[linux.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/config.h>
#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 struct net_device_stats *dummy_get_stats(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->get_stats = dummy_get_stats;
	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)
{
	struct net_device_stats *stats = netdev_priv(dev);

	stats->tx_packets++;
	stats->tx_bytes+=skb->len;

	dev_kfree_skb(skb);
	return 0;
}

static struct net_device_stats *dummy_get_stats(struct net_device *dev)
{
	return netdev_priv(dev);
}

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(sizeof(struct net_device_stats),
				 "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) { 
		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
	14
	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
	31	#include <linux/config.h>
	32	#include <linux/module.h>
	33	#include <linux/kernel.h>
	34	#include <linux/netdevice.h>
	35	#include <linux/etherdevice.h>
	36	#include <linux/init.h>
	37	#include <linux/moduleparam.h>
	38
	39	static int numdummies = 1;
	40
	41	static int dummy_xmit(struct sk_buff skb, struct net_device dev);
	42	static struct net_device_stats dummy_get_stats(struct net_device dev);
	43
	44	static int dummy_set_address(struct net_device dev, void p)
	45	{
	46	struct sockaddr *sa = p;
	47
	48	if (!is_valid_ether_addr(sa->sa_data))
	49	return -EADDRNOTAVAIL;
	50
	51	memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN);
	52	return 0;
	53	}
	54
	55	/* fake multicast ability */
	56	static void set_multicast_list(struct net_device *dev)
	57	{
	58	}
	59
	60	static void __init dummy_setup(struct net_device *dev)
	61	{
	62	/* Initialize the device structure. */
	63	dev->get_stats = dummy_get_stats;
	64	dev->hard_start_xmit = dummy_xmit;
65	dev->set_multicast_list = set_multicast_list;
66	dev->set_mac_address = dummy_set_address;
67
68	/* Fill in device structure with ethernet-generic values. */
69	ether_setup(dev);
70	dev->tx_queue_len = 0;
71	dev->change_mtu = NULL;
72	dev->flags \|= IFF_NOARP;
73	dev->flags &= ~IFF_MULTICAST;
74	SET_MODULE_OWNER(dev);
75	random_ether_addr(dev->dev_addr);
76	}
77
78	static int dummy_xmit(struct sk_buff skb, struct net_device dev)
79	{
80	struct net_device_stats *stats = netdev_priv(dev);
81
82	stats->tx_packets++;
83	stats->tx_bytes+=skb->len;
84
85	dev_kfree_skb(skb);
86	return 0;
87	}
88
89	static struct net_device_stats dummy_get_stats(struct net_device dev)
90	{
91	return netdev_priv(dev);
92	}
93
94	static struct net_device **dummies;
95
96	/* Number of dummy devices to be set up by this module. */
97	module_param(numdummies, int, 0);
98	MODULE_PARM_DESC(numdummies, "Number of dummy pseudo devices");
99
100	static int __init dummy_init_one(int index)
101	{
102	struct net_device *dev_dummy;
103	int err;
104
105	dev_dummy = alloc_netdev(sizeof(struct net_device_stats),
106	"dummy%d", dummy_setup);
107
108	if (!dev_dummy)
109	return -ENOMEM;
110
111	if ((err = register_netdev(dev_dummy))) {
112	free_netdev(dev_dummy);
113	dev_dummy = NULL;
114	} else {
115	dummies[index] = dev_dummy;
116	}
117
118	return err;
119	}
120
121	static void dummy_free_one(int index)
122	{
123	unregister_netdev(dummies[index]);
124	free_netdev(dummies[index]);
125	}
126
127	static int __init dummy_init_module(void)
128	{
129	int i, err = 0;
130	dummies = kmalloc(numdummies * sizeof(void *), GFP_KERNEL);
131	if (!dummies)
132	return -ENOMEM;
133	for (i = 0; i < numdummies && !err; i++)
134	err = dummy_init_one(i);
135	if (err) {
136	while (--i >= 0)
137	dummy_free_one(i);
138	}
139	return err;
140	}
141
142	static void __exit dummy_cleanup_module(void)
143	{
144	int i;
145	for (i = 0; i < numdummies; i++)
146	dummy_free_one(i);
147	kfree(dummies);
148	}
149
150	module_init(dummy_init_module);
151	module_exit(dummy_cleanup_module);
152	MODULE_LICENSE("GPL");