;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; ;; Copyright (C) KolibriOS team 2004-2024. 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 ;; ;; ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; TCP_BIT_SENDALOT = 1 shl 0 ;-----------------------------------------------------------------; ; ; ; tcp_output ; ; ; ; IN: eax = socket pointer ; ; ; ; OUT: eax = 0 on success/errorcode ; ; ; ;-----------------------------------------------------------------; align 4 proc tcp_output locals temp_bits db ? rcv_window dd ? endl DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_output: socket=%x state=%u\n", eax, [eax + TCP_SOCKET.t_state] push eax lea ecx, [eax + SOCKET.mutex] call mutex_lock pop eax DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_output: socket locked\n" ; 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] jbe .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 [temp_bits], 0 ; Calculate offset mov ebx, [eax + TCP_SOCKET.SND_NXT] sub ebx, [eax + TCP_SOCKET.SND_UNA] ; Determine window mov ecx, [eax + TCP_SOCKET.SND_WND] cmp ecx, [eax + TCP_SOCKET.SND_CWND] jb @f mov ecx, [eax + TCP_SOCKET.SND_CWND] @@: ; get flags in dl call tcp_outflags ;------------------------ ; 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_flags], TF_FORCE jz .no_force DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_output: forcing data out\n" test ecx, ecx jnz .no_zero_window cmp ebx, [eax + STREAM_SOCKET.snd.size] jae @f and dl, not (TH_FIN) @@: inc ecx jmp .no_force .no_zero_window: and [eax + TCP_SOCKET.timer_flags], not timer_flag_persist mov [eax + TCP_SOCKET.t_rxtshift], 0 .no_force: ;-------------------------------- ; 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 ; If FIN has been sent, but not ACKed, but we havent been called to retransmit, esi will be -1 ; Otherwise, window shrank after we sent into it. jge .not_persist ; enter persist state xor esi, esi ; If window shrank to 0 test ecx, ecx jnz @f ; cancel pending retransmit and [eax + TCP_SOCKET.timer_flags], not timer_flag_retransmission ; 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 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 mov edi, [eax + TCP_SOCKET.SND_NXT] add edi, esi sub edi, [eax + TCP_SOCKET.SND_UNA] cmp edi, [eax + STREAM_SOCKET.snd.size] jae @f and dl, not (TH_FIN) @@: ;------------------------------- ; calculate window advertisement xor ecx, ecx test [eax + SOCKET.state], SS_CANTRCVMORE jnz @f mov ecx, SOCKET_BUFFER_SIZE sub ecx, [eax + STREAM_SOCKET.rcv.size] @@: ;------------------------------ ; Sender silly window avoidance test esi, esi jz .len_zero cmp esi, [eax + TCP_SOCKET.t_maxseg] je .send add ebx, esi ; offset + length cmp ebx, [eax + STREAM_SOCKET.snd.size] jb @f test [eax + TCP_SOCKET.t_flags], TF_NODELAY jnz .send mov ebx, [eax + TCP_SOCKET.SND_MAX] cmp ebx, [eax + TCP_SOCKET.SND_UNA] je .send @@: test [eax + TCP_SOCKET.t_flags], TF_FORCE 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 DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_output: window=%d\n", ecx ; Compare available window to amount of window known to peer (as advertised window less next expected input) ; If the difference is at least two max size segments, or at least 50% of the maximum possible window, ; Then we want to send a window update to the peer. test ecx, ecx jz .no_window push ecx mov cl, [eax + TCP_SOCKET.RCV_SCALE] mov ebx, TCP_max_win shl ebx, cl pop ecx sub ebx, [eax + TCP_SOCKET.RCV_ADV] add ebx, [eax + TCP_SOCKET.RCV_NXT] cmp ebx, ecx jl @f mov ebx, ecx @@: 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 cmp ebx, edi jae .send cmp ebx, SOCKET_BUFFER_SIZE/2 jae .send .no_window: ;-------------------------- ; Should a segment be sent? DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_output: Should a segment be sent?