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;-----------------------------------------------------------------

;

; 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 ", 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_not_locked

;-------------------------------

; 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_not_locked

	DEBUGF	1,"Checksum is correct\n"

	sub	ecx, esi	; update packet size

	jl	.drop_not_locked

	DEBUGF	1,"we got %u bytes of data\n", ecx

;-----------------------------------------------------------------------------------------

; 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

	ntohd	[edx + TCP_segment.SequenceNumber]

	ntohd	[edx + TCP_segment.AckNumber]

	ntohw	[edx + TCP_segment.Window]

	ntohw	[edx + TCP_segment.UrgentPointer]

	ntohw	[edx + TCP_segment.SourcePort]

	ntohw	[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_not_locked

	cmp	[ebx + SOCKET.Domain], AF_INET4

	jne	.socket_loop

	cmp	[ebx + SOCKET.Protocol], 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			; edi is source ip from packet

	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_not_locked

;----------------

; Lock the socket

	add	ebx, SOCKET.lock

	DEBUGF	1,"lock: %x\n", [ebx]

	call	wait_mutex

	sub	ebx, SOCKET.lock

	DEBUGF	1,"Socket locked\n"

;---------------------------------------

; unscale the window into a 32 bit value

	movzx	eax, [edx + TCP_segment.Window]

	push	ecx

	mov	cl, [ebx + TCP_SOCKET.SND_SCALE]

	shl	eax, cl

	mov	dword [edx + TCP_segment.Window], eax	; word after window is checksum, we dont need checksum anymore

	pop	ecx

;-----------------------------------

; Is this socket a listening socket?

	test	[ebx + SOCKET.options], SO_ACCEPTCON

	jz	.no_listening_socket

	call	SOCKET_fork

	jz	.drop

	push	[edx + TCP_segment.DestinationPort]

	pop	[eax + TCP_SOCKET.LocalPort]

	push	[edx - IPv4_Packet.DataOrOptional + IPv4_Packet.DestinationAddress]	;;; FIXME

	pop	[eax + IP_SOCKET.LocalIP]

	push	[edx - IPv4_Packet.DataOrOptional + IPv4_Packet.SourceAddress]	   ;;; FIXME

	pop	[eax + IP_SOCKET.RemoteIP]

	mov	[eax + TCP_SOCKET.t_state], TCB_LISTEN

	jmp	.not_uni_xfer

  .no_listening_socket:

;-------------------------------------

; 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	.not_uni_xfer					; also no header prediction

	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\n", 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\n"

	;;;;;

       @@:

	add	edi, 3

	jmp	.opt_loop

  .opt_timestamp:

	cmp	byte [edi+1], 10

	jne	.no_options

	DEBUGF	1,"Got timestamp option\n"

	;;;;;

	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

	mov	eax, dword [edx + TCP_segment.Window]

	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	eax, [edx + TCP_segment.AckNumber]

	cmp	eax, [ebx + TCP_SOCKET.SND_MAX]

	jg	.not_uni_xfer

; - The acknowledgment field in the segment is greater than the largest unacknowledged sequence number.

	sub	eax, [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

	pusha

	mov	ecx, eax

	lea	eax, [ebx + STREAM_SOCKET.snd]

	call	SOCKET_ring_free

	popa

; update window pointers

	mov	eax, [edx + TCP_segment.AckNumber]

	dec	eax

	mov	[ebx + TCP_SOCKET.SND_WL1], eax

; Stop retransmit timer

	mov	[ebx + TCP_SOCKET.timer_ack], 0

; Awaken waiting processes

	mov	eax, ebx

	call	SOCKET_notify_owner

;; Generate more output     FIXME

;;        mov     eax, ebx

;;        call    TCP_output

;;

;;        jmp     .drop

	jmp	.ack_processed

;-------------------------------------------------

; 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).

