[thirdparty/linux.git] / drivers / net / hamradio / bpqether.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	G8BPQ compatible "AX.25 via ethernet" driver release 004
 *
 *	This code REQUIRES 2.0.0 or higher/ NET3.029
 *
 *	This is a "pseudo" network driver to allow AX.25 over Ethernet
 *	using G8BPQ encapsulation. It has been extracted from the protocol
 *	implementation because
 *
 *		- things got unreadable within the protocol stack
 *		- to cure the protocol stack from "feature-ism"
 *		- a protocol implementation shouldn't need to know on
 *		  which hardware it is running
 *		- user-level programs like the AX.25 utilities shouldn't
 *		  need to know about the hardware.
 *		- IP over ethernet encapsulated AX.25 was impossible
 *		- rxecho.c did not work
 *		- to have room for extensions
 *		- it just deserves to "live" as an own driver
 *
 *	This driver can use any ethernet destination address, and can be
 *	limited to accept frames from one dedicated ethernet card only.
 *
 *	Note that the driver sets up the BPQ devices automagically on
 *	startup or (if started before the "insmod" of an ethernet device)
 *	on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
 *	the ethernet device (in fact: as soon as another ethernet or bpq
 *	device gets "ifconfig"ured).
 *
 *	I have heard that several people are thinking of experiments
 *	with highspeed packet radio using existing ethernet cards.
 *	Well, this driver is prepared for this purpose, just add
 *	your tx key control and a txdelay / tailtime algorithm,
 *	probably some buffering, and /voila/...
 *
 *	History
 *	BPQ   001	Joerg(DL1BKE)		Extracted BPQ code from AX.25
 *						protocol stack and added my own
 *						yet existing patches
 *	BPQ   002	Joerg(DL1BKE)		Scan network device list on
 *						startup.
 *	BPQ   003	Joerg(DL1BKE)		Ethernet destination address
 *						and accepted source address
 *						can be configured by an ioctl()
 *						call.
 *						Fixed to match Linux networking
 *						changes - 2.1.15.
 *	BPQ   004	Joerg(DL1BKE)		Fixed to not lock up on ifconfig.
 */

#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/slab.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.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/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>

#include <net/ip.h>
#include <net/arp.h>
#include <net/net_namespace.h>

#include <linux/bpqether.h>

static const char banner[] __initconst = KERN_INFO \
	"AX.25: bpqether driver version 004\n";

static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
static int bpq_device_event(struct notifier_block *, unsigned long, void *);

static struct packet_type bpq_packet_type __read_mostly = {
	.type	= cpu_to_be16(ETH_P_BPQ),
	.func	= bpq_rcv,
};

static struct notifier_block bpq_dev_notifier = {
	.notifier_call = bpq_device_event,
};


struct bpqdev {
	struct list_head bpq_list;	/* list of bpq devices chain */
	struct net_device *ethdev;	/* link to ethernet device */
	struct net_device *axdev;	/* bpq device (bpq#) */
	char   dest_addr[6];		/* ether destination address */
	char   acpt_addr[6];		/* accept ether frames from this address only */
};

static LIST_HEAD(bpq_devices);

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


/*
 *	Get the ethernet device for a BPQ device
 */
static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
{
	struct bpqdev *bpq = netdev_priv(dev);

	return bpq ? bpq->ethdev : NULL;
}

/*
 *	Get the BPQ device for the ethernet device
 */
static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
{
	struct bpqdev *bpq;

	list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list,
				lockdep_rtnl_is_held()) {
		if (bpq->ethdev == dev)
			return bpq->axdev;
	}
	return NULL;
}

static inline int dev_is_ethdev(struct net_device *dev)
{
	return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
}

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


/*
 *	Receive an AX.25 frame via an ethernet interface.
 */
static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
{
	int len;
	char * ptr;
	struct ethhdr *eth;
	struct bpqdev *bpq;

	if (!net_eq(dev_net(dev), &init_net))
		goto drop;

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
		return NET_RX_DROP;

	if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
		goto drop;

	rcu_read_lock();
	dev = bpq_get_ax25_dev(dev);

	if (dev == NULL || !netif_running(dev)) 
		goto drop_unlock;

