Import of Linus's Linux 1.1.68

1 files changed, 109 insertions, 0 deletions

diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
new file mode 100644
index 000000000..c70629d73
--- /dev/null
+++ b/drivers/net/dummy.c
@@ -0,0 +1,109 @@
+/* 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 thats all]
+			Alan Cox, 30th May 1994
+*/
+
+/* To have statistics (just packets sent) define this */
+#undef DUMMY_STATS
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/interrupt.h>
+#include <linux/ptrace.h>
+#include <linux/ioport.h>
+#include <linux/in.h>
+#include <linux/malloc.h>
+#include <linux/string.h>
+#include <asm/system.h>
+#include <asm/bitops.h>
+#include <asm/io.h>
+#include <asm/dma.h>
+#include <linux/errno.h>
+
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+
+static int dummy_xmit(struct sk_buff *skb, struct device *dev);
+#ifdef DUMMY_STATS
+static struct enet_statistics *dummy_get_stats(struct device *dev);
+#endif
+
+int
+dummy_init(struct device *dev)
+{
+/* I commented this out as bootup is noisy enough anyway and this driver
+   seems pretty reliable 8) 8) 8) */
+/*	printk ( KERN_INFO "Dummy net driver (94/05/27 v1.0)\n" ); */
+
+	/* Initialize the device structure. */
+	dev->hard_start_xmit	= dummy_xmit;
+
+#if DUMMY_STATS
+	dev->priv = kmalloc(sizeof(struct enet_statistics), GFP_KERNEL);
+	memset(dev->priv, 0, sizeof(struct enet_statistics));
+	dev->get_stats		= dummy_get_stats;
+#endif
+
+	/* Fill in the fields of the device structure with ethernet-generic values. */
+	ether_setup(dev);
+
+	return 0;
+}
+
+static int
+dummy_xmit(struct sk_buff *skb, struct device *dev)
+{
+#if DUMMY_STATS
+	struct enet_statistics *stats;
+#endif
+
+	if (skb == NULL || dev == NULL)
+		return 0;
+
+	dev_kfree_skb(skb, FREE_WRITE);
+
+#if DUMMY_STATS
+	stats = (struct enet_statistics *)dev->priv;
+	stats->tx_packets++;
+#endif
+
+	return 0;
+}
+
+#if DUMMY_STATS
+static struct enet_statistics *
+dummy_get_stats(struct device *dev)
+{
+	struct enet_statistics *stats = (struct enet_statistics*) dev->priv;
+	return stats;
+}
+#endif