/* a disconnect is indicated by lower layer 
 */
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 -> mac.raw = skb -> data;
		skb -> dev  = cprot -> net_dev;
		skb -> protocol = htons(ETH_P_X25);
		skb -> pkt_type = PACKET_HOST;
		netif_rx(skb);
		return 0;
	} else {
		printk(KERN_WARNING "isdn_x25iface_disconn_ind:"
		       " out of memory\n");
		return -1;
	}
}

/* (re-)initialize the data structures for x25iface encapsulation
 */
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;
	}
	save_flags(flags);
	cli();  /* avoid races with incoming events calling pops methods while
		 cprot members are inconsistent */  
	cprot -> net_dev = ndev;
	cprot -> pops = &ix25_pops;
	cprot -> dops = dops;
	pda -> state = WAN_DISCONNECTED;
	restore_flags(flags);
	return 0;
}

/* close the x25iface encapsulation protocol 
 */
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) );
	save_flags(flags);
	cli();  /* avoid races with incoming events calling pops methods while
		 cprot members are inconsistent */  
	cprot -> dops    = NULL;
	cprot -> net_dev = NULL;
	tmp = cprot -> proto_data;
	if( pdata_is_bad( tmp ) ){
		ret = -1;
	} else {
		tmp -> state = WAN_UNCONFIGURED;
	}
	restore_flags(flags);

	return ret;
}

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 X25_IFACE_DATA:
		if (*state == WAN_CONNECTED) {
			skb_pull(skb, 1);
			cprot->net_dev->trans_start = jiffies;
			ret = (cprot->dops->data_req(cprot, skb));
			
			if (ret) skb_push(skb, 1);
			return ret;
		}
		illegal_state_warn(*state, firstbyte);
		break;
	case X25_IFACE_CONNECT:
		if (*state == WAN_DISCONNECTED) {
			*state = WAN_CONNECTING;
			ret = cprot->dops->connect_req(cprot);
			if (ret) {
				isdn_x25iface_disconn_ind(cprot);
			}
		} else {
			illegal_state_warn(*state, firstbyte);
		}
		break;
	case X25_IFACE_DISCONNECT:
		switch (*state) {
		case WAN_DISCONNECTED:
			printk(KERN_WARNING "isdn_x25iface_xmit: disconnect "
			       " requested while disconnected\n");
			isdn_x25iface_disconn_ind(cprot);
			break; 
		case WAN_CONNECTING:
		case WAN_CONNECTED:
			*state = WAN_DISCONNECTED;
			cprot->dops->disconn_req(cprot);
			break;
		default:
			illegal_state_warn(*state, firstbyte);
		}
		break;
	case X25_IFACE_PARAMS:
		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;
}

/* deliver a dl_data frame received from i4l HL driver to the network layer 
 */
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 ){
		skb -> dev = cprot -> net_dev;
		skb -> protocol = htons(ETH_P_X25);
		skb -> pkt_type = PACKET_HOST;
		if( skb_push(skb, 1)){
			skb -> data[0]=0x00;
			skb -> mac.raw = skb -> data;
			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;
}