nimbus-eth2/beacon_chain/sync_protocol.nim

249 lines
8.7 KiB
Nim

import
options, tables, sets, macros,
chronicles, chronos, metrics, stew/ranges/bitranges,
spec/[datatypes, crypto, digest, helpers], eth/rlp,
beacon_node_types, eth2_network, block_pool, ssz
when networkBackend == rlpx:
import eth/rlp/options as rlpOptions
template libp2pProtocol*(name: string, version: int) {.pragma.}
elif networkBackend == libp2p:
import libp2p/switch
declarePublicGauge libp2p_peers, "Number of libp2p peers"
logScope:
topics = "sync"
type
ValidatorSetDeltaFlags {.pure.} = enum
Activation = 0
Exit = 1
ValidatorChangeLogEntry* = object
case kind*: ValidatorSetDeltaFlags
of Activation:
pubkey: ValidatorPubKey
else:
index: uint32
BeaconBlockCallback* = proc(blck: BeaconBlock) {.gcsafe.}
BeaconSyncNetworkState* = ref object
blockPool*: BlockPool
forkVersion*: array[4, byte]
onBeaconBlock*: BeaconBlockCallback
BeaconSyncPeerState* = ref object
initialStatusReceived: bool
BlockRootSlot* = object
blockRoot: Eth2Digest
slot: Slot
const
MAX_REQUESTED_BLOCKS = 20'u64
func init*(
v: BeaconSyncNetworkState, blockPool: BlockPool,
forkVersion: array[4, byte], onBeaconBlock: BeaconBlockCallback) =
v.blockPool = blockPool
v.forkVersion = forkVersion
v.onBeaconBlock = onBeaconBlock
proc importBlocks(state: BeaconSyncNetworkState,
blocks: openarray[BeaconBlock]) {.gcsafe.} =
for blk in blocks:
state.onBeaconBlock(blk)
info "Forward sync imported blocks", len = blocks.len
type
StatusMsg = object
forkVersion*: array[4, byte]
finalizedRoot*: Eth2Digest
finalizedEpoch*: Epoch
headRoot*: Eth2Digest
headSlot*: Slot
proc getCurrentStatus(state: BeaconSyncNetworkState): StatusMsg {.gcsafe.} =
let
blockPool = state.blockPool
finalizedHead = blockPool.finalizedHead
headBlock = blockPool.head.blck
headRoot = headBlock.root
headSlot = headBlock.slot
finalizedEpoch = finalizedHead.slot.compute_epoch_at_slot()
StatusMsg(
fork_version: state.forkVersion,
finalizedRoot: finalizedHead.blck.root,
finalizedEpoch: finalizedEpoch,
headRoot: headRoot,
headSlot: headSlot)
proc handleInitialStatus(peer: Peer,
state: BeaconSyncNetworkState,
ourStatus: StatusMsg,
theirStatus: StatusMsg) {.async, gcsafe.}
p2pProtocol BeaconSync(version = 1,
rlpxName = "bcs",
networkState = BeaconSyncNetworkState,
peerState = BeaconSyncPeerState):
onPeerConnected do (peer: Peer):
if peer.wasDialed:
let
ourStatus = peer.networkState.getCurrentStatus()
# TODO: The timeout here is so high only because we fail to
# respond in time due to high CPU load in our single thread.
theirStatus = await peer.status(ourStatus, timeout = 60.seconds)
if theirStatus.isSome:
await peer.handleInitialStatus(peer.networkState, ourStatus, theirStatus.get)
else:
warn "Status response not received in time"
onPeerDisconnected do (peer: Peer):
libp2p_peers.set peer.network.peers.len.int64
requestResponse:
proc status(peer: Peer, theirStatus: StatusMsg) {.libp2pProtocol("status", 1).} =
let
ourStatus = peer.networkState.getCurrentStatus()
trace "Sending status msg", ourStatus
await response.send(ourStatus)
if not peer.state.initialStatusReceived:
peer.state.initialStatusReceived = true
await peer.handleInitialStatus(peer.networkState, ourStatus, theirStatus)
proc statusResp(peer: Peer, msg: StatusMsg)
proc goodbye(peer: Peer, reason: DisconnectionReason) {.libp2pProtocol("goodbye", 1).}
requestResponse:
proc beaconBlocksByRange(
peer: Peer,
headBlockRoot: Eth2Digest,
startSlot: Slot,
count: uint64,
step: uint64) {.
