Unit ICMP

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Description

Ultibo ICMP (Internet Control Message Protocol) unit

Constants


ICMP protocol ICMP_PROTOCOL_*
Note: Some ICMP definitions are in the Protocol or IP modules
 
ICMP_PROTOCOL_NAME = 'ICMP';  


ICMP specific constants ICMP_*
ICMP_TIMEOUT = 0; Wait forever on a ICMP Read
ICMP_BUFFER_SIZE = 65536; ICMP Receive Buffer Size
 
ICMP_HEADER_SIZE = 8; SizeOf(TICMPHeader); ICMP.Solicit
 
ICMP_PACKET_SIZE = 8; SizeOf(TICMPPacket)
 
ICMP_ROUTER_TIMEOUT = 60000;  


Type definitions


ICMP unused header

PICMPUnusedHeader = ^TICMPUnusedHeader;

TICMPUnusedHeader = packed record {Unreachable, TimeExceeded, SourceQuench etc}

Note: Some ICMP definitions are in the Protocol or IP modules
ICMPType:Byte; ICMP_UNREACH etc
Code:Byte; ICMP_UNREACH_NET,ICMP_UNREACH_PORT etc
Checksum:Word; 1s Compliment checksum of Structure
Unused:LongWord; 4 Bytes Unused Must be Zero
IP:TIPHeader; IP Header from Original IP Packet
Data:array[0..7] of Byte; 8 Bytes of Original IP Packet Data

ICMP unreach header

PICMPUnreachHeader = ^TICMPUnreachHeader;

TICMPUnreachHeader = TICMPUnusedHeader;

Note: ICMP_UNREACH
   

ICMP expire header

PICMPExpireHeader = ^TICMPExpireHeader;

TICMPExpireHeader = TICMPUnusedHeader;

Note: ICMP_TIMXCEED
   

ICMP quench header

PICMPQuenchHeader = ^TICMPQuenchHeader;

TICMPQuenchHeader = TICMPUnusedHeader;

Note: ICMP_SOURCEQUENCH
   

ICMP pointer header

PICMPPointerHeader = ^TICMPPointerHeader;

TICMPPointerHeader = packed record

Note: Param Problem
ICMPType:Byte; ICMP_PARAMPROB etc
Code:Byte; ICMP_PARAMPROB_OPTABSENT etc
Checksum:Word; 1s Compliment checksum of Structure
Pointer:Byte; If Code = 0 Pointer to Byte where Error Occured
Unused:array[0..2] of Byte; 3 Bytes Unused Must be Zero
IP:TIPHeader; IP Header from Original IP Packet
Data:array[0..7] of Byte; 8 Bytes of Original IP Packet Data

ICMP param header

PICMPParamHeader = ^TICMPParamHeader;

TICMPParamHeader = TICMPPointerHeader;

Note: ICMP_PARAMPROB
   

ICMP IP header

PICMPIpHeader = ^TICMPIpHeader;

TICMPIpHeader = packed record

Note: Redirect
ICMPType:Byte; ICMP_REDIRECT etc
Code:Byte; ICMP_REDIRECT_NET,ICMP_REDIRECT_HOST etc
Checksum:Word; 1s Compliment checksum of Structure
Gateway:TInAddr; Redirect Gateway Address
IP:TIPHeader; IP Header from Original IP Packet
Data:array[0..7] of Byte; 8 Bytes of Original IP Packet Data

ICMP redirect header

PICMPRedirectHeader = ^TICMPRedirectHeader;

TICMPRedirectHeader = TICMPIpHeader

Note: ICMP_REDIRECT
   

ICMP echo header

PICMPEchoHeader = ^TICMPEchoHeader;

TICMPEchoHeader = packed record

Note: Echo Request/Reply
ICMPType:Byte; ICMP_ECHO,ICMP_ECHOREPLY
Code:Byte; Always 0
Checksum:Word; 1s Compliment checksum of Structure
Identifier:Word; Increments with each ICMP_ECHO
Sequence:Word; Sequence within an ICMP_ECHO set
Data:array[0..((MAX_IP_PACKET - 1) - SizeOf(TIPHeader)) - 8] of Byte;  

ICMP time stamp header

PICMPTimestampHeader = ^TICMPTimestampHeader;

TICMPTimestampHeader = packed record

Note: Timestamp Request/Reply
ICMPType:Byte; ICMP_TSTAMP,ICMP_TSTAMPREPLY
Code:Byte; Always 0
Checksum:Word; 1s Compliment checksum of Structure
Identifier:Word; Increments with each ICMP_TSTAMP
Sequence:Word; Sequence within an ICMP_TSTAMP set
Original:LongWord; Original Timestamp
Receive:LongWord; Receive Timestamp
Transmit:LongWord; Transmit Timestamp (A sort of Round Trip Time Echo)

