PR#3
PREFIX /A2OSX.BUILD
LOMEM $900
INC 1
AUTO 6
				.LIST OFF	
*--------------------------------------
TCP.IN			jsr IP.FillSKT.TemplateSrcDst
				
				ldy #S.TCP.SRCPORT
				lda (ZPFrameInPtr),y
				sta SKT.Template+S.SOCKET.DST.PORT+1
				iny
				lda (ZPFrameInPtr),y
				sta SKT.Template+S.SOCKET.DST.PORT
				
				ldy #S.TCP.DSTPORT
				lda (ZPFrameInPtr),y
				sta SKT.Template+S.SOCKET.SRC.PORT+1
				iny
				lda (ZPFrameInPtr),y
				sta SKT.Template+S.SOCKET.SRC.PORT
				
				lda hSocketTable
				>SYSCALL GetMemPtrA
				>STYA ZPPtrSKT
				
				ldx #0
				
.3				lda (ZPPtrSKT)
				beq .7
				cmp #S.SOCKET.SOCK.STREAM
				bne .7
				
				ldy #S.SOCKET.SRC.ADDR
				
.4				lda SKT.Template,y
				cmp (ZPPtrSKT),y
				bne .7						Not for this socket...
				
				iny
				cpy #S.SOCKET.SRC.PORT+2
				bne .4
				
				ldy #S.SOCKET.SO
				lda (ZPPtrSKT),y
				and #S.SOCKET.SO.ACCEPTCONN		Listening socket?
				beq .5					no, go check if Dst Match
	
				ldy #S.TCP.OPTIONS		yes, only accept SYN packet
				lda (ZPFrameInPtr),y

				cmp #S.TCP.OPTIONS.SYN	SYN only, if SYN.ACK, pass to regular socket
				beq TCP.IN.JMP.LISTEN
			
.5				ldy #S.SOCKET.DST.ADDR

.6				lda SKT.Template,y		regular socket, check remote ADDR/PORT
				cmp (ZPPtrSKT),y
				bne .7
				iny
				cpy #S.SOCKET.DST.PORT+2
				bne .6
			
				ldy #S.TCP.OPTIONS
				lda (ZPFrameInPtr),y
				and #S.TCP.OPTIONS.RST		RST ? go Kill this socket.
				bne TCP.IN.RST
				
				ldy #S.SOCKET.TCP.STATUS
				lda (ZPPtrSKT),y
				cmp #S.SOCKET.TCP.STATUS.TIMEWT
				bcs *
				asl
				tax
				
				jmp (L.TCP.IN.JMP,x)
				
.7				lda ZPPtrSKT
				clc
				adc #S.SOCKET
				sta ZPPtrSKT
				bcc .8
				inc ZPPtrSKT+1
				
.8				inx
				cpx #K.SKTTABLE.SIZE
				bne .3
				
.9				clc						Discard frame
				rts
*--------------------------------------
TCP.IN.RST		jmp SKT.Destroy
*--------------------------------------
TCP.IN.JMP.LISTEN
				lda #S.SOCKET.SOCK.STREAM
				sta SKT.Template+S.SOCKET.SOCK
				stz SKT.Template+S.SOCKET.SO
				stz SKT.Template+S.SOCKET.TCP.STATUS
				
				>PUSHW L.SKT.Template

				jsr SKT.New.Listen		Assign SEQNUM
				bcs .99
				
				sty .1+1
				sta .2+1
				txa
				
				jsr SKT.AddToQueueA
				
				bcs .99					Queued successfully ?

.1				lda #$ff
				sta ZPPtrSKT
.2				lda #$ff
				sta ZPPtrSKT+1

				ldy #S.TCP.SEQ.NUMBER+3	Get Remote SEQ
				ldx #3
				
				sec
				
.3				lda (ZPFrameInPtr),y	Set ACK=SEQ+1 for new socket...
				adc #0
				sta SKT.TCBCache+S.TCB.ACKNUM,x
				sta SKT.TCBCache+S.TCB.NEXTSEQ,x
				dey
				dex
				bpl .3
				
				jsr SKT.StoreTCB
				
				jsr ARP.AddFromFrameInPtr

				lda #S.TCP.OPTIONS.SYN+S.TCP.OPTIONS.ACK
				jsr TCP.OUT.SendOpt		Send SYN.ACK
				bcs .9

