[linux-2.6-block.git] / drivers / net / wan / lapbether.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	"LAPB via ethernet" driver release 001
 *
 *	This code REQUIRES 2.1.15 or higher/ NET3.038
 *
 *	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
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/slab.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 <linux/uaccess.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/stat.h>
#include <linux/module.h>
#include <linux/lapb.h>
#include <linux/init.h>

#include <net/x25device.h>

static const u8 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#) */
	bool			up;
	spinlock_t		up_lock;	/* Protects "up" */
	struct sk_buff_head	rx_queue;
	struct napi_struct	napi;
};

static LIST_HEAD(lapbeth_devices);

static void lapbeth_connected(struct net_device *dev, int reason);
static void lapbeth_disconnected(struct net_device *dev, int reason);

/* ------------------------------------------------------------------------ */

/*	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, lockdep_rtnl_is_held()) {
		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);
}

/* ------------------------------------------------------------------------ */

static int lapbeth_napi_poll(struct napi_struct *napi, int budget)
{
	struct lapbethdev *lapbeth = container_of(napi, struct lapbethdev,
						  napi);
	struct sk_buff *skb;
	int processed = 0;

	for (; processed < budget; ++processed) {
		skb = skb_dequeue(&lapbeth->rx_queue);
		if (!skb)
			break;
		netif_receive_skb_core(skb);
	}

	if (processed < budget)
		napi_complete(napi);

	return processed;
}

/*	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 (dev_net(dev) != &init_net)
		goto drop;

	skb = skb_share_check(skb, GFP_ATOMIC);
	if (!skb)
		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_rcu;
	spin_lock_bh(&lapbeth->up_lock);
	if (!lapbeth->up)
		goto drop_unlock;

	len = skb->data[0] + skb->data[1] * 256;
	dev->stats.rx_packets++;
	dev->stats.rx_bytes += len;

	skb_pull(skb, 2);	/* Remove the length bytes */
	skb_trim(skb, len);	/* Set the length of the data */

	err = lapb_data_received(lapbeth->axdev, skb);
	if (err != LAPB_OK) {
		printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
		goto drop_unlock;
	}
out:
	spin_unlock_bh(&lapbeth->up_lock);
	rcu_read_unlock();
	return 0;
drop_unlock:
	kfree_skb(skb);
	goto out;
drop_unlock_rcu:
	rcu_read_unlock();
drop:
	kfree_skb(skb);
	return 0;
}

static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
{
	struct lapbethdev *lapbeth = netdev_priv(dev);
	unsigned char *ptr;

	if (skb_cow(skb, 1)) {
		kfree_skb(skb);
		return NET_RX_DROP;
	}

	skb_push(skb, 1);

	ptr  = skb->data;
	*ptr = X25_IFACE_DATA;

	skb->protocol = x25_type_trans(skb, dev);

	skb_queue_tail(&lapbeth->rx_queue, skb);
	napi_schedule(&lapbeth->napi);
	return NET_RX_SUCCESS;
}

/*	Send a LAPB frame via an ethernet interface
 */
static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
				struct net_device *dev)
{
	struct lapbethdev *lapbeth = netdev_priv(dev);
	int err;

	spin_lock_bh(&lapbeth->up_lock);
	if (!lapbeth->up)
		goto drop;

	/* There should be a pseudo header of 1 byte added by upper layers.
	 * Check to make sure it is there before reading it.
	 */
	if (skb->len < 1)
		goto drop;

	switch (skb->data[0]) {
	case X25_IFACE_DATA:
		break;
	case X25_IFACE_CONNECT:
		err = lapb_connect_request(dev);
		if (err == LAPB_CONNECTED)
			lapbeth_connected(dev, LAPB_OK);
		else if (err != LAPB_OK)
			pr_err("lapb_connect_request error: %d\n", err);
		goto drop;
	case X25_IFACE_DISCONNECT:
		err = lapb_disconnect_request(dev);
		if (err == LAPB_NOTCONNECTED)
			lapbeth_disconnected(dev, LAPB_OK);
		else if (err != LAPB_OK)
			pr_err("lapb_disconnect_request err: %d\n", err);
		fallthrough;
	default:
		goto drop;
	}

	skb_pull(skb, 1);

	err = lapb_data_request(dev, skb);
	if (err != LAPB_OK) {
		pr_err("lapb_data_request error - %d\n", err);
		goto drop;
	}
out:
	spin_unlock_bh(&lapbeth->up_lock);
	return NETDEV_TX_OK;
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;

	ptr = skb_push(skb, 2);

