drivers/isdn/i4l/isdn_x25iface.c - linux - Git at Google

 /* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
  *
  * Linux ISDN subsystem, X.25 related functions
  *
  * This software may be used and distributed according to the terms
  * of the GNU General Public License, incorporated herein by reference.
  *
  * stuff needed to support the Linux X.25 PLP code on top of devices that
  * can provide a lab_b service using the concap_proto mechanism.
  * This module supports a network interface which provides lapb_sematics
  * -- as defined in Documentation/networking/x25-iface.txt -- to
  * the upper layer and assumes that the lower layer provides a reliable
  * data link service by means of the concap_device_ops callbacks.
  *
  * Only protocol specific stuff goes here. Device specific stuff
  * goes to another -- device related -- concap_proto support source file.
  *
  */

 /* #include <linux/isdn.h> */
 #include <linux/netdevice.h>
 #include <linux/concap.h>
 #include <linux/wanrouter.h>
 #include <net/x25device.h>
 #include "isdn_x25iface.h"

 /* for debugging messages not to cause an oops when device pointer is NULL*/
 #define MY_DEVNAME(dev)  ( (dev) ? (dev)->name : "DEVICE UNSPECIFIED" )


 typedef struct isdn_x25iface_proto_data {
 	int magic;
 	enum wan_states state;
 	/* Private stuff, not to be accessed via proto_data. We provide the
 	   other storage for the concap_proto instance here as well,
 	   enabling us to allocate both with just one kmalloc(): */
 	struct concap_proto priv;
 } ix25_pdata_t;


 /* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */
 static void isdn_x25iface_proto_del( struct concap_proto * );
 static int isdn_x25iface_proto_close( struct concap_proto * );
 static int isdn_x25iface_proto_restart( struct concap_proto *,
 					struct net_device *,
 					struct concap_device_ops *);
 static int isdn_x25iface_xmit( struct concap_proto *, struct sk_buff * );
 static int isdn_x25iface_receive( struct concap_proto *, struct sk_buff * );
 static int isdn_x25iface_connect_ind( struct concap_proto * );
 static int isdn_x25iface_disconn_ind( struct concap_proto * );


 static struct concap_proto_ops ix25_pops = {
 	&isdn_x25iface_proto_new,
 	&isdn_x25iface_proto_del,
 	&isdn_x25iface_proto_restart,
 	&isdn_x25iface_proto_close,
 	&isdn_x25iface_xmit,
 	&isdn_x25iface_receive,
 	&isdn_x25iface_connect_ind,
 	&isdn_x25iface_disconn_ind
 };

 /* error message helper function */
 static void illegal_state_warn( unsigned state, unsigned char firstbyte)
 {
 	printk( KERN_WARNING "isdn_x25iface: firstbyte %x illegal in"
 		"current state %d\n",firstbyte, state );
 }

 /* check protocol data field for consistency */
 static int pdata_is_bad( ix25_pdata_t * pda ){

 	if( pda  &&  pda -> magic == ISDN_X25IFACE_MAGIC ) return 0;
 	printk( KERN_WARNING
 		"isdn_x25iface_xxx: illegal pointer to proto data\n" );
 	return 1;
 }

 /* create a new x25 interface protocol instance
  */
 struct concap_proto * isdn_x25iface_proto_new(void)
 {
 	ix25_pdata_t * tmp = kmalloc(sizeof(ix25_pdata_t),GFP_KERNEL);
 	IX25DEBUG("isdn_x25iface_proto_new\n");
 	if( tmp ){
 		tmp -> magic = ISDN_X25IFACE_MAGIC;
 		tmp -> state = WAN_UNCONFIGURED;
 		/* private data space used to hold the concap_proto data.
 		   Only to be accessed via the returned pointer */
 		spin_lock_init(&tmp->priv.lock);
 		tmp -> priv.dops       = NULL;
 		tmp -> priv.net_dev    = NULL;
 		tmp -> priv.pops       = &ix25_pops;
 		tmp -> priv.flags      = 0;
 		tmp -> priv.proto_data = tmp;
 		return( &(tmp -> priv) );
 	}
 	return NULL;
 };

