|
|
| Line 1,144: |
Line 1,144: |
| | | <code>NextSequence:LongWord;</code> | | | <code>NextSequence:LongWord;</code> |
| | | Next Sequence number to Receive (RCV.NXT) | | | Next Sequence number to Receive (RCV.NXT) |
| | + | |- |
| | + | | <code>LastSequence:LongWord;</code> |
| | + | | Last Sequence number in Buffer (Including Unacknowledged data) |
| | |- | | |- |
| | | <code>LastAcknowledge:LongWord;</code> | | | <code>LastAcknowledge:LongWord;</code> |
| | | Last Acknowledged number to Remote | | | Last Acknowledged number to Remote |
| − | Note: NextSequence is the next byte we expect to Receive from Remote LastAcknowledge will be the first Unacknowledged Seqeunce number of the Remote. If LastAcknowledge equals NextSequence all segments have been Acknowledged. | + | Note: NextSequence is the next byte we expect to Receive from Remote. LastAcknowledge will be the first Unacknowledged Seqeunce number of the Remote. LastSequence is the last sequence we have received from the Remote. If NextSequence equals LastSequence and LastAcknowledge equals NextSequence all segments have been Acknowledged. |
| | |- | | |- |
| | |colspan="2"| | | |colspan="2"| |
| Line 1,166: |
Line 1,169: |
| | | <code>WindowScale:Byte;</code> | | | <code>WindowScale:Byte;</code> |
| | | Local Window Scale | | | Local Window Scale |
| | + | |- |
| | + | | <code>LastWindow:LongWord;</code> |
| | + | | Last Window value sent to Remote |
| | |- | | |- |
| | |colspan="2"| | | |colspan="2"| |
| Line 1,179: |
Line 1,185: |
| | | <code>NoSack:Boolean;</code> | | | <code>NoSack:Boolean;</code> |
| | | Selective Ack not in use | | | Selective Ack not in use |
| | + | |- |
| | + | | <code>function CheckIdle:Boolean;</code> |
| | + | | |
| | |- | | |- |
| | |colspan="2"| | | |colspan="2"| |
Revision as of 02:03, 21 April 2017
Return to Unit Reference
Description
Ultibo TCP (Transmission Control Protocol) unit
Notes:
Segment handling:
Send adds new segments to the end of the list only accepts ACKs for whole segments.
Recv adds/inserts segments in correct SEQ order accepts overlapping segments only sends ACKs for whole segments.
Send will coalesce small data writes into larger segments if options allow this.
Recv will store the segments exactly as received.
TCP Send and Recv do not use a block buffer as per UDP etc. Instead the data for each Segment is stored in memory (TCP_MAX_MSS) allocated with the Segment. The Free and Used values still track the amount of data in the buffer but this method allows OOB data to be handled correctly.
TCP Sequence numbers are compared using modulo 2^32 arithmetic. The following calculations provide the neccessary handling of wraparound etc.
LT = (A - B) < 0
LEQ = (A - B) <= 0
GT = (A - B) > 0
GEQ = (A - B) >= 0
See GlobalSock.pas for actual functions that implement this.
Constants
[Expand]
TCP specific constants TCP_*
| Note: Some TCP definitions are in the Protocol or IP modules
|
|
|
TCP_PROTOCOL_NAME = 'TCP';
|
|
|
|
TCP_TIMER_INTERVAL = 1;
|
1ms timer interval for TCP
|
|
|
MIN_TCP_PACKET = 20;
|
Not Counting Adapter and Transport Header
|
MAX_TCP_PACKET = 1480;
|
Not Counting Adapter and Transport Header
|
|
|
TCP_DEFAULT_MSS = 536;
|
Default Segment Size for TCP (576 - TCP - IP)
|
TCP_MAX_MSS = 1460;
|
Max Segment Size for TCP (1500 - TCP - IP)
|
|
|
TCP_MAX_LIFETIME = 120000;
|
Max Segment Lifetime (2 minutes)
|
|
|
TCP_TIMEOUT = 0;
|
Wait forever on a TCP Read/Write