	*ptr++ = size % 256;
	*ptr++ = size / 256;

	ndev->stats.tx_packets++;
	ndev->stats.tx_bytes += size;

	skb->dev = dev = lapbeth->ethdev;

	skb->protocol = htons(ETH_P_DEC);

	skb_reset_network_header(skb);

	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)
{
	struct lapbethdev *lapbeth = netdev_priv(dev);
	unsigned char *ptr;
	struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC);

	if (!skb)
		return;

	ptr  = skb_put(skb, 1);
	*ptr = X25_IFACE_CONNECT;

	skb->protocol = x25_type_trans(skb, dev);

	skb_queue_tail(&lapbeth->rx_queue, skb);
	napi_schedule(&lapbeth->napi);
}

static void lapbeth_disconnected(struct net_device *dev, int reason)
{
	struct lapbethdev *lapbeth = netdev_priv(dev);
	unsigned char *ptr;
	struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC);

	if (!skb)
		return;

	ptr  = skb_put(skb, 1);
	*ptr = X25_IFACE_DISCONNECT;

	skb->protocol = x25_type_trans(skb, dev);

	skb_queue_tail(&lapbeth->rx_queue, skb);
	napi_schedule(&lapbeth->napi);
}

/*	Set AX.25 callsign
 */
static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
{
	struct sockaddr *sa = addr;

	dev_addr_set(dev, sa->sa_data);
	return 0;
}

static const 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)
{
	struct lapbethdev *lapbeth = netdev_priv(dev);
	int err;

	napi_enable(&lapbeth->napi);

	err = lapb_register(dev, &lapbeth_callbacks);
	if (err != LAPB_OK) {
		napi_disable(&lapbeth->napi);
		pr_err("lapb_register error: %d\n", err);
		return -ENODEV;
	}

	spin_lock_bh(&lapbeth->up_lock);
	lapbeth->up = true;
	spin_unlock_bh(&lapbeth->up_lock);

	return 0;
}

static int lapbeth_close(struct net_device *dev)
{
	struct lapbethdev *lapbeth = netdev_priv(dev);
	int err;

	spin_lock_bh(&lapbeth->up_lock);
	lapbeth->up = false;
	spin_unlock_bh(&lapbeth->up_lock);

	err = lapb_unregister(dev);
	if (err != LAPB_OK)
		pr_err("lapb_unregister error: %d\n", err);

	napi_disable(&lapbeth->napi);

	return 0;
}

/* ------------------------------------------------------------------------ */

static const struct net_device_ops lapbeth_netdev_ops = {
	.ndo_open	     = lapbeth_open,
	.ndo_stop	     = lapbeth_close,
	.ndo_start_xmit	     = lapbeth_xmit,
	.ndo_set_mac_address = lapbeth_set_mac_address,
};

static void lapbeth_setup(struct net_device *dev)
{
	dev->netdev_ops	     = &lapbeth_netdev_ops;
	dev->needs_free_netdev = true;
	dev->type            = ARPHRD_X25;
	dev->hard_header_len = 0;
	dev->mtu             = 1000;
	dev->addr_len        = 0;
}

/*	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();

	if (dev->type != ARPHRD_ETHER)
		return -EINVAL;

	ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", NET_NAME_UNKNOWN,
			    lapbeth_setup);
	if (!ndev)
		goto out;

