The rest of the resolv->DNS client naming change: Renamed directories and header files

4 files changed, 858 insertions, 0 deletions

diff --git a/apps/netutils/dnsclient/.gitignore b/apps/netutils/dnsclient/.gitignore
new file mode 100644
index 000000000..f21c854d1
--- /dev/null
+++ b/apps/netutils/dnsclient/.gitignore
@@ -0,0 +1,6 @@
+/.built
+/.depend
+/Make.dep
+/*.src
+/*.obj
+/*.lst
diff --git a/apps/netutils/dnsclient/Kconfig b/apps/netutils/dnsclient/Kconfig
new file mode 100644
index 000000000..77b2bd634
--- /dev/null
+++ b/apps/netutils/dnsclient/Kconfig
@@ -0,0 +1,29 @@
+#
+# For a description of the syntax of this configuration file,
+# see misc/tools/kconfig-language.txt.
+#
+
+config NETUTILS_DNSCLIENT
+	bool "DNS Name resolution"
+	default n
+	depends on NET && NET_UDP && NET_BROADCAST
+	---help---
+		Enable support for the name resolution.
+
+if NETUTILS_DNSCLIENT
+
+config NETUTILS_DNSCLIENT_ENTRIES
+	int "Number of DNS resolver entries"
+	default 8
+	---help---
+		Number of DNS resolver entries.  Default: 8
+
+config NETUTILS_DNSCLIENT_MAXRESPONSE
+	int "Max response size"
+	default 96
+	---help---
+		This setting determines the maximum size of response message that
+		can be received by the DNS resolver.  The default is 96 but may
+		need to be larger on enterprise networks (perhaps 176).
+
+endif # NETUTILS_DNSCLIENT
diff --git a/apps/netutils/dnsclient/Makefile b/apps/netutils/dnsclient/Makefile
new file mode 100644
index 000000000..076fa5290
--- /dev/null
+++ b/apps/netutils/dnsclient/Makefile
@@ -0,0 +1,100 @@
+############################################################################
+# apps/netutils/dnsclient/Makefile
+#
+#   Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <gnutt@nuttx.org>
+#
+# 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.
+#
+############################################################################
+
+-include $(TOPDIR)/.config
+-include $(TOPDIR)/Make.defs
+include $(APPDIR)/Make.defs
+
+# DNS Resolver library
+
+ASRCS		=
+CSRCS		= 
+
+ifeq ($(CONFIG_NET_UDP),y)
+CSRCS		= dnsclient.c
+endif
+
+AOBJS		= $(ASRCS:.S=$(OBJEXT))
+COBJS		= $(CSRCS:.c=$(OBJEXT))
+
+SRCS		= $(ASRCS) $(CSRCS)
+OBJS		= $(AOBJS) $(COBJS)
+
+ifeq ($(CONFIG_WINDOWS_NATIVE),y)
+  BIN		= ..\..\libapps$(LIBEXT)
+else
+ifeq ($(WINTOOL),y)
+  BIN		= ..\\..\\libapps$(LIBEXT)
+else
+  BIN		= ../../libapps$(LIBEXT)
+endif
+endif
+
+ROOTDEPPATH	= --dep-path .
