COMMENT ⊗   VALID 00015 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	TITLE TELSER
C00004 00003	Data area
C00006 00004	TELNET protocol codes
C00009 00005	Interrupt server
C00011 00006	Start of program
C00013 00007	Log this connection
C00015 00008	Initialize the connection
C00017 00009	Network input interrupt
C00019 00010	PTY input interrupt
C00020 00011	IAC server
C00022 00012	Protocol command routines
C00024 00013	 IAC DO/DONT
C00027 00014	 IAC WILL/WONT
C00028 00015	Subroutines
C00031 ENDMK
C⊗;
TITLE TELSER
SUBTTL Definitions

; Mark Crispin, SU-AI, March 1978

; Assembly switches

IFNDEF SVRSKT,SVRSKT==27		; default listen socket
IFNDEF LOKTMO,LOKTMO==5			; # of 15-second frobs of lock timeout
IFNDEF PDLLEN,PDLLEN==50		; stack length

; AC definitions.  0→3 are used by NETWRK

X=4 ? A=5 ? B=6 ? P=17

; Macro to send a TELNET command

DEFINE TELCMD CMDLST
 OUTSTR [ASCIZ/⊗!CMDLST!*
/]
 IRPS CMD,,CMDLST
  MOVEI CMD
  PUSHJ P,NETOCH
 TERMIN
 PUSHJ P,NETSND
TERMIN

; SAIL system bit definitions

INTPTO==001000,,			; PTY interrupt
INTCLK==000200,,			; clock interrupt
DMLIN== 040000,,			; terminal is a Datamedia
ECHARR==010000,,			; echo controls with uparrow
IMPBIT==001000,,			; IMP TTY
FCS==   000020,,			; full character set mode
TBXPND==000010,,			; expand tabs to spaces
FULTWX==000004,,			; no echo
TLKRNG==000001,,			; TALKing
SUBTTL Data area

; TTYSET command words

ECHON:	002400,,(FULTWX)		; echo on
ECHOFF:	001400,,(FULTWX)		; echo off
GAGOFF:	024400,,0			; gag off

; Terminal location string

TERMID:	'TERMID

CORBEG==.				; start of initialized core storage

TERSTR:	BLOCK 10.			; console location string

; Interrupt flags

PTINTP:	BLOCK 1				; -1 → PTI interrupt
NTINTP:	BLOCK 1				; -1 → NTI interrupt
NTOINP:	BLOCK 1				; -1 → INS interrupt

; Protocol flags

NETCMP:	BLOCK 1				; -1 → IAC in progress

IRPS OPT,,WILL WONT DO DONT
 OPT!P:	BLOCK 1				; -1 → option in effect
TERMIN

RCBINP:	BLOCK 1				; -1 → receiving binary
TRBINP:	BLOCK 1				; -1 → transmitting binary
ECHOP:	BLOCK 1				; -1 → remote echoing
SUPGAP:	BLOCK 1				; -1 → suppressing GA

; Other flags

TIPP:	BLOCK 1				; -1 → on a TIP
NODETP:	BLOCK 1				; -1 → don't detach this guy
NEWLNP:	BLOCK 1				; -1 → starting newline
LFFLSP:	BLOCK 1				; -1 → PTISER's LF flush kludge

; Other storage

TTYLIN:	BLOCK 1				; line number of PTY
IDLTIM:	BLOCK 1				; idle time in 15-second units
WHOBUF:	BLOCK 22			; wholine buffer
PDL:	BLOCK PDLLEN			; stack

COREND==.-1				; end of initialized storage
SUBTTL TELNET protocol codes

DEFINE TPC CODE
 CODE
 IRPS NAME,,CODE
  [ASCIZ/NAME/]
 .ISTOP
 TERMIN
TERMIN

; Protocol codes

TPLTAB:
 TPC SE==360				; subnegotiation end
 TPC NOP==361				; no-op
 TPC DM==362				; data mark
 TPC BRK==363				; break key
 TPC IP==364				; interrupt process
 TPC AO==365				; abort output
 TPC AYT==366				; are you there?
 TPC EC==367				; erase character
 TPC EL==370				; erase line
 TPC GA==371				; go ahead
 TPC SB==372				; subnegotiation
 TPC WILL==373				; sender will do
 TPC WONT==374				; sender won't do
 TPC DO==375				; receiver asked to do
 TPC DONT==376				; receiver must not do
 TPC IAC==377				; interpret as command
TPLMIN==400-<.-TPLTAB>

