;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2010. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;; TCP.INC ;;
;; ;;
;; 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: 1530 $
; Socket states
TCB_CLOSED equ 0
TCB_LISTEN equ 1
TCB_SYN_SENT equ 2
TCB_SYN_RECEIVED equ 3
TCB_ESTABLISHED equ 4
TCB_CLOSE_WAIT equ 5
TCB_FIN_WAIT_1 equ 6
TCB_CLOSING equ 7
TCB_LAST_ACK equ 8
TCB_FIN_WAIT_2 equ 9
TCB_TIMED_WAIT equ 10
; Socket Flags
TF_ACKNOW equ 1 shl 0 ; ack peer immediately
TF_DELACK equ 1 shl 1 ; ack, but try to delay it
TF_NODELAY equ 1 shl 2 ; don't delay packets to coalesce
TF_NOOPT equ 1 shl 3 ; don't use tcp options
TF_SENTFIN equ 1 shl 4 ; have sent FIN
TF_REQ_SCALE equ 1 shl 5 ; have/will request window scaling
TF_RCVD_SCALE equ 1 shl 6 ; other side has requested scaling
TF_REQ_TSTMP equ 1 shl 7 ; have/will request timestamps
TF_RCVD_TSTMP equ 1 shl 8 ; a timestamp was received in SYN
TF_SACK_PERMIT equ 1 shl 9 ; other side said I could SACK
; Segment flags
TH_FIN equ 1 shl 0
TH_SYN equ 1 shl 1
TH_RST equ 1 shl 2
TH_PUSH equ 1 shl 3
TH_ACK equ 1 shl 4
TH_URG equ 1 shl 5
; Segment header options
TCP_OPT_EOL equ 0 ; End of option list.
TCP_OPT_NOP equ 1 ; No-Operation.
TCP_OPT_MAXSEG equ 2 ; Maximum Segment Size.
TCP_OPT_WINDOW equ 3 ; window scale
TCP_OPT_TIMESTAMP equ 8
; Fundamental timer values
TCP_time_MSL equ 47 ; max segment lifetime (30s)
TCP_time_re_min equ 2 ; min retransmission (1,28s)
TCP_time_re_max equ 100 ; max retransmission (64s)
TCP_time_pers_min equ 8 ; min persist (5,12s)
TCP_time_pers_max equ 94 ; max persist (60,16s)
TCP_time_keep_init equ 118 ; connectione stablishment (75,52s)
TCP_time_keep_idle equ 4608 ; idle time before 1st probe (2h)
TCP_time_keep_interval equ 118 ; between probes when no response (75,52s)
TCP_time_rtt_default equ 5 ; default Round Trip Time (3,2s)
; timer constants
TCP_max_rxtshift equ 12 ; max retransmissions waiting for ACK
TCP_max_keepcnt equ 8 ; max keepalive probes
;
TCP_max_winshift equ 14
TCP_max_win equ 65535
struct TCP_segment
.SourcePort dw ?
.DestinationPort dw ?
.SequenceNumber dd ?
.AckNumber dd ?
.DataOffset db ? ; DataOffset[0-3 bits] and Reserved[4-7]
.Flags db ? ; Reserved[0-1 bits]|URG|ACK|PSH|RST|SYN|FIN
.Window dw ?
.Checksum dw ?
.UrgentPointer dw ?
.Data: ; ..or options
ends
struct tcp_in_queue_entry
.data_ptr dd ?
.data_size dd ?
.offset dd ?
.size:
ends
struct tcp_out_queue_entry
.data_ptr dd ?
.data_size dd ?
.size:
ends
align 4
uglobal
TCP_segments_tx rd IP_MAX_INTERFACES
TCP_segments_rx rd IP_MAX_INTERFACES
TCP_bytes_rx rq IP_MAX_INTERFACES
TCP_bytes_tx rq IP_MAX_INTERFACES
TCP_sequence_num dd ?
endg
;-----------------------------------------------------------------
;
; TCP_init
;
; This function resets all TCP variables
;
;-----------------------------------------------------------------
macro TCP_init {
xor eax, eax
mov edi, TCP_segments_tx
mov ecx, (6*IP_MAX_INTERFACES)
rep stosd
pseudo_random eax
mov [TCP_sequence_num], eax
}
;----------------------
;
;
;----------------------
macro TCP_timer_160ms {
local .loop
local .exit
mov eax, net_sockets
.loop:
mov eax, [eax + SOCKET.NextPtr]
or eax, eax
jz .exit
cmp [eax + SOCKET.Type], IP_PROTO_TCP
jne .loop
dec [eax + TCP_SOCKET.timer_ack]
jnz .loop
DEBUGF 1,"TCP ack for socket %x expired, time to piggyback!\n", eax
push eax
call TCP_respond_socket
pop eax
jmp .loop
.exit:
}
;-----------------------------------------------------------------
;
;
;-----------------------------------------------------------------
macro TCP_timer_640ms {
local .loop
local .exit
; Update TCP sequence number
add [TCP_sequence_num], 64000
; scan through all the active TCP sockets, decrementing ALL timers
; timers do not have the chance to wrap because of the keepalive timer will kill the socket when it expires
mov eax, net_sockets
.loop:
mov eax, [eax + SOCKET.NextPtr]
.check_only:
or eax, eax
jz .exit
cmp [eax + SOCKET.Type], IP_PROTO_TCP
jne .loop
inc [eax + TCP_SOCKET.t_idle]
dec [eax + TCP_SOCKET.timer_retransmission]
jnz .check_more2
DEBUGF 1,"socket %x: Retransmission timer expired\n", eax
push eax
call TCP_output
pop eax
.check_more2:
dec [eax + TCP_SOCKET.timer_keepalive]
jnz .check_more3
DEBUGF 1,"socket %x: Keepalive expired\n", eax
;;; TODO: check socket state and handle accordingly
.check_more3:
dec [eax + TCP_SOCKET.timer_timed_wait]
jnz .check_more5
DEBUGF 1,"socket %x: 2MSL timer expired\n", eax
.check_more5:
dec [eax + TCP_SOCKET.timer_persist]
jnz .loop
DEBUGF 1,"socket %x: persist timer expired\n", eax
jmp .loop
.exit:
}
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
;---------------------
; Real header and data
push esi
call checksum_1
call checksum_2
pop esi
} ; returns in dx only
;-----------------------------------------------------------------
;
; TCP_input:
;
; IN: [esp] = ptr to buffer
; [esp+4] = buffer size
; ebx = ptr to device struct
; ecx = segment size
; edx = ptr to TCP segment
;
; esi = ipv4 source address
; edi = ipv4 dest address
;
; OUT: /
;
;-----------------------------------------------------------------
align 4
TCP_input:
DEBUGF 1,"TCP_input size=%u\n", ecx
; Offset must be greater than or equal to the size of the standard TCP header (20) and less than or equal to the TCP length.
