TTCPProtocol

Return to Unit TCP

Description

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To be documented

Class definitions

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TTCPProtocol = class(TNetworkProtocol)

constructor Create(AManager:TProtocolManager; const AName:String);
destructor Destroy; override;
private
FNextPort:Word;
FMinBacklog:Integer;
FMaxBacklog:Integer;
FReceiveBacklog:Integer;
function PacketHandler(AHandle:THandle; ASource,ADest,APacket:Pointer; ASize:Integer; ABroadcast:Boolean):Boolean;
function SegmentHandler(ASocket:TTCPSocket; ASource,ADest,APacket:Pointer; ASize:Integer):Boolean;
function ResetHandler(ASocket:TTCPSocket; ASource,ADest,APacket:Pointer; ASize:Integer):Boolean;
function CloneSocket(ASocket:TTCPSocket; ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ALock:Boolean; AState:LongWord):TTCPSocket;
function GetTCPOptionsSize(ASocket:TTCPSocket; AOptions:Pointer):Word;
function CreateTCPOptions(ASocket:TTCPSocket; AOptions:Pointer; AFlags:Byte):Boolean;
function HandleTCPOptions(ASocket:TTCPSocket; AOptions:Pointer; AFlags:Byte):Boolean;
function InsertTCPOption(ASocket:TTCPSocket; AOptions:Pointer; AOption:Byte):Boolean;
function ExtractTCPOption(ASocket:TTCPSocket; AOptions:Pointer; AOption:Byte):Boolean;
function SendReset(ASocket:TTCPSocket):Boolean;
function SendAcknowledge(ASocket:TTCPSocket):Boolean;
function SendSegment(ASocket:TTCPSocket; ASource,ADest:Pointer; ASourcePort,ADestPort:Word; ASequence,AAcknowledge:LongWord; AWindow,AUrgent:Word; AFlags:Byte; AOptions,AData:Pointer; ASize:Integer):Integer;
protected
function OpenPort(ASocket:TProtocolSocket; APort:Word):Boolean; override;
function ClosePort(ASocket:TProtocolSocket):Boolean; override;
function FindPort(APort:Word; AWrite,ALock:Boolean):TProtocolPort; override;
function SelectCheck(ASource,ADest:PFDSet; ACode:Integer):Integer; override;
function SelectWait(ASocket:TProtocolSocket; ACode:Integer; ATimeout:LongWord):Integer; override;
public
function Accept(ASocket:TProtocolSocket; ASockAddr:PSockAddr; AAddrLength:PInteger):TProtocolSocket; override;
function Bind(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; AAddrLength:Integer):Integer; override;
function CloseSocket(ASocket:TProtocolSocket):Integer; override;
function Connect(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; AAddrLength:Integer):Integer; override;
function IoctlSocket(ASocket:TProtocolSocket; ACmd:DWORD; var AArg:u_long):Integer; override;
function GetPeerName(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; var AAddrLength:Integer):Integer; override;
function GetSockName(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; var AAddrLength:Integer):Integer; override;
function GetSockOpt(ASocket:TProtocolSocket; ALevel,AOptName:Integer; AOptValue:PChar; var AOptLength:Integer):Integer; override;
function Listen(ASocket:TProtocolSocket; ABacklog:Integer):Integer; override;
function Recv(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer):Integer; override;
function RecvFrom(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer; var AFromAddr:TSockAddr; var AFromLength:Integer):Integer; override;
function Select(ANfds:Integer; AReadfds,AWritefds,AExceptfds:PFDSet; ATimeout:PTimeVal):LongInt; override;
function Send(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer):Integer; override;
function SendTo(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer; var AToAddr:TSockAddr; AToLength:Integer):Integer; override;
function SetSockOpt(ASocket:TProtocolSocket; ALevel,AOptName:Integer; AOptValue:PChar; AOptLength:Integer):Integer; override;
function Shutdown(ASocket:TProtocolSocket; AHow:Integer):Integer; override;
function Socket(AFamily,AStruct,AProtocol:Integer):TProtocolSocket; override;
function AddTransport(ATransport:TNetworkTransport):Boolean; override;
function RemoveTransport(ATransport:TNetworkTransport):Boolean; override;
function FindSocket(AFamily,AStruct,AProtocol:Word; ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ABroadcast,AListen,ALock:Boolean; AState:LongWord):TProtocolSocket; override;
procedure FlushSockets(All:Boolean); override;
function StartProtocol:Boolean; override;
function StopProtocol:Boolean; override;
function ProcessProtocol:Boolean; override;
function ProcessSockets:Boolean; override;
function ProcessSocket(ASocket:TProtocolSocket):Boolean; override;