; WILL/WONT/DO/DONT codes

WDOTAB:
 TPC TRNBIN==0				; transmit binary
 TPC ECHO==1				; echo
 TPC RCP==2				; reconnect
 TPC SUPRGA==3				; suppress GA
 TPC NAMS==4				; negotiate approx. message size
 TPC STATUS==5				; status option
 TPC TIMMRK==6				; timing mark
 TPC RCTE==7				; remote controlled trans/echo
 TPC NAOL==10				; negotiate output line width
 TPC NAOP==11				; negotiate page size
 TPC NAOCRD==12				; negotiate output CR
 TPC NAOHTS==13				; negotiate output horizontal tab stops
 TPC NAOHTD==14				; negotiate output HT
 TPC NAOFFD==15				; negotiate output FF
 TPC NAOVTS==16				; negotiate output vertical tab stops
 TPC NAOVTD==17				; negotiate output VT
 TPC NAOLFD==20				; negotiate output LF
 TPC EXTASC==21				; Tovar's idea of extended ASCII
 TPC LOGOUT==22				; logout option
 TPC BM==23				; byte macro
 TPC DET==24				; data entry terminal option
 TPC SUPDUP==25				; SUPDUP (not TELNET) protocol
WDOMAX==.-WDOTAB-1

EXOPL==377				; extended options (great idea Postel)
SUBTTL Interrupt server

;  Interrupts only set flags which the main program (normally in INTW⊗
; state) looks at.

INTSER:	SKIPN X,JOBCNI			; get interrupt status
	 JRST 4,.-1
	TLNE X,(INTPTO)			; PTY int
	 SETOM PTINTP
	TLNE X,(INTCLK)			; CLK int
	 JRST CLKSER
	TLNE X,(INTINP)			; NTI int
	 SETOM NTINTP
	TLNE X,(INTIMS)			; status change
	 JRST INTDIE
	TLNE X,(INTINR)
	 OUTSTR [ASCIZ/*INR*
/]
	TLNN X,(INTINS)			; IMP INS int
	 DISMIS
	SOS NTOINP
	OUTSTR [ASCIZ/*INS*
/]
	DISMIS

; Service clock interrupt

CLKSER:	AOSE IDLTIM			; bump idle time
	 JRST CLKSR1
	UNLOCK				; idle timeout; unlock
	MOVE TTYLIN
	PTGETL
	TLNE 1,(TLKRNG)			; TALKing?
	 JRST CLKSR1			; don't kill him if so!
	TTYJOB
	JUMPN CLKSR1
	SETOM NODETP			; forget about detaching
	INTMSK [0]			; no more interrupts
	DEBREAK				; out of interrupt level
	TLNN 1,(DMLIN)
	 JRST DIEDIE			; not a DM, just die
	MOVEI ↑X			; cancel modes
	PUSHJ P,NETOCH
	MOVEI ↑]			; scroll on
	PUSHJ P,NETOCH
	PUSHJ P,NETSND			; cursor to bottom of screen and roll on
	JRST DIEDIE
CLKSR1:	MOVEI 2				; check connection status
	MTAPE NET,
	TLNN 1,(CLSS\CLSR)		; send side gronked?
	 TLNE 2,(CLSS\CLSR)		; receive side?
	  JRST INTDIE
	DISMIS
SUBTTL Start of program

TELSER:	JFCL
	RESET
	MOVE ['TELSER]
	SETNAM
	SETZM CORBEG
	MOVE [CORBEG,,CORBEG+1]
	BLT COREND
	MOVE P,[PDL(-PDLLEN)]
	MOVEI [DEBREAK ? EXIT]
	MOVEM JOBAPR
	CLKINT 5.*60.*60.		; must die if around too long
	OUTSTR [ASCIZ/TELSER started
/]

; Listen for a connection on our socket

	SETOM NODETP			; don't try to detach
	MOVEI SVRSKT
	MOVEM LSNSKT
	PUSHJ P,LISTEN

; Set up interrupts

	MOVEI INTSER
	MOVEM JOBAPR			; set up server location
	CLKINT 60.*15.			; start slow ticking clock
	MOVSI (INTPTO\INTCLK\INTINR\INTINS\INTIMS\INTINP)
	INTENB				; turn on interrupts

