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!

1 files changed, 233 insertions, 0 deletions

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
new file mode 100644
index 000000000000..2ffc31708d5f
--- /dev/null
+++ b/drivers/net/loopback.c
@@ -0,0 +1,233 @@
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Pseudo-driver for the loopback interface.
+ *
+ * Version:	@(#)loopback.c	1.0.4b	08/16/93
+ *
+ * Authors:	Ross Biro, <bir7@leland.Stanford.Edu>
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *		Donald Becker, <becker@scyld.com>
+ *
+ *		Alan Cox	:	Fixed oddments for NET3.014
+ *		Alan Cox	:	Rejig for NET3.029 snap #3
+ *		Alan Cox	: 	Fixed NET3.029 bugs and sped up
+ *		Larry McVoy	:	Tiny tweak to double performance
+ *		Alan Cox	:	Backed out LMV's tweak - the linux mm
+ *					can't take it...
+ *              Michael Griffith:       Don't bother computing the checksums
+ *                                      on packets received on the loopback
+ *                                      interface.
+ *		Alexey Kuznetsov:	Potential hang under some extreme
+ *					cases removed.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/socket.h>
+#include <linux/errno.h>
+#include <linux/fcntl.h>
+#include <linux/in.h>
+#include <linux/init.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/ethtool.h>
+#include <net/sock.h>
+#include <net/checksum.h>
+#include <linux/if_ether.h>	/* For the statistics structure. */
+#include <linux/if_arp.h>	/* For ARPHRD_ETHER */
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/percpu.h>
+
+static DEFINE_PER_CPU(struct net_device_stats, loopback_stats);
+
+#define LOOPBACK_OVERHEAD (128 + MAX_HEADER + 16 + 16)
+
+/* KISS: just allocate small chunks and copy bits.
+ *
+ * So, in fact, this is documentation, explaining what we expect
+ * of largesending device modulo TCP checksum, which is ignored for loopback.
+ */
+
+static void emulate_large_send_offload(struct sk_buff *skb)
+{
+	struct iphdr *iph = skb->nh.iph;
+	struct tcphdr *th = (struct tcphdr*)(skb->nh.raw + (iph->ihl * 4));
+	unsigned int doffset = (iph->ihl + th->doff) * 4;
+	unsigned int mtu = skb_shinfo(skb)->tso_size + doffset;
+	unsigned int offset = 0;
+	u32 seq = ntohl(th->seq);
+	u16 id  = ntohs(iph->id);
+
+	while (offset + doffset < skb->len) {
+		unsigned int frag_size = min(mtu, skb->len - offset) - doffset;
+		struct sk_buff *nskb = alloc_skb(mtu + 32, GFP_ATOMIC);
+
+		if (!nskb)
+			break;
+		skb_reserve(nskb, 32);
+		nskb->mac.raw = nskb->data - 14;
+		nskb->nh.raw = nskb->data;
+		iph = nskb->nh.iph;
+		memcpy(nskb->data, skb->nh.raw, doffset);
+		if (skb_copy_bits(skb,
+				  doffset + offset,
+				  nskb->data + doffset,
+				  frag_size))
+			BUG();
+		skb_put(nskb, doffset + frag_size);
+		nskb->ip_summed = CHECKSUM_UNNECESSARY;
+		nskb->dev = skb->dev;
+		nskb->priority = skb->priority;
+		nskb->protocol = skb->protocol;
+		nskb->dst = dst_clone(skb->dst);
+		memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
+		nskb->pkt_type = skb->pkt_type;
+
+		th = (struct tcphdr*)(nskb->nh.raw + iph->ihl*4);
+		iph->tot_len = htons(frag_size + doffset);
+		iph->id = htons(id);
+		iph->check = 0;
+		iph->check = ip_fast_csum((unsigned char *) iph, iph->ihl);
+		th->seq = htonl(seq);
+		if (offset + doffset + frag_size < skb->len)
+			th->fin = th->psh = 0;
+		netif_rx(nskb);
+		offset += frag_size;
+		seq += frag_size;
+		id++;
+	}
+
+	dev_kfree_skb(skb);
+}
+
+/*
+ * The higher levels take care of making this non-reentrant (it's
+ * called with bh's disabled).
