net/802/hippi.c

   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/sched.h>
  27 #include <linux/string.h>
  28 #include <linux/mm.h>
  29 #include <linux/socket.h>
  30 #include <linux/in.h>
  31 #include <linux/inet.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/hippidevice.h>
  34 #include <linux/skbuff.h>
  35 #include <linux/errno.h>
  36 #include <net/arp.h>
  37 #include <net/sock.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/checksum.h>
  40 #include <asm/system.h>
  41
  42 /*
  43  * Create the HIPPI MAC header for an arbitrary protocol layer
  44  *
  45  * saddr=NULL   means use device source address
  46  * daddr=NULL   means leave destination address (eg unresolved arp)
  47  */
  48
  49 static int hippi_header(struct sk_buff *skb, struct net_device *dev,
  50                         unsigned short type, void *daddr, void *saddr,
  51                         unsigned len)
  52 {
  53         struct hippi_hdr *hip = (struct hippi_hdr *)skb_push(skb, HIPPI_HLEN);
  54
  55         if (!len){
  56                 len = skb->len - HIPPI_HLEN;
  57                 printk("hippi_header(): length not supplied\n");
  58         }
  59
  60         /*
  61          * Due to the stupidity of the little endian byte-order we
  62          * have to set the fp field this way.
  63          */
  64         hip->fp.fixed           = __constant_htonl(0x04800018);
  65         hip->fp.d2_size         = htonl(len + 8);
  66         hip->le.fc              = 0;
  67         hip->le.double_wide     = 0;    /* only HIPPI 800 for the time being */
  68         hip->le.message_type    = 0;    /* Data PDU */
  69
  70         hip->le.dest_addr_type  = 2;    /* 12 bit SC address */
  71         hip->le.src_addr_type   = 2;    /* 12 bit SC address */
  72
  73         memcpy(hip->le.src_switch_addr, dev->dev_addr + 3, 3);
  74         memset(&hip->le.reserved, 0, 16);
  75
  76         hip->snap.dsap          = HIPPI_EXTENDED_SAP;
  77         hip->snap.ssap          = HIPPI_EXTENDED_SAP;
  78         hip->snap.ctrl          = HIPPI_UI_CMD;
  79         hip->snap.oui[0]        = 0x00;
  80         hip->snap.oui[1]        = 0x00;
  81         hip->snap.oui[2]        = 0x00;
  82         hip->snap.ethertype     = htons(type);
  83
  84         if (daddr)
  85         {
  86                 memcpy(hip->le.dest_switch_addr, daddr + 3, 3);
  87                 memcpy(&skb->private.ifield, daddr + 2, 4);
  88                 return HIPPI_HLEN;
  89         }
  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
  99 static 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 != __constant_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 unsigned short hippi_type_trans(struct sk_buff *skb, struct net_device *dev)
 126 {
 127         struct hippi_hdr *hip;
 128
 129         hip = (struct hippi_hdr *) skb->data;
 130
 131         /*
 132          * This is actually wrong ... question is if we really should
 133          * set the raw address here.
 134          */
 135          skb->mac.raw = skb->data;
 136          skb_pull(skb, HIPPI_HLEN);
 137
 138         /*
 139          * No fancy promisc stuff here now.
 140          */
 141
 142         return hip->snap.ethertype;
 143 }
 144
 145 EXPORT_SYMBOL(hippi_type_trans);
 146
 147 static 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  */
 162 static 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
 171 static 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
 185 static void hippi_setup(struct net_device *dev)
 186 {
 187         dev->set_multicast_list         = NULL;
 188         dev->change_mtu                 = hippi_change_mtu;
 189         dev->hard_header                = hippi_header;
 190         dev->rebuild_header             = hippi_rebuild_header;
 191         dev->set_mac_address            = hippi_mac_addr;
 192         dev->hard_header_parse          = NULL;
 193         dev->hard_header_cache          = NULL;
 194         dev->header_cache_update        = NULL;
 195         dev->neigh_setup                = hippi_neigh_setup_dev;
 196
 197         /*
 198          * We don't support HIPPI `ARP' for the time being, and probably
 199          * never will unless someone else implements it. However we
 200          * still need a fake ARPHRD to make ifconfig and friends play ball.
 201          */
 202         dev->type               = ARPHRD_HIPPI;
 203         dev->hard_header_len    = HIPPI_HLEN;
 204         dev->mtu                = 65280;
 205         dev->addr_len           = HIPPI_ALEN;
 206         dev->tx_queue_len       = 25 /* 5 */;
 207         memset(dev->broadcast, 0xFF, HIPPI_ALEN);
 208
 209
 210         /*
 211          * HIPPI doesn't support broadcast+multicast and we only use
 212          * static ARP tables. ARP is disabled by hippi_neigh_setup_dev.
 213          */
 214         dev->flags = 0;
 215 }
 216
 217 /**
 218  * alloc_hippi_dev - Register HIPPI device
 219  * @sizeof_priv: Size of additional driver-private structure to be allocated
 220  *      for this HIPPI device
 221  *
 222  * Fill in the fields of the device structure with HIPPI-generic values.
 223  *
 224  * Constructs a new net device, complete with a private data area of
 225  * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for
 226  * this private data area.
 227  */
 228
 229 struct net_device *alloc_hippi_dev(int sizeof_priv)
 230 {
 231         return alloc_netdev(sizeof_priv, "hip%d", hippi_setup);
 232 }
 233
 234 EXPORT_SYMBOL(alloc_hippi_dev);