 /* close the x25iface encapsulation protocol
  */
 static int isdn_x25iface_proto_close(struct concap_proto *cprot){

 	ix25_pdata_t *tmp;
         int ret = 0;
 	ulong flags;

 	if( ! cprot ){
 		printk( KERN_ERR "isdn_x25iface_proto_close: "
 			"invalid concap_proto pointer\n" );
 		return -1;
 	}
 	IX25DEBUG( "isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot -> net_dev) );
 	spin_lock_irqsave(&cprot->lock, flags);
 	cprot -> dops    = NULL;
 	cprot -> net_dev = NULL;
 	tmp = cprot -> proto_data;
 	if( pdata_is_bad( tmp ) ){
 		ret = -1;
 	} else {
 		tmp -> state = WAN_UNCONFIGURED;
 	}
 	spin_unlock_irqrestore(&cprot->lock, flags);
 	return ret;
 }

 /* Delete the x25iface encapsulation protocol instance
  */
 static void isdn_x25iface_proto_del(struct concap_proto *cprot){

 	ix25_pdata_t * tmp;

 	IX25DEBUG( "isdn_x25iface_proto_del \n" );
 	if( ! cprot ){
 		printk( KERN_ERR "isdn_x25iface_proto_del: "
 			"concap_proto pointer is NULL\n" );
 		return;
 	}
 	tmp = cprot -> proto_data;
 	if( tmp == NULL ){
 		printk( KERN_ERR "isdn_x25iface_proto_del: inconsistent "
 			"proto_data pointer (maybe already deleted?)\n");
 		return;
 	}
 	/* close if the protocol is still open */
 	if( cprot -> dops ) isdn_x25iface_proto_close(cprot);
 	/* freeing the storage should be sufficient now. But some additional
 	   settings might help to catch wild pointer bugs */
 	tmp -> magic = 0;
 	cprot -> proto_data = NULL;

 	kfree( tmp );
 	return;
 }

 /* (re-)initialize the data structures for x25iface encapsulation
  */
 static int isdn_x25iface_proto_restart(struct concap_proto *cprot,
 					struct net_device *ndev,
 					struct concap_device_ops *dops)
 {
 	ix25_pdata_t * pda = cprot -> proto_data ;
 	ulong flags;

 	IX25DEBUG( "isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev) );

 	if ( pdata_is_bad( pda ) ) return -1;

 	if( !( dops  && dops -> data_req && dops -> connect_req
 	       && dops -> disconn_req )  ){
 		printk( KERN_WARNING "isdn_x25iface_restart: required dops"
 			" missing\n" );
 		isdn_x25iface_proto_close(cprot);
 		return -1;
 	}
 	spin_lock_irqsave(&cprot->lock, flags);
 	cprot -> net_dev = ndev;
 	cprot -> pops = &ix25_pops;
 	cprot -> dops = dops;
 	pda -> state = WAN_DISCONNECTED;
 	spin_unlock_irqrestore(&cprot->lock, flags);
 	return 0;
 }

 /* deliver a dl_data frame received from i4l HL driver to the network layer
  */
 static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb)
 {
   	IX25DEBUG( "isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev) );
 	if ( ( (ix25_pdata_t*) (cprot->proto_data) )
 	     -> state == WAN_CONNECTED ){
 		if( skb_push(skb, 1)){
 			skb -> data[0]=0x00;
 			skb->protocol = x25_type_trans(skb, cprot->net_dev);
 			netif_rx(skb);
 			return 0;
 		}
 	}
 	printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev) );
 	dev_kfree_skb(skb);
 	return -1;
 }

