incubator-nuttx/libs/libc/netdb/lib_dnsnotify.c

151 lines
4.8 KiB
C

/****************************************************************************
* libs/libc/netdb/lib_dnsnotify.c
*
* Copyright (C) 2019 Pinecone Inc. All rights reserved.
* Author: Xiang Xiao <xiaoxiang@pinecone.net>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/net/dns.h>
#include <queue.h>
#include "libc.h"
#include "netdb/lib_dns.h"
#ifdef CONFIG_NETDB_DNSCLIENT
/****************************************************************************
* Private Type Definitions
****************************************************************************/
struct dns_notify_s
{
struct dq_entry_s entry; /* Supports a doubly linked list */
dns_callback_t callback;
FAR void *arg;
};
/****************************************************************************
* Private Data
****************************************************************************/
static dq_queue_t g_dns_notify;
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: dns_register_notify
*
* Description:
* This function is called in order to receive the nameserver change.
*
****************************************************************************/
int dns_register_notify(dns_callback_t callback, FAR void *arg)
{
FAR struct dns_notify_s *notify;
notify = lib_malloc(sizeof(*notify));
if (notify == NULL)
{
return -ENOMEM;
}
notify->callback = callback;
notify->arg = arg;
dns_semtake();
dq_addlast(&notify->entry, &g_dns_notify);
dns_semgive();
/* Notify the existed nameserver */
dns_foreach_nameserver(callback, arg);
return OK;
}
/****************************************************************************
* Name: dns_unregister_notify
*
* Description:
* This function is called in order to unsubscribe the notification.
*
****************************************************************************/
int dns_unregister_notify(dns_callback_t callback, FAR void *arg)
{
FAR dq_entry_t *entry;
dns_semtake();
for (entry = dq_peek(&g_dns_notify); entry; entry = dq_next(entry))
{
FAR struct dns_notify_s *notify = (FAR struct dns_notify_s *)entry;
if (notify->callback == callback && notify->arg == arg)
{
dq_rem(&notify->entry, &g_dns_notify);
dns_semgive();
lib_free(notify);
return OK;
}
}
dns_semgive();
return -EINVAL;
}
/****************************************************************************
* Name: dns_notify_nameserver
****************************************************************************/
void dns_notify_nameserver(FAR const struct sockaddr *addr, socklen_t addrlen)
{
FAR dq_entry_t *entry;
dns_semtake();
for (entry = dq_peek(&g_dns_notify); entry; entry = dq_next(entry))
{
FAR struct dns_notify_s *notify = (FAR struct dns_notify_s *)entry;
notify->callback(notify->arg, (FAR struct sockaddr *)addr, addrlen);
}
dns_semgive();
}
#endif /* CONFIG_NETDB_DNSCLIENT */