/****************************************************************************
   
    OS/A65 Version 2.0.0
    Multitasking Operating System for 6502 Computers

    Copyright (C) 1989-1998 Andre Fachat 

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

****************************************************************************/

/*
 * This file is a TCP implementation for 6502 computer
 *
 * it exports:
 *	udpinit		- init TCP
 *	udprx		- gets incoming packets
 *
 */

/* #define	DEBUGUDP */

#ifdef DEBUGUDP
#define	DBUDP(a)	DB(a)
#else
#define	DBUDP(a)
#endif

	.(

&&udpinit .(
	clc
	rts
	.)


&&udprx .(

	jsr getpinfo
	bcc piok
	DBUDP("getpi error in udprx^m^j")
	rts
piok
	ldy #6
	lda (pd),y
	iny
	ora (pd),y
	beq udpok	; no check

#if 0
	jsr ip2tcp

#if 0 /*def DEBUGTCP*/
DB("TCP check: pd=")
lda pd+1: jsr EHexout: lda pd: jsr EHexout
DB(", pdl=")
lda pdl+1: jsr EHexout: lda pdl: jsr EHexout
DB(", pp=")
lda pp+1: jsr EHexout: lda pp: jsr EHexout
DB(", ppl=")
lda ppl+1: jsr EHexout: lda ppl: jsr EHexout
jsr ECrlfout
#endif

	lda pdl
	ldy pdl+1
	ldx #pd
	jsr checksum3

	php
	lda #8
	sta phl
	jsr tcp2ip
	plp

#if 0 /*def DEBUGTCP*/
php
pha
txa
pha
DB("TCP Checksum=")
pla
tay
jsr EHexout
pla
pha
jsr EHexout
jsr ECrlfout
tya
tax
pla
plp
#endif
	bcc udpok
#endif

tdisc_check
        DB("Packet discarded: UDP checksum^m^j")
&tdisc	ldx pslot
	bmi illtd
	jsr bfree
	lda #<-1
	sta pslot
	clc
	rts
illtd	DBUDP("tdisc with illegal slot!^m^j")
	sec
	rts
	

udpok	/* here we have a valid UDP packet in (pd),0-pdl. */
/*
DB("tcpok pp=")
lda pp+1:jsr EHexout:lda pp:jsr EHexout
jsr ECrlfout
*/
	DBUDP("UDP port unreachable packet!^m^j")

	; jsr exports

	lda phl
	ldx pslot
	jmp uporterr
	.)

	.)