-- RouterImpl.mesa (last edited by: BLyon on: March 21, 1981 11:53 AM)
-- Function: The implementation module for the Pilot OISCP Router switch.
DIRECTORY
BufferDefs USING [OisBuffer],
Checksums USING [SetChecksum, TestChecksum],
CommunicationInternal USING [],
CommFlags USING [doDebug, doStats, doStorms],
CommUtilDefs USING [CopyLong],
DriverDefs USING [
ChangeNumberOfInputBuffers, DriverXmitStatus, GetDeviceChain, Glitch,
MaybeGetFreeOisBuffer, Network, PutOnGlobalDoneQueue, RouterObject, SetOisRouter],
Inline USING [LowHalf],
OISCP USING [
allHostIDs, CreditReceiveOisBuffer, EnqueueOis,
MaybeGetFreeReceiveOisBufferFromPool, unknownNetID, unknownSocketID],
OISCPConstants USING [routingInformationSocket],
OISCPTypes USING [
bytesPerPktHeader, bytesPerPktText, maxBytesPerPkt, OISErrorCode, TransPortControl],
Process USING [Yield],
Router USING [
AddNetwork, FindNetworkAndTransmit, FindDestinationRelativeNetID,
ForwardPacket, RemoveNetwork, RoutingInformationPacket, RoutingTableOn,
RoutingTableOff, SocketTable, StateChanged, XmitStatus],
SocketInternal USING [SocketHandle],
SpecialCommunication USING [RoutersFunction],
SpecialSystem USING [
broadcastHostNumber, GetProcessorID, HostNumber, NetworkAddress, nullNetworkNumber,
NetworkNumber, SocketNumber],
StatsDefs USING [StatIncr],
System USING [GetClockPulses];
RouterImpl: MONITOR LOCKS socketRouterLock
IMPORTS
BufferDefs, Checksums, CommUtilDefs, DriverDefs, Inline, OISCP,
Process, Router, SpecialSystem, StatsDefs, System
EXPORTS BufferDefs, CommunicationInternal, OISCP, Router
SHARES BufferDefs =
BEGIN OPEN DriverDefs, OISCP, OISCPTypes, SocketInternal, StatsDefs;
-- Many of these variables must eventually live in outerspace so that multiple MDSs
-- access the same router variables. The modules in the primary MDS will have the
-- proceses and will perform the initialization of the "globals", while the others will not.
-- The lock covers both SocketImpl and RouterImpl, specifically the socket objects,
-- the socket table, and spare socket ID counter. These will all live in outerspace.
-- The monitor locks some variables on the global frame too. They can be MDS specific.
-- EXPORTed TYPEs
Network: PUBLIC TYPE = DriverDefs.Network;
-- switches and variables that don't change during execution unless for diagnostics
primaryMDS: PUBLIC BOOLEAN ← TRUE; -- we are in the primary MDS.
checkIt: PUBLIC BOOLEAN ← TRUE; -- checksums on for everybody
driverLoopback: BOOLEAN ← FALSE; -- loopback in router
stormy: BOOLEAN ← FALSE; -- storms for debugging are not on
routersFunction: PUBLIC SpecialCommunication.RoutersFunction ← vanillaRouting;
myHostID: SpecialSystem.HostNumber; -- processor ID of this system element
initialSpareSocketID: SpecialSystem.SocketNumber = [1001];
initialTransportControl: OISCPTypes.TransPortControl =
[trace: FALSE, filler: 0, hopCount: 0];
-- oiscp router object for the dispatcher. There will only be one for all MDSs, but it
-- can live on all global frame instances or we can put it in hyperspace and have the
-- dispatcher access it via a long pointer. The former is preferable.
oiscpRouter: DriverDefs.RouterObject ←
[input: LOOPHOLE[ReceivePacket], broadcast: LOOPHOLE[SendBroadcastPacketToCorrectNet],
addNetwork: Router.AddNetwork, removeNetwork: Router.RemoveNetwork,
stateChanged: Router.StateChanged];
-- monitor protected data.
-- parameters for killing packets for debugging
lightning: INTEGER ← 30;
bolt: INTEGER ← 10;
-- I think only the following need be in outerspace, accesible via a pointer since these
-- will be touched by multiple MDS processes via their copy of RouterImpl and SocketImpl.
socketRouterLock: PUBLIC MONITORLOCK;
-- lock for the router and all the sockets.
-- Some day the socketIDs in use will be remembered across wrap around, and maybe
-- the rebooting of Pilot.
spareSocketID: SpecialSystem.SocketNumber;
-- socket table
socketTable: Router.SocketTable;
-- various Glitches generated by the router
IllegalOisPktLength: ERROR = CODE;
-- Cool Procedures
-- This procedure assigns a temporary socket number in an SpecialSystem.NetworkAddress.
-- Some day the active socket numbers in use will be kept around, so that on wrap
-- around an unused number will be assigned. When the system element is connected to
-- more than one network, this procedure must return a list of SpecialSystem.NetworkAddress.
AssignOisAddress: PUBLIC ENTRY PROCEDURE
RETURNS [localAddr: SpecialSystem.NetworkAddress] =
BEGIN
localAddr ← [net: Router.FindDestinationRelativeNetID[SpecialSystem.nullNetworkNumber],
host: myHostID, socket: spareSocketID];
IF (spareSocketID ← [spareSocketID + 1]) = SpecialSystem.SocketNumber[0] THEN
spareSocketID ← initialSpareSocketID;
END; -- AssignOisAddress
-- This procedure is just like the previous one except that the network number is relative
-- to the destination network. That is, we pick that one of our locally connected
-- networks that is the best way to get to destNet, with the hope that it is the best
-- way to get from destNet to us.
AssignDestinationRelativeOisAddress: PUBLIC ENTRY PROCEDURE [destNet: SpecialSystem.NetworkNumber]
RETURNS [localAddr: SpecialSystem.NetworkAddress] =
BEGIN
localAddr ←
[net: Router.FindDestinationRelativeNetID[destNet], host: myHostID,
socket: spareSocketID];
IF (spareSocketID ← [spareSocketID + 1]) = SpecialSystem.SocketNumber[0] THEN
spareSocketID ← initialSpareSocketID;
END; -- AssignDestinationRelativeOisAddress
-- This procedure tells the OISCP Router about a new socket.
AddSocket: PUBLIC ENTRY PROCEDURE [sH: SocketHandle] =
BEGIN
MaybeIncreaseDriversBuffers: PROCEDURE = INLINE
BEGIN
previousSH: SocketHandle ← socketTable.first;
UNTIL previousSH = NIL DO
IF previousSH.pool.total > 0 THEN RETURN;
previousSH ← previousSH.next;
ENDLOOP;
DriverDefs.ChangeNumberOfInputBuffers[TRUE]; -- TRUE => increase
END;
-- add new socket to the head of the table
IF sH.pool.total > 0 THEN MaybeIncreaseDriversBuffers[];
sH.next ← socketTable.first;
socketTable.first ← sH;
socketTable.length ← socketTable.length + 1;
END; -- AddSocket
-- This procedure removes a socket from the OISCP Router's tables.
RemoveSocket: PUBLIC ENTRY PROCEDURE [sH: SocketHandle] =
BEGIN
MaybeDecreaseDriversBuffers: PROCEDURE = INLINE
BEGIN
previousSH ← socketTable.first;
UNTIL previousSH = NIL DO
IF previousSH.pool.total > 0 THEN RETURN;
previousSH ← previousSH.next;
ENDLOOP;
DriverDefs.ChangeNumberOfInputBuffers[FALSE]; -- FALSE => decrease
END;
previousSH: SocketHandle;
IF socketTable.first = sH THEN socketTable.first ← sH.next
ELSE
BEGIN
previousSH ← socketTable.first;
UNTIL previousSH = NIL DO
IF previousSH.next = sH THEN BEGIN previousSH.next ← sH.next; EXIT; END;
previousSH ← previousSH.next;
ENDLOOP;
END;
socketTable.length ← socketTable.length - 1;
IF sH.pool.total > 0 THEN MaybeDecreaseDriversBuffers[];
END; -- RemoveSocket
-- This is not an entry procedure because we change it only for debugging and can
-- live with a race condition.
SetOisStormy: PUBLIC PROCEDURE [new: BOOLEAN] = BEGIN stormy ← new; END;
-- SetOisStormy
-- This is not an entry procedure because we change it only for debugging and can
-- live with a race condition.
SetOisCheckit: PUBLIC PROCEDURE [new: BOOLEAN] = BEGIN checkIt ← new; END;
-- SetOisCheckIt
-- This is not an entry procedure because we change it only for debugging and can
-- live with a race condition.