; Set up terminal id for interested spies

	MOVEI TERMID
	MOVEM JOBVER
SUBTTL Log this connection

	OUTSTR [ASCIZ/Connected to /]
	PUSHJ P,MAPHST			; map in host table
	MOVE HOST
	PUSHJ P,HSTNUM			; get HDB
	 JFCL				; sorry about errors
	MOVEI A,(1)			; host name
	HRLI A,440700
	SKIPA X,[440700,,TERSTR]
CPYHST:	 IDPB B,X
	ILDB B,A
	JUMPN B,CPYHST
	HLRZ A,1			; pointer to system name
	MOVE B,(A)			; get system name
	MOVE A,FSOCKT			; and ICP socket
	CAMN B,[ASCII/TIP/]		; on a TIP?
	 TRNE A,177774			; just paranoia; make sure a TIP port
	  JRST NOTTIP
	SETOM TIPP
	MOVEI B,"#
	IDPB B,X
	LSH A,-16.
	IDIVI A,8.			; ports are octal
	JUMPE A,1DIGTP
	ADDI A,"0 ? IDPB A,X
1DIGTP:	ADDI B,"0 ? IDPB B,X
NOTTIP:	PUSHJ P,SETANM			; set our alias name
	PUSHJ P,UNMHST			; map out the host table
	OUTSTR TERSTR
	OUTSTR [ASCIZ/
/]
SUBTTL Initialize the connection

; Initial protocol commands

	TELCMD [IAC WILL ECHO IAC WILL SUPRGA]
	SETOM ECHOP ? SETOM SUPGAP

; Greet the user

	MOVEI X,[ASCIZ/SU A.I. Lab KL-10
/]
	PUSHJ P,SNDMSG

; Get a PTY, keep its number in A

	PTYGET A
	 JRST [	MOVEI X,[ASCIZ/All network ports in use.
/]
		PUSHJ P,SNDMSG
		PUSHJ P,CLOSER
		JRST SUICID]
	HRRZM A,TTYLIN			; dumb interrupts
	MOVSI (A)
	IRPS FOO,,ECHON ECHOFF GAGOFF
	 IORM FOO
	TERMIN
	MOVSI B,(ECHARR\IMPBIT\FCS\TBXPND)
	PTSETL A			; set initial bits
	HRROI GAGOFF
	TTYSET				; turn GAG bit off
	MOVEI B,↑M
	PTWR1W A

; Final initialization

	MOVNI 1,LOKTMO
	MOVEM 1,IDLTIM			; initialize lock timeout
	LOCK				; keep response good
	SETZM NODETP			; okay to detach jobs now
	JRST NTISER			; check network input

; Main program loop

MAINL:	IWAIT				; wait for an interrupt
MAINL0:	AOSG NTINTP			; net input?
	 JRST NTISER
	AOSG PTINTP			; PTY input?
	 JRST PTISER
	JRST MAINL			; back to sleep for us
SUBTTL Network input interrupt

NTISER:	PUSHJ P,NETICH			; get character from the network
	 JRST MAINL0			; network input buffer empty
	SKIPL IDLTIM
	 LOCK
	MOVNI 1,LOKTMO
	MOVEM 1,IDLTIM			; reset idle time
	AOSG NETCMP			; IAC in progress?
	 JRST IACSER
	IRPS OPT,,WILL WONT DO DONT
	 AOSG OPT!P
	  JRST OPT!SR
	TERMIN
	CAIN IAC			; network command?
	 JRST [	SETOM NETCMP		; remember that one is coming
		JRST NTISER]
	AOSE NEWLNP			; flush second half of NL?
	 JRST NTISR2
	SKIPE TIPP			; TIPs send neither LF's nor
	 SKIPN RCBINP			; nulls in binary mode (but Tenices do)
	  JUMPE NTISER			; yah, flush nulls or
	CAIN ↑J				; LFs
	 JRST NTISER
NTISR2:	CAIE ↑M				; CR?
	 JRST NTISR1
	SKIPN ECHOP			; if in local mode
	 SETOM LFFLSP			; kludge to prevent system echo of LF's
	SETOM NEWLNP			; maybe flush an LF
NTISR1:	SKIPGE NTOINP			; still in flushify mode?
	 JRST NTISER			; too bad
	MOVE B,
PTYSND:	PTWR1S A			; send character to PTY
	 JRST [	PUSHJ 17,NETINS		; buffer full, send INS
		TELCMD [IAC AO IAC DM]	; tell user to flush output
		MOVEI ↑G		; bell
		PUSHJ 17,NETOCH
		PUSHJ 17,NETSND		; output it
		JRST NTISER]
	JRST NTISER			; try for more user characters
SUBTTL PTY input interrupt