	/* When transmitting data:
	 * first this driver removes a pseudo header of 1 byte,
	 * then the lapb module prepends an LAPB header of at most 3 bytes,
	 * then this driver prepends a length field of 2 bytes,
	 * then the underlying Ethernet device prepends its own header.
	 */
	ndev->needed_headroom = -1 + 3 + 2 + dev->hard_header_len
					   + dev->needed_headroom;
	ndev->needed_tailroom = dev->needed_tailroom;

	lapbeth = netdev_priv(ndev);
	lapbeth->axdev = ndev;

	dev_hold(dev);
	lapbeth->ethdev = dev;

	lapbeth->up = false;
	spin_lock_init(&lapbeth->up_lock);

	skb_queue_head_init(&lapbeth->rx_queue);
	netif_napi_add_weight(ndev, &lapbeth->napi, lapbeth_napi_poll, 16);

	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);
	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 = netdev_notifier_info_to_dev(ptr);

	if (dev_net(dev) != &init_net)
		return NOTIFY_DONE;

	if (!dev_is_ethdev(dev) && !lapbeth_get_x25_dev(dev))
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UP:
		/* New ethernet device -> new LAPB interface	 */
		if (!lapbeth_get_x25_dev(dev))
			lapbeth_new_device(dev);
		break;
	case NETDEV_GOING_DOWN:
		/* ethernet device closes -> 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 __read_mostly = {
	.type = cpu_to_be16(ETH_P_DEC),
	.func = lapbeth_rcv,
};

static struct notifier_block lapbeth_dev_notifier = {
	.notifier_call = lapbeth_device_event,
};

static const char banner[] __initconst =
	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);

