nim-libp2p-experimental/libp2p/protocols/pubsub/gossipsub.nim

1362 lines
47 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2019 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import std/[tables, sets, options, sequtils, random, algorithm]
import chronos, chronicles, metrics
import ./pubsub,
./floodsub,
./pubsubpeer,
./peertable,
./mcache,
./timedcache,
./rpc/[messages, message],
../protocol,
../../stream/connection,
../../peerinfo,
../../peerid,
../../utility
import stew/results
export results
logScope:
topics = "gossipsub"
const
GossipSubCodec* = "/meshsub/1.1.0"
GossipSubCodec_10* = "/meshsub/1.0.0"
# overlay parameters
const
GossipSubD* = 6
GossipSubDlo* = 4
GossipSubDhi* = 12
# gossip parameters
const
GossipSubHistoryLength* = 5
GossipSubHistoryGossip* = 3
# heartbeat interval
GossipSubHeartbeatInterval* = 1.seconds
# fanout ttl
const
GossipSubFanoutTTL* = 1.minutes
# gossip parameters
const
GossipBackoffPeriod* = 1.minutes
const
BackoffSlackTime = 2 # seconds
IWantPeerBudget = 25 # 25 messages per second ( reset every heartbeat )
IHavePeerBudget = 10
type
TopicInfo* = object
# gossip 1.1 related
graftTime: Moment
meshTime: Duration
inMesh: bool
meshMessageDeliveriesActive: bool
firstMessageDeliveries: float64
meshMessageDeliveries: float64
meshFailurePenalty: float64
invalidMessageDeliveries: float64
TopicParams* = object
topicWeight*: float64
# p1
timeInMeshWeight*: float64
timeInMeshQuantum*: Duration
timeInMeshCap*: float64
# p2
firstMessageDeliveriesWeight*: float64
firstMessageDeliveriesDecay*: float64
firstMessageDeliveriesCap*: float64
# p3
meshMessageDeliveriesWeight*: float64
meshMessageDeliveriesDecay*: float64
meshMessageDeliveriesThreshold*: float64
meshMessageDeliveriesCap*: float64
meshMessageDeliveriesActivation*: Duration
meshMessageDeliveriesWindow*: Duration
# p3b
meshFailurePenaltyWeight*: float64
meshFailurePenaltyDecay*: float64
# p4
invalidMessageDeliveriesWeight*: float64
invalidMessageDeliveriesDecay*: float64
PeerStats* = object
topicInfos*: Table[string, TopicInfo]
expire*: Moment # updated on disconnect, to retain scores until expire
GossipSubParams* = object
explicit: bool
pruneBackoff*: Duration
floodPublish*: bool
gossipFactor*: float64
d*: int
dLow*: int
dHigh*: int
dScore*: int
dOut*: int
dLazy*: int
heartbeatInterval*: Duration
historyLength*: int
historyGossip*: int
fanoutTTL*: Duration
gossipThreshold*: float64
publishThreshold*: float64
graylistThreshold*: float64
acceptPXThreshold*: float64
opportunisticGraftThreshold*: float64
decayInterval*: Duration
decayToZero*: float64
retainScore*: Duration
appSpecificWeight*: float64
ipColocationFactorWeight*: float64
ipColocationFactorThreshold*: float64
behaviourPenaltyWeight*: float64
behaviourPenaltyDecay*: float64
directPeers*: seq[PeerId]
GossipSub* = ref object of FloodSub
mesh*: PeerTable # peers that we send messages to when we are subscribed to the topic
fanout*: PeerTable # peers that we send messages to when we're not subscribed to the topic
gossipsub*: PeerTable # peers that are subscribed to a topic
explicit*: PeerTable # directpeers that we keep alive explicitly
backingOff*: Table[PeerID, Moment] # explicit (always connected/forward) peers
lastFanoutPubSub*: Table[string, Moment] # last publish time for fanout topics
gossip*: Table[string, seq[ControlIHave]] # pending gossip
control*: Table[string, ControlMessage] # pending control messages
mcache*: MCache # messages cache
heartbeatFut: Future[void] # cancellation future for heartbeat interval
heartbeatRunning: bool
peerStats: Table[PubSubPeer, PeerStats]
parameters*: GossipSubParams
topicParams*: Table[string, TopicParams]
directPeersLoop: Future[void]
peersInIP: Table[MultiAddress, HashSet[PubSubPeer]]
heartbeatEvents*: seq[AsyncEvent]
when not defined(release):
prunedPeers: HashSet[PubSubPeer]
when defined(libp2p_expensive_metrics):
declareGauge(libp2p_gossipsub_peers_per_topic_mesh,
"gossipsub peers per topic in mesh",
labels = ["topic"])
declareGauge(libp2p_gossipsub_peers_per_topic_fanout,
"gossipsub peers per topic in fanout",
labels = ["topic"])
declareGauge(libp2p_gossipsub_peers_per_topic_gossipsub,
"gossipsub peers per topic in gossipsub",
labels = ["topic"])
declareGauge(libp2p_gossipsub_peers_mesh_sum, "pubsub peers in mesh table summed")
declareGauge(libp2p_gossipsub_peers_gossipsub_sum, "pubsub peers in gossipsub table summed")
proc init*(_: type[GossipSubParams]): GossipSubParams =
GossipSubParams(
explicit: true,
pruneBackoff: 1.minutes,
floodPublish: true,
gossipFactor: 0.25,
d: GossipSubD,
dLow: GossipSubDlo,
dHigh: GossipSubDhi,
dScore: GossipSubDlo,
dOut: GossipSubDlo - 1, # DLow - 1