movzx eax, [edx + TCP_segment.DataOffset]
and eax, 0xf0
shr al, 2
DEBUGF 1,"headersize=%u\n", eax
cmp eax, 20
jl .drop
;-------------------------------
; Now, re-calculate the checksum
push eax ecx edx
pushw [edx + TCP_segment.Checksum]
mov [edx + TCP_segment.Checksum], 0
push esi edi
mov esi, edx
TCP_checksum (esp), (esp+4)
pop esi edi ; yes, swap them (we dont need dest addr)
pop cx ; previous checksum
cmp cx, dx
pop edx ecx esi
jnz .drop
DEBUGF 1,"Checksum is correct\n"
sub ecx, esi ; update packet size
jl .drop
;-----------------------------------------------------------------------------------------
; Check if this packet has a timestamp option (We do it here so we can process it quickly)
cmp esi, 20 + 12 ; Timestamp option is 12 bytes
jl .no_timestamp
je .is_ok
cmp byte [edx + TCP_segment.Data + 12], TCP_OPT_EOL ; end of option list
jne .no_timestamp
.is_ok:
test [edx + TCP_segment.Flags], TH_SYN ; SYN flag must not be set
jnz .no_timestamp
cmp dword [edx + TCP_segment.Data], 0x0101080a ; Timestamp header
jne .no_timestamp
DEBUGF 1,"timestamp ok\n"
; TODO: Parse the option
; TODO: Set a Bit in the TCP to tell all options are parsed
.no_timestamp:
;-------------------------------------------
; Convert Big-endian values to little endian
ntohld [edx + TCP_segment.SequenceNumber]
ntohld [edx + TCP_segment.AckNumber]
ntohlw [edx + TCP_segment.Window]
ntohlw [edx + TCP_segment.UrgentPointer]
ntohlw [edx + TCP_segment.SourcePort]
ntohlw [edx + TCP_segment.DestinationPort]
;------------------------------------------------------------
; Next thing to do is find the TCB (thus, the socket pointer)
; IP Packet TCP Destination Port = local Port
; (IP Packet SenderAddress = Remote IP) OR (Remote IP = 0)
; (IP Packet TCP Source Port = remote Port) OR (remote Port = 0)
mov ebx, net_sockets
.socket_loop:
mov ebx, [ebx + SOCKET.NextPtr]
or ebx, ebx
jz .drop_with_reset
cmp [ebx + SOCKET.Type], IP_PROTO_TCP
jne .socket_loop
mov ax, [edx + TCP_segment.DestinationPort]
cmp [ebx + TCP_SOCKET.LocalPort], ax
jne .socket_loop
mov eax, [ebx + IP_SOCKET.RemoteIP]
cmp eax, edi ; sender IP
je @f
test eax, eax
jnz .socket_loop
@@:
mov ax, [ebx + TCP_SOCKET.RemotePort]
cmp [edx + TCP_segment.SourcePort] , ax
je .found_socket
test ax, ax
jnz .socket_loop
.found_socket:
DEBUGF 1,"Socket ptr: %x\n", ebx
; ebx now contains the pointer to the socket
;----------------------------
; Check if socket isnt closed
cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSED
je .drop
;----------------
; Lock the socket
;; add ebx, SOCKET.lock ; TODO: figure out if we should lock now already
;; call wait_mutex
;; sub ebx, SOCKET.lock
DEBUGF 1,"Socket locked\n"
;----------------------------------------------------------------------------------------
; unscale the window into a 32 bit value (notice that SND_SCALE must be initialised to 0)
movzx eax, [edx + TCP_segment.Window]
push cx
mov cl, [ebx + TCP_SOCKET.SND_SCALE]
shl eax, cl
pop cx
;;;; do something with eax
;-----------------------------------
; Is this socket a listening socket?
; test [ebx + SOCKET.options], SO_ACCEPTCON
; jnz .listening_socket ;;;;; TODO
;-------------------------------------
; Reset idle timer and keepalive timer
mov [ebx + TCP_SOCKET.t_idle], 0
mov [ebx + TCP_SOCKET.timer_keepalive], TCP_time_keep_interval
;--------------------
; Process TCP options
cmp esi, 20 ; esi is headersize
je .no_options
DEBUGF 1,"Segment has options\n"
cmp [ebx + TCP_SOCKET.t_state], TCB_LISTEN ; no options when in listen state
jz .no_options
lea edi, [edx + TCP_segment.Data]
lea eax, [edx + esi]
.opt_loop:
cmp edi, eax
jge .no_options
cmp byte [edi], TCP_OPT_EOL ; end of option list?
jz .no_options
cmp byte [edi], TCP_OPT_NOP ; nop ?
jz .opt_nop
cmp byte [edi], TCP_OPT_MAXSEG
je .opt_maxseg
cmp byte [edi], TCP_OPT_WINDOW
je .opt_window
cmp byte [edi], TCP_OPT_TIMESTAMP
je .opt_timestamp
jmp .no_options ; If we reach here, some unknown options were received, skip them all!
