1/*
2 * File: sysctl.c
3 *
4 * Phonet /proc/sys/net/phonet interface implementation
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * version 2 as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA
23 */
24
25#include <linux/seqlock.h>
26#include <linux/sysctl.h>
27#include <linux/errno.h>
28#include <linux/init.h>
29
30#define DYNAMIC_PORT_MIN	0x40
31#define DYNAMIC_PORT_MAX	0x7f
32
33static DEFINE_SEQLOCK(local_port_range_lock);
34static int local_port_range_min[2] = {0, 0};
35static int local_port_range_max[2] = {1023, 1023};
36static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
37static struct ctl_table_header *phonet_table_hrd;
38
39static void set_local_port_range(int range[2])
40{
41	write_seqlock(&local_port_range_lock);
42	local_port_range[0] = range[0];
43	local_port_range[1] = range[1];
44	write_sequnlock(&local_port_range_lock);
45}
46
47void phonet_get_local_port_range(int *min, int *max)
48{
49	unsigned seq;
50	do {
51		seq = read_seqbegin(&local_port_range_lock);
52		if (min)
53			*min = local_port_range[0];
54		if (max)
55			*max = local_port_range[1];
56	} while (read_seqretry(&local_port_range_lock, seq));
57}
58
59static int proc_local_port_range(ctl_table *table, int write,
60				void __user *buffer,
61				size_t *lenp, loff_t *ppos)
62{
63	int ret;
64	int range[2] = {local_port_range[0], local_port_range[1]};
65	ctl_table tmp = {
66		.data = &range,
67		.maxlen = sizeof(range),
68		.mode = table->mode,
69		.extra1 = &local_port_range_min,
70		.extra2 = &local_port_range_max,
71	};
72
73	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
74
75	if (write && ret == 0) {
76		if (range[1] < range[0])
77			ret = -EINVAL;
78		else
79			set_local_port_range(range);
80	}
81
82	return ret;
83}
84
85static struct ctl_table phonet_table[] = {
86	{
87		.procname	= "local_port_range",
88		.data		= &local_port_range,
89		.maxlen		= sizeof(local_port_range),
90		.mode		= 0644,
91		.proc_handler	= proc_local_port_range,
92	},
93	{ }
94};
95
96static struct ctl_path phonet_ctl_path[] = {
97	{ .procname = "net", },
98	{ .procname = "phonet", },
99	{ },
100};
101
102int __init phonet_sysctl_init(void)
103{
104	phonet_table_hrd = register_sysctl_paths(phonet_ctl_path, phonet_table);
105	return phonet_table_hrd == NULL ? -ENOMEM : 0;
106}
107
108void phonet_sysctl_exit(void)
109{
110	unregister_sysctl_table(phonet_table_hrd);
111}
112