82 lines
3.0 KiB
C
82 lines
3.0 KiB
C
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/*
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LUFA Library
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Copyright (C) Dean Camera, 2019.
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dean [at] fourwalledcubicle [dot] com
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www.lufa-lib.org
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*/
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/*
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Copyright 2019 Dean Camera (dean [at] fourwalledcubicle [dot] com)
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Permission to use, copy, modify, distribute, and sell this
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software and its documentation for any purpose is hereby granted
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without fee, provided that the above copyright notice appear in
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all copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of the author not be used in
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advertising or publicity pertaining to distribution of the
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software without specific, written prior permission.
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The author disclaims all warranties with regard to this
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software, including all implied warranties of merchantability
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and fitness. In no event shall the author be liable for any
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special, indirect or consequential damages or any damages
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whatsoever resulting from loss of use, data or profits, whether
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in an action of contract, negligence or other tortious action,
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arising out of or in connection with the use or performance of
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this software.
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*/
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/** \file
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*
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* Internet Control Message Protocol (ICMP) packet handling routines. This protocol handles
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* Echo requests from the host, to indicate a successful network connection between the host
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* and the virtual server.
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*/
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#include "ICMP.h"
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/** Processes an ICMP packet inside an Ethernet frame, and writes the appropriate response
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* to the output Ethernet frame if the host is issuing a ICMP ECHO request.
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*
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* \param[in] InDataStart Pointer to the start of the incoming packet's ICMP header
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* \param[out] OutDataStart Pointer to the start of the outgoing packet's ICMP header
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*
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* \return The number of bytes written to the out Ethernet frame if any, NO_RESPONSE otherwise
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*/
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int16_t ICMP_ProcessICMPPacket(void* InDataStart,
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void* OutDataStart)
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{
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ICMP_Header_t* ICMPHeaderIN = (ICMP_Header_t*)InDataStart;
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ICMP_Header_t* ICMPHeaderOUT = (ICMP_Header_t*)OutDataStart;
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DecodeICMPHeader(InDataStart);
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/* Determine if the ICMP packet is an echo request (ping) */
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if (ICMPHeaderIN->Type == ICMP_TYPE_ECHOREQUEST)
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{
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/* Fill out the ICMP response packet */
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ICMPHeaderOUT->Type = ICMP_TYPE_ECHOREPLY;
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ICMPHeaderOUT->Code = 0;
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ICMPHeaderOUT->Checksum = 0;
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ICMPHeaderOUT->Id = ICMPHeaderIN->Id;
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ICMPHeaderOUT->Sequence = ICMPHeaderIN->Sequence;
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intptr_t DataSize = FrameIN.FrameLength - ((((intptr_t)InDataStart + sizeof(ICMP_Header_t)) - (intptr_t)FrameIN.FrameData));
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/* Copy the remaining payload to the response - echo requests should echo back any sent data */
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memmove(&((uint8_t*)OutDataStart)[sizeof(ICMP_Header_t)],
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&((uint8_t*)InDataStart)[sizeof(ICMP_Header_t)],
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DataSize);
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ICMPHeaderOUT->Checksum = Ethernet_Checksum16(ICMPHeaderOUT, (DataSize + sizeof(ICMP_Header_t)));
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/* Return the size of the response so far */
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return (DataSize + sizeof(ICMP_Header_t));
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}
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return NO_RESPONSE;
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}
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