net/phonet/sysctl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * File: sysctl.c
   4  *
   5  * Phonet /proc/sys/net/phonet interface implementation
   6  *
   7  * Copyright (C) 2008 Nokia Corporation.
   8  *
   9  * Author: Rémi Denis-Courmont
  10  */
  11
  12 #include <linux/seqlock.h>
  13 #include <linux/sysctl.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16
  17 #include <net/sock.h>
  18 #include <linux/phonet.h>
  19 #include <net/phonet/phonet.h>
  20
  21 #define DYNAMIC_PORT_MIN        0x40
  22 #define DYNAMIC_PORT_MAX        0x7f
  23
  24 static DEFINE_SEQLOCK(local_port_range_lock);
  25 static int local_port_range_min[2] = {0, 0};
  26 static int local_port_range_max[2] = {1023, 1023};
  27 static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
  28 static struct ctl_table_header *phonet_table_hrd;
  29
  30 static void set_local_port_range(int range[2])
  31 {
  32         write_seqlock(&local_port_range_lock);
  33         local_port_range[0] = range[0];
  34         local_port_range[1] = range[1];
  35         write_sequnlock(&local_port_range_lock);
  36 }
  37
  38 void phonet_get_local_port_range(int *min, int *max)
  39 {
  40         unsigned int seq;
  41
  42         do {
  43                 seq = read_seqbegin(&local_port_range_lock);
  44                 if (min)
  45                         *min = local_port_range[0];
  46                 if (max)
  47                         *max = local_port_range[1];
  48         } while (read_seqretry(&local_port_range_lock, seq));
  49 }
  50
  51 static int proc_local_port_range(struct ctl_table *table, int write,
  52                                  void *buffer, size_t *lenp, loff_t *ppos)
  53 {
  54         int ret;
  55         int range[2] = {local_port_range[0], local_port_range[1]};
  56         struct ctl_table tmp = {
  57                 .data = &range,
  58                 .maxlen = sizeof(range),
  59                 .mode = table->mode,
  60                 .extra1 = &local_port_range_min,
  61                 .extra2 = &local_port_range_max,
  62         };
  63
  64         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
  65
  66         if (write && ret == 0) {
  67                 if (range[1] < range[0])
  68                         ret = -EINVAL;
  69                 else
  70                         set_local_port_range(range);
  71         }
  72
  73         return ret;
  74 }
  75
  76 static struct ctl_table phonet_table[] = {
  77         {
  78                 .procname       = "local_port_range",
  79                 .data           = &local_port_range,
  80                 .maxlen         = sizeof(local_port_range),
  81                 .mode           = 0644,
  82                 .proc_handler   = proc_local_port_range,
  83         },
  84         { }
  85 };
  86
  87 int __init phonet_sysctl_init(void)
  88 {
  89         phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);
  90         return phonet_table_hrd == NULL ? -ENOMEM : 0;
  91 }
  92
  93 void phonet_sysctl_exit(void)
  94 {
  95         unregister_net_sysctl_table(phonet_table_hrd);
  96 }