.opt_nop:
inc edi
jmp .opt_loop
.opt_maxseg:
cmp byte [edi+1], 4
jne .no_options ; error occured, ignore all options!
test [edx + TCP_segment.Flags], TH_SYN
jz @f
movzx eax, word[edi+2]
rol ax, 8
DEBUGF 1,"Maxseg: %u", ax
mov [ebx + TCP_SOCKET.t_maxseg], eax
@@:
add edi, 4
jmp .opt_loop
.opt_window:
cmp byte [edi+1], 3
jne .no_options
test [edx + TCP_segment.Flags], TH_SYN
jz @f
DEBUGF 1,"Got window option"
;;;;;
@@:
add edi, 3
jmp .opt_loop
.opt_timestamp:
cmp byte [edi+1], 10
jne .no_options
DEBUGF 1,"Got timestamp option"
;;;;;
add edi, 10
jmp .opt_loop
.no_options:
;-----------------------------------------------------------------------
; Time to do some header prediction (Original Principle by Van Jacobson)
; There are two common cases for an uni-directional data transfer.
;
; General rule: the packets has no control flags, is in-sequence,
; window width didnt change and we're not retransmitting.
;
; Second rules:
; - If the length is 0 and the ACK moved forward, we're the sender side of the transfer.
; In this case we'll free the ACK'ed data and notify higher levels that we have free space in buffer
;
; - If the length is not 0 and the ACK didn't move, we're the receiver side of the transfer.
; If the packets are in order (data queue is empty), add the data to the socket buffer and request a delayed ACK
cmp [ebx + TCP_SOCKET.t_state], TCB_ESTABLISHED
jnz .not_uni_xfer
test [edx + TCP_segment.Flags], TH_SYN + TH_FIN + TH_RST + TH_URG
jnz .not_uni_xfer
test [edx + TCP_segment.Flags], TH_ACK
jz .not_uni_xfer
mov eax, [edx + TCP_segment.SequenceNumber]
cmp eax, [ebx + TCP_SOCKET.RCV_NXT]
jne .not_uni_xfer
movzx eax, [edx + TCP_segment.Window] ;;;;; (should use pre-calculated value isntead: todo: figure out where to store it)
cmp eax, [ebx + TCP_SOCKET.SND_WND]
jne .not_uni_xfer
mov eax, [ebx + TCP_SOCKET.SND_NXT]
cmp eax, [ebx + TCP_SOCKET.SND_MAX]
jne .not_uni_xfer
;---------------------------------------
; check if we are sender in the uni-xfer
; If the following 4 conditions are all true, this segment is a pure ACK.
;
; - The segment contains no data.
test ecx, ecx
jnz .not_sender
; - The congestion window is greater than or equal to the current send window.
; This test is true only if the window is fully open, that is, the connection is not in the middle of slow start or congestion avoidance.
mov eax, [ebx + TCP_SOCKET.SND_CWND]
cmp eax, [ebx + TCP_SOCKET.SND_WND]
jl .not_uni_xfer
; - The acknowledgment field in the segment is less than or equal to the maximum sequence number sent.
mov ecx, [edx + TCP_segment.AckNumber]
cmp ecx, [ebx + TCP_SOCKET.SND_MAX]
jg .not_uni_xfer
; - The acknowledgment field in the segment is greater than the largest unacknowledged sequence number.
sub ecx, [ebx + TCP_SOCKET.SND_UNA]
jle .not_uni_xfer
DEBUGF 1,"Header prediction: we are sender\n"
;---------------------------------
; Packet is a pure ACK, process it
; Update RTT estimators
; Delete acknowledged bytes from send buffer
; notice how ecx already holds number of bytes ack-ed
lea eax, [ebx + snd]
call SOCKET_ring_free
; Stop retransmit timer
mov [ebx + TCP_SOCKET.timer_ack], 0
; Awaken waiting processes
mov eax, ebx
call SOCKET_notify_owner
; Generate more output
call TCP_output
jmp .drop
;-------------------------------------------------
; maybe we are the receiver in the uni-xfer then..
.not_sender:
; - The amount of data in the segment is greater than 0 (data count is in ecx)
; - The acknowledgment field equals the largest unacknowledged sequence number. This means no data is acknowledged by this segment.
mov eax, [edx + TCP_segment.AckNumber]
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
jne .not_uni_xfer
; - The reassembly list of out-of-order segments for the connection is empty (seg_next equals tp). ;;;;;;;
jnz .not_uni_xfer
;-------------------------------------
; Complete processing of received data
DEBUGF 1,"header prediction: we are receiver\nreceiving %u bytes of data\n", ecx
add esi, edx
lea eax, [ebx + rcv]
call SOCKET_ring_add ; Add the data to the socket buffer
add [ebx + TCP_SOCKET.RCV_NXT], ecx ; Update sequence number with number of bytes we have copied
or [ebx + TCP_SOCKET.t_flags], TF_DELACK ; Set delayed ack flag
jmp .drop
;----------------------------------------------------
; Header prediction failed, doing it the slow way.. ;;;;; current implementation of header prediction destroys some regs (ecx) !!