+
+# Common build
+
+VPATH		= 
+
+all: .built
+.PHONY: context depend clean distclean
+
+$(AOBJS): %$(OBJEXT): %.S
+	$(call ASSEMBLE, $<, $@)
+
+$(COBJS): %$(OBJEXT): %.c
+	$(call COMPILE, $<, $@)
+
+.built: $(OBJS)
+	$(call ARCHIVE, $(BIN), $(OBJS))
+	$(Q) touch .built
+
+context:
+
+.depend: Makefile $(SRCS)
+	$(Q) $(MKDEP) $(ROOTDEPPATH) "$(CC)" -- $(CFLAGS) -- $(SRCS) >Make.dep
+	$(Q) touch $@
+
+depend: .depend
+
+clean:
+	$(call DELFILE, .built)
+	$(call CLEAN)
+
+distclean: clean
+	$(call DELFILE, Make.dep)
+	$(call DELFILE, .depend)
+
+-include Make.dep
diff --git a/apps/netutils/dnsclient/dnsclient.c b/apps/netutils/dnsclient/dnsclient.c
new file mode 100644
index 000000000..b2dbae8c6
--- /dev/null
+++ b/apps/netutils/dnsclient/dnsclient.c
@@ -0,0 +1,723 @@
+/****************************************************************************
+ * apps/netutils/dnsclient/dnsclient.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 <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+#include <errno.h>
+#include <debug.h>
+#include <assert.h>
+
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+#include <apps/netutils/dnsclient.h>
+#include <apps/netutils/uiplib.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifndef CONFIG_NETUTILS_DNSCLIENT_ENTRIES
+#  define RESOLV_ENTRIES 4
+#else /* CONFIG_NETUTILS_DNSCLIENT_ENTRIES */
+#  define RESOLV_ENTRIES CONFIG_NETUTILS_DNSCLIENT_ENTRIES
+#endif /* CONFIG_NETUTILS_DNSCLIENT_ENTRIES */
+
+#ifndef NULL
+#  define NULL (void *)0
+#endif /* NULL */
+
+/* The maximum number of retries when asking for a name */
+
+#define MAX_RETRIES 8
+
+#define DNS_FLAG1_RESPONSE        0x80
+#define DNS_FLAG1_OPCODE_STATUS   0x10
+#define DNS_FLAG1_OPCODE_INVERSE  0x08
+#define DNS_FLAG1_OPCODE_STANDARD 0x00
+#define DNS_FLAG1_AUTHORATIVE     0x04
+#define DNS_FLAG1_TRUNC           0x02
+#define DNS_FLAG1_RD              0x01
+#define DNS_FLAG2_RA              0x80
+#define DNS_FLAG2_ERR_MASK        0x0f
+#define DNS_FLAG2_ERR_NONE        0x00
+#define DNS_FLAG2_ERR_NAME        0x03
+
+#define SEND_BUFFER_SIZE 64
+
+#ifdef CONFIG_NETUTILS_DNSCLIENT_MAXRESPONSE
+#  define RECV_BUFFER_SIZE CONFIG_NETUTILS_DNSCLIENT_MAXRESPONSE
+#else
+#  define RECV_BUFFER_SIZE 96
+#endif
+
+#ifdef CONFIG_NET_IPv6
+#  define ADDRLEN sizeof(struct sockaddr_in6)
+#else
+#  define ADDRLEN sizeof(struct sockaddr_in)
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/* The DNS message header */
+
+struct dns_hdr
+{
+  uint16_t id;
+  uint8_t  flags1;
+  uint8_t  flags2;
+  uint16_t numquestions;
+  uint16_t numanswers;
+  uint16_t numauthrr;
+  uint16_t numextrarr;
+};
+
+/* The DNS answer message structure */
+
+struct dns_answer
+{
+  /* DNS answer record starts with either a domain name or a pointer
+   * to a name already present somewhere in the packet.
+   */
+
+  uint16_t type;
+  uint16_t class;
+  uint16_t ttl[2];
+  uint16_t len;
+#ifdef CONFIG_NET_IPv6
+  struct in6_addr ipaddr;
+#else
+  struct in_addr ipaddr;
+#endif
+};
+
+struct namemap
+{
+  uint8_t state;
+  uint8_t tmr;
+  uint8_t retries;
+  uint8_t seqno;
+  uint8_t err;
+  char name[32];
+#ifdef CONFIG_NET_IPv6
+  struct in6_addr ipaddr;
+#else
+  struct in_addr ipaddr;
+#endif
+};
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static uint8_t g_seqno;
+static int g_sockfd = -1;
+#ifdef CONFIG_NET_IPv6
+static struct sockaddr_in6 g_dnsserver;
+#else
+static struct sockaddr_in g_dnsserver;
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: parse_name
+ *
+ * Description:
+ *   Walk through a compact encoded DNS name and return the end of it.
