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nim-eth/eth/p2p/rlpx_protocols/whisper_protocol.nim

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#
# Whisper
# (c) Copyright 2018-2019
# Status Research & Development GmbH
#
# Licensed under either of
# Apache License, version 2.0, (LICENSE-APACHEv2)
# MIT license (LICENSE-MIT)
#
## Whisper
## *******
##
## Whisper is a gossip protocol that synchronizes a set of messages across nodes
## with attention given to sender and recipient anonymitiy. Messages are
## categorized by a topic and stay alive in the network based on a time-to-live
## measured in seconds. Spam prevention is based on proof-of-work, where large
## or long-lived messages must spend more work.
##
## Example usage
## ----------
## First an `EthereumNode` needs to be created, either with all capabilities set
## or with specifically the Whisper capability set.
## The latter can be done like this:
##
## .. code-block::nim
## var node = newEthereumNode(keypair, address, netId, nil,
## addAllCapabilities = false)
## node.addCapability Whisper
##
## Now calls such as ``postMessage`` and ``subscribeFilter`` can be done.
## However, they only make real sense after ``connectToNetwork`` was started. As
## else there will be no peers to send and receive messages from.
import
options, tables, times, chronos, chronicles, metrics,
eth/[keys, async_utils, p2p], whisper/whisper_types
export
whisper_types
logScope:
topics = "whisper"
declareCounter valid_envelopes,
"Received & posted valid envelopes"
declareCounter dropped_low_pow_envelopes,
"Dropped envelopes because of too low PoW"
declareCounter dropped_too_large_envelopes,
"Dropped envelopes because larger than maximum allowed size"
declareCounter dropped_bloom_filter_mismatch_envelopes,
"Dropped envelopes because not matching with bloom filter"
declareCounter dropped_benign_duplicate_envelopes,
"Dropped benign duplicate envelopes"
declareCounter dropped_malicious_duplicate_envelopes,
"Dropped malicious duplicate envelopes"
const
defaultQueueCapacity = 256
whisperVersion* = 6 ## Whisper version.
whisperVersionStr* = $whisperVersion ## Whisper version.
defaultMinPow* = 0.2'f64 ## The default minimum PoW requirement for this node.
defaultMaxMsgSize* = 1024'u32 * 1024'u32 ## The current default and max
## message size. This can never be larger than the maximum RLPx message size.
messageInterval* = chronos.milliseconds(300) ## Interval at which messages are
## send to peers, in ms.
pruneInterval* = chronos.milliseconds(1000) ## Interval at which message
## queue is pruned, in ms.
type
WhisperConfig* = object
powRequirement*: float64
bloom*: Bloom
isLightNode*: bool
maxMsgSize*: uint32
WhisperPeer = ref object
initialized: bool # when successfully completed the handshake
powRequirement*: float64
bloom*: Bloom
isLightNode*: bool
trusted*: bool
received: HashSet[Message]
WhisperNetwork = ref object
queue*: ref Queue
filters*: Filters
config*: WhisperConfig
proc allowed*(msg: Message, config: WhisperConfig): bool =
# Check max msg size, already happens in RLPx but there is a specific shh
# max msg size which should always be < RLPx max msg size
if msg.size > config.maxMsgSize:
dropped_too_large_envelopes.inc()
warn "Message size too large", size = msg.size
return false
if msg.pow < config.powRequirement:
dropped_low_pow_envelopes.inc()
warn "Message PoW too low", pow = msg.pow, minPow = config.powRequirement
return false
if not bloomFilterMatch(config.bloom, msg.bloom):
dropped_bloom_filter_mismatch_envelopes.inc()
warn "Message does not match node bloom filter"
return false
return true
proc run(peer: Peer) {.gcsafe, async.}
proc run(node: EthereumNode, network: WhisperNetwork) {.gcsafe, async.}
proc initProtocolState*(network: WhisperNetwork, node: EthereumNode) {.gcsafe.} =
new(network.queue)
network.queue[] = initQueue(defaultQueueCapacity)
network.filters = initTable[string, Filter]()
network.config.bloom = fullBloom()
network.config.powRequirement = defaultMinPow