.not_uni_xfer:
DEBUGF 1,"Header prediction failed\n"
;------------------------------
; Calculate receive window size
;;;;
;-------------------------
; TCP slow input procedure
DEBUGF 1,"TCP slow input procedure\n"
cmp [ebx + TCP_SOCKET.t_state], TCB_LISTEN
je .LISTEN
cmp [ebx + TCP_SOCKET.t_state], TCB_SYN_SENT
je .SYN_SENT
;--------------------------------------------
; Protection Against Wrapped Sequence Numbers
; First, check timestamp if present
;;;; TODO
; Then, check if at least some bytes of data are within window
;;;; TODO
jmp .trim_then_step6
;-------------
; Passive Open
align 4
.LISTEN:
DEBUGF 1,"TCP state: listen\n"
test [edx + TCP_segment.Flags], TH_RST
jnz .drop
test [edx + TCP_segment.Flags], TH_ACK
jnz .drop_with_reset
test [edx + TCP_segment.Flags], TH_SYN
jz .drop
; TODO: find sender ip address somewhere!
; TODO: check if it's a broadcast or multicast, and drop if so
call SOCKET_fork
jz .drop ; if we could not open a new connection, drop segment (;;;; should we send RST too?)
;-----------------------
; Fill in some variables
add [TCP_sequence_num], 64000
push [edx + TCP_segment.SourcePort]
pop [eax + TCP_SOCKET.RemotePort]
push [edx + TCP_segment.SequenceNumber]
pop [eax + TCP_SOCKET.IRS]
push [eax + TCP_SOCKET.ISS]
pop [eax + TCP_SOCKET.SND_NXT]
mov [eax + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
mov [eax + TCP_SOCKET.t_flags], TF_ACKNOW
mov [eax + TCP_SOCKET.timer_keepalive], TCP_time_keep_interval
mov ebx, eax
jmp .trim_then_step6
;------------
; Active Open
align 4
.SYN_SENT:
DEBUGF 1,"TCP state: syn_sent\n"
test [edx + TCP_segment.Flags], TH_ACK
jz @f
mov eax, [edx + TCP_segment.AckNumber]
cmp eax, [ebx + TCP_SOCKET.ISS]
jle .drop_with_reset
DEBUGF 1,"snd_max = %x\n", [ebx + TCP_SOCKET.SND_MAX] ;;; TODO: set this, but where?
; mov eax, [edx + TCP_segment.AckNumber]
;; cmp eax, [ebx + TCP_SOCKET.SND_MAX]
;; jg .drop_with_reset
@@:
test [edx + TCP_segment.Flags], TH_RST
jz @f
test [edx + TCP_segment.Flags], TH_ACK
jz .drop
;tp = tcp_drop(tp, ECONNREFUSED)
jmp .drop
@@:
test [edx + TCP_segment.Flags], TH_SYN
jz .drop
; at this point, segment seems to be valid
test [edx + TCP_segment.Flags], TH_ACK
jz .no_syn_ack
; now, process received SYN in response to an active open
mov eax, [edx + TCP_segment.AckNumber]
mov [ebx + TCP_SOCKET.SND_UNA], eax
cmp eax, [ebx + TCP_SOCKET.SND_NXT]
jle @f
mov [ebx + TCP_SOCKET.SND_NXT], eax
@@:
.no_syn_ack:
mov [ebx + TCP_SOCKET.timer_retransmission], 0 ; disable retransmission
push [edx + TCP_segment.SequenceNumber]
pop [ebx + TCP_SOCKET.IRS]
;;; TODO: tcp_rcvseqinit
mov [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
mov eax, [ebx + TCP_SOCKET.SND_UNA]
cmp eax, [ebx + TCP_SOCKET.ISS]
jle .simultaneous_open
test [edx + TCP_segment.Flags], TH_ACK
jz .simultaneous_open
DEBUGF 1,"TCP: active open\n"
; TODO: update stats
; TODO: set socket state to connected
mov [ebx + TCP_SOCKET.t_state], TCB_ESTABLISHED
; TODO: check if we should scale the connection (567-572)
; TODO: update RTT estimators
jmp .trimthenstep6
.simultaneous_open:
DEBUGF 1,"TCP: simultaneous open\n"
; We have received a syn but no ACK, so we are having a simultaneous open..
mov [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
;-------------------------------------
; Common processing for receipt of SYN
.trimthenstep6:
inc [edx + TCP_segment.SequenceNumber]
cmp cx, [ebx + TCP_SOCKET.RCV_WND]
jle @f
movzx eax, cx
sub ax, [ebx + TCP_SOCKET.RCV_WND]
; TODO: 592
mov cx, [ebx + TCP_SOCKET.RCV_WND]
; TODO...
@@:
;;;;;
jmp .step6
.trim_then_step6:
DEBUGF 1,"Trimming window\n"
;----------------------------
; trim any data not in window
mov eax, [ebx + TCP_SOCKET.RCV_NXT]
sub eax, [edx + TCP_segment.SequenceNumber]
test eax, eax
jz .no_drop
test [edx + TCP_segment.Flags], TH_SYN
jz .no_drop
and [edx + TCP_segment.Flags], not (TH_SYN)
inc [edx + TCP_segment.SequenceNumber]
cmp [edx + TCP_segment.UrgentPointer], 1
jl @f
dec [edx + TCP_segment.UrgentPointer]
jmp .no_drop
@@:
and [edx + TCP_segment.Flags], not (TH_URG)
dec eax
.no_drop:
DEBUGF 1,"Going to drop %u bytes of data", eax
; eax holds number of bytes to drop
;----------------------------------
; Check for entire duplicate packet
cmp eax, ecx
jge .duplicate
;;; TODO: figure 28.30
;------------------------
; Check for duplicate FIN
test [edx + TCP_segment.Flags], TH_FIN
jz @f
inc ecx
cmp eax, ecx
dec ecx
jne @f
mov eax, ecx
and [edx + TCP_segment.Flags], not TH_FIN
or [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
jmp .no_duplicate
@@:
; Handle the case when a bound socket connects to itself
; Allow packets with a SYN and an ACKto continue with the processing
;-------------------------------------
; Generate duplicate ACK if nescessary
; This code also handles simultaneous half-open or self-connects
test eax, eax
jnz .drop_after_ack
cmp [edx + TCP_segment.Flags], TH_ACK
jz .drop_after_ack
.duplicate:
DEBUGF 1,"Duplicate received"
;----------------------------------------
; Update statistics for duplicate packets
;;; TODO
jmp .drop ;;; DROP the packet ??