+ *
+ ****************************************************************************/
+
+static FAR unsigned char *parse_name(FAR unsigned char *query)
+{
+  unsigned char n;
+
+  do
+    {
+      n = *query++;
+
+      while(n > 0)
+        {
+          ++query;
+          --n;
+        }
+    }
+  while(*query != 0);
+
+  return query + 1;
+}
+
+/****************************************************************************
+ * Name: send_query_socket
+ *
+ * Description:
+ *   Runs through the list of names to see if there are any that have
+ *   not yet been queried and, if so, sends out a query.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+static int send_query_socket(int sockfd, FAR const char *name,
+                             FAR struct sockaddr_in6 *addr)
+#else
+static int send_query_socket(int sockfd, FAR const char *name,
+                             FAR struct sockaddr_in *addr)
+#endif
+{
+  register FAR struct dns_hdr *hdr;
+  FAR char *query;
+  FAR char *nptr;
+  FAR const char *nameptr;
+  uint8_t seqno = g_seqno++;
+  static unsigned char endquery[] = {0, 0, 1, 0, 1};
+  char buffer[SEND_BUFFER_SIZE];
+  int n;
+
+  hdr               = (FAR struct dns_hdr*)buffer;
+  memset(hdr, 0, sizeof(struct dns_hdr));
+  hdr->id           = htons(seqno);
+  hdr->flags1       = DNS_FLAG1_RD;
+  hdr->numquestions = HTONS(1);
+  query             = buffer + 12;
+
+  /* Convert hostname into suitable query format. */
+
+  nameptr = name - 1;
+  do
+   {
+     nameptr++;
+     nptr = query++;
+     for (n = 0; *nameptr != '.' && *nameptr != 0; nameptr++)
+       {
+         *query++ = *nameptr;
+         n++;
+       }
+
+     *nptr = n;
+   }
+  while(*nameptr != 0);
+
+  memcpy(query, endquery, 5);
+
+#ifdef CONFIG_NET_IPv6
+  DEBUGASSERT(((struct sockaddr *)addr)->sa_family == AF_INET6);
+#else
+  DEBUGASSERT(((struct sockaddr *)addr)->sa_family == AF_INET);
+#endif
+
+  return sendto(sockfd, buffer, query + 5 - buffer,
+                0, (struct sockaddr*)addr, ADDRLEN);
+}
+
+/****************************************************************************
+ * Name: send_query
+ ****************************************************************************/
+
+#if 0 /* Not used */
+#ifdef CONFIG_NET_IPv6
+static int send_query(FAR const char *name, FAR struct sockaddr_in6 *addr)
+#else
+static int send_query(FAR const char *name, FAR struct sockaddr_in *addr)
+#endif
+{
+  return send_query_socket(g_sockfd, name, addr);
+}
+#endif
+
+/****************************************************************************
+ * Name: recv_response_socket
+ *
+ * Description:
+ *   Called when new UDP data arrives
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+#  error "Not implemented"
+#else
+int recv_response_socket(int sockfd, FAR struct sockaddr_in *addr)
+#endif
+{
+  FAR unsigned char *nameptr;
+  char buffer[RECV_BUFFER_SIZE];
+  FAR struct dns_answer *ans;
+  FAR struct dns_hdr *hdr;
+#if 0 /* Not used */
+  uint8_t nquestions;
+#endif
+  uint8_t nanswers;
+  int ret;
+
+  /* Receive the response */
+
+  ret = recv(sockfd, buffer, RECV_BUFFER_SIZE, 0);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  hdr = (FAR struct dns_hdr *)buffer;
+
+  ndbg("ID %d\n", htons(hdr->id));
+  ndbg("Query %d\n", hdr->flags1 & DNS_FLAG1_RESPONSE);
+  ndbg("Error %d\n", hdr->flags2 & DNS_FLAG2_ERR_MASK);
+  ndbg("Num questions %d, answers %d, authrr %d, extrarr %d\n",
+       htons(hdr->numquestions), htons(hdr->numanswers),
+       htons(hdr->numauthrr), htons(hdr->numextrarr));
+
+  /* Check for error. If so, call callback to inform */
+
+  if ((hdr->flags2 & DNS_FLAG2_ERR_MASK) != 0)
+    {
+      return ERROR;
+    }
+
+  /* We only care about the question(s) and the answers. The authrr
+   * and the extrarr are simply discarded.
+   */
+
+#if 0 /* Not used */
+  nquestions = htons(hdr->numquestions);
+#endif
+  nanswers   = htons(hdr->numanswers);
+
+  /* Skip the name in the question. TODO: This should really be
+   * checked against the name in the question, to be sure that they
+   * match.
