/* dummy.c: a dummy net driver
|
/* dummy.c: a dummy net driver
|
|
|
The purpose of this driver is to provide a device to point a
|
The purpose of this driver is to provide a device to point a
|
route through, but not to actually transmit packets.
|
route through, but not to actually transmit packets.
|
|
|
Why? If you have a machine whose only connection is an occasional
|
Why? If you have a machine whose only connection is an occasional
|
PPP/SLIP/PLIP link, you can only connect to your own hostname
|
PPP/SLIP/PLIP link, you can only connect to your own hostname
|
when the link is up. Otherwise you have to use localhost.
|
when the link is up. Otherwise you have to use localhost.
|
This isn't very consistent.
|
This isn't very consistent.
|
|
|
One solution is to set up a dummy link using PPP/SLIP/PLIP,
|
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.
|
but this seems (to me) too much overhead for too little gain.
|
This driver provides a small alternative. Thus you can do
|
This driver provides a small alternative. Thus you can do
|
|
|
[when not running slip]
|
[when not running slip]
|
ifconfig dummy slip.addr.ess.here up
|
ifconfig dummy slip.addr.ess.here up
|
[to go to slip]
|
[to go to slip]
|
ifconfig dummy down
|
ifconfig dummy down
|
dip whatever
|
dip whatever
|
|
|
This was written by looking at Donald Becker's skeleton driver
|
This was written by looking at Donald Becker's skeleton driver
|
and the loopback driver. I then threw away anything that didn't
|
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
|
apply! Thanks to Alan Cox for the key clue on what to do with
|
misguided packets.
|
misguided packets.
|
|
|
Nick Holloway, 27th May 1994
|
Nick Holloway, 27th May 1994
|
[I tweaked this explanation a little but that's all]
|
[I tweaked this explanation a little but that's all]
|
Alan Cox, 30th May 1994
|
Alan Cox, 30th May 1994
|
*/
|
*/
|
|
|
/* To have statistics (just packets sent) define this */
|
/* To have statistics (just packets sent) define this */
|
#undef DUMMY_STATS
|
#undef DUMMY_STATS
|
|
|
#include <linux/module.h>
|
#include <linux/module.h>
|
|
|
#include <linux/kernel.h>
|
#include <linux/kernel.h>
|
#include <linux/sched.h>
|
#include <linux/sched.h>
|
#include <linux/types.h>
|
#include <linux/types.h>
|
#include <linux/fcntl.h>
|
#include <linux/fcntl.h>
|
#include <linux/interrupt.h>
|
#include <linux/interrupt.h>
|
#include <linux/ptrace.h>
|
#include <linux/ptrace.h>
|
#include <linux/ioport.h>
|
#include <linux/ioport.h>
|
#include <linux/in.h>
|
#include <linux/in.h>
|
#include <linux/malloc.h>
|
#include <linux/malloc.h>
|
#include <linux/string.h>
|
#include <linux/string.h>
|
#include <asm/system.h>
|
#include <asm/system.h>
|
#include <asm/bitops.h>
|
#include <asm/bitops.h>
|
#include <asm/io.h>
|
#include <asm/io.h>
|
#include <asm/dma.h>
|
#include <asm/dma.h>
|
#include <linux/errno.h>
|
#include <linux/errno.h>
|
|
|
#include <linux/netdevice.h>
|
#include <linux/netdevice.h>
|
#include <linux/etherdevice.h>
|
#include <linux/etherdevice.h>
|
#include <linux/skbuff.h>
|
#include <linux/skbuff.h>
|
|
|
static int dummy_xmit(struct sk_buff *skb, struct device *dev);
|
static int dummy_xmit(struct sk_buff *skb, struct device *dev);
|
#ifdef DUMMY_STATS
|
#ifdef DUMMY_STATS
|
static struct enet_statistics *dummy_get_stats(struct device *dev);
|
static struct enet_statistics *dummy_get_stats(struct device *dev);
|
#endif
|
#endif
|
|
|
static int dummy_open(struct device *dev)
|
static int dummy_open(struct device *dev)
|
{
|
{
|
MOD_INC_USE_COUNT;
|
MOD_INC_USE_COUNT;
|
return 0;
|
return 0;
|
}
|
}
|
|
|
static int dummy_close(struct device *dev)
|
static int dummy_close(struct device *dev)
|
{
|
{
|
MOD_DEC_USE_COUNT;
|
MOD_DEC_USE_COUNT;
|
return 0;
|
return 0;
|
}
|
}
|
|
|
static int dummy_rebuild(void *eth, struct device *dev, unsigned long raddr, struct sk_buff *skb)
|
static int dummy_rebuild(void *eth, struct device *dev, unsigned long raddr, struct sk_buff *skb)
