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6-1-monitor/enet.mac
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;SRC:<6.1.MONITOR.STANFORD>ENET.MAC.124, 26-Nov-86 13:19:56, Edit by BILLW
; Make IPRCI1-2 more lenient of mismatched hardware/software data lengths
;[SU-SIERRA.ARPA]FS1:<DEC.6.1.MERGE>ENET.MAC.123, 20-Jun-86 16:13:28, Edit by GROSSMAN
; ETHINI - ignore NCTs if NTLADR is invalid. This prevents the setting of
; a bogus PUP host address.
;<6-1-MONITOR>ENET.MAC.121, 5-May-85 14:27:44, Edit by LOUGHEED
; Type packet length on BADIP bugchk.
; Detect, report, and discard trailer encapsulated IP datagrams
;<6-1-MONITOR>ENET.MAC.120, 28-Apr-85 15:59:20, Edit by LOUGHEED
; Change PSKED reference to PSKD1 to minimize scheduler thrashing
;<6-1-MONITOR>ENET.MAC.119, 8-Apr-85 22:48:03, Edit by LOUGHEED
; SUBNTF flag controls use of subnets
;<6-1-MONITOR>ENET.MAC.118, 18-Mar-85 12:36:43, Edit by LOUGHEED
;<6-1-MONITOR>ENET.MAC.116, 15-Mar-85 14:54:31, Edit by LOUGHEED
;Move code into extended code section
;Flush previous edit history
SEARCH PROLOG,PHYPAR,ANAUNV
TTITLE (ENET,ENET,< - Ethernet Routines for PUP and IP Protocols>)
SUBTTL Kirk Lougheed / Stanford University / 26-February-83
; Copyright (c) 1983, 1984, 1985
; The Board of Trustees, Leland Stanford Junior University, Stanford, CA 94305
; All Rights Reserved.
; The information in this software is subject to change without notice
; and should not be construed as a commitment by Stanford University.
; Stanford assumes no responsibility for the use or reliability of
; this software.
SUBTTL Parameter Definitions
IFNDEF STANSW,<STANSW==0> ;Define Stanford site switch
IFNDEF PUPSW,<PUPSW==0> ;Define switch for PUP protocol support
IFNDEF REL6,<REL6==1> ;Default assembly for Release 6.x
IFE REL6,<DEFINE XSWAPCD <SWAPCD>>
IFE REL6,<DEFINE XRESCD <RESCD>>
EXTN <PKORCI,PKOWAI> ;Symbols defined in PKOPR.MAC
EXTN <ARPENQ,RESOLV> ;Symbols defined in ARP.MAC
IFN STANSW,<
COMMENT \
At Stanford we split our network into subnets and (at present) use
the PUP routing mechanisms to maintain knowledge of the SU-Net's topology.
The gateways do not speak ICMP, but do know how to forward datagrams for a
variety of protocols. We borrow from the Stanford PUP code to figure out how
to set up the Ethernet encapsulation.
\
;DEFSTR's from PUP.MAC describing an entry in the PUPROU routing table
DEFSTR ROUACC,PUPROU-1,0,1 ;Bit is set if network inaccessible
DEFSTR ROUBRD,PUPROU-1,1,1 ;Bit is set if broadcasts allowed
DEFSTR ROUNET,PUPROU-1,9,8 ;Net to which packets should be routed
DEFSTR ROUHST,PUPROU-1,17,8 ;Host to which packets should be routed
DEFSTR NETADR,PUPROU-1,35,18 ;Our address on this net (0 =) not on net)
IFE PUPSW,<
PRINTX ? Must have PUP code for SUNet routing at Stanford
PASS2
END
>
>;IFN STANSW
;Some useful local macros
;ETHHST - extract subnet host number from Internet address
DEFSTR ETHHST,,35,8 ;Ethernet subnet host number (all classes)
;SUBNET - extract an Ethernet subnet number from an Internet address.
;Both SRC and DST must be AC's.
DEFINE SUBNET(DST,SRC) <
TXNN SRC,.NETCA ;Class A network?
JRST [ LDB DST,[POINT 8,SRC,19]
JRST .+2] ;Yes, get the subnet number
LDB DST,[POINT 8,SRC,27] ;No, must be class B or C
>
;SETSUB - set an Ethernet subnet field in an Internet address.
;Both SRC and DST must be AC's.
DEFINE SETSUB(SRC,DST) <
TXNN DST,.NETCA ;Class A network?
JRST [ DPB SRC,[POINT 8,DST,19]
JRST .+2] ;Yes, get the subnet number
DPB SRC,[POINT 8,DST,27] ;No, must be class B or C
>
;Iorb parameters
NPIRB==^D20 ;Number of iorbs
PUIRBL==IRBLLN*NPIRB ;Length of iorb buffer
MINIRC==NPIRB/4 ;Reserve these many iorbs for interrupt level
IFL MINIRC-2,<MINIRC==4> ;Minimum is two iorbs/MEIS. Assume two MEIS's.
IRBTMO==^D5000 ;Wait five seconds to declare a MEIS hung
;Ethernet encapsulation - offsets from LCLPKT storage offset.
; Offset zero is a fake free storage header -- see MAXLDR definition.
OFF3MB==<PKTELI-1-LCLPKT> ;Offset of start of 3MB encapsulation
OFFETH==<PKTELI-4-LCLPKT> ;Offset of start of 10MB encapsulation
;Sanity check in case someone changes MAXLDR again
IFL MAXLDR-5 <PRINTX MAXLDR too small for 10MB Ethernet operation>
IFL MAXLDR-2 <PRINTX MAXLDR too small for 3MB Ethernet operation>
DEFSTR E3DST,OFF3MB+0,7,8 ;3MB Destination host
DEFSTR E3SRC,OFF3MB+0,15,8 ;3MB Source host
DEFSTR E3TYP,OFF3MB+0,31,16 ;3MB Type code
DEFSTR ETDH0,OFFETH+0,31,16 ;10MB First 16 bits of Destination host
DEFSTR ETDH1,OFFETH+1,31,32 ;10MB Last 32 bits of Destination host
DEFSTR ETSH0,OFFETH+2,31,32 ;10MB First 32 bits of Source host
DEFSTR ETSH1,OFFETH+3,15,16 ;10MB Last 16 bits of Source host
DEFSTR ETTYP,OFFETH+3,31,16 ;10MB Type code
;Ethernet packet types
ET%PUP==1000 ;PUP
ET%3IP==1001 ;IP on 3MB net
ET%IP==4000 ;IP on 10MB
ET%ARP==4006 ;RFC826 Address Resolution
ET%XRX==1001 ;Xerox PUP Address Resolution (cf. ET%3IP)
ET%TRL==10000 ;Trailer encapsulated IP
;Miscellaneous parameters
MINDAT==^D46 ;Minimum data portion for a 10MB datagram
;Resident Storage definitions
RS PUIRBF,PUIRBL ;IORB storage
RS IORBQ ;Free iorbs - linked through IRBSTS offset
RS IORBC ;Count of free iorbs
RS STAIMS ;No. process level iorb misses
RS STAIPR ;No. IP packets received
RS STAIBR ;No. IP bytes received
RS STAIRE ;No. IP reception errors
RS STAIPX ;No. IP packets transmitted
RS STAIBX ;No. IP bytes transmitted
RS STAIXE ;No. IP transmission errors
RS STAIRF ;No. malformed IP packets received
RS STAIBF ;No. packets dropped because no buffers
RS STAIRS ;No. short IP packets received
RS STAERC ;No. of misc. Ethernet packets processed
RS STAIBC ;No. IP broadcasts received
RS STATRL ;No. of trailer encapsulated IP's received
RSI MEIBUG,<0> ;-1 if MEIS software debugging in effect
RSI IPBRDF,<-1> ;-1 if receiving IP broadcasts, 0 if flushing
RSI SUBNTF,<-1> ;-1 if using subnets, 0 if otherwise
XSWAPCD ;Start out swappable
SUBTTL IORB Allocation and Construction
;ASGIRB - assign an iorb block
;Call from process level only
;We *may* block if a free iorb can't be found.