.no_duplicate:
;-----------------------------------------------
; Remove duplicate data and update urgent offset
add [edx + TCP_segment.SequenceNumber], eax
;;; TODO
sub [edx + TCP_segment.UrgentPointer], ax
jg @f
and [edx + TCP_segment.Flags], not (TH_URG)
mov [edx + TCP_segment.UrgentPointer], 0
@@:
;--------------------------------------------------
; Handle data that arrives after process terminates
cmp [ebx + SOCKET.PID], 0
jge @f
cmp [ebx + TCP_SOCKET.t_state], TCB_CLOSE_WAIT
jle @f
test ecx, ecx
jz @f
;;; Close the socket
;;; update stats
jmp .drop_with_reset
@@:
;----------------------------------------
; Remove data beyond right edge of window
mov eax, [edx + TCP_segment.SequenceNumber]
add eax, ecx
sub eax, [ebx + TCP_SOCKET.RCV_NXT]
sub ax, [ebx + TCP_SOCKET.RCV_WND]
; eax now holds the number of bytes to drop
jle .no_excess_data
;;; TODO: update stats
cmp eax, ecx
jl .dont_drop_all
;;; TODO 700-736
.dont_drop_all:
.no_excess_data:
;-----------------
; Record timestamp
;;; TODO 737-746
;------------------
; Process RST flags
test [edx + TCP_segment.Flags], TH_RST
jz .rst_skip
DEBUGF 1,"Got an RST flag"
mov eax, [ebx + TCP_SOCKET.t_state]
shl eax, 2
jmp dword [eax + .rst_sw_list]
.rst_sw_list:
dd .rst_skip ;TCB_CLOSED
dd .rst_skip ;TCB_LISTEN
dd .rst_skip ;TCB_SYN_SENT
dd .econnrefused ;TCB_SYN_RECEIVED
dd .econnreset ;TCB_ESTABLISHED
dd .econnreset ;TCB_CLOSE_WAIT
dd .econnreset ;TCB_FIN_WAIT_1
dd .rst_close ;TCB_CLOSING
dd .rst_close ;TCB_LAST_ACK
dd .econnreset ;TCB_FIN_WAIT_2
dd .rst_close ;TCB_TIMED_WAIT
.econnrefused:
DEBUGF 1,"Connection refused"
;;; TODO: debug info
jmp .close
.econnreset:
DEBUGF 1,"Connection reset"
;;; TODO: debug info
.close:
DEBUGF 1,"Closing connection"
;;; update stats
.rst_close:
DEBUGF 1,"Closing with reset"
;;; Close the socket
jmp .drop
.rst_skip:
;--------------------------------------
; handle SYN-full and ACK-less segments
test [edx + TCP_segment.Flags], TH_SYN
jz @f
;;; tcp_drop ( ECONNRESET)
jmp .drop_with_reset
test [edx + TCP_segment.Flags], TH_ACK
jz .drop
;----------------
; Process the ACK
cmp [ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
jg .ack_dup
jl .ack_nodup
;;;;;
.ack_dup:
;;;;
.ack_nodup:
;;;; 887
;-------------------------------------------------
; If the congestion window was inflated to account
; for the other side's cached packets, retrace it
;;;; 888 - 902
;------------------------------------------
; RTT measurements and retransmission timer
;;;;; 903 - 926
mov [ebx + TCP_SOCKET.timer_retransmission], 0
mov eax, [ebx + TCP_SOCKET.SND_MAX]
cmp eax, [edx + TCP_segment.AckNumber]
je .all_outstanding
mov [ebx + TCP_SOCKET.timer_retransmission], 120 ;;;; TODO: correct this value
.all_outstanding:
;-------------------------------------------
; Open congestion window in response to ACKs
;;;;
;------------------------------------------
; Remove acknowledged data from send buffer
lea eax, [ebx + snd]
mov ecx, ecx ;;;; 943 - 956
call SOCKET_ring_free
;---------------------------------------
; Wake up process waiting on send buffer
mov eax, ebx
call SOCKET_notify_owner
mov eax, [ebx + TCP_SOCKET.t_state]
shl eax, 2
jmp dword [eax + .ACK_sw_list]
.ACK_sw_list:
dd .step6 ;TCB_CLOSED
dd .step6 ;TCB_LISTEN
dd .step6 ;TCB_SYN_SENT
dd .step6 ;TCB_SYN_RECEIVED
dd .step6 ;TCB_ESTABLISHED
dd .step6 ;TCB_CLOSE_WAIT
dd ._963 ;TCB_FIN_WAIT_1
dd ._958 ;TCB_CLOSING
dd ._999 ;TCB_LAST_ACK
dd .step6 ;TCB_FIN_WAIT_2
dd ._1010 ;TCB_TIMED_WAIT
._963:
jmp .step6
._958:
jmp .step6
._999:
jmp .step6
._1010:
jmp .step6
align 4
.step6:
DEBUGF 1,"step 6\n"
;--------------------------
; update window information
test [edx + TCP_segment.Flags], TH_ACK
jz .no_window_update
mov eax, [ebx + TCP_SOCKET.SND_WL1]
cmp eax, [edx + TCP_segment.SequenceNumber]
;;;; 1021
;----------------------------------
; Keep track of pure window updates
test ecx, ecx
jz @f
mov eax, [ebx + TCP_SOCKET.SND_WL2]
cmp eax, [edx + TCP_segment.AckNumber]
jne @f
;; mov eax, tiwin
cmp eax, [ebx + TCP_SOCKET.SND_WND]
jle @f
;;; update stats
@@:
;; mov eax, incoming window
cmp eax, [ebx + TCP_SOCKET.max_sndwnd]
jle @f
mov [ebx + TCP_SOCKET.max_sndwnd], eax
@@:
mov [ebx + TCP_SOCKET.SND_WND], eax
mov eax, [edx + TCP_segment.SequenceNumber]
mov [ebx + TCP_SOCKET.SND_WL1], eax
mov eax, [edx + TCP_segment.AckNumber]
mov [ebx + TCP_SOCKET.SND_WL2], eax
;;; needoutput = 1
.no_window_update:
;-----------------
; process URG flag
test [edx + TCP_segment.Flags], TH_URG
jz .not_urgent
cmp [edx + TCP_segment.UrgentPointer], 0
jz .not_urgent
cmp [ebx + TCP_SOCKET.t_state], TCB_TIMED_WAIT
je .not_urgent
; Ignore bogus urgent offsets
;;; 1040-1050
movzx eax, [edx + TCP_segment.UrgentPointer]
add eax, [ebx + rcv.size]
cmp eax, SOCKET_MAXDATA
jle .not_urgent
mov [edx + TCP_segment.UrgentPointer], 0
and [edx + TCP_segment.Flags], not (TH_URG)
jmp .do_data
.not_urgent:
;--------------------------------------
; processing of received urgent pointer
;;; TODO (1051-1093)
;--------------------------------
; process the data in the segment
.do_data:
DEBUGF 1,"TCP: do data:\n"
test [edx + TCP_segment.Flags], TH_FIN
jnz .process_fin
test [ebx + TCP_SOCKET.t_state], TCB_FIN_WAIT_1
jge .dont_do_data
DEBUGF 1,"Processing data in segment\n"
;;; NOW, process the data
jmp .final_processing
.dont_do_data:
;---------------
; FIN processing
.process_fin:
DEBUGF 1,"Processing FIN\n"
mov eax, [ebx + TCP_SOCKET.t_state]
shl eax, 2
jmp dword [eax + .FIN_sw_list]
.FIN_sw_list:
dd .no_fin ;TCB_CLOSED
dd .no_fin ;TCB_LISTEN
dd .no_fin ;TCB_SYN_SENT
dd ._1131 ;TCB_SYN_RECEIVED
dd ._1131 ;TCB_ESTABLISHED
dd .no_fin ;TCB_CLOSE_WAIT
dd ._1139 ;TCB_FIN_WAIT_1
dd .no_fin ;TCB_CLOSING
dd .no_fin ;TCB_LAST_ACK
dd ._1147 ;TCB_FIN_WAIT_2
dd ._1156 ;TCB_TIMED_WAIT
._1131:
._1139:
._1147:
._1156:
.no_fin:
;-----------------
; Final processing
.final_processing:
DEBUGF 1,"Final processing\n"
;;; if debug enabled, output packet
;test ;;;needoutput = 1
;jnz .outputnow
test [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
jnz .ack_now
mov [ebx + SOCKET.lock], 0
call kernel_free
add esp, 4
ret
.ack_now:
DEBUGF 1,"ACK now!\n"
push ebx
mov eax, ebx
call TCP_output
pop ebx
mov [ebx + SOCKET.lock], 0
call kernel_free
add esp, 4
ret
;------------------------------------------
; Generate an ACK, droping incoming segment
align 4
.drop_after_ack:
DEBUGF 1,"Drop after ACK\n"
test [edx + TCP_segment.Flags], TH_RST
jnz .drop
and [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
push ebx
mov eax, ebx
call TCP_output
pop ebx
mov [ebx + SOCKET.lock], 0
call kernel_free
add esp, 4
ret
;-------------------------------------------
; Generate an RST, dropping incoming segment
align 4
.drop_with_reset:
DEBUGF 1,"Drop with reset\n"
test [edx + TCP_segment.Flags], TH_RST
jnz .drop
;;; if its a multicast/broadcast, also drop
test [edx + TCP_segment.Flags], TH_ACK
jnz .respond_ack
test [edx + TCP_segment.Flags], TH_SYN
jnz .respond_syn
mov [ebx + SOCKET.lock], 0
call kernel_free
add esp, 4
ret
.respond_ack:
;;;;
call TCP_respond_segment
jmp .destroy_new_socket
.respond_syn:
;;;;
call TCP_respond_segment
jmp .destroy_new_socket
;-----
; Drop
align 4
.drop:
DEBUGF 1,"Dropping packet\n"
;;;; If debugging options are enabled, output the packet somwhere
.destroy_new_socket:
;;;; kill the newly created socket
mov [ebx + SOCKET.lock], 0
call kernel_free
add esp, 4
ret
;---------------------------
;
; 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_output
;
; IN: eax = socket pointer
;; esi = ptr to data
;; ecx = number of data bytes
;
; 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]
jle .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
sub ebx, [eax + TCP_SOCKET.SND_UNA] ;
mov ecx, [eax + TCP_SOCKET.SND_WND] ; determine window
cmp ecx, [eax + TCP_SOCKET.SND_CWND] ;
jl @f ;
mov ecx, [eax + TCP_SOCKET.SND_CWND] ;
@@: ;
call TCP_outflags ; in dl
; 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_persist_timeout
test ecx, ecx
jnz .no_zero_window
cmp ebx, [eax + snd.size]
jge @f
and dl, not (TH_FIN) ; clear the FIN flag ??? how can it be set before?