	/*
	 * if we want to accept frames from just one ethernet device
	 * we check the source address of the sender.
	 */

	bpq = netdev_priv(dev);

	eth = eth_hdr(skb);

	if (!(bpq->acpt_addr[0] & 0x01) &&
	    !ether_addr_equal(eth->h_source, bpq->acpt_addr))
		goto drop_unlock;

	if (skb_cow(skb, sizeof(struct ethhdr)))
		goto drop_unlock;

	len = skb->data[0] + skb->data[1] * 256 - 5;

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

	dev->stats.rx_packets++;
	dev->stats.rx_bytes += len;

	ptr = skb_push(skb, 1);
	*ptr = 0;

	skb->protocol = ax25_type_trans(skb, dev);
	netif_rx(skb);
unlock:

	rcu_read_unlock();

	return 0;
drop_unlock:
	kfree_skb(skb);
	goto unlock;

drop:
	kfree_skb(skb);
	return 0;
}

/*
 * 	Send an AX.25 frame via an ethernet interface
 */
static netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev)
{
	unsigned char *ptr;
	struct bpqdev *bpq;
	struct net_device *orig_dev;
	int size;

	if (skb->protocol == htons(ETH_P_IP))
		return ax25_ip_xmit(skb);

	/*
	 * Just to be *really* sure not to send anything if the interface
	 * is down, the ethernet device may have gone.
	 */
	if (!netif_running(dev)) {
		kfree_skb(skb);
		return NETDEV_TX_OK;
	}

	skb_pull(skb, 1);			/* Drop KISS byte */
	size = skb->len;

	/*
	 * We're about to mess with the skb which may still shared with the
	 * generic networking code so unshare and ensure it's got enough
	 * space for the BPQ headers.
	 */
	if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
		if (net_ratelimit())
			pr_err("bpqether: out of memory\n");
		kfree_skb(skb);

		return NETDEV_TX_OK;
	}

	ptr = skb_push(skb, 2);			/* Make space for length */

	*ptr++ = (size + 5) % 256;
	*ptr++ = (size + 5) / 256;

	bpq = netdev_priv(dev);

	orig_dev = dev;
	if ((dev = bpq_get_ether_dev(dev)) == NULL) {
		orig_dev->stats.tx_dropped++;
		kfree_skb(skb);
		return NETDEV_TX_OK;
	}

	skb->protocol = ax25_type_trans(skb, dev);
	skb_reset_network_header(skb);
	dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
	dev->stats.tx_packets++;
	dev->stats.tx_bytes+=skb->len;
  
	dev_queue_xmit(skb);
	netif_wake_queue(dev);
	return NETDEV_TX_OK;
}

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

    memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);

    return 0;
}

/*	Ioctl commands
 *
 *		SIOCSBPQETHOPT		reserved for enhancements
 *		SIOCSBPQETHADDR		set the destination and accepted
 *					source ethernet address (broadcast
 *					or multicast: accept all)
 */
static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
	struct bpqdev *bpq = netdev_priv(dev);
	struct bpq_req req;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	switch (cmd) {
		case SIOCSBPQETHOPT:
			if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
				return -EFAULT;
			switch (req.cmd) {
				case SIOCGBPQETHPARAM:
				case SIOCSBPQETHPARAM:
				default:
					return -EINVAL;
			}

			break;

		case SIOCSBPQETHADDR:
			if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
				return -EFAULT;
			if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
				return -EFAULT;
			break;

		default:
			return -EINVAL;
	}

	return 0;
}

/*
 * open/close a device
 */
static int bpq_open(struct net_device *dev)
{
	netif_start_queue(dev);
	return 0;
}

static int bpq_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}


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


/*
 *	Proc filesystem
 */
static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(RCU)
{
	int i = 1;
	struct bpqdev *bpqdev;

	rcu_read_lock();

	if (*pos == 0)
		return SEQ_START_TOKEN;
	
	list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
		if (i == *pos)
			return bpqdev;
	}
	return NULL;
}

static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct list_head *p;
	struct bpqdev *bpqdev = v;

	++*pos;

	if (v == SEQ_START_TOKEN)
		p = rcu_dereference(list_next_rcu(&bpq_devices));
	else
		p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list));

	return (p == &bpq_devices) ? NULL 
		: list_entry(p, struct bpqdev, bpq_list);
}

static void bpq_seq_stop(struct seq_file *seq, void *v)
	__releases(RCU)
{
	rcu_read_unlock();
}


static int bpq_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_puts(seq, 
			 "dev   ether      destination        accept from\n");
	else {
		const struct bpqdev *bpqdev = v;

		seq_printf(seq, "%-5s %-10s %pM  ",
			bpqdev->axdev->name, bpqdev->ethdev->name,
			bpqdev->dest_addr);

		if (is_multicast_ether_addr(bpqdev->acpt_addr))
			seq_printf(seq, "*\n");
		else
			seq_printf(seq, "%pM\n", bpqdev->acpt_addr);