network.config.isLightNode = false
network.config.maxMsgSize = defaultMaxMsgSize
asyncCheck node.run(network)
p2pProtocol Whisper(version = whisperVersion,
rlpxName = "shh",
peerState = WhisperPeer,
networkState = WhisperNetwork):
onPeerConnected do (peer: Peer):
trace "onPeerConnected Whisper"
let
whisperNet = peer.networkState
whisperPeer = peer.state
let m = await peer.status(whisperVersion,
cast[uint64](whisperNet.config.powRequirement),
@(whisperNet.config.bloom),
whisperNet.config.isLightNode,
timeout = chronos.milliseconds(500))
if m.protocolVersion == whisperVersion:
debug "Whisper peer", peer, whisperVersion
else:
raise newException(UselessPeerError, "Incompatible Whisper version")
whisperPeer.powRequirement = cast[float64](m.powConverted)
if m.bloom.len > 0:
if m.bloom.len != bloomSize:
raise newException(UselessPeerError, "Bloomfilter size mismatch")
else:
whisperPeer.bloom.bytesCopy(m.bloom)
else:
# If no bloom filter is send we allow all
whisperPeer.bloom = fullBloom()
whisperPeer.isLightNode = m.isLightNode
if whisperPeer.isLightNode and whisperNet.config.isLightNode:
# No sense in connecting two light nodes so we disconnect
raise newException(UselessPeerError, "Two light nodes connected")
whisperPeer.received.init()
whisperPeer.trusted = false
whisperPeer.initialized = true
if not whisperNet.config.isLightNode:
traceAsyncErrors peer.run()
debug "Whisper peer initialized", peer
handshake:
proc status(peer: Peer,
protocolVersion: uint,
powConverted: uint64,
bloom: Bytes,
isLightNode: bool)
proc messages(peer: Peer, envelopes: openarray[Envelope]) =
if not peer.state.initialized:
warn "Handshake not completed yet, discarding messages"
return
for envelope in envelopes:
# check if expired or in future, or ttl not 0
if not envelope.valid():
warn "Expired or future timed envelope", peer
# disconnect from peers sending bad envelopes
# await peer.disconnect(SubprotocolReason)
continue
let msg = initMessage(envelope)
if not msg.allowed(peer.networkState.config):
# disconnect from peers sending bad envelopes
# await peer.disconnect(SubprotocolReason)
continue
# This peer send this message thus should not receive it again.
# If this peer has the message in the `received` set already, this means
# it was either already received here from this peer or send to this peer.
# Either way it will be in our queue already (and the peer should know
# this) and this peer is sending duplicates.
# Note: geth does not check if a peer has send a message to them before
# broadcasting this message. This too is seen here as a duplicate message
# (see above comment). If we want to seperate these cases (e.g. when peer
# rating), then we have to add a "peer.state.send" HashSet.
if peer.state.received.containsOrIncl(msg):
dropped_malicious_duplicate_envelopes.inc()
debug "Peer sending duplicate messages", peer, hash = msg.hash
# await peer.disconnect(SubprotocolReason)
continue
# This can still be a duplicate message, but from another peer than
# the peer who send the message.
if peer.networkState.queue[].add(msg):
valid_envelopes.inc()
# notify filters of this message
peer.networkState.filters.notify(msg)
else:
dropped_benign_duplicate_envelopes.inc()
proc powRequirement(peer: Peer, value: uint64) =
if not peer.state.initialized:
warn "Handshake not completed yet, discarding powRequirement"
return
peer.state.powRequirement = cast[float64](value)
proc bloomFilterExchange(peer: Peer, bloom: Bytes) =
if not peer.state.initialized:
warn "Handshake not completed yet, discarding bloomFilterExchange"
return
if bloom.len == bloomSize:
peer.state.bloom.bytesCopy(bloom)
nextID 126
proc p2pRequest(peer: Peer, envelope: Envelope) =
# TODO: here we would have to allow to insert some specific implementation
# such as e.g. Whisper Mail Server
discard
proc p2pMessage(peer: Peer, envelope: Envelope) =
if peer.state.trusted:
# when trusted we can bypass any checks on envelope
let msg = Message(env: envelope, isP2P: true)
peer.networkState.filters.notify(msg)