;If we unblock because iorbs become free or the timer goes off, we return
; failure if we are still unable to get an iorb. This prevents jobs from
; hanging should the PHYSIO routines get confused.
;Returns +1, no IORB and either pup fork or net went down
; +2, T1/ iorb pointer
XRESCD ;We go IOPIOFF while NOSKED
ASGIRB::TDZA T4,T4 ;Set flag meaning first time through
ASGIR0: SETO T4, ;Set flag for second time through
NOSKED ;Prevent races
IOPIOFF ;Disable the relevant interrupts
MOVE T1,IORBC ;Get free iorb count
CAILE T1,MINIRC ;Always leave a few for interrupt level rtns
CALL ASGIRI ;Go get an iorb, return pointer in T1
JRST ASGIR1 ;None found or supply low, must block
IOPION ;Re-enable interrupts
OKSKED ;Allow scheduling again
RETSKP ;Return to caller
ASGIR1: IOPION ;Enable interrupts
OKSKED ;Allow scheduling
JUMPN T4,R ;Punt if second time through
SKIPE IORBQ ;Uninitialized iorb queue?
IFSKP.
CALL IRBINI ;Yes, probably a PUP process running early
JRST ASGIRB ;Init queue and try again
ENDIF.
AOS STAIMS ;Count a process level iorb miss
SKIPN JOBNO ;Are we a job zero process?
RET ;Yes, possible PUP or Internet bkgnd. Punt.
SKIPN NSKED ;NOSKED?
SKIPE INSKED ;Or in scheduler?
RET ;Yes, can't block.
MOVE T1,TODCLK ;Get present time
ADDI T1,IRBTMO ;Make it a little bit in the future
HRLZ T1,T1 ;Set up for scheduler test
HRRI T1,IORBQT ;Wait for free iorb, timeout, or no Ethernet
HDISMS(^D200) ;Wait for condition to be true
SKIPN NETSUP ;Did network service go away?
RET ;Yes, leave this test
JRST ASGIR0 ;No, maybe we now have some buffers
XSWAPCD
;IORBQT - test for free iorbs
;Argument is timeout interval (right half of TODCLK)
;Callers are: ASGIRB
RESCD
IORBQT: SKIPN NETSUP ;Networks still up?
JRST 1(T4) ;No, wakeup so connection will be killed
MOVE T2,IORBC ;Get free iorb count
CAILE T2,MINIRC ;Sufficient count for process level activity?
JRST 1(T4) ;Yes, wakeup
HRRZ T2,TODCLK ;Get some of now
SUB T1,T2 ;Is timeout still in the future?
JUMPGE T1,0(T4) ;Yes, keep on sleeping
BUG.(CHK,IORBQX,ENET,SOFT,<ENET - no free iorbs>)
SETZM MEITIM ;Force a scan of the MEIS units
JRST 1(T4) ;Now wakeup
XSWAPCD
;ASGIRI - get a free iorb at interrupt level
;Call at interrupt level or NOSKED and IOPIOFF
;Returns +1 failure, no free iorbs
; +2 success, T1/ pointer to iorb block
;Clobbers T1-T4
XRESCD
ASGIRI::MOVEI T1,IORBQ ;Queue header
CALL LREMTQ ;Remove item at head of queue
IFNSK.
SETZM IORBC ;Nothing there, ensure consistent count
RET ;Single return to caller
ENDIF.
SOSGE IORBC ;Decrement iorb count
SETZM IORBC ;Fix it up if we have overly decremented it
MOVE T1,T2 ;Get pointer into place for caller
SETZM IRBSTS(T1) ;Clear out any status flags
RETSKP ;Return to caller
XSWAPCD
;RELIRB - Append an iorb to the free iorb queue
;Call at interrupt level only
;Takes T1/ pointer to iorb block
;Returns +1 always
;Clobbers T1-T3
XRESCD
RELIRB::AOS IORBC ;Increment free iorb count
MOVEI T2,IRBSTS(T1) ;T2/ link word
MOVEI T1,IORBQ ;T1/ queue header
CALLRET LAPPTQ ;append item to queue
XSWAPCD
;IRBINI - initialize queue of free iorbs
;Called from ETHINI before any MEIS is turned on.
;Returns +1 always
;Clobbers T1-T4
IRBINI: MOVEI T1,IORBQ ;Get address of queue header
HRLI T1,(T1) ;Form a nil queue pointer
MOVEM T1,IORBQ ;Make sure queue header is correct
SETZM IORBC ;No iorbs yet
MOVE T4,[XWD -NPIRB,PUIRBF] ;Form an aobjn-style pointer
IRBIN0: MOVEI T1,IORBQ ;T1/ Queue header
MOVEI T2,IRBSTS(T4) ;T2/ Link word is IRBSTS offset
CALL LAPPTQ ;Append this packet
AOS IORBC ;Count another iorb
ADD T4,[XWD 1,IRBLLN] ;Increment the pointer
JUMPL T4,IRBIN0 ;Loop over all packets
RET ;Return to caller
;LREMTQ - Remove item from head of queue (assumes local addresses)
;Takes T1/ Address of queue header
;Returns +1 Queue empty
; +2 T2/ Address of item removed
; T3/ Address of new head item
;Clobbers T2,T3
XRESCD
LREMTQ: HRRZ T2,(T1) ;Get current head
CAIN T2,(T1) ;Empty?
RET ;Yes, fail
HRRZ T3,(T2) ;No, get successor
HRRM T3,(T1) ;Queue head _ successor
HRLM T1,(T3) ;Successor's predecessor _ queue header
SETZM (T2) ;Clear links in removed item
RETSKP ;Skip return
XSWAPCD
;LAPPTQ - Append item to queue
; T1/ Address of queue header
; T2/ Address of item to append
;Returns +1:
; T3/ Address of previous tail item
;Clobbers T3
XRESCD
LAPPTQ: PUSH P,T4 ;Save callers T4
HRRZ T4,T1 ;In section pointer
HLRZ T3,(T4) ;Get current tail
HRLM T2,(T4) ;Queue tail _ new PB
HRRZ T4,T2 ;In section pointer
HRRZM T1,(T4) ;New PB's successor _ queue header
HRLM T3,(T4) ;New PB's predecessor _ old tail
HRRM T2,(T3) ;Old tail's successor _ new PB
POP P,T4
RET
XSWAPCD
;BLDCCW - Compute and set up CCW words for a datagram
;Takes T1/ pointer to iorb
; T2/ starting address of datagram (including Ethernet encapsulation)
; T3/ number of 36-bit words in datagram
; T4/ CDB,,UDB entry for MEIS
;Returns +1 always, CCW offsets set in IORB, T1/ pointer to iorb
;Clobbers T1-T4
XRESCD
BLDCCW::SAVEAC <Q1> ;We use Q1 as the iorb pointer
STKVAR <BLDOFF,BLDADR,BLD2ND> ;Declare local storage
MOVE Q1,T1 ;Set up iorb pointer
HLRZM T4,BLDOFF ;Save only the CDB address
MOVEM T2,BLDADR ;Set up starting address of datagram
ANDI T2,777 ;Want just address bits for start of datagram
ADD T2,T3 ;Calculate address of last word
SUBI T2,1 ; ...
