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: R��mi 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
24static DEFINE_SEQLOCK(local_port_range_lock);
25static int local_port_range_min[2] = {0, 0};
26static int local_port_range_max[2] = {1023, 1023};
27static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
28static struct ctl_table_header *phonet_table_hrd;
29
30static 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
38void 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
51static 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
76static 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
87int __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
93void phonet_sysctl_exit(void)
94{
95	unregister_net_sysctl_table(phonet_table_hrd);
96}
97