331 lines
9.9 KiB
C
331 lines
9.9 KiB
C
/* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
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*
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* Linux ISDN subsystem, X.25 related functions
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*
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* This software may be used and distributed according to the terms
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* of the GNU General Public License, incorporated herein by reference.
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*
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* stuff needed to support the Linux X.25 PLP code on top of devices that
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* can provide a lab_b service using the concap_proto mechanism.
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* This module supports a network interface which provides lapb_sematics
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* -- as defined in Documentation/networking/x25-iface.txt -- to
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* the upper layer and assumes that the lower layer provides a reliable
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* data link service by means of the concap_device_ops callbacks.
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*
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* Only protocol specific stuff goes here. Device specific stuff
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* goes to another -- device related -- concap_proto support source file.
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*
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*/
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/* #include <linux/isdn.h> */
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#include <linux/netdevice.h>
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#include <linux/concap.h>
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#include <linux/wanrouter.h>
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#include <net/x25device.h>
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#include "isdn_x25iface.h"
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/* for debugging messages not to cause an oops when device pointer is NULL*/
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#define MY_DEVNAME(dev) ( (dev) ? (dev)->name : "DEVICE UNSPECIFIED" )
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typedef struct isdn_x25iface_proto_data {
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int magic;
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enum wan_states state;
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/* Private stuff, not to be accessed via proto_data. We provide the
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other storage for the concap_proto instance here as well,
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enabling us to allocate both with just one kmalloc(): */
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struct concap_proto priv;
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} ix25_pdata_t;
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/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */
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static void isdn_x25iface_proto_del( struct concap_proto * );
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static int isdn_x25iface_proto_close( struct concap_proto * );
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static int isdn_x25iface_proto_restart( struct concap_proto *,
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struct net_device *,
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struct concap_device_ops *);
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static int isdn_x25iface_xmit( struct concap_proto *, struct sk_buff * );
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static int isdn_x25iface_receive( struct concap_proto *, struct sk_buff * );
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static int isdn_x25iface_connect_ind( struct concap_proto * );
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static int isdn_x25iface_disconn_ind( struct concap_proto * );
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static struct concap_proto_ops ix25_pops = {
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&isdn_x25iface_proto_new,
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&isdn_x25iface_proto_del,
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&isdn_x25iface_proto_restart,
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&isdn_x25iface_proto_close,
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&isdn_x25iface_xmit,
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&isdn_x25iface_receive,
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&isdn_x25iface_connect_ind,
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&isdn_x25iface_disconn_ind
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};
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/* error message helper function */
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static void illegal_state_warn( unsigned state, unsigned char firstbyte)
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{
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printk( KERN_WARNING "isdn_x25iface: firstbyte %x illegal in"
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"current state %d\n",firstbyte, state );
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}
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/* check protocol data field for consistency */
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static int pdata_is_bad( ix25_pdata_t * pda ){
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if( pda && pda -> magic == ISDN_X25IFACE_MAGIC ) return 0;
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printk( KERN_WARNING
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"isdn_x25iface_xxx: illegal pointer to proto data\n" );
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return 1;
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}
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/* create a new x25 interface protocol instance
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*/
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struct concap_proto * isdn_x25iface_proto_new(void)
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{
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ix25_pdata_t * tmp = kmalloc(sizeof(ix25_pdata_t),GFP_KERNEL);
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IX25DEBUG("isdn_x25iface_proto_new\n");
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if( tmp ){
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tmp -> magic = ISDN_X25IFACE_MAGIC;
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tmp -> state = WAN_UNCONFIGURED;
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/* private data space used to hold the concap_proto data.