TRNN T2,777000 ;Did we cross a page boundary?
JRST BLDCC0 ;No, calculate just one CCW
ANDI T2,777 ;Want just address bits again
ADDI T2,1 ;Correct count (word 0 is counts as 1)
MOVEM T2,BLD2ND ;Number of words spilled into other page
MOVE T1,T3 ;Get total word count
SUB T1,T2 ;Subtract number of words on other page
HRLI T1,IRMWRD ;T1/ Data mode,,word count
MOVE T2,BLDADR ;Get address of packet buffer
MAP T2,(T2) ;T2/ Physical address of datagram start
TLZ T2,777760 ;Mask off mapping information
MOVE T3,BLDOFF ;T3/ CDB address
CALL PHYCCW ;Calculate first CCW
MOVEM T1,IRBCC0(Q1) ;Stash it
MOVE T1,BLD2ND ;Get number of words on second page
HRLI T1,IRMWRD ;T1/ data mode,,word count
MOVE T2,BLDADR ;Start of packet buffer
XMOVEI T2,1000(T2) ;Increment page count
ANDCMI T2,777 ;Mask off address bits
MAP T2,(T2) ;T2/ physical address of second page
TLZ T2,777760 ;Mask off mapping information
MOVE T3,BLDOFF ;T3/ CDB address
CALL PHYCCW ;Calculate second CCW
MOVEM T1,IRBCC1(Q1) ;Stash it
SETZM IRBCC2(Q1) ;End list with a zero
MOVEI T1,IRBCC0(Q1) ;List header
HRLI T1,IRBCC2(Q1) ;List tail
JRST BLDCC1 ;Join common exit code
BLDCC0: MOVE T1,T3 ;Set up word count
HRLI T1,IRMWRD ;T1/ word data mode,,word count
MOVE T2,BLDADR ;Get address of packet buffer
MAP T2,(T2) ;Convert virtual address to physical address
TLZ T2,777760 ;T2/ mask out extraneous mapping information
MOVE T3,BLDOFF ;T3/ address of CDB
CALL PHYCCW ;Compute CCW data
MOVEM T1,IRBCC0(Q1) ;Stash it
SETZM IRBCC1(Q1) ;Only one CCW, terminate the list
MOVEI T1,IRBCC0(Q1) ;Head of transfer list
HRLI T1,IRBCC1(Q1) ;Tail of transfer list
BLDCC1: MOVEM T1,IRBXFL(Q1) ;set up transfer pointers
MOVE T1,Q1 ;Return iorb pointer in T1
RET ;Return to caller
XSWAPCD
;BLDIOR - build an iorb for reading an Ethernet datagram
;Takes T1/ byte count
; T2/ buffer pointer
; T3/ MEIS data mode
; T4/ done interrupt routine addresses: reception error,,reception okay
; P1/ NCT address
;Returns +1 failure, insufficient resources
; +2 success, T1/ pointer to IORB
XRESCD
BLDIOR::ASUBR <IORBYT,IORBUF,IORMOD,IORDUN> ;Declare local storage
CALL ASGIRI ;Get an iorb
IFNSK.
MOVE T1,IORBUF ;Get pointer to buffer
JRST RETBUF ;Flush buffer and return
ENDIF.
MOVE T4,T1 ;Put iorb pointer into T4
MOVE T2,IORBUF ;Get back buffer pointer
STOR T2,IRBUF,(T4) ;Remember buffer address
MOVX T2,IRFRED ;Function is read
STOR T2,ISFCN,(T4) ; ...
MOVEI T2,ETHRIN ;Address of done interrupt handling
MOVEM T2,IRBIVA(T4) ; ...
MOVE T2,IORDUN ;Addresses of buffer disposal routines
MOVEM T2,IRBDUN(T4) ; ...
SETZRO IRTRF,(T4) ;No trailer
SETONE IRHDR,(T4) ;32-bit headers
MOVE T1,IORBYT ;Set packet length
MOVEM T1,IRBCNT(T4) ; ...
MOVE T2,IORMOD ;Set data data mode
STOR T2,IRPMD,(T4) ; ...
MOVE T3,NTCAPC(P1) ;Get header count from NCT
STOR T3,IRHLN,(T4) ;Store it in the iorb, use as arg to WRDCNV
CALL WRDCNV ;Turn bytes into 36-bit words
MOVE T3,T1 ;T3/ Count of 36-bit words in datagram
MOVE T1,T4 ;T1/ Pointer to iorb
LOAD T2,IRBUF,(T1) ;T2/ Address of packet buffer
ADD T2,NTOFF(P1) ;Add offset to start of encapsulation data
MOVE T4,NTENCU(P1) ;T4/ Retrieve CDB,,UDB from NCT
CALL BLDCCW ;Set up channel control words
RETSKP ;Read this packet, T1/ iorb address
XSWAPCD
;BLDIOW - build an iorb for writing an Ethernet datagram
;Takes T1/ byte count
; T2/ buffer address
; T3/ MEIS data mode
; T4/ Address of done handling routine
; P1/ NCT pointer
;Returns +1 always, packet disposed off
BLDIOW::ASUBR <IOWBYT,IOWBUF,IOWMOD,IOWDUN> ;Declare local storage
CALL ASGIRB ;No, try for an iorb
IFNSK.
MOVE T1,IOWBUF ;No iorbs, get buffer address
JRST RETOUT ;Release buffer as if we sent it
ENDIF.
MOVE T4,T1 ;Use T4 to address iorb
MOVE T2,IOWBUF ;Get address of buffer
STOR T2,IRBUF,(T4) ;Store buffer pointer in iorb
SETZRO IRTRF,(T4) ;No trailer mode
MOVX T2,IRFWRT
STOR T2,ISFCN,(T4) ;Set function to writing
MOVEI T2,ETHWIN ;Done interrupt routine
MOVEM T2,IRBIVA(T4) ;Set done interrupt address
MOVE T1,IOWDUN ;Get address of buffer handling routine
MOVEM T1,IRBDUN(T4) ;Set it
SETONE IRHDR,(T4) ;Use 32-bit header mode
SKIPN NTETHR(P1) ;Skip if 10MB Ethernet
IFSKP.
MOVN T1,IOWBYT ;Get negative of data portion
ADDI T1,MINDAT ;Add smallest allowable data portion
SKIPLE T1 ;Skip if packet is larger than minimum
ADDM T1,IOWBYT ;Else pad the byte count for 10MB hardware
ENDIF.
MOVE T1,IOWBYT ;Get packet length in octets
ADDM T1,STAIBX ;Increment total byte count
AOS STAIPX ;Count another packet queued for output
MOVEM T1,IRBCNT(T4) ;Stash in iorb
MOVE T2,IOWMOD ;Get data mode
STOR T2,IRPMD,(T4) ;Stash in iorb
MOVE T3,NTCAPC(P1) ;Get header count from NCT
STOR T3,IRHLN,(T4) ;Stash in iorb, use as arg for WRDCNV
CALL WRDCNV ;Compute number of 36-bit words in packet
MOVE T3,T1 ;T3/ number of words in datagram
MOVE T2,IOWBUF ;Get back buffer pointer
ADD T2,NTOFF(P1) ;Add offset to start of encapsulation data
MOVE T1,T4 ;T1/ pointer to iorb
MOVE T4,NTENCU(P1) ;T4/ Get CDB,,UDB for this NI from NCT
CALL BLDCCW ;Assemble CCW words for the packet
MOVE T2,NTENCU(P1) ;Set up CDB,,UDB for call to physio routines
NOSKED ;Turn off scheduler
CALL PHYSIO ;Queue up packet for output
OKSKED ;Resume scheduling
RET ;Return to caller
;ETHRIN - Ethernet input done routine
;We are invoked by PHYSIO/PHYMEI on a done interrupt for a read
;Buffer release routines must expect buffer pointer in T1
;Takes T1/ pointer to iorb
;Returns +1 always
XRESCD
IFE REL6,<ETHRIN: EA.ENT>
IFN REL6,<XRENT ETHRIN>
PUSH P,T1 ;Save pointer to iorb
MOVE T4,T1 ;Copy iorb pointer
LOAD T1,IRBUF,(T4) ;Get buffer address
LOAD T2,IRDUN,(T4) ;Get done routine address
MOVE T3,IRBSTS(T4) ;Get status bits
TXNN T3,IS.ERR ;Everything okay?