 /* a connection set up is indicated by lower layer
  */
 static int isdn_x25iface_connect_ind(struct concap_proto *cprot)
 {
 	struct sk_buff * skb = dev_alloc_skb(1);
 	enum wan_states *state_p
 	  = &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state);
 	IX25DEBUG( "isdn_x25iface_connect_ind %s \n"
 		   , MY_DEVNAME(cprot->net_dev) );
 	if( *state_p == WAN_UNCONFIGURED ){
 		printk(KERN_WARNING
 		       "isdn_x25iface_connect_ind while unconfigured %s\n"
 		       , MY_DEVNAME(cprot->net_dev) );
 		return -1;
 	}
 	*state_p = WAN_CONNECTED;
 	if( skb ){
 		*( skb_put(skb, 1) ) = 0x01;
 		skb->protocol = x25_type_trans(skb, cprot->net_dev);
 		netif_rx(skb);
 		return 0;
 	} else {
 		printk(KERN_WARNING "isdn_x25iface_connect_ind: "
 		       " out of memory -- disconnecting\n");
 		cprot -> dops -> disconn_req(cprot);
 		return -1;
 	}
 }

 /* a disconnect is indicated by lower layer
  */
 static int isdn_x25iface_disconn_ind(struct concap_proto *cprot)
 {
 	struct sk_buff *skb;
 	enum wan_states *state_p
 	  = &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state);
 	IX25DEBUG( "isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot -> net_dev) );
 	if( *state_p == WAN_UNCONFIGURED ){
 		printk(KERN_WARNING
 		       "isdn_x25iface_disconn_ind while unconfigured\n");
 		return -1;
 	}
 	if(! cprot -> net_dev) return -1;
 	*state_p = WAN_DISCONNECTED;
 	skb = dev_alloc_skb(1);
 	if( skb ){
 		*( skb_put(skb, 1) ) = 0x02;
 		skb->protocol = x25_type_trans(skb, cprot->net_dev);
 		netif_rx(skb);
 		return 0;
 	} else {
 		printk(KERN_WARNING "isdn_x25iface_disconn_ind:"
 		       " out of memory\n");
 		return -1;
 	}
 }

 /* process a frame handed over to us from linux network layer. First byte
    semantics as defined in Documentation/networking/x25-iface.txt
    */
 static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb)
 {
 	unsigned char firstbyte = skb->data[0];
 	enum wan_states *state = &((ix25_pdata_t*)cprot->proto_data)->state;
 	int ret = 0;
 	IX25DEBUG( "isdn_x25iface_xmit: %s first=%x state=%d \n", MY_DEVNAME(cprot -> net_dev), firstbyte, *state );
 	switch ( firstbyte ){
 	case 0x00: /* dl_data request */
 		if( *state == WAN_CONNECTED ){
 			skb_pull(skb, 1);
 			cprot -> net_dev -> trans_start = jiffies;
 			ret = ( cprot -> dops -> data_req(cprot, skb) );
 			/* prepare for future retransmissions */
 			if( ret ) skb_push(skb,1);
 			return ret;
 		}
 		illegal_state_warn( *state, firstbyte );
 		break;
 	case 0x01: /* dl_connect request */
 		if( *state == WAN_DISCONNECTED ){
 			*state = WAN_CONNECTING;
 		        ret = cprot -> dops -> connect_req(cprot);
 			if(ret){
 				/* reset state and notify upper layer about
 				 * immidiatly failed attempts */
 				isdn_x25iface_disconn_ind(cprot);
 			}
 		} else {
 			illegal_state_warn( *state, firstbyte );
 		}
 		break;
 	case 0x02: /* dl_disconnect request */
 		switch ( *state ){
 		case WAN_DISCONNECTED:
 			/* Should not happen. However, give upper layer a
 			   chance to recover from inconstistency  but don't
 			   trust the lower layer sending the disconn_confirm
 			   when already disconnected */
 			printk(KERN_WARNING "isdn_x25iface_xmit: disconnect "
 			       " requested while disconnected\n" );
 			isdn_x25iface_disconn_ind(cprot);
 			break; /* prevent infinite loops */
 		case WAN_CONNECTING:
 		case WAN_CONNECTED:
 			*state = WAN_DISCONNECTED;
 			cprot -> dops -> disconn_req(cprot);
 			break;
 		default:
 			illegal_state_warn( *state, firstbyte );
 		}
 		break;
 	case 0x03: /* changing lapb parameters requested */
 		printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb"
 		       " options not yet supported\n");
 		break;
 	default:
 		printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal"
 		       " first byte %x ignored:\n", firstbyte);
 	}
 	dev_kfree_skb(skb);
 	return 0;
 }
	/* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
	*
	* Linux ISDN subsystem, X.25 related functions
	*
	* This software may be used and distributed according to the terms
	* of the GNU General Public License, incorporated herein by reference.
	*
	* stuff needed to support the Linux X.25 PLP code on top of devices that
	* can provide a lab_b service using the concap_proto mechanism.
	* This module supports a network interface which provides lapb_sematics
	* -- as defined in Documentation/networking/x25-iface.txt -- to
	* the upper layer and assumes that the lower layer provides a reliable
	* data link service by means of the concap_device_ops callbacks.
	*
	* Only protocol specific stuff goes here. Device specific stuff
	* goes to another -- device related -- concap_proto support source file.
	*
	*/

