ip: sysctl documentation cleanup

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / ethernet / eth.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.
 *
 *              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/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>

__setup("ether=", netdev_boot_setup);

/**
 * eth_header - create the Ethernet header
 * @skb:        buffer to alter
 * @dev:        source device
 * @type:       Ethernet type field
 * @daddr: destination address (NULL leave destination address)
 * @saddr: source address (NULL use device source address)
 * @len:   packet length (<= skb->len)
 *
 *
 * 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.
 */
int eth_header(struct sk_buff *skb, struct net_device *dev,
               unsigned short type,
               const void *daddr, const void *saddr, unsigned len)
{
        struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);

        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, ETH_ALEN);

        if (daddr) {
                memcpy(eth->h_dest, daddr, ETH_ALEN);
                return ETH_HLEN;
        }

        /*
         *      Anyway, the loopback-device should never use this function...
         */

        if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
                memset(eth->h_dest, 0, ETH_ALEN);
                return ETH_HLEN;
        }

        return -ETH_HLEN;
}
EXPORT_SYMBOL(eth_header);

/**
 * eth_rebuild_header- rebuild the Ethernet MAC header.
 * @skb: socket buffer to update
 *
 * This is called after an ARP or IPV6 ndisc it's resolution on this
 * sk_buff. We now let protocol (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, ETH_ALEN);
                break;
        }

        return 0;
}
EXPORT_SYMBOL(eth_rebuild_header);

/**
 * eth_type_trans - determine the packet's protocol ID.
 * @skb: received socket data
 * @dev: receiving network device
 *
 * 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->dev = dev;
        skb_reset_mac_header(skb);
        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);
}
EXPORT_SYMBOL(eth_type_trans);

/**
 * eth_header_parse - extract hardware address from packet
 * @skb: packet to extract header from
 * @haddr: destination buffer
 */
int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
{
        const struct ethhdr *eth = eth_hdr(skb);
        memcpy(haddr, eth->h_source, ETH_ALEN);
        return ETH_ALEN;
}
EXPORT_SYMBOL(eth_header_parse);

/**
 * eth_header_cache - fill cache entry from neighbour
 * @neigh: source neighbour
 * @hh: destination cache entry
 * Create an Ethernet header template from the neighbour.
 */
int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh)
{
        __be16 type = hh->hh_type;
        struct ethhdr *eth;
        const struct net_device *dev = neigh->dev;

        eth = (struct ethhdr *)
            (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));

        if (type == htons(ETH_P_802_3))
                return -1;

        eth->h_proto = type;
        memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
        memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
        hh->hh_len = ETH_HLEN;
        return 0;
}
EXPORT_SYMBOL(eth_header_cache);

/**
 * eth_header_cache_update - update cache entry
 * @hh: destination cache entry
 * @dev: network device
 * @haddr: new hardware address
 *
 * Called by Address Resolution module to notify changes in address.
 */
void eth_header_cache_update(struct hh_cache *hh,
                             const struct net_device *dev,
                             const unsigned char *haddr)
{
        memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
               haddr, ETH_ALEN);
}
EXPORT_SYMBOL(eth_header_cache_update);

/**
 * eth_mac_addr - set new Ethernet hardware address
 * @dev: network device
 * @p: socket address
 * Change hardware address of device.
 *
 * This doesn't change hardware matching, so needs to be overridden
 * for most real devices.
 */
static int eth_mac_addr(struct net_device *dev, void *p)
{
        struct sockaddr *addr = p;

        if (netif_running(dev))
                return -EBUSY;
        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;
        memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
        return 0;
}

/**
 * eth_change_mtu - set new MTU size
 * @dev: network device
 * @new_mtu: new Maximum Transfer Unit
 *
 * Allow changing MTU size. Needs to be overridden for devices
 * supporting jumbo frames.
 */
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;
}

static int eth_validate_addr(struct net_device *dev)
{
        if (!is_valid_ether_addr(dev->dev_addr))
                return -EADDRNOTAVAIL;

        return 0;
}

const struct header_ops eth_header_ops ____cacheline_aligned = {
        .create         = eth_header,
        .parse          = eth_header_parse,
        .rebuild        = eth_rebuild_header,
        .cache          = eth_header_cache,
        .cache_update   = eth_header_cache_update,
};

/**
 * ether_setup - setup Ethernet network device
 * @dev: network device
 * Fill in the fields of the device structure with Ethernet-generic values.
 */
void ether_setup(struct net_device *dev)
{
        dev->header_ops         = &eth_header_ops;

        dev->change_mtu         = eth_change_mtu;
        dev->set_mac_address    = eth_mac_addr;
        dev->validate_addr      = eth_validate_addr;

        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_mq - Allocates and sets up an Ethernet device
 * @sizeof_priv: Size of additional driver-private structure to be allocated
 *      for this Ethernet device
 * @queue_count: The number of queues this device has.
 *
 * 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_mq(int sizeof_priv, unsigned int queue_count)
{
        return alloc_netdev_mq(sizeof_priv, "eth%d", ether_setup, queue_count);
}
EXPORT_SYMBOL(alloc_etherdev_mq);

static size_t _format_mac_addr(char *buf, int buflen,
                                const unsigned char *addr, int len)
{
        int i;
        char *cp = buf;

        for (i = 0; i < len; i++) {
                cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]);
                if (i == len - 1)
                        break;
                cp += strlcpy(cp, ":", buflen - (cp - buf));
        }
        return cp - buf;
}

ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
{
        size_t l;

        l = _format_mac_addr(buf, PAGE_SIZE, addr, len);
        l += strlcpy(buf + l, "\n", PAGE_SIZE - l);
        return ((ssize_t) l);
}
EXPORT_SYMBOL(sysfs_format_mac);

char *print_mac(char *buf, const unsigned char *addr)
{
        _format_mac_addr(buf, MAC_BUF_SIZE, addr, ETH_ALEN);
        return buf;
}
EXPORT_SYMBOL(print_mac);