|
{
|
{
|
return 0;
|
return 0;
|
}
|
}
|
|
|
int dummy_init(struct device *dev)
|
int dummy_init(struct device *dev)
|
{
|
{
|
/* I commented this out as bootup is noisy enough anyway and this driver
|
/* I commented this out as bootup is noisy enough anyway and this driver
|
seems pretty reliable 8) 8) 8) */
|
seems pretty reliable 8) 8) 8) */
|
/* printk ( KERN_INFO "Dummy net driver (94/05/27 v1.0)\n" ); */
|
/* printk ( KERN_INFO "Dummy net driver (94/05/27 v1.0)\n" ); */
|
|
|
/* Initialize the device structure. */
|
/* Initialize the device structure. */
|
dev->hard_start_xmit = dummy_xmit;
|
dev->hard_start_xmit = dummy_xmit;
|
|
|
#if DUMMY_STATS
|
#if DUMMY_STATS
|
dev->priv = kmalloc(sizeof(struct enet_statistics), GFP_KERNEL);
|
dev->priv = kmalloc(sizeof(struct enet_statistics), GFP_KERNEL);
|
if (dev->priv == NULL)
|
if (dev->priv == NULL)
|
return -ENOMEM;
|
return -ENOMEM;
|
memset(dev->priv, 0, sizeof(struct enet_statistics));
|
memset(dev->priv, 0, sizeof(struct enet_statistics));
|
dev->get_stats = dummy_get_stats;
|
dev->get_stats = dummy_get_stats;
|
#endif
|
#endif
|
|
|
dev->open = dummy_open;
|
dev->open = dummy_open;
|
dev->stop = dummy_close;
|
dev->stop = dummy_close;
|
|
|
/* Fill in the fields of the device structure with ethernet-generic values. */
|
/* Fill in the fields of the device structure with ethernet-generic values. */
|
ether_setup(dev);
|
ether_setup(dev);
|
dev->flags |= IFF_NOARP;
|
dev->flags |= IFF_NOARP;
|
dev->rebuild_header = dummy_rebuild;
|
dev->rebuild_header = dummy_rebuild;
|
|
|
return 0;
|
return 0;
|
}
|
}
|
|
|
static int
|
static int
|
dummy_xmit(struct sk_buff *skb, struct device *dev)
|
dummy_xmit(struct sk_buff *skb, struct device *dev)
|
{
|
{
|
#if DUMMY_STATS
|
#if DUMMY_STATS
|
struct enet_statistics *stats;
|
struct enet_statistics *stats;
|
#endif
|
#endif
|
|
|
if (skb == NULL || dev == NULL)
|
if (skb == NULL || dev == NULL)
|
return 0;
|
return 0;
|
|
|
dev_kfree_skb(skb, FREE_WRITE);
|
dev_kfree_skb(skb, FREE_WRITE);
|
|
|
#if DUMMY_STATS
|
#if DUMMY_STATS
|
stats = (struct enet_statistics *)dev->priv;
|
stats = (struct enet_statistics *)dev->priv;
|
stats->tx_packets++;
|
stats->tx_packets++;
|
#endif
|
#endif
|
|
|
return 0;
|
return 0;
|
}
|
}
|
|
|
#if DUMMY_STATS
|
#if DUMMY_STATS
|
static struct enet_statistics *
|
static struct enet_statistics *
|
dummy_get_stats(struct device *dev)
|
dummy_get_stats(struct device *dev)
|
{
|
{
|
struct enet_statistics *stats = (struct enet_statistics*) dev->priv;
|
struct enet_statistics *stats = (struct enet_statistics*) dev->priv;
|
return stats;
|
return stats;
|
}
|
}
|
#endif
|
#endif
|
|
|
#ifdef MODULE
|
#ifdef MODULE
|
|
|
static int dummy_probe(struct device *dev)
|
static int dummy_probe(struct device *dev)
|
{
|
{
|
dummy_init(dev);
|
dummy_init(dev);
|
return 0;
|
return 0;
|
}
|
}
|
|
|
static struct device dev_dummy = {
|
static struct device dev_dummy = {
|
"dummy0\0 ",
|
"dummy0\0 ",
|
0, 0, 0, 0,
|
0, 0, 0, 0,
|
0x0, 0,
|
0x0, 0,
|
0, 0, 0, NULL, dummy_probe };
|
0, 0, 0, NULL, dummy_probe };
|
|
|
int init_module(void)
|
int init_module(void)
|
{
|
{
|
/* Find a name for this unit */
|
/* Find a name for this unit */
|
int ct= 1;
|
int ct= 1;
|
|
|
while(dev_get(dev_dummy.name)!=NULL && ct<100)
|
while(dev_get(dev_dummy.name)!=NULL && ct<100)
|
{
|
{
|
sprintf(dev_dummy.name,"dummy%d",ct);
|
sprintf(dev_dummy.name,"dummy%d",ct);
|
ct++;
|
ct++;
|
}
|
}
|
if(ct==100)
|
if(ct==100)
|
return -ENFILE;
|
return -ENFILE;
|
|
|
if (register_netdev(&dev_dummy) != 0)
|
if (register_netdev(&dev_dummy) != 0)
|
return -EIO;
|
return -EIO;
|
return 0;
|
return 0;
|
}
|
}
|
|
|
void cleanup_module(void)
|
void cleanup_module(void)
|
{
|
{
|
unregister_netdev(&dev_dummy);
|
unregister_netdev(&dev_dummy);
|
kfree(dev_dummy.priv);
|
kfree(dev_dummy.priv);
|
dev_dummy.priv = NULL;
|
dev_dummy.priv = NULL;
|
}
|
}
|
#endif /* MODULE */
|
#endif /* MODULE */
|
|
|