Function declarations

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constructor TTCPProtocol.Create(AManager:TProtocolManager; const AName:String);

Description: To be documented

Note	None documented

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destructor TTCPProtocol.Destroy;

Description: To be documented

Note	None documented

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function TTCPProtocol.PacketHandler(AHandle:THandle; ASource,ADest,APacket:Pointer; ASize:Integer; ABroadcast:Boolean):Boolean;

Description: Process a packet received by a Transport

Handle	The Handle of the Protocol Transport the packet was received from
Source	The source address of the received packet (Set by Transport)
Dest	The destination address of the received packet (Set by Transport)
Packet	The received packet (The complete packet including Transport header)
Size	The size of the received packet in bytes
Broadcast	True if the destination address is a broadcast address

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function TTCPProtocol.SegmentHandler(ASocket:TTCPSocket; ASource,ADest,APacket:Pointer; ASize:Integer):Boolean;

Description: Check Socket state and feed Segments to the Sockets, discarding or resetting invalid Segments

Packet	The received packet (The complete packet including Transport header)
Note	Initial validity check on SEQ/ACK and Flags is done here Caller must hold the Socket lock

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function TTCPProtocol.ResetHandler(ASocket:TTCPSocket; ASource,ADest,APacket:Pointer; ASize:Integer):Boolean;

Description: Send a Reset using the appropriate values from SEQ and ACK

Packet	The received packet (The complete packet including Transport header)
Note	Must never send a Reset if RST bit is set in Packet Caller must hold the Socket lock

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function TTCPProtocol.CloneSocket(ASocket:TTCPSocket; ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ALock:Boolean; AState:LongWord):TTCPSocket;

Description: Creates a cloned Socket based on the supplied socket with Options etc copied from the original

Note	New Socket will be SS_UNCONNECTED and TCP_STATE_CLOSED but with the Local and Remote address and port bindings completed (different to a new Socket) Addresses and Ports are passed in Host order Caller must hold the Socket lock

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function TTCPProtocol.GetTCPOptionsSize(ASocket:TTCPSocket; AOptions:Pointer):Word;

Description: Returns the Size of the Options currently in the buffer with padding to 32 bits

Note	Caller must hold the Socket lock

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function TTCPProtocol.CreateTCPOptions(ASocket:TTCPSocket; AOptions:Pointer; AFlags:Byte):Boolean;

Description: To be documented

Note	Caller must hold the Socket lock

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function TTCPProtocol.HandleTCPOptions(ASocket:TTCPSocket; AOptions:Pointer; AFlags:Byte):Boolean;

Description: To be documented

Note	Caller must hold the Socket lock

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function TTCPProtocol.InsertTCPOption(ASocket:TTCPSocket; AOptions:Pointer; AOption:Byte):Boolean;

Description: Inserts the Option into the buffer from the supplied Socket

Note	Caller must hold the Socket lock

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function TTCPProtocol.ExtractTCPOption(ASocket:TTCPSocket; AOptions:Pointer; AOption:Byte):Boolean;

Description: Extracts the Option from the buffer to the supplied Socket

Note	Caller must hold the Socket lock

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function TTCPProtocol.SendReset(ASocket:TTCPSocket):Boolean;

Description: Sends an RST in order to abort an existing connection

Note	Not called in response to a bad segment (done by ResetHandler) May be invoked by calling CloseSocket with a hard close etc Caller must hold the Socket lock

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function TTCPProtocol.SendAcknowledge(ASocket:TTCPSocket):Boolean;

Description: Sends an ACK possibly in response to a bad segment or due to a keep alive etc

Note	Caller must hold the Socket lock

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function TTCPProtocol.SendSegment(ASocket:TTCPSocket; ASource,ADest:Pointer; ASourcePort,ADestPort:Word; ASequence,AAcknowledge:LongWord; AWindow,AUrgent:Word; AFlags:Byte; AOptions,AData:Pointer; ASize:Integer):Integer;

Description: Send Segment adds the Protocol Header and other details to the Data

Note	Both Options and Data can be nil, Size can be zero. Used instead of SendPacket to allow for the extra parameters needed by TCP Addresses and Ports are passed in Host order Caller must hold the Socket lock