	/* #include <linux/isdn.h> */
	#include <linux/netdevice.h>
	#include <linux/concap.h>
	#include <linux/wanrouter.h>
	#include <net/x25device.h>
	#include "isdn_x25iface.h"

	/* for debugging messages not to cause an oops when device pointer is NULL*/
	#define MY_DEVNAME(dev) ( (dev) ? (dev)->name : "DEVICE UNSPECIFIED" )


	typedef struct isdn_x25iface_proto_data {
	int magic;
	enum wan_states state;
	/* Private stuff, not to be accessed via proto_data. We provide the
	other storage for the concap_proto instance here as well,
	enabling us to allocate both with just one kmalloc(): */
	struct concap_proto priv;
	} ix25_pdata_t;



	/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */
	static void isdn_x25iface_proto_del( struct concap_proto * );
	static int isdn_x25iface_proto_close( struct concap_proto * );
	static int isdn_x25iface_proto_restart( struct concap_proto *,
	struct net_device *,
	struct concap_device_ops *);
	static int isdn_x25iface_xmit( struct concap_proto , struct sk_buff );
	static int isdn_x25iface_receive( struct concap_proto , struct sk_buff );
	static int isdn_x25iface_connect_ind( struct concap_proto * );
	static int isdn_x25iface_disconn_ind( struct concap_proto * );


	static struct concap_proto_ops ix25_pops = {
	&isdn_x25iface_proto_new,
	&isdn_x25iface_proto_del,
	&isdn_x25iface_proto_restart,
	&isdn_x25iface_proto_close,
	&isdn_x25iface_xmit,
	&isdn_x25iface_receive,
	&isdn_x25iface_connect_ind,
	&isdn_x25iface_disconn_ind
	};

	/* error message helper function */
	static void illegal_state_warn( unsigned state, unsigned char firstbyte)
	{
	printk( KERN_WARNING "isdn_x25iface: firstbyte %x illegal in"
	"current state %d\n",firstbyte, state );
	}

	/* check protocol data field for consistency */
	static int pdata_is_bad( ix25_pdata_t * pda ){

	if( pda && pda -> magic == ISDN_X25IFACE_MAGIC ) return 0;
	printk( KERN_WARNING
	"isdn_x25iface_xxx: illegal pointer to proto data\n" );
	return 1;
	}

	/* create a new x25 interface protocol instance
	*/
	struct concap_proto * isdn_x25iface_proto_new(void)
	{
	ix25_pdata_t * tmp = kmalloc(sizeof(ix25_pdata_t),GFP_KERNEL);
	IX25DEBUG("isdn_x25iface_proto_new\n");
	if( tmp ){
	tmp -> magic = ISDN_X25IFACE_MAGIC;
	tmp -> state = WAN_UNCONFIGURED;
	/* private data space used to hold the concap_proto data.
	Only to be accessed via the returned pointer */
	spin_lock_init(&tmp->priv.lock);
	tmp -> priv.dops = NULL;
	tmp -> priv.net_dev = NULL;
	tmp -> priv.pops = &ix25_pops;
	tmp -> priv.flags = 0;
	tmp -> priv.proto_data = tmp;
	return( &(tmp -> priv) );
	}
	return NULL;
	};