ICMP info header

PICMPInfoHeader = ^TICMPInfoHeader;

TICMPInfoHeader = packed record

Note: Info Request/Reply
ICMPType:Byte; ICMP_IREQ,ICMP_IREQREPLY
Code:Byte; Always 0
Checksum:Word; 1s Compliment checksum of Structure
Identifier:Word; Increments with each ICMP_IREQ
Sequence:Word; Sequence within an ICMP_IREQ set (Used to determine Network Number of Local Subnet)

ICMP mask header

PICMPMaskHeader = ^TICMPMaskHeader;

TICMPMaskHeader = packed record

Note: Mask Request/Reply
ICMPType:Byte; ICMP_MASKREQ,ICMP_MASKREPLY
Code:Byte; Always 0
Checksum:Word; 1s Compliment checksum of Structure
Identifier:Word; Increments with each ICMP_MASKREQ
Sequence:Word; Sequence within an ICMP_MASKREQ set
Mask:TInAddr; Subnet Mask of Local Subnet (Used to determine Subnet Mask of Local Subnet)

ICMP router address

PICMPRouterAddress = ^TICMPRouterAddress;

TICMPRouterAddress = packed record

Address:TInAddr; The address of the Router on this subnet
Level:LongInt; The level of preference, higher is better

ICMP advert header

PICMPAdvertHeader = ^TICMPAdvertHeader;

TICMPAdvertHeader = packed record

ICMPType:Byte; ICMP_ROUTERADVERT
Code:Byte; Always 0
Checksum:Word; 1s Compliment checksum of Structure
EntryCount:Byte; Number of Router Address entries
EntrySize:Byte; Size of each Router Address entry
Lifetime:Word; Lifetime of entries in seconds
Routers:array[1..EntryCount] of TICMPRouterAddress; Used to advertise routers

ICMP solicit header

PICMPSolicitHeader = ^TICMPSolicitHeader;

TICMPSolicitHeader = packed record

ICMPType:Byte; ICMP_ROUTERSOLICIT
Code:Byte; Always 0
Checksum:Word; 1s Compliment checksum of Structure
Reserved:LongWord; Always 0 (Used to solicit routers)

ICMP header

PICMPHeader = ^TICMPHeader;

TICMPHeader = packed record

case Integer of  
0:(Unused:TICMPUnusedHeader);  
1:(Unreach:TICMPUnreachHeader);  
2:(Expire:TICMPExpireHeader);  
3:(Quench:TICMPQuenchHeader);  
4:(Pointer:TICMPPointerHeader);  
5:(Param:TICMPParamHeader);  
6:(Ip:TICMPIpHeader);  
7:(Redirect:TICMPRedirectHeader);  
8:(Echo:TICMPEchoHeader);  
9:(Timestamp:TICMPTimestampHeader);  
10:(Info:TICMPInfoHeader);  
11:(Mask:TICMPMaskHeader);  
12:(Advert:TICMPAdvertHeader);  
13:(Solicit:TICMPSolicitHeader);  

ICMP packet

PICMPPacket = ^TICMPPacket;

TICMPPacket = record

Note: 8 Bytes (Used by ICMPBuffer)
Size:LongWord; LongWord to keep size even
Next:PICMPPacket; Followed by RemoteAddress (4 or 16 Bytes)


Class definitions


ICMP specific classes

TICMPProtocolTransport = class(TProtocolTransport)
TICMPProtocol = class(TNetworkProtocol)
TICMPSocket = class(TProtocolSocket)
TICMPBuffer = class(TSocketBuffer)


Public variables

None defined

Function declarations


Initialization functions 

procedure ICMPInit;
Description: To be documented
Note None documented


ICMP functions 

function CheckICMP(AFamily:Word; ABuffer:Pointer):Boolean;
Description: Verify that the packet is a valid ICMP packet
Buffer The complete packet including Transport header 


function GetICMPHeaderOffset(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
Buffer The complete packet including Transport header 


function GetICMPHeaderLength(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
Buffer The complete packet including Transport header 


function GetICMPDataOffset(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
Buffer The complete packet including Transport header 


function GetICMPDataLength(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
Buffer The complete packet including Transport header 


function ChecksumICMP(AFamily:Word; ABuffer:Pointer; AOffset,ALength:Word):Word;
Description: Checksum the ICMP Header on Send/Validate the Checksum on Receive
Note None documented


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