				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.SYNRCVD
				sta (ZPPtrSKT),y
				
				clc
				rts
				
.9				lda #0					error
				sta (ZPPtrSKT)			clear this socket
				lda #ERR.SKT.OOS
.99				rts
*--------------------------------------
TCP.IN.JMP.SYNSENT
				ldy #S.TCP.OPTIONS		SYN Send, only accept SYN.ACK packet, then Send ACK 
				lda (ZPFrameInPtr),y
				cmp #S.TCP.OPTIONS.SYN+S.TCP.OPTIONS.ACK
				bne .8

				jsr SKT.GetTCB
				
				ldx #3
				ldy #S.TCP.ACK.NUMBER+3

				sec						Check if ACK=my SEQ+1

.1				lda SKT.TCBCache+S.TCB.ACKNUM,x
				adc #0
				sta	SKT.TCBCache+S.TCB.ACKNUM,x 
				eor (ZPFrameInPtr),y
				bne .8
				dey
				dex
				bpl .1

				lda #S.TCP.OPTIONS.ACK
				jsr TCP.OUT.SendOpt
				bcs .9
				
				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.ESTBLSH
				sta (ZPPtrSKT),y				
				
.8				clc
.9				rts
*--------------------------------------
TCP.IN.JMP.SYNRCVD
				ldy #S.TCP.OPTIONS		SYN Recieved, SYN.ACK Sent, only accept ACK packet
				lda (ZPFrameInPtr),y
				cmp #S.TCP.OPTIONS.ACK
				bne .8
				
				jsr SKT.GetTCB
			
				ldx #3
				ldy #S.TCP.ACK.NUMBER+3

				sec
				
.1				lda	SKT.TCBCache+S.TCB.SEQNUM,x 	Check if ACK=my SEQ+1
				adc #0
				sta	SKT.TCBCache+S.TCB.SEQNUM,x
				eor (ZPFrameInPtr),y
				bne .8
				dey
				dex
				bpl .1
				
				jsr SKT.StoreTCB
				bcs .9
				
				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.ESTBLSH
				sta (ZPPtrSKT),y	
			
.8				clc
.9				rts
*--------------------------------------
TCP.IN.JMP.ESTBLSH
				jsr SKT.GetTCB

				ldy #S.TCP.OPTIONS
				lda (ZPFrameInPtr),y
				and #S.TCP.OPTIONS.ACK	Remote side ACKed data ?
				beq .1
				
				jsr SKT.AckDataToSktOut	Yes, Discard sent data
				jsr SKT.StoreTCB		and update SKT

.1				jsr TCP.IN.SetDataInPtrAndLen
				
				lda ZPDataInLen			Incoming Data in this frame ?
				ora ZPDataInLen+1
				beq .2					No data, ...

				jsr SKT.AddDataToSktIn	yes, queue data if there is room for....
								
.2				ldy #S.TCP.OPTIONS
				lda (ZPFrameInPtr),y
				and #S.TCP.OPTIONS.FIN
				beq .8
				
				ldy #S.TCP.OPTIONS
				lda (ZPPtrSKT),y
				ora #S.TCP.OPTIONS.ACK		ACK the FIN....
				sta (ZPPtrSKT),y
				
				jsr TCP.OUT.I			SKT.GetTCB called, try to ACK the FIN
				bcs .9
				
				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.CLWAIT
				sta (ZPPtrSKT),y

.8				clc
.9				rts
*--------------------------------------
TCP.IN.JMP.CLWAIT
				clc						Wait for SKT.CloseA from Daemon
				rts
*--------------------------------------
TCP.IN.JMP.LASTACK
				ldy #S.TCP.OPTIONS		only accept ACK packet
				lda (ZPFrameInPtr),y
				cmp #S.TCP.OPTIONS.ACK
				bne .8
				
				jmp SKT.Destroy
				
.8				clc
				rts
*--------------------------------------
TCP.IN.JMP.FINWT1
				ldy #S.TCP.OPTIONS		only accept ACK packet
				lda (ZPFrameInPtr),y
				cmp #S.TCP.OPTIONS.ACK
				bne .1
				
				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.FINWT2
				sta (ZPPtrSKT),y
				clc
				rts
				
.1				cmp #S.TCP.OPTIONS.FIN
				bne .8
				
				ldy #S.SOCKET.TCP.OPTIONS
				lda (ZPPtrSKT),y
				ora #S.TCP.OPTIONS.ACK	
				sta (ZPPtrSKT),y
				
				jsr TCP.OUT
				bcs .9

				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.CLOSING
				sta (ZPPtrSKT),y
								
.8				clc
.9				rts
*--------------------------------------
TCP.IN.JMP.FINWT2
				ldy #S.TCP.OPTIONS		only accept FIN packet
				lda (ZPFrameInPtr),y
				cmp #S.TCP.OPTIONS.FIN
				bne .8
				
				ldy #S.SOCKET.TCP.OPTIONS
				lda (ZPPtrSKT),y
				ora #S.TCP.OPTIONS.ACK	
				sta (ZPPtrSKT),y
				
				jsr TCP.OUT
				bcs .9

				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.TIMEWT
				sta (ZPPtrSKT),y
				
