Subversion Repositories Kolibri OS

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

;;                                                                 ;;

;; Copyright (C) KolibriOS team 2004-2012. All rights reserved.    ;;

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

;;                                                                 ;;

;;  Part of the TCP/IP network stack for KolibriOS                 ;;

;;                                                                 ;;

;;   Written by hidnplayr@kolibrios.org                            ;;

;;                                                                 ;;

;;    Based on the code of 4.4BSD                                  ;;

;;                                                                 ;;

;;          GNU GENERAL PUBLIC LICENSE                             ;;

;;             Version 2, June 1991                                ;;

;;                                                                 ;;

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

$Revision: 3146 $

align 4

iglobal

        TCP_backoff     db 0,1,2,3,4,5,6,6,6,6,6,6,6

endg

macro   TCP_checksum IP1, IP2 {

;-------------

; Pseudoheader

        ; protocol type

        mov     edx, IP_PROTO_TCP

        ; source address

        add     dl, byte [IP1+1]

        adc     dh, byte [IP1+0]

        adc     dl, byte [IP1+3]

        adc     dh, byte [IP1+2]

        ; destination address

        adc     dl, byte [IP2+1]

        adc     dh, byte [IP2+0]

        adc     dl, byte [IP2+3]

        adc     dh, byte [IP2+2]

        ; size

        adc     dl, cl

        adc     dh, ch

        adc     edx, 0

;---------------------

; Real header and data

        push    esi

        call    checksum_1

        call    checksum_2

        pop     esi

}       ; returns in dx only

macro   TCP_sendseqinit ptr {

        push    edi                     ;;;; i dont like this static use of edi

        mov     edi, [ptr + TCP_SOCKET.ISS]

        mov     [ptr + TCP_SOCKET.SND_UP], edi

        mov     [ptr + TCP_SOCKET.SND_MAX], edi

        mov     [ptr + TCP_SOCKET.SND_NXT], edi

        mov     [ptr + TCP_SOCKET.SND_UNA], edi

        pop     edi

}

macro   TCP_rcvseqinit ptr {

        push    edi

        mov     edi, [ptr + TCP_SOCKET.IRS]

        inc     edi

        mov     [ptr + TCP_SOCKET.RCV_NXT], edi

        mov     [ptr + TCP_SOCKET.RCV_ADV], edi

        pop     edi

}

macro   TCP_init_socket socket {

        mov     [socket + TCP_SOCKET.t_maxseg], TCP_mss_default

        mov     [socket + TCP_SOCKET.t_flags], TF_REQ_SCALE or TF_REQ_TSTMP

        mov     [socket + TCP_SOCKET.t_srtt], TCP_time_srtt_default

        mov     [socket + TCP_SOCKET.t_rttvar], TCP_time_rtt_default * 4

        mov     [socket + TCP_SOCKET.t_rttmin], TCP_time_re_min

;;; TODO: TCP_time_rangeset

        mov     [socket + TCP_SOCKET.SND_CWND], TCP_max_win shl TCP_max_winshift

        mov     [socket + TCP_SOCKET.SND_SSTHRESH], TCP_max_win shl TCP_max_winshift

}

;---------------------------

;

; TCP_pull_out_of_band

;

; IN:  eax =

;      ebx = socket ptr

;      edx = tcp packet ptr

;

; OUT: /

;

;---------------------------

align 4

TCP_pull_out_of_band:

        DEBUGF  1,"TCP_pull_out_of_band\n"

        ;;;; 1282-1305

        ret

;-------------------------

;

; TCP_drop

;

;  IN:  eax = socket ptr

;       ebx = error number

;

;  OUT: eax = socket ptr

;

;-------------------------

align 4

TCP_drop:

        DEBUGF  1,"TCP_drop: %x\n", eax

        cmp     [eax + TCP_SOCKET.t_state], TCPS_SYN_RECEIVED

        jb      .no_syn_received

        mov     [eax + TCP_SOCKET.t_state], TCPS_CLOSED

        call    TCP_output

;;; TODO: update stats

        jmp     TCP_close

  .no_syn_received:

;;; TODO: update stats

;;; TODO: check if error code is "Connection timed out' and handle accordingly

        mov     [eax + SOCKET.errorcode], ebx

;-------------------------

;

; TCP_close

;

;  IN:  eax = socket ptr

;  OUT: eax = socket ptr

;

;-------------------------

align 4

TCP_close:

        DEBUGF  1,"TCP_close: %x\n", eax

;;; TODO: update RTT and mean deviation

;;; TODO: update slow start threshold

        call    SOCKET_is_disconnected

        ret

;-------------------------

;

