1 files changed, 152 insertions, 0 deletions
diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
new file mode 100644
index 000000000000..dd8c15ac5c77
--- /dev/null
+++ b/drivers/net/dummy.c
@@ -0,0 +1,152 @@
+/* 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");