nadnsclnt: DNS Client Test Application

This example application demonstrates the DNS client API.
This example should work on all development boards.
It does the following:

1.  The development board is initialized and the POST tests
    are executed.
2.  The ThreadX kernel is loaded.
3.  The device drivers are loaded.
4.  The TCP/IP stack is loaded.
5.  The function applicationStart() is called.
6.  In function applicationStart(), added a DNS server to the system.
7.  Tests the DNSAddServer(), DNSGetServers(), and DNSRemoveServer()
    functions.
8.  Uses DNSgethostbyname() to get the host's IP address by name.
9   Uses gethostbyaddr() function to get host name by IP address.
    This function returns the pointer to struct hostent, with the host
	name pointed to by h_name field.

The standard getaddrinfo() and getnameinfo() functions are used to resolve
addresses and names. 

NOTE: In order to test both IPv6 and IPv4 DNS define TEST_IPV6_DNS in root.c. 
      If TEST_IPV6_DNS is undefined, only IPv4 DNS is tested.

The application prints all results by means of printf().

The DNS server name and the host name are hard coded in the
following local variables:
  server
  server1
  name1
  name2
 

One GNU make file is provided.  Build the target 'image' to
generate an image that can be debugged with gdb, and the file 
image.bin which can be written to flash if the bootloader is used.
Build the target 'rom.bin' to create the file rom.bin which 
can be written to ROM if the bootloader is not used.

The following files are provided in this example.

appconf.h         sets application configuration settings
makefile          Make file for the GNU toolset.
readme            this file
root.c            contains applicationStart() function



In addition, the following files in the BSP directory are built
as part of this application.

reset.s         contains the reset code
appconf_api.c   contains code used to read settings in appconf.h


The application build file links in the following libraries.

libbsp.a               contains the BSP library
libaddp.a			   contains the ADDP Library
libtcpip.a             contains the TCP/IP stack library
libpppintf.a		   contains the PPP Interface Library
libtx.a                contains the ThreadX kernel
libfilesys.a           contains the Native File System library
libposix.a             contains the POSIX layer library
libflash.a             contains the Flash driver API library
libssh.a			   contains the SSH Library
libtelnsvr.a           contains the Telnet Server library
libdnsclnt.a           contains the DNS Client library

The application uses the following files located in the
netos\src\linkerScripts directory.

bootldr.dat     bootloader configuration file used to generate the
                file image.bin.  It controls the information placed
                in the bootloader header of the image.

image.ldr       GNU linker script used to build an image that can
                be debugged and used with the bootloader.
                
customize.ldr   Customizable GNU linker script
