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 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 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 59 static int proc_local_port_range(ctl_table *table, int write, struct file *filp, 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, filp, 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 .ctl_name = CTL_UNNUMBERED, 88 .procname = "local_port_range", 89 .data = &local_port_range, 90 .maxlen = sizeof(local_port_range), 91 .mode = 0644, 92 .proc_handler = proc_local_port_range, 93 .strategy = NULL, 94 }, 95 { .ctl_name = 0 } 96 }; 97 98 static struct ctl_path phonet_ctl_path[] = { 99 { .procname = "net", .ctl_name = CTL_NET, }, 100 { .procname = "phonet", .ctl_name = CTL_UNNUMBERED, }, 101 { }, 102 }; 103 104 int __init phonet_sysctl_init(void) 105 { 106 phonet_table_hrd = register_sysctl_paths(phonet_ctl_path, phonet_table); 107 return phonet_table_hrd == NULL ? -ENOMEM : 0; 108 } 109 110 void phonet_sysctl_exit(void) 111 { 112 unregister_sysctl_table(phonet_table_hrd); 113 } 114