WebSVN – Kolibri OS – Diff – /kernel/trunk/network/tcp_output.inc

 ;;          GNU GENERAL PUBLIC LICENSE                             ;;
 ;;             Version 2, June 1991                                ;;
 ;;                                                                 ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+$Revision: 6476 $
-$Revision: 6474 $
+TCP_BIT_SENDALOT        = 1 shl 0
 ;-----------------------------------------------------------------;
 ;                                                                 ;
   .not_idle:
   .again:
+        mov     [temp_bits], 0
-        mov     [temp_bits], 0
+; Calculate offset
+        mov     ebx, [eax + TCP_SOCKET.SND_NXT]
+        sub     ebx, [eax + TCP_SOCKET.SND_UNA]
-        mov     ebx, [eax + TCP_SOCKET.SND_NXT]         ; calculate offset (71)
-        sub     ebx, [eax + TCP_SOCKET.SND_UNA]         ;
+; Determine window
-        mov     ecx, [eax + TCP_SOCKET.SND_WND]         ; determine window
+        mov     ecx, [eax + TCP_SOCKET.SND_WND]
-        cmp     ecx, [eax + TCP_SOCKET.SND_CWND]        ;
+        cmp     ecx, [eax + TCP_SOCKET.SND_CWND]
+        jb      @f
+        mov     ecx, [eax + TCP_SOCKET.SND_CWND]
-        jb      @f                                      ;
+       @@:
         mov     ecx, [eax + TCP_SOCKET.SND_CWND]        ;
-       @@:                                              ;
+; get flags in dl
         mov     [eax + TCP_SOCKET.t_rxtshift], 0
   .no_force:
 ;--------------------------------
-; Calculate how much data to send (106)
+; Calculate how much data to send
         mov     esi, [eax + STREAM_SOCKET.snd.size]
         cmp     esi, ecx
         jb      @f
         mov     esi, ecx
        @@:
         sub     esi, ebx
 ;------------------------
-; check for window shrink (107)
+; check for window shrink
 ; If FIN has been sent, but not ACKed, but we havent been called to retransmit, esi will be -1
-; 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.
-; Otherwise, window shrank after we sent into it.
+        jae     .not_persist
-        jae     .not_persist
+; enter persist state
         xor     esi, esi
 ; enter persist state
+; If window shrank to 0
         xor     esi, esi
         test    ecx, ecx
-; If window shrank to 0
+        jnz     @f
         test    ecx, ecx
-        jnz     @f
+; cancel pending retransmit
-; cancel pending retransmit
+        and     [eax + TCP_SOCKET.timer_flags], not timer_flag_retransmission
         and     [eax + TCP_SOCKET.timer_flags], not timer_flag_retransmission
 ; pull SND_NXT back to (closed) window, We will enter persist state below.
 ; 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_persist:
 ;---------------------------
-; Send one segment at a time (124)
+; Send one segment at a time
         cmp     esi, [eax + TCP_SOCKET.t_maxseg]
         jbe     @f
         mov     esi, [eax + TCP_SOCKET.t_maxseg]
         or      [temp_bits], TCP_BIT_SENDALOT
        @@:
 ;--------------------------------------------
-; Turn of FIN flag if send buffer not emptied (128)
+; Turn of FIN flag if send buffer not emptied
         jb      .send
   .len_zero:
 ;----------------------------------------
-; Check if a window update should be sent (154)
+; Check if a window update should be sent
         mov     ebx, ecx
        @@:
         sub     ebx, [eax + TCP_SOCKET.RCV_ADV]
         add     ebx, [eax + TCP_SOCKET.RCV_NXT]
+        DEBUGF  DEBUG_NETWORK_VERBOSE, "TCP_output: we can increase window by %d bytes\n", ebx
         mov     edi, [eax + TCP_SOCKET.t_maxseg]
-        shl     edi, 1
         shl     edi, 1
         cmp     ebx, edi
         jae     .send
         shl     ebx, 1
 ;        cmp     ebx, [eax + TCP_SOCKET.]    ;;; TODO: check with receive buffer high water mark
 ;        jae     TCP_send
+  .no_window:
-  .no_window:
+;--------------------------
 ; Should a segment be sent?