	}
	return 0;
}

static const struct seq_operations bpq_seqops = {
	.start = bpq_seq_start,
	.next = bpq_seq_next,
	.stop = bpq_seq_stop,
	.show = bpq_seq_show,
};

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

static const struct net_device_ops bpq_netdev_ops = {
	.ndo_open	     = bpq_open,
	.ndo_stop	     = bpq_close,
	.ndo_start_xmit	     = bpq_xmit,
	.ndo_set_mac_address = bpq_set_mac_address,
	.ndo_do_ioctl	     = bpq_ioctl,
};

static void bpq_setup(struct net_device *dev)
{
	dev->netdev_ops	     = &bpq_netdev_ops;
	dev->needs_free_netdev = true;

	memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
	memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);

	dev->flags      = 0;
	dev->features	= NETIF_F_LLTX;	/* Allow recursion */

#if IS_ENABLED(CONFIG_AX25)
	dev->header_ops      = &ax25_header_ops;
#endif

	dev->type            = ARPHRD_AX25;
	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
	dev->mtu             = AX25_DEF_PACLEN;
	dev->addr_len        = AX25_ADDR_LEN;

}

/*
 *	Setup a new device.
 */
static int bpq_new_device(struct net_device *edev)
{
	int err;
	struct net_device *ndev;
	struct bpqdev *bpq;

	ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", NET_NAME_UNKNOWN,
			    bpq_setup);
	if (!ndev)
		return -ENOMEM;

		
	bpq = netdev_priv(ndev);
	dev_hold(edev);
	bpq->ethdev = edev;
	bpq->axdev = ndev;

	eth_broadcast_addr(bpq->dest_addr);
	eth_broadcast_addr(bpq->acpt_addr);

	err = register_netdevice(ndev);
	if (err)
		goto error;

	/* List protected by RTNL */
	list_add_rcu(&bpq->bpq_list, &bpq_devices);
	return 0;

 error:
	dev_put(edev);
	free_netdev(ndev);
	return err;
	
}

static void bpq_free_device(struct net_device *ndev)
{
	struct bpqdev *bpq = netdev_priv(ndev);

	dev_put(bpq->ethdev);
	list_del_rcu(&bpq->bpq_list);

	unregister_netdevice(ndev);
}

/*
 *	Handle device status changes.
 */
static int bpq_device_event(struct notifier_block *this,
			    unsigned long event, void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

	if (!net_eq(dev_net(dev), &init_net))
		return NOTIFY_DONE;

	if (!dev_is_ethdev(dev))
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UP:		/* new ethernet device -> new BPQ interface */
		if (bpq_get_ax25_dev(dev) == NULL)
			bpq_new_device(dev);
		break;

	case NETDEV_DOWN:	/* ethernet device closed -> close BPQ interface */
		if ((dev = bpq_get_ax25_dev(dev)) != NULL)
			dev_close(dev);
		break;

	case NETDEV_UNREGISTER:	/* ethernet device removed -> free BPQ interface */
		if ((dev = bpq_get_ax25_dev(dev)) != NULL)
			bpq_free_device(dev);
		break;
	default:
		break;
	}

	return NOTIFY_DONE;
}


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

/*
 * Initialize driver. To be called from af_ax25 if not compiled as a
 * module
 */
static int __init bpq_init_driver(void)
{
#ifdef CONFIG_PROC_FS
	if (!proc_create_seq("bpqether", 0444, init_net.proc_net, &bpq_seqops)) {
		printk(KERN_ERR
			"bpq: cannot create /proc/net/bpqether entry.\n");
		return -ENOENT;
	}
#endif  /* CONFIG_PROC_FS */

	dev_add_pack(&bpq_packet_type);

	register_netdevice_notifier(&bpq_dev_notifier);

	printk(banner);

	return 0;
}

static void __exit bpq_cleanup_driver(void)
{
	struct bpqdev *bpq;

	dev_remove_pack(&bpq_packet_type);

	unregister_netdevice_notifier(&bpq_dev_notifier);

	remove_proc_entry("bpqether", init_net.proc_net);

	rtnl_lock();
	while (!list_empty(&bpq_devices)) {
		bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
		bpq_free_device(bpq->axdev);
	}
	rtnl_unlock();
}

MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
MODULE_LICENSE("GPL");
module_init(bpq_init_driver);
module_exit(bpq_cleanup_driver);
Commit	Line	Data
ee5d8f4d	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* G8BPQ compatible "AX.25 via ethernet" driver release 004
	4	*
	5	* This code REQUIRES 2.0.0 or higher/ NET3.029
	6	*
1da177e4 LT	7	* This is a "pseudo" network driver to allow AX.25 over Ethernet
	8	* using G8BPQ encapsulation. It has been extracted from the protocol
	9	* implementation because
	10	*
	11	* - things got unreadable within the protocol stack
	12	* - to cure the protocol stack from "feature-ism"
	13	* - a protocol implementation shouldn't need to know on
	14	* which hardware it is running
	15	* - user-level programs like the AX.25 utilities shouldn't
	16	* need to know about the hardware.
	17	* - IP over ethernet encapsulated AX.25 was impossible
	18	* - rxecho.c did not work
	19	* - to have room for extensions
	20	* - it just deserves to "live" as an own driver
	21	*
	22	* This driver can use any ethernet destination address, and can be
	23	* limited to accept frames from one dedicated ethernet card only.
	24	*
	25	* Note that the driver sets up the BPQ devices automagically on
	26	* startup or (if started before the "insmod" of an ethernet device)
	27	* on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
	28	* the ethernet device (in fact: as soon as another ethernet or bpq
	29	* device gets "ifconfig"ured).
	30	*
	31	* I have heard that several people are thinking of experiments
	32	* with highspeed packet radio using existing ethernet cards.
	33	* Well, this driver is prepared for this purpose, just add
	34	* your tx key control and a txdelay / tailtime algorithm,
	35	* probably some buffering, and /voila/...
	36	*
	37	* History
	38	* BPQ 001 Joerg(DL1BKE) Extracted BPQ code from AX.25
	39	* protocol stack and added my own
	40	* yet existing patches
	41	* BPQ 002 Joerg(DL1BKE) Scan network device list on
	42	* startup.
	43	* BPQ 003 Joerg(DL1BKE) Ethernet destination address
	44	* and accepted source address
	45	* can be configured by an ioctl()
	46	* call.
	47	* Fixed to match Linux networking
	48	* changes - 2.1.15.
	49	* BPQ 004 Joerg(DL1BKE) Fixed to not lock up on ifconfig.
	50	*/
	51
1da177e4 LT	52	#include <linux/errno.h>
	53	#include <linux/types.h>
	54	#include <linux/socket.h>
	55	#include <linux/in.h>
	56	#include <linux/kernel.h>
	57	#include <linux/string.h>
	58	#include <linux/net.h>
5a0e3ad6	59	#include <linux/slab.h>
1da177e4 LT	60	#include <net/ax25.h>
	61	#include <linux/inet.h>
	62	#include <linux/netdevice.h>
0795af57	63	#include <linux/etherdevice.h>
1da177e4 LT	64	#include <linux/if_arp.h>
	65	#include <linux/skbuff.h>
	66	#include <net/sock.h>
7c0f6ba6	67	#include <linux/uaccess.h>
1da177e4 LT	68	#include <linux/mm.h>
	69	#include <linux/interrupt.h>
	70	#include <linux/notifier.h>
	71	#include <linux/proc_fs.h>
	72	#include <linux/seq_file.h>
	73	#include <linux/stat.h>
1da177e4 LT	74	#include <linux/module.h>
	75	#include <linux/init.h>
	76	#include <linux/rtnetlink.h>
	77
	78	#include <net/ip.h>
	79	#include <net/arp.h>
457c4cbc	80	#include <net/net_namespace.h>
1da177e4 LT	81
	82	#include <linux/bpqether.h>
	83
afa8c78b	84	static const char banner[] __initconst = KERN_INFO \
eb33ae24	85	"AX.25: bpqether driver version 004\n";
1da177e4	86
f2ccd8fa	87	static int bpq_rcv(struct sk_buff , struct net_device , struct packet_type , struct net_device );