; TCP_outflags

;

;  IN:  eax = socket ptr

;

;  OUT: edx = flags

;

;-------------------------

align 4

TCP_outflags:

        mov     edx, [eax + TCP_SOCKET.t_state]

        movzx   edx, byte [edx + .flaglist]

        DEBUGF  1,"TCP_outflags: socket=%x flags=%x\n", eax, dl

        ret

  .flaglist:

        db      TH_RST + TH_ACK         ; TCPS_CLOSED

        db      0                       ; TCPS_LISTEN

        db      TH_SYN                  ; TCPS_SYN_SENT

        db      TH_SYN + TH_ACK         ; TCPS_SYN_RECEIVED

        db               TH_ACK         ; TCPS_ESTABLISHED

        db               TH_ACK         ; TCPS_CLOSE_WAIT

        db      TH_FIN + TH_ACK         ; TCPS_FIN_WAIT_1

        db      TH_FIN + TH_ACK         ; TCPS_CLOSING

        db      TH_FIN + TH_ACK         ; TCPS_LAST_ACK

        db               TH_ACK         ; TCPS_FIN_WAIT_2

        db               TH_ACK         ; TCPS_TIMED_WAIT

;---------------------------------------

;

; The fast way to send an ACK/RST/keepalive segment

;

; TCP_respond

;

;  IN:  ebx = socket ptr

;        cl = flags

;

;--------------------------------------

align 4

TCP_respond:

        DEBUGF  1,"TCP_respond_socket: socket=%x flags=%x\n", ebx, cl

;---------------------

; Create the IP packet

        push    cx ebx

        mov     eax, [ebx + IP_SOCKET.RemoteIP]

        mov     edx, [ebx + IP_SOCKET.LocalIP]

        mov     ecx, sizeof.TCP_header

        mov     di, IP_PROTO_TCP shl 8 + 128

        call    IPv4_output

        test    edi, edi

        jz      .error

        pop     esi cx

        push    edx eax

;-----------------------------------------------

; Fill in the TCP header by using the socket ptr

        mov     ax, [esi + TCP_SOCKET.LocalPort]

        stosw

        mov     ax, [esi + TCP_SOCKET.RemotePort]

        stosw

        mov     eax, [esi + TCP_SOCKET.SND_NXT]

        bswap   eax

        stosd

        mov     eax, [esi + TCP_SOCKET.RCV_NXT]

        bswap   eax

        stosd

        mov     al, 0x50        ; Dataoffset: 20 bytes (TCP_header.DataOffset)

        stosb

        mov     al, cl

        stosb

;        mov     ax, [esi + TCP_SOCKET.RCV_WND]

;        rol     ax, 8

        mov     ax, 0x00a0      ;;;;;;; FIXME

        stosw                   ; window

        xor     eax, eax

        stosd                   ; checksum + urgentpointer

;---------------------

; Fill in the checksum

  .checksum:

        sub     edi, sizeof.TCP_header

        mov     ecx, sizeof.TCP_header

        xchg    esi, edi

        TCP_checksum (edi + IP_SOCKET.LocalIP), (edi + IP_SOCKET.RemoteIP)

        mov     [esi+TCP_header.Checksum], dx

;--------------------

; And send the segment

        call    [ebx + NET_DEVICE.transmit]

        ret

  .error:

        DEBUGF  1,"TCP_respond_socket: failed\n"

        add     esp, 2 + 4

        ret

;-------------------------

; TCP_respond.segment:

;

;  IN:  edx = segment ptr (a previously received segment)

;       edi = ptr to dest and src IPv4 addresses

;        cl = flags

align 4

TCP_respond_segment:

        DEBUGF  1,"TCP_respond_segment: frame=%x flags=%c\n", edx, cl

;---------------------

; Create the IP packet

        push    cx edx

        mov     ebx, [edi + 4]

        mov     eax, [edi]

        mov     ecx, sizeof.TCP_header

        mov     di , IP_PROTO_TCP shl 8 + 128

        call    IPv4_output

        jz      .error

        pop     esi cx

        push    edx eax

;---------------------------------------------------

; Fill in the TCP header by using a received segment

        mov     ax, [esi + TCP_header.DestinationPort]

        stosw

        mov     ax, [esi + TCP_header.SourcePort]

        stosw

        mov     eax, [esi + TCP_header.AckNumber]

        bswap   eax

        stosd

        xor     eax, eax

        stosd

        mov     al, 0x50        ; Dataoffset: 20 bytes (sizeof.TCP_header)

        stosb

        mov     al, cl

        stosb

        mov     ax, 1280

        rol     ax, 8

        stosw                   ; window

        xor     eax, eax

        stosd                   ; checksum + urgentpointer

;---------------------

; Fill in the checksum

  .checksum:

        lea     esi, [edi - sizeof.TCP_header]

        mov     ecx, sizeof.TCP_header

        TCP_checksum (esi - sizeof.IPv4_header + IPv4_header.DestinationAddress),\      ; FIXME

