;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; ;; 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 ;; ;; ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; $Revision$ ;----------------------------------------------------------------- ; ; 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. jae .not_persist ; 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_persist: ;--------------------------- ; 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 socket: %x length: %u flags: %x\n", eax, esi, dl 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 mov [eax + TCP_SOCKET.timer_retransmission], TCP_time_re_min pusha lea ecx, [eax + SOCKET.mutex] call mutex_unlock popa DEBUGF 1,"TCP_output: IP error\n" ret