.8				clc
.9				rts
*--------------------------------------
TCP.IN.JMP.CLOSING
				ldy #S.TCP.OPTIONS		only accept ACK packet
				lda (ZPFrameInPtr),y
				cmp #S.TCP.OPTIONS.ACK
				bne .1
				
				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.TIMEWT
				sta (ZPPtrSKT),y
				
.1				clc
				rts
*--------------------------------------
TCP.IN.JMP.TIMEWT
*--------------------------------------
TCP.IN.JMP.CLOSED
				clc
				rts
*--------------------------------------
TCP.IN.SetDataInPtrAndLen
				ldy #S.IP.TOTAL.LENGTH+1
				lda (ZPFrameInPtr),y
				sec
				sbc #S.IP-S.ETH
				sta ZPDataInLen

				dey
				lda (ZPFrameInPtr),y
				sbc /S.IP-S.ETH
				sta ZPDataInLen+1
				
				ldy #S.TCP.DATAOFFSET
				lda (ZPFrameInPtr),y
				and #$F0				Get TCP Header len in DWORD
				lsr
				lsr
				sta TmpOffset

				lda ZPDataInLen
				sec
				sbc TmpOffset
				sta ZPDataInLen
				
				bcs .1
				dec ZPDataInLen+1
				
.1				lda ZPFrameInPtr
				clc
				adc #S.IP
				pha
				
				lda ZPFrameInPtr+1
				adc /S.IP
				tax
				
				pla
				clc
				adc TmpOffset
				bcc .2
				
				inx
				
.2				sta ZPDataInPtr
				stx ZPDataInPtr+1
				rts
*--------------------------------------
TCP.OUT			jsr SKT.GetTCB 

TCP.OUT.I		lda SKT.TCBCache+S.TCB.TOSEND+1
				ldy SKT.TCBCache+S.TCB.TOSEND
				
				bne .1
			
				tax
				bne .1
				
*	Y,A=0 : no data to send		
		
				ldy #S.SOCKET.TCP.OPTIONS
				lda (ZPPtrSKT),y
				bne TCP.OUT.SendOpt		a least an option...
				clc						No, data, no flag....exit
				rts
						
.1				cpy #K.TCP.MSS
				pha
				sbc /K.TCP.MSS			OUTDATA > MSS ?
				pla
				bcc .2					no....keep data len

				>LDYAI K.TCP.MSS		yes get only MSS
				
.2				jsr TCP.NewFrame
				bcs TCP.OUT.9

				jsr SKT.GetDataFromSktOut
								
				ldy #S.SOCKET.TCP.OPTIONS
				lda (ZPPtrSKT),y
				jsr TCP.OUT.Send
				
				bcs TCP.OUT.9
				
				lda SKT.TCBCache+S.TCB.SEQNUM+3
				clc
				adc ZPDataOutLen
				sta SKT.TCBCache+S.TCB.SEQNUM+3
				
				lda SKT.TCBCache+S.TCB.SEQNUM+2
				adc ZPDataOutLen+1
				sta SKT.TCBCache+S.TCB.SEQNUM+2
				bcc .80
				inc SKT.TCBCache+S.TCB.SEQNUM+1
				bne .80
				inc SKT.TCBCache+S.TCB.SEQNUM
				
.80				jmp SKT.StoreTCB
TCP.OUT.9		rts
*--------------------------------------
TCP.OUT.SendOpt	sta .1+1
				>LDYAI 0
				jsr TCP.NewFrame
				bcs TCP.OUT.9				

.1				lda #$ff
				
TCP.OUT.Send	ldy #S.TCP.OPTIONS
				sta (ZPFrameOutPtr),y
				bit #S.TCP.OPTIONS.ACK
				beq .11
				
				ldx #3
				ldy #S.TCP.ACK.NUMBER+3
				
.10				lda SKT.TCBCache+S.TCB.ACKNUM,x
				sta (ZPFrameOutPtr),y
				dey
				dex
				bpl .10
				bra .1
				