\n" 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 ; 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 ; Do so if we didnt do it already 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 ;-------------------- ; Enter persist state .enter_persist: cmp [eax + STREAM_SOCKET.snd.size], 0 ; Data ready to send? je @f test [eax + TCP_SOCKET.timer_flags], timer_flag_retransmission or timer_flag_persist jnz @f DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_output: Entering persist state\n" mov [eax + TCP_SOCKET.t_rxtshift], 0 call tcp_set_persist @@: ;---------------------------- ; No reason to send a segment DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_output: No reason to send a segment\n" pusha lea ecx, [eax + SOCKET.mutex] call mutex_unlock popa xor eax, eax ret ;----------------------------------------------- ; ; Send a segment ; ; eax = socket pointer ; esi = data len ; dl = flags ; ;----------------------------------------------- .send: DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: socket=%x length=%u flags=%x\n", eax, esi, dl push eax ; save socket ptr push esi ; and data length too mov edi, sizeof.TCP_header ; edi will contain headersize ;------------------------------------ ; 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: use routing blablabla to determine MSS or ecx, TCP_OPT_MAXSEG shl 24 + 4 shl 16 bswap ecx push ecx add di, 4 DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: added maxseg option\n" test [eax + TCP_SOCKET.t_flags], TF_REQ_SCALE jz .no_scale test dl, TH_ACK jz .scale_opt test [eax + TCP_SOCKET.t_flags], TF_RCVD_SCALE jz .no_scale .scale_opt: mov cl, [eax + TCP_SOCKET.request_r_scale] mov ch, TCP_OPT_NOP pushw cx pushw TCP_OPT_WINDOW + 3 shl 8 add di, 4 DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: added scale option\n" .no_scale: .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: pushd 0 pushd [timer_ticks] pushd TCP_OPT_NOP + TCP_OPT_NOP shl 8 + TCP_OPT_TIMESTAMP shl 16 + 10 shl 24 add di, 12 DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: added timestamp\n" .no_timestamp: ; .options_done: ; eax = socket ptr ; edx = flags ; edi = header size ; esi = data len ;--------------------------------------------- ; check if we don't 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 .no_overflow: ; Update stats test esi, esi jz .zero_data test [eax + TCP_SOCKET.t_flags], TF_FORCE jz @f cmp esi, 1 jne @f inc [TCPS_sndprobe] jmp .eos @@: mov ebx, [eax + TCP_SOCKET.SND_NXT] cmp ebx, [eax + TCP_SOCKET.SND_MAX] jae @f inc [TCPS_sndrexmitpack] add [TCPS_sndrexmitbyte], esi jmp .eos @@: inc [TCPS_sndpack] add [TCPS_sndbyte], esi jmp .eos .zero_data: test [eax + TCP_SOCKET.t_flags], TF_ACKNOW jz @f inc [TCPS_sndacks] jmp .eos @@: test dl, TH_SYN + TH_FIN + TH_RST jz @f inc [TCPS_sndctrl] jmp .eos @@: mov ebx, [eax + TCP_SOCKET.SND_UP] cmp ebx, [eax + TCP_SOCKET.SND_UNA] jb @f inc [TCPS_sndurg] jmp .eos @@: inc [TCPS_sndwinup] .eos: ;--------------------------------------------------- ; Don't increase sequence number when resending a FIN test dl, TH_FIN jz .no_fin_retransmit test [eax + TCP_SOCKET.t_flags], TF_SENTFIN jz .no_fin_retransmit mov ebx, [eax + TCP_SOCKET.SND_NXT] cmp ebx, [eax + TCP_SOCKET.SND_MAX] jne .no_fin_retransmit dec [eax + TCP_SOCKET.SND_NXT] .no_fin_retransmit: ;---------------------------------------------------- ; Calculate the receive window. ; Don't shrink window, but avoid silly window syndrome xor ebx, ebx test [eax + SOCKET.state], SS_CANTRCVMORE jnz @f mov ebx, SOCKET_BUFFER_SIZE sub ebx, [eax + STREAM_SOCKET.rcv.size] cmp ebx, SOCKET_BUFFER_SIZE/4 jge @f cmp ebx, [eax + TCP_SOCKET.t_maxseg] jge @f xor ebx, ebx @@: mov cl, [eax + TCP_SOCKET.RCV_SCALE] push eax mov eax, TCP_max_win shl eax, cl cmp ebx, eax jle @f mov ebx, eax @@: pop eax mov ecx, [eax + TCP_SOCKET.RCV_ADV] sub ecx, [eax + TCP_SOCKET.RCV_NXT] cmp ebx, ecx jg @f mov ebx, ecx @@: ;; TODO URGENT POINTER DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: window=%u\n", ebx mov [rcv_window], ebx mov cl, [eax + TCP_SOCKET.RCV_SCALE] shr ebx, cl xchg bl, bh ;----------------------------------------------------------------- ; Start by pushing all TCP header values in reverse order on stack ; (essentially, creating the tcp header on the stack!) pushw 0 ; UrgentPointer pushw 0 ; Checksum pushw bx ; Window shl