Files
lighthouse/beacon_node/network/src/sync/manager.rs
2019-09-03 00:34:41 +10:00

960 lines
42 KiB
Rust

//! The `ImportManager` facilities the block syncing logic of lighthouse. The current networking
//! specification provides two methods from which to obtain blocks from peers. The `BeaconBlocks`
//! request and the `RecentBeaconBlocks` request. The former is used to obtain a large number of
//! blocks and the latter allows for searching for blocks given a block-hash.
//!
//! These two RPC methods are designed for two type of syncing.
//! - Long range (batch) sync, when a client is out of date and needs to the latest head.
//! - Parent lookup - when a peer provides us a block whose parent is unknown to us.
//!
//! Both of these syncing strategies are built into the `ImportManager`.
//!
//!
//! Currently the long-range (batch) syncing method functions by opportunistically downloading
//! batches blocks from all peers who know about a chain that we do not. When a new peer connects
//! which has a later head that is greater than `SLOT_IMPORT_TOLERANCE` from our current head slot,
//! the manager's state becomes `Syncing` and begins a batch syncing process with this peer. If
//! further peers connect, this process is run in parallel with those peers, until our head is
//! within `SLOT_IMPORT_TOLERANCE` of all connected peers.
//!
//! Batch Syncing
//!
//! This syncing process start by requesting `MAX_BLOCKS_PER_REQUEST` blocks from a peer with an
//! unknown chain (with a greater slot height) starting from our current head slot. If the earliest
//! block returned is known to us, then the group of blocks returned form part of a known chain,
//! and we process this batch of blocks, before requesting more batches forward and processing
//! those in turn until we reach the peer's chain's head. If the first batch doesn't contain a
//! block we know of, we must iteratively request blocks backwards (until our latest finalized head
//! slot) until we find a common ancestor before we can start processing the blocks. If no common
//! ancestor is found, the peer has a chain which is not part of our finalized head slot and we
//! drop the peer and the downloaded blocks.
//! Once we are fully synced with all known peers, the state of the manager becomes `Regular` which
//! then allows for parent lookups of propagated blocks.
//!
//! A schematic version of this logic with two chain variations looks like the following.
//!
//! |----------------------|---------------------------------|
//! ^finalized head ^current local head ^remotes head
//!
//!
//! An example of the remotes chain diverging before our current head.
//! |---------------------------|
//! ^---------------------------------------------|
//! ^chain diverges |initial batch| ^remotes head
//!
//! In this example, we cannot process the initial batch as it is not on a known chain. We must
//! then backwards sync until we reach a common chain to begin forwarding batch syncing.
//!
//!
//! Parent Lookup
//!
//! When a block with an unknown parent is received and we are in `Regular` sync mode, the block is
//! queued for lookup. A round-robin approach is used to request the parent from the known list of
//! fully sync'd peers. If `PARENT_FAIL_TOLERANCE` attempts at requesting the block fails, we
//! drop the propagated block and downvote the peer that sent it to us.
use super::simple_sync::{PeerSyncInfo, FUTURE_SLOT_TOLERANCE};
use beacon_chain::{BeaconChain, BeaconChainTypes, BlockProcessingOutcome};
use eth2_libp2p::rpc::methods::*;
use eth2_libp2p::rpc::RequestId;
use eth2_libp2p::PeerId;
use slog::{debug, info, trace, warn, Logger};
use smallvec::SmallVec;
use std::collections::{HashMap, HashSet};
use std::ops::{Add, Sub};
use std::sync::{Arc, Weak};
use types::{BeaconBlock, EthSpec, Hash256, Slot};
/// Blocks are downloaded in batches from peers. This constant specifies how many blocks per batch
/// is requested. Currently the value is small for testing. This will be incremented for
/// production.
const MAX_BLOCKS_PER_REQUEST: u64 = 10;
/// The number of slots ahead of us that is allowed before requesting a long-range (batch) Sync
/// from a peer. If a peer is within this tolerance (forwards or backwards), it is treated as a
/// fully sync'd peer.
const SLOT_IMPORT_TOLERANCE: usize = 10;
/// How many attempts we try to find a parent of a block before we give up trying .
const PARENT_FAIL_TOLERANCE: usize = 3;
/// The maximum depth we will search for a parent block. In principle we should have sync'd any
/// canonical chain to its head once the peer connects. A chain should not appear where it's depth
/// is further back than the most recent head slot.
const PARENT_DEPTH_TOLERANCE: usize = SLOT_IMPORT_TOLERANCE * 2;
/// The number of empty batches we tolerate before dropping the peer. This prevents endless
/// requests to peers who never return blocks.
const EMPTY_BATCH_TOLERANCE: usize = 100;
#[derive(PartialEq)]
/// The current state of a block or batches lookup.
enum BlockRequestsState {
/// The object is queued to be downloaded from a peer but has not yet been requested.
