nwaku/waku/waku_rln_relay/rln_relay.nim

401 lines
16 KiB
Nim

when (NimMajor, NimMinor) < (1, 4):
{.push raises: [Defect].}
else:
{.push raises: [].}
import
std/[algorithm, sequtils, strutils, tables, times, os, deques],
chronicles, options, chronos, chronos/ratelimit, stint,
confutils,
web3, json,
web3/ethtypes,
eth/keys,
libp2p/protocols/pubsub/rpc/messages,
libp2p/protocols/pubsub/pubsub,
stew/results,
stew/[byteutils, arrayops]
import
./group_manager,
./rln,
./conversion_utils,
./constants,
./protocol_types,
./protocol_metrics
import
../waku_core,
../waku_keystore,
../utils/collector
logScope:
topics = "waku rln_relay"
type WakuRlnConfig* = object
rlnRelayDynamic*: bool
rlnRelayCredIndex*: uint
rlnRelayEthContractAddress*: string
rlnRelayEthClientAddress*: string
rlnRelayCredPath*: string
rlnRelayCredPassword*: string
rlnRelayTreePath*: string
rlnRelayBandwidthThreshold*: int
proc createMembershipList*(rln: ptr RLN, n: int): RlnRelayResult[(
seq[RawMembershipCredentials], string
)] =
## createMembershipList produces a sequence of identity credentials in the form of (identity trapdoor, identity nullifier, identity secret hash, id commitment) in the hexadecimal format
## this proc also returns the root of a Merkle tree constructed out of the identity commitment keys of the generated list
## the output of this proc is used to initialize a static group keys (to test waku-rln-relay in the off-chain mode)
## Returns an error if it cannot create the membership list
var output = newSeq[RawMembershipCredentials]()
var idCommitments = newSeq[IDCommitment]()
for i in 0..n-1:
# generate an identity credential
let idCredentialRes = rln.membershipKeyGen()
if idCredentialRes.isErr():
return err("could not generate an identity credential: " & idCredentialRes.error())
let idCredential = idCredentialRes.get()
let idTuple = (idCredential.idTrapdoor.inHex(), idCredential.idNullifier.inHex(), idCredential.idSecretHash.inHex(), idCredential.idCommitment.inHex())
output.add(idTuple)
idCommitments.add(idCredential.idCommitment)
# Insert members into tree
let membersAdded = rln.insertMembers(0, idCommitments)
if not membersAdded:
return err("could not insert members into the tree")
let root = rln.getMerkleRoot().value().inHex()
return ok((output, root))
proc calcEpoch*(t: float64): Epoch =
## gets time `t` as `flaot64` with subseconds resolution in the fractional part
## and returns its corresponding rln `Epoch` value
let e = uint64(t/EpochUnitSeconds)
return toEpoch(e)
type WakuRLNRelay* = ref object of RootObj
# the log of nullifiers and Shamir shares of the past messages grouped per epoch
nullifierLog*: Table[Epoch, seq[ProofMetadata]]
lastEpoch*: Epoch # the epoch of the last published rln message
groupManager*: GroupManager
messageBucket*: Option[TokenBucket]
method stop*(rlnPeer: WakuRLNRelay) {.async.} =
## stops the rln-relay protocol
## Throws an error if it cannot stop the rln-relay protocol
# stop the group sync, and flush data to tree db
info "stopping rln-relay"
await rlnPeer.groupManager.stop()
proc hasDuplicate*(rlnPeer: WakuRLNRelay,
proofMetadata: ProofMetadata): RlnRelayResult[bool] =
## returns true if there is another message in the `nullifierLog` of the `rlnPeer` with the same
## epoch and nullifier as `proofMetadata`'s epoch and nullifier
## otherwise, returns false
## Returns an error if it cannot check for duplicates
let externalNullifier = proofMetadata.externalNullifier
# check if the epoch exists
if not rlnPeer.nullifierLog.hasKey(externalNullifier):
return ok(false)
try:
if rlnPeer.nullifierLog[externalNullifier].contains(proofMetadata):
# there is an identical record, mark it as spam
return ok(true)
# check for a message with the same nullifier but different secret shares
let matched = rlnPeer.nullifierLog[externalNullifier].filterIt((