|
TCP_BUFFER_SIZE = 262144;
|
65536; TCP Send/Receive Buffer Sizes
|
TCP_WINDOW_SIZE = 16060;
|
64240; Sliding Window Receive Size (44 x MSS)
|
TCP_INITIAL_WINDOW = 8192;
|
Initial Window to advertise in SYN packet
|
|
|
TCP_WINDOW_TIMEOUT = 300;
|
Time to wait before probing small/zero Window
|
TCP_ACK_TIMEOUT = 200;
|
Max Delayed Ack Time
|
|
|
TCP_CONNECT_COUNT = 3;
|
Number of Connect retries (on RST) before Failure
|
TCP_RESTART_TIMEOUT = 400;
|
Timeout between Connect retries (Milliseconds)
|
|
|
TCP_RETRY_COUNT = 10;
|
Number of Retransmits before Reset
|
|
|
TCP_RETRY_TIMEOUT:array[1..TCP_RETRY_COUNT] of LongWord = (250,500,1000,2000,4000,8000,15000,30000,60000,120000);
|
|
|
TCP_KEEPALIVE_COUNT = 3;
|
Number of Failed Keepalives before Reset
|
|
|
TCP_KEEPALIVE_TIMEOUT:array[1..TCP_KEEPALIVE_COUNT] of LongWord = (600000,60000,60000);
|
|
|
TCP_MAX_PORT = 65536;
|
|
|
|
TCP_HEADER_SIZE = 20;
|
SizeOf(TTCPHeader); Does Not Allow for Options
|
TCP_OPTIONS_SIZE = 40;
|
Maximum Allowed Options
|
|
|
TCP_SEGMENT_SIZE = 48;
|
SizeOf(TTCPSegment)
|
[Expand]
TCP socket state TCP_STATE_*
TCP_STATE_LISTEN = 0;
|
listening for connection
|
TCP_STATE_SYNSENT = 1;
|
SYN sent, active open
|
TCP_STATE_SYNREC = 2;
|
SYN received, SYNACK sent
|
TCP_STATE_ESTAB = 3;
|
established
|
TCP_STATE_FINWAIT1 = 4;
|
sent FIN
|
TCP_STATE_FINWAIT2 = 5;
|
sent FIN, received FINACK
|
TCP_STATE_CLOSWAIT = 6;
|
received FIN waiting for close
|
TCP_STATE_CLOSING = 7;
|
sent FIN, received FIN (waiting for FINACK)
|
TCP_STATE_LASTACK = 8;
|
FIN received, FINACK + FIN sent
|
TCP_STATE_TIMEWAIT = 9;
|
dally after sending final FINACK
|
TCP_STATE_CLOSED = 10;
|
FINACK received
|
[Expand]
TCP header option TCPOPT_*
TCPOPT_EOL = 0;
|
end-of-option list
|
TCPOPT_NOP = 1;
|
no-operation
|
TCPOPT_MAXSEG = 2;
|
maximum segment size
|
TCPOPT_WINDOW = 3;
|
window scale factor (rfc1072)
|
TCPOPT_SACKOK = 4;
|
selective ack ok (rfc1072)
|
TCPOPT_SACK = 5;
|
selective ack (rfc1072)
|
TCPOPT_ECHO = 6;
|
echo (rfc1072)
|
TCPOPT_ECHOREPLY = 7;
|
echo (rfc1072)
|
TCPOPT_TIMESTAMP = 8;
|
timestamps (rfc1323)
|
TCPOPT_CC = 11;
|
T/TCP CC options (rfc1644)
|
TCPOPT_CCNEW = 12;
|
T/TCP CC options (rfc1644)
|
TCPOPT_CCECHO = 13;
|
T/TCP CC options (rfc1644)
|
[Expand]
TCP header flag TCP_FLAG_*
TCP_FLAG_FIN = $01;
|
|
TCP_FLAG_SYN = $02;
|
|
TCP_FLAG_RST = $04;
|
|
TCP_FLAG_PUSH = $08;
|
|
TCP_FLAG_ACK = $10;
|
|
TCP_FLAG_URG = $20;
|
|
TCP_FLAG_MASK = $3F;
|
|
|
|
| Van Jacobson's Algorithm; max std. average and std. deviation
|
MAX_VJSA = 80000;
|
|
MAX_VJSD = 20000;
|
|
INIT_VJSA = 220;
|
|
[Expand]
TCP port TCP_PORT_*
TCP_PORT_START = 49152;
|
First dynamic port (Previously 1024) As per IANA assignment
|
TCP_PORT_STOP = 65534;
|
Last dynamic port (Previously 5000) Short of IANA assignment to allow for rollover
|
Type definitions
TCP header
[Expand]
PTCPHeader = ^TTCPHeader;
TTCPHeader = packed record
| Note: Some TCP definitions are in the Protocol or IP modules
|
| Note: 20 Bytes unless TCP Options are added
|
SourcePort:Word;
|
Network Order
|
DestPort:Word;
|
Network Order
|
Sequence:LongWord;
|
First Sequence number in Data
|
Acknowledge:LongWord;
|
Next Sequence number expected
|
HeaderLength:Byte;
|
Number of 32 bit words in Header and Options (Bits 4-7 Reserved)
|
Flags:Byte;
|
Flags for TCP Control (Bits 1-2 Reserved)
|
WindowSize:Word;
|
Max 65536 (See WindowScale for higher values)
|