IFSKP.
AOS STAIRE ;No, count number of reception errors
LOAD T2,IRBAD,(T4) ;Get address of buffer release routine
ENDIF.
CALL 0(T2) ;Take care of buffer
POP P,T1 ;Restore iorb pointer
CALLRET RELIRB ;Release iorb and return to caller
XSWAPCD
;ETHWIN - Ethernet output done routine
;We are invoked by PHYSIO/PHYMEI on a done interrupt from the MEIS
;Buffer release routines must expect buffer pointer in T1
;Takes T1/ pointer to iorb
;Returns +1 always
;Clobbers T1-T4
XRESCD
IFE REL6,<ETHWIN: EA.ENT>
IFN REL6,<XRENT ETHWIN>
PUSH P,T1 ;Save pointer to iorb
MOVE T2,IRBSTS(T1) ;Get iorb status flags
TXNE T2,IS.ERR ;Any error during the transfer?
AOS STAIXE ;Yes, just count it
LOAD T2,IRDUN,(T1) ;Get address of buffer disposal routine
LOAD T1,IRBUF,(T1) ;Get address of buffer
CALL 0(T2) ;Get rid of the buffer
POP P,T1 ;Retore iorb pointer
CALLRET RELIRB ;Put iorb back on free queue and exit
XSWAPCD
SUBTTL IP/Multinet Interface
;ETHINI (NTINI) - Network Initialization
;Set up the NCT for each MEIS on the system.
;Takes P1/ pointer to NCT
;Returns +1 always
;Clobbers T1-T4
ETHINI::SKIPG NTLADR(P1) ;NCT address initialized?
RET ;No, leave it alone
SKIPN IORBQ ;If iorb queue not yet set up
CALL IRBINI ;Then initialize pool of free iorbs
MOVE T1,DBUGSW ;Get setting of debug switch
CAIN T1,2 ;Standalone system?
SETOM MEIBUG ;Yes, turn on all bug reporting
MOVE T3,ENIUTP ;Get aobjn pointer for MEIS table
ETHIN0: SKIPN ENCUTB(T3) ;Do we have a MEIS here?
JRST ETHIN1 ;No, try next table entry
HRRZ T1,ENCUTB(T3) ;T1/ pointer to UDB
SKIPE MEUNCT(T1) ;Initialized yet wrt Internet?
ETHIN1: AOBJN T3,ETHIN0 ;Loop over all NI's
JUMPGE T3,R ;Just quit if no MEIS for this NCT
MOVE T1,ENCUTB(T3) ;Get CDB,,UDB of that MEIS
CALL MEITYP ;What type of MEIS?
SKIPA T4,[NT.3MB] ;3MB experimental Ethernet
MOVX T4,NT.ETH ;10MB standard Ethernet
LOAD T2,NTTYP,(P1) ;Get network type from NCT
CAIE T4,(T2) ;NCT matches hardware?
JRST ETHIN1 ;No, keep on looking.
MOVE T2,ENCUTB(T3) ;Get UDB,,CDB address pair
MOVEM T2,NTENCU(P1) ;Remember in NCT
HRRZS T2 ;Isolate UDB pointer
MOVEM P1,MEUNCT(T2) ;Save pointer to NCT in UDB
MOVE T3,NTLADR(P1) ;Get our Internet address
SUBNET T2,T3 ;Get our Ethernet subnet number
TXNE T3,.NETCA ;Test for a Class A address
TXNN T3,.NETCB ;Test for a Class B address
TRNA ;Class A or B, subnets are possible
SETO T2, ;Can't have subnets for Class C addresses
SKIPN SUBNTF ;Allowing the use of subnets?
SETO T2, ;No, say not possible
MOVEM T2,NTSUBN(P1) ;Stash subnet number or -1 in the NCT
IFN PUPSW,<
CAILE T2,NPNETS ;Within range?
IFSKP.
HRRZ T1,PUPPAR+2 ;Yes, get default PUP subnet number
SKIPN T1 ;Skip if already set
HRRM T2,PUPPAR+2 ;Else set the default now
ENDIF.
>;IFN PUPSW
LOAD T2,ETHHST,NTLADR(P1) ;Get our subnet (3MB Ethernet) host number
MOVEM T2,NTHSTN(P1) ;Stash it in the NCT
CAIE T4,NT.ETH ;Is this 10MB?
IFSKP.
SETOM NTETHR(P1) ;Set to -1 for testing convenience
MOVEI T2,^D8 ;Need 8 16-bit words for 10MB encapsulation
MOVEI T3,OFFETH ;Offset from LCLPKT (start of encaps.)
ELSE.
SETZM NTETHR(P1) ;Set to 0 for testing convenience
MOVEI T2,^D2 ;Need only 2 such words for the 3MB net
MOVEI T3,OFF3MB ;Offset from LCLPKT (start of encaps.)
ENDIF.
MOVEM T2,NTCAPC(P1) ;Stash in NCT
MOVEM T3,NTOFF(P1) ; ...
LSH T2,1 ;Compute number of encapsulation bytes
MOVEM T2,NTCAPB(P1) ;Remember that number as well
ADDI T2,4 ;Four bytes into IP is minimum for sniffing
MOVEM T2,NTIPMN(P1) ; ...
ADDI T2,^D20+^D20+^D8-4 ;IP header + TCP header + data is max for sniff
MOVEM T2,NTIPMX(P1) ; ...
RET ;All done, return to caller
;ETHON (NTRSRT) - Network restart instruction
;Set address mask and enable reception
;Takes P1/ pointer to NCT
;Returns +1 always
;Clobbers T1-T4
ETHON:: SKIPN T1,NTENCU(P1) ;Load CDB,,UDB for this interface
JRST ETHONX ;We never found the MEIS for this NCT
CALL MEISDN ;Is the MEIS already enabled?
IFNSK.
SKIPE NTORDY(P1) ;Yes, is output on?
RET ;Yes, to both, just quit
JRST ETHON1 ;MEIS on, output off. Go restart things.
ENDIF.
MOVE T1,NTENCU(P1) ;T1/ CDB,,UDB of MEIS unit
SKIPN NTETHR(P1) ;10MB Ethernet?
IFSKP.
MOVEI T2,1 ;Yes, use FSM 1 as our primary address slot
LOAD T3,HRDW0,(P1) ;Get first 32 bits of hardware address
LOAD T4,HRDW1,(P1) ;Get last 16 bits of hardware address
ELSE.
MOVE T2,NTHSTN(P1) ;Fetch our 3MB Ethernet host number
SETZB T3,T4 ;Clear these AC's, just in case
ENDIF.
