[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / net / dummy.c

/* dummy.c: a dummy net driver

	The purpose of this driver is to provide a device to point a
	route through, but not to actually transmit packets.

	Why?  If you have a machine whose only connection is an occasional
	PPP/SLIP/PLIP link, you can only connect to your own hostname
	when the link is up.  Otherwise you have to use localhost.
	This isn't very consistent.

	One solution is to set up a dummy link using PPP/SLIP/PLIP,
	but this seems (to me) too much overhead for too little gain.
	This driver provides a small alternative. Thus you can do

	[when not running slip]
		ifconfig dummy slip.addr.ess.here up
	[to go to slip]
		ifconfig dummy down
		dip whatever

	This was written by looking at Donald Becker's skeleton driver
	and the loopback driver.  I then threw away anything that didn't
	apply!	Thanks to Alan Cox for the key clue on what to do with
	misguided packets.

			Nick Holloway, 27th May 1994
	[I tweaked this explanation a little but that's all]
			Alan Cox, 30th May 1994
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/moduleparam.h>

static int numdummies = 1;

static int dummy_xmit(struct sk_buff *skb, struct net_device *dev);

static int dummy_set_address(struct net_device *dev, void *p)
{
	struct sockaddr *sa = p;

	if (!is_valid_ether_addr(sa->sa_data))
		return -EADDRNOTAVAIL;

	memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN);
	return 0;
}

/* fake multicast ability */
static void set_multicast_list(struct net_device *dev)
{
}

static void __init dummy_setup(struct net_device *dev)
{
	/* Initialize the device structure. */
	dev->hard_start_xmit = dummy_xmit;
	dev->set_multicast_list = set_multicast_list;
	dev->set_mac_address = dummy_set_address;

	/* Fill in device structure with ethernet-generic values. */
	ether_setup(dev);
	dev->tx_queue_len = 0;
	dev->change_mtu = NULL;
	dev->flags |= IFF_NOARP;
	dev->flags &= ~IFF_MULTICAST;
	SET_MODULE_OWNER(dev);
	random_ether_addr(dev->dev_addr);
}

static int dummy_xmit(struct sk_buff *skb, struct net_device *dev)
{
	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;

	dev_kfree_skb(skb);
	return 0;
}

static struct net_device **dummies;

/* Number of dummy devices to be set up by this module. */
module_param(numdummies, int, 0);
MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices");

static int __init dummy_init_one(int index)
{
	struct net_device *dev_dummy;
	int err;

	dev_dummy = alloc_netdev(0, "dummy%d", dummy_setup);

	if (!dev_dummy)
		return -ENOMEM;

	if ((err = register_netdev(dev_dummy))) {
		free_netdev(dev_dummy);
		dev_dummy = NULL;
	} else {
		dummies[index] = dev_dummy;
	}

	return err;
}

static void dummy_free_one(int index)
{
	unregister_netdev(dummies[index]);
	free_netdev(dummies[index]);
}

static int __init dummy_init_module(void)
{
	int i, err = 0;
	dummies = kmalloc(numdummies * sizeof(void *), GFP_KERNEL);
	if (!dummies)
		return -ENOMEM;
	for (i = 0; i < numdummies && !err; i++)
		err = dummy_init_one(i);
	if (err) {
		i--;
		while (--i >= 0)
			dummy_free_one(i);
	}
	return err;
}

static void __exit dummy_cleanup_module(void)
{
	int i;
	for (i = 0; i < numdummies; i++)
		dummy_free_one(i);
	kfree(dummies);
}