+   */
+
+#ifdef CONFIG_DEBUG_NET
+  {
+    int d = 64;
+    nameptr = parse_name((unsigned char *)buffer + 12) + 4;
+
+    for (;;)
+      {
+        ndbg("%02X %02X %02X %02X %02X %02X %02X %02X \n",
+             nameptr[0],nameptr[1],nameptr[2],nameptr[3],
+             nameptr[4],nameptr[5],nameptr[6],nameptr[7]);
+
+        nameptr += 8;
+        d -= 8;
+        if (d < 0)
+          {
+            break;
+          }
+      }
+  }
+#endif
+
+  nameptr = parse_name((unsigned char *)buffer + 12) + 4;
+
+  for (; nanswers > 0; nanswers--)
+    {
+      /* The first byte in the answer resource record determines if it
+       * is a compressed record or a normal one.
+       */
+
+      if (*nameptr & 0xc0)
+        {
+          /* Compressed name. */
+
+          nameptr += 2;
+          ndbg("Compressed answer\n");
+        }
+      else
+        {
+          /* Not compressed name. */
+
+          nameptr = parse_name(nameptr);
+        }
+
+      ans = (struct dns_answer *)nameptr;
+      ndbg("Answer: type %x, class %x, ttl %x, length %x \n", /* 0x%08X\n", */
+           htons(ans->type), htons(ans->class),
+           (htons(ans->ttl[0]) << 16) | htons(ans->ttl[1]),
+           htons(ans->len) /* , ans->ipaddr.s_addr */);
+
+      /* Check for IP address type and Internet class. Others are discarded. */
+
+      if (ans->type  == HTONS(1) &&
+          ans->class == HTONS(1) &&
+          ans->len   == HTONS(4))
+        {
+          ans->ipaddr.s_addr = *(FAR uint32_t *)(nameptr + 10);
+
+          ndbg("IP address %d.%d.%d.%d\n",
+               (ans->ipaddr.s_addr       ) & 0xff,
+               (ans->ipaddr.s_addr >> 8  ) & 0xff,
+               (ans->ipaddr.s_addr >> 16 ) & 0xff,
+               (ans->ipaddr.s_addr >> 24 ) & 0xff);
+
+          /* TODO: we should really check that this IP address is the one
+           * we want.
+           */
+
+          addr->sin_addr.s_addr = ans->ipaddr.s_addr;
+          return OK;
+        }
+      else
+        {
+          nameptr = nameptr + 10 + htons(ans->len);
+        }
+    }
+
+  return ERROR;
+}
+
+/****************************************************************************
+ * Name: recv_response
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+#  error "Not implemented"
+#else
+int recv_response(FAR struct sockaddr_in *addr)
+#endif
+{
+  return recv_response_socket(g_sockfd, addr);
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: dns_bind_sock
+ *
+ * Description:
+ *   Initialize the DNS resolver using the caller provided socket.
+ *
+ ****************************************************************************/
+
+int dns_bind_sock(FAR int *sockfd)
+{
+  struct timeval tv;
+  int ret;
+
+  if (*sockfd >= 0) dns_free_sock(sockfd);
+
+  *sockfd = socket(PF_INET, SOCK_DGRAM, 0);
+  if (*sockfd < 0)
+    {
+      return ERROR;
+    }
+
+  /* Set up a receive timeout */
+
+  tv.tv_sec  = 30;
+  tv.tv_usec = 0;
+
+  ret = setsockopt(*sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv,
+                   sizeof(struct timeval));
+
+  if (ret < 0)
+    {
+      close(*sockfd);
+      *sockfd = -1;
+      return ERROR;
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * 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_free_sock
+ *
+ * Description:
+ *   Release the DNS resolver by closing the socket.
+ *
+ ****************************************************************************/
+
+int dns_free_sock(FAR int *sockfd)
+{
+  if (*sockfd >= 0)
+    {
+      close(*sockfd);
+      *sockfd = -1;
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: dns_query_sock
+ *
+ * Description:
+ *   Using the DNS resolver socket (sockfd), 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_sock(int sockfd, FAR const char *hostname, FAR in_addr_t *ipaddr)
+{
+#ifdef CONFIG_HAVE_GETHOSTBYNAME
+
+  FAR struct hostent *he;
+
+  nvdbg("Getting address of %s\n", hostname);
+  he = gethostbyname(hostname);
+  if (!he)
+    {
+      ndbg("gethostbyname failed: %d\n", h_errno);
+      return ERROR;
+    }
+
+  nvdbg("Using IP address %04x%04x\n",
+       (uint16_t)he->h_addr[1], (uint16_t)he->h_addr[0]);
+
+  memcpy(ipaddr, he->h_addr, sizeof(in_addr_t));
+  return OK;
+
+#else
+
+# ifdef CONFIG_NET_IPv6
+  struct sockaddr_in6 addr;
+# else
+  struct sockaddr_in addr;
+# endif
+
+  /* First check if the host is an IP address. */
+
+  if (!uiplib_ipaddrconv(hostname, (uint8_t*)ipaddr))
+    {
+      /* 'host' does not point to a valid address string.  Try to resolve
+       *  the host name to an IP address.
