9ed36279f6
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
152 lines
3.6 KiB
C
152 lines
3.6 KiB
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 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) {
|
|
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");
|