CALL MEIADR ;Set address mask for this host
MOVE T1,NTENCU(P1) ;T1/ UDB,,CDB
CALL MEION ;Enable reception
IFN PUPSW,<
SKIPGE T1,NTSUBN(P1) ;Pick out our Ethernet subnet number
JRST ETHON1 ;Strange. PUP, but no subnets.
MOVE T2,NTHSTN(P1) ;Pick out our PUP (3MB) host number
TXO T2,1B1 ;Broadcasts allowed on local subnet
MOVEM T2,PUPROU-1(T1) ;Set PUP routing entry for this host
>;IFN PUPSW
ETHON1: SETOM NTSTCH(P1) ;Set change of state flag
SETOM NTORDY(P1) ;Ouput is possible
SETOM NTRDY(P1) ;Net is ready
RET ;Return to caller
;Here for a non-existent MEIS
ETHONX: SKIPE NETON(P1) ;Is the net alleged to be on?
RET ;No, it is off and that is good
SETOM NTSTCH(P1) ;Signal change of state
SETZM NETON(P1) ;Net is off
SETZM NTORDY(P1) ;Output is not possible
RET ;Return to caller
;ETHOFF (NTKILL) - Shutdown the interface
;This routine is a no-op if the MEIS is doesn't exist, is already off,
; or if someone has issued a SHUTDOWN command from the console.
;Returns +1 always
;Clobbers T1-T4
ETHOFF::MOVE T1,SCTLW ;Get scheduler control word
TXNN T1,1B3 ;Doing a SHUTDOWN? (We might be continued!)
SKIPN T1,NTENCU(P1) ;Load UDB,,CDB for this NI
RET ;Shutdown, or was never on. Do nothing.
CALL MEISDN ;Is the MEIS already down?
SKIPN T1,NTENCU(P1) ;No, load up UDB,,CDB again
RET ;Already off, do nothing
SETOM NTSTCH(P1) ;Set change of state flag
SETZM NETON(P1) ;State of network is off
SETZM NTRDY(P1) ;State of interface is off
SETZM NTORDY(P1) ;Output is not possible, don't queue packets
CALL MEIOFF ;Disable reception
RET ;Return to caller
Subttl Ethernet Reception Routines
;ETHRCI - Receive an Ethernet Datagram
;Called at interrupt level from PHYMEI
;Takes T1/ length of Ethernet packet in octets
; T2/ Ethernet packet type
; P3/ UDB of interrupting MEIS
;Returns +1 flush packet
RS RCILEN,1 ;Length seen by hardware
RS RCITYP,1 ;Type seen by hardware
;P1/ points to NCT
;P4/ points to buffer
XRESCD
IFE REL6,<ETHRCI::EA.ENT> ;Run in non-zero section (PHYSIO still in zero)
IFN REL6,<XRENT ETHRCI,G>
SKIPN INTON ;IP layer must be initialized
RET ;Punt if not
DMOVEM T1,RCILEN ;Save hardware length and type
SAVEP ;Preserve these AC'S
MOVE P1,MEUNCT(P3) ;Set up pointer to NCT
XMOVEI T3,PKORCI ;Default datagram handling routine
IFN PUPSW,<
CAIN T2,ET%PUP ;PUP? (Same code on both types of net)
XMOVEI T3,PUPRCI ;Yes.
>;IFN PUPSW
CAIN T2,ET%TRL ;IP trailer encapsulated?
XMOVEI T3,TRLRCI ;Yes.
SKIPN NTETHR(P1) ;Branch on type of interface
IFSKP.
CAIN T2,ET%IP ;10MB interface. Is it 10MB IP?
XMOVEI T3,IPRCI ;Yes.
CAIE T2,ET%XRX ;Xerox style ARP?
CAIN T2,ET%ARP ;RFC826 style ARP?
XMOVEI T3,ARPRCI ;Yes.
ELSE.
CAIN T2,ET%3IP ;3MB interface. Is it 3MB IP?
XMOVEI T3,IPRCI ;Yes.
ENDIF.
ETHRC0: CALL (T3) ;Dispatch to appropriate handler
RET ;Flush datagram sitting in RAM
RETSKP ;Start transfer, T1/ iorb pointer
XSWAPCD
;TRLRCI - Trailer encapsulated IP reception interrupt
;Called at interrupt level, assumes environment set up by ETHRCI
; Some paranoia code in case a UNIX system tries to use IP trailers
; to talk to us. We absolutely can't cope with this type of IP datagram.
;Returns +1 always, flush the datagram
XRESCD
TRLRCI: AOS STATRL ;Count number of these datagrams
SKIPE MEIBUG ;Skip if not debugging
BUG.(INF,IPTRLR,ENET,SOFT,<ENET - Received trailer encapsulated IP>)
RET ;Return to caller, flush datagram
XSWAPCD
;IPRCI - IP Reception Interrupt
;Called at interrupt level, assumes environment set up by ETHRCI
;Returns +1 flush packet
; +2 receive packet, T1/ pointer to iorb
XRESCD
IPRCI: CALL GETBFF ;Get a buffer for the packet
RET ;Can't, must flush it
MOVE P4,T1 ;Save pointer to packet
MOVE T4,RCILEN ;Get number of bytes in packet
CAML T4,NTIPMN(P1) ;If smaller than IP mininum
CAMLE T4,NTIPMX(P1) ;Or greater than the "small" IP cutoff
MOVE T4,NTIPMN(P1) ;Then "sniff" the minimum number of bytes
MOVE T1,NTOFF(P1) ;Get encapsulation offset from NCT
ADD T1,P4 ;Set up start address of packet
MOVE T2,NTENCU(P1) ;Set up CDB,,UDB of MEIS unit
CALL MEIRHD ;"Sniff" some bytes from packet into buffer
CALL CHKBRD ;Check for broadcast packet
JRST IPRBRD ;It is. Go think about it.
IPRCI0: LOAD T2,PIPL,-LCLPKT(P4) ;Get datagram length
CAIL T2,MINIHS ;Range check the length
CAMLE T2,INTXPB ; ...
JRST IPRCX0 ;Go flush the packet -- bad length
SKIPE NTETHR(P1) ;If 10MB interface and the software length...
CAIL T2,MINDAT ;...is less than the minimum hardware length
TRNA ;Neither, sanity test is valid
JRST IPRCI1 ;Then skip the usual sanity test
MOVE T1,RCILEN ;Get back length of packet seen by hardware
SUB T1,NTCAPB(P1) ;Compute hardware length less encapsulation
SUBI T1,(T2) ;Compare software and hardware counts
IFE STANSW,<
CAILE T1,1 ;Should differ at most by one byte (3MB only)
>;IFE STANSW
IFN STANSW,<;;; Some machines (eg symbolics 3600) send out "bogus" packets
CAILE T1,20 ;do SOME sanity checking
>;IFN STANSW
JRST IPRCX0 ;Bad packet, flush it
IPRCI1: ADDM T2,STAIBR ;Increment count of bytes received
AOS STAIPR ;Increment count of packets received
MOVE T1,RCILEN ;Get back total packet size
CAMLE T1,NTIPMX(P1) ;Small packet? (optimize channel activity)
IFSKP.
AOS STAIRS ;Count another small IP received
MOVE T1,P4 ;Get back buffer address
JRST APPIP ;Append to IP input queue and flush packet
ENDIF.
MOVE T1,T2 ;T1/ Must read over Massbus. Get byte count.