@@:
inc ecx
jmp .no_persist_timeout
.no_zero_window:
mov [eax + TCP_SOCKET.timer_persist], 0 ;;;;
mov [eax + TCP_SOCKET.t_rxtshift], 0
.no_persist_timeout:
;;;106
mov esi, [eax + snd.size]
cmp esi, ecx
jl @f
mov esi, ecx
@@:
sub esi, ebx
cmp esi, -1
jne .not_minus_one
; If FIN has been set, but not ACKed, and we havent been called to retransmit,
; len (esi) will be -1
; Otherwise, window shrank after we sent into it.
; If window shrank to 0, cancel pending retransmit and pull SND_NXT back to (closed) window
; We will enter persist state below.
; If window didn't close completely, just wait for an ACK
xor esi, esi
test ecx, ecx
jnz @f
mov [eax + TCP_SOCKET.timer_retransmission], 0 ; cancel retransmit
push [eax + TCP_SOCKET.SND_UNA]
pop [eax + TCP_SOCKET.SND_NXT]
@@:
.not_minus_one:
;;; 124
cmp esi, [eax + TCP_SOCKET.t_maxseg]
jle @f
mov esi, [eax + TCP_SOCKET.t_maxseg]
;sendalot = 1
@@:
;;; 128
mov edi, [eax + TCP_SOCKET.SND_NXT]
add edi, esi ; len
sub edi, [eax + TCP_SOCKET.SND_UNA]
add edi, [eax + snd.size]
cmp edi, 0
jle @f
and dl, not (TH_FIN) ; clear the FIN flag
@@:
; set ecx to space available in receive buffer
; From now on, ecx will be the window we advertise to the other end
mov ecx, SOCKET_MAXDATA
sub ecx, [eax + rcv.size]
;------------------------------
; Sender silly window avoidance
cmp ecx, [eax + TCP_SOCKET.t_maxseg]
je .send
;;; TODO: 144-145
test [eax + TCP_SOCKET.t_force], -1
jnz .send
mov ebx, [eax + TCP_SOCKET.max_sndwnd]
shr ebx, 1
cmp ecx, ebx
jge .send
mov ebx, [eax + TCP_SOCKET.SND_NXT]
cmp ebx, [eax + TCP_SOCKET.SND_MAX]
jl .send
;----------------------------------------
; Check if a window update should be sent
test ecx, ecx ; window
jz .no_window
;;; TODO 154-172
.no_window:
;--------------------------
; Should a segment be sent?
test [ebx + TCP_SOCKET.t_flags], TF_ACKNOW
jnz .send
test dl, TH_SYN + TH_RST
jnz .send
mov eax, [ebx + TCP_SOCKET.SND_UP]
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
jg .send
test dl, TH_FIN
jz .enter_persist
test [ebx + TCP_SOCKET.t_flags], TF_SENTFIN
jnz .send
mov eax, [ebx + TCP_SOCKET.SND_NXT]
cmp eax, [ebx + TCP_SOCKET.SND_UNA]
je .send
;--------------------
; Enter persist state
.enter_persist:
DEBUGF 1,"Entering persist state\n"
;--------------------------------------
; No reason to send a segment, just ret
DEBUGF 1,"No reason to send a segment\n"
ret
;-----------------------------------------------
;
; Send a segment
;
; eax = socket pointer
; dl = flags
;
;-----------------------------------------------
.send:
DEBUGF 1,"Preparing to send a segment\n"
mov edi, TCP_segment.Data ; edi will contain headersize
sub esp, 8 ; create some space on stack
push eax ; save this too..
;------------------------------------
; Send options with first SYN segment
test dl, TH_SYN
jz .no_options
push [eax + TCP_SOCKET.ISS]
pop [eax + TCP_SOCKET.SND_NXT]
test [eax + TCP_SOCKET.t_flags], TF_NOOPT
jnz .no_options
mov ecx, 1460
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 esi, [timer_ticks]
bswap esi
push esi
pushw 0
pushd TCP_OPT_TIMESTAMP + 10 shl 8 + TCP_OPT_NOP shl 16 + TCP_OPT_NOP shl 24
add di, 10
.no_timestamp:
;; TODO: check if we dont exceed the max segment size
.no_options:
; eax = socket ptr
; edx = flags
; ecx = data size
; edi = header size
; esi = snd ring buff ptr
xor ecx, ecx ;;;;;
add ecx, edi ; total TCP segment size
; Start by pushing all TCP header values in reverse order on stack
; (essentially, creating the tcp header!)
pushw 0 ; .UrgentPointer dw ?
pushw 0 ; .Checksum dw ?
pushw 0x00a0 ; .Window dw ? ;;;;;;;
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 ?
ntohld [esp]
push [eax + TCP_SOCKET.SND_NXT] ; .SequenceNumber dd ?
ntohld [esp]
push [eax + TCP_SOCKET.RemotePort] ; .DestinationPort dw ?
ntohlw [esp]
push [eax + TCP_SOCKET.LocalPort] ; .SourcePort dw ?
