LXR linux/net/phonet/sysctl.c

   1/*
   2 * File: sysctl.c
   3 *
   4 * Phonet /proc/sys/net/phonet interface implementation
   5 *
   6 * Copyright (C) 2008 Nokia Corporation.
   7 *
   8 * Author: Rémi Denis-Courmont
   9 *
  10 * This program is free software; you can redistribute it and/or
  11 * modify it under the terms of the GNU General Public License
  12 * version 2 as published by the Free Software Foundation.
  13 *
  14 * This program is distributed in the hope that it will be useful, but
  15 * WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 * General Public License for more details.
  18 *
  19 * You should have received a copy of the GNU General Public License
  20 * along with this program; if not, write to the Free Software
  21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  22 * 02110-1301 USA
  23 */
  24
  25#include <linux/seqlock.h>
  26#include <linux/sysctl.h>
  27#include <linux/errno.h>
  28#include <linux/init.h>
  29
  30#include <net/sock.h>
  31#include <linux/phonet.h>
  32#include <net/phonet/phonet.h>
  33
  34#define DYNAMIC_PORT_MIN        0x40
  35#define DYNAMIC_PORT_MAX        0x7f
  36
  37static DEFINE_SEQLOCK(local_port_range_lock);
  38static int local_port_range_min[2] = {0, 0};
  39static int local_port_range_max[2] = {1023, 1023};
  40static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
  41static struct ctl_table_header *phonet_table_hrd;
  42
  43static void set_local_port_range(int range[2])
  44{
  45        write_seqlock(&local_port_range_lock);
  46        local_port_range[0] = range[0];
  47        local_port_range[1] = range[1];
  48        write_sequnlock(&local_port_range_lock);
  49}
  50
  51void phonet_get_local_port_range(int *min, int *max)
  52{
  53        unsigned int seq;
  54
  55        do {
  56                seq = read_seqbegin(&local_port_range_lock);
  57                if (min)
  58                        *min = local_port_range[0];
  59                if (max)
  60                        *max = local_port_range[1];
  61        } while (read_seqretry(&local_port_range_lock, seq));
  62}
  63
  64static int proc_local_port_range(struct ctl_table *table, int write,
  65                                void __user *buffer,
  66                                size_t *lenp, loff_t *ppos)
  67{
  68        int ret;
  69        int range[2] = {local_port_range[0], local_port_range[1]};
  70        struct ctl_table tmp = {
  71                .data = &range,
  72                .maxlen = sizeof(range),
  73                .mode = table->mode,
  74                .extra1 = &local_port_range_min,
  75                .extra2 = &local_port_range_max,
  76        };
  77
  78        ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
  79
  80        if (write && ret == 0) {
  81                if (range[1] < range[0])
  82                        ret = -EINVAL;
  83                else
  84                        set_local_port_range(range);
  85        }
  86
  87        return ret;
  88}
  89
  90static struct ctl_table phonet_table[] = {
  91        {
  92                .procname       = "local_port_range",
  93                .data           = &local_port_range,
  94                .maxlen         = sizeof(local_port_range),
  95                .mode           = 0644,
  96                .proc_handler   = proc_local_port_range,
  97        },
  98        { }
  99};
 100
 101int __init phonet_sysctl_init(void)
 102{
 103        phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);
 104        return phonet_table_hrd == NULL ? -ENOMEM : 0;
 105}
 106
 107void phonet_sysctl_exit(void)
 108{
 109        unregister_net_sysctl_table(phonet_table_hrd);
 110}
 111