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(sl: &local_port_range_lock);
33 local_port_range[0] = range[0];
34 local_port_range[1] = range[1];
35 write_sequnlock(sl: &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(sl: &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(sl: &local_port_range_lock, start: 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(header: phonet_table_hrd);
96}
97

source code of linux/net/phonet/sysctl.c