MOVE T2,P4 ;T2/ Buffer address
MOVX T3,.PM32 ;T3/ 32-bit data mode
MOVE T4,[XWD RETBUF, APPIP] ;T4/ Buffer handling routines
CALL BLDIOR ;Construct iorb for reading
RET ;Some failure, flush packet
RETSKP ;Success, pass iorb back to physio
;Here when an IP packet with a bogus length is detected
;Should figure out a way of reporting the sender, net, etc.
IPRCX0: AOS STAIRF ;Count a bad packet
SKIPE MEIBUG ;MEIS debugging?
IFE STANSW,<
BUG.(CHK,BADIP,ENET,HARD,<ENET - Bad IP packet>) ;Yes, complain
>;IFE STANSW
IFN STANSW,<
BUG.(CHK,BADIP,ENET,HARD,<ENET - Bad IP packet>,<<T2,LENGTH>>) ;Yes, complain
>;IFN STANSW
MOVE T1,P4 ;Get pointer to buffer
CALL RETBUF ;Release it
RET ;Return and flush the packet
;IPRBRD - here to handle an IP broadcast. We have special code here since
; we occasionally want to disable IP broadcast reception when some other
; host has a brain damaged implementation that is flooding us with datagrams.
IPRBRD: AOS STAIBR ;Count a broadcast received
SKIPE IPBRDF ;Flushing IP broadcasts?
JRST IPRCI0 ;No, go read it in using normal code
MOVE T1,P4 ;Yes, get pointer in place
CALL RETBUF ;Release storage
CALL PKOWAI ;Is the waif listener interested?
RET ;No, flush the datagram
RETSKP ;Yes, T1/ iorb pointer
XSWAPCD
;APPIP - append an IP packet to the IP input queue
;Call at interrupt level
;Takes T1/ pointer to buffer
;Clobbers T1-T2
XRESCD
APPIP: PIOFF ;Make sure PI system is off (lock out AN20)
MOVE T2,INTIBI ;Get input queue tail pointer
JUMPN T2,APPIP0 ;Queue not empty, go append packet
MOVEM T1,INTIBO ;Was empty. This is only item now.
SKIPA ;Make head and tail be same packet
APPIP0: STOR T1,NBQUE,(T2) ;Make old packet point to newest packet
MOVEM T1,INTIBI ;Set new tail pointer
AOS INTFLG ;Cause Internet process to notice it
IFN STANSW,< ;NULJBF is Release 6 and Stanford Release 5.3+
IFE REL6,<
SKIPE NULJBF ;Is scheduler running the null job?
AOS PSKED ;Yes, wake it up
>;IFE REL6
>;IFN STANSW
IFN REL6,<AOS PSKD1 ;Minimize scheduler latency>
PION ;Turn PI system back on
RET ;Return to caller
XSWAPCD
;CHKBRD - check if datagram is a broadcast
;Call at interrupt or process level
;Takes P1/ NCT pointer
; P4/ buffer pointer
;Returns +1 broadcast packet
; +2 not broadcast (may be multicast, though)
;Clobbers T1-T4
XRESCD
CHKBRD: SKIPN NTETHR(P1) ;10MB Ethernet?
IFSKP.
LOAD T1,ETDH0,(P4) ;Yes, get first 16-bits of destination
TRC T1,177777 ;Complement those bits
JUMPN T1,RSKP ;If some still set, can't be broadcast
LOAD T1,ETDH1,(P4) ;Get last 32-bits of destination
TLO T1,740000 ;Set low four bits
CAME T1,[-1] ;Skip if all bits now set (broadcast)
RETSKP ;Not broadcast, skip return
ELSE.
LOAD T1,E3DST,(P4) ;Get 3MB destination
JUMPN T1,RSKP ;Zero is broadcast on 3MB net
ENDIF.
RET ;And take a single return
XSWAPCD
;ARPRCI - process an ARP packet
;Called at interrupt level, assumes environment set up by ETHRCI
;For now we "sniff" the entire packet into the buffer and append the buffer
; to the ARP input queue. The assumption is that ARP datagrams are very
; small, making it inefficient to fire up the channel for a transfer.
;Takes P1/ NCT pointer
;Returns +1 flush packet
; +2 read packet, T1/ iorb pointer
XRESCD
ARPRCI: SUB T1,NTCAPB(P1) ;Discount encapsulation bytes
CAIL T1,^D12 ;Smallest ARP assuming 8-bit hard/prot address
CAMLE T1,INTXPB ;Fits within an IP buffer?
RET ;Bad packet size, return to caller
CALL GETBFF ;Get an Internet buffer
RET ;No buffers, must flush packet
MOVE P4,T1 ;Stash buffer pointer in P4
ADD T1,NTOFF(P1) ;Add encapsulation offset into buffer
MOVE T2,NTENCU(P1) ;Get CDB,,UDB of MEIS unit
MOVE T4,RCILEN ;Get byte count
CALL MEIRHD ;Read entire (short) packet into buffer
MOVE T1,P4 ;Get back buffer pointer
MOVE T2,P1 ;NCT pointer is argument as well
CALL ARPENQ ;Hang buffer on ARP input queue
RET ;Flush the packet
XSWAPCD
;GETBFF - claim and check a free Internet buffer
;Call at interrupt level
;The pointer returned by GETBFF points at the PKTELI offset, the beginning of
; the data. LCLPKT is the preceding offset that marks the beginning of the
; four words of encapsulation data.
;Returns +1 no free buffers, Internet fork prodded
; +2 good buffer claimed, T1/ pointer to buffer
;Clobbers T1-T4
XRESCD
GETBFF::PIOFF ;Lock out rest of machine
SOSGE INTNFI ;Any buffers?
AOSA INTNFI ;No, fix count
TRNA ;Yes, skip into main code
JRST GETBFX ;Go poke Internet fork
MOVE T1,INTFRI ;Get first buffer on queue
TRNN T1,-1 ;Null queue is a bug
BUG.(HLT,ENTBUF,ENET,SOFT,<ENET - free buffer queue fouled>)
LOAD T2,NBQUE,(T1) ;Get pointer to next buffer
SKIPE T2 ;If non-zero
SETSEC T2,INTSEC ;Then make an extended address
MOVEM T2,INTFRI ;Update head of free queue
PION ;Let rest of machine run again
SETZRO NBQUE,(T1) ;Clear pointer to next buffer
CAML T1,[XWD INTSEC,INTFRE] ;Range check the pointer
CAMLE T1,[XWD INTSEC,INTFRE+INTFSZ-1] ; ...
BUG.(HLT,ENTBF1,ENET,SOFT,<ENET - bad Internet buffer>)
RETSKP ;Good return to caller
GETBFX: PION ;Turn PI system back on
AOS INTFLG ;Signal work to do
AOS STAIBF ;Increment count of buffer misses
SKIPE MEIBUG ;Debugging?
BUG.(INF,ETHBFX,ENET,SOFT,<ENET - no free IP buffers>) ;Yes, complain
RET ;Return to caller
XSWAPCD
;RETBUF - release an Internet buffer to the Internet free pool
;Call at interrupt level
;Takes T1/ buffer pointer
;Returns +1 always
;Clobbers T1-T2
XRESCD
RETBUF::CAML T1,[XWD INTSEC,INTFRE] ;Range check the pointer
CAMLE T1,[XWD INTSEC,INTFRE+INTFSZ-1] ; ...
IFNSK.
BUG.(CHK,RETBFZ,ENET,SOFT,<ENET - bad buffer pointer at RETBUF>)
RET ;Don't foul free queue if bad pointer
ENDIF.
OPSTR <SKIPN>,PFSIZ,-LCLPKT(T1) ;Full size packet?