1da177e4	88	static int bpq_device_event(struct notifier_block , unsigned long, void );
1da177e4	89
7546dd97	90	static struct packet_type bpq_packet_type __read_mostly = {
09640e63	91	.type = cpu_to_be16(ETH_P_BPQ),
1da177e4 LT	92	.func = bpq_rcv,
	93	};
	94
	95	static struct notifier_block bpq_dev_notifier = {
351638e7	96	.notifier_call = bpq_device_event,
1da177e4 LT	97	};
	98
	99
	100	struct bpqdev {
	101	struct list_head bpq_list; /* list of bpq devices chain */
	102	struct net_device ethdev; / link to ethernet device */
	103	struct net_device axdev; / bpq device (bpq#) */
1da177e4 LT	104	char dest_addr[6]; /* ether destination address */
	105	char acpt_addr[6]; /* accept ether frames from this address only */
	106	};
	107
	108	static LIST_HEAD(bpq_devices);
	109
1da177e4 LT	110	/* ------------------------------------------------------------------------ */
	111
	112
	113	/*
	114	* Get the ethernet device for a BPQ device
	115	*/
	116	static inline struct net_device bpq_get_ether_dev(struct net_device dev)
	117	{
	118	struct bpqdev *bpq = netdev_priv(dev);
	119
	120	return bpq ? bpq->ethdev : NULL;
	121	}
	122
	123	/*
	124	* Get the BPQ device for the ethernet device
	125	*/
	126	static inline struct net_device bpq_get_ax25_dev(struct net_device dev)
	127	{
	128	struct bpqdev *bpq;
	129
95f59bf8 MB	130	list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list,
95f59bf8 MB	131	lockdep_rtnl_is_held()) {
1da177e4 LT	132	if (bpq->ethdev == dev)
	133	return bpq->axdev;
	134	}
	135	return NULL;
	136	}
	137
	138	static inline int dev_is_ethdev(struct net_device *dev)
	139	{
807540ba	140	return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
1da177e4 LT	141	}
	142
	143	/* ------------------------------------------------------------------------ */
	144
	145
	146	/*
	147	* Receive an AX.25 frame via an ethernet interface.
	148	*/
f2ccd8fa	149	static int bpq_rcv(struct sk_buff skb, struct net_device dev, struct packet_type ptype, struct net_device orig_dev)
1da177e4 LT	150	{
	151	int len;
	152	char * ptr;
	153	struct ethhdr *eth;
	154	struct bpqdev *bpq;
	155
09ad9bc7	156	if (!net_eq(dev_net(dev), &init_net))
e730c155 EB	157	goto drop;
e730c155 EB	158
1da177e4 LT	159	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
	160	return NET_RX_DROP;
	161
	162	if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
	163	goto drop;
	164
	165	rcu_read_lock();
	166	dev = bpq_get_ax25_dev(dev);
	167
	168	if (dev == NULL \|\| !netif_running(dev))
	169	goto drop_unlock;
	170
	171	/*
	172	* if we want to accept frames from just one ethernet device
	173	* we check the source address of the sender.
	174	*/
	175
	176	bpq = netdev_priv(dev);
	177
	178	eth = eth_hdr(skb);
	179
	180	if (!(bpq->acpt_addr[0] & 0x01) &&
dc050c9e	181	!ether_addr_equal(eth->h_source, bpq->acpt_addr))
1da177e4 LT	182	goto drop_unlock;
	183
	184	if (skb_cow(skb, sizeof(struct ethhdr)))
	185	goto drop_unlock;
	186
	187	len = skb->data[0] + skb->data[1] * 256 - 5;
	188
	189	skb_pull(skb, 2); /* Remove the length bytes */
	190	skb_trim(skb, len); /* Set the length of the data */
	191
f57505fd SH	192	dev->stats.rx_packets++;
f57505fd SH	193	dev->stats.rx_bytes += len;
1da177e4 LT	194
	195	ptr = skb_push(skb, 1);
	196	*ptr = 0;
	197
56cb5156	198	skb->protocol = ax25_type_trans(skb, dev);
1da177e4	199	netif_rx(skb);
1da177e4 LT	200	unlock:
	201
	202	rcu_read_unlock();
	203