		dev_put(lapbeth->ethdev);
		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");
Commit	Line	Data
ee5d8f4d	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* "LAPB via ethernet" driver release 001
	4	*
	5	* This code REQUIRES 2.1.15 or higher/ NET3.038
	6	*
1da177e4 LT	7	* This is a "pseudo" network driver to allow LAPB over Ethernet.
1da177e4 LT	8	*
2e350780	9	* This driver can use any ethernet destination address, and can be
1da177e4 LT	10	* limited to accept frames from one dedicated ethernet card only.
	11	*
	12	* History
	13	* LAPBETH 001 Jonathan Naylor Cloned from bpqether.c
	14	* 2000-10-29 Henner Eisen lapb_data_indication() return status.
	15	* 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support
	16	*/
	17
23efcb73 JP	18	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23efcb73 JP	19
1da177e4 LT	20	#include <linux/errno.h>
	21	#include <linux/types.h>
	22	#include <linux/socket.h>
	23	#include <linux/in.h>
5a0e3ad6	24	#include <linux/slab.h>
1da177e4 LT	25	#include <linux/kernel.h>
	26	#include <linux/string.h>
	27	#include <linux/net.h>
	28	#include <linux/inet.h>
	29	#include <linux/netdevice.h>
	30	#include <linux/if_arp.h>
	31	#include <linux/skbuff.h>
	32	#include <net/sock.h>
7c0f6ba6	33	#include <linux/uaccess.h>
1da177e4 LT	34	#include <linux/mm.h>
	35	#include <linux/interrupt.h>
	36	#include <linux/notifier.h>
	37	#include <linux/stat.h>
1da177e4 LT	38	#include <linux/module.h>
	39	#include <linux/lapb.h>
	40	#include <linux/init.h>
	41
	42	#include <net/x25device.h>
	43
dcfc5d78	44	static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
1da177e4 LT	45
1da177e4 LT	46	/* If this number is made larger, check that the temporary string buffer
4f9893c7 PL	47	* in lapbeth_new_device is large enough to store the probe device name.
4f9893c7 PL	48	*/
1da177e4 LT	49	#define MAXLAPBDEV 100
	50
	51	struct lapbethdev {
	52	struct list_head node;
	53	struct net_device ethdev; / link to ethernet device */
	54	struct net_device axdev; / lapbeth device (lapb#) */
5acd0cfb XH	55	bool up;
5acd0cfb XH	56	spinlock_t up_lock; /* Protects "up" */
514e1150 XH	57	struct sk_buff_head rx_queue;
514e1150 XH	58	struct napi_struct napi;
1da177e4 LT	59	};
1da177e4 LT	60
293a3839	61	static LIST_HEAD(lapbeth_devices);
1da177e4	62
3b0c860f XH	63	static void lapbeth_connected(struct net_device *dev, int reason);
	64	static void lapbeth_disconnected(struct net_device *dev, int reason);
	65
1da177e4 LT	66	/* ------------------------------------------------------------------------ */
1da177e4 LT	67
4f9893c7	68	/* Get the LAPB device for the ethernet device
1da177e4 LT	69	*/
	70	static struct lapbethdev lapbeth_get_x25_dev(struct net_device dev)
	71	{
	72	struct lapbethdev *lapbeth;
	73
93ad0f96	74	list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node, lockdep_rtnl_is_held()) {
2e350780	75	if (lapbeth->ethdev == dev)
1da177e4 LT	76	return lapbeth;
	77	}
	78	return NULL;
	79	}
	80
	81	static __inline__ int dev_is_ethdev(struct net_device *dev)
	82	{
	83	return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
	84	}
	85
	86	/* ------------------------------------------------------------------------ */
	87
514e1150 XH	88	static int lapbeth_napi_poll(struct napi_struct *napi, int budget)
	89	{
	90	struct lapbethdev *lapbeth = container_of(napi, struct lapbethdev,
	91	napi);