	/* close the x25iface encapsulation protocol
	*/
	static int isdn_x25iface_proto_close(struct concap_proto *cprot){

	ix25_pdata_t *tmp;
	int ret = 0;
	ulong flags;

	if( ! cprot ){
	printk( KERN_ERR "isdn_x25iface_proto_close: "
	"invalid concap_proto pointer\n" );
	return -1;
	}
	IX25DEBUG( "isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot -> net_dev) );
	spin_lock_irqsave(&cprot->lock, flags);
	cprot -> dops = NULL;
	cprot -> net_dev = NULL;
	tmp = cprot -> proto_data;
	if( pdata_is_bad( tmp ) ){
	ret = -1;
	} else {
	tmp -> state = WAN_UNCONFIGURED;
	}
	spin_unlock_irqrestore(&cprot->lock, flags);
	return ret;
	}

	/* Delete the x25iface encapsulation protocol instance
	*/
	static void isdn_x25iface_proto_del(struct concap_proto *cprot){

	ix25_pdata_t * tmp;

	IX25DEBUG( "isdn_x25iface_proto_del \n" );
	if( ! cprot ){
	printk( KERN_ERR "isdn_x25iface_proto_del: "
	"concap_proto pointer is NULL\n" );
	return;
	}
	tmp = cprot -> proto_data;
	if( tmp == NULL ){
	printk( KERN_ERR "isdn_x25iface_proto_del: inconsistent "
	"proto_data pointer (maybe already deleted?)\n");
	return;
	}
	/* close if the protocol is still open */
	if( cprot -> dops ) isdn_x25iface_proto_close(cprot);
	/* freeing the storage should be sufficient now. But some additional
	settings might help to catch wild pointer bugs */
	tmp -> magic = 0;
	cprot -> proto_data = NULL;

	kfree( tmp );
	return;
	}

	/* (re-)initialize the data structures for x25iface encapsulation
	*/
	static int isdn_x25iface_proto_restart(struct concap_proto *cprot,
	struct net_device *ndev,
	struct concap_device_ops *dops)
	{
	ix25_pdata_t * pda = cprot -> proto_data ;
	ulong flags;

	IX25DEBUG( "isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev) );

	if ( pdata_is_bad( pda ) ) return -1;

	if( !( dops && dops -> data_req && dops -> connect_req
	&& dops -> disconn_req ) ){
	printk( KERN_WARNING "isdn_x25iface_restart: required dops"
	" missing\n" );
	isdn_x25iface_proto_close(cprot);
	return -1;
	}
	spin_lock_irqsave(&cprot->lock, flags);
	cprot -> net_dev = ndev;
	cprot -> pops = &ix25_pops;
	cprot -> dops = dops;
	pda -> state = WAN_DISCONNECTED;
	spin_unlock_irqrestore(&cprot->lock, flags);
	return 0;
	}

	/* deliver a dl_data frame received from i4l HL driver to the network layer
	*/
	static int isdn_x25iface_receive(struct concap_proto cprot, struct sk_buff skb)
	{
	IX25DEBUG( "isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev) );
	if ( ( (ix25_pdata_t*) (cprot->proto_data) )
	-> state == WAN_CONNECTED ){
	if( skb_push(skb, 1)){
	skb -> data[0]=0x00;
	skb->protocol = x25_type_trans(skb, cprot->net_dev);
	netif_rx(skb);
	return 0;
	}
	}
	printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev) );
	dev_kfree_skb(skb);
	return -1;
	}

