A2osX/LIB/LIBTCPIP.S.UDP.txt

PR#3
PREFIX /A2OSX.SRC
LOMEM $A00
INC 1
AUTO 6
				.LIST OFF	
*--------------------------------------
UDP.IN			jsr IP.FillTmpSocketSrcDst
				
				ldy #S.UDP.SRCPORT
				lda (ZPFrameBase),y
				sta TmpSocket+S.SOCKET.DST.PORT+1
				iny
				lda (ZPFrameBase),y
				sta TmpSocket+S.SOCKET.DST.PORT
				
				ldy #S.UDP.DSTPORT
				lda (ZPFrameBase),y
				sta TmpSocket+S.SOCKET.SRC.PORT+1
				iny
				lda (ZPFrameBase),y
				sta TmpSocket+S.SOCKET.SRC.PORT
				
				>LDYA L.SKT.TABLE
				>STYA ZPPtrSKT
				
				ldx #0
				
.3				lda (ZPPtrSKT)
				beq .7
				cmp #S.SOCKET.SOCK.DGRAM
				bne .7
				
				ldy #S.SOCKET.SRC.ADDR
				lda (ZPPtrSKT),y		SOCKET.SRC.ADDR=0.0.0.0 ?
				bne .41					
				ldy #S.SOCKET.SRC.PORT	yes, do not check if IP match
				
.4				lda (ZPPtrSKT),y
.41				cmp TmpSocket,y
				bne .7
				iny
				cpy #S.SOCKET.DST.ADDR
				bne .4
				
				lda (ZPPtrSKT),y		SOCKET.DST.ADDR=FF.FF.FF.FF ?
				cmp #$FF
				bne .51
				ldy #S.SOCKET.DST.PORT	yes, do not check if IP match

.5				lda (ZPPtrSKT),y
.51				cmp TmpSocket,y
				bne .7
				iny
				cpy #S.SOCKET.DST.PORT+2
				bne .5
				
				lda hFrameIn
				jsr SKT.AddToQueueA
				bcs .9					Q full, discard...
				
				rts						DO NOT Discard this queued frame
				
.7				lda ZPPtrSKT
				clc
				adc #S.SOCKET
				sta ZPPtrSKT
				bcc .8
				inc ZPPtrSKT+1
				
.8				inx
				cpx #K.SKTTABLE.SIZE
				bne .3
				
.9				lda hFrameIn
				>SYSCALL FreeMemA
				rts
*--------------------------------------
UDP.ComputeChecksum
				lda #0					RESET.TCP.CHECKSUM
				ldy #S.UDP.CHECKSUM
				sta (ZPFrameBase),y
				iny
				sta (ZPFrameBase),y
				
				>LDYA ZPFrameBase
				>STYA ZPTmpPtr1
				
				lda ZPFrameLen
				sec
				sbc #S.IP-2
				sta ZPDataLen
				
				lda ZPFrameLen+1
				sbc /S.IP-2
				sta ZPDataLen+1
				
				clc
				
				ldy #S.UDP.LENGTH
				lda (ZPFrameBase),y
*				adc #0					RESERVED (all zero)
				sta IP.CHECKSUM

				iny
				lda (ZPFrameBase),y
				adc #S.IP.PROTOCOL.UDP
				sta IP.CHECKSUM+1
				
				ldy #S.IP.SRC
				
				ldx #4					4 words for SRC & DST IP
				
.10				lda (ZPFrameBase),y
				adc IP.CHECKSUM
				sta IP.CHECKSUM
				iny
				lda (ZPFrameBase),y
				adc IP.CHECKSUM+1
				sta IP.CHECKSUM+1
				iny
				dex
				bne .10
				
				ldy #S.IP
				
.1				jsr DecDataLen
				beq .8
				
				lda (ZPTmpPtr1),y
				adc IP.CHECKSUM
				sta IP.CHECKSUM

				iny
				bne .20
				inc ZPTmpPtr1+1
				
.20				jsr DecDataLen
				bne .2
				lda #0
				bra .21

.2				lda (ZPTmpPtr1),y

.21				adc IP.CHECKSUM+1
				sta IP.CHECKSUM+1
				
				iny
				bne .1
				inc ZPTmpPtr1+1
				bra .1
				
.8				ldy #S.UDP.CHECKSUM
				lda IP.CHECKSUM
				adc #0					Don't forget to add last carry!!!
				eor #$FF
				sta (ZPFrameBase),y
				iny
				lda IP.CHECKSUM+1
				adc #0					Don't forget to add last carry!!!
				eor #$FF
				sta (ZPFrameBase),y
				rts
*--------------------------------------
MAN
SAVE LIB/LIBTCPIP.S.UDP
LOAD LIB/LIBTCPIP.S
ASM