	204	return 0;
	205	drop_unlock:
	206	kfree_skb(skb);
	207	goto unlock;
	208
	209	drop:
	210	kfree_skb(skb);
	211	return 0;
	212	}
	213
	214	/*
	215	* Send an AX.25 frame via an ethernet interface
	216	*/
36e4d64a	217	static netdev_tx_t bpq_xmit(struct sk_buff skb, struct net_device dev)
1da177e4	218	{
1da177e4 LT	219	unsigned char *ptr;
1da177e4 LT	220	struct bpqdev *bpq;
f65d1f08	221	struct net_device *orig_dev;
1da177e4 LT	222	int size;
1da177e4 LT	223
1d5da757 EB	224	if (skb->protocol == htons(ETH_P_IP))
	225	return ax25_ip_xmit(skb);
	226
1da177e4 LT	227	/*
	228	* Just to be really sure not to send anything if the interface
	229	* is down, the ethernet device may have gone.
	230	*/
	231	if (!netif_running(dev)) {
	232	kfree_skb(skb);
d77eeb70	233	return NETDEV_TX_OK;
1da177e4 LT	234	}
1da177e4 LT	235
3eb00275	236	skb_pull(skb, 1); /* Drop KISS byte */
1da177e4 LT	237	size = skb->len;
	238
	239	/*
3eb00275 RB	240	* We're about to mess with the skb which may still shared with the
	241	* generic networking code so unshare and ensure it's got enough
	242	* space for the BPQ headers.
1da177e4	243	*/
3eb00275 RB	244	if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
	245	if (net_ratelimit())
	246	pr_err("bpqether: out of memory\n");
1da177e4	247	kfree_skb(skb);
3eb00275 RB	248
3eb00275 RB	249	return NETDEV_TX_OK;
1da177e4 LT	250	}
1da177e4 LT	251
3eb00275	252	ptr = skb_push(skb, 2); /* Make space for length */
1da177e4 LT	253
	254	*ptr++ = (size + 5) % 256;
	255	*ptr++ = (size + 5) / 256;
	256
	257	bpq = netdev_priv(dev);
	258
f65d1f08	259	orig_dev = dev;
1da177e4	260	if ((dev = bpq_get_ether_dev(dev)) == NULL) {
f65d1f08	261	orig_dev->stats.tx_dropped++;
1da177e4	262	kfree_skb(skb);
98ca4a46	263	return NETDEV_TX_OK;
1da177e4 LT	264	}
1da177e4 LT	265
56cb5156	266	skb->protocol = ax25_type_trans(skb, dev);
c1d2bbe1	267	skb_reset_network_header(skb);
0c4e8581	268	dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
f57505fd SH	269	dev->stats.tx_packets++;
f57505fd SH	270	dev->stats.tx_bytes+=skb->len;
1da177e4 LT	271
	272	dev_queue_xmit(skb);
	273	netif_wake_queue(dev);
6ed10654	274	return NETDEV_TX_OK;
1da177e4 LT	275	}
1da177e4 LT	276
1da177e4 LT	277	/*
	278	* Set AX.25 callsign
	279	*/
	280	static int bpq_set_mac_address(struct net_device dev, void addr)
	281	{
	282	struct sockaddr sa = (struct sockaddr )addr;
	283
	284	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
	285
	286	return 0;
	287	}
	288
	289	/* Ioctl commands
	290	*
	291	* SIOCSBPQETHOPT reserved for enhancements
	292	* SIOCSBPQETHADDR set the destination and accepted
	293	* source ethernet address (broadcast
	294	* or multicast: accept all)
	295	*/
	296	static int bpq_ioctl(struct net_device dev, struct ifreq ifr, int cmd)
	297	{
	298	struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
	299	struct bpqdev *bpq = netdev_priv(dev);
	300	struct bpq_req req;
	301
	302	if (!capable(CAP_NET_ADMIN))
	303	return -EPERM;
	304
	305	switch (cmd) {
	306	case SIOCSBPQETHOPT:
	307	if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
	308	return -EFAULT;
	309	switch (req.cmd) {
	310	case SIOCGBPQETHPARAM:
	311	case SIOCSBPQETHPARAM:
	312	default:
	313	return -EINVAL;
	314	}
	315
	316	break;
	317
	318	case SIOCSBPQETHADDR:
	319	if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
	320	return -EFAULT;
	321	if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
	322	return -EFAULT;
	323	break;
	324
