nwaku/waku/waku_relay/protocol.nim

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## Waku Relay module. Thin layer on top of GossipSub.
##
## See https://github.com/vacp2p/specs/blob/master/specs/waku/v2/waku-relay.md
## for spec.
when (NimMajor, NimMinor) < (1, 4):
{.push raises: [Defect].}
else:
{.push raises: [].}
import
stew/results,
sequtils,
chronos,
chronicles,
metrics,
libp2p/multihash,
libp2p/protocols/pubsub/pubsub,
libp2p/protocols/pubsub/gossipsub,
libp2p/protocols/pubsub/rpc/messages,
libp2p/stream/connection,
libp2p/switch
import
../waku_core,
./message_id
logScope:
topics = "waku relay"
const
WakuRelayCodec* = "/vac/waku/relay/2.0.0"
# see: https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.1.md#overview-of-new-parameters
const TopicParameters = TopicParams(
topicWeight: 1,
# p1: favours peers already in the mesh
timeInMeshWeight: 0.01,
timeInMeshQuantum: 1.seconds,
timeInMeshCap: 10.0,
# p2: rewards fast peers
firstMessageDeliveriesWeight: 1.0,
firstMessageDeliveriesDecay: 0.5,
firstMessageDeliveriesCap: 10.0,
# p3: penalizes lazy peers. safe low value
meshMessageDeliveriesWeight: 0.0,
meshMessageDeliveriesDecay: 0.0,
meshMessageDeliveriesCap: 0,
meshMessageDeliveriesThreshold: 0,
meshMessageDeliveriesWindow: 0.milliseconds,
meshMessageDeliveriesActivation: 0.seconds,
# p3b: tracks history of prunes
meshFailurePenaltyWeight: 0.0,
meshFailurePenaltyDecay: 0.0,
# p4: penalizes invalid messages. highly penalize
# peers sending wrong messages
invalidMessageDeliveriesWeight: -100.0,
invalidMessageDeliveriesDecay: 0.5
)
# see: https://rfc.vac.dev/spec/29/#gossipsub-v10-parameters
const GossipsubParameters = GossipSubParams(
explicit: true,
pruneBackoff: chronos.minutes(1),
unsubscribeBackoff: chronos.seconds(5),
floodPublish: true,
gossipFactor: 0.25,
d: 6,
dLow: 4,
dHigh: 8,
dScore: 6,
dOut: 3,
dLazy: 6,
heartbeatInterval: chronos.seconds(1),
historyLength: 6,
historyGossip: 3,
fanoutTTL: chronos.minutes(1),
seenTTL: chronos.minutes(2),
# no gossip is sent to peers below this score
gossipThreshold: -100,
# no self-published msgs are sent to peers below this score
publishThreshold: -1000,
# used to trigger disconnections + ignore peer if below this score
graylistThreshold: -10000,
# grafts better peers if the mesh median score drops below this. unset.
opportunisticGraftThreshold: 0,
# how often peer scoring is updated
decayInterval: chronos.seconds(12),
# below this we consider the parameter to be zero
decayToZero: 0.01,
# remember peer score during x after it disconnects
retainScore: chronos.minutes(10),
# p5: application specific, unset
appSpecificWeight: 0.0,
# p6: penalizes peers sharing more than threshold ips
ipColocationFactorWeight: -50.0,
ipColocationFactorThreshold: 5.0,
# p7: penalizes bad behaviour (weight and decay)
behaviourPenaltyWeight: -10.0,
behaviourPenaltyDecay: 0.986,
# triggers disconnections of bad peers aka score <graylistThreshold
disconnectBadPeers: true
)
type
WakuRelayResult*[T] = Result[T, string]
WakuRelayHandler* = proc(pubsubTopic: PubsubTopic, message: WakuMessage): Future[void] {.gcsafe, raises: [Defect].}
WakuValidatorHandler* = proc(pubsubTopic: PubsubTopic, message: WakuMessage): Future[ValidationResult] {.gcsafe, raises: [Defect].}
WakuRelay* = ref object of GossipSub
# a map of PubsubTopic's => seq[WakuValidatorHandler] that are
# called in order every time a message is received on a given pubsub topic
wakuValidators: Table[PubsubTopic, seq[WakuValidatorHandler]]
# a map that stores whether the ordered validator has been inserted
# for a given PubsubTopic
validatorInserted: Table[PubsubTopic, bool]
proc initProtocolHandler(w: WakuRelay) =
proc handler(conn: Connection, proto: string) {.async.} =
## main protocol handler that gets triggered on every
## connection for a protocol string
## e.g. ``/wakusub/0.0.1``, etc...
debug "Incoming WakuRelay connection", connection=conn, protocol=proto
try:
await w.handleConn(conn, proto)
except CancelledError:
# This is top-level procedure which will work as separate task, so it
# do not need to propogate CancelledError.
error "Unexpected cancellation in relay handler", conn=conn, error=getCurrentExceptionMsg()
except CatchableError:
error "WakuRelay handler leaks an error", conn=conn, error=getCurrentExceptionMsg()
# XXX: Handler hijack GossipSub here?
w.handler = handler
w.codec = WakuRelayCodec
proc new*(T: type WakuRelay, switch: Switch): WakuRelayResult[T] =
var w: WakuRelay
try:
w = WakuRelay.init(
switch = switch,
anonymize = true,
verifySignature = false,
sign = false,
triggerSelf = true,
msgIdProvider = defaultMessageIdProvider,
maxMessageSize = MaxWakuMessageSize,
parameters = GossipsubParameters
)
procCall GossipSub(w).initPubSub()
w.initProtocolHandler()
except InitializationError:
return err("initialization error: " & getCurrentExceptionMsg())
return ok(w)
proc addValidator*(w: WakuRelay,
topic: varargs[string],
handler: WakuValidatorHandler) {.gcsafe.} =
for t in topic:
w.wakuValidators.mgetOrPut(t, @[]).add(handler)
method start*(w: WakuRelay) {.async.} =
debug "start"
await procCall GossipSub(w).start()
method stop*(w: WakuRelay) {.async.} =
debug "stop"
await procCall GossipSub(w).stop()
proc isSubscribed*(w: WakuRelay, topic: PubsubTopic): bool =
GossipSub(w).topics.hasKey(topic)
proc subscribedTopics*(w: WakuRelay): seq[PubsubTopic] =
return toSeq(GossipSub(w).topics.keys())
proc generateOrderedValidator*(w: WakuRelay): auto {.gcsafe.} =
# rejects messages that are not WakuMessage
let wrappedValidator = proc(pubsubTopic: string,
message: messages.Message): Future[ValidationResult] {.async.} =
# can be optimized by checking if the message is a WakuMessage without allocating memory
# see nim-libp2p protobuf library
let msgRes = WakuMessage.decode(message.data)
if msgRes.isErr():
return ValidationResult.Reject
let msg = msgRes.get()
# now sequentially validate the message
if w.wakuValidators.hasKey(pubsubTopic):
for validator in w.wakuValidators[pubsubTopic]:
let validatorRes = await validator(pubsubTopic, msg)
if validatorRes != ValidationResult.Accept:
return validatorRes
return ValidationResult.Accept
return wrappedValidator
proc subscribe*(w: WakuRelay, pubsubTopic: PubsubTopic, handler: WakuRelayHandler): TopicHandler =
debug "subscribe", pubsubTopic=pubsubTopic
# we need to wrap the handler since gossipsub doesnt understand WakuMessage
let wrappedHandler =
proc(pubsubTopic: string, data: seq[byte]): Future[void] {.gcsafe, raises: [].} =
let decMsg = WakuMessage.decode(data)
if decMsg.isErr():
# fine if triggerSelf enabled, since validators are bypassed
error "failed to decode WakuMessage, validator passed a wrong message", error = decMsg.error
let fut = newFuture[void]()
fut.complete()
return fut
else:
return handler(pubsubTopic, decMsg.get())
# add the ordered validator to the topic
if not w.validatorInserted.hasKey(pubSubTopic):
procCall GossipSub(w).addValidator(pubSubTopic, w.generateOrderedValidator())
w.validatorInserted[pubSubTopic] = true
# set this topic parameters for scoring
w.topicParams[pubsubTopic] = TopicParameters
# subscribe to the topic with our wrapped handler
procCall GossipSub(w).subscribe(pubsubTopic, wrappedHandler)
return wrappedHandler
proc unsubscribeAll*(w: WakuRelay, pubsubTopic: PubsubTopic) =
## Unsubscribe all handlers on this pubsub topic
debug "unsubscribe all", pubsubTopic=pubsubTopic
procCall GossipSub(w).unsubscribeAll(pubsubTopic)
w.validatorInserted.del(pubsubTopic)
proc unsubscribe*(w: WakuRelay, pubsubTopic: PubsubTopic, handler: TopicHandler) =
## Unsubscribe this handler on this pubsub topic
debug "unsubscribe", pubsubTopic=pubsubTopic
procCall GossipSub(w).unsubscribe(pubsubTopic, handler)
proc publish*(w: WakuRelay, pubsubTopic: PubsubTopic, message: WakuMessage): Future[int] {.async.} =
trace "publish", pubsubTopic=pubsubTopic
let data = message.encode().buffer
return await procCall GossipSub(w).publish(pubsubTopic, data)