Unit IGMP
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Contents
Description
Ultibo IGMP (Internet Group Management Protocol) unit
To be documented
Constants
IGMP protocol 
 IGMP_PROTOCOL_* | Note: Some IGMP definitions are in the Protocol or IP modules | |
 IGMP_PROTOCOL_NAME = 'IGMP';
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IGMP specific constants 
 IGMP_*  IGMP_TIMEOUT = 0;
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Wait forever on a IGMP Read | 
 IGMP_BUFFER_SIZE = 65536;
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IGMP Receive Buffer Size | 
 IGMP_HEADER_SIZE = 8;
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SizeOf(TIGMPHeader); | 
 IGMP_PACKET_SIZE = 8;
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SizeOf(TIGMPPacket) | 
 IGMP_QUERY_TIMEOUT = 5000;
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 IGMP_REPORT_TIMEOUT = 5000;
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 IGMP_TRANSMIT_COUNT = 3;
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Type definitions
IGMP header
PIGMPHeader = ^TIGMPHeader;
TIGMPHeader = packed record
 IGMPType:Byte;
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type of IGMP message | 
 RespTime:Byte;
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Query only otherwise 0 (Always zero in Version 1 (Assume 100)) | 
 Checksum:Word;
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1s Compliment IP-style checksum | 
 Address:TInAddr;
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group address being reported or queried (zero for "General" queries) | 
IGMP packet
PIGMPPacket = ^TIGMPPacket;
TIGMPPacket = record
| Note: 8 Bytes (Used by IGMPBuffer) | |
 Size:LongWord;
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LongWord to keep size even | 
 Next:PIGMPPacket;
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Followed by RemoteAddress (4 or 16 Bytes) | 
Class definitions
IGMP protocol transport
TIGMPProtocolTransport = class(TProtocolTransport)
 constructor Create;
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 destructor Destroy; override;
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public 
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 Socket:TIGMPSocket;
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Socket for sending replies | 
IGMP protocol
TIGMPProtocol = class(TNetworkProtocol)
 constructor Create(AManager:TProtocolManager; const AName:String);
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 destructor Destroy; override;
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private 
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 FGroups:TNetworkList;
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List of TIGMPGroup objects | 
 function PacketHandler(AHandle:THandle; ASource,ADest,APacket:Pointer; ASize:Integer; ABroadcast:Boolean):Boolean;
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 function ControlHandler(AHandle:THandle; ASource,ADest:Pointer; AProtocol,ACommand,ACode:Word; AAddress,AData:Pointer; ASize:Integer):Boolean;
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 function SendIGMP1Report(ASocket:TIGMPSocket; ASource,ADest,AAddress:Pointer):Boolean;
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 function SendIGMP2Report(ASocket:TIGMPSocket; ASource,ADest,AAddress:Pointer):Boolean;
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 function SendIGMP2Leave(ASocket:TIGMPSocket; ASource,ADest,AAddress:Pointer):Boolean;
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 function SendIGMP1Query(ASocket:TIGMPSocket; ASource,ADest,AAddress:Pointer):Boolean;
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 function SendIGMP2Query(ASocket:TIGMPSocket; ASource,ADest,AAddress:Pointer):Boolean;
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 function GetGroup(ATransport:TIGMPProtocolTransport; const AAddress:TInAddr; ALock:Boolean):TIGMPGroup;
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 function GetGroupByNext(APrevious:TIGMPGroup; ALock,AUnlock:Boolean):TIGMPGroup;
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 function AddGroup(ATransport:TIGMPProtocolTransport; const AAddress:TInAddr; const AHardware:THardwareAddress; ALock:Boolean):TIGMPGroup;
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 function RemoveGroup(ATransport:TIGMPProtocolTransport; const AAddress:TInAddr):Boolean;
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 procedure FlushGroups(All:Boolean);
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 function ProcessGroups:Boolean;
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protected 
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 function SelectCheck(ASource,ADest:PFDSet; ACode:Integer):Integer; override;
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 function SelectWait(ASocket:TProtocolSocket;ACode:Integer;ATimeout:LongWord):Integer; override;
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 function SendPacket(ASocket:TProtocolSocket; ASource,ADest:Pointer; ASourcePort,ADestPort:Word; APacket:PPacketFragment; ASize,AFlags:Integer):Integer; override;
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public 
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 function Accept(ASocket:TProtocolSocket; ASockAddr:PSockAddr; AAddrLength:PInteger):TProtocolSocket; override;
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 function Bind(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; AAddrLength:Integer):Integer; override;
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 function CloseSocket(ASocket:TProtocolSocket):Integer; override;
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 function Connect(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; AAddrLength:Integer):Integer; override;
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 function IoctlSocket(ASocket:TProtocolSocket; ACmd:DWORD; var AArg:u_long):Integer; override;
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 function GetPeerName(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; var AAddrLength:Integer):Integer; override;
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 function GetSockName(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; var AAddrLength:Integer):Integer; override;
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 function GetSockOpt(ASocket:TProtocolSocket; ALevel,AOptName:Integer; AOptValue:PChar; var AOptLength:Integer):Integer; override;
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 function Listen(ASocket:TProtocolSocket; ABacklog:Integer):Integer; override;
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 function Recv(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer):Integer; override;
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 function RecvFrom(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer; var AFromAddr:TSockAddr; var AFromLength:Integer):Integer; override;
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 function Select(ANfds:Integer; AReadfds,AWritefds,AExceptfds:PFDSet; ATimeout:PTimeVal):LongInt; override;
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 function Send(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer):Integer; override;
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 function SendTo(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer; var AToAddr:TSockAddr; AToLength:Integer):Integer; override;
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 function SetSockOpt(ASocket:TProtocolSocket; ALevel,AOptName:Integer; AOptValue:PChar; AOptLength:Integer):Integer; override;
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 function Shutdown(ASocket:TProtocolSocket; AHow:Integer):Integer; override;
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 function Socket(AFamily,AStruct,AProtocol:Integer):TProtocolSocket; override;
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 function AddTransport(ATransport:TNetworkTransport):Boolean; override;
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 function RemoveTransport(ATransport:TNetworkTransport):Boolean; override;
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 function FindSocket(AFamily,AStruct,AProtocol:Word; ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ABroadcast,AListen,ALock:Boolean; AState:LongWord):TProtocolSocket; override;