+       */
+
+      if (dns_whois_socket(sockfd, hostname, &addr) < 0)
+        {
+          /* Needs to set the errno here */
+
+          return ERROR;
+        }
+
+      /* Save the host address -- Needs fixed for IPv6 */
+
+      *ipaddr = addr.sin_addr.s_addr;
+  }
+
+  return OK;
+#endif
+}
+
+/****************************************************************************
+ * 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_setserver
+ *
+ * Description:
+ *   Configure which DNS server to use for queries
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+void dns_setserver(FAR const struct in6_addr *dnsserver)
+#else
+void dns_setserver(FAR const struct in_addr *dnsserver)
+#endif
+{
+  g_dnsserver.sin_family = AF_INET;
+  g_dnsserver.sin_port   = HTONS(53);
+#ifdef CONFIG_NET_IPv6
+  memcpy(&g_dnsserver.sin6_addr, dnsserver, ADDRLEN);
+#else
+  g_dnsserver.sin_addr.s_addr = dnsserver->s_addr;
+#endif
+}
+
+/****************************************************************************
+ * Name: dns_getserver
+ *
+ * Description:
+ *   Obtain the currently configured DNS server.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+void dns_getserver(FAR struct in6_addr *dnsserver)
+#else
+void dns_getserver(FAR struct in_addr *dnsserver)
+#endif
+{
+#ifdef CONFIG_NET_IPv6
+  memcpy(dnsserver, &g_dnsserver.sin6_addr, ADDRLEN);
+#else
+  dnsserver->s_addr = g_dnsserver.sin_addr.s_addr;
+#endif
+}
+
+/****************************************************************************
+ * Name: dns_whois_socket
+ *
+ * Description:
+ *   Get the binding for 'name' using the DNS server accessed via 'sockfd'
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+int dns_whois_socket(int sockfd, FAR const char *name,
+                     FAR struct sockaddr_in6 *addr)
+#else
+int dns_whois_socket(int sockfd, FAR const char *name,
+                     FAR struct sockaddr_in *addr)
+#endif
+{
+  int retries;
+  int ret;
+
+  /* Loop while receive timeout errors occur and there are remaining retries */
+
+  for (retries = 0; retries < 3; retries++)
+    {
+      if (send_query_socket(sockfd, name, &g_dnsserver) < 0)
+        {
+          return ERROR;
+        }
+
+      ret = recv_response_socket(sockfd, addr);
+      if (ret >= 0)
+        {
+          /* Response received successfully */
+
+          return OK;
+        }
+
+      else if (errno != EAGAIN)
+        {
+          /* Some failure other than receive timeout occurred */
+
+          return ERROR;
+        }
+    }
+
+  return ERROR;
+}
+
+/****************************************************************************
+ * Name: dns_whois
+ *
+ * Description:
+ *   Get the binding for 'name' using the DNS server accessed via the DNS
+ *   resolvers internal socket.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_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);
+}
+
+/****************************************************************************
+ * Name: dns_gethostip
+ *
+ * Descriptions:
+ *   Combines the operations of dns_bind_sock(), dns_query_sock(), and
+ *   dns_free_sock() to obtain the the IP address ('ipaddr') associated with
+ *   the 'hostname' in one operation.
+ *
+ ****************************************************************************/
+
+int dns_gethostip(FAR const char *hostname, FAR in_addr_t *ipaddr)
+{
+  int sockfd = -1;
+  int ret=ERROR;
+
+  dns_bind_sock(&sockfd);
+  if (sockfd >= 0)
+    {
+      ret = dns_query_sock(sockfd, hostname, ipaddr);
+      dns_free_sock(&sockfd);
+    }
+
+  return ret;
+}
+