Queued,
/// The batch or parent has been requested with the `RequestId` and we are awaiting a response.
Pending(RequestId),
/// The downloaded blocks are ready to be processed by the beacon chain. For a batch process
/// this means we have found a common chain.
ReadyToProcess,
/// A failure has occurred and we will drop and downvote the peer that caused the request.
Failed,
}
/// The state of batch requests.
enum SyncDirection {
/// The batch has just been initialised and we need to check to see if a backward sync is
/// required on first batch response.
Initial,
/// We are syncing forwards, the next batch should contain higher slot numbers than is
/// predecessor.
Forwards,
/// We are syncing backwards and looking for a common ancestor chain before we can start
/// processing the downloaded blocks.
Backwards,
}
/// `BlockRequests` keep track of the long-range (batch) sync process per peer.
struct BlockRequests<T: EthSpec> {
/// The peer's head slot and the target of this batch download.
target_head_slot: Slot,
/// The peer's head root, used to specify which chain of blocks we are downloading from the
/// blocks.
target_head_root: Hash256,
/// The blocks that we have currently downloaded from the peer that are yet to be processed.
downloaded_blocks: Vec<BeaconBlock<T>>,
/// The number of empty batches we have consecutively received. If a peer returns more than
/// EMPTY_BATCHES_TOLERANCE, they are dropped.
consecutive_empty_batches: usize,
/// The current state of this batch request.
state: BlockRequestsState,
/// Specifies the current direction of this batch request.
sync_direction: SyncDirection,
/// The current `start_slot` of the batched block request.
current_start_slot: Slot,
}
/// Maintains a sequential list of parents to lookup and the lookup's current state.
struct ParentRequests<T: EthSpec> {
/// The blocks that have currently been downloaded.
downloaded_blocks: Vec<BeaconBlock<T>>,
/// The number of failed attempts to retrieve a parent block. If too many attempts occur, this
/// lookup is failed and rejected.
failed_attempts: usize,
/// The peer who last submitted a block. If the chain ends or fails, this is the peer that is
/// downvoted.
last_submitted_peer: PeerId,
/// The current state of the parent lookup.
state: BlockRequestsState,
}
impl<T: EthSpec> BlockRequests<T> {
/// Gets the next start slot for a batch and transitions the state to a Queued state.
fn update_start_slot(&mut self) {
match self.sync_direction {
SyncDirection::Initial | SyncDirection::Forwards => {
self.current_start_slot += Slot::from(MAX_BLOCKS_PER_REQUEST);
}
SyncDirection::Backwards => {
self.current_start_slot -= Slot::from(MAX_BLOCKS_PER_REQUEST);
}
}
self.state = BlockRequestsState::Queued;
}
}
#[derive(PartialEq, Debug, Clone)]
/// The current state of the `ImportManager`.
enum ManagerState {
/// The manager is performing a long-range (batch) sync. In this mode, parent lookups are
/// disabled.
Syncing,
/// The manager is up to date with all known peers and is connected to at least one
/// fully-syncing peer. In this state, parent lookups are enabled.
Regular,
/// No useful peers are connected. Long-range sync's cannot proceed and we have no useful
/// peers to download parents for. More peers need to be connected before we can proceed.
Stalled,
}
/// The output states that can occur from driving (polling) the manager state machine.
pub(crate) enum ImportManagerOutcome {
/// There is no further work to complete. The manager is waiting for further input.
Idle,
/// A `BeaconBlocks` request is required.
RequestBlocks {
peer_id: PeerId,
request_id: RequestId,
request: BeaconBlocksRequest,
},
/// A `RecentBeaconBlocks` request is required.
RecentRequest(PeerId, RecentBeaconBlocksRequest),
/// Updates information with peer via requesting another HELLO handshake.