	92	struct sk_buff *skb;
	93	int processed = 0;
	94
	95	for (; processed < budget; ++processed) {
	96	skb = skb_dequeue(&lapbeth->rx_queue);
	97	if (!skb)
	98	break;
	99	netif_receive_skb_core(skb);
	100	}
	101
	102	if (processed < budget)
	103	napi_complete(napi);
	104
	105	return processed;
	106	}
	107
4f9893c7	108	/* Receive a LAPB frame via an ethernet interface.
1da177e4	109	*/
63a2bb15 PL	110	static int lapbeth_rcv(struct sk_buff skb, struct net_device dev,
63a2bb15 PL	111	struct packet_type ptype, struct net_device orig_dev)
1da177e4 LT	112	{
	113	int len, err;
	114	struct lapbethdev *lapbeth;
	115
c346dca1	116	if (dev_net(dev) != &init_net)
e730c155 EB	117	goto drop;
e730c155 EB	118
a61bebc7 PL	119	skb = skb_share_check(skb, GFP_ATOMIC);
a61bebc7 PL	120	if (!skb)
1da177e4 LT	121	return NET_RX_DROP;
	122
	123	if (!pskb_may_pull(skb, 2))
	124	goto drop;
	125
	126	rcu_read_lock();
	127	lapbeth = lapbeth_get_x25_dev(dev);
	128	if (!lapbeth)
5acd0cfb XH	129	goto drop_unlock_rcu;
	130	spin_lock_bh(&lapbeth->up_lock);
	131	if (!lapbeth->up)
1da177e4 LT	132	goto drop_unlock;
1da177e4 LT	133
1da177e4	134	len = skb->data[0] + skb->data[1] * 256;
ea2ebaf8 SH	135	dev->stats.rx_packets++;
ea2ebaf8 SH	136	dev->stats.rx_bytes += len;
1da177e4 LT	137
	138	skb_pull(skb, 2); /* Remove the length bytes */
	139	skb_trim(skb, len); /* Set the length of the data */
	140
a61bebc7 PL	141	err = lapb_data_received(lapbeth->axdev, skb);
a61bebc7 PL	142	if (err != LAPB_OK) {
1da177e4 LT	143	printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
	144	goto drop_unlock;
	145	}
	146	out:
5acd0cfb	147	spin_unlock_bh(&lapbeth->up_lock);
1da177e4 LT	148	rcu_read_unlock();
	149	return 0;
	150	drop_unlock:
	151	kfree_skb(skb);
	152	goto out;
5acd0cfb XH	153	drop_unlock_rcu:
5acd0cfb XH	154	rcu_read_unlock();
1da177e4 LT	155	drop:
	156	kfree_skb(skb);
	157	return 0;
	158	}
	159
	160	static int lapbeth_data_indication(struct net_device dev, struct sk_buff skb)
	161	{
514e1150	162	struct lapbethdev *lapbeth = netdev_priv(dev);
1da177e4 LT	163	unsigned char *ptr;
1da177e4 LT	164
8754e137 XH	165	if (skb_cow(skb, 1)) {
8754e137 XH	166	kfree_skb(skb);
1da177e4	167	return NET_RX_DROP;
8754e137 XH	168	}
	169
	170	skb_push(skb, 1);
1da177e4 LT	171
1da177e4 LT	172	ptr = skb->data;
4d99503e	173	*ptr = X25_IFACE_DATA;
1da177e4 LT	174
1da177e4 LT	175	skb->protocol = x25_type_trans(skb, dev);
514e1150 XH	176
	177	skb_queue_tail(&lapbeth->rx_queue, skb);
	178	napi_schedule(&lapbeth->napi);
	179	return NET_RX_SUCCESS;
1da177e4 LT	180	}
1da177e4 LT	181
4f9893c7	182	/* Send a LAPB frame via an ethernet interface
1da177e4	183	*/
d71a6749	184	static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
c564c049	185	struct net_device *dev)
1da177e4	186	{
5acd0cfb	187	struct lapbethdev *lapbeth = netdev_priv(dev);
d77eeb70	188	int err;
1da177e4	189
5acd0cfb XH	190	spin_lock_bh(&lapbeth->up_lock);
5acd0cfb XH	191	if (!lapbeth->up)
1da177e4	192	goto drop;
1da177e4	193
c7ca03c2 XH	194	/* There should be a pseudo header of 1 byte added by upper layers.
	195	* Check to make sure it is there before reading it.
	196	*/
	197	if (skb->len < 1)
	198	goto drop;
	199
1da177e4	200	switch (skb->data[0]) {
4d99503e	201	case X25_IFACE_DATA:
1da177e4	202	break;
4d99503e	203	case X25_IFACE_CONNECT:
3b0c860f XH	204	err = lapb_connect_request(dev);