	325	default:
	326	return -EINVAL;
	327	}
	328
	329	return 0;
	330	}
	331
	332	/*
	333	* open/close a device
	334	*/
	335	static int bpq_open(struct net_device *dev)
	336	{
	337	netif_start_queue(dev);
	338	return 0;
	339	}
	340
341	static int bpq_close(struct net_device *dev)
342	{
343	netif_stop_queue(dev);
344	return 0;
345	}
346
347
348	/* ------------------------------------------------------------------------ */
349
350
351	/*
352	* Proc filesystem
353	*/
1da177e4	354	static void bpq_seq_start(struct seq_file seq, loff_t *pos)
e334f564	355	__acquires(RCU)
1da177e4 LT	356	{
	357	int i = 1;
	358	struct bpqdev *bpqdev;
	359
	360	rcu_read_lock();
	361
	362	if (*pos == 0)
	363	return SEQ_START_TOKEN;
	364
bc0a7438	365	list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
1da177e4 LT	366	if (i == *pos)
	367	return bpqdev;
	368	}
	369	return NULL;
	370	}
	371
	372	static void bpq_seq_next(struct seq_file seq, void v, loff_t pos)
	373	{
	374	struct list_head *p;
13707f9e	375	struct bpqdev *bpqdev = v;
1da177e4 LT	376
	377	++*pos;
	378
	379	if (v == SEQ_START_TOKEN)
13707f9e	380	p = rcu_dereference(list_next_rcu(&bpq_devices));
1da177e4	381	else
13707f9e	382	p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list));
1da177e4 LT	383
1da177e4 LT	384	return (p == &bpq_devices) ? NULL
b34bd06e	385	: list_entry(p, struct bpqdev, bpq_list);
1da177e4 LT	386	}
	387
	388	static void bpq_seq_stop(struct seq_file seq, void v)
e334f564	389	__releases(RCU)
1da177e4 LT	390	{
	391	rcu_read_unlock();
	392	}
	393
	394
	395	static int bpq_seq_show(struct seq_file seq, void v)
	396	{
	397	if (v == SEQ_START_TOKEN)
	398	seq_puts(seq,
	399	"dev ether destination accept from\n");
	400	else {
	401	const struct bpqdev *bpqdev = v;
	402
e174961c	403	seq_printf(seq, "%-5s %-10s %pM ",
1da177e4	404	bpqdev->axdev->name, bpqdev->ethdev->name,
e174961c	405	bpqdev->dest_addr);
1da177e4	406
0795af57 JP	407	if (is_multicast_ether_addr(bpqdev->acpt_addr))
	408	seq_printf(seq, "*\n");
	409	else
e174961c	410	seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
1da177e4 LT	411
	412	}
	413	return 0;
	414	}
	415
4101dec9	416	static const struct seq_operations bpq_seqops = {
1da177e4 LT	417	.start = bpq_seq_start,
	418	.next = bpq_seq_next,
	419	.stop = bpq_seq_stop,
	420	.show = bpq_seq_show,
	421	};
	422
1da177e4 LT	423	/* ------------------------------------------------------------------------ */
1da177e4 LT	424
283767e7 SH	425	static const struct net_device_ops bpq_netdev_ops = {
	426	.ndo_open = bpq_open,
	427	.ndo_stop = bpq_close,
	428	.ndo_start_xmit = bpq_xmit,
	429	.ndo_set_mac_address = bpq_set_mac_address,
	430	.ndo_do_ioctl = bpq_ioctl,
	431	};
1da177e4 LT	432
	433	static void bpq_setup(struct net_device *dev)
	434	{
283767e7	435	dev->netdev_ops = &bpq_netdev_ops;
cf124db5	436	dev->needs_free_netdev = true;
1da177e4	437
15b1c0e8 RB	438	memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
15b1c0e8 RB	439	memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
1da177e4 LT	440
1da177e4 LT	441	dev->flags = 0;
aa43c5ff	442	dev->features = NETIF_F_LLTX; /* Allow recursion */
1da177e4	443
5f94bebe	444	#if IS_ENABLED(CONFIG_AX25)
3b04ddde	445	dev->header_ops = &ax25_header_ops;
1da177e4 LT	446	#endif
	447
	448	dev->type = ARPHRD_AX25;
	449	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
	450	dev->mtu = AX25_DEF_PACLEN;
	451	dev->addr_len = AX25_ADDR_LEN;
	452
	453	}
	454
	455	/*
