// SPDX-License-Identifier: GPL-2.0-only/* * File: sysctl.c * * Phonet /proc/sys/net/phonet interface implementation * * Copyright (C) 2008 Nokia Corporation. * * Author: Rémi Denis-Courmont */ #include <linux/seqlock.h>#include <linux/sysctl.h>#include <linux/errno.h>#include <linux/init.h> #include <net/sock.h>#include <linux/phonet.h>#include <net/phonet/phonet.h> #define DYNAMIC_PORT_MIN	0x40#define DYNAMIC_PORT_MAX	0x7f static DEFINE_SEQLOCK(local_port_range_lock);static int local_port_range_min[2] = {0, 0};static int local_port_range_max[2] = {1023, 1023};static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};static struct ctl_table_header *phonet_table_hrd; static void set_local_port_range(int range[2]){	write_seqlock(&local_port_range_lock);	local_port_range[0] = range[0];	local_port_range[1] = range[1];	write_sequnlock(&local_port_range_lock);} void phonet_get_local_port_range(int *min, int *max){	unsigned int seq; 	do {		seq = read_seqbegin(&local_port_range_lock);		if (min)			*min = local_port_range[0];		if (max)			*max = local_port_range[1];	} while (read_seqretry(&local_port_range_lock, seq));} static int proc_local_port_range(const struct ctl_table *table, int write,				 void *buffer, size_t *lenp, loff_t *ppos){	int ret;	int range[2] = {local_port_range[0], local_port_range[1]};	struct ctl_table tmp = {		.data = &range,		.maxlen = sizeof(range),		.mode = table->mode,		.extra1 = &local_port_range_min,		.extra2 = &local_port_range_max,	}; 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos); 	if (write && ret == 0) {		if (range[1] < range[0])			ret = -EINVAL;		else			set_local_port_range(range);	} 	return ret;} static struct ctl_table phonet_table[] = {	{		.procname	= "local_port_range",		.data		= &local_port_range,		.maxlen		= sizeof(local_port_range),		.mode		= 0644,		.proc_handler	= proc_local_port_range,	},}; int __init phonet_sysctl_init(void){	phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);	return phonet_table_hrd == NULL ? -ENOMEM : 0;} void phonet_sysctl_exit(void){	unregister_net_sysctl_table(phonet_table_hrd);}