3 Copyright (C) Dean Camera, 2014.
5 dean [at] fourwalledcubicle [dot] com
10 Copyright 2014 Dean Camera (dean [at] fourwalledcubicle [dot] com)
12 Permission to use, copy, modify, distribute, and sell this
13 software and its documentation for any purpose is hereby granted
14 without fee, provided that the above copyright notice appear in
15 all copies and that both that the copyright notice and this
16 permission notice and warranty disclaimer appear in supporting
17 documentation, and that the name of the author not be used in
18 advertising or publicity pertaining to distribution of the
19 software without specific, written prior permission.
21 The author disclaims all warranties with regard to this
22 software, including all implied warranties of merchantability
23 and fitness. In no event shall the author be liable for any
24 special, indirect or consequential damages or any damages
25 whatsoever resulting from loss of use, data or profits, whether
26 in an action of contract, negligence or other tortious action,
27 arising out of or in connection with the use or performance of
33 * Internet Control Message Protocol (ICMP) packet handling routines. This protocol handles
34 * Echo requests from the host, to indicate a successful network connection between the host
35 * and the virtual server.
40 /** Processes an ICMP packet inside an Ethernet frame, and writes the appropriate response
41 * to the output Ethernet frame if the host is issuing a ICMP ECHO request.
43 * \param[in] FrameIN Pointer to the incoming Ethernet frame information structure
44 * \param[in] InDataStart Pointer to the start of the incoming packet's ICMP header
45 * \param[out] OutDataStart Pointer to the start of the outgoing packet's ICMP header
47 * \return The number of bytes written to the out Ethernet frame if any, NO_RESPONSE otherwise
49 int16_t ICMP_ProcessICMPPacket(Ethernet_Frame_Info_t* const FrameIN,
53 ICMP_Header_t* ICMPHeaderIN = (ICMP_Header_t*)InDataStart;
54 ICMP_Header_t* ICMPHeaderOUT = (ICMP_Header_t*)OutDataStart;
56 DecodeICMPHeader(InDataStart);
58 /* Determine if the ICMP packet is an echo request (ping) */
59 if (ICMPHeaderIN->Type == ICMP_TYPE_ECHOREQUEST)
61 /* Fill out the ICMP response packet */
62 ICMPHeaderOUT->Type = ICMP_TYPE_ECHOREPLY;
63 ICMPHeaderOUT->Code = 0;
64 ICMPHeaderOUT->Checksum = 0;
65 ICMPHeaderOUT->Id = ICMPHeaderIN->Id;
66 ICMPHeaderOUT->Sequence = ICMPHeaderIN->Sequence;
68 intptr_t DataSize = FrameIN->FrameLength - ((((intptr_t)InDataStart + sizeof(ICMP_Header_t)) - (intptr_t)FrameIN->FrameData));
70 /* Copy the remaining payload to the response - echo requests should echo back any sent data */
71 memmove(&((uint8_t*)OutDataStart)[sizeof(ICMP_Header_t)],
72 &((uint8_t*)InDataStart)[sizeof(ICMP_Header_t)],
75 ICMPHeaderOUT->Checksum = Ethernet_Checksum16(ICMPHeaderOUT, (DataSize + sizeof(ICMP_Header_t)));
77 /* Return the size of the response so far */
78 return (DataSize + sizeof(ICMP_Header_t));