PTISER:	PTRD1S A			; get a character from the PTY
	 JRST MAINL0			; PTY input buffer empty
	SKIPGE IDLTIM
	 LOCK
PTISR1:	MOVNI 1,LOKTMO
	MOVEM 1,IDLTIM			; reset idle time
	MOVE B
	ANDI 377			; flush funny 400 bit
	CAIN ↑J				; LF?  (someday remove this kludge)
	 AOSE LFFLSP			; yes, second part of NL?
	  PUSHJ P,NETOCH		; send character to net
	CAIN IAC			; IAC needs quoting
	 PUSHJ P,NETOCH
	PTRD1S A			; try for more while here
	 CAIA
	  JRST PTISR1			; more coming
	PUSHJ P,NETSND			; force buffer out
	JRST MAINL0			; scan the world again
SUBTTL IAC server

IACSER:	OUTSTR [ASCIZ/*IAC /]
	CAIGE TPLMIN			; big enough?
	 JRST @RNDMSG
	MOVE 1,
	OUTSTR @TPLTAB-TPLMIN(1)
	CAIE IAC
	 CAIGE WILL
	  OUTSTR [ASCIZ/*
/]
	CAIL TPLMIN
	 XCT PRSTAB-TPLMIN(1)
	JRST NTISER

DEFINE NC CODE,SERVER
 IFN .+TPLMIN-PRSTAB-CODE,.ERR Lossage at CODE
 SERVER
TERMIN

PRSTAB:					; Protocol command server table

NC SE,[JRST NTISER]
NC NOP,[JRST NTISER]
NC DM,[AOS NTOINP]
NC BRK,[JRST HALTJB]
NC IP,[JRST HALTJB]
NC AO,[JRST ORESET]
NC AYT,[JRST WHOLIN]
NC EC,[JRST DELCHR]
NC EL,[JRST DELLIN]
NC GA,[JRST NTISER]
NC SB,[JRST NTISER]
NC WILL,[SETOM WILLP]
NC WONT,[SETOM WONTP]
NC DO,[SETOM DOP]
NC DONT,[SETOM DONTP]
NC IAC,[JRST NTISR1]
SUBTTL Protocol command routines

; IAC IP/IAC BRK

HALTJB:	MOVEI B,[.BYTE 9 ? 600 ? 600 ? 0]; CALL
	PTWRS9 A
	JRST NTISER

; IAC AO

ORESET:	MOVEI B,↑O
	PTWR1W A
	OUTSTR [ASCIZ/⊗INS*
/]
	PUSHJ P,NETINS			; send SYNCH
	TELCMD [IAC DM]
	JRST NTISER

; IAC AYT

WHOLIN:	HRROI WHOBUF			; system who-line
	WHO
	SKIPA X,[440700,,WHOBUF]
WHOLN1:	 PUSHJ P,NETOCH
	ILDB X
	JUMPN WHOLN1
	MOVE TTYLIN
	TTYJOB
	JUMPE WHOLN3
	HRL
	HRRI WHOBUF
	WHO
	SKIPA X,[440700,,WHOBUF]
WHOLN2:	 PUSHJ P,NETOCH
	ILDB X
	JUMPN WHOLN2
WHOLN3:	PUSHJ P,NETSND
	JRST NTISER

; IAC EC/IAC EL

DELCHR:	SKIPA B,[177]			; rubout
DELLIN:	 MOVEI B,↑U			; control-U
	JRST PTYSND
; IAC DO/DONT

DOSR:	PUSHJ P,OPTMSG
	CAIN TRNBIN			; binary from host
	 JRST [	SKIPE TRBINP		; catch protocol loops
		 JRST NTISER
		SETOM TRBINP
		TELCMD [IAC WILL TRNBIN]
		JRST NTISER]
	CAIN ECHO			; remote echo (what a win!)
	 JRST [	HRROI ECHON
		TTYSET
		SKIPE ECHOP		; catch protocol loops
		 JRST NTISER
		SETOM ECHOP
		TELCMD [IAC WILL ECHO]
		JRST NTISER]		; command, we always accept it
	CAIN SUPRGA			; suppress GA?
	 JRST [	SKIPE SUPGAP		; command or reply?
		 JRST NTISER
		SETOM SUPGAP
		TELCMD [IAC WILL SUPRGA]
		JRST NTISER]
	CAIN LOGOUT			; hairy MRC LOGOUT option?
	 JRST [	SETOM NODETP
		TELCMD [IAC WILL LOGOUT]; we may be the only place that has it!
		MOVEI X,[ASCIZ/Bye
/]
		PUSHJ P,SNDMSG
		JRST SUICID]

