dev -> name);
  88
  89         isdn_net_hangup( concap -> net_dev );
  90         return 0;
  91 }
  92
  93 struct concap_device_ops isdn_concap_reliable_dl_dops = {
  94         &isdn_concap_dl_data_req,
  95         &isdn_concap_dl_connect_req,
  96         &isdn_concap_dl_disconn_req
  97 };
  98
  99 struct concap_device_ops isdn_concap_demand_dial_dops = {
 100         NULL, /* set this first entry to something like &isdn_net_start_xmit,
 101                  but the entry part of the current isdn_net_start_xmit must be
 102                  separated first. */
 103         /* no connection control for demand dial semantics */
 104         NULL,
 105         NULL,
 106 };
 107
 108 /* The following should better go into a dedicated source file such that
 109    this sourcefile does not need to include any protocol specific header
 110    files. For now:
 111    */
 112 struct concap_proto * isdn_concap_new( int encap )
 113 {
 114         switch ( encap ) {
 115         case ISDN_NET_ENCAP_X25IFACE:
 116                 return isdn_x25iface_proto_new();
 117         }
 118         return NULL;
 119 }