1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * File: sysctl.c 4 * 5 * Phonet /proc/sys/net/phonet interface implementation 6 * 7 * Copyright (C) 2008 Nokia Corporation. 8 * 9 * Author: Rémi Denis-Courmont 10 */ 11 12 #include <linux/seqlock.h> 13 #include <linux/sysctl.h> 14 #include <linux/errno.h> 15 #include <linux/init.h> 16 17 #include <net/sock.h> 18 #include <linux/phonet.h> 19 #include <net/phonet/phonet.h> 20 21 #define DYNAMIC_PORT_MIN 0x40 22 #define DYNAMIC_PORT_MAX 0x7f 23 24 static DEFINE_SEQLOCK(local_port_range_lock); 25 static int local_port_range_min[2] = {0, 0}; 26 static int local_port_range_max[2] = {1023, 1023}; 27 static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX}; 28 static struct ctl_table_header *phonet_table_hrd; 29 30 static void set_local_port_range(int range[2]) 31 { 32 write_seqlock(&local_port_range_lock); 33 local_port_range[0] = range[0]; 34 local_port_range[1] = range[1]; 35 write_sequnlock(&local_port_range_lock); 36 } 37 38 void phonet_get_local_port_range(int *min, int *max) 39 { 40 unsigned int seq; 41 42 do { 43 seq = read_seqbegin(&local_port_range_lock); 44 if (min) 45 *min = local_port_range[0]; 46 if (max) 47 *max = local_port_range[1]; 48 } while (read_seqretry(&local_port_range_lock, seq)); 49 } 50 51 static int proc_local_port_range(struct ctl_table *table, int write, 52 void __user *buffer, 53 size_t *lenp, loff_t *ppos) 54 { 55 int ret; 56 int range[2] = {local_port_range[0], local_port_range[1]}; 57 struct ctl_table tmp = { 58 .data = &range, 59 .maxlen = sizeof(range), 60 .mode = table->mode, 61 .extra1 = &local_port_range_min, 62 .extra2 = &local_port_range_max, 63 }; 64 65 ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos); 66 67 if (write && ret == 0) { 68 if (range[1] < range[0]) 69 ret = -EINVAL; 70 else 71 set_local_port_range(range); 72 } 73 74 return ret; 75 } 76 77 static struct ctl_table phonet_table[] = { 78 { 79 .procname = "local_port_range", 80 .data = &local_port_range, 81 .maxlen = sizeof(local_port_range), 82 .mode = 0644, 83 .proc_handler = proc_local_port_range, 84 }, 85 { } 86 }; 87 88 int __init phonet_sysctl_init(void) 89 { 90 phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table); 91 return phonet_table_hrd == NULL ? -ENOMEM : 0; 92 } 93 94 void phonet_sysctl_exit(void) 95 { 96 unregister_net_sysctl_table(phonet_table_hrd); 97 } 98