Hello(PeerId),
/// A peer has caused a punishable error and should be downvoted.
DownvotePeer(PeerId),
}
/// The primary object for handling and driving all the current syncing logic. It maintains the
/// current state of the syncing process, the number of useful peers, downloaded blocks and
/// controls the logic behind both the long-range (batch) sync and the on-going potential parent
/// look-up of blocks.
pub struct ImportManager<T: BeaconChainTypes> {
/// List of events to be processed externally.
event_queue: SmallVec<[ImportManagerOutcome; 20]>,
/// A weak reference to the underlying beacon chain.
chain: Weak<BeaconChain<T>>,
/// The current state of the import manager.
state: ManagerState,
/// A collection of `BlockRequest` per peer that is currently being downloaded. Used in the
/// long-range (batch) sync process.
import_queue: HashMap<PeerId, BlockRequests<T::EthSpec>>,
/// A collection of parent block lookups.
parent_queue: SmallVec<[ParentRequests<T::EthSpec>; 3]>,
/// The collection of known, connected, fully-sync'd peers.
full_peers: HashSet<PeerId>,
/// The current request Id. This is used to keep track of responses to various outbound
/// requests. This is an internal accounting mechanism, request id's are never sent to any
/// peers.
current_req_id: usize,
/// The logger for the import manager.
log: Logger,
}
impl<T: BeaconChainTypes> ImportManager<T> {
/// Generates a new `ImportManager` given a logger and an Arc reference to a beacon chain. The
/// import manager keeps a weak reference to the beacon chain, which allows the chain to be
/// dropped during the syncing process. The syncing handles this termination gracefully.
pub fn new(beacon_chain: Arc<BeaconChain<T>>, log: &slog::Logger) -> Self {
ImportManager {
event_queue: SmallVec::new(),
chain: Arc::downgrade(&beacon_chain),
state: ManagerState::Regular,
import_queue: HashMap::new(),
parent_queue: SmallVec::new(),
full_peers: HashSet::new(),
current_req_id: 0,
log: log.clone(),
}
}
/// A peer has connected which has blocks that are unknown to us.
///
/// This function handles the logic associated with the connection of a new peer. If the peer
/// is sufficiently ahead of our current head, a long-range (batch) sync is started and
/// batches of blocks are queued to download from the peer. Batched blocks begin at our
/// current head. If the resulting downloaded blocks are part of our current chain, we
/// continue with a forward sync. If not, we download blocks (in batches) backwards until we
/// reach a common ancestor. Batches are then processed and downloaded sequentially forwards.
///
/// If the peer is within the `SLOT_IMPORT_TOLERANCE`, then it's head is sufficiently close to
/// ours that we consider it fully sync'd with respect to our current chain.
pub fn add_peer(&mut self, peer_id: PeerId, remote: PeerSyncInfo) {
// ensure the beacon chain still exists
let chain = match self.chain.upgrade() {
Some(chain) => chain,
None => {
warn!(self.log,
"Beacon chain dropped. Peer not considered for sync";
"peer_id" => format!("{:?}", peer_id));
return;
}
};
let local = PeerSyncInfo::from(&chain);
// If a peer is within SLOT_IMPORT_TOLERANCE from our head slot, ignore a batch sync,
// consider it a fully-sync'd peer.
if remote.head_slot.sub(local.head_slot).as_usize() < SLOT_IMPORT_TOLERANCE {
trace!(self.log, "Ignoring full sync with peer";
"peer" => format!("{:?}", peer_id),
"peer_head_slot" => remote.head_slot,
"local_head_slot" => local.head_slot,
);
// remove the peer from the queue if it exists
self.import_queue.remove(&peer_id);
self.add_full_peer(peer_id);
//
return;
}
// Check if the peer is significantly is behind us. If within `SLOT_IMPORT_TOLERANCE`
// treat them as a fully synced peer. If not, ignore them in the sync process
if local.head_slot.sub(remote.head_slot).as_usize() < SLOT_IMPORT_TOLERANCE {
self.add_full_peer(peer_id.clone());
} else {
debug!(
self.log,
"Out of sync peer connected";
"peer" => format!("{:?}", peer_id),
);
return;
}
// Check if we are already downloading blocks from this peer, if so update, if not set up
// a new request structure
if let Some(block_requests) = self.import_queue.get_mut(&peer_id) {
// update the target head slot
if remote.head_slot > block_requests.target_head_slot {
block_requests.target_head_slot = remote.head_slot;
}
} else {
// not already downloading blocks from this peer
let block_requests = BlockRequests {
target_head_slot: remote.head_slot, // this should be larger than the current head. It is checked in the SyncManager before add_peer is called
target_head_root: remote.head_root,
consecutive_empty_batches: 0,
downloaded_blocks: Vec::new(),
state: BlockRequestsState::Queued,
sync_direction: SyncDirection::Initial,
current_start_slot: chain.best_slot(),
};
self.import_queue.insert(peer_id, block_requests);
}
}
/// A `BeaconBlocks` request has received a response. This function process the response.