SetOisDriverLoopback: PUBLIC PROCEDURE [new: BOOLEAN] =
BEGIN driverLoopback ← new; END; -- SetOisDriverLoopback
-- This procedure returns the processor ID of this machine.
FindMyHostID: PUBLIC PROCEDURE RETURNS [SpecialSystem.HostNumber] =
BEGIN RETURN[myHostID]; END; -- FindMyHostID
GetOisPacketTextLength: PUBLIC PROCEDURE [b: BufferDefs.OisBuffer] RETURNS [CARDINAL] =
BEGIN RETURN[b.ois.pktLength - bytesPerPktHeader]; END;
-- GetOisPacketTextLength
SetOisPacketTextLength: PUBLIC PROCEDURE [b: BufferDefs.OisBuffer, len: CARDINAL] =
BEGIN
IF len IN [0..bytesPerPktText] THEN
b.ois.pktLength ← len + bytesPerPktHeader
ELSE IF CommFlags.doDebug THEN Glitch[IllegalOisPktLength];
END; -- SetOisPacketTextLength
SetOisPacketLength: PUBLIC PROCEDURE [b: BufferDefs.OisBuffer, len: CARDINAL] =
BEGIN
IF len IN [bytesPerPktHeader..maxBytesPerPkt] THEN b.ois.pktLength ← len
ELSE IF CommFlags.doDebug THEN Glitch[IllegalOisPktLength];
END; -- SetOisPacketLength
-- Hot Procedures
-- This procedure transmits a packet over a locally connected network.
-- The procedure assumes that all fields of the buffer have been filled in appropriately,
-- except the encapsulation and buffer length which depend on the network. If the
-- packet is destined for a local socket and we do NOT want to do loopback at the
-- driver or at the network, then it gets looped back here. Broadcast
-- packets are NOT delivered to the source socket.
-- Packets are no longer copied into system buffers.
-- The caller owns the buffer. The buffer is asynchronously sent and retruned to the
-- caller process by the dispatcher using b.requeueProcedure.
SendPacket: PUBLIC PROCEDURE [b: BufferDefs.OisBuffer] =
BEGIN
IF CommFlags.doStorms AND stormy AND PacketHit[] THEN
BEGIN
DriverDefs.PutOnGlobalDoneQueue[b];
RETURN; -- for debugging only
END;
IF b.ois.destination.host = myHostID AND
NOT driverLoopback THEN
-- packet is for a local socket; broadcast packets are not delivered locally
BEGIN
IF NOT DeliveredToLocalSocket[b, TRUE] THEN -- TRUE -> copy this buffer
BEGIN
nullNetwork: Network = NIL; -- because of EXPORTed TYPEs bug
-- no socket
IF CommFlags.doStats THEN StatIncr[statJunkOisForUsNoLocalSocket];
b.network ← nullNetwork; SendErrorPacket[b, noSocketOisErrorCode, 0];
END;
-- we requeue here because we shorted the drivers and dispatcher.
-- we Yield here to prevent local communication from using all of the cycles.
DriverDefs.PutOnGlobalDoneQueue[b];
Process.Yield[];
END
ELSE
-- packet is for a remote machine
BEGIN
-- If the destination net is inaccessible then we will have suffered the overhead of
-- computing a checksum, but we don't expect inaccessible nets that often.
-- set the checksum if appropriate
b.ois.transCntlAndPktTp.transportControl ← initialTransportControl;
IF checkIt THEN Checksums.SetChecksum[b] ELSE b.ois.checksum ← 177777B;
[] ← Router.FindNetworkAndTransmit[b];
END;
END; -- SendPacket
-- This procedure is called by the Dispatcher when it sees a valid ois packet in a system
-- buffer. The procedure checks the checksum field and then routes the packet to a
-- local socket. If this is an internetwork router, then the packets are forwarded over
-- a suitable network. We now own this packet.
ReceivePacket: PUBLIC PROCEDURE [b: BufferDefs.OisBuffer] =
BEGIN
badChecksum: BOOLEAN;
incomingNet: Network;
destHost: SpecialSystem.HostNumber ← b.ois.destination.host;
broadcastPacket: BOOLEAN ← FALSE;
IF b.ois.pktLength < OISCPTypes.bytesPerPktHeader THEN
BEGIN
IF CommFlags.doStats THEN StatIncr[statOisDiscarded];
DriverDefs.PutOnGlobalDoneQueue[b]; -- done with this packet
RETURN;
END;
IF (badChecksum ← IF checkIt THEN NOT Checksums.TestChecksum[b] ELSE FALSE)
THEN
-- hardware says ok, but bad end-to-end software checksum.