	/* a connection set up is indicated by lower layer
	*/
	static int isdn_x25iface_connect_ind(struct concap_proto *cprot)
	{
	struct sk_buff * skb = dev_alloc_skb(1);
	enum wan_states *state_p
	= &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state);
	IX25DEBUG( "isdn_x25iface_connect_ind %s \n"
	, MY_DEVNAME(cprot->net_dev) );
	if( *state_p == WAN_UNCONFIGURED ){
	printk(KERN_WARNING
	"isdn_x25iface_connect_ind while unconfigured %s\n"
	, MY_DEVNAME(cprot->net_dev) );
	return -1;
	}
	*state_p = WAN_CONNECTED;
	if( skb ){
	*( skb_put(skb, 1) ) = 0x01;
	skb->protocol = x25_type_trans(skb, cprot->net_dev);
	netif_rx(skb);
	return 0;
	} else {
	printk(KERN_WARNING "isdn_x25iface_connect_ind: "
	" out of memory -- disconnecting\n");
	cprot -> dops -> disconn_req(cprot);
	return -1;
	}
	}

	/* a disconnect is indicated by lower layer
	*/
	static int isdn_x25iface_disconn_ind(struct concap_proto *cprot)
	{
	struct sk_buff *skb;
	enum wan_states *state_p
	= &( ( (ix25_pdata_t*) (cprot->proto_data) ) -> state);
	IX25DEBUG( "isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot -> net_dev) );
	if( *state_p == WAN_UNCONFIGURED ){
	printk(KERN_WARNING
	"isdn_x25iface_disconn_ind while unconfigured\n");
	return -1;
	}
	if(! cprot -> net_dev) return -1;
	*state_p = WAN_DISCONNECTED;
	skb = dev_alloc_skb(1);
	if( skb ){
	*( skb_put(skb, 1) ) = 0x02;
	skb->protocol = x25_type_trans(skb, cprot->net_dev);
	netif_rx(skb);
	return 0;
	} else {
	printk(KERN_WARNING "isdn_x25iface_disconn_ind:"
	" out of memory\n");
	return -1;
	}
	}

	/* process a frame handed over to us from linux network layer. First byte
	semantics as defined in Documentation/networking/x25-iface.txt
	*/
	static int isdn_x25iface_xmit(struct concap_proto cprot, struct sk_buff skb)
	{
	unsigned char firstbyte = skb->data[0];
	enum wan_states state = &((ix25_pdata_t)cprot->proto_data)->state;
	int ret = 0;
	IX25DEBUG( "isdn_x25iface_xmit: %s first=%x state=%d \n", MY_DEVNAME(cprot -> net_dev), firstbyte, *state );
	switch ( firstbyte ){
	case 0x00: /* dl_data request */
	if( *state == WAN_CONNECTED ){
	skb_pull(skb, 1);
	cprot -> net_dev -> trans_start = jiffies;
	ret = ( cprot -> dops -> data_req(cprot, skb) );
	/* prepare for future retransmissions */
	if( ret ) skb_push(skb,1);
	return ret;
	}
	illegal_state_warn( *state, firstbyte );
	break;
	case 0x01: /* dl_connect request */
	if( *state == WAN_DISCONNECTED ){
	*state = WAN_CONNECTING;
	ret = cprot -> dops -> connect_req(cprot);
	if(ret){
	/* reset state and notify upper layer about
	* immidiatly failed attempts */
	isdn_x25iface_disconn_ind(cprot);
	}
	} else {
	illegal_state_warn( *state, firstbyte );
	}
	break;
	case 0x02: /* dl_disconnect request */
	switch ( *state ){
	case WAN_DISCONNECTED:
	/* Should not happen. However, give upper layer a
	chance to recover from inconstistency but don't
	trust the lower layer sending the disconn_confirm
	when already disconnected */
	printk(KERN_WARNING "isdn_x25iface_xmit: disconnect "
	" requested while disconnected\n" );
	isdn_x25iface_disconn_ind(cprot);
	break; /* prevent infinite loops */
	case WAN_CONNECTING:
	case WAN_CONNECTED:
	*state = WAN_DISCONNECTED;
	cprot -> dops -> disconn_req(cprot);
	break;
	default:
	illegal_state_warn( *state, firstbyte );
	}
	break;
	case 0x03: /* changing lapb parameters requested */
	printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb"
	" options not yet supported\n");
	break;
	default:
	printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal"
	" first byte %x ignored:\n", firstbyte);
	}
	dev_kfree_skb(skb);
	return 0;
	}