	205	if (err == LAPB_CONNECTED)
	206	lapbeth_connected(dev, LAPB_OK);
	207	else if (err != LAPB_OK)
23efcb73	208	pr_err("lapb_connect_request error: %d\n", err);
d77eeb70	209	goto drop;
4d99503e	210	case X25_IFACE_DISCONNECT:
3b0c860f XH	211	err = lapb_disconnect_request(dev);
	212	if (err == LAPB_NOTCONNECTED)
	213	lapbeth_disconnected(dev, LAPB_OK);
	214	else if (err != LAPB_OK)
23efcb73	215	pr_err("lapb_disconnect_request err: %d\n", err);
df561f66	216	fallthrough;
1da177e4	217	default:
d77eeb70	218	goto drop;
1da177e4 LT	219	}
	220
	221	skb_pull(skb, 1);
	222
a61bebc7 PL	223	err = lapb_data_request(dev, skb);
a61bebc7 PL	224	if (err != LAPB_OK) {
23efcb73	225	pr_err("lapb_data_request error - %d\n", err);
1da177e4 LT	226	goto drop;
1da177e4 LT	227	}
1da177e4	228	out:
5acd0cfb	229	spin_unlock_bh(&lapbeth->up_lock);
d77eeb70	230	return NETDEV_TX_OK;
1da177e4 LT	231	drop:
	232	kfree_skb(skb);
	233	goto out;
	234	}
	235
	236	static void lapbeth_data_transmit(struct net_device ndev, struct sk_buff skb)
	237	{
	238	struct lapbethdev *lapbeth = netdev_priv(ndev);
	239	unsigned char *ptr;
	240	struct net_device *dev;
	241	int size = skb->len;
	242
1da177e4 LT	243	ptr = skb_push(skb, 2);
	244
	245	*ptr++ = size % 256;
	246	*ptr++ = size / 256;
	247
ea2ebaf8 SH	248	ndev->stats.tx_packets++;
ea2ebaf8 SH	249	ndev->stats.tx_bytes += size;
1da177e4 LT	250
	251	skb->dev = dev = lapbeth->ethdev;
	252
83f9a9c8 XH	253	skb->protocol = htons(ETH_P_DEC);
83f9a9c8 XH	254
91244d10 XH	255	skb_reset_network_header(skb);
91244d10 XH	256
0c4e8581	257	dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
1da177e4 LT	258
	259	dev_queue_xmit(skb);
	260	}
	261
	262	static void lapbeth_connected(struct net_device *dev, int reason)
	263	{
514e1150	264	struct lapbethdev *lapbeth = netdev_priv(dev);
1da177e4	265	unsigned char *ptr;
514e1150	266	struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC \| __GFP_NOMEMALLOC);
1da177e4	267
d5e686e8	268	if (!skb)
1da177e4	269	return;
1da177e4 LT	270
1da177e4 LT	271	ptr = skb_put(skb, 1);
4d99503e	272	*ptr = X25_IFACE_CONNECT;
1da177e4 LT	273
1da177e4 LT	274	skb->protocol = x25_type_trans(skb, dev);
514e1150 XH	275
	276	skb_queue_tail(&lapbeth->rx_queue, skb);
	277	napi_schedule(&lapbeth->napi);
1da177e4 LT	278	}
	279
	280	static void lapbeth_disconnected(struct net_device *dev, int reason)
	281	{
514e1150	282	struct lapbethdev *lapbeth = netdev_priv(dev);
1da177e4	283	unsigned char *ptr;
514e1150	284	struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC \| __GFP_NOMEMALLOC);
1da177e4	285
d5e686e8	286	if (!skb)
1da177e4	287	return;
1da177e4 LT	288
1da177e4 LT	289	ptr = skb_put(skb, 1);
4d99503e	290	*ptr = X25_IFACE_DISCONNECT;
1da177e4 LT	291
1da177e4 LT	292	skb->protocol = x25_type_trans(skb, dev);
514e1150 XH	293
	294	skb_queue_tail(&lapbeth->rx_queue, skb);
	295	napi_schedule(&lapbeth->napi);
1da177e4 LT	296	}
1da177e4 LT	297
4f9893c7	298	/* Set AX.25 callsign
1da177e4 LT	299	*/
	300	static int lapbeth_set_mac_address(struct net_device dev, void addr)
	301	{
	302	struct sockaddr *sa = addr;
5bc5f5f2	303
ea52a0b5	304	dev_addr_set(dev, sa->sa_data);
1da177e4 LT	305	return 0;
	306	}
	307
d97a077a	308	static const struct lapb_register_struct lapbeth_callbacks = {
1da177e4 LT	309	.connect_confirmation = lapbeth_connected,
	310	.connect_indication = lapbeth_connected,
