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
set_local_port_range(int range[2])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
phonet_get_local_port_range(int * min,int * max)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
proc_local_port_range(const struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)51 static int proc_local_port_range(const 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
phonet_sysctl_init(void)86 int __init phonet_sysctl_init(void)
87 {
88 phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);
89 return phonet_table_hrd == NULL ? -ENOMEM : 0;
90 }
91
phonet_sysctl_exit(void)92 void phonet_sysctl_exit(void)
93 {
94 unregister_net_sysctl_table(phonet_table_hrd);
95 }
96