# Following message IDs are not part of EIP-627, but are added and used by
# the Status application, we ignore them for now.
nextID 11
proc batchAcknowledged(peer: Peer) = discard
proc messageResponse(peer: Peer) = discard
nextID 123
requestResponse:
proc p2pSyncRequest(peer: Peer) = discard
proc p2pSyncResponse(peer: Peer) = discard
proc p2pRequestComplete(peer: Peer) = discard
# 'Runner' calls ---------------------------------------------------------------
proc processQueue(peer: Peer) =
# Send to peer all valid and previously not send envelopes in the queue.
var
envelopes: seq[Envelope] = @[]
whisperPeer = peer.state(Whisper)
whisperNet = peer.networkState(Whisper)
for message in whisperNet.queue.items:
if whisperPeer.received.contains(message):
# debug "message was already send to peer"
continue
if message.pow < whisperPeer.powRequirement:
debug "Message PoW too low for peer", pow = message.pow,
powReq = whisperPeer.powRequirement
continue
if not bloomFilterMatch(whisperPeer.bloom, message.bloom):
debug "Message does not match peer bloom filter"
continue
trace "Adding envelope"
envelopes.add(message.env)
whisperPeer.received.incl(message)
if envelopes.len() > 0:
trace "Sending envelopes", amount=envelopes.len
# Ignore failure of sending messages, this could occur when the connection
# gets dropped
traceAsyncErrors peer.messages(envelopes)
proc run(peer: Peer) {.async.} =
while peer.connectionState notin {Disconnecting, Disconnected}:
peer.processQueue()
await sleepAsync(messageInterval)
proc pruneReceived(node: EthereumNode) {.raises: [].} =
if node.peerPool != nil: # XXX: a bit dirty to need to check for this here ...
var whisperNet = node.protocolState(Whisper)
for peer in node.protocolPeers(Whisper):
if not peer.initialized:
continue
# NOTE: Perhaps alter the queue prune call to keep track of a HashSet
# of pruned messages (as these should be smaller), and diff this with
# the received sets.
peer.received = intersection(peer.received, whisperNet.queue.itemHashes)
proc run(node: EthereumNode, network: WhisperNetwork) {.async.} =
while true:
# prune message queue every second
# TTL unit is in seconds, so this should be sufficient?
network.queue[].prune()
# pruning the received sets is not necessary for correct workings
# but simply from keeping the sets growing indefinitely
node.pruneReceived()
await sleepAsync(pruneInterval)
# Private EthereumNode calls ---------------------------------------------------
proc sendP2PMessage(node: EthereumNode, peerId: NodeId, env: Envelope): bool =
for peer in node.peers(Whisper):
if peer.remote.id == peerId:
asyncCheck peer.p2pMessage(env)
return true
proc queueMessage(node: EthereumNode, msg: Message): bool =
var whisperNet = node.protocolState(Whisper)
# We have to do the same checks here as in the messages proc not to leak
# any information that the message originates from this node.
if not msg.allowed(whisperNet.config):
return false
trace "Adding message to queue"
if whisperNet.queue[].add(msg):
valid_envelopes.inc()
# Also notify our own filters of the message we are sending,
# e.g. msg from local Dapp to Dapp
whisperNet.filters.notify(msg)
return true
# Public EthereumNode calls ----------------------------------------------------
proc postMessage*(node: EthereumNode, pubKey = none[PublicKey](),
symKey = none[SymKey](), src = none[PrivateKey](),
ttl: uint32, topic: Topic, payload: Bytes,
padding = none[Bytes](), powTime = 1'f,
powTarget = defaultMinPow,
targetPeer = none[NodeId]()): bool =
## Post a message on the message queue which will be processed at the
## next `messageInterval`.
##
## NOTE: This call allows a post without encryption. If encryption is
## mandatory it should be enforced a layer up
let payload = encode(Payload(payload: payload, src: src, dst: pubKey,
symKey: symKey, padding: padding))
if payload.isSome():
var env = Envelope(expiry:epochTime().uint32 + ttl,
ttl: ttl, topic: topic, data: payload.get(), nonce: 0)
# Allow lightnode to post only direct p2p messages
if targetPeer.isSome():
return node.sendP2PMessage(targetPeer.get(), env)
elif not node.protocolState(Whisper).config.isLightNode:
# non direct p2p message can not have ttl of 0
if env.ttl == 0:
return false
var msg = initMessage(env, powCalc = false)