	311	.disconnect_confirmation = lapbeth_disconnected,
	312	.disconnect_indication = lapbeth_disconnected,
	313	.data_indication = lapbeth_data_indication,
	314	.data_transmit = lapbeth_data_transmit,
1da177e4 LT	315	};
1da177e4 LT	316
4f9893c7	317	/* open/close a device
1da177e4 LT	318	*/
	319	static int lapbeth_open(struct net_device *dev)
	320	{
5acd0cfb	321	struct lapbethdev *lapbeth = netdev_priv(dev);
1da177e4 LT	322	int err;
1da177e4 LT	323
514e1150 XH	324	napi_enable(&lapbeth->napi);
514e1150 XH	325
a61bebc7 PL	326	err = lapb_register(dev, &lapbeth_callbacks);
a61bebc7 PL	327	if (err != LAPB_OK) {
3faf7e14	328	napi_disable(&lapbeth->napi);
23efcb73	329	pr_err("lapb_register error: %d\n", err);
1da177e4 LT	330	return -ENODEV;
	331	}
	332
5acd0cfb XH	333	spin_lock_bh(&lapbeth->up_lock);
	334	lapbeth->up = true;
	335	spin_unlock_bh(&lapbeth->up_lock);
	336
1da177e4 LT	337	return 0;
	338	}
	339
	340	static int lapbeth_close(struct net_device *dev)
	341	{
5acd0cfb	342	struct lapbethdev *lapbeth = netdev_priv(dev);
1da177e4 LT	343	int err;
1da177e4 LT	344
5acd0cfb XH	345	spin_lock_bh(&lapbeth->up_lock);
	346	lapbeth->up = false;
	347	spin_unlock_bh(&lapbeth->up_lock);
	348
a61bebc7 PL	349	err = lapb_unregister(dev);
a61bebc7 PL	350	if (err != LAPB_OK)
23efcb73	351	pr_err("lapb_unregister error: %d\n", err);
1da177e4	352
514e1150 XH	353	napi_disable(&lapbeth->napi);
514e1150 XH	354
1da177e4 LT	355	return 0;
	356	}
	357
	358	/* ------------------------------------------------------------------------ */
	359
39549b1e SH	360	static const struct net_device_ops lapbeth_netdev_ops = {
	361	.ndo_open = lapbeth_open,
	362	.ndo_stop = lapbeth_close,
	363	.ndo_start_xmit = lapbeth_xmit,
	364	.ndo_set_mac_address = lapbeth_set_mac_address,
	365	};
	366
1da177e4 LT	367	static void lapbeth_setup(struct net_device *dev)
1da177e4 LT	368	{
39549b1e	369	dev->netdev_ops = &lapbeth_netdev_ops;
cf124db5	370	dev->needs_free_netdev = true;
1da177e4	371	dev->type = ARPHRD_X25;
c7ca03c2	372	dev->hard_header_len = 0;
1da177e4 LT	373	dev->mtu = 1000;
1da177e4 LT	374	dev->addr_len = 0;
1da177e4 LT	375	}
1da177e4 LT	376
4f9893c7	377	/* Setup a new device.
1da177e4 LT	378	*/
	379	static int lapbeth_new_device(struct net_device *dev)
	380	{
	381	struct net_device *ndev;
	382	struct lapbethdev *lapbeth;
	383	int rc = -ENOMEM;
	384
	385	ASSERT_RTNL();
	386
9eed321c ED	387	if (dev->type != ARPHRD_ETHER)
	388	return -EINVAL;
	389
c835a677 TG	390	ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", NET_NAME_UNKNOWN,
c835a677 TG	391	lapbeth_setup);
1da177e4 LT	392	if (!ndev)
	393	goto out;
	394
9dc829a1 XH	395	/* When transmitting data:
	396	* first this driver removes a pseudo header of 1 byte,
	397	* then the lapb module prepends an LAPB header of at most 3 bytes,
	398	* then this driver prepends a length field of 2 bytes,
	399	* then the underlying Ethernet device prepends its own header.
	400	*/
c7ca03c2 XH	401	ndev->needed_headroom = -1 + 3 + 2 + dev->hard_header_len
c7ca03c2 XH	402	+ dev->needed_headroom;
1ee39c14	403	ndev->needed_tailroom = dev->needed_tailroom;
9dc829a1	404
1da177e4 LT	405	lapbeth = netdev_priv(ndev);
	406	lapbeth->axdev = ndev;
	407
	408	dev_hold(dev);
	409	lapbeth->ethdev = dev;
	410
5acd0cfb XH	411	lapbeth->up = false;
	412	spin_lock_init(&lapbeth->up_lock);
	413
