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: 2555 $

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

;

; TCP_output

;

; IN:  eax = socket pointer

;

; OUT: /

;

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

align 4

TCP_output:

        DEBUGF 1,"TCP_output, socket: %x\n", eax

; We'll detect the length of the data to be transmitted, and flags to be used

; If there is some data, or any critical controls to send (SYN / RST), then transmit

; Otherwise, investigate further

        mov     ebx, [eax + TCP_SOCKET.SND_MAX]

        cmp     ebx, [eax + TCP_SOCKET.SND_UNA]

        jne     .not_idle

        mov     ebx, [eax + TCP_SOCKET.t_idle]

        cmp     ebx, [eax + TCP_SOCKET.t_rxtcur]

        jbe     .not_idle

; We have been idle for a while and no ACKS are expected to clock out any data we send..

; Slow start to get ack "clock" running again.

        mov     ebx, [eax + TCP_SOCKET.t_maxseg]

        mov     [eax + TCP_SOCKET.SND_CWND], ebx

  .not_idle:

  .again:

        mov     ebx, [eax + TCP_SOCKET.SND_NXT]         ; calculate offset (71)

        sub     ebx, [eax + TCP_SOCKET.SND_UNA]         ;

        mov     ecx, [eax + TCP_SOCKET.SND_WND]         ; determine window

        cmp     ecx, [eax + TCP_SOCKET.SND_CWND]        ;

        jb      @f                                      ;

        mov     ecx, [eax + TCP_SOCKET.SND_CWND]        ;

       @@:                                              ;

        call    TCP_outflags                            ; flags in dl

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

; data being forced out ?

; If in persist timeout with window of 0, send 1 byte.

; Otherwise, if window is small but nonzero, and timer expired,

; we will send what we can and go to transmit state

        test    [eax + TCP_SOCKET.t_force], -1

        jz      .no_force

        test    ecx, ecx

        jnz     .no_zero_window

        cmp     ebx, [eax + STREAM_SOCKET.snd.size]

        jae     @f

        and     dl, not (TH_FIN)          ; clear the FIN flag    ??? how can it be set before?

       @@:

        inc     ecx

        jmp     .no_force

  .no_zero_window:

        mov     [eax + TCP_SOCKET.timer_persist], 0

        mov     [eax + TCP_SOCKET.t_rxtshift], 0

  .no_force:

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

; Calculate how much data to send (106)

        mov     esi, [eax + STREAM_SOCKET.snd.size]

        cmp     esi, ecx

        jb      @f

        mov     esi, ecx

       @@:

        sub     esi, ebx

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

; check for window shrink (107)

; If FIN has been set, but not ACKed, but we havent been called to retransmit, esi will be -1

; Otherwise, window shrank after we sent into it.

        jns     .not_negative

; enter persist state

        xor     esi, esi

; If window shrank to 0

        test    ecx, ecx

        jnz     @f

; cancel pending retransmit

        mov     [eax + TCP_SOCKET.timer_retransmission], 0

; pull SND_NXT back to (closed) window, We will enter persist state below.

        push    [eax + TCP_SOCKET.SND_UNA]

        pop     [eax + TCP_SOCKET.SND_NXT]

       @@:

; If window didn't close completely, just wait for an ACK

  .not_negative:

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

; Send one segment at a time (124)

        cmp     esi, [eax + TCP_SOCKET.t_maxseg]

        jbe     @f

        mov     esi, [eax + TCP_SOCKET.t_maxseg]

;;; sendalot = 1

       @@:

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

; Turn of FIN flag if send buffer not emptied (128)

        mov     edi, [eax + TCP_SOCKET.SND_NXT]

        add     edi, esi

        sub     edi, [eax + TCP_SOCKET.SND_UNA]

        sub     edi, [eax + STREAM_SOCKET.snd.size]

        jns     @f

        and     dl, not (TH_FIN)

       @@:

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

; calculate window advertisement (130)

        mov     ecx, SOCKET_MAXDATA

        sub     ecx, [eax + STREAM_SOCKET.rcv.size]

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

; Sender silly window avoidance (131)

        test    esi, esi

        jz      .len_zero

        cmp     esi, [eax + TCP_SOCKET.t_maxseg]

        je      .send

        test    [eax + TCP_SOCKET.t_flags], TF_NODELAY

        jnz     @f

        ; TODO: if not 'idle', skip to next codeblock

       @@:

        add     ebx, esi

        cmp     ebx, [eax + STREAM_SOCKET.snd.size]

        jae     .send

        test    [eax + TCP_SOCKET.t_force], -1  ;;;

        jnz     .send

        mov     ebx, [eax + TCP_SOCKET.max_sndwnd]

        shr     ebx, 1

        cmp     esi, ebx

        jae     .send

        mov     ebx, [eax + TCP_SOCKET.SND_NXT]

        cmp     ebx, [eax + TCP_SOCKET.SND_MAX]

        jb      .send

  .len_zero:

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

; Check if a window update should be sent (154)

        test    ecx, ecx

        jz      .no_window

        push    ecx

        mov     cl, [eax + TCP_SOCKET.RCV_SCALE]

        inc     cl                                      ; we want it *2

        mov     ebx, TCP_max_win

        shl     ebx, cl

        pop     ecx

        cmp     ebx, ecx

        cmovb   ebx, ecx

        ; now ebx is TWICE the amount we can increase the window

        ; (with TCP_max_win shl rcv_scale as the maximum)

        cmp     ebx, [eax + TCP_SOCKET.t_maxseg]

        jae     .send

  ;;;      cmp     ebx, [eax + ]                        ;;; TODO: check receive buffer high water mark

    ;;;    jae     .send

  .no_window:

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

; Should a segment be sent? (174)

        test    [eax + TCP_SOCKET.t_flags], TF_ACKNOW   ; we need to ACK

        jnz     .send

        test    dl, TH_SYN + TH_RST                     ; we need to send a SYN or RST

        jnz     .send

        mov     ebx, [eax + TCP_SOCKET.SND_UP]          ; when urgent pointer is beyond start of send bufer

        cmp     ebx, [eax + TCP_SOCKET.SND_UNA]

        ja      .send

        test    dl, TH_FIN

        jz      .enter_persist  ; no reason to send, enter persist state

; FIN was set, only send if not already sent, or on retransmit

        test    [eax + TCP_SOCKET.t_flags], TF_SENTFIN

        jnz     .send

        mov     ebx, [eax + TCP_SOCKET.SND_NXT]

        cmp     ebx, [eax + TCP_SOCKET.SND_UNA]

        je      .send

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

; Enter persist state (191)

  .enter_persist:

        cmp     [eax + STREAM_SOCKET.snd.size], 0       ; Data ready to send?

        jne     @f

        cmp     [eax + TCP_SOCKET.timer_retransmission], 0

        jne     @f

        cmp     [eax + TCP_SOCKET.timer_persist], 0     ; Persist timer already expired?

        jne     @f

        DEBUGF  1,"Entering persist state\n"

        mov     [eax + TCP_SOCKET.t_rxtshift], 0

        TCP_set_persist eax

       @@:

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

; No reason to send a segment (219)

        DEBUGF  1,"No reason to send a segment\n"

        pusha

        lea     ecx, [eax + SOCKET.mutex]

        call    mutex_unlock

        popa

        ret

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

;

; Send a segment (222)

;

; eax = socket pointer

; esi = data len

;  dl = flags

;

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

  .send:

        DEBUGF  1,"Preparing to send a segment\n"

        mov     edi, sizeof.TCP_header  ; edi will contain headersize

        sub     esp, 8                  ; create some space on stack

        push    eax                     ; save socket pointer

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

; Send options with first SYN segment

        test    dl, TH_SYN

        jz      .options_done

        push    [eax + TCP_SOCKET.ISS]

        pop     [eax + TCP_SOCKET.SND_NXT]

        test    [eax + TCP_SOCKET.t_flags], TF_NOOPT

        jnz     .options_done

        mov     ecx, 1460                              ;;;; FIXME

        or      ecx, TCP_OPT_MAXSEG shl 24 + 4 shl 16

        bswap   ecx

        push    ecx

        add     di, 4

        test    [eax + TCP_SOCKET.t_flags], TF_REQ_SCALE

        jz      .no_syn

        test    dl, TH_ACK

        jnz     .scale_opt

        test    [eax + TCP_SOCKET.t_flags], TF_RCVD_SCALE

        jz      .no_syn

  .scale_opt:

        movzx   ecx, byte [eax + TCP_SOCKET.request_r_scale]

        or      ecx, TCP_OPT_WINDOW shl 24 + 4 shl 16 + TCP_OPT_NOP shl 8

        bswap   ecx

        pushd   ecx

        add     di, 4

  .no_syn:

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

; Make the timestamp option if needed

        test    [eax + TCP_SOCKET.t_flags], TF_REQ_TSTMP

        jz      .no_timestamp

        test    dl, TH_RST

        jnz     .no_timestamp

        test    dl, TH_ACK

        jz      .timestamp

        test    [eax + TCP_SOCKET.t_flags], TF_RCVD_TSTMP

        jz      .no_timestamp

  .timestamp:

        mov     ebx, [timer_ticks]

        bswap   ebx

        push    ebx

        pushw   0

        pushd   TCP_OPT_TIMESTAMP + 10 shl 8 + TCP_OPT_NOP shl 16 + TCP_OPT_NOP shl 24

        add     di, 10

  .no_timestamp:

        ; 

  .options_done:

; eax = socket ptr

; edx = flags

; edi = header size

; esi = data len

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

; check if we dont exceed the max segment size (270)

        add     esi, edi                        ; total TCP segment size

        cmp     esi, [eax + TCP_SOCKET.t_maxseg]

        jbe     .no_overflow

        mov     esi, [eax + TCP_SOCKET.t_maxseg]