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function TTCPProtocol.OpenPort(ASocket:TProtocolSocket; APort:Word):Boolean;

Description: To be documented

Note	Caller must hold the Socket lock

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function TTCPProtocol.ClosePort(ASocket:TProtocolSocket):Boolean;

Description: To be documented

Note	Caller must hold the Socket lock

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function TTCPProtocol.FindPort(APort:Word; AWrite,ALock:Boolean):TProtocolPort;

Description: Find a protocol port for the specified port number

Port	The port number to find
Write	If True then use the writer lock
Lock	If True then lock the found entry before returning

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function TTCPProtocol.SelectCheck(ASource,ADest:PFDSet; ACode:Integer):Integer;

Description: To be documented

Source	Source is the working set to check
Dest	Dest is the set passed to Select

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function TTCPProtocol.SelectWait(ASocket:TProtocolSocket; ACode:Integer; ATimeout:LongWord):Integer;

Description: To be documented

Socket	Socket is the single socket to check
Code	Code is the type of check
Timeout	Timeout is how long to wait

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function TTCPProtocol.Accept(ASocket:TProtocolSocket; ASockAddr:PSockAddr; AAddrLength:PInteger):TProtocolSocket;

Description: BSD compatible Accept

Socket	The socket to accept from
SockAddr	The socket address (Network Order)
AddrLength	The socket address length
Note	SockAddr is returned in Network order Caller must hold the Socket lock

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function TTCPProtocol.Bind(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; AAddrLength:Integer):Integer;

Description: BSD compatible Bind

Socket	The socket to bind
SockAddr	The socket address (Network Order)
AddrLength	The socket address length
Note	Sets the LocalAddress/Port for future Sends and Receives, Address can be specified as INADDR_ANY which allows Listening or auto assignment. If Port is IPPORT_ANY then a dynamic Port will be assigned. SockAddr is passed in Network order Caller must hold the Socket lock

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function TTCPProtocol.CloseSocket(ASocket:TProtocolSocket):Integer;

Description: BSD compatible Close Socket

Socket	The socket to close
Note	Closes and removes the socket, does not perform Linger Caller must hold the Socket lock

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function TTCPProtocol.Connect(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; AAddrLength:Integer):Integer;

Description: BSD compatible Connect

Socket	The socket to connect
SockAddr	The socket address (Network Order)
AddrLength	The socket address length
Note	Sets the RemoteAddress/Port of future Sends and Receives and begins the three way handshake, if Bind has not been called then the LocalAddress/Port will be set appropriately as well based on the route to the RemoteAddress. SockAddr is passed in Network order Caller must hold the Socket lock

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function TTCPProtocol.IoctlSocket(ASocket:TProtocolSocket; ACmd:DWORD; var AArg:u_long):Integer;

Description: BSD compatible IO Control Socket

Socket	The socket to control
Cmd	The socket command
Arg	The command argument
Note	Caller must hold the Socket lock

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function TTCPProtocol.GetPeerName(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; var AAddrLength:Integer):Integer;

Description: BSD compatible Get Peer Name (Remote)

Socket	The socket to get from
SockAddr	The socket address (Network Order)
AddrLength	The socket address length
Note	SockAddr is returned in Network order Caller must hold the Socket lock

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function TTCPProtocol.GetSockName(ASocket:TProtocolSocket; var ASockAddr:TSockAddr; var AAddrLength:Integer):Integer;

Description: BSD compatible Get Sock Name (Local)

Socket	The socket to get from
SockAddr	The socket address (Network Order)
AddrLength	The socket address length
Note	SockAddr is returned in Network order Caller must hold the Socket lock

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function TTCPProtocol.GetSockOpt(ASocket:TProtocolSocket; ALevel,AOptName:Integer; AOptValue:PChar; var AOptLength:Integer):Integer;

Description: BSD compatible Get Socket Option

Socket	The socket to get the option from
Level	The protocol level for the option
OptName	The name of the option to get
OptValue	The value of the option
OptLength	The length of the option
Note	Caller must hold the Socket lock

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function TTCPProtocol.Listen(ASocket:TProtocolSocket; ABacklog:Integer):Integer;

Description: BSD compatible Listen

Socket	The socket to listen on
Backlog	Queue depth for accepted connections
Note	Caller must hold the Socket lock

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function TTCPProtocol.Recv(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer):Integer;

