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 37 static DEFINE_SEQLOCK(local_port_range_lock); 38 static int local_port_range_min[2] = {0, 0}; 39 static int local_port_range_max[2] = {1023, 1023}; 40 static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX}; 41 static struct ctl_table_header *phonet_table_hrd; 42 43 static 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 51 void 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 64 static 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 90 static 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 }; 100 101 int __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 } 106 107 void phonet_sysctl_exit(void) 108 { 109 unregister_net_sysctl_table(phonet_table_hrd); 110 } 111