edi, 2 ; DataOffset shl dx, 8 or dx, di ; Flags pushw dx shr edi, 2 ; DataOffset push [eax + TCP_SOCKET.RCV_NXT] ; AckNumber ntohd [esp] push [eax + TCP_SOCKET.SND_NXT] ; SequenceNumber ntohd [esp] push [eax + TCP_SOCKET.RemotePort] ; DestinationPort push [eax + TCP_SOCKET.LocalPort] ; SourcePort push edi ; header size ;--------------------- ; Create the IP packet mov ecx, esi mov ebx, [eax + IP_SOCKET.device] mov edx, [eax + IP_SOCKET.LocalIP] ; source ip mov edi, [eax + IP_SOCKET.RemoteIP] ; dest ip mov al, [eax + IP_SOCKET.ttl] mov ah, IP_PROTO_TCP call ipv4_output jz .ip_error ;------------------------------------------ ; Move TCP header from stack to TCP segment push ecx mov ecx, [esp + 4] lea esi, [esp + 8] shr ecx, 2 ; count is in bytes, we will work with dwords rep movsd pop ecx ; full TCP packet size pop esi ; headersize add esp, esi ; remove it from stack push eax ; packet ptr for send proc 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 + 12] ; get socket ptr push edx push [eax + TCP_SOCKET.SND_NXT] ; we'll need this for timing the transmission test ecx, ecx jz .nodata mov edx, [eax + TCP_SOCKET.SND_NXT] add [eax + TCP_SOCKET.SND_NXT], ecx ; update sequence number sub edx, [eax + TCP_SOCKET.SND_UNA] ; offset add eax, STREAM_SOCKET.snd call socket_ring_read .nodata: pop edi pop esi ; begin of data pop ecx ; full packet size mov eax, [esp + 8] ; socket ptr ;---------------------------- ; initialize retransmit timer ;TODO: check t_force and persist test [esi + TCP_header.Flags], TH_SYN + TH_FIN ; syn and fin take a sequence number jz @f inc [eax + TCP_SOCKET.SND_NXT] 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] ; is this a retransmission? jbe @f mov [eax + TCP_SOCKET.SND_MAX], edx ; [eax + TCP_SOCKET.SND_NXT] from before we updated it cmp [eax + TCP_SOCKET.t_rtt], 0 ; are we currently timing anything? je @f mov [eax + TCP_SOCKET.t_rtt], 1 ; nope, start transmission timer 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 test [eax + TCP_SOCKET.timer_flags], timer_flag_retransmission jnz .retransmit_set cmp edx, [eax + TCP_SOCKET.SND_UNA] ; edx is still [eax + TCP_SOCKET.SND_NXT] je .retransmit_set mov edx, [eax + TCP_SOCKET.t_rxtcur] mov [eax + TCP_SOCKET.timer_retransmission], edx or [eax + TCP_SOCKET.timer_flags], timer_flag_retransmission 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 .retransmit_set: ;-------------------- ; Create the checksum xor dx, dx test [ebx + NET_DEVICE.hwacc], NET_HWACC_TCP_IPv4_OUT jnz .checksum_ok tcp_checksum (eax + IP_SOCKET.LocalIP), (eax + IP_SOCKET.RemoteIP) .checksum_ok: mov [esi + TCP_header.Checksum], dx ;---------------- ; Send the packet DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: Sending with device %x\n", ebx call [ebx + NET_DEVICE.transmit] jnz .send_error ;--------------- ; Ok, data sent! pop ecx pop eax call net_ptr_to_num4 inc [TCP_segments_tx + edi] inc [TCPS_sndtotal] ; update advertised receive window mov ecx, [rcv_window] test ecx, ecx jz @f add ecx, [eax + TCP_SOCKET.RCV_NXT] cmp ecx, [eax + TCP_SOCKET.RCV_ADV] jbe @f mov [eax + TCP_SOCKET.RCV_ADV], ecx @@: ; update last ack sent push [eax + TCP_SOCKET.RCV_NXT] pop [eax + TCP_SOCKET.last_ack_sent] ; clear the ACK flags and [eax + TCP_SOCKET.t_flags], not (TF_ACKNOW + TF_DELACK) ;-------------- ; unlock socket DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: unlocking socket 0x%x\n", eax push eax lea ecx, [eax + SOCKET.mutex] call mutex_unlock pop eax ;----------------------------- ; Check if we need more output test [temp_bits], TCP_BIT_SENDALOT jnz tcp_output.again DEBUGF DEBUG_NETWORK_VERBOSE, "TCP_send: success!\n" xor eax, eax ret .ip_error: pop ecx add esp, ecx add esp, 4 pop eax mov [eax + TCP_SOCKET.timer_retransmission], TCP_time_re_min or [eax + TCP_SOCKET.timer_flags], timer_flag_retransmission lea ecx, [eax + SOCKET.mutex] call mutex_unlock DEBUGF DEBUG_NETWORK_ERROR, "TCP_send: IP error\n" or eax, -1 ret .send_error: add esp, 4 pop eax lea ecx, [eax + SOCKET.mutex] call mutex_unlock DEBUGF DEBUG_NETWORK_ERROR, "TCP_send: sending failed\n" or eax, -2 ret endp