module_init(dummy_init_module);
module_exit(dummy_cleanup_module);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/* dummy.c: a dummy net driver
	2
	3	The purpose of this driver is to provide a device to point a
	4	route through, but not to actually transmit packets.
	5
	6	Why? If you have a machine whose only connection is an occasional
	7	PPP/SLIP/PLIP link, you can only connect to your own hostname
	8	when the link is up. Otherwise you have to use localhost.
	9	This isn't very consistent.
	10
	11	One solution is to set up a dummy link using PPP/SLIP/PLIP,
	12	but this seems (to me) too much overhead for too little gain.
	13	This driver provides a small alternative. Thus you can do
6aa20a22	14
1da177e4 LT	15	[when not running slip]
	16	ifconfig dummy slip.addr.ess.here up
	17	[to go to slip]
	18	ifconfig dummy down
	19	dip whatever
	20
	21	This was written by looking at Donald Becker's skeleton driver
	22	and the loopback driver. I then threw away anything that didn't
	23	apply! Thanks to Alan Cox for the key clue on what to do with
	24	misguided packets.
	25
	26	Nick Holloway, 27th May 1994
	27	[I tweaked this explanation a little but that's all]
	28	Alan Cox, 30th May 1994
	29	*/
	30
1da177e4 LT	31	#include <linux/module.h>
	32	#include <linux/kernel.h>
	33	#include <linux/netdevice.h>
	34	#include <linux/etherdevice.h>
	35	#include <linux/init.h>
	36	#include <linux/moduleparam.h>
	37
	38	static int numdummies = 1;
	39
	40	static int dummy_xmit(struct sk_buff skb, struct net_device dev);
1da177e4 LT	41
	42	static int dummy_set_address(struct net_device dev, void p)
	43	{
	44	struct sockaddr *sa = p;
	45
6aa20a22	46	if (!is_valid_ether_addr(sa->sa_data))
1da177e4	47	return -EADDRNOTAVAIL;
6aa20a22	48
1da177e4 LT	49	memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN);
	50	return 0;
	51	}
	52
	53	/* fake multicast ability */
	54	static void set_multicast_list(struct net_device *dev)
	55	{
	56	}
	57
	58	static void __init dummy_setup(struct net_device *dev)
	59	{
	60	/* Initialize the device structure. */
1da177e4 LT	61	dev->hard_start_xmit = dummy_xmit;
	62	dev->set_multicast_list = set_multicast_list;
	63	dev->set_mac_address = dummy_set_address;
	64
	65	/* Fill in device structure with ethernet-generic values. */
	66	ether_setup(dev);
	67	dev->tx_queue_len = 0;
	68	dev->change_mtu = NULL;
	69	dev->flags \|= IFF_NOARP;
	70	dev->flags &= ~IFF_MULTICAST;
	71	SET_MODULE_OWNER(dev);
	72	random_ether_addr(dev->dev_addr);
	73	}
	74
	75	static int dummy_xmit(struct sk_buff skb, struct net_device dev)
	76	{
58651b24 PM	77	dev->stats.tx_packets++;
58651b24 PM	78	dev->stats.tx_bytes += skb->len;
1da177e4 LT	79
	80	dev_kfree_skb(skb);
	81	return 0;
	82	}
	83
1da177e4 LT	84	static struct net_device **dummies;
	85
	86	/* Number of dummy devices to be set up by this module. */
	87	module_param(numdummies, int, 0);
	88	MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices");
	89
	90	static int __init dummy_init_one(int index)
	91	{
	92	struct net_device *dev_dummy;
	93	int err;
	94
58651b24	95	dev_dummy = alloc_netdev(0, "dummy%d", dummy_setup);
1da177e4 LT	96
	97	if (!dev_dummy)
	98	return -ENOMEM;
	99
	100	if ((err = register_netdev(dev_dummy))) {
	101	free_netdev(dev_dummy);
	102	dev_dummy = NULL;
	103	} else {
6aa20a22	104	dummies[index] = dev_dummy;
1da177e4 LT	105	}
	106
	107	return err;
	108	}
	109
	110	static void dummy_free_one(int index)
	111	{
	112	unregister_netdev(dummies[index]);
	113	free_netdev(dummies[index]);
6aa20a22	114	}
1da177e4 LT	115
1da177e4 LT	116	static int __init dummy_init_module(void)
6aa20a22	117	{
1da177e4	118	int i, err = 0;
6aa20a22	119	dummies = kmalloc(numdummies * sizeof(void *), GFP_KERNEL);
1da177e4	120	if (!dummies)
6aa20a22	121	return -ENOMEM;
1da177e4	122	for (i = 0; i < numdummies && !err; i++)
6aa20a22 JG	123	err = dummy_init_one(i);
6aa20a22 JG	124	if (err) {
9ed36279	125	i--;
1da177e4 LT	126	while (--i >= 0)
	127	dummy_free_one(i);
	128	}
	129	return err;
6aa20a22	130	}
1da177e4 LT	131
	132	static void __exit dummy_cleanup_module(void)
	133	{
	134	int i;
6aa20a22 JG	135	for (i = 0; i < numdummies; i++)
	136	dummy_free_one(i);
	137	kfree(dummies);
1da177e4 LT	138	}
	139
	140	module_init(dummy_init_module);
	141	module_exit(dummy_cleanup_module);
	142	MODULE_LICENSE("GPL");