/* *	"LAPB via ethernet" driver release 001 * *	This code REQUIRES 2.1.15 or higher/ NET3.038 * *	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. * *	This is a "pseudo" network driver to allow LAPB over Ethernet. * *	This driver can use any ethernet destination address, and can be  *	limited to accept frames from one dedicated ethernet card only. * *	History *	LAPBETH 001	Jonathan Naylor		Cloned from bpqether.c *	2000-10-29	Henner Eisen	lapb_data_indication() return status. *	2000-11-14	Henner Eisen	dev_hold/put, NETDEV_GOING_DOWN support */ #include <linux/errno.h>#include <linux/types.h>#include <linux/socket.h>#include <linux/in.h>#include <linux/kernel.h>#include <linux/string.h>#include <linux/net.h>#include <linux/inet.h>#include <linux/netdevice.h>#include <linux/if_arp.h>#include <linux/skbuff.h>#include <net/sock.h>#include <asm/system.h>#include <asm/uaccess.h>#include <linux/mm.h>#include <linux/interrupt.h>#include <linux/notifier.h>#include <linux/stat.h>#include <linux/netfilter.h>#include <linux/module.h>#include <linux/lapb.h>#include <linux/init.h> #include <net/x25device.h> static char bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; /* If this number is made larger, check that the temporary string buffer * in lapbeth_new_device is large enough to store the probe device name.*/#define MAXLAPBDEV 100 struct lapbethdev {	struct list_head	node;	struct net_device	*ethdev;	/* link to ethernet device */	struct net_device	*axdev;		/* lapbeth device (lapb#) */	struct net_device_stats stats;		/* some statistics */}; static struct list_head lapbeth_devices = LIST_HEAD_INIT(lapbeth_devices); /* ------------------------------------------------------------------------ */ /* *	Get the LAPB device for the ethernet device */static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev){	struct lapbethdev *lapbeth; 	list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) {		if (lapbeth->ethdev == dev) 			return lapbeth;	}	return NULL;} static __inline__ int dev_is_ethdev(struct net_device *dev){	return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);} /* ------------------------------------------------------------------------ */ /* *	Receive a LAPB frame via an ethernet interface. */static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev){	int len, err;	struct lapbethdev *lapbeth; 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)		return NET_RX_DROP; 	if (!pskb_may_pull(skb, 2))		goto drop; 	rcu_read_lock();	lapbeth = lapbeth_get_x25_dev(dev);	if (!lapbeth)		goto drop_unlock;	if (!netif_running(lapbeth->axdev))		goto drop_unlock; 	lapbeth->stats.rx_packets++; 	len = skb->data[0] + skb->data[1] * 256;	lapbeth->stats.rx_bytes += len; 	skb_pull(skb, 2);	/* Remove the length bytes */	skb_trim(skb, len);	/* Set the length of the data */ 	if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {		printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);		goto drop_unlock;	}out:	rcu_read_unlock();	return 0;drop_unlock:	kfree_skb(skb);	goto out;drop:	kfree_skb(skb);	return 0;} static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb){	unsigned char *ptr; 	skb_push(skb, 1); 	if (skb_cow(skb, 1))		return NET_RX_DROP; 	ptr  = skb->data;	*ptr = 0x00; 	skb->protocol = x25_type_trans(skb, dev);	skb->dev->last_rx = jiffies;	return netif_rx(skb);} /* *	Send a LAPB frame via an ethernet interface */static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev){	int err = -ENODEV; 	/*	 * Just to be *really* sure not to send anything if the interface	 * is down, the ethernet device may have gone.	 */	if (!netif_running(dev)) {		goto drop;	} 	switch (skb->data[0]) {	case 0x00:		err = 0;		break;	case 0x01:		if ((err = lapb_connect_request(dev)) != LAPB_OK)			printk(KERN_ERR "lapbeth: lapb_connect_request "			       "error: %d\n", err);		goto drop_ok;	case 0x02:		if ((err = lapb_disconnect_request(dev)) != LAPB_OK)			printk(KERN_ERR "lapbeth: lapb_disconnect_request "			       "err: %d\n", err);		/* Fall thru */	default:		goto drop_ok;	} 	skb_pull(skb, 1); 	if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {		printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);		err = -ENOMEM;		goto drop;	}	err = 0;out:	return err;drop_ok:	err = 0;drop:	kfree_skb(skb);	goto out;} static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb){	struct lapbethdev *lapbeth = netdev_priv(ndev);	unsigned char *ptr;	struct net_device *dev;	int size = skb->len; 	skb->protocol = htons(ETH_P_X25); 	ptr = skb_push(skb, 2); 	*ptr++ = size % 256;	*ptr++ = size / 256; 	lapbeth->stats.tx_packets++;	lapbeth->stats.tx_bytes += size; 	skb->dev = dev = lapbeth->ethdev; 	dev->hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 	dev_queue_xmit(skb);} static void lapbeth_connected(struct net_device *dev, int reason){	unsigned char *ptr;	struct sk_buff *skb = dev_alloc_skb(1); 	if (!skb) {		printk(KERN_ERR "lapbeth: out of memory\n");		return;	} 	ptr  = skb_put(skb, 1);	*ptr = 0x01; 	skb->protocol = x25_type_trans(skb, dev);	skb->dev->last_rx = jiffies;	netif_rx(skb);} static void lapbeth_disconnected(struct net_device *dev, int reason){	unsigned char *ptr;	struct sk_buff *skb = dev_alloc_skb(1); 	if (!skb) {		printk(KERN_ERR "lapbeth: out of memory\n");		return;	} 	ptr  = skb_put(skb, 1);	*ptr = 0x02; 	skb->protocol = x25_type_trans(skb, dev);	skb->dev->last_rx = jiffies;	netif_rx(skb);} /* *	Statistics */static struct net_device_stats *lapbeth_get_stats(struct net_device *dev){	struct lapbethdev *lapbeth = netdev_priv(dev);	return &lapbeth->stats;} /* *	Set AX.25 callsign */static int lapbeth_set_mac_address(struct net_device *dev, void *addr){	struct sockaddr *sa = addr;	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);	return 0;}  static struct lapb_register_struct lapbeth_callbacks = {	.connect_confirmation    = lapbeth_connected,	.connect_indication      = lapbeth_connected,	.disconnect_confirmation = lapbeth_disconnected,	.disconnect_indication   = lapbeth_disconnected,	.data_indication         = lapbeth_data_indication,	.data_transmit           = lapbeth_data_transmit, }; /* * open/close a device */static int lapbeth_open(struct net_device *dev){	int err; 	if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {		printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);		return -ENODEV;	} 	netif_start_queue(dev);	return 0;} static int lapbeth_close(struct net_device *dev){	int err; 	netif_stop_queue(dev); 	if ((err = lapb_unregister(dev)) != LAPB_OK)		printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); 	return 0;} /* ------------------------------------------------------------------------ */ static void lapbeth_setup(struct net_device *dev){	dev->hard_start_xmit = lapbeth_xmit;	dev->open	     = lapbeth_open;	dev->stop	     = lapbeth_close;	dev->destructor	     = free_netdev;	dev->set_mac_address = lapbeth_set_mac_address;	dev->get_stats	     = lapbeth_get_stats;	dev->type            = ARPHRD_X25;	dev->hard_header_len = 3;	dev->mtu             = 1000;	dev->addr_len        = 0;	SET_MODULE_OWNER(dev);} /* *	Setup a new device. */static int lapbeth_new_device(struct net_device *dev){	struct net_device *ndev;	struct lapbethdev *lapbeth;	int rc = -ENOMEM; 	ASSERT_RTNL(); 	ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 			   lapbeth_setup);	if (!ndev)		goto out; 	lapbeth = netdev_priv(ndev);	lapbeth->axdev = ndev; 	dev_hold(dev);	lapbeth->ethdev = dev; 	rc = dev_alloc_name(ndev, ndev->name);	if (rc < 0) 		goto fail; 	rc = -EIO;	if (register_netdevice(ndev))		goto fail; 	list_add_rcu(&lapbeth->node, &lapbeth_devices);	rc = 0;out:	return rc;fail:	dev_put(dev);	free_netdev(ndev);	kfree(lapbeth);	goto out;} /* *	Free a lapb network device. */static void lapbeth_free_device(struct lapbethdev *lapbeth){	dev_put(lapbeth->ethdev);	list_del_rcu(&lapbeth->node);	unregister_netdevice(lapbeth->axdev);} /* *	Handle device status changes. * * Called from notifier with RTNL held. */static int lapbeth_device_event(struct notifier_block *this,				unsigned long event, void *ptr){	struct lapbethdev *lapbeth;	struct net_device *dev = ptr; 	if (!dev_is_ethdev(dev))		return NOTIFY_DONE; 	switch (event) {	case NETDEV_UP:		/* New ethernet device -> new LAPB interface	 */		if (lapbeth_get_x25_dev(dev) == NULL)			lapbeth_new_device(dev);		break;	case NETDEV_DOWN:			/* ethernet device closed -> close LAPB interface */		lapbeth = lapbeth_get_x25_dev(dev);		if (lapbeth) 			dev_close(lapbeth->axdev);		break;	case NETDEV_UNREGISTER:		/* ethernet device disappears -> remove LAPB interface */		lapbeth = lapbeth_get_x25_dev(dev);		if (lapbeth)			lapbeth_free_device(lapbeth);		break;	} 	return NOTIFY_DONE;} /* ------------------------------------------------------------------------ */ static struct packet_type lapbeth_packet_type = {	.type = __constant_htons(ETH_P_DEC),	.func = lapbeth_rcv,}; static struct notifier_block lapbeth_dev_notifier = {	.notifier_call = lapbeth_device_event,}; static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n"; static int __init lapbeth_init_driver(void){	dev_add_pack(&lapbeth_packet_type); 	register_netdevice_notifier(&lapbeth_dev_notifier); 	printk(banner); 	return 0;}module_init(lapbeth_init_driver); static void __exit lapbeth_cleanup_driver(void){	struct lapbethdev *lapbeth;	struct list_head *entry, *tmp; 	dev_remove_pack(&lapbeth_packet_type);	unregister_netdevice_notifier(&lapbeth_dev_notifier); 	rtnl_lock();	list_for_each_safe(entry, tmp, &lapbeth_devices) {		lapbeth = list_entry(entry, struct lapbethdev, node); 		unregister_netdevice(lapbeth->axdev);	}	rtnl_unlock();}module_exit(lapbeth_cleanup_driver); MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");MODULE_LICENSE("GPL");