Checksum:Word;
|
As per standard (Header, Options and Data)
|
Urgent:Word;
|
|
TCP segment
[Expand]
PTCPSegment = ^TTCPSegment;
TTCPSegment = record
| Note: 48 Bytes (Used by TCPSendBuffer/TCPRecvBuffer)
|
Size:Word;
|
Size of Segment Data (Can be zero)
|
Data:Pointer;
|
Pointer to Data in Buffer (Can be nil)
|
FirstSequence:LongWord;
|
Start Sequence of Data
|
LastSequence:LongWord;
|
End Sequence of Data (including Control bits)(actually the Start Sequence of next Segment)
|
|
|
Control:Word;
|
Control Bits on this segment (SYN/FIN/URG) (Send/Recv)
|
Transferred:WordBool;
|
Data has been Transferred to/from Buffer (Send/Recv)
|
Acknowledged:WordBool;
|
Data has been Acknowledged (Send/Recv)
|
SelectiveAck:WordBool;
|
Data has been Selective Acknowledged (Send/Recv)
|
RoundTripTime:Int64;
|
|
|
|
Count:Word;
|
Transmit Count (Send)
|
Timeout:Int64;
|
Transmit (Send)/Acknowledge (Recv) Timeout
|
Prev:PTCPSegment;
|
Pointer to Prev Segment
|
Next:PTCPSegment;
|
Pointer to Next Segment
|
Class definitions
TCP protocol transport
[Expand]
TTCPProtocolTransport = class(TProtocolTransport)
constructor Create;
|
|
destructor Destroy; override;
|
|
private
|
|
|
public
|
Socket:TTCPSocket;
|
Socket for responding to non matched segments
|
TCP protocol
[Expand]
TTCPProtocol = class(TNetworkProtocol)
constructor Create(AManager:TProtocolManager; const AName:String);
|
|
destructor Destroy; override;
|
|
private
|
FNextPort:Word;
|
|
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 AddTransport(ATransport:TNetworkTransport):Boolean; override;
|
|
function RemoveTransport(ATransport:TNetworkTransport):Boolean; override;
|
|
|
|
function OpenPort(ASocket:TProtocolSocket; APort:Word):Boolean; override;
|
|
function ClosePort(ASocket:TProtocolSocket):Boolean; override;
|
|
function FindPort(APort:Word; AWrite,ALock:Boolean):TProtocolPort; 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 SelectCheck(ASource,ADest:PFDSet; ACode:Integer):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 StartProtocol:Boolean; override;
|
|
function StopProtocol:Boolean; override;
|
|
function ProcessProtocol:Boolean; override;
|
|
|
|
function ProcessSockets:Boolean; override;
|
|
function ProcessSocket(ASocket:TProtocolSocket):Boolean; override;
|
|
TCP socket
[Expand]
TTCPSocket = class(TProtocolSocket)
| Note: SOCK_STREAM
|
|
|
constructor Create(AProtocol:TNetworkProtocol; ATransport:TNetworkTransport);
|
|
destructor Destroy; override;
|
|
private
|
FBackLog:Integer;
|
Backlog size of Listen/Accept Queue
|
FListener:TProtocolSocket;
|
The Listener socket for this socket (If applicable)
|
FAcceptQueue:TSocketList;
|
Sockets waiting for connection Accept
|
FReceiveQueue:TSocketList;
|
Sockets waiting for SYN/ACK handshake
|
|
|
FSendData:TTCPSendBuffer;
|
|
FRecvData:TTCPRecvBuffer;
|
|
|
|
procedure SetBackLog(ABackLog:Integer);
|
|
procedure SetListener(AListener:TProtocolSocket);
|
|
public
|
property BackLog:Integer read FBackLog write SetBackLog;
|
|
property Listener:TProtocolSocket read FListener write SetListener;
|
|
property AcceptQueue:TSocketList read FAcceptQueue;
|
|
property ReceiveQueue:TSocketList read FReceiveQueue;
|
|
|
|
property SendData:TTCPSendBuffer read FSendData;
|
|
property RecvData:TTCPRecvBuffer read FRecvData;
|
|
|
|
function GetOption(ALevel,AOptName:Integer; AOptValue:PChar; var AOptLength:Integer):Integer; override;
|
|
function SetOption(ALevel,AOptName:Integer; AOptValue:PChar; AOptLength:Integer):Integer; override;
|
|
function IoCtl(ACommand:DWORD; var AArgument:u_long):Integer; override;
|
|
|
|
function IsConnected(ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ABroadcast:Boolean):Boolean; override;
|
|
function IsListening(ALocalAddress,ARemoteAddress:Pointer; ALocalPort,ARemotePort:Word; ABroadcast:Boolean):Boolean; override;
|
|
|
|
function Listen:Boolean;
|
|
function Connect:Boolean;
|
|
function Reconnect:Boolean;
|
|
function Disconnect:Boolean;
|
|
|
|
function Accept(APeek,ALock:Boolean; AState:LongWord):TTCPSocket;
|
|
|
|
function RecvSegment(ASequence,AAcknowledge:LongWord; AWindow,AUrgent:Word; AFlags:Byte; AData:Pointer; ASize:Word):Boolean;
|
|
function SendSegment(var ASequence,AAcknowledge:LongWord; var AWindow,AUrgent:Word; var AFlags:Byte; var AData:Pointer; var ASize:Word):Boolean;
|
|
TCP state
[Expand]
TTCPState = class(TProtocolState)
constructor Create;
|
|
destructor Destroy; override;
|
|
private
|
FState:LongWord;
|
|
|
|
procedure SetState(AState:LongWord);
|
|
|
|
function GetListening:Boolean;
|
|
procedure SetListening(AValue:Boolean);
|
|
function GetEstablished:Boolean;
|
|
procedure SetEstablished(AValue:Boolean);
|
|
function GetClosed:Boolean;
|
|
procedure SetClosed(AValue:Boolean);
|
|
|
|
function GetSynchronized:Boolean;
|
|
public
|
property State:LongWord read FState write SetState;
|
|
|
|
property Listening:Boolean read GetListening write SetListening;
|
|
property Established:Boolean read GetEstablished write SetEstablished;
|
|
property Closed:Boolean read GetClosed write SetClosed;
|
|
|
|
property Synchronized:Boolean read GetSynchronized;
|
|
TCP options
[Expand]
TTCPOptions = class(TProtocolOptions)
| Note: For Get/Set Options Level = TCP_PROTO Option = TCP_NODELAY, TCP_MAXSEG etc
|
|
|
constructor Create;
|
|
destructor Destroy; override;
|
|
private
|
FMemory:TMemoryStream;
|
|
FOptions:LongWord;
|
|
|
|
FMaxSeg:Word;
|
MSS Option in TCP Header (MSS we send to Remote)
|
FWindowScale:Byte;
|
Window Scale Option in TCP Header (Window Scale we send to Remote)
|
|
|
procedure SetMaxSeg(AMaxSeg:Word);
|
|
procedure SetWindowScale(AWindowScale:Byte);
|
|
|
|
function GetOptions:Pointer;
|
|
function GetNoDelay:Boolean;
|
|
procedure SetNoDelay(ANoDelay:Boolean);
|
|
function GetNoPush:Boolean;
|
|
procedure SetNoPush(ANoPush:Boolean);
|
|
function GetNoOpt:Boolean;
|
|
procedure SetNoOpt(ANoOpt:Boolean);
|
|
function GetBsdUrgent:Boolean;
|
|
procedure SetBsdUrgent(ABsdUrgent:Boolean);
|
|
function GetNoSack:Boolean;
|
|
procedure SetNoSack(ANoSack:Boolean);
|
|
public
|
property MaxSeg:Word read FMaxSeg write SetMaxSeg;
|
|
property WindowScale:Byte read FWindowScale write SetWindowScale;
|
|
|
|
property Options:Pointer read GetOptions;
|
|
property NoDelay:Boolean read GetNoDelay write SetNoDelay;
|
Determines if we Delay small segments until previous sends are ACKed
|
property NoPush:Boolean read GetNoPush write SetNoPush;
|
|
property NoOpt:Boolean read GetNoOpt write SetNoOpt;
|
|
property BsdUrgent:Boolean read GetBsdUrgent write SetBsdUrgent;
|
|
property NoSack:Boolean read GetNoSack write SetNoSack;
|
Determines if we send SACKOK to Remote
|
TCP send buffer
[Expand]
TTCPSendBuffer = class(TSocketBuffer)
constructor Create(ASocket:TTransportSocket);
|
|
destructor Destroy; override;
|
|
private
|
FFirst:PTCPSegment;
|
Pointer to First Segment
|
FLast:PTCPSegment;
|
Pointer to Last Segment
|
|
|
function AddSegment(ASequence:LongWord; AFlags:Byte; ASize:Word):PTCPSegment;
|
|
function RemoveSegment(ASegment:PTCPSegment):Boolean;
|
|
procedure FlushSegments(All:Boolean);
|
|
protected
|
procedure SetSize(ASize:LongWord); override;
|
|
public
|
StartSequence:LongWord;
|
Initial Sequence number of Local (ISS)
|
NextSequence:LongWord;
|
Next Sequence number to Send (SND.NXT
|
LastSequence:LongWord;
|
Last Sequence number in Buffer
|
LastAcknowledge:LongWord;
|
Last Acknowledged number from Remote (SND.UNA)
Note: LastAcknowledge is the NextSequence that Remote expects to Receive or the first Unacknowledged Sequence number. If LastAcknowledge equals NextSequence all segments have been Acknowledged LastSequence is the last sequence in our buffer to send. If NextSequence equals LastSequence there is no more data to send.
|
|
|
UrgentPointer:LongWord;
|
(SND.UP)
|
|
|
MaxSeg:Word;
|
Remote Max Segment Size (Learned from Remote)
|
|
|
WindowSize:LongWord;
|
Remote Window Size (SND.WND)
|
WindowScale:Byte;
|
Remote Window Scale
|
WindowTimeout:Int64;
|
Timeout for probing small/zero Window
|
|
|
CongestionWindow:Word;
|
Slow Start Window Size
|
|
|
SynSequence:LongWord;
|
Sequence number of our SYN
|
FinSequence:LongWord;
|
Sequence number of our FIN
|
|
|
WindowSequence:LongWord;
|
Sequence number of last Window update (SND.WL1)
|
WindowAcknowledge:LongWord;
|
Acknowledge number of last Window update (SND.WL2)
|
|
|
NoPush:Boolean;
|
Disable Push on final segment
|
NoSack:Boolean;
|
Selective Ack not in use
|
NoNagle:Boolean;
|
Nagle not in use
|
|
|
VjSa:LongWord;
|
VJ's alg, standard average
|
VjSd:LongWord;
|
VJ's alg, standard deviation
|
VjLast:LongWord;
|
VJ's alg, last transmit time
|
|
|
function CheckIdle:Boolean;
|
|
|
|
function SynAcknowledged:Boolean;
|
|
function FinAcknowledged:Boolean;
|
|
|
|
function TestAcknowledge(AAcknowledge:LongWord):Boolean;
|
|
function CheckAcknowledge(AAcknowledge:LongWord):Boolean;
|
|
function ValidateAcknowledge(AAcknowledge:LongWord):Boolean;
|
|
|
|
function WriteData(var ABuffer; ASize,AFlags:Integer):Boolean;
|
|
|
|
function Finish:Boolean;
|
|
function Synchronize:Boolean;
|
|
|
|
function ReadSegment(var ASequence:LongWord; var AUrgent:Word; var AFlags:Byte; var AData:Pointer; var ASize:Word; AForce:Boolean):Boolean;
|
|
function AcknowledgeSegments(ASequence,AAcknowledge:LongWord; AWindow:Word):Boolean;
|
|
|
|
function TimestampSegment(AOptions:Pointer; var AOffset:Word):Boolean;
|
|
function SelectiveAckSegments(AOptions:Pointer; var AOffset:Word; ASize:Byte):Boolean;
|
|
TCP receive buffer
[Expand]
TTCPRecvBuffer = class(TSocketBuffer)
constructor Create(ASocket:TTransportSocket);
|
|
destructor Destroy; override;
|
|
private
|
FUrgent:LongWord;
|
Number of OOB bytes readable from Buffer
|
FAvailable:LongWord;
|
Number of bytes readable from Buffer
|
|
|
FFirst:PTCPSegment;
|
Pointer to First Segment
|
FLast:PTCPSegment;
|
Pointer to Last Segment
|
|
|
function DelayOverride(ASegment:PTCPSegment):Boolean;
|
|
|
|
function GetSegment(ASequence:LongWord; ALength:Word):PTCPSegment;
|
|
function GetPrevious(ASequence:LongWord; ALength:Word):PTCPSegment;
|
|
function GetOverlapped(ASequence:LongWord; ALength:Word):PTCPSegment;
|
|
|
|
function AddSegment(APrev:PTCPSegment; ASequence:LongWord; AFlags:Byte; ASize:Word):PTCPSegment;
|
|
