/*********************************************************************
*
* Domain Name System (DNS) Server dummy
* Module for Microchip TCP/IP Stack
* -Acts as a DNS server, but gives out the local IP address for all
* queries to force web browsers to access the board.
* -Reference: RFC 1034 and RFC 1035
*
*********************************************************************
* FileName: DNSs.c
* Dependencies: UDP
* Processor: PIC18, PIC24F, PIC24H, dsPIC30F, dsPIC33F, PIC32
* Compiler: Microchip C32 v1.05 or higher
* Microchip C30 v3.12 or higher
* Microchip C18 v3.30 or higher
* Company: Microchip Technology, Inc.
*
* Software License Agreement
*
* Copyright (C) 2002-2010 Microchip Technology Inc. All rights
* reserved.
*
* Microchip licenses to you the right to use, modify, copy, and
* distribute:
* (i) the Software when embedded on a Microchip microcontroller or
* digital signal controller product ("Device") which is
* integrated into Licensee's product; or
* (ii) ONLY the Software driver source files ENC28J60.c, ENC28J60.h,
* ENCX24J600.c and ENCX24J600.h ported to a non-Microchip device
* used in conjunction with a Microchip ethernet controller for
* the sole purpose of interfacing with the ethernet controller.
*
* You should refer to the license agreement accompanying this
* Software for additional information regarding your rights and
* obligations.
*
* THE SOFTWARE AND DOCUMENTATION ARE PROVIDED "AS IS" WITHOUT
* WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT
* LIMITATION, ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* MICROCHIP BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA, COST OF
* PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES, ANY CLAIMS
* BY THIRD PARTIES (INCLUDING BUT NOT LIMITED TO ANY DEFENSE
* THEREOF), ANY CLAIMS FOR INDEMNITY OR CONTRIBUTION, OR OTHER
* SIMILAR COSTS, WHETHER ASSERTED ON THE BASIS OF CONTRACT, TORT
* (INCLUDING NEGLIGENCE), BREACH OF WARRANTY, OR OTHERWISE.
*
*
* Author Date Comment
*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Howard Schlunder 01/18/2010 Original
********************************************************************/
#define DNSS_C
#include "TCPIPConfig.h"
#if defined(STACK_USE_DNS_SERVER)
#include "TCPIP Stack/TCPIP.h"
// Default port for the DNS server to listen on
#define DNS_PORT 53u
static void DNSCopyRXNameToTX(void);
/*********************************************************************
* Function: void DNSServerTask(void)
*
* PreCondition: None
*
* Input: None
*
* Output: None
*
* Side Effects: None
*
* Overview: Sends dummy responses that point to ourself for DNS requests
*
* Note: None
********************************************************************/
void DNSServerTask(void)
{
static UDP_SOCKET MySocket = INVALID_UDP_SOCKET;
struct
{
WORD wTransactionID;
WORD wFlags;
WORD wQuestions;
WORD wAnswerRRs;
WORD wAuthorityRRs;
WORD wAdditionalRRs;
} DNSHeader;
// Create a socket to listen on if this is the first time calling this function
if(MySocket == INVALID_UDP_SOCKET)
{
MySocket = UDPOpen(DNS_PORT, NULL, 0);
return;
}
// See if a DNS query packet has arrived
if(UDPIsGetReady(MySocket) < sizeof(DNSHeader))
return;
// Read DNS header
UDPGetArray((BYTE*)&DNSHeader, sizeof(DNSHeader));
// Ignore this packet if it isn't a query
if((DNSHeader.wFlags & 0x8000) == 0x8000u)
return;
// Ignore this packet if there are no questions in it
if(DNSHeader.wQuestions == 0u)
return;
// Block until we can transmit a DNS response packet
while(!UDPIsPutReady(MySocket));
// Write DNS response packet
UDPPutArray((BYTE*)&DNSHeader.wTransactionID, 2); // 2 byte Transaction ID
if(DNSHeader.wFlags & 0x0100)
UDPPut(0x81); // Message is a response with recursion desired
else
UDPPut(0x80); // Message is a response without recursion desired flag set
UDPPut(0x80); // Recursion available
UDPPut(0x00); // 0x0000 Questions
UDPPut(0x00);
UDPPut(0x00); // 0x0001 Answers RRs
UDPPut(0x01);
UDPPut(0x00); // 0x0000 Authority RRs
UDPPut(0x00);
UDPPut(0x00); // 0x0000 Additional RRs
UDPPut(0x00);
DNSCopyRXNameToTX(); // Copy hostname of first question over to TX packet
UDPPut(0x00); // Type A Host address
UDPPut(0x01);
UDPPut(0x00); // Class INternet
UDPPut(0x01);
UDPPut(0x00); // Time to Live 10 seconds
UDPPut(0x00);
UDPPut(0x00);
UDPPut(0x0A);
UDPPut(0x00); // Data Length 4 bytes
UDPPut(0x04);
UDPPutArray((BYTE*)&AppConfig.MyIPAddr.Val, 4); // Our IP address
UDPFlush();
}
/*****************************************************************************
Function:
static void DNSCopyRXNameToTX(void)
Summary:
Copies a DNS hostname, possibly including name compression, from the RX
packet to the TX packet (without name compression in TX case).
Description:
None
Precondition:
RX pointer is set to currently point to the DNS name to copy
Parameters:
None
Returns:
None
***************************************************************************/
static void DNSCopyRXNameToTX(void)
{
WORD w;
BYTE i;
BYTE len;
while(1)
{
// Get first byte which will tell us if this is a 16-bit pointer or the
// length of the first of a series of labels
if(!UDPGet(&i))
return;
// Check if this is a pointer, if so, get the reminaing 8 bits and seek to the pointer value
if((i & 0xC0u) == 0xC0u)
{
((BYTE*)&w)[1] = i & 0x3F;
UDPGet((BYTE*)&w);
IPSetRxBuffer(sizeof(UDP_HEADER) + w);
continue;
}
// Write the length byte
len = i;
UDPPut(len);
// Exit if we've reached a zero length label
if(len == 0u)
return;
// Copy all of the bytes in this label
while(len--)
{
UDPGet(&i);
UDPPut(i);
}
}
}
#endif //#if defined(STACK_USE_DNS_SERVER)
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