.11				ldy #S.TCP.ACK.NUMBER
				lda #0
				
.12				sta (ZPFrameOutPtr),y
				iny
				cpy #S.TCP.ACK.NUMBER+4
				bne .12
				
.1				ldx #3
				ldy #S.TCP.SEQ.NUMBER+3
				
.2				lda SKT.TCBCache+S.TCB.SEQNUM,x
				sta (ZPFrameOutPtr),y
				dey
				dex
				bpl .2
				
				ldy #S.TCP.WINDOW
				lda SKT.TCBCache+S.TCB.INFREE+1
				sta (ZPFrameOutPtr),y
				iny
				lda SKT.TCBCache+S.TCB.INFREE
				sta (ZPFrameOutPtr),y

				jsr FRM.SendIP
				bcs .9
				
				ldy #S.SOCKET.TCP.OPTIONS
				lda (ZPPtrSKT),y
				bit #S.TCP.OPTIONS.FIN
				beq .8
				
				ldy #S.SOCKET.TCP.STATUS
				lda #S.SOCKET.TCP.STATUS.FINWT1
				sta (ZPPtrSKT),y

.8				ldy #S.SOCKET.TCP.OPTIONS
				lda #0
				sta (ZPPtrSKT),y

				clc
.9				rts
*--------------------------------------
TCP.NewFrame	ldx #S.IP.PROTOCOL.TCP
				jsr FRM.NewIP
				bcs .9
				
				jsr SKT.SetFrameOutDstIP

				ldy #S.SOCKET.SRC.PORT
				lda (ZPPtrSKT),y
				tax
				iny
				lda (ZPPtrSKT),y
 				ldy #S.TCP.SRCPORT
				sta (ZPFrameOutPtr),y
				iny
				txa
				sta (ZPFrameOutPtr),y
				
				ldy #S.SOCKET.DST.PORT
				lda (ZPPtrSKT),y
				tax
				iny
				lda (ZPPtrSKT),y
 				ldy #S.TCP.DSTPORT
				sta (ZPFrameOutPtr),y
				iny
				txa
				sta (ZPFrameOutPtr),y
				
				ldy #S.TCP.DATAOFFSET
				lda #$50				Header size = 5 DWORDS
				sta (ZPFrameOutPtr),y
				
				ldy #S.TCP.WINDOW
				lda SKT.TCBCache+S.TCB.INFREE+1
				sta (ZPFrameOutPtr),y
				iny
				lda SKT.TCBCache+S.TCB.INFREE
				sta (ZPFrameOutPtr),y
				
				clc
.9				rts
*--------------------------------------
TCP.ComputeChecksum
				lda #0					RESET.TCP.CHECKSUM
				ldy #S.TCP.CHECKSUM
				sta (ZPFrameOutPtr),y
				iny
				sta (ZPFrameOutPtr),y
				
				>LDYA ZPFrameOutPtr
				>STYA ZPTmpPtr1
				
				lda ZPFrameOutLen
				sec
				sbc #S.IP-2
				sta ZPDataInLen
				
				lda ZPFrameOutLen+1
				sbc /S.IP-2
				sta ZPDataInLen+1
				
				clc
				
*				lda ZPDataInLen+1
*				adc #0					RESERVED (all zero)
				sta IP.CHECKSUM

				lda ZPDataInLen
				adc #S.IP.PROTOCOL.TCP
				sta IP.CHECKSUM+1
				
				ldy #S.IP.SRC
				
				ldx #4					4 words for SRC & DST IP
				
.10				lda (ZPFrameOutPtr),y
				adc IP.CHECKSUM
				sta IP.CHECKSUM
				iny
				lda (ZPFrameOutPtr),y
				adc IP.CHECKSUM+1
				sta IP.CHECKSUM+1
				iny
				dex
				bne .10
				
				ldy #S.IP
				
				lda ZPDataInLen
				eor #$ff
				tax
				lda ZPDataInLen+1
				eor #$ff
				
				pha
				
.1				inx
				bne .11
				pla
				inc
				beq .8
				
				pha
				
.11				lda (ZPTmpPtr1),y
				adc IP.CHECKSUM
				sta IP.CHECKSUM

				iny
				bne .20
				inc ZPTmpPtr1+1
				
.20				inx
				bne .2
				pla
				inc
				beq .7
				
				pha

.2				lda (ZPTmpPtr1),y

				adc IP.CHECKSUM+1
				sta IP.CHECKSUM+1
				
				iny
				bne .1
				inc ZPTmpPtr1+1
				bra .1
				
.7				adc IP.CHECKSUM+1		A=0 from beq .7
				sta IP.CHECKSUM+1
				
.8				ldy #S.TCP.CHECKSUM
				lda IP.CHECKSUM
				adc #0					Don't forget to add last carry!!!
				eor #$FF
				sta (ZPFrameOutPtr),y
				iny
				lda IP.CHECKSUM+1
				adc #0					Don't forget to add last carry!!!
				eor #$FF
				sta (ZPFrameOutPtr),y
				rts
*--------------------------------------
MAN
SAVE /A2OSX.SRC/LIB/LIBTCPIP.S.TCP
LOAD /A2OSX.SRC/LIB/LIBTCPIP.S
ASM