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; Copyright (c) 1983 by
; DIGITAL EQUIPMENT CORPORATION, Maynard, Massachusetts 01754
;
; This software is furnished under a license and may be used and  copied
; only  in  accordance  with  the  terms  of  such  license and with the
; inclusion of the above copyright notice.  This software or  any  other
; copies  thereof may not be provided or otherwise made available to any
; other person.  No title to and ownership of  the  software  is  hereby
; transferred.
;
; The information in this software is subject to change  without  notice
; and  should  not  be  construed  as  a commitment by Digital Equipment
; Corporation.
;
; Digital assumes no responsibility for the use or  reliability  of  its
; software on equipment which is not supplied by Digital.

	SALL
	TITLE	X29TRP	Trap And Reject Incoming X.29 Calls
	SUBTTL	Data Declarations

	SEARCH	X25SYM
	SEARCH	MONSYM,MACSYM

; Accumulators

S1=1					;Scratch ACs
S2=2
S3=3
S4=4
T1=5					;Temporary ACs
T2=6
SP=17

; Push Down Stack

SIZE=^D200
STACK:	BLOCK	SIZE

; X.25 Access Argument Blocks

BUFFER:	BLOCK	1			;Virtual circuit data buffer
FILJFN:	BLOCK	1			;Reject text file JFN
FILSIZ:	BLOCK	1			;Reject text file length
PKTSIZ:	BLOCK	1			;Virtual circuit packet size
STATE:	BLOCK	1			;Port state

ARGBLK:	BLOCK	^D10			;Argument block
WSPACE:	BLOCK	.PBSIZ+<^D128/4>	;Working area for the X.25 library

; Interrupt System Storage Definitions

CH.X25=0				;Interrupt channel number
SAVEPC:	BLOCK	1			;Location for saved PC
LEVTAB:	SAVEPC				;Interrupt level table
	REPEAT	2,<0>
CHNTAB:	1,,SRVCKT			;Interrupt handler entry
	REPEAT	^D35,<0>		;Unused channels have 0

	SUBTTL	Main Program

START:	RESET				;Reset the world
	MOVE	SP,[IOWD SIZE,STACK]	;Set up push down stack
SETUP:	CALL	PSIINI			;Initialize interrupt system
	CALL	X25WIC			;Set up incoming call port
	WAIT				;Dismiss the process

PSIINI:	MOVEI	S1,.FHSLF		;Current process
	MOVE	S2,[LEVTAB,,CHNTAB]	;Interrupt table
	SIR
	EIR				;Enable system
	MOVE	S2,[1B<CH.X25>]		;Activate channel
	AIC
	RET				;Return

X25WIC:	MOVEI	T1,XS%UND
	MOVEM	T1,STATE		;Set port state to UNDEFINED
	SETZM	ARGBLK			;Initialize the argument block
	MOVE	T1,[ARGBLK,,ARGBLK+1]
	BLT	T1,ARGBLK+^D9
	MOVE	T1,[CH.X25,,WSPACE]
	MOVEM	T1,ARGBLK		;Interrupt channel and work area
	MOVE	T1,[POINT 7,[ASCIZ/SRV:.X29TRAP/]]
	MOVEM	T1,ARGBLK+2		;SRV: file descriptor
	MOVEI	S1,ARGBLK		;Pass access argument block
	CALL	X%WIC##			;Wait Incoming Call
	MOVE	T1,ARGBLK+1		;Get return code
	CAIE	T1,XC%SUC		;Is it successful ?
	HALTF				;No, terminate
	MOVEI	T1,XS%LSN		;Yes,
	MOVEM	T1,STATE		;Change port state to LISTENING
	RET				;Return