dLazy: GossipSubD, # Like D
heartbeatInterval: GossipSubHeartbeatInterval,
historyLength: GossipSubHistoryLength,
historyGossip: GossipSubHistoryGossip,
fanoutTTL: GossipSubFanoutTTL,
gossipThreshold: -10,
publishThreshold: -100,
graylistThreshold: -10000,
opportunisticGraftThreshold: 0,
decayInterval: 1.seconds,
decayToZero: 0.01,
retainScore: 10.seconds,
appSpecificWeight: 0.0,
ipColocationFactorWeight: 0.0,
ipColocationFactorThreshold: 1.0,
behaviourPenaltyWeight: -1.0,
behaviourPenaltyDecay: 0.999,
)
proc validateParameters*(parameters: GossipSubParams): Result[void, cstring] =
if (parameters.dOut >= parameters.dLow) or
(parameters.dOut > (parameters.d div 2)):
err("gossipsub: dOut parameter error, Number of outbound connections to keep in the mesh. Must be less than D_lo and at most D/2")
elif parameters.gossipThreshold >= 0:
err("gossipsub: gossipThreshold parameter error, Must be < 0")
elif parameters.publishThreshold >= parameters.gossipThreshold:
err("gossipsub: publishThreshold parameter error, Must be < gossipThreshold")
elif parameters.graylistThreshold >= parameters.publishThreshold:
err("gossipsub: graylistThreshold parameter error, Must be < publishThreshold")
elif parameters.acceptPXThreshold < 0:
err("gossipsub: acceptPXThreshold parameter error, Must be >= 0")
elif parameters.opportunisticGraftThreshold < 0:
err("gossipsub: opportunisticGraftThreshold parameter error, Must be >= 0")
elif parameters.decayToZero > 0.5 or parameters.decayToZero <= 0.0:
err("gossipsub: decayToZero parameter error, Should be close to 0.0")
elif parameters.appSpecificWeight < 0:
err("gossipsub: appSpecificWeight parameter error, Must be positive")
elif parameters.ipColocationFactorWeight > 0:
err("gossipsub: ipColocationFactorWeight parameter error, Must be negative or 0")
elif parameters.ipColocationFactorThreshold < 1.0:
err("gossipsub: ipColocationFactorThreshold parameter error, Must be at least 1")
elif parameters.behaviourPenaltyWeight >= 0:
err("gossipsub: behaviourPenaltyWeight parameter error, Must be negative")
elif parameters.behaviourPenaltyDecay < 0 or parameters.behaviourPenaltyDecay >= 1:
err("gossipsub: behaviourPenaltyDecay parameter error, Must be between 0 and 1")
else:
ok()
proc init*(_: type[TopicParams]): TopicParams =
TopicParams(
topicWeight: 0.0, # disable score
timeInMeshWeight: 0.01,
timeInMeshQuantum: 1.seconds,
timeInMeshCap: 10.0,
firstMessageDeliveriesWeight: 1.0,
firstMessageDeliveriesDecay: 0.5,
firstMessageDeliveriesCap: 10.0,
meshMessageDeliveriesWeight: -1.0,
meshMessageDeliveriesDecay: 0.5,
meshMessageDeliveriesCap: 10,
meshMessageDeliveriesThreshold: 1,
meshMessageDeliveriesWindow: 5.milliseconds,
meshMessageDeliveriesActivation: 10.seconds,
meshFailurePenaltyWeight: -1.0,
meshFailurePenaltyDecay: 0.5,
invalidMessageDeliveriesWeight: -1.0,
invalidMessageDeliveriesDecay: 0.5
)
proc validateParameters*(parameters: TopicParams): Result[void, cstring] =
if parameters.timeInMeshWeight <= 0.0 or parameters.timeInMeshWeight > 1.0:
err("gossipsub: timeInMeshWeight parameter error, Must be a small positive value")
elif parameters.timeInMeshCap <= 0.0:
err("gossipsub: timeInMeshCap parameter error, Should be a positive value")
elif parameters.firstMessageDeliveriesWeight <= 0.0:
err("gossipsub: firstMessageDeliveriesWeight parameter error, Should be a positive value")
elif parameters.meshMessageDeliveriesWeight >= 0.0:
err("gossipsub: meshMessageDeliveriesWeight parameter error, Should be a negative value")
elif parameters.meshMessageDeliveriesThreshold <= 0.0:
err("gossipsub: meshMessageDeliveriesThreshold parameter error, Should be a positive value")
elif parameters.meshMessageDeliveriesCap < parameters.meshMessageDeliveriesThreshold:
err("gossipsub: meshMessageDeliveriesCap parameter error, Should be >= meshMessageDeliveriesThreshold")
elif parameters.meshMessageDeliveriesWindow > 100.milliseconds:
err("gossipsub: meshMessageDeliveriesWindow parameter error, Should be small, 1-5ms")
elif parameters.meshFailurePenaltyWeight >= 0.0:
err("gossipsub: meshFailurePenaltyWeight parameter error, Should be a negative value")
elif parameters.invalidMessageDeliveriesWeight >= 0.0:
err("gossipsub: invalidMessageDeliveriesWeight parameter error, Should be a negative value")
else:
ok()
func byScore(x,y: PubSubPeer): int = system.cmp(x.score, y.score)
method init*(g: GossipSub) =
proc handler(conn: Connection, proto: string) {.async.} =
## main protocol handler that gets triggered on every
## connection for a protocol string
## e.g. ``/floodsub/1.0.0``, etc...
##
try:
await g.handleConn(conn, proto)
except CancelledError:
# This is top-level procedure which will work as separate task, so it
# do not need to propogate CancelledError.
trace "Unexpected cancellation in gossipsub handler", conn
except CatchableError as exc:
trace "GossipSub handler leaks an error", exc = exc.msg, conn
g.handler = handler
g.codecs &= GossipSubCodec
g.codecs &= GossipSubCodec_10
method onNewPeer(g: GossipSub, peer: PubSubPeer) =
if peer notin g.peerStats:
# new peer
g.peerStats[peer] = PeerStats()
peer.iWantBudget = IWantPeerBudget
peer.iHaveBudget = IHavePeerBudget
return
else:
# we knew this peer
discard
proc grafted(g: GossipSub, p: PubSubPeer, topic: string) =
g.peerStats.withValue(p, stats) do:
var info = stats.topicInfos.getOrDefault(topic)
info.graftTime = Moment.now()
info.meshTime = 0.seconds
info.inMesh = true
info.meshMessageDeliveriesActive = false
# mgetOrPut does not work, so we gotta do this without referencing
stats.topicInfos[topic] = info
assert(g.peerStats[p].topicInfos[topic].inMesh == true)
trace "grafted", peer=p, topic
do:
g.onNewPeer(p)
g.grafted(p, topic)
proc pruned(g: GossipSub, p: PubSubPeer, topic: string) =
g.peerStats.withValue(p, stats) do:
when not defined(release):
g.prunedPeers.incl(p)
if topic in stats.topicInfos:
var info = stats.topicInfos[topic]
let topicParams = g.topicParams.mgetOrPut(topic, TopicParams.init())
# penalize a peer that delivered no message
let threshold = topicParams.meshMessageDeliveriesThreshold
if info.inMesh and info.meshMessageDeliveriesActive and info.meshMessageDeliveries < threshold:
let deficit = threshold - info.meshMessageDeliveries
info.meshFailurePenalty += deficit * deficit
info.inMesh = false
# mgetOrPut does not work, so we gotta do this without referencing
stats.topicInfos[topic] = info
trace "pruned", peer=p, topic
proc peerExchangeList(g: GossipSub, topic: string): seq[PeerInfoMsg] =
var peers = g.gossipsub.getOrDefault(topic, initHashSet[PubSubPeer]()).toSeq()
peers.keepIf do (x: PubSubPeer) -> bool:
x.score >= 0.0
# by spec, larger then Dhi, but let's put some hard caps
peers.setLen(min(peers.len, g.parameters.dHigh * 2))
peers.map do (x: PubSubPeer) -> PeerInfoMsg:
PeerInfoMsg(peerID: x.peerId.getBytes())
proc replenishFanout(g: GossipSub, topic: string) =
## get fanout peers for a topic
logScope: topic
trace "about to replenish fanout"
if g.fanout.peers(topic) < g.parameters.dLow:
trace "replenishing fanout", peers = g.fanout.peers(topic)
if topic in g.gossipsub:
for peer in g.gossipsub[topic]:
if g.fanout.addPeer(topic, peer):
if g.fanout.peers(topic) == g.parameters.d:
break
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_fanout
.set(g.fanout.peers(topic).int64, labelValues = [topic])
trace "fanout replenished with peers", peers = g.fanout.peers(topic)
method onPubSubPeerEvent*(p: GossipSub, peer: PubsubPeer, event: PubSubPeerEvent) {.gcsafe.} =
case event.kind
of PubSubPeerEventKind.Connected:
discard
of PubSubPeerEventKind.Disconnected:
# If a send connection is lost, it's better to remove peer from the mesh -
# if it gets reestablished, the peer will be readded to the mesh, and if it
# doesn't, well.. then we hope the peer is going away!
for topic, peers in p.mesh.mpairs():
p.pruned(peer, topic)
peers.excl(peer)
for _, peers in p.fanout.mpairs():
peers.excl(peer)
procCall FloodSub(p).onPubSubPeerEvent(peer, event)
proc rebalanceMesh(g: GossipSub, topic: string) {.async.} =
logScope:
topic
mesh = g.mesh.peers(topic)
gossipsub = g.gossipsub.peers(topic)
trace "rebalancing mesh"
# create a mesh topic that we're subscribing to
var
grafts, prunes, grafting: seq[PubSubPeer]
let npeers = g.mesh.peers(topic)
if npeers < g.parameters.dLow:
trace "replenishing mesh", peers = g.mesh.peers(topic)
# replenish the mesh if we're below Dlo
grafts = toSeq(
g.gossipsub.getOrDefault(topic, initHashSet[PubSubPeer]()) -
g.mesh.getOrDefault(topic, initHashSet[PubSubPeer]())
).filterIt(it.connected)
grafts.keepIf do (x: PubSubPeer) -> bool:
# avoid negative score peers
x.score >= 0.0 and
# don't pick explicit peers
x.peerId notin g.parameters.directPeers and
# and avoid peers we are backing off
x.peerId notin g.backingOff
# shuffle anyway, score might be not used
shuffle(grafts)
# sort peers by score, high score first since we graft
grafts.sort(byScore, SortOrder.Descending)
# Graft peers so we reach a count of D
grafts.setLen(min(grafts.len, g.parameters.d - g.mesh.peers(topic)))
trace "grafting", grafts = grafts.len
for peer in grafts:
if g.mesh.addPeer(topic, peer):
g.grafted(peer, topic)
g.fanout.removePeer(topic, peer)
grafting &= peer
else:
var meshPeers = toSeq(g.mesh.getOrDefault(topic, initHashSet[PubSubPeer]()))
meshPeers.keepIf do (x: PubSubPeer) -> bool: x.outbound
if meshPeers.len < g.parameters.dOut:
trace "replenishing mesh outbound quota", peers = g.mesh.peers(topic)
grafts = toSeq(
g.gossipsub.getOrDefault(topic, initHashSet[PubSubPeer]()) -
g.mesh.getOrDefault(topic, initHashSet[PubSubPeer]())
)
grafts.keepIf do (x: PubSubPeer) -> bool:
# get only outbound ones
x.outbound and
# avoid negative score peers
x.score >= 0.0 and
# don't pick explicit peers
x.peerId notin g.parameters.directPeers and
# and avoid peers we are backing off
x.peerId notin g.backingOff
# shuffle anyway, score might be not used
shuffle(grafts)
# sort peers by score, high score first, we are grafting
grafts.sort(byScore, SortOrder.Descending)
# Graft peers so we reach a count of D
grafts.setLen(min(grafts.len, g.parameters.dOut))
trace "grafting outbound peers", topic, peers = grafts.len
for peer in grafts:
if g.mesh.addPeer(topic, peer):
g.grafted(peer, topic)
g.fanout.removePeer(topic, peer)
grafting &= peer
if g.mesh.peers(topic) > g.parameters.dHigh:
# prune peers if we've gone over Dhi
prunes = toSeq(g.mesh[topic])
# avoid pruning peers we are currently grafting in this heartbeat
prunes.keepIf do (x: PubSubPeer) -> bool: x notin grafting
let mesh = prunes
# shuffle anyway, score might be not used
shuffle(prunes)
# sort peers by score (inverted), pruning, so low score peers are on top
prunes.sort(byScore, SortOrder.Ascending)
# keep high score peers
if prunes.len > g.parameters.dScore:
prunes.setLen(prunes.len - g.parameters.dScore)
# collect inbound/outbound info
var outbound: seq[PubSubPeer]
var inbound: seq[PubSubPeer]
for peer in prunes:
if peer.outbound:
outbound &= peer
else:
inbound &= peer
# ensure that there are at least D_out peers first and rebalance to g.d after that
let maxOutboundPrunes =
block:
var count = 0
for peer in mesh:
if peer.outbound:
inc count
count - g.parameters.dOut
outbound.setLen(min(outbound.len, max(0, maxOutboundPrunes)))
# concat remaining outbound peers
inbound &= outbound
let pruneLen = inbound.len - g.parameters.d
if pruneLen > 0:
# Ok we got some peers to prune,
# for this heartbeat let's prune those
shuffle(inbound)
inbound.setLen(pruneLen)
trace "pruning", prunes = inbound.len
for peer in inbound:
g.pruned(peer, topic)
g.mesh.removePeer(topic, peer)