Description: BSD compatible Receive

Socket	The socket to receive from
Buffer	Buffer for received data
Length	Length of buffer in bytes
Flags	Protocol specific receive flags
Note	Caller must hold the Socket lock

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function TTCPProtocol.RecvFrom(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer; var AFromAddr:TSockAddr; var AFromLength:Integer):Integer;

Description: BSD compatible Receive From

Socket	The socket to receive from
Buffer	Buffer for received data
Length	Length of buffer in bytes
Flags	Protocol specific receive flags
FromAddr	The address the data was received from (Network Order)
FromLength	The length of the address
Note	TCP treats RecvFrom as Recv Caller must hold the Socket lock

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function TTCPProtocol.Send(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer):Integer;

Description: BSD compatible Send

Socket	The socket to send to
Buffer	Buffer for data to send
Length	Length of buffer in bytes
Flags	Protocol specific send flags
Note	Caller must hold the Socket lock

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function TTCPProtocol.SendTo(ASocket:TProtocolSocket; var ABuffer; ALength,AFlags:Integer; var AToAddr:TSockAddr; AToLength:Integer):Integer;

Description: BSD compatible Send To

Socket	The socket to send to
Buffer	Buffer for data to send
Length	Length of buffer in bytes
Flags	Protocol specific send flags
ToAddr	The socket address to send to (Network Order)
ToLength	The length of the socket address
Note	TCP treats SendTo as Send Caller must hold the Socket lock

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function TTCPProtocol.SetSockOpt(ASocket:TProtocolSocket; ALevel,AOptName:Integer; AOptValue:PChar; AOptLength:Integer):Integer;

Description: BSD compatible Set Socket Option

Socket	The socket to set the option for
Level	The protocol level for the option
OptName	The name of the option to set
OptValue	The value of the option
OptLength	The length of the option
Note	Caller must hold the Socket lock

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function TTCPProtocol.Shutdown(ASocket:TProtocolSocket; AHow:Integer):Integer;

Description: BSD compatible Shutdown

Socket	The socket to shutdown
How	The direction to shutdown the socket
Note	Shutdown does not result in CloseSocket so Closed must not get set Caller must hold the Socket lock

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function TTCPProtocol.Socket(AFamily,AStruct,AProtocol:Integer):TProtocolSocket;

Description: BSD compatible Socket (Create a new socket)

Family	Socket address family (eg AF_INET)
Struct	Socket type (eg SOCK_DGRAM)
Protocol	Socket protocol (eg IPPROTO_UDP)
Note	When a Socket is created it will be SS_UNCONNECTED and TCP_STATE_CLOSED

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function TTCPProtocol.AddTransport(ATransport:TNetworkTransport):Boolean;

Description: Add a transport to this protocol

Transport	The transport to add

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function TTCPProtocol.RemoveTransport(ATransport:TNetworkTransport):Boolean;

Description: Remove a transport from this protocol

Transport	The transport to remove

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function TTCPProtocol.FindSocket(AFamily,AStruct,AProtocol:Word; ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ABroadcast,AListen,ALock:Boolean; AState:LongWord):TProtocolSocket;

Description: Find a protocol socket based on all relevant parameters

Family	Socket address family (eg AF_INET)
Struct	Socket type (eg SOCK_DGRAM)
Protocol	Socket protocol (eg IPPROTO_UDP)
LocalAddress	Local transport address to match (Host Order)
RemoteAddress	Remote transport address to match (Host Order)
LocalPort	Local port to match (Host Order)
RemotePort	Remote port to match (Host Order)
Broadcast	If True then match broadcast addresses
Listen	If True then match only listening sockets
Lock	If True then lock the found entry before returning

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procedure TTCPProtocol.FlushSockets(All:Boolean);

Description: Flush sockets from the socket cache

All	If True flush all sockets, otherwise flush expired sockets.

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function TTCPProtocol.StartProtocol:Boolean;

Description: Start this protocol ready for sending and receiving

Note	None documented

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function TTCPProtocol.StopProtocol:Boolean;

Description: Stop this protocol ready for removal

Note	None documented

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function TTCPProtocol.ProcessProtocol:Boolean;

Description: Process periodic tasks for this protocol

Note	None documented

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function TTCPProtocol.ProcessSockets:Boolean;

Description: Process periodic tasks for protocol sockets

Note	None documented

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function TTCPProtocol.ProcessSocket(ASocket:TProtocolSocket):Boolean;

Description: Process periodic tasks for a protocol socket

Note	None documented

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