BUG.(CHK,RETBFX,ENET,SOFT,<ENET - Bad packet size>)
MOVE T2,T1 ;Copy for indexing below
PIOFF ;Maintain queue integrity (lock out AN20)
EXCH T1,INTFRI ;Release to Internet
STOR T1,NBQUE,(T2) ; ...
AOS INTNFI ;Count another free buffer
PION ;Let rest of machine run
RET ;Return to caller
XSWAPCD
Subttl IP Output Routines
;ETHOOK (NTOTOK) - net output okay
;Called T1/ (first hop) destination address
; T2/ pointing to an Internet buffer
; P1/ address of NCT
;Returns +1 no can do, T1/ ICMP error code
; +2 success, Ethernet encapsulation done
;Clobbers T1,T3,T4, does NOT clobber T2
;Note that we do the Ethernet encapsulation at this point rather than in
; the ETHHDR (NTLLDR) routine. We have all the information here and it
; makes little sense to substantially repeat this work later.
ETHOOK::SAVEAC<T2> ;Preserve this AC
STKVAR<DEST> ;Declare local storage
MOVEM T1,DEST ;Store destination address
MOVX T3,ET%IP ;Get type code for 10MB IP
SKIPN NTETHR(P1) ;Skip if 10MB Ethernet
MOVX T3,ET%3IP ;Get type code for 3MB IP
CALL ENCAPS ;Encapsulate the datagram
JRST ETHOKX ;Can't send packet, generate ICMP error
RETSKP ;Good return to caller
;Here when we can't do anything
ETHOKX: SKIPE JOBNO ;Never complain if job zero (ping code)
SKIPN MEIBUG ;Do complain if MEIS debugging
TRNA ;No complaints if not debugging or job zero
BUG.(INF,ETHRTX,ENET,SOFT,<ENET - IP routing failure>) ;complain
JUMPE T1,ETHOK1 ;Jump if temporary failure because of ARP
MOVE T1,DEST ;Get back destination
CALL HSTDWN ;Signal that host is inaccessible
ETHOK1: MOVX T1,<ICM%SQ> ;ICMP error is "source quench"
RET ;Take failure return
ENDSV.
;HSTDWN - signal upper levels that a host is not accessible
;Should define another status bit meaning "Gateway is down, host inaccessible"
;Takes T1/ internet address
;Returns +1 always
HSTDWN: JUMPE T1,R ;Quit now if no specific host
CALL HSTHSH ;Find hash index for host
RET ;No index, just return
MOVX T1,HS%VAL ;Get valid flag
IORM T1,HSTSTS(T2) ;Set it
MOVX T1,HS%UP ;Get host up flag
ANDCAM T1,HSTSTS(T2) ;Be sure to clear it
RET ;Return to caller
;ETHOUT (NTOSRT) - Start output on the MEIS
;Examine queued Internet packets and send one if possible
;Takes P1/ pointer to NCT
;Returns +1 always
ETHOUT::SKIPE NTIOBO(P1) ;Anything at head of Internet output queue?
CALL GETOUT ;Yes, pull it off the queue
RET ;Nothing there or lost timing race
MOVE T2,T1 ;T2/ Get buffer pointer into place
LOAD T1,PIPL,-LCLPKT(T2) ;T1/ Get packet length in octets
MOVX T3,.PM32 ;T3/ 32-bit data mode
MOVEI T4,RETOUT ;T4/ Buffer disposal routine
CALL BLDIOW ;Construct and queue up an Ethernet write
NOP ;Ignore any errors
RET ;Single return always
;GETOUT - pull a packet off the Internet output queue
;Takes P1/ pointer to NCT
;Returns +1 no packets to be sent
; +2 success, T1/ address of packet to send
;Clobbers T1-T2
XRESCD
GETOUT: PIOFF ;Interlock with PI system
SKIPN T1,NTIOBO(P1) ;Load pointer to head of Internet queue
JRST GETOU1 ;Nothing to do, quit
LOAD T2,NBQUE,(T1) ;Get successor packet
SKIPE T2 ;Don't extend if nil
SETSEC T2,INTSEC ;Make extended address
MOVEM T2,NTIOBO(P1) ;Update queue header
SKIPN T2 ;Now a null queue?
SETZM NTIOBI(P1) ;Yes, clear tail pointer as well
SETZRO NBQUE,(T1) ;Clear links in dequeued packet
AOS (P) ;Prepare skip return
GETOU1: PION ;Reallow PI now that queues are safe
RET ;Good return to caller
XSWAPCD
;RETOUT - Release an IP output buffer
;Called from interrupt level
;This routine makes no assumptions about the size of the buffer and thus
; hooks it to the general free list that the background fork looks at.
;Takes T1/ buffer pointer
;Returns +1 always
;Clobbers T1-T2
XRESCD
RETOUT: CAML T1,[XWD INTSEC,INTFRE] ;Range check the pointer
CAMLE T1,[XWD INTSEC,INTFRE+INTFSZ-1] ; ...
IFNSK.
BUG.(CHK,RETOTX,ENET,SOFT,<ENET - bad buffer pointer at RETOUT>)
RET ;Don't foul free queue if bad pointer
ENDIF.
MOVE T2,T1 ;Copy buffer pointer for indexing
PIOFF ;Make sure no one can manipulate free list
EXCH T1,INTNFB ;Put on free list
STOR T1,NBQUE,(T2) ;Hang old list off of this new head
PION ;Reallow PI activity
AOS INTFLG ;Get Internet gateway to notice it
RET ;Return to caller
XSWAPCD
SUBTTL Subnet Routing and Ethernet Encapsulation
;ENCAPS - perform IP and PUP encapsulation
;Takes T1/ address - if IP, right justified 32-bits of first hop address
; if PUP, 1B0+subnet,,host of ultimate destination
; T2/ buffer pointer with zero point at start of 10MB encapsulation field
; T3/ protocol type code
; P1/ NCT address
;Returns +1 failure, T1/ -1 if no path, 0 if ARP needed
; +2 success, network dependent datagram encapsulation performed
;Clobbers T1-T4
;Q1 - scratch AC for SUBROU
;Q2 - buffer pointer
;Q3 - type code
ENCAPS::SAVEQ ;We use these AC's
DMOVEM T2,Q2 ;Load up buffer pointer, datagram type
XMOVEI T4,ENCETH ;Assume we want standard 10MB encapsulation
SKIPN NTETHR(P1) ;Standard 10MB Ethernet?
XMOVEI T4,ENC3MB ;No, we want 3MB encapsulation
CALL 0(T4) ;Do the output okay, encapsulation checks
RET ;Failure
RETSKP ;Success return to caller
;ENC3MB - perform 3MB datagram encapsulation
;Set source and destination host addresses
;Takes T1/ PUP or IP address
; Q2/ buffer pointer
; Q3/ protocol type
; P1/ NCT address
;Returns +1 routing failure, T1/ -1 if hard error, 0 if temporary (ARP)
; +2 success, encapsulation data set up
;Clobbers T1,T3-T4, Preserves T2
ENC3MB: CAIE Q3,ET%3IP ;Is the protocol 3MB IP?