it.nullifier == proofMetadata.nullifier) and ((it.shareX != proofMetadata.shareX) or
(it.shareY != proofMetadata.shareY)))
if matched.len != 0:
# there is a duplicate
return ok(true)
# there is no duplicate
return ok(false)
except KeyError as e:
return err("the epoch was not found")
proc updateLog*(rlnPeer: WakuRLNRelay,
proofMetadata: ProofMetadata): RlnRelayResult[void] =
## saves supplied proofMetadata `proofMetadata`
## in the `nullifierLog` of the `rlnPeer`
## Returns an error if it cannot update the log
let externalNullifier = proofMetadata.externalNullifier
# check if the externalNullifier exists
if not rlnPeer.nullifierLog.hasKey(externalNullifier):
rlnPeer.nullifierLog[externalNullifier] = @[proofMetadata]
return ok()
try:
# check if an identical record exists
if rlnPeer.nullifierLog[externalNullifier].contains(proofMetadata):
# TODO: slashing logic
return ok()
# add proofMetadata to the log
rlnPeer.nullifierLog[externalNullifier].add(proofMetadata)
return ok()
except KeyError as e:
return err("the external nullifier was not found") # should never happen
proc getCurrentEpoch*(): Epoch =
## gets the current rln Epoch time
return calcEpoch(epochTime())
proc absDiff*(e1, e2: Epoch): uint64 =
## returns the absolute difference between the two rln `Epoch`s `e1` and `e2`
## i.e., e1 - e2
# convert epochs to their corresponding unsigned numerical values
let
epoch1 = fromEpoch(e1)
epoch2 = fromEpoch(e2)
# Manually perform an `abs` calculation
if epoch1 > epoch2:
return epoch1 - epoch2
else:
return epoch2 - epoch1
proc validateMessage*(rlnPeer: WakuRLNRelay,
msg: WakuMessage,
timeOption = none(float64)): MessageValidationResult =
## validate the supplied `msg` based on the waku-rln-relay routing protocol i.e.,
## the `msg`'s epoch is within MaxEpochGap of the current epoch
## the `msg` has valid rate limit proof
## the `msg` does not violate the rate limit
## `timeOption` indicates Unix epoch time (fractional part holds sub-seconds)
## if `timeOption` is supplied, then the current epoch is calculated based on that
let decodeRes = RateLimitProof.init(msg.proof)
if decodeRes.isErr():
return MessageValidationResult.Invalid
let proof = decodeRes.get()
# track message count for metrics
waku_rln_messages_total.inc()
# checks if the `msg`'s epoch is far from the current epoch
# it corresponds to the validation of rln external nullifier
var epoch: Epoch
if timeOption.isSome():
epoch = calcEpoch(timeOption.get())
else:
# get current rln epoch
epoch = getCurrentEpoch()
debug "current epoch", currentEpoch = fromEpoch(epoch)
let
msgEpoch = proof.epoch
# calculate the gaps
gap = absDiff(epoch, msgEpoch)
debug "message epoch", msgEpoch = fromEpoch(msgEpoch)
# validate the epoch
if gap > MaxEpochGap:
# message's epoch is too old or too ahead
# accept messages whose epoch is within +-MaxEpochGap from the current epoch
warn "invalid message: epoch gap exceeds a threshold", gap = gap,
payload = string.fromBytes(msg.payload), msgEpoch = fromEpoch(proof.epoch)
waku_rln_invalid_messages_total.inc(labelValues=["invalid_epoch"])
return MessageValidationResult.Invalid
let rootValidationRes = rlnPeer.groupManager.validateRoot(proof.merkleRoot)
if not rootValidationRes:
debug "invalid message: provided root does not belong to acceptable window of roots", provided=proof.merkleRoot.inHex(), validRoots=rlnPeer.groupManager.validRoots.mapIt(it.inHex())
waku_rln_invalid_messages_total.inc(labelValues=["invalid_root"])
return MessageValidationResult.Invalid
# verify the proof
let
contentTopicBytes = msg.contentTopic.toBytes
input = concat(msg.payload, contentTopicBytes)
waku_rln_proof_verification_total.inc()
waku_rln_proof_verification_duration_seconds.nanosecondTime:
let proofVerificationRes = rlnPeer.groupManager.verifyProof(input, proof)
if proofVerificationRes.isErr():
waku_rln_errors_total.inc(labelValues=["proof_verification"])
warn "invalid message: proof verification failed", payload = string.fromBytes(msg.payload)
return MessageValidationResult.Invalid
if not proofVerificationRes.value():
# invalid proof
debug "invalid message: invalid proof", payload = string.fromBytes(msg.payload)
waku_rln_invalid_messages_total.inc(labelValues=["invalid_proof"])
return MessageValidationResult.Invalid
# check if double messaging has happened
let proofMetadataRes = proof.extractMetadata()
if proofMetadataRes.isErr():
waku_rln_errors_total.inc(labelValues=["proof_metadata_extraction"])
return MessageValidationResult.Invalid
let hasDup = rlnPeer.hasDuplicate(proofMetadataRes.get())
if hasDup.isErr():
waku_rln_errors_total.inc(labelValues=["duplicate_check"])
elif hasDup.value == true:
debug "invalid message: message is spam", payload = string.fromBytes(msg.payload)
waku_rln_spam_messages_total.inc()
return MessageValidationResult.Spam
# insert the message to the log
# the result of `updateLog` is discarded because message insertion is guaranteed by the implementation i.e.,
# it will never error out
discard rlnPeer.updateLog(proofMetadataRes.get())
debug "message is valid", payload = string.fromBytes(msg.payload)
let rootIndex = rlnPeer.groupManager.indexOfRoot(proof.merkleRoot)
waku_rln_valid_messages_total.observe(rootIndex.toFloat())
return MessageValidationResult.Valid
proc toRLNSignal*(wakumessage: WakuMessage): seq[byte] =
## it is a utility proc that prepares the `data` parameter of the proof generation procedure i.e., `proofGen` that resides in the current module
## it extracts the `contentTopic` and the `payload` of the supplied `wakumessage` and serializes them into a byte sequence
let
contentTopicBytes = wakumessage.contentTopic.toBytes()
output = concat(wakumessage.payload, contentTopicBytes)
return output
proc appendRLNProof*(rlnPeer: WakuRLNRelay,
msg: var WakuMessage,
senderEpochTime: float64): bool =
## returns true if it can create and append a `RateLimitProof` to the supplied `msg`
## returns false otherwise
## `senderEpochTime` indicates the number of seconds passed since Unix epoch. The fractional part holds sub-seconds.
## The `epoch` field of `RateLimitProof` is derived from the provided `senderEpochTime` (using `calcEpoch()`)
let input = msg.toRLNSignal()
let epoch = calcEpoch(senderEpochTime)
let proofGenRes = rlnPeer.groupManager.generateProof(input, epoch)
if proofGenRes.isErr():
return false
msg.proof = proofGenRes.get().encode().buffer
return true
proc generateRlnValidator*(wakuRlnRelay: WakuRLNRelay,
spamHandler: Option[SpamHandler] = none(SpamHandler)): pubsub.ValidatorHandler =
## this procedure is a thin wrapper for the pubsub addValidator method
## it sets a validator for waku messages, acting in the registered pubsub topic
## the message validation logic is according to https://rfc.vac.dev/spec/17/
proc validator(topic: string, message: messages.Message): Future[pubsub.ValidationResult] {.async.} =
trace "rln-relay topic validator is called"
## Check if enough tokens can be consumed from the message bucket
try:
if wakuRlnRelay.messageBucket.isSome() and
wakuRlnRelay.messageBucket.get().tryConsume(message.data.len):
return pubsub.ValidationResult.Accept
else:
info "message bandwidth limit exceeded, running rate limit proof validation"
except OverflowDefect: # not a problem
debug "not enough bandwidth, running rate limit proof validation"
let decodeRes = WakuMessage.decode(message.data)
if decodeRes.isOk():
let wakumessage = decodeRes.value
let decodeRes = RateLimitProof.init(wakumessage.proof)
if decodeRes.isErr():
return pubsub.ValidationResult.Reject
let msgProof = decodeRes.get()
# validate the message
let
validationRes = wakuRlnRelay.validateMessage(wakumessage)
proof = toHex(msgProof.proof)
epoch = fromEpoch(msgProof.epoch)
root = inHex(msgProof.merkleRoot)
shareX = inHex(msgProof.shareX)
shareY = inHex(msgProof.shareY)
nullifier = inHex(msgProof.nullifier)
payload = string.fromBytes(wakumessage.payload)
case validationRes:
of Valid:
debug "message validity is verified, relaying:", contentTopic=wakumessage.contentTopic, epoch=epoch, timestamp=wakumessage.timestamp, payload=payload
trace "message validity is verified, relaying:", proof=proof, root=root, shareX=shareX, shareY=shareY, nullifier=nullifier
return pubsub.ValidationResult.Accept
of Invalid:
debug "message validity could not be verified, discarding:", contentTopic=wakumessage.contentTopic, epoch=epoch, timestamp=wakumessage.timestamp, payload=payload
trace "message validity could not be verified, discarding:", proof=proof, root=root, shareX=shareX, shareY=shareY, nullifier=nullifier
return pubsub.ValidationResult.Reject
of Spam:
debug "A spam message is found! yay! discarding:", contentTopic=wakumessage.contentTopic, epoch=epoch, timestamp=wakumessage.timestamp, payload=payload
trace "A spam message is found! yay! discarding:", proof=proof, root=root, shareX=shareX, shareY=shareY, nullifier=nullifier
if spamHandler.isSome():
let handler = spamHandler.get()
handler(wakumessage)
return pubsub.ValidationResult.Reject
return validator
proc mount(conf: WakuRlnConfig,
registrationHandler: Option[RegistrationHandler] = none(RegistrationHandler)
): Future[WakuRlnRelay] {.async.} =
var
groupManager: GroupManager
# create an RLN instance
let rlnInstanceRes = createRLNInstance(tree_path = conf.rlnRelayTreePath)
if rlnInstanceRes.isErr():
raise newException(CatchableError, "RLN instance creation failed")
let rlnInstance = rlnInstanceRes.get()
if not conf.rlnRelayDynamic:
# static setup
let parsedGroupKeysRes = StaticGroupKeys.toIdentityCredentials()
if parsedGroupKeysRes.isErr():
raise newException(ValueError, "Static group keys are not valid")
groupManager = StaticGroupManager(groupSize: StaticGroupSize,
groupKeys: parsedGroupKeysRes.get(),
membershipIndex: some(conf.rlnRelayCredIndex),
rlnInstance: rlnInstance)
# we don't persist credentials in static mode since they exist in ./constants.nim
else:
# dynamic setup
proc useValueOrNone(s: string): Option[string] =
if s == "": none(string) else: some(s)
let
rlnRelayCredPath = useValueOrNone(conf.rlnRelayCredPath)
rlnRelayCredPassword = useValueOrNone(conf.rlnRelayCredPassword)
groupManager = OnchainGroupManager(ethClientUrl: conf.rlnRelayEthClientAddress,
ethContractAddress: $conf.rlnRelayEthContractAddress,
rlnInstance: rlnInstance,
registrationHandler: registrationHandler,
keystorePath: rlnRelayCredPath,
keystorePassword: rlnRelayCredPassword,
membershipIndex: some(conf.rlnRelayCredIndex))
# Initialize the groupManager
await groupManager.init()
# Start the group sync
await groupManager.startGroupSync()
let messageBucket = if conf.rlnRelayBandwidthThreshold > 0:
some(TokenBucket.new(conf.rlnRelayBandwidthThreshold))
else: none(TokenBucket)
return WakuRLNRelay(groupManager: groupManager,
messageBucket: messageBucket)
proc new*(T: type WakuRlnRelay,
conf: WakuRlnConfig,
registrationHandler: Option[RegistrationHandler] = none(RegistrationHandler)
): Future[RlnRelayResult[WakuRlnRelay]] {.async.} =
## Mounts the rln-relay protocol on the node.
## The rln-relay protocol can be mounted in two modes: on-chain and off-chain.
## Returns an error if the rln-relay protocol could not be mounted.
debug "rln-relay input validation passed"
try:
let rlnRelay = await mount(conf, registrationHandler)
return ok(rlnRelay)
except CatchableError as e:
return err(e.msg)