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				/*				 *	X.25 Packet Layer release 002				 *				 *	This is ALPHA test software. This code may break your machine, randomly fail to work with new 				 *	releases, misbehave and/or generally screw up. It might even work. 				 *				 *	This code REQUIRES 2.1.15 or higher				 *				 *	This module:				 *		This module is free software; you can redistribute it and/or				 *		modify it under the terms of the GNU General Public License				 *		as published by the Free Software Foundation; either version				 *		2 of the License, or (at your option) any later version.				 *				 *	History				 *	X.25 001	Jonathan Naylor	Started coding.				 *      2000-09-04	Henner Eisen	Prevent freeing a dangling skb.				 */								#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 	/* For TIOCINQ/OUTQ */				#include 				#include 				#include 				#include 				#include 				#include 								static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *neigh)				{					struct sock *sk;					unsigned short frametype;					unsigned int lci;									frametype = skb->data[2];				        lci = ((skb->data[0] data[1] 									/*					 *	LCI of zero is always for us, and its always a link control					 *	frame.					 */					if (lci == 0) {						x25_link_control(skb, neigh, frametype);						return 0;					}									/*					 *	Find an existing socket.					 */					if ((sk = x25_find_socket(lci, neigh)) != NULL) {						int queued = 1;										skb->h.raw = skb->data;						bh_lock_sock(sk);						if (!sk->lock.users) {							queued = x25_process_rx_frame(sk, skb);						} else {							sk_add_backlog(sk, skb);						}						bh_unlock_sock(sk);						return queued;					}									/*					 *	Is is a Call Request ? if so process it.					 */					if (frametype == X25_CALL_REQUEST)						return x25_rx_call_request(skb, neigh, lci);									/*					 *	Its not a Call Request, nor is it a control frame.					 *      Let caller throw it away.					 */				/*					x25_transmit_clear_request(neigh, lci, 0x0D);				*/					printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);									return 0;				}								int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)				{					struct x25_neigh *neigh;					int queued;									skb->sk = NULL;									/*					 *	Packet received from unrecognised device, throw it away.					 */					if ((neigh = x25_get_neigh(dev)) == NULL) {						printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);						kfree_skb(skb);						return 0;					}									switch (skb->data[0]) {						case 0x00:							skb_pull(skb, 1);							queued = x25_receive_data(skb, neigh);							if( ! queued )								/* We need to free the skb ourselves because								 * net_bh() won't care about our return code.								 */								kfree_skb(skb);							return 0;										case 0x01:							x25_link_established(neigh);							kfree_skb(skb);							return 0;										case 0x02:							x25_link_terminated(neigh);							kfree_skb(skb);							return 0;										case 0x03:							kfree_skb(skb);							return 0;										default:							kfree_skb(skb);							return 0;					}				}								int x25_llc_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)				{					struct x25_neigh *neigh;									skb->sk = NULL;									/*					 *	Packet received from unrecognised device, throw it away.					 */					if ((neigh = x25_get_neigh(dev)) == NULL) {						printk(KERN_DEBUG "X.25: unknown_neighbour - %s\n", dev->name);						kfree_skb(skb);						return 0;					}									return x25_receive_data(skb, neigh);				}								void x25_establish_link(struct x25_neigh *neigh)				{					struct sk_buff *skb;					unsigned char *ptr;									switch (neigh->dev->type) {						case ARPHRD_X25:							if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {								printk(KERN_ERR "x25_dev: out of memory\n");								return;							}							ptr  = skb_put(skb, 1);							*ptr = 0x01;							break;								#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)						case ARPHRD_ETHER:							return;				#endif						default:							return;					}									skb->protocol = htons(ETH_P_X25);					skb->dev      = neigh->dev;									dev_queue_xmit(skb);				}								void x25_terminate_link(struct x25_neigh *neigh)				{					struct sk_buff *skb;					unsigned char *ptr;									switch (neigh->dev->type) {						case ARPHRD_X25:							if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {								printk(KERN_ERR "x25_dev: out of memory\n");								return;							}							ptr  = skb_put(skb, 1);							*ptr = 0x02;							break;								#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)						case ARPHRD_ETHER:							return;				#endif						default:							return;					}									skb->protocol = htons(ETH_P_X25);					skb->dev      = neigh->dev;									dev_queue_xmit(skb);				}								void x25_send_frame(struct sk_buff *skb, struct x25_neigh *neigh)				{					unsigned char *dptr;									skb->nh.raw = skb->data;									switch (neigh->dev->type) {						case ARPHRD_X25:							dptr  = skb_push(skb, 1);							*dptr = 0x00;							break;								#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)						case ARPHRD_ETHER:							kfree_skb(skb);							return;				#endif						default:							kfree_skb(skb);							return;					}									skb->protocol = htons(ETH_P_X25);					skb->dev      = neigh->dev;									dev_queue_xmit(skb);				}