;;; sendalot = 1

  .no_overflow:

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

; Start by pushing all TCP header values in reverse order on stack

; (essentially, creating the tcp header on the stack!)

        pushw   0       ;        .UrgentPointer          dw ?

        pushw   0       ;        .Checksum               dw ?

        pushw   0x00a0  ;        .Window                 dw ?    ;;;;;;; FIXME

        shl     edi, 2  ;        .DataOffset             db ?  only 4 left-most bits

        shl     dx, 8

        or      dx, di  ;        .Flags                  db ?

        pushw   dx

        shr     edi, 2  ;        .DataOffset             db ? ;;;;

        push    [eax + TCP_SOCKET.RCV_NXT]      ;        .AckNumber              dd ?

        ntohd   [esp]

        push    [eax + TCP_SOCKET.SND_NXT]      ;        .SequenceNumber         dd ?

        ntohd   [esp]

        push    [eax + TCP_SOCKET.RemotePort]   ;        .DestinationPort        dw ?

        ntohw   [esp]

        push    [eax + TCP_SOCKET.LocalPort]    ;        .SourcePort             dw ?

        ntohw   [esp]

        push    edi             ; header size

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

; Create the IP packet

        mov     ecx, esi

        mov     ebx, [eax + IP_SOCKET.LocalIP]  ; source ip

        mov     eax, [eax + IP_SOCKET.RemoteIP] ; dest ip

        mov     di, IP_PROTO_TCP shl 8 + 128

        call    IPv4_output

        jz      .ip_error

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

; Move TCP header from stack to TCP packet

        push    ecx

        mov     ecx, [esp+4]

        lea     esi, [esp+4+4]

        shr     ecx, 2

        rep     movsd

        pop     ecx             ; full TCP packet size

        pop     esi             ; headersize

        add     esp, esi

        mov     [esp + 4], eax          ; packet ptr

        mov     [esp + 4+4], edx        ; packet size

        mov     edx, edi                ; begin of data

        sub     edx, esi                ; begin of packet (edi = begin of data)

        push    ecx

        sub     ecx, esi                ; data size

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

; Copy the data

; eax = ptr to ring struct

; ecx = buffer size

; edi = ptr to buffer

        mov     eax, [esp+4]                    ; get socket ptr

        add     [eax + TCP_SOCKET.SND_NXT], ecx ; update sequence number

        add     eax, STREAM_SOCKET.snd

        push    edx

        call    SOCKET_ring_read

        pop     esi                             ; begin of data

        pop     ecx                             ; full packet size

        pop     eax                             ; socket ptr

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

; update sequence number and timers  (400)

        test    [esi + TCP_header.Flags], TH_SYN + TH_FIN

        jz      @f

        inc     [eax + TCP_SOCKET.SND_NXT]      ; syn and fin take a sequence number

        test    [esi + TCP_header.Flags], TH_FIN

        jz      @f

        or      [eax + TCP_SOCKET.t_flags], TF_SENTFIN  ; if we sent a fin, set the sentfin flag

       @@:

        mov     edx, [eax + TCP_SOCKET.SND_NXT]

        cmp     edx, [eax + TCP_SOCKET.SND_MAX]

        jbe     @f

        mov     [eax + TCP_SOCKET.SND_MAX], edx

        ;;;; TODO: time transmission (420)

       @@:

; set retransmission timer if not already set, and not doing an ACK or keepalive probe

        cmp     [eax + TCP_SOCKET.timer_retransmission], 1000 ;;;; FIXME

        jb      .retransmit_set

        cmp     edx, [eax + TCP_SOCKET.SND_UNA]         ; edx = [eax + TCP_SOCKET.SND_NXT]

        je      .retransmit_set

        mov     edx, [eax + TCP_SOCKET.t_rxtcur]

        mov     [eax + TCP_SOCKET.timer_retransmission], dx

        cmp     [eax + TCP_SOCKET.timer_persist], 0

        jne     @f

        mov     [eax + TCP_SOCKET.timer_persist], 0

        mov     [eax + TCP_SOCKET.t_rxtshift], 0

       @@:

  .retransmit_set:

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

; Create the checksum

        DEBUGF  1,"checksum: ptr=%x size=%u\n", esi, ecx

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

        mov     [esi + TCP_header.Checksum], dx

; unlock socket

        pusha

        lea     ecx, [eax + SOCKET.mutex]

        call    mutex_unlock

        popa

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

; Send the packet

        DEBUGF  1,"Sending TCP Packet to device %x\n", ebx

        call    [ebx + NET_DEVICE.transmit]

        ret

  .ip_error:

        pop     ecx

        add     esp, ecx

        pop     eax

        add     esp, 8

        pusha

        lea     ecx, [eax + SOCKET.mutex]

        call    mutex_unlock

        popa

        DEBUGF 1,"TCP_output: IP error\n"

        ret