# opportunistic grafting, by spec mesh should not be empty...
if g.mesh.peers(topic) > 1:
var peers = toSeq(g.mesh[topic])
# grafting so high score has priority
peers.sort(byScore, SortOrder.Descending)
let medianIdx = peers.len div 2
let median = peers[medianIdx]
if median.score < g.parameters.opportunisticGraftThreshold:
trace "median score below opportunistic threshold", score = median.score
var avail = toSeq(
g.gossipsub.getOrDefault(topic, initHashSet[PubSubPeer]()) -
g.mesh.getOrDefault(topic, initHashSet[PubSubPeer]())
)
avail.keepIf do (x: PubSubPeer) -> bool:
# avoid negative score peers
x.score >= median.score and
# don't pick explicit peers
x.peerId notin g.parameters.directPeers and
# and avoid peers we are backing off
x.peerId notin g.backingOff
# by spec, grab only 2
if avail.len > 2:
avail.setLen(2)
for peer in avail:
if g.mesh.addPeer(topic, peer):
g.grafted(peer, topic)
grafting &= peer
trace "opportunistic grafting", peer
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_gossipsub
.set(g.gossipsub.peers(topic).int64, labelValues = [topic])
libp2p_gossipsub_peers_per_topic_fanout
.set(g.fanout.peers(topic).int64, labelValues = [topic])
libp2p_gossipsub_peers_per_topic_mesh
.set(g.mesh.peers(topic).int64, labelValues = [topic])
trace "mesh balanced"
# Send changes to peers after table updates to avoid stale state
if grafts.len > 0:
let graft = RPCMsg(control: some(ControlMessage(graft: @[ControlGraft(topicID: topic)])))
g.broadcast(grafts, graft)
if prunes.len > 0:
let prune = RPCMsg(control: some(ControlMessage(
prune: @[ControlPrune(
topicID: topic,
peers: g.peerExchangeList(topic),
backoff: g.parameters.pruneBackoff.seconds.uint64)])))
g.broadcast(prunes, prune)
proc dropFanoutPeers(g: GossipSub) =
# drop peers that we haven't published to in
# GossipSubFanoutTTL seconds
let now = Moment.now()
for topic in toSeq(g.lastFanoutPubSub.keys):
let val = g.lastFanoutPubSub[topic]
if now > val:
g.fanout.del(topic)
g.lastFanoutPubSub.del(topic)
trace "dropping fanout topic", topic
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_fanout
.set(g.fanout.peers(topic).int64, labelValues = [topic])
proc getGossipPeers(g: GossipSub): Table[PubSubPeer, ControlMessage] {.gcsafe.} =
## gossip iHave messages to peers
##
trace "getting gossip peers (iHave)"
let topics = toHashSet(toSeq(g.mesh.keys)) + toHashSet(toSeq(g.fanout.keys))
for topic in topics:
if topic notin g.gossipsub:
trace "topic not in gossip array, skipping", topicID = topic
continue
let mids = g.mcache.window(topic)
if not mids.len > 0:
continue
let ihave = ControlIHave(topicID: topic, messageIDs: toSeq(mids))
let mesh = g.mesh.getOrDefault(topic)
let fanout = g.fanout.getOrDefault(topic)
let gossipPeers = mesh + fanout
var allPeers = toSeq(g.gossipsub.getOrDefault(topic))
allPeers.keepIf do (x: PubSubPeer) -> bool:
x.peerId notin g.parameters.directPeers and
x notin gossipPeers and
x.score >= g.parameters.gossipThreshold
var target = g.parameters.dLazy
let factor = (g.parameters.gossipFactor.float * allPeers.len.float).int
if factor > target:
target = min(factor, allPeers.len)
if target < allPeers.len:
shuffle(allPeers)
allPeers.setLen(target)
for peer in allPeers:
if peer notin result:
result[peer] = ControlMessage()
result[peer].ihave.add(ihave)
func `/`(a, b: Duration): float64 =
let
fa = float64(a.nanoseconds)
fb = float64(b.nanoseconds)
fa / fb
proc colocationFactor(g: GossipSub, peer: PubSubPeer): float64 =
if peer.connections.len == 0:
0.0
else:
let
address = peer.connections[0].observedAddr
ipPeers = g.peersInIP.getOrDefault(address)
len = ipPeers.len.float64
if len > g.parameters.ipColocationFactorThreshold:
let over = len - g.parameters.ipColocationFactorThreshold
over * over
else:
# lazy update peersInIP
if address notin g.peersInIP:
g.peersInIP[address] = initHashSet[PubSubPeer]()
g.peersInIP[address].incl(peer)
0.0
proc updateScores(g: GossipSub) = # avoid async
trace "updating scores", peers = g.peers.len
let now = Moment.now()
var evicting: seq[PubSubPeer]
for peer, stats in g.peerStats.mpairs:
trace "updating peer score", peer
var n_topics = 0
var is_grafted = 0
if not peer.connected:
if now > stats.expire:
evicting.add(peer)
trace "evicted peer from memory", peer
continue
# Per topic
for topic, topicParams in g.topicParams:
var info = stats.topicInfos.getOrDefault(topic)
inc n_topics
# Scoring
var topicScore = 0'f64
if info.inMesh:
inc is_grafted
info.meshTime = now - info.graftTime
if info.meshTime > topicParams.meshMessageDeliveriesActivation:
info.meshMessageDeliveriesActive = true
var p1 = info.meshTime / topicParams.timeInMeshQuantum
if p1 > topicParams.timeInMeshCap:
p1 = topicParams.timeInMeshCap
trace "p1", peer, p1
topicScore += p1 * topicParams.timeInMeshWeight
else:
info.meshMessageDeliveriesActive = false
topicScore += info.firstMessageDeliveries * topicParams.firstMessageDeliveriesWeight
trace "p2", peer, p2 = info.firstMessageDeliveries
if info.meshMessageDeliveriesActive:
if info.meshMessageDeliveries < topicParams.meshMessageDeliveriesThreshold:
let deficit = topicParams.meshMessageDeliveriesThreshold - info.meshMessageDeliveries
let p3 = deficit * deficit
trace "p3", peer, p3
topicScore += p3 * topicParams.meshMessageDeliveriesWeight
topicScore += info.meshFailurePenalty * topicParams.meshFailurePenaltyWeight
trace "p3b", peer, p3b = info.meshFailurePenalty
topicScore += info.invalidMessageDeliveries * info.invalidMessageDeliveries * topicParams.invalidMessageDeliveriesWeight
trace "p4", p4 = info.invalidMessageDeliveries * info.invalidMessageDeliveries
trace "updated peer topic's scores", peer, topic, info, topicScore
peer.score += topicScore * topicParams.topicWeight
# Score decay
info.firstMessageDeliveries *= topicParams.firstMessageDeliveriesDecay
if info.firstMessageDeliveries < g.parameters.decayToZero:
info.firstMessageDeliveries = 0
info.meshMessageDeliveries *= topicParams.meshMessageDeliveriesDecay
if info.meshMessageDeliveries < g.parameters.decayToZero:
info.meshMessageDeliveries = 0
info.meshFailurePenalty *= topicParams.meshFailurePenaltyDecay
if info.meshFailurePenalty < g.parameters.decayToZero:
info.meshFailurePenalty = 0
info.invalidMessageDeliveries *= topicParams.invalidMessageDeliveriesDecay
if info.invalidMessageDeliveries < g.parameters.decayToZero:
info.invalidMessageDeliveries = 0
# Wrap up
# commit our changes, mgetOrPut does NOT work as wanted with value types (lent?)
stats.topicInfos[topic] = info
peer.score += peer.appScore * g.parameters.appSpecificWeight
peer.score += peer.behaviourPenalty * peer.behaviourPenalty * g.parameters.behaviourPenaltyWeight
peer.score += g.colocationFactor(peer) * g.parameters.ipColocationFactorWeight
# decay behaviourPenalty
peer.behaviourPenalty *= g.parameters.behaviourPenaltyDecay
if peer.behaviourPenalty < g.parameters.decayToZero:
peer.behaviourPenalty = 0
trace "updated peer's score", peer, score = peer.score, n_topics, is_grafted
for peer in evicting:
g.peerStats.del(peer)
trace "updated scores", peers = g.peers.len
proc heartbeat(g: GossipSub) {.async.} =
while g.heartbeatRunning:
try:
trace "running heartbeat", instance = cast[int](g)
# remove expired backoffs
block:
let now = Moment.now()
var expired = toSeq(g.backingOff.pairs())
expired.keepIf do (pair: tuple[peer: PeerID, expire: Moment]) -> bool:
now >= pair.expire
for (peer, _) in expired:
g.backingOff.del(peer)
# reset IWANT budget
# reset IHAVE cap
block:
for peer in g.peers.values:
peer.iWantBudget = IWantPeerBudget
peer.iHaveBudget = IHavePeerBudget
g.updateScores()
var
totalMeshPeers = 0
totalGossipPeers = 0
for t in toSeq(g.topics.keys):
# prune every negative score peer
# do this before relance
# in order to avoid grafted -> pruned in the same cycle
let meshPeers = g.mesh.getOrDefault(t)
let gossipPeers = g.gossipsub.getOrDefault(t)
# this will be changed by rebalance but does not matter
totalMeshPeers += meshPeers.len
totalGossipPeers += gossipPeers.len
var prunes: seq[PubSubPeer]
for peer in meshPeers:
if peer.score < 0.0:
g.pruned(peer, t)
g.mesh.removePeer(t, peer)
prunes &= peer
let prune = RPCMsg(control: some(ControlMessage(
prune: @[ControlPrune(
topicID: t,
peers: g.peerExchangeList(t),
backoff: g.parameters.pruneBackoff.seconds.uint64)])))
g.broadcast(prunes, prune)
await g.rebalanceMesh(t)
libp2p_gossipsub_peers_mesh_sum.set(totalMeshPeers.int64)
libp2p_gossipsub_peers_gossipsub_sum.set(totalGossipPeers.int64)
g.dropFanoutPeers()
# replenish known topics to the fanout
for t in toSeq(g.fanout.keys):
g.replenishFanout(t)
let peers = g.getGossipPeers()
for peer, control in peers:
g.peers.withValue(peer.peerId, pubsubPeer) do:
g.send(
pubsubPeer[],
RPCMsg(control: some(control)))
g.mcache.shift() # shift the cache
except CancelledError as exc:
raise exc
except CatchableError as exc:
warn "exception ocurred in gossipsub heartbeat", exc = exc.msg,
trace = exc.getStackTrace()
for trigger in g.heartbeatEvents:
trace "firing heartbeat event", instance = cast[int](g)
trigger.fire()
await sleepAsync(g.parameters.heartbeatInterval)
method unsubscribePeer*(g: GossipSub, peer: PeerID) =
## handle peer disconnects
##
trace "unsubscribing gossipsub peer", peer
let pubSubPeer = g.peers.getOrDefault(peer)
if pubSubPeer.isNil:
trace "no peer to unsubscribe", peer
return
# remove from peer IPs collection too
if pubSubPeer.connections.len > 0:
g.peersInIP.withValue(pubSubPeer.connections[0].observedAddr, s) do:
s[].excl(pubSubPeer)
for t in toSeq(g.gossipsub.keys):
g.gossipsub.removePeer(t, pubSubPeer)
# also try to remove from explicit table here
g.explicit.removePeer(t, pubSubPeer)
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_gossipsub
.set(g.gossipsub.peers(t).int64, labelValues = [t])
for t in toSeq(g.mesh.keys):
g.pruned(pubSubPeer, t)
g.mesh.removePeer(t, pubSubPeer)
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_mesh
.set(g.mesh.peers(t).int64, labelValues = [t])
for t in toSeq(g.fanout.keys):
g.fanout.removePeer(t, pubSubPeer)
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_fanout
.set(g.fanout.peers(t).int64, labelValues = [t])
g.peerStats[pubSubPeer].expire = Moment.now() + g.parameters.retainScore
for topic, info in g.peerStats[pubSubPeer].topicInfos.mpairs:
info.firstMessageDeliveries = 0
procCall FloodSub(g).unsubscribePeer(peer)
method subscribeTopic*(g: GossipSub,
topic: string,
subscribe: bool,
peer: PubSubPeer) {.gcsafe.} =
# Skip floodsub - we don't want it to add the peer to `g.floodsub`
procCall PubSub(g).subscribeTopic(topic, subscribe, peer)
logScope:
peer
topic
g.onNewPeer(peer)
if subscribe:
trace "peer subscribed to topic"
# subscribe remote peer to the topic
discard g.gossipsub.addPeer(topic, peer)
if peer.peerId in g.parameters.directPeers:
discard g.explicit.addPeer(topic, peer)
else:
trace "peer unsubscribed from topic"
# unsubscribe remote peer from the topic
g.gossipsub.removePeer(topic, peer)
g.mesh.removePeer(topic, peer)
g.fanout.removePeer(topic, peer)
if peer.peerId in g.parameters.directPeers:
g.explicit.removePeer(topic, peer)
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_mesh
.set(g.mesh.peers(topic).int64, labelValues = [topic])
libp2p_gossipsub_peers_per_topic_fanout
.set(g.fanout.peers(topic).int64, labelValues = [topic])
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_gossipsub
.set(g.gossipsub.peers(topic).int64, labelValues = [topic])
trace "gossip peers", peers = g.gossipsub.peers(topic), topic
proc punishPeer(g: GossipSub, peer: PubSubPeer, topics: seq[string]) =
for t in topics:
# ensure we init a new topic if unknown
let _ = g.topicParams.mgetOrPut(t, TopicParams.init())
# update stats
var tstats = g.peerStats[peer].topicInfos.getOrDefault(t)
tstats.invalidMessageDeliveries += 1
g.peerStats[peer].topicInfos[t] = tstats
proc handleGraft(g: GossipSub,
peer: PubSubPeer,
grafts: seq[ControlGraft]): seq[ControlPrune] =
for graft in grafts:
let topic = graft.topicID
logScope:
peer
topic
trace "peer grafted topic"
# It is an error to GRAFT on a explicit peer
if peer.peerId in g.parameters.directPeers:
# receiving a graft from a direct peer should yield a more prominent warning (protocol violation)
warn "attempt to graft an explicit peer", peer=peer.id,
topicID=graft.topicID
# and such an attempt should be logged and rejected with a PRUNE
result.add(ControlPrune(
topicID: graft.topicID,
peers: @[], # omitting heavy computation here as the remote did something illegal
backoff: g.parameters.pruneBackoff.seconds.uint64))
g.punishPeer(peer, @[topic])
continue
if peer.peerId in g.backingOff and g.backingOff[peer.peerId] > Moment.now():
trace "attempt to graft a backingOff peer", peer=peer.id,
topicID=graft.topicID,
expire=g.backingOff[peer.peerId]
# and such an attempt should be logged and rejected with a PRUNE
result.add(ControlPrune(
topicID: graft.topicID,
peers: @[], # omitting heavy computation here as the remote did something illegal
backoff: g.parameters.pruneBackoff.seconds.uint64))
g.punishPeer(peer, @[topic])
continue
if peer notin g.peerStats:
g.onNewPeer(peer)
# not in the spec exactly, but let's avoid way too low score peers
# other clients do it too also was an audit recommendation
if peer.score < g.parameters.publishThreshold:
continue
# If they send us a graft before they send us a subscribe, what should
# we do? For now, we add them to mesh but don't add them to gossipsub.
if topic in g.topics:
if g.mesh.peers(topic) < g.parameters.dHigh or peer.outbound:
# In the spec, there's no mention of DHi here, but implicitly, a
# peer will be removed from the mesh on next rebalance, so we don't want
# this peer to push someone else out
if g.mesh.addPeer(topic, peer):
g.grafted(peer, topic)
g.fanout.removePeer(topic, peer)
else:
trace "peer already in mesh"
else:
result.add(ControlPrune(
topicID: topic,
peers: g.peerExchangeList(topic),
backoff: g.parameters.pruneBackoff.seconds.uint64))
else:
trace "peer grafting topic we're not interested in", topic
# gossip 1.1, we do not send a control message prune anymore
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_mesh
.set(g.mesh.peers(topic).int64, labelValues = [topic])
libp2p_gossipsub_peers_per_topic_fanout
.set(g.fanout.peers(topic).int64, labelValues = [topic])
proc handlePrune(g: GossipSub, peer: PubSubPeer, prunes: seq[ControlPrune]) =
for prune in prunes:
trace "peer pruned topic", peer, topic = prune.topicID
# add peer backoff
if prune.backoff > 0:
let backoff = Moment.fromNow((prune.backoff + BackoffSlackTime).int64.seconds)
let current = g.backingOff.getOrDefault(peer.peerId)
if backoff > current:
g.backingOff[peer.peerId] = backoff
g.pruned(peer, prune.topicID)
g.mesh.removePeer(prune.topicID, peer)
# TODO peer exchange, we miss ambient peer discovery in libp2p, so we are blocked by that
# another option could be to implement signed peer records
## if peer.score > g.parameters.gossipThreshold and prunes.peers.len > 0:
when defined(libp2p_expensive_metrics):
libp2p_gossipsub_peers_per_topic_mesh
.set(g.mesh.peers(prune.topicID).int64, labelValues = [prune.topicID])
proc handleIHave(g: GossipSub,
peer: PubSubPeer,
ihaves: seq[ControlIHave]): ControlIWant =
if peer.score < g.parameters.gossipThreshold:
trace "ihave: ignoring low score peer", peer, score = peer.score
elif peer.iHaveBudget <= 0:
trace "ihave: ignoring out of budget peer", peer, score = peer.score
else:
var deIhaves = ihaves.deduplicate()
for ihave in deIhaves.mitems:
trace "peer sent ihave",
peer, topic = ihave.topicID, msgs = ihave.messageIDs
if ihave.topicID in g.mesh:
for m in ihave.messageIDs:
if m notin g.seen:
if peer.iHaveBudget > 0:
result.messageIDs.add(m)
dec peer.iHaveBudget
else:
return
# shuffling result.messageIDs before sending it out to increase the likelihood
# of getting an answer if the peer truncates the list due to internal size restrictions.
shuffle(result.messageIDs)
proc handleIWant(g: GossipSub,
peer: PubSubPeer,
iwants: seq[ControlIWant]): seq[Message] =
if peer.score < g.parameters.gossipThreshold:
trace "iwant: ignoring low score peer", peer, score = peer.score
elif peer.iWantBudget <= 0:
trace "iwant: ignoring out of budget peer", peer, score = peer.score
else:
var deIwants = iwants.deduplicate()
for iwant in deIwants:
for mid in iwant.messageIDs:
trace "peer sent iwant", peer, messageID = mid
let msg = g.mcache.get(mid)
if msg.isSome:
# avoid spam
if peer.iWantBudget > 0:
result.add(msg.get())
dec peer.iWantBudget
else:
return
method rpcHandler*(g: GossipSub,
peer: PubSubPeer,
rpcMsg: RPCMsg) {.async.} =
await procCall PubSub(g).rpcHandler(peer, rpcMsg)
for msg in rpcMsg.messages: # for every message
let msgId = g.msgIdProvider(msg)
if g.seen.put(msgId):
trace "Dropping already-seen message", msgId, peer
# make sure to update score tho before continuing
for t in msg.topicIDs: # for every topic in the message
let topicParams = g.topicParams.mgetOrPut(t, TopicParams.init())
# if in mesh add more delivery score
var stats = g.peerStats[peer].topicInfos.getOrDefault(t)
if stats.inMesh:
stats.meshMessageDeliveries += 1
if stats.meshMessageDeliveries > topicParams.meshMessageDeliveriesCap:
stats.meshMessageDeliveries = topicParams.meshMessageDeliveriesCap
# commit back to the table
g.peerStats[peer].topicInfos[t] = stats
continue
g.mcache.put(msgId, msg)
if (msg.signature.len > 0 or g.verifySignature) and not msg.verify():
# always validate if signature is present or required
debug "Dropping message due to failed signature verification", msgId, peer
g.punishPeer(peer, msg.topicIDs)
continue
if msg.seqno.len > 0 and msg.seqno.len != 8:
# if we have seqno should be 8 bytes long
debug "Dropping message due to invalid seqno length", msgId, peer
g.punishPeer(peer, msg.topicIDs)
continue
# g.anonymize needs no evaluation when receiving messages
# as we have a "lax" policy and allow signed messages
let validation = await g.validate(msg)
case validation
of ValidationResult.Reject:
debug "Dropping message after validation, reason: reject", msgId, peer
g.punishPeer(peer, msg.topicIDs)
continue
of ValidationResult.Ignore:
debug "Dropping message after validation, reason: ignore", msgId, peer
continue
of ValidationResult.Accept:
discard
var toSendPeers = initHashSet[PubSubPeer]()
for t in msg.topicIDs: # for every topic in the message
let topicParams = g.topicParams.mgetOrPut(t, TopicParams.init())
# contribute to peer score first delivery
var stats = g.peerStats[peer].topicInfos.getOrDefault(t)
stats.firstMessageDeliveries += 1
if stats.firstMessageDeliveries > topicParams.firstMessageDeliveriesCap:
stats.firstMessageDeliveries = topicParams.firstMessageDeliveriesCap
# if in mesh add more delivery score
if stats.inMesh:
stats.meshMessageDeliveries += 1
if stats.meshMessageDeliveries > topicParams.meshMessageDeliveriesCap:
stats.meshMessageDeliveries = topicParams.meshMessageDeliveriesCap
# commit back to the table
g.peerStats[peer].topicInfos[t] = stats
g.floodsub.withValue(t, peers): toSendPeers.incl(peers[])
g.mesh.withValue(t, peers): toSendPeers.incl(peers[])
await handleData(g, t, msg.data)