514e1150	414	skb_queue_head_init(&lapbeth->rx_queue);
6f83cb8c	415	netif_napi_add_weight(ndev, &lapbeth->napi, lapbeth_napi_poll, 16);
514e1150	416
1da177e4 LT	417	rc = -EIO;
	418	if (register_netdevice(ndev))
	419	goto fail;
	420
	421	list_add_rcu(&lapbeth->node, &lapbeth_devices);
	422	rc = 0;
	423	out:
	424	return rc;
	425	fail:
	426	dev_put(dev);
	427	free_netdev(ndev);
1da177e4 LT	428	goto out;
	429	}
	430
4f9893c7	431	/* Free a lapb network device.
1da177e4 LT	432	*/
	433	static void lapbeth_free_device(struct lapbethdev *lapbeth)
	434	{
	435	dev_put(lapbeth->ethdev);
	436	list_del_rcu(&lapbeth->node);
	437	unregister_netdevice(lapbeth->axdev);
	438	}
	439
4f9893c7	440	/* Handle device status changes.
1da177e4 LT	441	*
	442	* Called from notifier with RTNL held.
	443	*/
	444	static int lapbeth_device_event(struct notifier_block *this,
	445	unsigned long event, void *ptr)
	446	{
	447	struct lapbethdev *lapbeth;
351638e7	448	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1da177e4	449
c346dca1	450	if (dev_net(dev) != &init_net)
e9dc8653 EB	451	return NOTIFY_DONE;
e9dc8653 EB	452
531705a7	453	if (!dev_is_ethdev(dev) && !lapbeth_get_x25_dev(dev))
1da177e4 LT	454	return NOTIFY_DONE;
	455
	456	switch (event) {
	457	case NETDEV_UP:
	458	/* New ethernet device -> new LAPB interface */
d4985960	459	if (!lapbeth_get_x25_dev(dev))
1da177e4 LT	460	lapbeth_new_device(dev);
1da177e4 LT	461	break;
536e1004 XH	462	case NETDEV_GOING_DOWN:
536e1004 XH	463	/* ethernet device closes -> close LAPB interface */
1da177e4	464	lapbeth = lapbeth_get_x25_dev(dev);
2e350780	465	if (lapbeth)
1da177e4 LT	466	dev_close(lapbeth->axdev);
	467	break;
	468	case NETDEV_UNREGISTER:
	469	/* ethernet device disappears -> remove LAPB interface */
	470	lapbeth = lapbeth_get_x25_dev(dev);
	471	if (lapbeth)
	472	lapbeth_free_device(lapbeth);
	473	break;
	474	}
	475
	476	return NOTIFY_DONE;
	477	}
	478
	479	/* ------------------------------------------------------------------------ */
	480
7546dd97	481	static struct packet_type lapbeth_packet_type __read_mostly = {
09640e63	482	.type = cpu_to_be16(ETH_P_DEC),
1da177e4 LT	483	.func = lapbeth_rcv,
	484	};
	485
	486	static struct notifier_block lapbeth_dev_notifier = {
	487	.notifier_call = lapbeth_device_event,
	488	};
	489
81b700b1	490	static const char banner[] __initconst =
5ee0d593	491	KERN_INFO "LAPB Ethernet driver version 0.02\n";
1da177e4 LT	492
	493	static int __init lapbeth_init_driver(void)
	494	{
	495	dev_add_pack(&lapbeth_packet_type);
	496
	497	register_netdevice_notifier(&lapbeth_dev_notifier);
	498
	499	printk(banner);
	500
	501	return 0;
	502	}
	503	module_init(lapbeth_init_driver);
	504
	505	static void __exit lapbeth_cleanup_driver(void)
	506	{
	507	struct lapbethdev *lapbeth;
	508	struct list_head entry, tmp;
	509
	510	dev_remove_pack(&lapbeth_packet_type);
	511	unregister_netdevice_notifier(&lapbeth_dev_notifier);
	512
	513	rtnl_lock();
	514	list_for_each_safe(entry, tmp, &lapbeth_devices) {
	515	lapbeth = list_entry(entry, struct lapbethdev, node);
	516
e544ff00	517	dev_put(lapbeth->ethdev);
1da177e4 LT	518	unregister_netdevice(lapbeth->axdev);
	519	}
	520	rtnl_unlock();
	521	}
	522	module_exit(lapbeth_cleanup_driver);
	523
	524	MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
	525	MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
	526	MODULE_LICENSE("GPL");