 ;--------------------------
         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
-        ja      .send
+; Do we need to send a FIN according to our state?
         test    dl, TH_FIN
-        jz      .enter_persist  ; no reason to send, enter persist state
+        jz      .enter_persist                          ; no reason to send, enter persist state
+; Do so if we didnt do it already
-; FIN was set, only send if not already sent, or on retransmit
+        test    [eax + TCP_SOCKET.t_flags], TF_SENTFIN
         jz      .send
         test    [eax + TCP_SOCKET.t_flags], TF_SENTFIN
-        jz      .send
+; Or when we need to retransmit the FIN
         mov     ebx, [eax + TCP_SOCKET.SND_NXT]
         cmp     ebx, [eax + TCP_SOCKET.SND_UNA]
         je      .send
         mov     [eax + TCP_SOCKET.t_rxtshift], 0
         call    tcp_set_persist
        @@:
 ;----------------------------
-; No reason to send a segment (219)
+; No reason to send a segment
         DEBUGF  DEBUG_NETWORK_VERBOSE, "TCP_output: No reason to send a segment\n"
         ret
 ;-----------------------------------------------
+;
-; Send a segment (222)
+; Send a segment
+;
 ; eax = socket pointer
 ; esi = data len
 ; edx = flags
 ; edi = header size
 ; esi = data len
 ;---------------------------------------------
-; check if we dont exceed the max segment size (270)
+; check if we dont exceed the max segment size
         add     esi, edi                        ; total TCP segment size
         cmp     esi, [eax + TCP_SOCKET.t_maxseg]
         jbe     .no_overflow
         mov     esi, [eax + TCP_SOCKET.t_maxseg]
+        or      [temp_bits], TCP_BIT_SENDALOT
-        or      [temp_bits], TCP_BIT_SENDALOT
+  .no_overflow:
   .no_overflow:
 ; Update stats
 ; Update stats
 ;-----------------------------------------------------------------
 ; 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                               ; UrgentPointer
-        pushw   0       ;        .Checksum               dw ?
+        pushw   0                               ; Checksum
-        pushw   bx      ;        .Window                 dw ?
+        pushw   bx                              ; Window
-        shl     edi, 2  ;        .DataOffset             db ?  only 4 left-most bits
+        shl     edi, 2                          ; DataOffset
         shl     dx, 8
-        or      dx, di  ;        .Flags                  db ?
+        or      dx, di                          ; Flags
         pushw   dx
-        shr     edi, 2  ;        .DataOffset             db ?
+        shr     edi, 2                          ; DataOffset
-        push    [eax + TCP_SOCKET.RCV_NXT]      ;        .AckNumber              dd ?
+        push    [eax + TCP_SOCKET.RCV_NXT]      ; AckNumber
         ntohd   [esp]
-        push    [eax + TCP_SOCKET.SND_NXT]      ;        .SequenceNumber         dd ?
+        push    [eax + TCP_SOCKET.SND_NXT]      ; SequenceNumber
         ntohd   [esp]
         pop     edi
         pop     esi                             ; begin of data
         pop     ecx                             ; full packet size
         mov     eax, [esp + 8]                  ; socket ptr
-;----------------------------------
+;----------------------------
-; initialize retransmit timer (400)
+; initialize retransmit timer
 ;TODO: check t_force and persist
         mov     [eax + TCP_SOCKET.t_rtseq], edi
         inc     [TCPS_segstimed]
        @@:
+; set retransmission timer if not already set, and not doing an ACK or keepalive probe
 ; set retransmission timer if not already set, and not doing an ACK or keepalive probe
         test    [eax + TCP_SOCKET.timer_flags], timer_flag_retransmission
         jnz     .retransmit_set
         test    [eax + TCP_SOCKET.timer_flags], timer_flag_persist
         jz      .retransmit_set
         and     [eax + TCP_SOCKET.timer_flags], not timer_flag_persist
-        mov     [eax + TCP_SOCKET.t_rxtshift], 0
         mov     [eax + TCP_SOCKET.t_rxtshift], 0
   .retransmit_set:
         jbe     @f
         mov     [eax + TCP_SOCKET.RCV_ADV], ecx
        @@:
+; update last ack sent
 ; update last ack sent
         push    [eax + TCP_SOCKET.RCV_NXT]
         pop     [eax + TCP_SOCKET.last_ack_sent]
 ; clear the ACK flags
 ; clear the ACK flags
         and     [eax + TCP_SOCKET.t_flags], not (TF_ACKNOW + TF_DELACK)

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(root)/kernel/trunk/network/tcp_output.inc – Rev 6474 → 6476