linux/net/802/hippi.c
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   1/*
   2 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3 *              operating system.  INET is implemented using the  BSD Socket
   4 *              interface as the means of communication with the user level.
   5 *
   6 *              HIPPI-type device handling.
   7 *
   8 * Version:     @(#)hippi.c     1.0.0   05/29/97
   9 *
  10 * Authors:     Ross Biro
  11 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12 *              Mark Evans, <evansmp@uhura.aston.ac.uk>
  13 *              Florian  La Roche, <rzsfl@rz.uni-sb.de>
  14 *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  15 *              Jes Sorensen, <Jes.Sorensen@cern.ch>
  16 *
  17 *              This program is free software; you can redistribute it and/or
  18 *              modify it under the terms of the GNU General Public License
  19 *              as published by the Free Software Foundation; either version
  20 *              2 of the License, or (at your option) any later version.
  21 */
  22
  23#include <linux/module.h>
  24#include <linux/types.h>
  25#include <linux/kernel.h>
  26#include <linux/string.h>
  27#include <linux/mm.h>
  28#include <linux/socket.h>
  29#include <linux/in.h>
  30#include <linux/inet.h>
  31#include <linux/netdevice.h>
  32#include <linux/hippidevice.h>
  33#include <linux/skbuff.h>
  34#include <linux/errno.h>
  35#include <net/arp.h>
  36#include <net/sock.h>
  37#include <asm/uaccess.h>
  38#include <asm/system.h>
  39
  40/*
  41 * Create the HIPPI MAC header for an arbitrary protocol layer
  42 *
  43 * saddr=NULL   means use device source address
  44 * daddr=NULL   means leave destination address (eg unresolved arp)
  45 */
  46
  47static int hippi_header(struct sk_buff *skb, struct net_device *dev,
  48                        unsigned short type,
  49                        const void *daddr, const void *saddr, unsigned len)
  50{
  51        struct hippi_hdr *hip = (struct hippi_hdr *)skb_push(skb, HIPPI_HLEN);
  52        struct hippi_cb *hcb = (struct hippi_cb *) skb->cb;
  53
  54        if (!len){
  55                len = skb->len - HIPPI_HLEN;
  56                printk("hippi_header(): length not supplied\n");
  57        }
  58
  59        /*
  60         * Due to the stupidity of the little endian byte-order we
  61         * have to set the fp field this way.
  62         */
  63        hip->fp.fixed           = htonl(0x04800018);
  64        hip->fp.d2_size         = htonl(len + 8);
  65        hip->le.fc              = 0;
  66        hip->le.double_wide     = 0;    /* only HIPPI 800 for the time being */
  67        hip->le.message_type    = 0;    /* Data PDU */
  68
  69        hip->le.dest_addr_type  = 2;    /* 12 bit SC address */
  70        hip->le.src_addr_type   = 2;    /* 12 bit SC address */
  71
  72        memcpy(hip->le.src_switch_addr, dev->dev_addr + 3, 3);
  73        memset(&hip->le.reserved, 0, 16);
  74
  75        hip->snap.dsap          = HIPPI_EXTENDED_SAP;
  76        hip->snap.ssap          = HIPPI_EXTENDED_SAP;
  77        hip->snap.ctrl          = HIPPI_UI_CMD;
  78        hip->snap.oui[0]        = 0x00;
  79        hip->snap.oui[1]        = 0x00;
  80        hip->snap.oui[2]        = 0x00;
  81        hip->snap.ethertype     = htons(type);
  82
  83        if (daddr)
  84        {
  85                memcpy(hip->le.dest_switch_addr, daddr + 3, 3);
  86                memcpy(&hcb->ifield, daddr + 2, 4);
  87                return HIPPI_HLEN;
  88        }
  89        hcb->ifield = 0;
  90        return -((int)HIPPI_HLEN);
  91}
  92
  93
  94/*
  95 * Rebuild the HIPPI MAC header. This is called after an ARP has
  96 * completed on this sk_buff. We now let ARP fill in the other fields.
  97 */
  98
  99static int hippi_rebuild_header(struct sk_buff *skb)
 100{
 101        struct hippi_hdr *hip = (struct hippi_hdr *)skb->data;
 102
 103        /*
 104         * Only IP is currently supported
 105         */
 106
 107        if(hip->snap.ethertype != htons(ETH_P_IP))
 108        {
 109                printk(KERN_DEBUG "%s: unable to resolve type %X addresses.\n",skb->dev->name,ntohs(hip->snap.ethertype));
 110                return 0;
 111        }
 112
 113        /*
 114         * We don't support dynamic ARP on HIPPI, but we use the ARP
 115         * static ARP tables to hold the I-FIELDs.