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 procedure FlushSockets(All:Boolean); override;
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 function StartProtocol:Boolean; override;
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 function StopProtocol:Boolean; override;
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 function ProcessProtocol:Boolean; override;
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IGMP group
TIGMPGroup = class(TListObject)
 constructor Create;
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 destructor Destroy; override;
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private 
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 FLock:TCriticalSectionHandle;
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 FCount:Word;
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Number of memberships | 
 FQueryTime:Int64;
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IGMP query reply timer | 
 FReportTime:Int64;
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IGMP report reply/transmit timer | 
 FTransmitCount:Word;
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IGMP report transmit counter | 
 FAddress:TInAddr;
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IP address of group | 
 FHardware:THardwareAddress;
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Hardware address of group | 
 FTransport:TNetworkTransport;
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Transport provider for group | 
 procedure SetCount(ACount:Word);
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 function GetActive:Boolean;
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 procedure SetQueryTime(const AQueryTime:Int64);
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 procedure SetReportTime(const AReportTime:Int64);
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 procedure SetTransmitCount(ATransmitCount:Word);
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 procedure SetAddress(const AAddress:TInAddr);
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 procedure SetHardware(const AHardware:THardwareAddress);
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 procedure SetTransport(ATransport:TNetworkTransport);
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public 
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 property Count:Word read FCount write SetCount;
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 property Active:Boolean read GetActive;
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 property QueryTime:Int64 read FQueryTime write SetQueryTime;
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 property ReportTime:Int64 read FReportTime write SetReportTime;
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 property TransmitCount:Word read FTransmitCount write SetTransmitCount;
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 property Address:TInAddr read FAddress write SetAddress;
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 property Hardware:THardwareAddress read FHardware write SetHardware;
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 property Transport:TNetworkTransport read FTransport write SetTransport;
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 function AcquireLock:Boolean;
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 function ReleaseLock:Boolean;
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 procedure IncrementCount;
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 procedure DecrementCount;
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 procedure IncrementTransmitCount;
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 procedure DecrementTransmitCount;
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IGMP socket
TIGMPSocket = class(TProtocolSocket)
| Note: SOCK_RAW | |
 constructor Create(AProtocol:TNetworkProtocol; ATransport:TNetworkTransport);
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 destructor Destroy; override;
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private 
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 FRecvData:TIGMPBuffer;
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public 
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 property RecvData:TIGMPBuffer read FRecvData;
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 function IoCtl(ACommand:DWORD; var AArgument:u_long):Integer; override;
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 function IsConnected(ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ABroadcast:Boolean):Boolean; override;
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 function IsListening(ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ABroadcast:Boolean):Boolean; override;
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IGMP buffer
TIGMPBuffer = class(TSocketBuffer)
 constructor Create(ASocket:TTransportSocket);
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 destructor Destroy; override;
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private 
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 FOffset:Word;
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Offset to RemoteAddress | 
 FLength:Word;
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Length of RemoteAddress | 
 FRead:Pointer;
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Pointer to Next Read from Buffer | 
 FWrite:Pointer;
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Pointer to Next Write to Buffer | 
 FCount:LongWord;
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Number of Packets in Buffer | 
 FFirst:PIGMPPacket;
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Pointer to First Packet | 
 FLast:PIGMPPacket;
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Pointer to Last Packet | 
 function AddPacket(ASize:Integer):Boolean;
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 function RemovePacket:Boolean;
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 procedure FlushPackets;
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protected 
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 procedure SetSize(ASize:LongWord); override;
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public 
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 function GetNext:Integer;
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 function GetCount:LongWord;
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 function ReadBuffer(var ABuffer; var ASize:Integer; ARemoteAddress:Pointer; AFlags:Integer):Boolean;
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 function WriteBuffer(var ABuffer; ASize:Integer; ARemoteAddress:Pointer):Boolean;
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Public variables
None defined
Function declarations
Initialization functions
procedure IGMPInit;
Description: To be documented
| Note | None documented | 
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IGMP functions
function CheckIGMP(AFamily:Word; ABuffer:Pointer):Boolean;
Description: Verify that the packet is a valid IGMP packet
| Buffer | The complete packet including Transport header | 
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function GetIGMPHeaderOffset(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer | The complete packet including Transport header | 
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function GetIGMPHeaderLength(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer | The complete packet including Transport header | 
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function GetIGMPDataOffset(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer | The complete packet including Transport header | 
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function GetIGMPDataLength(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer | The complete packet including Transport header | 
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function ChecksumIGMP(AFamily:Word; ABuffer:Pointer; AOffset,ALength:Word):Word;
Description: Checksum the IGMP Header on Send/Validate the Checksum on Receive
| Note | Checksum is calculated on the whole packet (Header and Data) | 
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