From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- drivers/net/dummy.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 drivers/net/dummy.c (limited to 'drivers/net/dummy.c') diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c new file mode 100644 index 00000000000..dd8c15ac5c7 --- /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 +#include +#include +#include +#include +#include +#include + +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"); -- cgit v1.2.3