                     (esi - sizeof.IPv4_header + IPv4_header.SourceAddress)

        mov     [esi+TCP_header.Checksum], dx

;--------------------

; And send the segment

        call    [ebx + NET_DEVICE.transmit]

        ret

  .error:

        DEBUGF  1,"TCP_respond_segment: failed\n"

        add     esp, 2+4

        ret

macro   TCPT_RANGESET   timer, value, min, max {

local   .min

local   .max

local   .done

        cmp     value, min

        jb      .min

        cmp     value, max

        ja      .max

        mov     timer, value

        jmp     .done

  .min:

        mov     timer, value

        jmp     .done

  .max:

        mov     timer, value

        jmp     .done

  .done:

}

align 4

TCP_set_persist:

; First, check if retransmit timer is not set, retransmit and persist are mutually exclusive

        cmp     [eax + TCP_SOCKET.timer_retransmission], 0

        jg      @f

; calculate RTO

        push    ebx

        mov     ebx, [eax + TCP_SOCKET.t_srtt]

        shr     ebx, 2

        add     ebx, [eax + TCP_SOCKET.t_rttvar]

        shr     ebx, 1

        mov     cl, [eax + TCP_SOCKET.t_rxtshift]

        shl     ebx, cl

; Start/restart persistance timer.

        TCPT_RANGESET   [eax + TCP_SOCKET.timer_persist], ebx, TCP_time_pers_min, TCP_time_pers_max

        pop     ebx

        cmp     [eax + TCP_SOCKET.t_rxtshift], TCP_max_rxtshift

        jae     @f

        inc     [eax + TCP_SOCKET.t_rxtshift]

      @@:

        ret

; eax = rtt

; ebx = socket ptr

align 4

TCP_xmit_timer:

        DEBUGF  1,"TCP_xmit_timer: socket=%x rtt=%d0ms\n", ebx, eax

;TODO: update stats

        cmp     [ebx + TCP_SOCKET.t_rtt], 0

        je      .no_rtt_yet

; srtt is stored as a fixed point with 3 bits after the binary point.

; The following magic is equivalent of the smoothing algorithm in rfc793 with an alpha of .875

; (srtt = rtt/8 + srtt*7/8 in fixed point)

; Adjust rtt to origin 0.

        push    ecx

        mov     ecx, [ebx + TCP_SOCKET.t_srtt]

        shr     ecx, TCP_RTT_SHIFT

        sub     eax, ecx

        dec     eax

        pop     ecx

        add     [ebx + TCP_SOCKET.t_srtt], eax

        ja      @f

        mov     [ebx + TCP_SOCKET.t_srtt], 1

  @@:

; We accumulate a smoothed rtt variance (actually, a smoothed mean difference),

; then set the retransmit timer to smoothed rtt + 4 times the smoothed variance.

; rttvar is stored as fixed point with 2 bits after the binary point.

; The following is equivalent to rfc793 smoothing with an alpha of .75

; (rttvar = rttvar*3/4 + delta/4) (delta = eax)

; get abs(eax)

        push    edx

        cdq

        xor     eax, edx

        sub     eax, edx

        mov     edx, [ebx + TCP_SOCKET.t_rttvar]

        shr     edx, TCP_RTTVAR_SHIFT

        sub     eax, edx

        pop     edx

        add     [ebx + TCP_SOCKET.t_rttvar], eax

        ja      @f

        mov     [ebx + TCP_SOCKET.t_rttvar], 1

  @@:

        ret

  .no_rtt_yet:

        push    ecx

        mov     ecx, eax

        shl     ecx, TCP_RTT_SHIFT

        mov     [ebx + TCP_SOCKET.t_srtt], ecx

        shl     eax, TCP_RTTVAR_SHIFT - 1

        mov     [ebx + TCP_SOCKET.t_rttvar], eax

        pop     ecx

        ret

; eax = max segment size

; ebx = socket ptr

align 4

TCP_mss:

        cmp     eax, 1420                               ; FIXME

        jbe     @f

        mov     eax, 1420

  @@:

        mov     [ebx + TCP_SOCKET.t_maxseg], eax

        ret