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

  /*

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

  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/socket.h>

  #include <linux/slab.h>

  #include <linux/in.h>
  #include <linux/kernel.h>

  #include <linux/timer.h>
  #include <linux/string.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
  #include <linux/spinlock.h>
  #include <net/ax25.h>
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <linux/skbuff.h>
  #include <net/sock.h>

  #include <linux/uaccess.h>

  #include <linux/fcntl.h>
  #include <linux/mm.h>
  #include <linux/interrupt.h>
  #include <linux/init.h>
  
  ax25_dev *ax25_dev_list;
  DEFINE_SPINLOCK(ax25_dev_lock);
  
  ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
  {
  	ax25_dev *ax25_dev, *res = NULL;
  
  	spin_lock_bh(&ax25_dev_lock);
  	for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
  		if (ax25cmp(addr, (ax25_address *)ax25_dev->dev->dev_addr) == 0) {
  			res = ax25_dev;
  		}
  	spin_unlock_bh(&ax25_dev_lock);
  
  	return res;
  }
  
  /*
   *	This is called when an interface is brought up. These are
   *	reasonable defaults.
   */
  void ax25_dev_device_up(struct net_device *dev)
  {
  	ax25_dev *ax25_dev;

  	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {

  		printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory
  ");
  		return;
  	}

  	dev->ax25_ptr     = ax25_dev;
  	ax25_dev->dev     = dev;
  	dev_hold(dev);
  	ax25_dev->forward = NULL;
  
  	ax25_dev->values[AX25_VALUES_IPDEFMODE] = AX25_DEF_IPDEFMODE;
  	ax25_dev->values[AX25_VALUES_AXDEFMODE] = AX25_DEF_AXDEFMODE;
  	ax25_dev->values[AX25_VALUES_BACKOFF]   = AX25_DEF_BACKOFF;
  	ax25_dev->values[AX25_VALUES_CONMODE]   = AX25_DEF_CONMODE;
  	ax25_dev->values[AX25_VALUES_WINDOW]    = AX25_DEF_WINDOW;
  	ax25_dev->values[AX25_VALUES_EWINDOW]   = AX25_DEF_EWINDOW;
  	ax25_dev->values[AX25_VALUES_T1]        = AX25_DEF_T1;
  	ax25_dev->values[AX25_VALUES_T2]        = AX25_DEF_T2;
  	ax25_dev->values[AX25_VALUES_T3]        = AX25_DEF_T3;
  	ax25_dev->values[AX25_VALUES_IDLE]	= AX25_DEF_IDLE;
  	ax25_dev->values[AX25_VALUES_N2]        = AX25_DEF_N2;
  	ax25_dev->values[AX25_VALUES_PACLEN]	= AX25_DEF_PACLEN;
  	ax25_dev->values[AX25_VALUES_PROTOCOL]  = AX25_DEF_PROTOCOL;
  	ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;
  
  #if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)

  	ax25_ds_setup_timer(ax25_dev);

  #endif
  
  	spin_lock_bh(&ax25_dev_lock);
  	ax25_dev->next = ax25_dev_list;
  	ax25_dev_list  = ax25_dev;
  	spin_unlock_bh(&ax25_dev_lock);

  	ax25_register_dev_sysctl(ax25_dev);

  }
  
  void ax25_dev_device_down(struct net_device *dev)
  {
  	ax25_dev *s, *ax25_dev;
  
  	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
  		return;

  	ax25_unregister_dev_sysctl(ax25_dev);

  
  	spin_lock_bh(&ax25_dev_lock);
  
  #ifdef CONFIG_AX25_DAMA_SLAVE
  	ax25_ds_del_timer(ax25_dev);
  #endif
  
  	/*
  	 *	Remove any packet forwarding that points to this device.
  	 */
  	for (s = ax25_dev_list; s != NULL; s = s->next)
  		if (s->forward == dev)
  			s->forward = NULL;
  
  	if ((s = ax25_dev_list) == ax25_dev) {
  		ax25_dev_list = s->next;
  		spin_unlock_bh(&ax25_dev_lock);

  		dev->ax25_ptr = NULL;

  		dev_put(dev);
  		kfree(ax25_dev);

  		return;
  	}
  
  	while (s != NULL && s->next != NULL) {
  		if (s->next == ax25_dev) {
  			s->next = ax25_dev->next;
  			spin_unlock_bh(&ax25_dev_lock);

  			dev->ax25_ptr = NULL;

  			dev_put(dev);
  			kfree(ax25_dev);

  			return;
  		}
  
  		s = s->next;
  	}
  	spin_unlock_bh(&ax25_dev_lock);
  	dev->ax25_ptr = NULL;

  }
  
  int ax25_fwd_ioctl(unsigned int cmd, struct ax25_fwd_struct *fwd)
  {
  	ax25_dev *ax25_dev, *fwd_dev;
  
  	if ((ax25_dev = ax25_addr_ax25dev(&fwd->port_from)) == NULL)
  		return -EINVAL;
  
  	switch (cmd) {
  	case SIOCAX25ADDFWD:
  		if ((fwd_dev = ax25_addr_ax25dev(&fwd->port_to)) == NULL)
  			return -EINVAL;
  		if (ax25_dev->forward != NULL)
  			return -EINVAL;
  		ax25_dev->forward = fwd_dev->dev;
  		break;
  
  	case SIOCAX25DELFWD:
  		if (ax25_dev->forward == NULL)
  			return -EINVAL;
  		ax25_dev->forward = NULL;
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  struct net_device *ax25_fwd_dev(struct net_device *dev)
  {
  	ax25_dev *ax25_dev;
  
  	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
  		return dev;
  
  	if (ax25_dev->forward == NULL)
  		return dev;
  
  	return ax25_dev->forward;
  }
  
  /*
   *	Free all memory associated with device structures.
   */
  void __exit ax25_dev_free(void)
  {
  	ax25_dev *s, *ax25_dev;
  
  	spin_lock_bh(&ax25_dev_lock);
  	ax25_dev = ax25_dev_list;
  	while (ax25_dev != NULL) {
  		s        = ax25_dev;
  		dev_put(ax25_dev->dev);
  		ax25_dev = ax25_dev->next;
  		kfree(s);
  	}
  	ax25_dev_list = NULL;
  	spin_unlock_bh(&ax25_dev_lock);
  }