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linux/net/ethernet/eth.c

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/*
* 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.
*
* Ethernet-type device handling.
*
* Version: @(#)eth.c 1.0.7 05/25/93
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Mark Evans, <evansmp@uhura.aston.ac.uk>
* Florian La Roche, <rzsfl@rz.uni-sb.de>
* Alan Cox, <gw4pts@gw4pts.ampr.org>
*
* Fixes:
* Mr Linux : Arp problems
* Alan Cox : Generic queue tidyup (very tiny here)
* Alan Cox : eth_header ntohs should be htons
* Alan Cox : eth_rebuild_header missing an htons and
* minor other things.
* Tegge : Arp bug fixes.
* Florian : Removed many unnecessary functions, code cleanup
* and changes for new arp and skbuff.
* Alan Cox : Redid header building to reflect new format.
* Alan Cox : ARP only when compiled with CONFIG_INET
* Greg Page : 802.2 and SNAP stuff.
* Alan Cox : MAC layer pointers/new format.
* Paul Gortmaker : eth_copy_and_sum shouldn't csum padding.
* Alan Cox : Protect against forwarding explosions with
* older network drivers and IFF_ALLMULTI.
* Christer Weinigel : Better rebuild header message.
* Andrew Morton : 26Feb01: kill ether_setup() - use netdev_boot_setup().
*
* 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/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/ip.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/if_ether.h>
#include <net/dst.h>
#include <net/arp.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/ip.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/checksum.h>
__setup("ether=", netdev_boot_setup);
/*
* Create the Ethernet MAC header for an arbitrary protocol layer
*
* saddr=NULL means use device source address
* daddr=NULL means leave destination address (eg unresolved arp)
*/
int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
void *daddr, void *saddr, unsigned len)
{
struct ethhdr *eth = (struct ethhdr *)skb_push(skb,ETH_HLEN);
/*
* Set the protocol type. For a packet of type ETH_P_802_3 we put the length
* in here instead. It is up to the 802.2 layer to carry protocol information.
*/
if(type!=ETH_P_802_3)
eth->h_proto = htons(type);
else
eth->h_proto = htons(len);
/*
* Set the source hardware address.
*/
if(!saddr)
saddr = dev->dev_addr;
memcpy(eth->h_source,saddr,dev->addr_len);
if(daddr)
{
memcpy(eth->h_dest,daddr,dev->addr_len);
return ETH_HLEN;
}
/*
* Anyway, the loopback-device should never use this function...
*/
if (dev->flags & (IFF_LOOPBACK|IFF_NOARP))
{
memset(eth->h_dest, 0, dev->addr_len);
return ETH_HLEN;
}
return -ETH_HLEN;
}
/*
* Rebuild the Ethernet MAC header. This is called after an ARP
* (or in future other address resolution) has completed on this
* sk_buff. We now let ARP fill in the other fields.
*
* This routine CANNOT use cached dst->neigh!
* Really, it is used only when dst->neigh is wrong.
*/
int eth_rebuild_header(struct sk_buff *skb)
{
struct ethhdr *eth = (struct ethhdr *)skb->data;
struct net_device *dev = skb->dev;
switch (eth->h_proto)
{
#ifdef CONFIG_INET
case __constant_htons(ETH_P_IP):
return arp_find(eth->h_dest, skb);
#endif
default:
printk(KERN_DEBUG
"%s: unable to resolve type %X addresses.\n",
dev->name, (int)eth->h_proto);
memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
break;
}
return 0;
}
/*
* Determine the packet's protocol ID. The rule here is that we
* assume 802.3 if the type field is short enough to be a length.
* This is normal practice and works for any 'now in use' protocol.
*/
__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
{
struct ethhdr *eth;
unsigned char *rawp;
skb->mac.raw = skb->data;
skb_pull(skb,ETH_HLEN);
eth = eth_hdr(skb);
if (is_multicast_ether_addr(eth->h_dest)) {
if (!compare_ether_addr(eth->h_dest, dev->broadcast))
skb->pkt_type = PACKET_BROADCAST;
else
skb->pkt_type = PACKET_MULTICAST;
}
/*
* This ALLMULTI check should be redundant by 1.4
* so don't forget to remove it.
