1/*
2 * File: sysctl.c
3 *
4 * Phonet /proc/sys/net/phonet interface implementation
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Author: Rémi Denis-Courmont
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#include <net/sock.h>
31#include <linux/phonet.h>
32#include <net/phonet/phonet.h>
33
34#define DYNAMIC_PORT_MIN	0x40
35#define DYNAMIC_PORT_MAX	0x7f
36
37static DEFINE_SEQLOCK(local_port_range_lock);
38static int local_port_range_min[2] = {0, 0};
39static int local_port_range_max[2] = {1023, 1023};
40static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
41static struct ctl_table_header *phonet_table_hrd;
42
43static void set_local_port_range(int range[2])
44{
45	write_seqlock(&local_port_range_lock);
46	local_port_range[0] = range[0];
47	local_port_range[1] = range[1];
48	write_sequnlock(&local_port_range_lock);
49}
50
51void phonet_get_local_port_range(int *min, int *max)
52{
53	unsigned int seq;
54
55	do {
56		seq = read_seqbegin(&local_port_range_lock);
57		if (min)
58			*min = local_port_range[0];
59		if (max)
60			*max = local_port_range[1];
61	} while (read_seqretry(&local_port_range_lock, seq));
62}
63
64static int proc_local_port_range(struct ctl_table *table, int write,
65				void __user *buffer,
66				size_t *lenp, loff_t *ppos)
67{
68	int ret;
69	int range[2] = {local_port_range[0], local_port_range[1]};
70	struct ctl_table tmp = {
71		.data = &range,
72		.maxlen = sizeof(range),
73		.mode = table->mode,
74		.extra1 = &local_port_range_min,
75		.extra2 = &local_port_range_max,
76	};
77
78	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
79
80	if (write && ret == 0) {
81		if (range[1] < range[0])
82			ret = -EINVAL;
83		else
84			set_local_port_range(range);
85	}
86
87	return ret;
88}
89
90static struct ctl_table phonet_table[] = {
91	{
92		.procname	= "local_port_range",
93		.data		= &local_port_range,
94		.maxlen		= sizeof(local_port_range),
95		.mode		= 0644,
96		.proc_handler	= proc_local_port_range,
97	},
98	{ }
99};
100
101int __init phonet_sysctl_init(void)
102{
103	phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);
104	return phonet_table_hrd == NULL ? -ENOMEM : 0;
105}
106
107void phonet_sysctl_exit(void)
108{
109	unregister_net_sysctl_table(phonet_table_hrd);
110}
111