BEGIN
IF CommFlags.doStats THEN
BEGIN
StatIncr[statReceivedBadOisChecksum];
StatIncr[statOisDiscarded];
END;
DriverDefs.PutOnGlobalDoneQueue[b]; -- done with this packet
RETURN;
END;
-- packet is in good shape, route it.
IF CommFlags.doStorms AND stormy AND PacketHit[] THEN
BEGIN DriverDefs.PutOnGlobalDoneQueue[b]; RETURN; END; -- for debugging only
incomingNet ← b.network;
IF destHost = myHostID
OR ((broadcastPacket←(destHost = allHostIDs))
AND (incomingNet.netNumber = b.ois.destination.net)
OR (b.ois.destination.net = SpecialSystem.nullNetworkNumber)) THEN
BEGIN -- incomming packet for us (we may have broadcast it)
IF NOT DeliveredToLocalSocket[b, FALSE] THEN
-- FALSE -> do not copy this buffer, but deliver it
BEGIN
-- routing information socket is part of router in another module
IF b.ois.destination.socket = OISCPConstants.routingInformationSocket THEN
Router.RoutingInformationPacket[b] -- we still own this packet!
ELSE
BEGIN -- packet for unknown socket
IF NOT broadcastPacket THEN
BEGIN
SendErrorPacket[b, noSocketOisErrorCode, 0];
IF CommFlags.doStats THEN StatIncr[statJunkOisForUsNoLocalSocket];
END
ELSE IF CommFlags.doStats THEN StatIncr[statJunkBroadcastOis]
END;
DriverDefs.PutOnGlobalDoneQueue[b]; -- done with this packet
END;
END
ELSE SELECT TRUE FROM
routersFunction=interNetworkRouting =>
BEGIN
Router.ForwardPacket[b]; -- dispatcher returns to system pool
END;
b.ois.destination.socket=OISCPConstants.routingInformationSocket =>
BEGIN
Router.RoutingInformationPacket[b]; -- we still own this packet!
DriverDefs.PutOnGlobalDoneQueue[b];
END;
ENDCASE =>
BEGIN
IF CommFlags.doStats THEN StatIncr[statOisDiscarded];
DriverDefs.PutOnGlobalDoneQueue[b]; -- we got the packet when we shouldn't have!
END;
END; -- ReceivePacket
-- Hot, except should really not exist; therefor cold?
-- This procedure attempts to hit a packet with a bolt of lightening, and if it succeeds,
-- then it returns true else false. The caller dispenses with the buffer.
PacketHit: ENTRY PROCEDURE RETURNS [BOOLEAN] =
BEGIN
IF (lightning ← lightning + 1) > bolt OR lightning < 0 THEN
BEGIN
IF lightning > bolt THEN
BEGIN
IF bolt > 100 THEN
BEGIN
randLong: LONG CARDINAL ← System.GetClockPulses[];
rand: CARDINAL ← Inline.LowHalf[randLong];
lightning ← -INTEGER[rand MOD 20B];
bolt ← 10;
END
ELSE BEGIN lightning ← 0; bolt ← bolt + 1; END;
END;
IF CommFlags.doStats THEN StatIncr[statZappedP];
RETURN[TRUE];
END
ELSE RETURN[FALSE];
END; -- PacketHit
-- This procedure finds a local socket object to deliver the packet to, and if it succeeds,
-- then it returns true else false. Caller retains ownership of buffer if useCopy is true
-- or return is false; caller loses buffer ownership if NOT useCopy and return is true.
DeliveredToLocalSocket: ENTRY PROCEDURE [b: BufferDefs.OisBuffer, useCopy: BOOLEAN]
RETURNS [BOOLEAN] =
BEGIN
ENABLE UNWIND => NULL;
destSocket: SpecialSystem.SocketNumber ← b.ois.destination.socket;
sH, prevSH: SocketHandle;
-- find the correct socket for this packet
FOR sH ← (prevSH ← socketTable.first), sH.next UNTIL sH = NIL DO
IF sH.localAddr.socket = destSocket THEN
BEGIN
IF useCopy THEN EnqueueCopyOfNewInput[sH, b] ELSE EnqueueNewInput[sH, b];
-- do some dynamic socket ordering before returning; rearange the list only if
-- sH was not in the first two entries of the list.
