// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * 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, <stefani@lkg.dec.com>
   *
   *		fddi.c is based on previous eth.c and tr.c work by

   *			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>

   *

   *	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 = 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;

  }

  /*
   * 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);

  static const struct header_ops fddi_header_ops = {
  	.create		= fddi_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->min_mtu		= FDDI_K_SNAP_HLEN;
  	dev->max_mtu		= FDDI_K_SNAP_DLEN;

  	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);
  }
  
  /**
   * alloc_fddidev - Register FDDI device
   * @sizeof_priv: Size of additional driver-private structure to be allocated
   *	for this FDDI device
   *
   * Fill in the fields of the device structure with FDDI-generic values.
   *
   * 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_fddidev(int sizeof_priv)
  {

  	return alloc_netdev(sizeof_priv, "fddi%d", NET_NAME_UNKNOWN,
  			    fddi_setup);

  }
  EXPORT_SYMBOL(alloc_fddidev);

  
  MODULE_LICENSE("GPL");