pub fn beacon_blocks_response(
&mut self,
peer_id: PeerId,
request_id: RequestId,
mut blocks: Vec<BeaconBlock<T::EthSpec>>,
) {
// ensure the underlying chain still exists
let chain = match self.chain.upgrade() {
Some(chain) => chain,
None => {
debug!(self.log, "Chain dropped. Sync terminating");
self.event_queue.clear();
return;
}
};
// find the request associated with this response
let block_requests = match self
.import_queue
.get_mut(&peer_id)
.filter(|r| r.state == BlockRequestsState::Pending(request_id))
{
Some(req) => req,
_ => {
// No pending request, invalid request_id or coding error
warn!(self.log, "BeaconBlocks response unknown"; "request_id" => request_id);
return;
}
};
// If we are syncing up to a target head block, at least the target head block should be
// returned. If we are syncing back to our last finalized block the request should return
// at least the last block we received (last known block). In diagram form:
//
// unknown blocks requested blocks downloaded blocks
// |-------------------|------------------------|------------------------|
// ^finalized slot ^ requested start slot ^ last known block ^ remote head
if blocks.is_empty() {
debug!(self.log, "BeaconBlocks response was empty"; "request_id" => request_id);
block_requests.consecutive_empty_batches += 1;
if block_requests.consecutive_empty_batches >= EMPTY_BATCH_TOLERANCE {
warn!(self.log, "Peer returned too many empty block batches";
"peer" => format!("{:?}", peer_id));
block_requests.state = BlockRequestsState::Failed;
} else {
block_requests.update_start_slot();
}
return;
}
block_requests.consecutive_empty_batches = 0;
// verify the range of received blocks
// Note that the order of blocks is verified in block processing
let last_sent_slot = blocks[blocks.len() - 1].slot;
if block_requests.current_start_slot > blocks[0].slot
|| block_requests
.current_start_slot
.add(MAX_BLOCKS_PER_REQUEST)
< last_sent_slot
{
warn!(self.log, "BeaconBlocks response returned out of range blocks";
"request_id" => request_id,
"response_initial_slot" => blocks[0].slot,
"requested_initial_slot" => block_requests.current_start_slot);
self.event_queue
.push(ImportManagerOutcome::DownvotePeer(peer_id));
// consider this sync failed
block_requests.state = BlockRequestsState::Failed;
return;
}
// Determine if more blocks need to be downloaded. There are a few cases:
// - We are in initial sync mode - We have requested blocks and need to determine if this
// is part of a known chain to determine the whether to start syncing backwards or continue
// syncing forwards.
// - We are syncing backwards and need to verify if we have found a common ancestor in
// order to start processing the downloaded blocks.
// - We are syncing forwards. We mark this as complete and check if any further blocks are
// required to download when processing the batch.
match block_requests.sync_direction {
SyncDirection::Initial => {
block_requests.downloaded_blocks.append(&mut blocks);
// this batch is the first batch downloaded. Check if we can process or if we need
// to backwards search.
