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- /*
- LUFA Library
- Copyright (C) Dean Camera, 2014.
-
- dean [at] fourwalledcubicle [dot] com
- www.lufa-lib.org
- */
-
- /*
- Copyright 2014 Dean Camera (dean [at] fourwalledcubicle [dot] com)
-
- Permission to use, copy, modify, distribute, and sell this
- software and its documentation for any purpose is hereby granted
- without fee, provided that the above copyright notice appear in
- all copies and that both that the copyright notice and this
- permission notice and warranty disclaimer appear in supporting
- documentation, and that the name of the author not be used in
- advertising or publicity pertaining to distribution of the
- software without specific, written prior permission.
-
- The author disclaims all warranties with regard to this
- software, including all implied warranties of merchantability
- and fitness. In no event shall the author be liable for any
- special, indirect or consequential damages or any damages
- whatsoever resulting from loss of use, data or profits, whether
- in an action of contract, negligence or other tortious action,
- arising out of or in connection with the use or performance of
- this software.
- */
-
- /** \file
- *
- * Ethernet frame packet handling routines. This protocol handles the processing of raw Ethernet
- * frames sent and received, deferring the processing of sub-packet protocols to the appropriate
- * protocol handlers, such as DHCP or ARP.
- */
-
- #include "Ethernet.h"
-
- /** Constant for convenience when checking against or setting a MAC address to the virtual server MAC address. */
- const MAC_Address_t ServerMACAddress = {SERVER_MAC_ADDRESS};
-
- /** Constant for convenience when checking against or setting an IP address to the virtual server IP address. */
- const IP_Address_t ServerIPAddress = {SERVER_IP_ADDRESS};
-
- /** Constant for convenience when checking against or setting a MAC address to the broadcast MAC address. */
- const MAC_Address_t BroadcastMACAddress = {BROADCAST_MAC_ADDRESS};
-
- /** Constant for convenience when checking against or setting a IP address to the broadcast IP address. */
- const IP_Address_t BroadcastIPAddress = {BROADCAST_IP_ADDRESS};
-
- /** Constant for convenience when checking against or setting an IP address to the client (host) IP address. */
- const IP_Address_t ClientIPAddress = {CLIENT_IP_ADDRESS};
-
-
- /** Processes an incoming Ethernet frame, and writes the appropriate response to the output Ethernet
- * frame buffer if the sub protocol handlers create a valid response.
- */
- void Ethernet_ProcessPacket(Ethernet_Frame_Info_t* const FrameIN,
- Ethernet_Frame_Info_t* const FrameOUT)
- {
- DecodeEthernetFrameHeader(FrameIN->FrameData);
-
- /* Cast the incoming Ethernet frame to the Ethernet header type */
- Ethernet_Frame_Header_t* FrameINHeader = (Ethernet_Frame_Header_t*)&FrameIN->FrameData;
- Ethernet_Frame_Header_t* FrameOUTHeader = (Ethernet_Frame_Header_t*)&FrameOUT->FrameData;
-
- int16_t RetSize = NO_RESPONSE;
-
- /* Ensure frame is addressed to either all (broadcast) or the virtual webserver, and is a type II frame */
- if ((MAC_COMPARE(&FrameINHeader->Destination, &ServerMACAddress) ||
- MAC_COMPARE(&FrameINHeader->Destination, &BroadcastMACAddress)) &&
- (SwapEndian_16(FrameIN->FrameLength) > ETHERNET_VER2_MINSIZE))
- {
- /* Process the packet depending on its protocol */
- switch (SwapEndian_16(FrameINHeader->EtherType))
- {
- case ETHERTYPE_ARP:
- RetSize = ARP_ProcessARPPacket(&FrameIN->FrameData[sizeof(Ethernet_Frame_Header_t)],
- &FrameOUT->FrameData[sizeof(Ethernet_Frame_Header_t)]);
- break;
- case ETHERTYPE_IPV4:
- RetSize = IP_ProcessIPPacket(FrameIN,
- &FrameIN->FrameData[sizeof(Ethernet_Frame_Header_t)],
- &FrameOUT->FrameData[sizeof(Ethernet_Frame_Header_t)]);
- break;
- }
-
- /* Protocol processing routine has filled a response, complete the ethernet frame header */
- if (RetSize > 0)
- {
- /* Fill out the response Ethernet frame header */
- FrameOUTHeader->Source = ServerMACAddress;
- FrameOUTHeader->Destination = FrameINHeader->Source;
- FrameOUTHeader->EtherType = FrameINHeader->EtherType;
-
- /* Set the response length in the buffer and indicate that a response is ready to be sent */
- FrameOUT->FrameLength = (sizeof(Ethernet_Frame_Header_t) + RetSize);
- }
- }
-
- /* Check if the packet was processed */
- if (RetSize != NO_PROCESS)
- {
- /* Clear the frame buffer */
- FrameIN->FrameLength = 0;
- }
- }
-
- /** Calculates the appropriate ethernet checksum, consisting of the addition of the one's
- * compliment of each word, complimented.
- *
- * \param[in] Data Pointer to the packet buffer data whose checksum must be calculated
- * \param[in] Bytes Number of bytes in the data buffer to process
- *
- * \return A 16-bit Ethernet checksum value
- */
- uint16_t Ethernet_Checksum16(void* Data,
- uint16_t Bytes)
- {
- uint16_t* Words = (uint16_t*)Data;
- uint32_t Checksum = 0;
-
- for (uint16_t CurrWord = 0; CurrWord < (Bytes >> 1); CurrWord++)
- Checksum += Words[CurrWord];
-
- while (Checksum & 0xFFFF0000)
- Checksum = ((Checksum & 0xFFFF) + (Checksum >> 16));
-
- return ~Checksum;
- }
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