SRVCKT:	SETZM	ARGBLK+1		;Initialize argument block entries
	MOVE	T1,[ARGBLK+1,,ARGBLK+2]
	BLT	T1,ARGBLK+^D9
	MOVEI	S1,ARGBLK		;Pass access argument block
	CALL	X%RPS##			;Check current port status
	HRRZ	T1,ARGBLK+3		;Get current packet size
	MOVEM	T1,PKTSIZ		;Save it
	MOVE	T1,ARGBLK+1		;Get return code
	CAIE	T1,XC%SUC		;Is it successful ?
	 JRST	X25TPA			;No, terminate
	MOVE	T1,STATE		;Get old port state
	HRRZ	T2,ARGBLK+2		;Get new port state
	CAIN	T1,XS%LSN		;From LISTENING state
	 JRST	[CAIN	T2,XS%LSN	;Remain in LISTENING state
		  JRST	SRVCKT		;Check the port state again
		 CAIE	T2,XS%CAD	;Changed to CALLED state ?
		  JRST	X25TPA		;No, terminate port
		 JRST	X25AIC]		;Accept incoming call
	JRST	X25TPA			;Don't want to handle other states

X25AIC:	MOVSI	S1,(GJ%OLD+GJ%SHT)	;Get reject text
	HRROI	S2,[ASCIZ/SYSTEM:X29REJ.TXT/]
	GTJFN
	 JRST	X25TPA			;No reject text, terminate circuit
	MOVE	S2,[7B5+OF%RD]
	OPENF
	 JRST	X25TPA			;No reject text, terminate circuit
	MOVEM	S1,FILJFN		;Save file JFN
	SIZEF				;Get file length
	 JRST	X25TPA			;Something is wrong, terminate circuit
	MOVEM	S2,FILSIZ		;Save file length
	SETZM	ARGBLK+1		;Yes, Initialize argument block entries
	MOVE	T1,[ARGBLK+1,,ARGBLK+2]
	BLT	T1,ARGBLK+^D9
	MOVEI	S1,ARGBLK		;Accept incoming call unconditionally
	CALL	X%AIC##
	MOVE	T1,ARGBLK+1		;Get return code
	CAIE	T1,XC%SUC		;Is it successful ?
	 JRST	X25TPA			;No, terminate
	MOVEI	T1,XS%RUN		;Yes,
	MOVEM	T1,STATE		;Change port state to RUNNING
	MOVEI	S1,ARGBLK		;Get argument block
	SETZM	ARGBLK+2		;Reset buffer length and indicators
	MOVE	T1,FILJFN		;Get reject text file JFN
	MOVEM	T1,ARGBLK+3		;Make it the data pointer

TXTOUT:	MOVE	T1,FILSIZ		;Get file length
	CAIG	T1,0			;Anything left to send
	 JRST	REJECT			;No, then clear the circuit
	MOVE	T2,PKTSIZ		;Get packet size
	SUB	T1,T2			;Calculate the remaining length
	CAIG	T1,0			;Is this the last packet to send
	 JRST	[MOVE	T2,FILSIZ	;Yes
		 JRST	.+1]		;Remaining file length is packet length
	MOVEM	T1,FILSIZ		;Save remaining file length
	HRRZM	T2,ARGBLK+2		;Set packet length
	CALL	X%SDM##			;Send data
	MOVE	T1,ARGBLK+1		;Get return code
	CAIE	T1,XC%SUC		;Is it successful ?
	 JRST	X25TPA			;No, terminate circuit
	JRST	TXTOUT			;Send the remaining length

REJECT:	MOVE	S1,FILJFN		;Get reject text file JFN
	CLOSF				;Close file
	 JFCL	0
	SETZM	ARGBLK+2		;Reset packet length and indicators
	MOVEI	T1,1			;Send one byte
	HRRM	T1,ARGBLK+2
	MOVE	T1,[XM%QUA]		;Set qualified bit
	IORM	T1,ARGBLK+2
	MOVE	T1,[1B7]
	MOVEM	T1,BUFFER
	MOVE	T1,[POINT 8,BUFFER]	;Get pointer to data
	MOVEM	T1,ARGBLK+3
	CALL	X%SDM##			;Send CLEAR INVITATION to PAD
	MOVE	T1,ARGBLK+1
	CAIE	T1,XC%SUC		;Is it successful ?
	 JRST	X25TPA			;No terminate circuit
	DEBRK

X25TPA:	MOVEI	S1,ARGBLK
	CALL	X%TPA##			;Terminate port access
	CIS				;Clear interrupt system
	JRST	SETUP			;Go back to set it up again
	END	START			;End Of Program

; Local Modes:
; Mode:MACRO
; Auto Save Mode:2
; Comment Column:40
; Comment Rounding:+1
; End: