FediChordProtocol DEFINITIONS AUTOMATIC TAGS ::= BEGIN

NodeID ::= INTEGER (0..115792089237316195423570985008687907853269984665640564039457584007913129639935)

Domain ::= VisibleString

Partnum ::= INTEGER (0..150)

Action ::= ENUMERATED {queryID, join, leave, stabilise, ping, queryLoad}

Request ::= SEQUENCE {
	action			Action,
	requestID		INTEGER (0..4294967295),	-- arbitrarily restricting to an unsigned 32bit integer
	sender			NodeState,
	part			Partnum,	-- part number of this message, starts at 1
	finalPart		BOOLEAN,	-- flag indicating this `part` to be the last of this reuest
	actionPayload	CHOICE {
		queryIDRequestPayload		QueryIDRequestPayload,
		joinRequestPayload			JoinRequestPayload,
		leaveRequestPayload			LeaveRequestPayload,
		stabiliseRequestPayload		StabiliseRequestPayload,
		pingRequestPayload			PingRequestPayload,
		loadRequestPayload			LoadRequestPayload
		}			OPTIONAL			-- just for symmetry reasons with response, requests without a payload have no meaning
	}

-- idea: different message layouts as a way of distinguishing between
-- request and response instead of explicit flag

Response ::= SEQUENCE {
	-- requestID of the request responding to
	requestID		INTEGER (0..4294967295),	-- arbitrarily restricting to an unsigned 32bit integer
	senderID		NodeID,
	part			Partnum,
	finalPart		BOOLEAN,	-- flag indicating this `part` to be the last of this response
	action			Action,
	actionPayload	CHOICE {
		queryIDResponsePayload		QueryIDResponsePayload,
		joinResponsePayload			JoinResponsePayload,
		leaveResponsePayload		LeaveResponsePayload,
		stabiliseResponsePayload	StabiliseResponsePayload,
		pingResponsePayload			PingResponsePayload,
		loadResponsePayload			LoadResponsePayload
		}			OPTIONAL			-- no payload when just ACKing a previous request
	}

NodeState ::= SEQUENCE {
	nid				NodeID,
	domain			Domain,
	ipAddr			OCTET STRING (SIZE(16)),
	dhtPort			INTEGER,
	servicePort		INTEGER,
	vServerID		INTEGER (0..255)
	}

CacheEntry ::= SEQUENCE {
	node			NodeState,
	-- use POSIX time stamp, as DATE-TIME isn't supported by the Haskell lib
	timestamp		INTEGER
	}

NodeCache ::= SEQUENCE OF CacheEntry

JoinRequestPayload ::= NULL

JoinResponsePayload ::= SEQUENCE {
	successors		SEQUENCE OF NodeState,
	predecessors	SEQUENCE OF NodeState,
	cache			NodeCache
	}

QueryResult ::= ENUMERATED { found, forward }

QueryIDRequestPayload ::= SEQUENCE {
	targetID		NodeID,
	lBestNodes		INTEGER
	}

QueryIDResponsePayload ::= SEQUENCE {
	result			QueryResult,
	nodeData		CHOICE {NodeState, NodeCache}
	}

StabiliseRequestPayload ::= NULL

StabiliseResponsePayload ::= SEQUENCE {
	successors		SEQUENCE OF NodeState,
	predecessors	SEQUENCE OF NodeState
	-- ToDo: transfer of handled key data, if newly responsible for it
	}

LeaveRequestPayload ::= SEQUENCE {
	successors		SEQUENCE OF NodeState,
	predecessors	SEQUENCE OF NodeState,
	doMigration		BOOLEAN
	}

LeaveResponsePayload ::= NULL	-- just a confirmation

PingRequestPayload ::= NULL		-- do not include a node/ vserver ID, so that
								-- the node has to respond with all active ones

-- learning all active vserver IDs handled by the server at once
PingResponsePayload ::= SEQUENCE OF NodeState

LoadRequestPayload ::= SEQUENCE {
	lowerBound		NodeID,
	upperBound		NodeID
	}

LoadResponsePayload ::= SEQUENCE {
	loadSum					REAL,
	remainingLoadTarget		REAL
	}

END