IF prevSH # socketTable.first THEN
BEGIN
prevSH.next ← sH.next; -- this removes sH from the list
sH.next ← socketTable.first;
socketTable.first ← sH; -- this puts sH at head of list
END;
RETURN[TRUE];
END;
prevSH ← sH;
ENDLOOP;
RETURN[FALSE];
END; -- DeliveredToLocalSocket
-- This procedure enqueues a new input packet at the socket object.
-- The incoming buffer is from a network driver and NOT a local socket.
-- The caller of this routine relinquishes ownership of this buffer.
EnqueueNewInput: INTERNAL PROCEDURE [sH: SocketHandle, b: BufferDefs.OisBuffer] =
INLINE
BEGIN
IF (sH.channelState = aborted) OR NOT
(OISCP.CreditReceiveOisBuffer[sH.pool, b]) THEN
BEGIN
IF CommFlags.doStats THEN StatsDefs.StatIncr[statOisInputQueueOverflow];
DriverDefs.PutOnGlobalDoneQueue[b];
RETURN;
END;
b.status ← LOOPHOLE[Router.XmitStatus[goodCompletion]];
EnqueueOis[@sH.completedUserGetQueue, b];
BROADCAST sH.newUserInput;
END; -- EnqueueNewInput
-- This procedure enqueues a new input packet at the socket object.
-- The incoming buffer is only from a local socket.
-- The caller of this routine retains ownership of this buffer.
EnqueueCopyOfNewInput: INTERNAL PROCEDURE [
sH: SocketHandle, b: BufferDefs.OisBuffer] = INLINE
BEGIN
getBuffer: BufferDefs.OisBuffer ←
IF sH.channelState = aborted THEN NIL
ELSE MaybeGetFreeReceiveOisBufferFromPool[sH.pool];
-- Copy b into the first OisBuffer on the pendingGetQueue, if there is one.
IF (getBuffer # NIL) THEN
BEGIN
getBuffer.status ← LOOPHOLE[Router.XmitStatus[goodCompletion]];
-- assume always good
-- getBuffer is full sized OisBuffer, therefore no need to check length
CommUtilDefs.CopyLong[
from: @b.ois.checksum, nwords: (b.ois.pktLength + 1)/2,
to: @getBuffer.ois.checksum];
EnqueueOis[@sH.completedUserGetQueue, getBuffer];
BROADCAST sH.newUserInput;
END
ELSE IF CommFlags.doStats THEN StatsDefs.StatIncr[statOisInputQueueOverflow];
-- funny name
END; -- EnqueueNewLocalInput
-- This procedure causes a broadcast packet to be sent over all networks.
BroadcastThisPacket: PUBLIC PROCEDURE [b: BufferDefs.OisBuffer] =
BEGIN
network: Network;
IF CommFlags.doStats THEN StatIncr[statOisBroadcast];
b.allNets ← TRUE; -- this is where it gets turned on
b.ois.destination.host ← SpecialSystem.broadcastHostNumber;
b.network ← network ← DriverDefs.GetDeviceChain[];
IF network = NIL THEN
BEGIN
DriverDefs.PutOnGlobalDoneQueue[b];
IF CommFlags.doStats THEN StatsDefs.StatIncr[statOisSentNowhere];
RETURN;
END;
SendBroadcastPacketToCorrectNet[b];
END; -- BroadcastThisPacket
-- This procedure causes a broadcast packet to be sent out over the right network.
SendBroadcastPacketToCorrectNet: PUBLIC PROCEDURE [b: BufferDefs.OisBuffer] =
BEGIN
network: Network ← b.network;
IF ~network.alive OR (b.bypassZeroNet AND network.netNumber = [0, 0]) THEN
BEGIN DriverDefs.PutOnGlobalDoneQueue[b]; RETURN; END;
-- goes (slowly) around in circles
b.ois.destination.net ← b.ois.source.net ← network.netNumber;
b.ois.source.host ← myHostID;
IF checkIt THEN Checksums.SetChecksum[b] ELSE b.ois.checksum ← 177777B;
LOOPHOLE[b.status, DriverDefs.DriverXmitStatus] ← goodCompletion;
network.encapsulateOis[b, SpecialSystem.broadcastHostNumber];
network.sendBuffer[b];
END; -- SendBroadcastPacketToCorrectNet
-- This procedure generates and sends an error packet. All or most of the
-- offending packet is copied into the the error packet. The caller of this
-- Procedure still owns offendingPkt.
