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/kernel/trunk/network/tcp_subr.inc
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; 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: 3514 $
 
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
call SOCKET_free
 
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=%x\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/4 shl 4)
stosb
mov al, cl
stosb
mov ax, 1280
rol ax, 8
stosw ; window
xor eax, eax
stosd ; checksum + urgentpointer
 
;---------------------
; Fill in the 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:
 
DEBUGF 1,"TCP_set_persist\n"
 
; First, check if retransmit timer is not set, retransmit and persist are mutually exclusive
 
cmp [eax + TCP_SOCKET.timer_retransmission], 0
ja @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
 
 
 
 
; ebx = socket ptr
; edx = segment ptr
align 4
TCP_reassemble:
 
 
 
ret
 
Property changes:
Added: svn:eol-style
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