; Not an option we like, refuse it

	PUSH P,
	OUTSTR [ASCIZ/⊗IAC WONT/]
	MOVEI IAC
	PUSHJ P,NETOCH
	MOVEI WONT
	PUSHJ P,NETOCH
	POP P,
	PUSHJ P,OPTMSG
	PUSHJ P,NETOCH
	PUSHJ P,NETSND
	JRST NTISER

DONTSR:	PUSHJ P,OPTMSG
	CAIN TRNBIN
	 JRST [	SKIPN TRBINP
		 JRST NTISER
		SETZM TRBINP
		TELCMD [IAC WONT TRNBIN]
		JRST NTISER]
	CAIN ECHO
	 JRST [	HRROI ECHOFF
		TTYSET
		SKIPN ECHOP
		 JRST NTISER
		SETZM ECHOP		; back to lossage
		TELCMD [IAC WONT ECHO]
		JRST NTISER]
	CAIN SUPRGA
	 SKIPL SUPGAP
	  JRST NTISER			; protocol violator
	SETZM SUPGAP
	TELCMD [IAC WONT SUPRGA]
	JRST NTISER			; loser
; IAC WILL/WONT

WILLSR:	PUSHJ P,OPTMSG
	CAIN TRNBIN			; binary to host
	 JRST [	SKIPE RCBINP		; catch protocol loops
		 JRST NTISER
		SETOM RCBINP
		TELCMD [IAC DO TRNBIN]
		JRST NTISER]

; Not an option we like, refuse it

	PUSH P,
	OUTSTR [ASCIZ/⊗IAC DONT/]
	MOVEI IAC
	PUSHJ P,NETOCH
	MOVEI DONT
	PUSHJ P,NETOCH
	POP P,
	PUSHJ P,OPTMSG
	PUSHJ P,NETOCH
	PUSHJ P,NETSND
	JRST NTISER


WONTSR:	PUSHJ P,OPTMSG
	CAIN TRNBIN
	 SKIPN RCBINP
	  JRST NTISER
	SETZM RCBINP
	TELCMD [IAC DONT TRNBIN]
	JRST NTISER
SUBTTL Subroutines

; WILL/WONT/DO/DONT option message

OPTMSG:	CAIN EXOPL
	 JRST [	OUTSTR [ASCIZ/ EXOPL*
/]
		POPJ P,]
	OUTCHR [" ]
	CAILE WDOMAX
RNDMSG:	 JRST [	IDIVI 100
		ADDI "0
		OUTCHR
		IDIVI 10
		ADDI 1,"0
		OUTCHR 1
		ADDI 2,"0
		OUTCHR 2
		OUTSTR [ASCIZ/*
/]
		POPJ P,]
	MOVE 1,
	OUTSTR @WDOTAB(1)
	OUTSTR [ASCIZ/*
/]
	POPJ P,

; Send a message, b.p. in X

SNDMSG:	TLOA X,440700			; set up b.p.
MSGLUP:	 PUSHJ P,NETOCH
	ILDB X
	JUMPN MSGLUP			; continue until a null hit
	JRST NETSND

; Here to suicide on network errors or idle timeout

INTDIE:	INTMSK [0]			; no more interrupts
	DEBREAK				; out of interrupt level
SUICID:	OUTSTR [ASCIZ/Connection closed.
/]
	SKIPE NODETP
	 JRST DIEDIE			; logout the guy
	MOVE A,TTYLIN
	TTYJOB A,
	JUMPE A,DIEDIE
	MOVE A,TTYLIN
	MOVEI B,7
	PTJOBX A			; clear PTY's input buffer
	PTRD1S A			; slurp up stuff in buffer
	 CAIA
	  JRST .-2
	MOVEI B,[.BYTE 9 ? 600 ? 600 ? "D ? "E ? "T ? "A ? "C ? "H ? ↑M ? ↑J ? 0]
	PTWRS9 A
	MOVEI 5.
	SLEEP				; give it time to happen
	PTRD1S A			; slurp up what's left in the buffer
	 JRST DIEDIE
	JRST .-2
DIEDIE:	RESET ? EXIT

...LIT:	CONSTANTS

; Wonderful network routines

SVRRTS==-1				; include server routines
ERRTNS==-1				; include error routines
ERRHAN==-1				; include automagic error handling
ERRINS==<JRST SUICID>			; error instruction
HSTTAB==-1				; include host table magic
HSTSIX==-1				; and alias name kludge

.INSRT NETWRK[NET,MRC]

END TELSER