Subversion Repositories Kolibri OS

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;                                                              ;;

;; Copyright (C) KolibriOS team 2004-2008. All rights reserved. ;;

;; Distributed under terms of the GNU General Public License    ;;

;;                                                              ;;

;;  TCP.INC                                                     ;;

;;                                                              ;;

;;  TCP Processes for Menuet OS  TCP/IP stack                   ;;

;;                                                              ;;

;;  Copyright 2002 Mike Hibbett, mikeh@oceanfree.net            ;;

;;                                                              ;;

;;  See file COPYING for details                                ;;

;;  v0.6 : Added reset handling in the established state        ;;

;;         Added a timer per socket to allow delays when        ;;

;;         rx window gets below 1KB                             ;;

;;                                                              ;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

$Revision: 1288 $

; TCP TCB states

TCB_LISTEN	   equ	      1

TCB_SYN_SENT	   equ	      2

TCB_SYN_RECEIVED   equ	      3

TCB_ESTABLISHED    equ	      4

TCB_FIN_WAIT_1	   equ	      5

TCB_FIN_WAIT_2	   equ	      6

TCB_CLOSE_WAIT	   equ	      7

TCB_CLOSING	   equ	      8

TCB_LAST_ACK	   equ	      9

TCB_TIMED_WAIT	   equ	      10

TCB_CLOSED	   equ	      11

TH_FIN	= 0x01

TH_SYN	= 0x02

TH_RST	= 0x04

TH_PUSH = 0x08

TH_ACK	= 0x10

TH_URG	= 0x20

TWOMSL		    equ     10	    ; # of secs to wait before closing socket

TCP_RETRIES	    equ 	5		; Number of times to resend a packet

TCP_TIMEOUT	    equ 	20		; resend if not replied to in x hs

;*******************************************************************

;   Interface

;

;       tcp_tx_handler      Handles the TCP transmit queue

;       tcp_rx              The protocol handler for received data

;       buildTCPPacket      fills in the packet headers and data

;       tcpStateMachine     Main state machine for received TCP packets

;       tcp_tcb_handler     1s timer, to erase tcb's in TIME_WAIT state

;

;*******************************************************************

;   TCP Payload ( Data field in IP datagram )

;

;    0                   1                   2                   3

;    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;20 |          Source Port          |       Destination Port        |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;24 |                        Sequence Number                        |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;28 |                    Acknowledgment Number                      |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;32 |  Data |           |U|A|P|R|S|F|                               |

;   | Offset| Reserved  |R|C|S|S|Y|I|            Window             |

;   |       |           |G|K|H|T|N|N|                               |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;36 |           Checksum            |         Urgent Pointer        |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;40 |                    Options                    |    Padding    |

;   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

;   |                             data

struc TCP_PACKET

{  .SourcePort	     dw  ?  ;+00

   .DestinationPort  dw  ?  ;+02

   .SequenceNumber   dd  ?  ;+04

   .AckNumber	     dd  ?  ;+08

   .DataOffset	     db  ?  ;+12 - DataOffset[0-3 bits] and Reserved[4-7]

   .Flags	     db  ?  ;+13 - Reserved[0-1 bits]|URG|ACK|PSH|RST|SYN|FIN

   .Window	     dw  ?  ;+14

   .Checksum	     dw  ?  ;+16

   .UrgentPointer    dw  ?  ;+18

   .Options	     rb  3  ;+20

   .Padding	     db  ?  ;+23

   .Data	     db  ?  ;+24

}

virtual at 0

  TCP_PACKET TCP_PACKET

end virtual

;***************************************************************************

;   Function

;      tcp_tcb_handler

;

;   Description

;       Handles sockets in the timewait state, closing them

;       when the TCB timer expires

;

;***************************************************************************

proc tcp_tcb_handler stdcall uses ebx

	; scan through all the sockets, decrementing active timers

	mov	ebx, net_sockets

	cmp	[ebx + SOCKET.NextPtr], 0

	je	.exit

	;DEBUGF	1, "K : sockets:\n"

  .next_socket:

	mov	ebx, [ebx + SOCKET.NextPtr]

	or	ebx, ebx

	jz	.exit

	;DEBUGF	1, "K :   %x-%x: %x-%x-%x-%u\n", [ebx + SOCKET.PID]:2, [ebx + SOCKET.Number]:2, [ebx + SOCKET.LocalPort]:4, [ebx + SOCKET.RemoteIP], [ebx + SOCKET.RemotePort]:4, [ebx + SOCKET.TCBState]

	cmp	[ebx + SOCKET.TCBTimer], 0

	jne	.decrement_tcb

	cmp	[ebx + SOCKET.wndsizeTimer], 0

	jne	.decrement_wnd

	jmp	.next_socket

  .decrement_tcb:

	; decrement it, delete socket if TCB timer = 0 & socket in timewait state

	dec	[ebx + SOCKET.TCBTimer]

	jnz	.next_socket

	cmp	[ebx + SOCKET.TCBState], TCB_TIMED_WAIT

	jne	.next_socket

	push	[ebx + SOCKET.PrevPtr]

	stdcall net_socket_free, ebx

	pop	ebx

	jmp	.next_socket

  .decrement_wnd:

	; TODO - prove it works!

	dec	[ebx + SOCKET.wndsizeTimer]

	jmp	.next_socket

  .exit:

	ret

endp

;***************************************************************************

;   Function

;      tcp_tx_handler

;

;   Description

;       Handles queued TCP data

;       This is a kernel function, called by stack_handler

;

;***************************************************************************

proc tcp_tx_handler stdcall

    ; decrement all resend buffers timers. If they

    ; expire, queue them for sending, and restart the timer.

    ; If the retries counter reach 0, delete the entry

	mov	esi, resendQ

	mov	ecx, 0

  .next_resendq:

	cmp	ecx, NUMRESENDENTRIES

	je	.exit		    ; None left

	cmp	dword[esi + 4], 0

	jne	@f		     ; found one

	inc	ecx

	add	esi, 8

	jmp	.next_resendq

    @@: ; we have one. decrement it's timer by 1

	dec	word[esi + 2]

	jz	@f

	inc	ecx

	add	esi, 8

	jmp	.next_resendq	    ; Timer not zero, so move on

    @@:

	xor	ebx, ebx

	; restart timer, and decrement retries

	; After the first resend, back of on next, by a factor of 5

	mov	[esi + 2], word TCP_TIMEOUT * 5

	dec	byte[esi + 1]

	jnz	@f

	; retries now 0, so delete from queue

	xchg	 [esi + 4], ebx

    @@: ; resend packet

	pushad

	mov	eax, EMPTY_QUEUE

	call	dequeue

	cmp	ax, NO_BUFFER

	jne	.tth004z

	; TODO - try again in 10ms.

	test	ebx, ebx

	jnz	@f

	mov	[esi + 4], ebx