+ */
+static int loopback_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct net_device_stats *lb_stats;
+
+	skb_orphan(skb);
+
+	skb->protocol=eth_type_trans(skb,dev);
+	skb->dev=dev;
+#ifndef LOOPBACK_MUST_CHECKSUM
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+#endif
+
+	if (skb_shinfo(skb)->tso_size) {
+		BUG_ON(skb->protocol != htons(ETH_P_IP));
+		BUG_ON(skb->nh.iph->protocol != IPPROTO_TCP);
+
+		emulate_large_send_offload(skb);
+		return 0;
+	}
+
+	dev->last_rx = jiffies;
+
+	lb_stats = &per_cpu(loopback_stats, get_cpu());
+	lb_stats->rx_bytes += skb->len;
+	lb_stats->tx_bytes += skb->len;
+	lb_stats->rx_packets++;
+	lb_stats->tx_packets++;
+	put_cpu();
+
+	netif_rx(skb);
+
+	return(0);
+}
+
+static struct net_device_stats *get_stats(struct net_device *dev)
+{
+	struct net_device_stats *stats = dev->priv;
+	int i;
+
+	if (!stats) {
+		return NULL;
+	}
+
+	memset(stats, 0, sizeof(struct net_device_stats));
+
+	for (i=0; i < NR_CPUS; i++) {
+		struct net_device_stats *lb_stats;
+
+		if (!cpu_possible(i)) 
+			continue;
+		lb_stats = &per_cpu(loopback_stats, i);
+		stats->rx_bytes   += lb_stats->rx_bytes;
+		stats->tx_bytes   += lb_stats->tx_bytes;
+		stats->rx_packets += lb_stats->rx_packets;
+		stats->tx_packets += lb_stats->tx_packets;
+	}
+				
+	return stats;
+}
+
+static u32 loopback_get_link(struct net_device *dev)
+{
+	return 1;
+}
+
+static struct ethtool_ops loopback_ethtool_ops = {
+	.get_link		= loopback_get_link,
+	.get_tso		= ethtool_op_get_tso,
+	.set_tso		= ethtool_op_set_tso,
+};
+
+struct net_device loopback_dev = {
+	.name	 		= "lo",
+	.mtu			= (16 * 1024) + 20 + 20 + 12,
+	.hard_start_xmit	= loopback_xmit,
+	.hard_header		= eth_header,
+	.hard_header_cache	= eth_header_cache,
+	.header_cache_update	= eth_header_cache_update,
+	.hard_header_len	= ETH_HLEN,	/* 14	*/
+	.addr_len		= ETH_ALEN,	/* 6	*/
+	.tx_queue_len		= 0,
+	.type			= ARPHRD_LOOPBACK,	/* 0x0001*/
+	.rebuild_header		= eth_rebuild_header,
+	.flags			= IFF_LOOPBACK,
+	.features 		= NETIF_F_SG|NETIF_F_FRAGLIST
+				  |NETIF_F_NO_CSUM|NETIF_F_HIGHDMA
+				  |NETIF_F_LLTX,
+	.ethtool_ops		= &loopback_ethtool_ops,
+};
+
+/* Setup and register the of the LOOPBACK device. */
+int __init loopback_init(void)
+{
+	struct net_device_stats *stats;
+
+	/* Can survive without statistics */
+	stats = kmalloc(sizeof(struct net_device_stats), GFP_KERNEL);
+	if (stats) {
+		memset(stats, 0, sizeof(struct net_device_stats));
+		loopback_dev.priv = stats;
+		loopback_dev.get_stats = &get_stats;
+	}
+	
+	return register_netdev(&loopback_dev);
+};
+
+EXPORT_SYMBOL(loopback_dev);