SendErrorPacket: PUBLIC PROCEDURE [offendingPkt: BufferDefs.OisBuffer, errCode: OISCPTypes.OISErrorCode, errParm: CARDINAL] =
BEGIN
net: Network = offendingPkt.network;
b: BufferDefs.OisBuffer;
offenseLen: CARDINAL;
IF offendingPkt.ois.transCntlAndPktTp.packetType=error THEN RETURN; -- don't send errors about errors
IF (b ← DriverDefs.MaybeGetFreeOisBuffer[])=NIL THEN RETURN; -- give up!
b.ois.destination ← offendingPkt.ois.source;
b.ois.source ← [ IF net=NIL THEN OISCP.unknownNetID ELSE net.netNumber,
myHostID, OISCP.unknownSocketID];
b.ois.transCntlAndPktTp ← [initialTransportControl, error];
b.ois.errorType ← errCode;
b.ois.errorParameter ← errParm;
offenseLen ← MIN[offendingPkt.ois.pktLength, OISCPTypes.bytesPerPktText-4]; -- four is for errorType and errorParameter.
CommUtilDefs.CopyLong[@offendingPkt.ois, (offenseLen+1)/2, @b.ois.errorBody];
SetOisPacketTextLength[b, offenseLen+4];
SendPacket[b];
END; -- SendErrorPacket
--Cold Procedures
-- This procedure turns the router on. The Communication software is written with the
-- idea of eventually turning the code on and off during execution, and so we should
-- get the latest values of netID and hostID when being turned back on.
OisRouterOn: PUBLIC PROCEDURE =
BEGIN
OisRouterActivate[];
Router.RoutingTableOn[];
DriverDefs.SetOisRouter[@oiscpRouter];
END; -- OisRouterOn
OisRouterActivate: ENTRY PROCEDURE = INLINE
BEGIN
myHostID ← SpecialSystem.GetProcessorID[];
IF primaryMDS THEN socketTable ← [length: 0, first: NIL];
END; -- OisRouterActivate
OisRouterOff: PUBLIC PROCEDURE =
BEGIN
DriverDefs.SetOisRouter[NIL];
OisRouterDeactivate[];
Router.RoutingTableOff[];
END; -- OisRouterOff
OisRouterDeactivate: ENTRY PROCEDURE = INLINE
BEGIN
-- cleanup the socket table.
--IF primaryMDS THEN
END; -- OisRouterDeactivate
--Cold
-- initialization
IF primaryMDS THEN spareSocketID ← initialSpareSocketID;
END. -- RouterImpl module.
LOG
Time: January 19, 1980 4:05 PM By: Dalal Action: Split OISCPRouter into two.
Time: January 21, 1980 6:07 PM By: Dalal Action: one lock for SocketImpl and RouterImpl.
Time: March 13, 1980 4:55 PM By: BLyon Action: modified SendPacket.
Time: March 18, 1980 4:09 PM By: BLyon Action: Modified EnqueueNewInput where it gets an input buffer.
Time: May 12, 1980 6:38 PM By: BLyon Action: Put checksum into microcode (switched order parameters too).
Time: May 16, 1980 10:07 AM PM By: BLyon Action: Removed all ShortenPointer to allow multiple MDS.
Time: June 30, 1980 1:02 PM By: BLyon Action: Checkit init to FALSE instead of TRUE..
Time: July 22, 1980 11:03 AM By: BLyon Action: Checkit changed back to TRUE; checksums stuff put in seperate modules; we now receive out own broadcasts.
Time: August 1, 1980 1:29 PM By: BLyon Action: replaced internetRouter by routersFunction.
Time: September 13, 1980 6:15 PM By: HGM Action: Add StateChanged.
Time: September 18, 1980 3:34 PM By: BLyon Action: AssignOisAddress puts unknownNetID in network field rather than primaryNetID.
Time: February 24, 1981 3:25 PM By: BLyon Action: put extra clause in ReceivePacket so that an INR would forward a broadcast instead of eating it with a local socket.