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Only to be accessed via the returned pointer */
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spin_lock_init(&tmp->priv.lock);
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tmp -> priv.dops = NULL;
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tmp -> priv.net_dev = NULL;
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tmp -> priv.pops = &ix25_pops;
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tmp -> priv.flags = 0;
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tmp -> priv.proto_data = tmp;
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return( &(tmp -> priv) );
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}
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return NULL;
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};
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/* close the x25iface encapsulation protocol
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*/
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static int isdn_x25iface_proto_close(struct concap_proto *cprot){
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ix25_pdata_t *tmp;
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int ret = 0;
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ulong flags;
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if( ! cprot ){
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printk( KERN_ERR "isdn_x25iface_proto_close: "
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"invalid concap_proto pointer\n" );
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return -1;
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}
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IX25DEBUG( "isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot -> net_dev) );
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spin_lock_irqsave(&cprot->lock, flags);
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cprot -> dops = NULL;
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cprot -> net_dev = NULL;
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tmp = cprot -> proto_data;
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if( pdata_is_bad( tmp ) ){
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ret = -1;
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} else {
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tmp -> state = WAN_UNCONFIGURED;
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}
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spin_unlock_irqrestore(&cprot->lock, flags);
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return ret;
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}
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/* Delete the x25iface encapsulation protocol instance
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*/
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static void isdn_x25iface_proto_del(struct concap_proto *cprot){
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ix25_pdata_t * tmp;
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IX25DEBUG( "isdn_x25iface_proto_del \n" );
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if( ! cprot ){
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printk( KERN_ERR "isdn_x25iface_proto_del: "
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"concap_proto pointer is NULL\n" );
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return;
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}
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tmp = cprot -> proto_data;
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if( tmp == NULL ){
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printk( KERN_ERR "isdn_x25iface_proto_del: inconsistent "
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"proto_data pointer (maybe already deleted?)\n");
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return;
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}
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/* close if the protocol is still open */
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if( cprot -> dops ) isdn_x25iface_proto_close(cprot);
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/* freeing the storage should be sufficient now. But some additional
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settings might help to catch wild pointer bugs */
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tmp -> magic = 0;
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cprot -> proto_data = NULL;
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kfree( tmp );
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return;
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}
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/* (re-)initialize the data structures for x25iface encapsulation
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*/
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static int isdn_x25iface_proto_restart(struct concap_proto *cprot,
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struct net_device *ndev,
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struct concap_device_ops *dops)
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{
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ix25_pdata_t * pda = cprot -> proto_data ;
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ulong flags;
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IX25DEBUG( "isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev) );
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if ( pdata_is_bad( pda ) ) return -1;
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if( !( dops && dops -> data_req && dops -> connect_req
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&& dops -> disconn_req ) ){
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printk( KERN_WARNING "isdn_x25iface_restart: required dops"
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" missing\n" );
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isdn_x25iface_proto_close(cprot);
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return -1;
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}
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spin_lock_irqsave(&cprot->lock, flags);
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cprot -> net_dev = ndev;
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cprot -> pops = &ix25_pops;
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cprot -> dops = dops;
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pda -> state = WAN_DISCONNECTED;
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spin_unlock_irqrestore(&cprot->lock, flags);
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return 0;
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}
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/* deliver a dl_data frame received from i4l HL driver to the network layer
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*/
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static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb)
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{
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IX25DEBUG( "isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev) );
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if ( ( (ix25_pdata_t*) (cprot->proto_data) )
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-> state == WAN_CONNECTED ){
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if( skb_push(skb, 1)){
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skb -> data[0]=0x00;
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skb->protocol = x25_type_trans(skb, cprot->net_dev);
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netif_rx(skb);
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return 0;
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}
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}
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printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev) );
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dev_kfree_skb(skb);
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return -1;
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}
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/* a connection set up is indicated by lower layer
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*/
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static int isdn_x25iface_connect_ind(struct concap_proto *cprot)
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{
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struct sk_buff * skb;
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enum wan_states *state_p
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= &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state);
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IX25DEBUG( "isdn_x25iface_connect_ind %s \n"
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, MY_DEVNAME(cprot->net_dev) );
