DIRECTORY
BufferDefs USING[ PupBuffer ],
PrincOps USING[ PsbIndex ],
PupTypes USING[ PupHostID, PupNetID, PupSocketID ],
RPCLupine USING[ DataLength, Dispatcher, RPCPkt ],
RPCPrivate USING[ rpcSocket ];
Header:
TYPE =
MACHINE
DEPENDENT
RECORD[
length (0:0..14): [0..77777B],
oddByte (0:15..15): { no(0), yes(1) },
type (1): PktType,
destPSB (2): PrincOps.PsbIndex,-- field has 6 extra bits
srcePSB (3): PrincOps.PsbIndex,-- field has 6 extra bits
destHost (4): Machine,
destSoc (5): PupTypes.PupSocketID,
srceHost (7): Machine,
srceSoc (8): PupTypes.PupSocketID,
end of standard Pup header
conv (10): PktConversationID,
For secure conversations, the remainder of the packet must be encrypted
pktID (12): PktID,
call (16):
SELECT
OVERLAID *
FROM
calling => [
dispatcher (16): DispatcherDetails],
responding => [
outcome (16): Outcome,
fill (17): ARRAY[SIZE[Outcome]..SIZE[DispatcherDetails]) OF WORD],
ENDCASE ];
PktType:
TYPE =
MACHINE
DEPENDENT
RECORD[
-- "type" word of a Pup --
transport (0:0..7): [0..255], -- should be zero before sending --
subType (0:8..10): { rpc(3B), (7B) },
eom (0:11..11): { end(0), notEnd(1) },
ack (0:12..12): { dontAck(0), pleaseAck(1) },
class (0:13..15): { call(0), data(1), ack(2), rfa(4), (7) } ];
Mapping from Pup pkt types to RPC pkt types:
140B = [end, dontAck, call ]
141B = [end, dontAck, data ]
142B = [, dontAck, ack ] (also 162B)
143B = unused (also 163B)
144B = [, dontAck, rfa ] (also 164B)
150B = [end, pleaseAck, call ]
151B = [end, pleaseAck, data ]
152B = [, pleaseAck, ack ] (also 172B)
153B = unused (also 173B)
154B = [, pleaseAck, rfa ] (also 174B)
160B = [notEnd, dontAck, call ]
161B = [notEnd, dontAck, data ]
170B = [notEnd, pleaseAck, call ]
171B = [notEnd, pleaseAck, data ]
pktLengthOverhead: RPCLupine.DataLength =
SIZE[Header] + 1
--checksum--;
Difference between RPCLupine.DataLength and transmitted Pup length for unencrypted packets
Machine:
TYPE =
MACHINE
DEPENDENT
RECORD[
Unambiguous name of a host
net: PupTypes.PupNetID,
host: PupTypes.PupHostID ];
HostConversationID:
TYPE =
MACHINE
DEPENDENT
RECORD[
Host-relative ID of a conversation; unique for all time
ls(0): CARDINAL,
ms(1): [0..77777B] ];
ConversationID:
TYPE =
RECORD[
Absolute ID of a conversation; unique for all hosts and all time
originator: Machine,
count: HostConversationID];
PktConversationID:
TYPE =
MACHINE
DEPENDENT
RECORD[
Same as ConversationID, but abbreviated for within a packet. Assumes originator is always caller or callee
ls(0): CARDINAL,
originator(1:0..0): { caller, callee },
ms(1:1..15): [0..77777B] ];
ConnectionID:
TYPE =
MACHINE
DEPENDENT
RECORD[
Uniquely identifies an independent sequence of calls
conv(0): PktConversationID,
caller(2): Machine,
activity(3): PrincOps.PsbIndex ];
CallCount:
TYPE =
LONG
CARDINAL;
[ConnectionID,CallCount] uniquely identifies call for all hosts and time
PktID:
TYPE =
MACHINE
DEPENDENT
RECORD[
[ConversationID,PktID] uniquely identifies pkt for all hosts and time.
activity(0): PrincOps.PsbIndex,-- field has 6 extra bits--
callSeq(1): CallCount,
pktSeq(3): CARDINAL ];
Outcome:
TYPE =
MACHINE
DEPENDENT {
-- possible responses to call or signal --
result(0), -- normal --
unbound(1), -- dispatcher not known --
signal(2), -- signal propagation --
unwind(3), -- signal is unwinding --
protocol(4), -- stub protocol error detected --
(LAST[CARDINAL]) -- room for expansion? --
};
DispatcherDetails:
TYPE =
MACHINE
DEPENDENT
RECORD[
mds: CARDINAL, -- top half of dispatcher's MDS base address --
dispatcherID: DispatcherID, -- exporter-relative UID of interface instance --
dispatcherHint: ExportHandle -- hint to exporter host's export table -- ];
DispatcherID: TYPE = LONG CARDINAL;
noDispatcher: DispatcherID = 0;
ExportHandle: TYPE = CARDINAL;
SetupResponse:
PROC[header:
LONG
POINTER
TO Header] =
INLINE
BEGIN
header.destHost ← header.srceHost;
header.destSoc ← RPCPrivate.rpcSocket;
header.destPSB ← header.srcePSB;
header.outcome ← result;
END;
PktExchangeState: TYPE = { receiving, sending, call, endCall, authReq };
PktExchange:
PROC[inPkt: RPCLupine.RPCPkt, length: RPCLupine.DataLength,
maxlength: RPCLupine.DataLength,
state: PktExchangeState,
signalHandler: RPCLupine.Dispatcher ← NIL]
RETURNS[newPkt: BOOLEAN, newLength: RPCLupine.DataLength];
Reliable transmission of given packet, and receipt of next packet; "newLength" is data length of incoming packet, if any.
IdleReceive:
PROC[pkt: RPCLupine.RPCPkt, maxlength:
CARDINAL];
Returns when new packet arrives; "maxlength" is number of words in the pkt buffer starting from pkt.header (total, including all overheads)
EnqueueAgain:
PROC[b: BufferDefs.PupBuffer];
Dispatches packet to appropriate process; used by idler processes to requeue pkt that had incorrect destPSB.