fddi.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.
 *
 *      FDDI-type device handling.
 *
 * Version: @(#)fddi.c  1.0.0   08/12/96
 *
 * Authors: Lawrence V. Stefani, <[email protected]>
 *
 *      fddi.c is based on previous eth.c and tr.c work by
 *          Ross Biro
 *          Fred N. van Kempen, <[email protected]>
 *          Mark Evans, <[email protected]>
 *          Florian La Roche, <[email protected]>
 *          Alan Cox, <[email protected]>
 *
 *      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.
 *
 *  Changes
 *      Alan Cox        :   New arp/rebuild header
 *      Maciej W. Rozycki   :   IPv6 support
 */

#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/netdevice.h>
#include <linux/fddidevice.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <net/arp.h>
#include <net/sock.h>

/*
 * Create the FDDI MAC header for an arbitrary protocol layer
 *
 * saddr=NULL   means use device source address
 * daddr=NULL   means leave destination address (eg unresolved arp)
 */

static int fddi_header(struct sk_buff *skb, struct net_device *dev,
               unsigned short type,
               const void *daddr, const void *saddr, unsigned int len)
{
    int hl = FDDI_K_SNAP_HLEN;
    struct fddihdr *fddi;

    if(type != ETH_P_IP && type != ETH_P_IPV6 && type != ETH_P_ARP)
        hl=FDDI_K_8022_HLEN-3;
    fddi = (struct fddihdr *)skb_push(skb, hl);
    fddi->fc             = FDDI_FC_K_ASYNC_LLC_DEF;
    if(type == ETH_P_IP || type == ETH_P_IPV6 || type == ETH_P_ARP)
    {
        fddi->hdr.llc_snap.dsap      = FDDI_EXTENDED_SAP;
        fddi->hdr.llc_snap.ssap      = FDDI_EXTENDED_SAP;
        fddi->hdr.llc_snap.ctrl      = FDDI_UI_CMD;
        fddi->hdr.llc_snap.oui[0]    = 0x00;
        fddi->hdr.llc_snap.oui[1]    = 0x00;
        fddi->hdr.llc_snap.oui[2]    = 0x00;
        fddi->hdr.llc_snap.ethertype     = htons(type);
    }

    /* Set the source and destination hardware addresses */

    if (saddr != NULL)
        memcpy(fddi->saddr, saddr, dev->addr_len);
    else
        memcpy(fddi->saddr, dev->dev_addr, dev->addr_len);

    if (daddr != NULL)
    {
        memcpy(fddi->daddr, daddr, dev->addr_len);
        return hl;
    }

    return -hl;
}


/*
 * Rebuild the FDDI 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.
 */

static int fddi_rebuild_header(struct sk_buff   *skb)
{
    struct fddihdr *fddi = (struct fddihdr *)skb->data;

#ifdef CONFIG_INET
    if (fddi->hdr.llc_snap.ethertype == htons(ETH_P_IP))
        /* Try to get ARP to resolve the header and fill destination address */
        return arp_find(fddi->daddr, skb);
    else
#endif
    {
        printk("%s: Don't know how to resolve type %04X addresses.\n",
               skb->dev->name, ntohs(fddi->hdr.llc_snap.ethertype));
        return 0;
    }
}


/*
 * Determine the packet's protocol ID and fill in skb fields.
 * This routine is called before an incoming packet is passed
 * up.  It's used to fill in specific skb fields and to set
 * the proper pointer to the start of packet data (skb->data).
 */

__be16 fddi_type_trans(struct sk_buff *skb, struct net_device *dev)
{
    struct fddihdr *fddi = (struct fddihdr *)skb->data;
    __be16 type;

    /*
     * Set mac.raw field to point to FC byte, set data field to point
     * to start of packet data.  Assume 802.2 SNAP frames for now.
     */

    skb->dev = dev;
    skb_reset_mac_header(skb);  /* point to frame control (FC) */

    if(fddi->hdr.llc_8022_1.dsap==0xe0)
    {
        skb_pull(skb, FDDI_K_8022_HLEN-3);
        type = htons(ETH_P_802_2);
    }
    else
    {
        skb_pull(skb, FDDI_K_SNAP_HLEN);        /* adjust for 21 byte header */
        type=fddi->hdr.llc_snap.ethertype;
    }

    /* Set packet type based on destination address and flag settings */

    if (*fddi->daddr & 0x01)
    {
        if (memcmp(fddi->daddr, dev->broadcast, FDDI_K_ALEN) == 0)
            skb->pkt_type = PACKET_BROADCAST;
        else
            skb->pkt_type = PACKET_MULTICAST;
    }

    else if (dev->flags & IFF_PROMISC)
    {
        if (memcmp(fddi->daddr, dev->dev_addr, FDDI_K_ALEN))
            skb->pkt_type = PACKET_OTHERHOST;
    }

    /* Assume 802.2 SNAP frames, for now */

    return type;
}

EXPORT_SYMBOL(fddi_type_trans);

int fddi_change_mtu(struct net_device *dev, int new_mtu)
{
    if ((new_mtu < FDDI_K_SNAP_HLEN) || (new_mtu > FDDI_K_SNAP_DLEN))
        return -EINVAL;
    dev->mtu = new_mtu;
    return 0;
}
EXPORT_SYMBOL(fddi_change_mtu);

static const struct header_ops fddi_header_ops = {
    .create     = fddi_header,
    .rebuild    = fddi_rebuild_header,
};


static void fddi_setup(struct net_device *dev)
{
    dev->header_ops     = &fddi_header_ops;
    dev->type       = ARPHRD_FDDI;
    dev->hard_header_len    = FDDI_K_SNAP_HLEN+3;   /* Assume 802.2 SNAP hdr len + 3 pad bytes */
    dev->mtu        = FDDI_K_SNAP_DLEN; /* Assume max payload of 802.2 SNAP frame */
    dev->addr_len       = FDDI_K_ALEN;
    dev->tx_queue_len   = 100;          /* Long queues on FDDI */
    dev->flags      = IFF_BROADCAST | IFF_MULTICAST;

    memset(dev->broadcast, 0xFF, FDDI_K_ALEN);
}

struct net_device *alloc_fddidev(int sizeof_priv)
{
    return alloc_netdev(sizeof_priv, "fddi%d", fddi_setup);
}
EXPORT_SYMBOL(alloc_fddidev);

MODULE_LICENSE("GPL");