ntohlw [esp]
push edi ; header size
; Create the IP packet
mov ebx, [eax + IP_SOCKET.LocalIP] ; source ip
mov eax, [eax + IP_SOCKET.RemoteIP] ; dest ip
; mov ecx, ; data length
; mov dx, ; fragment id
mov di, IP_PROTO_TCP shl 8 + 128
call IPv4_output
jz .fail
;-----------------------------------------
; Move TCP header from stack to TCP packet
; pop ecx ; header size
; mov esi, esp
; add esp, ecx
; shr ecx, 2
; rep movsd
mov ecx, [esp]
lea esi, [esp+4]
shr ecx, 2
rep movsd
pop ecx
add esp, ecx
mov [esp + 4+4], edx ; packet size
mov [esp + 4], eax ; packet ptr
mov edx, edi
sub edx, ecx
;--------------
; Copy the data
; eax = ptr to ring struct
; ecx = buffer size
; edi = ptr to buffer
mov eax, [esp] ; socket ptr
push ecx edx
add eax, snd
call SOCKET_ring_read
pop esi ecx
pop eax
;-------------------------------------------------------------
; Create the checksum (we have already pushed IPs onto stack)
DEBUGF 1,"checksum: ptr=%x size=%u\n", esi, ecx
TCP_checksum (eax + IP_SOCKET.LocalIP), (eax + IP_SOCKET.RemoteIP)
mov [esi+TCP_segment.Checksum], dx
;----------------
; Send the packet
DEBUGF 1,"Sending TCP Packet to device %x\n", ebx
call [ebx + NET_DEVICE.transmit]
ret
.fail:
pop ecx
add esp, ecx
add esp, 4+4+8+4
DEBUGF 1,"TCP_output: failed\n"
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 ; TCB_CLOSED
db 0 ; TCB_LISTEN
db TH_SYN ; TCB_SYN_SENT
db TH_SYN + TH_ACK ; TCB_SYN_RECEIVED
db TH_ACK ; TCB_ESTABLISHED
db TH_ACK ; TCB_CLOSE_WAIT
db TH_SYN + TH_ACK ; TCB_FIN_WAIT_1
db TH_SYN + TH_ACK ; TCB_CLOSING
db TH_SYN + TH_ACK ; TCB_LAST_ACK
db TH_ACK ; TCB_FIN_WAIT_2
db TH_ACK ; TCB_TIMED_WAIT
;-------------------------
;
; TCP_drop
;
; IN: eax = socket ptr
;
; OUT: /
;
;-------------------------
align 4
TCP_drop:
DEBUGF 1,"TCP_drop\n"
; cmp [eax + TCP_SOCKET.t_state], TCB_SYN_RECEIVED
; jl .no_syn_received
mov [eax + TCP_SOCKET.t_state], TCB_CLOSED
call TCP_output
; .no_syn_received:
ret
;---------------------------------------
;
; The easy way to send an ACK/RST/keepalive segment
;
; TCP_respond_socket:
;
; IN: ebx = socket ptr
; cl = flags
;
;--------------------------------------
align 4
TCP_respond_socket:
DEBUGF 1,"TCP_respond_socket\n"
;---------------------
; Create the IP packet
push cx ebx
mov eax, [ebx + IP_SOCKET.RemoteIP]
mov ebx, [ebx + IP_SOCKET.LocalIP]
mov ecx, TCP_segment.Data
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]
rol ax, 8
stosw
mov ax, [esi + TCP_SOCKET.RemotePort]
rol ax, 8
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
stosb
mov al, cl
stosb
mov ax, [esi + TCP_SOCKET.RCV_WND]
rol ax, 8
stosw ; window
xor eax, eax
stosd ; checksum + urgentpointer
;---------------------
; Fill in the checksum
.checksum:
sub edi, TCP_segment.Data
mov ecx, TCP_segment.Data
xchg esi, edi
TCP_checksum (edi + IP_SOCKET.LocalIP), (esi + IP_SOCKET.RemoteIP)
mov [esi+TCP_segment.Checksum], dx
;--------------------
; And send the segment
call [ebx + NET_DEVICE.transmit]
ret
.error:
DEBUGF 1,"TCP_respond failed\n"
add esp, 2+4
ret
;-------------------------
; TCP_respond.segment:
;
; IN: edx = segment ptr (a previously received segment)
; cl = flags
align 4
TCP_respond_segment:
DEBUGF 1,"TCP_respond_segment\n"
;---------------------
; Create the IP packet
push cx edx
mov ebx, [edx - 20 + IPv4_Packet.SourceAddress] ;;;; and what if ip packet had options?!
mov eax, [edx - 20 + IPv4_Packet.DestinationAddress] ;;;
mov ecx, TCP_segment.Data
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 a received segment
mov ax, [esi + TCP_segment.DestinationPort]
rol ax, 8
stosw
mov ax, [esi + TCP_segment.SourcePort]
rol ax, 8
stosw
mov eax, [esi + TCP_segment.AckNumber]
bswap eax
stosd
xor eax, eax
stosd
mov al, 0x50 ; Dataoffset: 20 bytes
stosb
mov al, cl
stosb
mov ax, 1280
rol ax, 8
stosw ; window
xor eax, eax
stosd ; checksum + urgentpointer
;---------------------
; Fill in the checksum
.checksum:
lea esi, [edi - TCP_segment.Data]
mov ecx, TCP_segment.Data
TCP_checksum (esi - 20 + IPv4_Packet.DestinationAddress), (esi - 20 + IPv4_Packet.DestinationAddress)
mov [esi+TCP_segment.Checksum], dx
;--------------------
; And send the segment
call [ebx + NET_DEVICE.transmit]
ret
.error:
DEBUGF 1,"TCP_respond failed\n"
add esp, 2+4
ret
;---------------------------------------------------------------------------
;
; TCP_API
;
; This function is called by system function 75
;
; IN: subfunction number in bl
; device number in bh
; ecx, edx, .. depends on subfunction
;
; OUT:
;
;---------------------------------------------------------------------------
align 4
TCP_API:
movzx eax, bh
shl eax, 2
test bl, bl
jz .packets_tx ; 0
dec bl
jz .packets_rx ; 1
.error:
mov eax, -1
ret
.packets_tx:
add eax, TCP_segments_tx
mov eax, [eax]
ret
.packets_rx:
add eax, TCP_segments_rx
mov eax, [eax]
ret