/*
   * File: sysctl.c
   *
   * Phonet /proc/sys/net/phonet interface implementation
   *
   * Copyright (C) 2008 Nokia Corporation.
   *

   * Author: Rémi Denis-Courmont

   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * version 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   */
  
  #include <linux/seqlock.h>
  #include <linux/sysctl.h>
  #include <linux/errno.h>
  #include <linux/init.h>

  #include <net/sock.h>
  #include <linux/phonet.h>
  #include <net/phonet/phonet.h>

  #define DYNAMIC_PORT_MIN	0x40
  #define DYNAMIC_PORT_MAX	0x7f
  
  static DEFINE_SEQLOCK(local_port_range_lock);
  static int local_port_range_min[2] = {0, 0};
  static int local_port_range_max[2] = {1023, 1023};
  static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
  static struct ctl_table_header *phonet_table_hrd;
  
  static void set_local_port_range(int range[2])
  {
  	write_seqlock(&local_port_range_lock);
  	local_port_range[0] = range[0];
  	local_port_range[1] = range[1];
  	write_sequnlock(&local_port_range_lock);
  }
  
  void phonet_get_local_port_range(int *min, int *max)
  {

  	unsigned int seq;

  	do {
  		seq = read_seqbegin(&local_port_range_lock);
  		if (min)
  			*min = local_port_range[0];
  		if (max)
  			*max = local_port_range[1];
  	} while (read_seqretry(&local_port_range_lock, seq));
  }

  static int proc_local_port_range(struct ctl_table *table, int write,

  				void __user *buffer,
  				size_t *lenp, loff_t *ppos)
  {
  	int ret;
  	int range[2] = {local_port_range[0], local_port_range[1]};

  	struct ctl_table tmp = {

  		.data = &range,
  		.maxlen = sizeof(range),
  		.mode = table->mode,
  		.extra1 = &local_port_range_min,
  		.extra2 = &local_port_range_max,
  	};

  	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);

  
  	if (write && ret == 0) {
  		if (range[1] < range[0])
  			ret = -EINVAL;
  		else
  			set_local_port_range(range);
  	}
  
  	return ret;
  }
  
  static struct ctl_table phonet_table[] = {
  	{

  		.procname	= "local_port_range",
  		.data		= &local_port_range,
  		.maxlen		= sizeof(local_port_range),
  		.mode		= 0644,

  		.proc_handler	= proc_local_port_range,

  	},

  	{ }

  };

  int __init phonet_sysctl_init(void)
  {

  	phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);

  	return phonet_table_hrd == NULL ? -ENOMEM : 0;
  }
  
  void phonet_sysctl_exit(void)
  {

  	unregister_net_sysctl_table(phonet_table_hrd);

  }