drivers/isdn/i4l/isdn_concap.c

   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
  42 static 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 *) netdev_priv(ndev))->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
  61 static int isdn_concap_dl_connect_req(struct concap_proto *concap)
  62 {
  63         struct net_device *ndev = concap->net_dev;
  64         isdn_net_local *lp = netdev_priv(ndev);
  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
  74 static 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
  82 struct concap_device_ops isdn_concap_reliable_dl_dops = {
  83         .data_req = &isdn_concap_dl_data_req,
  84         .connect_req = &isdn_concap_dl_connect_req,
  85         .disconn_req = &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 */
  92 struct 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 }