114 lines
4.4 KiB
C
114 lines
4.4 KiB
C
/*
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LUFA Library
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Copyright (C) Dean Camera, 2017.
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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 2017 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 Protocol (IP) packet handling routines. This protocol handles IP packets from the
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* host which typically encapsulate other protocols such as ICMP, UDP and TCP.
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*/
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#include "IP.h"
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/** Processes an IP packet inside an Ethernet frame, and writes the appropriate response
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* to the output Ethernet frame if one is created by a sub-protocol handler.
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*
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* \param[in] InDataStart Pointer to the start of the incoming packet's IP header
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* \param[out] OutDataStart Pointer to the start of the outgoing packet's IP header
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*
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* \return The number of bytes written to the out Ethernet frame if any, NO_RESPONSE if no
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* response was generated, NO_PROCESS if the packet processing was deferred until the
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* next Ethernet packet handler iteration
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*/
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int16_t IP_ProcessIPPacket(void* InDataStart,
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void* OutDataStart)
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{
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DecodeIPHeader(InDataStart);
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IP_Header_t* IPHeaderIN = (IP_Header_t*)InDataStart;
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IP_Header_t* IPHeaderOUT = (IP_Header_t*)OutDataStart;
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/* Header length is specified in number of longs in the packet header, convert to bytes */
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uint16_t HeaderLengthBytes = (IPHeaderIN->HeaderLength * sizeof(uint32_t));
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int16_t RetSize = NO_RESPONSE;
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/* Check to ensure the IP packet is addressed to the virtual webserver's IP or the broadcast IP address */
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if (!(IP_COMPARE(&IPHeaderIN->DestinationAddress, &ServerIPAddress)) &&
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!(IP_COMPARE(&IPHeaderIN->DestinationAddress, &BroadcastIPAddress)))
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{
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return NO_RESPONSE;
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}
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/* Pass off the IP payload to the appropriate protocol processing routine */
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switch (IPHeaderIN->Protocol)
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{
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case PROTOCOL_ICMP:
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RetSize = ICMP_ProcessICMPPacket(&((uint8_t*)InDataStart)[HeaderLengthBytes],
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&((uint8_t*)OutDataStart)[sizeof(IP_Header_t)]);
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break;
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case PROTOCOL_TCP:
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RetSize = TCP_ProcessTCPPacket(InDataStart,
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&((uint8_t*)InDataStart)[HeaderLengthBytes],
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&((uint8_t*)OutDataStart)[sizeof(IP_Header_t)]);
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break;
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case PROTOCOL_UDP:
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RetSize = UDP_ProcessUDPPacket(InDataStart,
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&((uint8_t*)InDataStart)[HeaderLengthBytes],
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&((uint8_t*)OutDataStart)[sizeof(IP_Header_t)]);
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break;
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}
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/* Check to see if the protocol processing routine has filled out a response */
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if (RetSize > 0)
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{
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/* Fill out the response IP packet header */
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IPHeaderOUT->TotalLength = SwapEndian_16(sizeof(IP_Header_t) + RetSize);
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IPHeaderOUT->TypeOfService = 0;
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IPHeaderOUT->HeaderLength = (sizeof(IP_Header_t) / sizeof(uint32_t));
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IPHeaderOUT->Version = 4;
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IPHeaderOUT->Flags = 0;
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IPHeaderOUT->FragmentOffset = 0;
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IPHeaderOUT->Identification = 0;
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IPHeaderOUT->HeaderChecksum = 0;
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IPHeaderOUT->Protocol = IPHeaderIN->Protocol;
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IPHeaderOUT->TTL = DEFAULT_TTL;
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IPHeaderOUT->SourceAddress = IPHeaderIN->DestinationAddress;
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IPHeaderOUT->DestinationAddress = IPHeaderIN->SourceAddress;
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IPHeaderOUT->HeaderChecksum = Ethernet_Checksum16(IPHeaderOUT, sizeof(IP_Header_t));
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/* Return the size of the response so far */
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return (sizeof(IP_Header_t) + RetSize);
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}
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return RetSize;
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}
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