# XXX: make this non blocking or not?
# In its current blocking state, it could be noticed by a peer that no
# messages are send for a while, and thus that mining PoW is done, and
# that next messages contains a message originated from this peer
# zah: It would be hard to execute this in a background thread at the
# moment. We'll need a way to send custom "tasks" to the async message
# loop (e.g. AD2 support for AsyncChannels).
if not msg.sealEnvelope(powTime, powTarget):
return false
# need to check expiry after mining PoW
if not msg.env.valid():
return false
return node.queueMessage(msg)
else:
warn "Light node not allowed to post messages"
return false
else:
error "Encoding of payload failed"
return false
proc subscribeFilter*(node: EthereumNode, filter: Filter,
handler:FilterMsgHandler = nil): string =
## Initiate a filter for incoming/outgoing messages. Messages can be
## retrieved with the `getFilterMessages` call or with a provided
## `FilterMsgHandler`.
##
## NOTE: This call allows for a filter without decryption. If encryption is
## mandatory it should be enforced a layer up.
return node.protocolState(Whisper).filters.subscribeFilter(filter, handler)
proc unsubscribeFilter*(node: EthereumNode, filterId: string): bool =
## Remove a previously subscribed filter.
var filter: Filter
return node.protocolState(Whisper).filters.take(filterId, filter)
proc getFilterMessages*(node: EthereumNode, filterId: string): seq[ReceivedMessage] =
## Get all the messages currently in the filter queue. This will reset the
## filter message queue.
return node.protocolState(Whisper).filters.getFilterMessages(filterId)
proc filtersToBloom*(node: EthereumNode): Bloom =
## Returns the bloom filter of all topics of all subscribed filters.
return node.protocolState(Whisper).filters.toBloom()
proc setPowRequirement*(node: EthereumNode, powReq: float64) {.async.} =
## Sets the PoW requirement for this node, will also send
## this new PoW requirement to all connected peers.
##
## Failures when sending messages to peers will not be reported.
# NOTE: do we need a tolerance of old PoW for some time?
node.protocolState(Whisper).config.powRequirement = powReq
var futures: seq[Future[void]] = @[]
for peer in node.peers(Whisper):
futures.add(peer.powRequirement(cast[uint64](powReq)))
# Exceptions from sendMsg will not be raised
await allFutures(futures)
proc setBloomFilter*(node: EthereumNode, bloom: Bloom) {.async.} =
## Sets the bloom filter for this node, will also send
## this new bloom filter to all connected peers.
##
## Failures when sending messages to peers will not be reported.
# NOTE: do we need a tolerance of old bloom filter for some time?
node.protocolState(Whisper).config.bloom = bloom
var futures: seq[Future[void]] = @[]
for peer in node.peers(Whisper):
futures.add(peer.bloomFilterExchange(@bloom))
# Exceptions from sendMsg will not be raised
await allFutures(futures)
proc setMaxMessageSize*(node: EthereumNode, size: uint32): bool =
## Set the maximum allowed message size.
## Can not be set higher than ``defaultMaxMsgSize``.
if size > defaultMaxMsgSize:
warn "size > defaultMaxMsgSize"
return false
node.protocolState(Whisper).config.maxMsgSize = size
return true
proc setPeerTrusted*(node: EthereumNode, peerId: NodeId): bool =
## Set a connected peer as trusted.
for peer in node.peers(Whisper):
if peer.remote.id == peerId:
peer.state(Whisper).trusted = true
return true
proc setLightNode*(node: EthereumNode, isLightNode: bool) =
## Set this node as a Whisper light node.
##
## NOTE: Should be run before connection is made with peers as this
## setting is only communicated at peer handshake.
node.protocolState(Whisper).config.isLightNode = isLightNode
proc configureWhisper*(node: EthereumNode, config: WhisperConfig) =
## Apply a Whisper configuration.
##
## NOTE: Should be run before connection is made with peers as some
## of the settings are only communicated at peer handshake.
node.protocolState(Whisper).config = config
proc resetMessageQueue*(node: EthereumNode) =
## Full reset of the message queue.
##
## NOTE: Not something that should be run in normal circumstances.
node.protocolState(Whisper).queue[] = initQueue(defaultQueueCapacity)
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