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
33 static DEFINE_SEQLOCK(local_port_range_lock);
34 static int local_port_range_min[2] = {0, 0};
35 static int local_port_range_max[2] = {1023, 1023};
36 static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
37 static struct ctl_table_header *phonet_table_hrd;
38
set_local_port_range(int range[2])39 static 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
phonet_get_local_port_range(int * min,int * max)47 void 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
proc_local_port_range(ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)59 static 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
85 static 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
96 static struct ctl_path phonet_ctl_path[] = {
97 { .procname = "net", },
98 { .procname = "phonet", },
99 { },
100 };
101
phonet_sysctl_init(void)102 int __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
phonet_sysctl_exit(void)108 void phonet_sysctl_exit(void)
109 {
110 unregister_sysctl_table(phonet_table_hrd);
111 }
112