;;; TODO

	jnz	.not_uni_xfer

; Complete processing of received data

	DEBUGF	1,"header prediction: we are receiver\nreceiving %u bytes of data\n", ecx

	pusha

	add	esi, edx

	lea	eax, [ebx + STREAM_SOCKET.rcv]

	call	SOCKET_ring_write			; Add the data to the socket buffer

	mov	eax, ebx

	call	SOCKET_notify_owner

	popa

	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, do it the slow way

  .not_uni_xfer:

	DEBUGF	1,"Header prediction failed\n"

; Calculate receive window size

;;;;

	cmp	[ebx + TCP_SOCKET.t_state], TCB_LISTEN

	je	.LISTEN

	cmp	[ebx + TCP_SOCKET.t_state], TCB_SYN_SENT

	je	.SYN_SENT

	jmp	.NOT_LISTEN_OR_SYN_SENT

;-------------

; Passive Open

align 4

.LISTEN:

	DEBUGF	1,"TCP state: listen\n"

	test	[edx + TCP_segment.Flags], TH_RST	;;; TODO: kill new socket on error

	jnz	.drop

	test	[edx + TCP_segment.Flags], TH_ACK

	jnz	.drop_with_reset

	test	[edx + TCP_segment.Flags], TH_SYN

	jz	.drop

;;; TODO: check if it's a broadcast or multicast, and drop if so

	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]

	TCP_sendseqinit eax

	TCP_rcvseqinit eax

	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  ;;;; macro

	add	eax, STREAM_SOCKET.snd

	call	SOCKET_ring_create

	add	eax, STREAM_SOCKET.rcv - STREAM_SOCKET.snd

	call	SOCKET_ring_create

	lea	ebx, [eax - STREAM_SOCKET.rcv]

	mov	[ebx + SOCKET.lock], 0

	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

	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

	mov	eax, ebx

	mov	ebx, ECONNREFUSED

	call	TCP_drop

	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]

	TCP_rcvseqinit ebx

	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

; set socket state to connected

	mov	[ebx + SOCKET.state],1	;;;; FIXME

	mov	[ebx + TCP_SOCKET.t_state], TCB_ESTABLISHED

;;; TODO: check if we should scale the connection (567-572)

;;; TODO: update RTT estimators

	jmp	.trim_then_step6

  .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

  .trim_then_step6:

	inc	[edx + TCP_segment.SequenceNumber]

;;; TODO: Drop any received data that follows receive window (590)

	mov	eax, [edx + TCP_segment.SequenceNumber]

	mov	[ebx + TCP_SOCKET.RCV_UP], eax

	dec	eax

	mov	[ebx + TCP_SOCKET.SND_WL1], eax

	jmp	.ack_processed

  .NOT_LISTEN_OR_SYN_SENT:

	DEBUGF	1,"Slow TCP input: not listen or syn_sent state\n"

;--------------------------------------------

; Protection Against Wrapped Sequence Numbers

; First, check if timestamp is present

;;;; TODO

; Then, check if at least some bytes of data are within window

;;;; TODO

;----------------------------

; trim any data not in window

; check for duplicate data at beginning of segment

	mov	eax, [ebx + TCP_SOCKET.RCV_NXT]

	sub	eax, [edx + TCP_segment.SequenceNumber]

	jz	.no_duplicate

	test	[edx + TCP_segment.Flags], TH_SYN

	jz	.no_drop

; remove duplicate syn

	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

	jz	.no_duplicate

  .no_drop:

	DEBUGF	1,"Going to drop %u out of %u bytes\n", eax, ecx

; eax holds number of bytes to drop

; Check for entire duplicate packet

	cmp	eax, ecx

	jge	.duplicate

;;; TODO: apply 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\n"

;----------------------------------------

; 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

	jg	@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\n"

;;; Close the socket

	jmp	.drop

  .rst_skip:

;--------------------------------------

; handle SYN-full and ACK-less segments

	test	[edx + TCP_segment.Flags], TH_SYN

	jz	@f

	mov	ebx, ECONNRESET

	call	TCP_drop

	jmp	.drop_with_reset

	test	[edx + TCP_segment.Flags], TH_ACK

	jz	.drop

      @@:

;---------------

; ACK processing

	cmp	[ebx + TCP_SOCKET.t_state], TCB_SYN_RECEIVED

	jnz	.no_syn_rcv

	DEBUGF	1,"TCP state = syn received\n"

	;;;;;  801-815

  .no_syn_rcv:

; check for duplicate ACK

	mov	eax, [edx + TCP_segment.AckNumber]

	cmp	eax, [ebx + TCP_SOCKET.SND_UNA]

	jg	.not_dup_ack

	DEBUGF	1,"Duplicate ACK\n"

	test	ecx, ecx

	jnz	.ack_processed

	mov	eax, dword [edx + TCP_segment.Window]

	cmp	eax, [ebx + TCP_SOCKET.SND_WND]

	jne	.ack_processed

; Process the duplicate ACK

	;;;;; 833 - 878

;;;        call    TCP_output

	jmp	.drop

  .not_dup_ack:

	DEBUGF	1,"new ACK\n"

;-------------------------------------------------

; If the congestion window was inflated to account

; for the other side's cached packets, retract 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 (use a macro for it)

  .all_outstanding:

;-------------------------------------------

; Open congestion window in response to ACKs

	;;;;

;------------------------------------------

; Remove acknowledged data from send buffer

	pusha

	mov	ecx, [edx + TCP_segment.AckNumber]

	sub	ecx, [ebx + TCP_SOCKET.SND_UNA] 	; ecx now holds number of bytes acked

	lea	eax, [ebx + STREAM_SOCKET.snd]

	call	SOCKET_ring_free

	popa

; Wake up process waiting on send buffer

	mov	eax, ebx

	call	SOCKET_notify_owner

; Update TCB

	mov	eax, [edx + TCP_segment.AckNumber]

	mov	[ebx + TCP_SOCKET.SND_UNA], eax

	cmp	eax, [ebx + TCP_SOCKET.SND_NXT]

	jl	@f

	mov	[ebx + TCP_SOCKET.SND_NXT], eax

       @@:

; General ACK handling complete

; Now do the state-specific ones

	mov	eax, [ebx + TCP_SOCKET.t_state]

	jmp	dword [eax*4 + .ACK_sw_list]

  .ACK_sw_list:

	dd	.ack_processed	;TCB_CLOSED

	dd	.ack_processed	;TCB_LISTEN

	dd	.ack_processed	;TCB_SYN_SENT

	dd	.ack_processed	;TCB_SYN_RECEIVED

	dd	.ack_processed	;TCB_ESTABLISHED

	dd	.ack_processed	;TCB_CLOSE_WAIT

	dd	.ack_fw1	;TCB_FIN_WAIT_1

	dd	.ack_c		;TCB_CLOSING

	dd	.ack_la 	;TCB_LAST_ACK

	dd	.ack_processed	;TCB_FIN_WAIT_2

	dd	.ack_tw 	;TCB_TIMED_WAIT

  .ack_fw1:	; 963

	jmp	.ack_processed

  .ack_c:	; 958

	jmp	.ack_processed

  .ack_la:	; 999

	jmp	.ack_processed

  .ack_tw:	; 1010

	jmp	.ack_processed

align 4

  .ack_processed:	; (step 6)

	DEBUGF	1,"ACK processed\n"

;----------------------------------------------

; check if we need to 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]

	jl	.update_window

	jg	@f

	mov	eax, [ebx + TCP_SOCKET.SND_WL2]

	cmp	eax, [edx + TCP_segment.AckNumber]

	jl	.update_window

	jg	.no_window_update

       @@:

	mov	eax, [ebx + TCP_SOCKET.SND_WL2]

	cmp	eax, [edx + TCP_segment.AckNumber]

	jne	.no_window_update

	movzx	eax, [edx + TCP_segment.Window]

	cmp	eax, [ebx + TCP_SOCKET.SND_WND]

	jle	.no_window_update

  .update_window:

	DEBUGF	1,"Updating window\n"

; 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, dword [edx + TCP_segment.Window]

	cmp	eax, [ebx + TCP_SOCKET.max_sndwnd]

	jle	@f

	mov	[ebx + TCP_SOCKET.max_sndwnd], eax

       @@:

	mov	[ebx + TCP_SOCKET.SND_WND], eax

	push	[edx + TCP_segment.SequenceNumber]

	pop	[ebx + TCP_SOCKET.SND_WL1]

	push	[edx + TCP_segment.AckNumber]

	pop	[ebx + TCP_SOCKET.SND_WL2]

	;;; 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 + STREAM_SOCKET.rcv + RING_BUFFER.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)