	456	* Setup a new device.
	457	*/
	458	static int bpq_new_device(struct net_device *edev)
	459	{
	460	int err;
	461	struct net_device *ndev;
	462	struct bpqdev *bpq;
	463
c835a677 TG	464	ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", NET_NAME_UNKNOWN,
c835a677 TG	465	bpq_setup);
1da177e4 LT	466	if (!ndev)
	467	return -ENOMEM;
	468
	469
	470	bpq = netdev_priv(ndev);
	471	dev_hold(edev);
	472	bpq->ethdev = edev;
	473	bpq->axdev = ndev;
	474
4e8439aa SA	475	eth_broadcast_addr(bpq->dest_addr);
4e8439aa SA	476	eth_broadcast_addr(bpq->acpt_addr);
1da177e4	477
1da177e4 LT	478	err = register_netdevice(ndev);
	479	if (err)
	480	goto error;
	481
	482	/* List protected by RTNL */
	483	list_add_rcu(&bpq->bpq_list, &bpq_devices);
	484	return 0;
	485
	486	error:
	487	dev_put(edev);
	488	free_netdev(ndev);
	489	return err;
	490
	491	}
	492
	493	static void bpq_free_device(struct net_device *ndev)
	494	{
	495	struct bpqdev *bpq = netdev_priv(ndev);
	496
	497	dev_put(bpq->ethdev);
	498	list_del_rcu(&bpq->bpq_list);
	499
	500	unregister_netdevice(ndev);
	501	}
	502
	503	/*
	504	* Handle device status changes.
	505	*/
351638e7 JP	506	static int bpq_device_event(struct notifier_block *this,
351638e7 JP	507	unsigned long event, void *ptr)
1da177e4	508	{
351638e7	509	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1da177e4	510
09ad9bc7	511	if (!net_eq(dev_net(dev), &init_net))
e9dc8653 EB	512	return NOTIFY_DONE;
e9dc8653 EB	513
1da177e4 LT	514	if (!dev_is_ethdev(dev))
	515	return NOTIFY_DONE;
	516
1da177e4 LT	517	switch (event) {
	518	case NETDEV_UP: /* new ethernet device -> new BPQ interface */
	519	if (bpq_get_ax25_dev(dev) == NULL)
	520	bpq_new_device(dev);
	521	break;
	522
	523	case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */
	524	if ((dev = bpq_get_ax25_dev(dev)) != NULL)
	525	dev_close(dev);
	526	break;
	527
	528	case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
	529	if ((dev = bpq_get_ax25_dev(dev)) != NULL)
	530	bpq_free_device(dev);
	531	break;
	532	default:
	533	break;
	534	}
1da177e4 LT	535
	536	return NOTIFY_DONE;
	537	}
	538
	539
	540	/* ------------------------------------------------------------------------ */
	541
	542	/*
	543	* Initialize driver. To be called from af_ax25 if not compiled as a
	544	* module
	545	*/
	546	static int __init bpq_init_driver(void)
	547	{
	548	#ifdef CONFIG_PROC_FS
fddda2b7	549	if (!proc_create_seq("bpqether", 0444, init_net.proc_net, &bpq_seqops)) {
1da177e4 LT	550	printk(KERN_ERR
	551	"bpq: cannot create /proc/net/bpqether entry.\n");
	552	return -ENOENT;
	553	}
	554	#endif /* CONFIG_PROC_FS */
	555
	556	dev_add_pack(&bpq_packet_type);
	557
	558	register_netdevice_notifier(&bpq_dev_notifier);
	559
	560	printk(banner);
	561
	562	return 0;
	563	}
	564
	565	static void __exit bpq_cleanup_driver(void)
	566	{
	567	struct bpqdev *bpq;
	568
	569	dev_remove_pack(&bpq_packet_type);
	570
	571	unregister_netdevice_notifier(&bpq_dev_notifier);
	572
ece31ffd	573	remove_proc_entry("bpqether", init_net.proc_net);
1da177e4 LT	574
	575	rtnl_lock();
	576	while (!list_empty(&bpq_devices)) {
	577	bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
	578	bpq_free_device(bpq->axdev);
	579	}
	580	rtnl_unlock();
	581	}
	582
	583	MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
	584	MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
	585	MODULE_LICENSE("GPL");
	586	module_init(bpq_init_driver);
	587	module_exit(bpq_cleanup_driver);