*
* Seems, you forgot to remove it. All silly devices
* seems to set IFF_PROMISC.
*/
else if(1 /*dev->flags&IFF_PROMISC*/) {
if (unlikely(compare_ether_addr(eth->h_dest, dev->dev_addr)))
skb->pkt_type = PACKET_OTHERHOST;
}
if (ntohs(eth->h_proto) >= 1536)
return eth->h_proto;
rawp = skb->data;
/*
* This is a magic hack to spot IPX packets. Older Novell breaks
* the protocol design and runs IPX over 802.3 without an 802.2 LLC
* layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
* won't work for fault tolerant netware but does for the rest.
*/
if (*(unsigned short *)rawp == 0xFFFF)
return htons(ETH_P_802_3);
/*
* Real 802.2 LLC
*/
return htons(ETH_P_802_2);
}
static int eth_header_parse(struct sk_buff *skb, unsigned char *haddr)
{
struct ethhdr *eth = eth_hdr(skb);
memcpy(haddr, eth->h_source, ETH_ALEN);
return ETH_ALEN;
}
int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh)
{
unsigned short type = hh->hh_type;
struct ethhdr *eth;
struct net_device *dev = neigh->dev;
eth = (struct ethhdr*)
(((u8*)hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
if (type == __constant_htons(ETH_P_802_3))
return -1;
eth->h_proto = type;
memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
memcpy(eth->h_dest, neigh->ha, dev->addr_len);
hh->hh_len = ETH_HLEN;
return 0;
}
/*
* Called by Address Resolution module to notify changes in address.
*/
void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev, unsigned char * haddr)
{
memcpy(((u8*)hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
haddr, dev->addr_len);
}
EXPORT_SYMBOL(eth_type_trans);
static int eth_mac_addr(struct net_device *dev, void *p)
{
struct sockaddr *addr=p;
if (netif_running(dev))
return -EBUSY;
memcpy(dev->dev_addr, addr->sa_data,dev->addr_len);
return 0;
}
static int eth_change_mtu(struct net_device *dev, int new_mtu)
{
if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
return -EINVAL;
dev->mtu = new_mtu;
return 0;
}
/*
* Fill in the fields of the device structure with ethernet-generic values.
*/
void ether_setup(struct net_device *dev)
{
dev->change_mtu = eth_change_mtu;
dev->hard_header = eth_header;
dev->rebuild_header = eth_rebuild_header;
dev->set_mac_address = eth_mac_addr;
dev->hard_header_cache = eth_header_cache;
dev->header_cache_update= eth_header_cache_update;
dev->hard_header_parse = eth_header_parse;
dev->type = ARPHRD_ETHER;
dev->hard_header_len = ETH_HLEN;
dev->mtu = ETH_DATA_LEN;
dev->addr_len = ETH_ALEN;
dev->tx_queue_len = 1000; /* Ethernet wants good queues */
dev->flags = IFF_BROADCAST|IFF_MULTICAST;
memset(dev->broadcast,0xFF, ETH_ALEN);
}
EXPORT_SYMBOL(ether_setup);
/**
* alloc_etherdev - Allocates and sets up an ethernet device
* @sizeof_priv: Size of additional driver-private structure to be allocated
* for this ethernet device
*
* Fill in the fields of the device structure with ethernet-generic
* values. Basically does everything except registering the device.
*
* Constructs a new net device, complete with a private data area of
* size @sizeof_priv. A 32-byte (not bit) alignment is enforced for
* this private data area.
*/
struct net_device *alloc_etherdev(int sizeof_priv)
{
return alloc_netdev(sizeof_priv, "eth%d", ether_setup);
}
EXPORT_SYMBOL(alloc_etherdev);
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