libp2pProtocol("beacon_blocks_by_range", 1).} =
trace "got range request", peer, count, startSlot, headBlockRoot, step
if count > 0'u64:
let count = if step != 0: min(count, MAX_REQUESTED_BLOCKS.uint64) else: 1
let pool = peer.networkState.blockPool
var results: array[MAX_REQUESTED_BLOCKS, BlockRef]
let
lastPos = min(count.int, results.len) - 1
firstPos = pool.getBlockRange(headBlockRoot, startSlot, step,
results.toOpenArray(0, lastPos))
for i in firstPos.int .. lastPos.int:
trace "wrote response block", slot = results[i].slot
await response.write(pool.get(results[i]).data)
proc beaconBlocksByRoot(
peer: Peer,
blockRoots: openarray[Eth2Digest]) {.
libp2pProtocol("beacon_blocks_by_root", 1).} =
let
pool = peer.networkState.blockPool
for root in blockRoots:
let blockRef = pool.getRef(root)
if not isNil(blockRef):
await response.write(pool.get(blockRef).data)
proc beaconBlocks(
peer: Peer,
blocks: openarray[BeaconBlock])
proc handleInitialStatus(peer: Peer,
state: BeaconSyncNetworkState,
ourStatus: StatusMsg,
theirStatus: StatusMsg) {.async, gcsafe.} =
when networkBackend == libp2p:
# TODO: This doesn't seem like an appropraite place for this call,
# but it's hard to pick a better place at the moment.
# nim-libp2p plans to add a general `onPeerConnected` callback which
# will allow us to implement the subscription earlier.
# The root of the problem is that both sides must call `subscribeToPeer`
# before any GossipSub traffic will flow between them.
await peer.network.switch.subscribeToPeer(peer.info)
if theirStatus.forkVersion != state.forkVersion:
notice "Irrelevant peer",
peer, theirFork = theirStatus.forkVersion, ourFork = state.forkVersion
await peer.disconnect(IrrelevantNetwork)
return
# TODO: onPeerConnected runs unconditionally for every connected peer, but we
# don't need to sync with everybody. The beacon node should detect a situation
# where it needs to sync and it should execute the sync algorithm with a certain
# number of randomly selected peers. The algorithm itself must be extracted in a proc.
try:
libp2p_peers.set peer.network.peers.len.int64
debug "Peer connected. Initiating sync", peer,
localHeadSlot = ourStatus.headSlot,
remoteHeadSlot = theirStatus.headSlot,
remoteHeadRoot = theirStatus.headRoot
let bestDiff = cmp((ourStatus.finalizedEpoch, ourStatus.headSlot),
(theirStatus.finalizedEpoch, theirStatus.headSlot))
if bestDiff >= 0:
# Nothing to do?
debug "Nothing to sync", peer
else:
# TODO: Check for WEAK_SUBJECTIVITY_PERIOD difference and terminate the
# connection if it's too big.
var s = ourStatus.headSlot + 1
var theirStatus = theirStatus
while s <= theirStatus.headSlot:
let numBlocksToRequest = min(uint64(theirStatus.headSlot - s) + 1,
MAX_REQUESTED_BLOCKS)
debug "Requesting blocks", peer, remoteHeadSlot = theirStatus.headSlot,
ourHeadSlot = s,
numBlocksToRequest
# TODO: The timeout here is so high only because we fail to
# respond in time due to high CPU load in our single thread.
let blocks = await peer.beaconBlocksByRange(theirStatus.headRoot, s,
numBlocksToRequest, 1'u64,
timeout = 60.seconds)
if blocks.isSome:
info "got blocks", total = blocks.get.len
if blocks.get.len == 0:
info "Got 0 blocks while syncing", peer
break
state.importBlocks(blocks.get)
let lastSlot = blocks.get[^1].slot
if lastSlot <= s:
info "Slot did not advance during sync", peer
break
s = lastSlot + 1
# TODO: Maybe this shouldn't happen so often.
# The alternative could be watching up a timer here.
let statusResp = await peer.status(state.getCurrentStatus())
if statusResp.isSome:
theirStatus = statusResp.get
else:
# We'll ignore this error and we'll try to request
# another range optimistically. If that fails, the
# syncing will be interrupted.
discard
else:
error "Did not get any blocks from peer. Aborting sync."
break
except CatchableError as e:
warn "Failed to sync with peer", peer, err = e.msg