 116         */
 117        return arp_find(hip->le.daddr, skb);
 118}
 119
 120
 121/*
 122 *      Determine the packet's protocol ID.
 123 */
 124
 125__be16 hippi_type_trans(struct sk_buff *skb, struct net_device *dev)
 126{
 127        struct hippi_hdr *hip;
 128
 129        /*
 130         * This is actually wrong ... question is if we really should
 131         * set the raw address here.
 132         */
 133        skb->dev = dev;
 134        skb_reset_mac_header(skb);
 135        hip = (struct hippi_hdr *)skb_mac_header(skb);
 136        skb_pull(skb, HIPPI_HLEN);
 137
 138        /*
 139         * No fancy promisc stuff here now.
 140         */
 141
 142        return hip->snap.ethertype;
 143}
 144
 145EXPORT_SYMBOL(hippi_type_trans);
 146
 147static int hippi_change_mtu(struct net_device *dev, int new_mtu)
 148{
 149        /*
 150         * HIPPI's got these nice large MTUs.
 151         */
 152        if ((new_mtu < 68) || (new_mtu > 65280))
 153                return -EINVAL;
 154        dev->mtu = new_mtu;
 155        return(0);
 156}
 157
 158/*
 159 * For HIPPI we will actually use the lower 4 bytes of the hardware
 160 * address as the I-FIELD rather than the actual hardware address.
 161 */
 162static int hippi_mac_addr(struct net_device *dev, void *p)
 163{
 164        struct sockaddr *addr = p;
 165        if (netif_running(dev))
 166                return -EBUSY;
 167        memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
 168        return 0;
 169}
 170
 171static int hippi_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
 172{
 173        /* Never send broadcast/multicast ARP messages */
 174        p->mcast_probes = 0;
 175
 176        /* In IPv6 unicast probes are valid even on NBMA,
 177        * because they are encapsulated in normal IPv6 protocol.
 178        * Should be a generic flag.
 179        */
 180        if (p->tbl->family != AF_INET6)
 181                p->ucast_probes = 0;
 182        return 0;
 183}
 184
 185static const struct header_ops hippi_header_ops = {
 186        .create         = hippi_header,
 187        .rebuild        = hippi_rebuild_header,
 188};
 189
 190
 191static void hippi_setup(struct net_device *dev)
 192{
 193        dev->set_multicast_list         = NULL;
 194        dev->change_mtu                 = hippi_change_mtu;
 195        dev->header_ops                 = &hippi_header_ops;
 196        dev->set_mac_address            = hippi_mac_addr;
 197        dev->neigh_setup                = hippi_neigh_setup_dev;
 198
 199        /*
 200         * We don't support HIPPI `ARP' for the time being, and probably
 201         * never will unless someone else implements it. However we
 202         * still need a fake ARPHRD to make ifconfig and friends play ball.
 203         */
 204        dev->type               = ARPHRD_HIPPI;
 205        dev->hard_header_len    = HIPPI_HLEN;
 206        dev->mtu                = 65280;
 207        dev->addr_len           = HIPPI_ALEN;
 208        dev->tx_queue_len       = 25 /* 5 */;
 209        memset(dev->broadcast, 0xFF, HIPPI_ALEN);
 210
 211
 212        /*
 213         * HIPPI doesn't support broadcast+multicast and we only use
 214         * static ARP tables. ARP is disabled by hippi_neigh_setup_dev.
 215         */
 216        dev->flags = 0;
 217}
 218
 219/**
 220 * alloc_hippi_dev - Register HIPPI device
 221 * @sizeof_priv: Size of additional driver-private structure to be allocated
 222 *      for this HIPPI device
 223 *
 224 * Fill in the fields of the device structure with HIPPI-generic values.
 225 *
 226 * Constructs a new net device, complete with a private data area of
 227 * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for
 228 * this private data area.
 229 */
 230
 231struct net_device *alloc_hippi_dev(int sizeof_priv)
 232{
 233        return alloc_netdev(sizeof_priv, "hip%d", hippi_setup);
 234}
 235
 236EXPORT_SYMBOL(alloc_hippi_dev);
 237
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