# In theory, if topics are the same in all messages, we could batch - we'd
# also have to be careful to only include validated messages
g.broadcast(toSeq(toSendPeers), RPCMsg(messages: @[msg]))
trace "forwared message to peers", peers = toSendPeers.len, msgId, peer
if rpcMsg.control.isSome:
let control = rpcMsg.control.get()
g.handlePrune(peer, control.prune)
var respControl: ControlMessage
respControl.iwant.add(g.handleIHave(peer, control.ihave))
respControl.prune.add(g.handleGraft(peer, control.graft))
let messages = g.handleIWant(peer, control.iwant)
if respControl.graft.len > 0 or respControl.prune.len > 0 or
respControl.ihave.len > 0 or messages.len > 0:
trace "sending control message", msg = shortLog(respControl), peer
g.send(
peer,
RPCMsg(control: some(respControl), messages: messages))
method subscribe*(g: GossipSub,
topic: string,
handler: TopicHandler) {.async.} =
await procCall PubSub(g).subscribe(topic, handler)
# if we have a fanout on this topic break it
if topic in g.fanout:
g.fanout.del(topic)
await g.rebalanceMesh(topic)
method unsubscribe*(g: GossipSub,
topics: seq[TopicPair]) {.async.} =
await procCall PubSub(g).unsubscribe(topics)
for (topic, handler) in topics:
# delete from mesh only if no handlers are left
if topic notin g.topics:
if topic in g.mesh:
let peers = g.mesh[topic]
g.mesh.del(topic)
g.topicParams.del(topic)
for peer in peers:
g.pruned(peer, topic)
let prune = RPCMsg(control: some(ControlMessage(
prune: @[ControlPrune(
topicID: topic,
peers: g.peerExchangeList(topic),
backoff: g.parameters.pruneBackoff.seconds.uint64)])))
g.broadcast(toSeq(peers), prune)
method unsubscribeAll*(g: GossipSub, topic: string) {.async.} =
await procCall PubSub(g).unsubscribeAll(topic)
if topic in g.mesh:
let peers = g.mesh.getOrDefault(topic)
g.mesh.del(topic)
for peer in peers:
g.pruned(peer, topic)
let prune = RPCMsg(control: some(ControlMessage(
prune: @[ControlPrune(
topicID: topic,
peers: g.peerExchangeList(topic),
backoff: g.parameters.pruneBackoff.seconds.uint64)])))
g.broadcast(toSeq(peers), prune)
method publish*(g: GossipSub,
topic: string,
data: seq[byte]): Future[int] {.async.} =
# base returns always 0
discard await procCall PubSub(g).publish(topic, data)
logScope: topic
trace "Publishing message on topic", data = data.shortLog
if topic.len <= 0: # data could be 0/empty
debug "Empty topic, skipping publish"
return 0
var peers: HashSet[PubSubPeer]
if g.parameters.floodPublish:
# With flood publishing enabled, the mesh is used when propagating messages from other peers,
# but a peer's own messages will always be published to all known peers in the topic.
for peer in g.gossipsub.getOrDefault(topic):
if peer.score >= g.parameters.publishThreshold:
trace "publish: including flood/high score peer", peer
peers.incl(peer)
# add always direct peers
peers.incl(g.explicit.getOrDefault(topic))
if topic in g.topics: # if we're subscribed use the mesh
peers.incl(g.mesh.getOrDefault(topic))
else: # not subscribed, send to fanout peers
# try optimistically
peers.incl(g.fanout.getOrDefault(topic))
if peers.len == 0:
# ok we had nothing.. let's try replenish inline
g.replenishFanout(topic)
peers.incl(g.fanout.getOrDefault(topic))
# even if we couldn't publish,
# we still attempted to publish
# on the topic, so it makes sense
# to update the last topic publish
# time
g.lastFanoutPubSub[topic] = Moment.fromNow(g.parameters.fanoutTTL)
if peers.len == 0:
debug "No peers for topic, skipping publish"
return 0
inc g.msgSeqno
let
msg =
if g.anonymize:
Message.init(none(PeerInfo), data, topic, none(uint64), false)
else:
Message.init(some(g.peerInfo), data, topic, some(g.msgSeqno), g.sign)
msgId = g.msgIdProvider(msg)
logScope: msgId
trace "Created new message", msg = shortLog(msg), peers = peers.len
if g.seen.put(msgId):
# custom msgid providers might cause this
trace "Dropping already-seen message"
return 0
g.mcache.put(msgId, msg)
g.broadcast(toSeq(peers), RPCMsg(messages: @[msg]))
when defined(libp2p_expensive_metrics):
if peers.len > 0:
libp2p_pubsub_messages_published.inc(labelValues = [topic])
trace "Published message to peers"
return peers.len
proc maintainDirectPeers(g: GossipSub) {.async.} =
while g.heartbeatRunning:
for id in g.parameters.directPeers:
let peer = g.peers.getOrDefault(id)
if peer == nil:
# this creates a new peer and assigns the current switch to it
# as a result the next time we try to Send we will as well try to open a connection
# see pubsubpeer.nim send and such
discard g.getOrCreatePeer(id, g.codecs)
await sleepAsync(1.minutes)
method start*(g: GossipSub) {.async.} =
trace "gossipsub start"
if not g.heartbeatFut.isNil:
warn "Starting gossipsub twice"
return
g.heartbeatRunning = true
g.heartbeatFut = g.heartbeat()
g.directPeersLoop = g.maintainDirectPeers()
method stop*(g: GossipSub) {.async.} =
trace "gossipsub stop"
if g.heartbeatFut.isNil:
warn "Stopping gossipsub without starting it"
return
# stop heartbeat interval
g.heartbeatRunning = false
g.directPeersLoop.cancel()
if not g.heartbeatFut.finished:
trace "awaiting last heartbeat"
await g.heartbeatFut
trace "heartbeat stopped"
g.heartbeatFut = nil
method initPubSub*(g: GossipSub) =
procCall FloodSub(g).initPubSub()
if not g.parameters.explicit:
g.parameters = GossipSubParams.init()
g.parameters.validateParameters().tryGet()
randomize()
g.mcache = MCache.init(g.parameters.historyGossip, g.parameters.historyLength)
g.mesh = initTable[string, HashSet[PubSubPeer]]() # meshes - topic to peer
g.fanout = initTable[string, HashSet[PubSubPeer]]() # fanout - topic to peer
g.gossipsub = initTable[string, HashSet[PubSubPeer]]()# topic to peer map of all gossipsub peers
g.lastFanoutPubSub = initTable[string, Moment]() # last publish time for fanout topics
g.gossip = initTable[string, seq[ControlIHave]]() # pending gossip
g.control = initTable[string, ControlMessage]() # pending control messages