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if( *state_p == WAN_UNCONFIGURED ){
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printk(KERN_WARNING
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"isdn_x25iface_connect_ind while unconfigured %s\n"
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, MY_DEVNAME(cprot->net_dev) );
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return -1;
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}
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*state_p = WAN_CONNECTED;
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skb = dev_alloc_skb(1);
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if( skb ){
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*( skb_put(skb, 1) ) = 0x01;
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skb->protocol = x25_type_trans(skb, cprot->net_dev);
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netif_rx(skb);
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return 0;
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} else {
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printk(KERN_WARNING "isdn_x25iface_connect_ind: "
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" out of memory -- disconnecting\n");
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cprot -> dops -> disconn_req(cprot);
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return -1;
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}
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}
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/* a disconnect is indicated by lower layer
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*/
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static int isdn_x25iface_disconn_ind(struct concap_proto *cprot)
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{
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struct sk_buff *skb;
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enum wan_states *state_p
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= &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state);
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IX25DEBUG( "isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot -> net_dev) );
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if( *state_p == WAN_UNCONFIGURED ){
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printk(KERN_WARNING
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"isdn_x25iface_disconn_ind while unconfigured\n");
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return -1;
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}
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if(! cprot -> net_dev) return -1;
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*state_p = WAN_DISCONNECTED;
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skb = dev_alloc_skb(1);
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if( skb ){
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*( skb_put(skb, 1) ) = 0x02;
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skb->protocol = x25_type_trans(skb, cprot->net_dev);
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netif_rx(skb);
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return 0;
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} else {
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printk(KERN_WARNING "isdn_x25iface_disconn_ind:"
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" out of memory\n");
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return -1;
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}
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}
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/* process a frame handed over to us from linux network layer. First byte
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semantics as defined in Documentation/networking/x25-iface.txt
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*/
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static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb)
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{
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unsigned char firstbyte = skb->data[0];
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enum wan_states *state = &((ix25_pdata_t*)cprot->proto_data)->state;
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int ret = 0;
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IX25DEBUG( "isdn_x25iface_xmit: %s first=%x state=%d \n", MY_DEVNAME(cprot -> net_dev), firstbyte, *state );
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switch ( firstbyte ){
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case 0x00: /* dl_data request */
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if( *state == WAN_CONNECTED ){
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skb_pull(skb, 1);
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cprot -> net_dev -> trans_start = jiffies;
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ret = ( cprot -> dops -> data_req(cprot, skb) );
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/* prepare for future retransmissions */
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if( ret ) skb_push(skb,1);
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return ret;
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}
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illegal_state_warn( *state, firstbyte );
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break;
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case 0x01: /* dl_connect request */
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if( *state == WAN_DISCONNECTED ){
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*state = WAN_CONNECTING;
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ret = cprot -> dops -> connect_req(cprot);
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if(ret){
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/* reset state and notify upper layer about
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* immidiatly failed attempts */
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isdn_x25iface_disconn_ind(cprot);
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}
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} else {
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illegal_state_warn( *state, firstbyte );
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}
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break;
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case 0x02: /* dl_disconnect request */
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switch ( *state ){
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case WAN_DISCONNECTED:
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/* Should not happen. However, give upper layer a
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chance to recover from inconstistency but don't
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trust the lower layer sending the disconn_confirm
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when already disconnected */
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printk(KERN_WARNING "isdn_x25iface_xmit: disconnect "
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" requested while disconnected\n" );
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isdn_x25iface_disconn_ind(cprot);
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break; /* prevent infinite loops */
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case WAN_CONNECTING:
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case WAN_CONNECTED:
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*state = WAN_DISCONNECTED;
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cprot -> dops -> disconn_req(cprot);
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break;
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default:
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illegal_state_warn( *state, firstbyte );
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}
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break;
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case 0x03: /* changing lapb parameters requested */
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printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb"
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" options not yet supported\n");
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break;
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default:
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printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal"
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" first byte %x ignored:\n", firstbyte);
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}
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dev_kfree_skb(skb);
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return 0;
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}
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