238 lines
6.3 KiB
C
238 lines
6.3 KiB
C
/*
|
|
* 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
|
|
* 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.
|
|
*/
|
|
|
|
#ifdef LOOPBACK_TSO
|
|
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)->gso_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);
|
|
}
|
|
#endif /* LOOPBACK_TSO */
|
|
|
|
/*
|
|
* 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
|
|
|
|
#ifdef LOOPBACK_TSO
|
|
if (skb_is_gso(skb)) {
|
|
BUG_ON(skb->protocol != htons(ETH_P_IP));
|
|
BUG_ON(skb->nh.iph->protocol != IPPROTO_TCP);
|
|
|
|
emulate_large_send_offload(skb);
|
|
return 0;
|
|
}
|
|
#endif
|
|
dev->last_rx = jiffies;
|
|
|
|
lb_stats = &per_cpu(loopback_stats, get_cpu());
|
|
lb_stats->rx_bytes += skb->len;
|
|
lb_stats->tx_bytes = lb_stats->rx_bytes;
|
|
lb_stats->rx_packets++;
|
|
lb_stats->tx_packets = lb_stats->rx_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_each_possible_cpu(i) {
|
|
struct net_device_stats *lb_stats;
|
|
|
|
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
|
|
#ifdef LOOPBACK_TSO
|
|
| NETIF_F_TSO
|
|
#endif
|
|
| NETIF_F_NO_CSUM | NETIF_F_HIGHDMA
|
|
| NETIF_F_LLTX,
|
|
.ethtool_ops = &loopback_ethtool_ops,
|
|
};
|
|
|
|
/* Setup and register 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);
|