//TODO: Decide which is faster. Reading block from db and comparing or calculating
//the hash tree root and comparing.
let earliest_slot = block_requests.downloaded_blocks[0].slot;
if Some(block_requests.downloaded_blocks[0].canonical_root())
== chain.root_at_slot(earliest_slot)
{
// we have a common head, start processing and begin a forwards sync
block_requests.sync_direction = SyncDirection::Forwards;
block_requests.state = BlockRequestsState::ReadyToProcess;
return;
}
// no common head, begin a backwards search
block_requests.sync_direction = SyncDirection::Backwards;
block_requests.current_start_slot =
std::cmp::min(chain.best_slot(), block_requests.downloaded_blocks[0].slot);
block_requests.update_start_slot();
}
SyncDirection::Forwards => {
// continue processing all blocks forwards, verify the end in the processing
block_requests.downloaded_blocks.append(&mut blocks);
block_requests.state = BlockRequestsState::ReadyToProcess;
}
SyncDirection::Backwards => {
block_requests.downloaded_blocks.splice(..0, blocks);
// verify the request hasn't failed by having no common ancestor chain
// get our local finalized_slot
let local_finalized_slot = {
let state = &chain.head().beacon_state;
state
.finalized_checkpoint
.epoch
.start_slot(T::EthSpec::slots_per_epoch())
};
if local_finalized_slot >= block_requests.current_start_slot {
warn!(self.log, "Peer returned an unknown chain."; "request_id" => request_id);
block_requests.state = BlockRequestsState::Failed;
return;
}
// check if we have reached a common chain ancestor
let earliest_slot = block_requests.downloaded_blocks[0].slot;
if Some(block_requests.downloaded_blocks[0].canonical_root())
== chain.root_at_slot(earliest_slot)
{
// we have a common head, start processing and begin a forwards sync
block_requests.sync_direction = SyncDirection::Forwards;
block_requests.state = BlockRequestsState::ReadyToProcess;
return;
}
// no common chain, haven't passed last_finalized_head, so continue backwards
// search
block_requests.update_start_slot();
}
}
}
pub fn recent_blocks_response(
&mut self,
peer_id: PeerId,
request_id: RequestId,
blocks: Vec<BeaconBlock<T::EthSpec>>,
) {
// find the request
let parent_request = match self
.parent_queue
.iter_mut()
.find(|request| request.state == BlockRequestsState::Pending(request_id))
{
Some(req) => req,
None => {
// No pending request, invalid request_id or coding error
warn!(self.log, "RecentBeaconBlocks response unknown"; "request_id" => request_id);
return;
}
};
// if an empty response is given, the peer didn't have the requested block, try again
if blocks.is_empty() {
parent_request.failed_attempts += 1;
parent_request.state = BlockRequestsState::Queued;
parent_request.last_submitted_peer = peer_id;
return;
}
// currently only support a single block lookup. Reject any response that has more than 1
// block
if blocks.len() != 1 {
//TODO: Potentially downvote the peer
debug!(self.log, "Peer sent more than 1 parent. Ignoring";
"peer_id" => format!("{:?}", peer_id),
"no_parents" => blocks.len()
);
return;
}
// queue for processing
parent_request.state = BlockRequestsState::ReadyToProcess;
}
pub fn _inject_error(_peer_id: PeerId, _id: RequestId) {
//TODO: Remove block state from pending
}
pub fn peer_disconnect(&mut self, peer_id: &PeerId) {
self.import_queue.remove(peer_id);
self.full_peers.remove(peer_id);
self.update_state();
}
pub fn add_full_peer(&mut self, peer_id: PeerId) {
debug!(
self.log, "Fully synced peer added";
"peer" => format!("{:?}", peer_id),
);
self.full_peers.insert(peer_id);
self.update_state();
}
pub fn add_unknown_block(&mut self, block: BeaconBlock<T::EthSpec>, peer_id: PeerId) {
// if we are not in regular sync mode, ignore this block
if let ManagerState::Regular = self.state {
return;
}
// make sure this block is not already being searched for
// TODO: Potentially store a hashset of blocks for O(1) lookups
for parent_req in self.parent_queue.iter() {
if let Some(_) = parent_req
.downloaded_blocks
.iter()
.find(|d_block| d_block == &&block)
{
// we are already searching for this block, ignore it
return;
}
}
let req = ParentRequests {
downloaded_blocks: vec![block],
failed_attempts: 0,
last_submitted_peer: peer_id,
state: BlockRequestsState::Queued,
};
self.parent_queue.push(req);
}
pub(crate) fn poll(&mut self) -> ImportManagerOutcome {
loop {
//TODO: Optimize the lookups. Potentially keep state of whether each of these functions
//need to be called.
