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");