nuttx-apps/netutils/dnsclient/dns_resolver.c

124 lines
4.6 KiB
C

/****************************************************************************
* apps/netutils/dnsclient/dns_resolver.c
* DNS host name to IP address resolver.
*
* The uIP DNS resolver functions are used to lookup a hostname and
* map it to a numerical IP address. It maintains a list of resolved
* hostnames that can be queried. New hostnames can be resolved using the
* dns_whois() function.
*
* Copyright (C) 2007, 2009, 2012, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Based heavily on portions of uIP:
*
* Author: Adam Dunkels <adam@dunkels.com>
* Copyright (c) 2002-2003, Adam Dunkels.
* All rights reserved.
*
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <netinet/in.h>
#include <apps/netutils/dnsclient.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
static int g_sockfd = -1;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: dns_bind
*
* Description:
* Initialize the DNS resolver using an internal, share-able socket.
*
****************************************************************************/
int dns_bind(void)
{
return dns_bind_sock(&g_sockfd);
}
/****************************************************************************
* Name: dns_query
*
* Description:
* Using the internal DNS resolver socket, look up the the 'hostname', and
* return its IP address in 'ipaddr'
*
* Returned Value:
* Returns zero (OK) if the query was successful.
*
****************************************************************************/
int dns_query(FAR const char *hostname, FAR in_addr_t *ipaddr)
{
return dns_query_sock(g_sockfd, hostname, ipaddr);
}
/****************************************************************************
* Name: dns_whois
*
* Description:
* Get the binding for 'name' using the DNS server accessed via the DNS
* resolvers internal socket.
*
****************************************************************************/
#ifdef CONFIG_NETUTILS_DNSCLIENT_IPv6
int dns_whois(FAR const char *name, FAR struct sockaddr_in6 *addr)
#else
int dns_whois(FAR const char *name, FAR struct sockaddr_in *addr)
#endif
{
return dns_whois_socket(g_sockfd, name, addr);
}