JRST ENC3M0 ;No, go straight to subnet routing
LOAD T3,ETHHST,T1 ;Get IP destination
CAIE T3,377 ;Host 377 is IP broadcast address
JRST ENC3M0 ;Standard IP, do subnet routing
MOVE T3,NTHSTN(P1) ;Get source host number from NCT
SETZ T4, ;Destination address is broadcast
JRST ENC3M1 ;Set up broadcast addresses
ENC3M0: CALL SUBROU ;Do subnet routing
JRST RETO ;Not possible, return hard failure
ENC3M1: STOR T3,E3SRC,(Q2) ;Set source host number
STOR T4,E3DST,(Q2) ;Set destination host number
STOR Q3,E3TYP,(Q2) ;Set packet type
RETSKP ;Skip return to caller
;ENCETH - perform 10MB datagram encapsulation
;Set source and destination host addresses
;Takes T1/ PUP or IP address
; Q2/ buffer pointer
; Q3/ protocol type
; P1/ NCT address
;Returns +1 routing failure, T1/ -1 if hard error, 0 if temporary (ARP)
; +2 success, encapsulation data set up
;Clobbers T1,T3-T4, Preserves T2
ENCETH: CAIE Q3,ET%PUP ;PUP packet?
IFSKP.
TRNN T1,-1 ;Host 0 is PUP broadcast address
JRST ENCET1 ;Doing a broadcast
ELSE.
LOAD T2,ETHHST,T1 ;Get IP destination
CAIN T2,377 ;Host 377 is IP broadcast address
JRST ENCET1 ;Doing a broadcast
ENDIF.
SKIPGE NTSUBN(P1) ;Do we have subnets?
JRST ENCET2 ;No, skip the subnet routing stuff
CALL SUBROU ;Do subnet routing
JRST RETO ;Not possible. Return hard failure.
MOVE T3,NTSUBN(P1) ;Get our subnet number ready
CAIE Q3,ET%PUP ;PUP packet?
IFSKP.
HRRZ T1,T4 ;Resolve just the first hop host number
HRLI T1,(T3) ;Form subnet,,host
ELSE.
STOR T4,ETHHST,T1 ;Set first hop host number
SETSUB T3,T1 ;Set first hop subnet number
ENDIF.
ENCET2: MOVE T2,Q3 ;T2/ protocol type
CALL RESOLV ;Turn protocol address into hardware address
JRST RETZ ;Can't do it, return soft error
STOR T1,ETDH0,(Q2) ;First 16 bits of destination host
STOR T2,ETDH1,(Q2) ;Last 32 bits of destination
ENCET0: LOAD T1,HRDW0,(P1) ;Get first 32 bits of our hardware address
STOR T1,ETSH0,(Q2) ;Set in datagram
LOAD T1,HRDW1,(P1) ;Get last 16 bits of our hardware address
STOR T1,ETSH1,(Q2) ;Set in datagram
STOR Q3,ETTYP,(Q2) ;Set type field
RETSKP ;Skip return
;Here to set hardware broadcast destination address
ENCET1: SETONE ETDH0,(Q2) ;-1 is broadcast address
SETONE ETDH1,(Q2) ; ...
JRST ENCET0 ;Join rest of encapsulation code
;SUBROU - do subnet routing
;Takes T1/ network address: PUP: 1B0+subnet,,host
; IP: 32 bits right justified
; Q2/ buffer pointer
;Returns +1 destination inaccessible
; +2 success, T3/ source host (8 bits)
; T4/ destination host (8 bits)
;Clobbers Q1, T2-T4
;At Stanford we must consult the PUP routing table to figure out if we need
; to use a local gateway to get to the destination host. Other sites that
; want to use subnet routing need to implement some other scheme.
IFE STANSW,<
SUBROU: BUG.(INF,SUBRTX,ENET,SOFT,<ENET - Subnet routing scheme not defined>)
RET ;Complain and return
>;IFE STANSW
IFN STANSW,<
SUBROU: IFL. T1 ;If trying to route PUP
LDB Q1,[POINT 8,T1,17] ;Get subnet from left half
ELSE.
SUBNET Q1,T1 ;Otherwise get destination subnet from IP addr.
ENDIF.
CAILE Q1,NPNETS ;Within range of routing table?
RET ;No, call it inaccessible
SKIPE Q1 ;Allow subnet zero to mean connected subnet
CAMN Q1,NTSUBN(P1) ;On our subnet?
IFNSK.
MOVE T3,NTHSTN(P1) ;Yes, get our subnet host number
CALL USEDST ;Default host according to PUP or IP argument
RETSKP ;Take good return
ENDIF.
JN ROUACC,(Q1),R ;Punt if subnet is inaccessible
LOAD T4,ROUHST,(Q1) ;Get host we route to on dest subnet
SKIPN T2,T4 ;Zero means route directly
CALL USEDST ;So use destination we were given
SKIPE T2 ;Were we routing?
LOAD Q1,ROUNET,(Q1) ;Yes, get subnet we are routing to
LOAD T3,NETADR,(Q1) ;Get our address on that subnet
JUMPE T3,R ;We're not there. Punt.
RETSKP ;Return with T3, T4 set up.
;Helper routine. Get 8 bits of destination host from network address.
USEDST: SKIPL T4,T1 ;Skip if PUP, load destination
LOAD T4,ETHHST,T1 ;Load destination from IP address
HRRZS T4 ;Clear flag bits in case PUP
RET ;Return to caller
>;IFN STANSW
IFN STANSW,<
;FNDINT - find best interface after net has been selected.
;This routine addresses the problem of having two interfaces onto one network.
; Normally the Multinet code only sees one interface, not necessarily the
; optimal one. We are called by GWYLUK to ensure the best interface is chosen.
; This code assumes Stanford-style subnet routing and handles multiple MEIS
; devices only.
;Takes P1/ GWYLUK's best guess at an interface
; T1/ first hop address (either ultimate host or a local gateway)
;Returns +1 always
; P1 changed if a better interface exists
; T1,T3 preserved
FNDINT::TDZA T2,T2 ;Find best interface that is up
FNDINS::SETO T2, ;Find best interface, don't care if it's down
LOAD T4,NTDEV,(P1) ;Get type of hardware on this net
CAIN T4,NT.MEI ;If MEIS, then we do something special
SKIPGE NTSUBN(P1) ;Possible to have subnets?
RET ;No MEIS or no subnets, just return now
STKVAR <STRICTF> ;Declare local storage
MOVEM T2,STRICTF ;Set up flag word
SUBNET T4,T1 ;Get destination subnet
CAIGE T4,NPNETS ;Check if it's within range
SKIPG PUPROU-1(T4) ;Is that subnet at all accessible?
RET ;No, quietly return having done nothing
XMOVEI T2,NCTVT ;Point to the NCT vector table
FNDIN0: LOAD T2,NTLNK,(T2) ;Get next NCT in the chain
JUMPE T2,FNDIN2 ;Not directly connected to that subnet
CAME T4,NTSUBN(T2) ;Are we on that subnet?
JRST FNDIN0 ;No, try again
SKIPN NTORDY(T2) ;Is the interface up?
SKIPE STRICTF ;Yes, do we care if interface is down?
TRNA ;Up or we don't care if it's down. Use it
JRST FNDIN0 ;No, go look for another
FNDIN1: MOVE P1,T2 ;Found a directly connected interface
RET ;Return to caller
;No direct connections to that subnet. Pick best interface for routing.
FNDIN2: LOAD T4,ROUNET,(T4) ;Get subnet number of host I should route thru.
XMOVEI T2,NCTVT ;Point to the NCT vector table
FNDIN3: LOAD T2,NTLNK,(T2) ;Get next NCT in the chain
JUMPE T2,R ;Not directly connected to that subnet
CAME T4,NTSUBN(T2) ;Are we on that subnet?
JRST FNDIN3 ;No, try again
SKIPN NTORDY(T2) ;Is interface up?
SKIPE STRICTF ;No, do we care?
JRST FNDIN1 ;Up or we don't care if it's down. Use it.
JRST FNDIN3 ;Interface is down, try for a better one
ENDSV.
>;IFN STANSW
TNXEND
END