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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
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 __user *buffer,
53 size_t *lenp, loff_t *ppos)
54{
55 int ret;
56 int range[2] = {local_port_range[0], local_port_range[1]};
57 struct ctl_table tmp = {
58 .data = &range,
59 .maxlen = sizeof(range),
60 .mode = table->mode,
61 .extra1 = &local_port_range_min,
62 .extra2 = &local_port_range_max,
63 };
64
65 ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
66
67 if (write && ret == 0) {
68 if (range[1] < range[0])
69 ret = -EINVAL;
70 else
71 set_local_port_range(range);
72 }
73
74 return ret;
75}
76
77static struct ctl_table phonet_table[] = {
78 {
79 .procname = "local_port_range",
80 .data = &local_port_range,
81 .maxlen = sizeof(local_port_range),
82 .mode = 0644,
83 .proc_handler = proc_local_port_range,
84 },
85 { }
86};
87
88int __init phonet_sysctl_init(void)
89{
90 phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);
91 return phonet_table_hrd == NULL ? -ENOMEM : 0;
92}
93
94void phonet_sysctl_exit(void)
95{
96 unregister_net_sysctl_table(phonet_table_hrd);
97}