/*
   * 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.
   *
   * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   */

  #include <linux/module.h>
  #include <linux/proc_fs.h>
  #include <linux/kernel.h>

  #include <linux/interrupt.h>
  #include <linux/fs.h>
  #include <linux/types.h>
  #include <linux/sysctl.h>
  #include <linux/string.h>
  #include <linux/socket.h>
  #include <linux/errno.h>
  #include <linux/fcntl.h>
  #include <linux/in.h>
  #include <linux/if_ether.h>	/* For the statistics structure. */

  #include <linux/slab.h>

  
  #include <asm/system.h>
  #include <asm/uaccess.h>
  #include <asm/io.h>
  
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/if_arp.h>
  #include <linux/skbuff.h>
  
  #include <net/ip.h>
  #include <net/arp.h>
  
  #include <net/ax25.h>
  #include <net/netrom.h>

  /*
   *	Only allow IP over NET/ROM frames through if the netrom device is up.
   */
  
  int nr_rx_ip(struct sk_buff *skb, struct net_device *dev)
  {

  	struct net_device_stats *stats = &dev->stats;

  
  	if (!netif_running(dev)) {

  		stats->rx_dropped++;

  		return 0;
  	}
  
  	stats->rx_packets++;
  	stats->rx_bytes += skb->len;
  
  	skb->protocol = htons(ETH_P_IP);
  
  	/* Spoof incoming device */
  	skb->dev      = dev;

  	skb->mac_header = skb->network_header;

  	skb_reset_network_header(skb);

  	skb->pkt_type = PACKET_HOST;

  	netif_rx(skb);

  
  	return 1;
  }

  #ifdef CONFIG_INET

  
  static int nr_rebuild_header(struct sk_buff *skb)
  {

  	unsigned char *bp = skb->data;

  	if (arp_find(bp + 7, skb))

  		return 1;

  
  	bp[6] &= ~AX25_CBIT;
  	bp[6] &= ~AX25_EBIT;
  	bp[6] |= AX25_SSSID_SPARE;
  	bp    += AX25_ADDR_LEN;
  
  	bp[6] &= ~AX25_CBIT;
  	bp[6] |= AX25_EBIT;
  	bp[6] |= AX25_SSSID_SPARE;

  	return 0;

  }
  
  #else
  
  static int nr_rebuild_header(struct sk_buff *skb)
  {
  	return 1;
  }
  
  #endif

  static int nr_header(struct sk_buff *skb, struct net_device *dev,
  		     unsigned short type,
  		     const void *daddr, const void *saddr, unsigned len)

  {
  	unsigned char *buff = skb_push(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
  
  	memcpy(buff, (saddr != NULL) ? saddr : dev->dev_addr, dev->addr_len);
  	buff[6] &= ~AX25_CBIT;
  	buff[6] &= ~AX25_EBIT;
  	buff[6] |= AX25_SSSID_SPARE;
  	buff    += AX25_ADDR_LEN;
  
  	if (daddr != NULL)
  		memcpy(buff, daddr, dev->addr_len);
  	buff[6] &= ~AX25_CBIT;
  	buff[6] |= AX25_EBIT;
  	buff[6] |= AX25_SSSID_SPARE;
  	buff    += AX25_ADDR_LEN;
  
  	*buff++ = sysctl_netrom_network_ttl_initialiser;
  
  	*buff++ = NR_PROTO_IP;
  	*buff++ = NR_PROTO_IP;
  	*buff++ = 0;
  	*buff++ = 0;
  	*buff++ = NR_PROTOEXT;
  
  	if (daddr != NULL)
  		return 37;
  
  	return -37;
  }

  static int __must_check nr_set_mac_address(struct net_device *dev, void *addr)

  {
  	struct sockaddr *sa = addr;

  	int err;
  
  	if (!memcmp(dev->dev_addr, sa->sa_data, dev->addr_len))
  		return 0;
  
  	if (dev->flags & IFF_UP) {
  		err = ax25_listen_register((ax25_address *)sa->sa_data, NULL);
  		if (err)
  			return err;

  		ax25_listen_release((ax25_address *)dev->dev_addr, NULL);

  	}

  
  	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);

  	return 0;
  }
  
  static int nr_open(struct net_device *dev)
  {

  	int err;
  
  	err = ax25_listen_register((ax25_address *)dev->dev_addr, NULL);
  	if (err)
  		return err;

  	netif_start_queue(dev);

  	return 0;
  }
  
  static int nr_close(struct net_device *dev)
  {
  	ax25_listen_release((ax25_address *)dev->dev_addr, NULL);
  	netif_stop_queue(dev);
  	return 0;
  }

  static netdev_tx_t nr_xmit(struct sk_buff *skb, struct net_device *dev)

  {

  	struct net_device_stats *stats = &dev->stats;

  	unsigned int len = skb->len;

  
  	if (!nr_route_frame(skb, NULL)) {
  		kfree_skb(skb);
  		stats->tx_errors++;

  		return NETDEV_TX_OK;

  	}
  
  	stats->tx_packets++;
  	stats->tx_bytes += len;

  	return NETDEV_TX_OK;

  }

  static const struct header_ops nr_header_ops = {
  	.create	= nr_header,
  	.rebuild= nr_rebuild_header,
  };

  static const struct net_device_ops nr_netdev_ops = {
  	.ndo_open		= nr_open,
  	.ndo_stop		= nr_close,
  	.ndo_start_xmit		= nr_xmit,
  	.ndo_set_mac_address    = nr_set_mac_address,
  };

  void nr_setup(struct net_device *dev)
  {

  	dev->mtu		= NR_MAX_PACKET_SIZE;

  	dev->netdev_ops		= &nr_netdev_ops;

  	dev->header_ops		= &nr_header_ops;

  	dev->hard_header_len	= NR_NETWORK_LEN + NR_TRANSPORT_LEN;
  	dev->addr_len		= AX25_ADDR_LEN;
  	dev->type		= ARPHRD_NETROM;

  
  	/* New-style flags. */

  	dev->flags		= IFF_NOARP;

  }