function RemoveSegment(ASegment:PTCPSegment):Boolean;
|
|
procedure FlushSegments(All:Boolean);
|
|
protected
|
procedure SetSize(ASize:LongWord); override;
|
|
public
|
StartSequence:LongWord;
|
Initial Sequence number of Remote (IRS)
|
NextSequence:LongWord;
|
Next Sequence number to Receive (RCV.NXT)
|
LastSequence:LongWord;
|
Last Sequence number in Buffer (Including Unacknowledged data)
|
LastAcknowledge:LongWord;
|
Last Acknowledged number to Remote
Note: NextSequence is the next byte we expect to Receive from Remote. LastAcknowledge will be the first Unacknowledged Seqeunce number of the Remote. LastSequence is the last sequence we have received from the Remote. If NextSequence equals LastSequence and LastAcknowledge equals NextSequence all segments have been Acknowledged.
|
|
|
UrgentPointer:LongWord;
|
(RCV.UP)
|
|
|
MaxSeg:Word;
|
Local Max Segment Size
|
|
|
WindowSize:LongWord;
|
Local Window Size (RCV.WND)
|
WindowScale:Byte;
|
Local Window Scale
|
LastWindow:LongWord;
|
Last Window value sent to Remote
|
|
|
SynSequence:LongWord;
|
Sequence number of remote SYN
|
FinSequence:LongWord;
|
Sequence number of remote FIN
|
|
|
NoSack:Boolean;
|
Selective Ack not in use
|
function CheckIdle:Boolean;
|
|
|
|
function GetUrgent:LongWord;
|
|
function GetAvailable:LongWord;
|
|
|
|
function SynReceived:Boolean;
|
|
function FinReceived:Boolean;
|
|
|
|
function CheckSequence(ASequence:LongWord; ASize:Word):Boolean;
|
|
|
|
function ReadData(var ABuffer; var ASize:Integer; AFlags:Integer):Boolean;
|
|
|
|
function WriteSegment(ASequence:LongWord; AUrgent:Word; AFlags:Byte; AData:Pointer; ASize:Word):Boolean;
|
|
function AcknowledgeSegments(var AAcknowledge:LongWord; var AWindow:Word; AForce:Boolean):Boolean;
|
|
|
|
function TimestampSegment(AOptions:Pointer; var AOffset:Word):Boolean;
|
|
function SelectiveAckSegments(AOptions:Pointer; var AOffset:Word):Boolean;
|
|
Public variables
None defined
Function declarations
Initialization functions
[Expand]
procedure TCPInit;
Description: To be documented
TCP functions
[Expand]
function CheckTCP(AFamily:Word; ABuffer:Pointer):Boolean;
Description: Verify that the packet is a valid TCP packet
| Buffer
|
The complete packet including Transport header
|
[Expand]
function GetTCPHeaderOffset(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer
|
The complete packet including Transport header
|
[Expand]
function GetTCPHeaderLength(AFamily:Word; ABuffer:Pointer):Word;
Description: TO be documented
| Buffer
|
The complete packet including Transport header
|
[Expand]
function GetTCPOptionsLength(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer
|
The complete packet including Transport header
|
[Expand]
function GetTCPDataOffset(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer
|
The complete packet including Transport header
|
[Expand]
function GetTCPDataLength(AFamily:Word; ABuffer:Pointer):Word;
Description: To be documented
| Buffer
|
The complete packet including Transport header
|
[Expand]
function ChecksumTCPRecv(AFamily:Word; APseudo:PIPPseudo; ABuffer:Pointer; AOffset,ALength:Word):Word;
Description: Validate the Checksum of TCP Pseudo, Header and Data on Receive
[Expand]
function ChecksumTCPSend(AFamily:Word; APseudo:PIPPseudo; AHeader:PTCPHeader; AOptions,AData:Pointer; AOptionsLength,ADataLength:Word):Word;
Description: Checksum the TCP Pseudo, Header, Options and Data on Send
Return to Unit Reference