// only break once everything has been processed
let mut re_run = false;
// only process batch requests if there are any
if !self.import_queue.is_empty() {
// process potential block requests
self.process_potential_block_requests();
// process any complete long-range batches
re_run = self.process_complete_batches();
}
// only process parent objects if we are in regular sync
if let ManagerState::Regular = self.state {
// process any parent block lookup-requests
self.process_parent_requests();
// process any complete parent lookups
re_run = self.process_complete_parent_requests();
}
// return any queued events
if !self.event_queue.is_empty() {
let event = self.event_queue.remove(0);
self.event_queue.shrink_to_fit();
return event;
}
// update the state of the manager
self.update_state();
if !re_run {
break;
}
}
return ImportManagerOutcome::Idle;
}
fn update_state(&mut self) {
let previous_state = self.state.clone();
self.state = {
if !self.import_queue.is_empty() {
ManagerState::Syncing
} else if !self.full_peers.is_empty() {
ManagerState::Regular
} else {
ManagerState::Stalled
}
};
if self.state != previous_state {
info!(self.log, "Syncing state updated";
"old_state" => format!("{:?}", previous_state),
"new_state" => format!("{:?}", self.state),
);
}
}
fn process_potential_block_requests(&mut self) {
// check if an outbound request is required
// Managing a fixed number of outbound requests is maintained at the RPC protocol libp2p
// layer and not needed here. Therefore we create many outbound requests and let the RPC
// handle the number of simultaneous requests. Request all queued objects.
// remove any failed batches
let debug_log = &self.log;
self.import_queue.retain(|peer_id, block_request| {
if let BlockRequestsState::Failed = block_request.state {
debug!(debug_log, "Block import from peer failed";
"peer_id" => format!("{:?}", peer_id),
"downloaded_blocks" => block_request.downloaded_blocks.len()
);
false
} else {
true
}
});
// process queued block requests
for (peer_id, block_requests) in self
.import_queue
.iter_mut()
.find(|(_peer_id, req)| req.state == BlockRequestsState::Queued)
{
let request_id = self.current_req_id;
block_requests.state = BlockRequestsState::Pending(request_id);
self.current_req_id += 1;
let request = BeaconBlocksRequest {
head_block_root: block_requests.target_head_root,
start_slot: block_requests.current_start_slot.as_u64(),
count: MAX_BLOCKS_PER_REQUEST,
step: 0,
};
self.event_queue.push(ImportManagerOutcome::RequestBlocks {
peer_id: peer_id.clone(),
request,
request_id,
});
}
}
fn process_complete_batches(&mut self) -> bool {
// flag to indicate if the manager can be switched to idle or not
let mut re_run = false;
// create reference variables to be moved into subsequent closure
let chain_ref = self.chain.clone();
let log_ref = &self.log;
let event_queue_ref = &mut self.event_queue;
self.import_queue.retain(|peer_id, block_requests| {
// check that the chain still exists
if let Some(chain) = chain_ref.upgrade() {
let downloaded_blocks =
std::mem::replace(&mut block_requests.downloaded_blocks, Vec::new());
let last_element = block_requests.downloaded_blocks.len() - 1;
let start_slot = block_requests.downloaded_blocks[0].slot;
let end_slot = block_requests.downloaded_blocks[last_element].slot;
match process_blocks(chain, downloaded_blocks, log_ref) {
Ok(()) => {
debug!(log_ref, "Blocks processed successfully";
"peer" => format!("{:?}", peer_id),
"start_slot" => start_slot,
"end_slot" => end_slot,
"no_blocks" => last_element + 1,
);
// check if the batch is complete, by verifying if we have reached the
// target head
if end_slot >= block_requests.target_head_slot {
// Completed, re-hello the peer to ensure we are up to the latest head
event_queue_ref.push(ImportManagerOutcome::Hello(peer_id.clone()));
// remove the request
false
} else {
// have not reached the end, queue another batch
block_requests.update_start_slot();
re_run = true;
// keep the batch
true
}
}
Err(e) => {
warn!(log_ref, "Block processing failed";
"peer" => format!("{:?}", peer_id),
"start_slot" => start_slot,
"end_slot" => end_slot,
"no_blocks" => last_element + 1,
"error" => format!("{:?}", e),
);
event_queue_ref.push(ImportManagerOutcome::DownvotePeer(peer_id.clone()));
false
}
}
} else {
// chain no longer exists, empty the queue and return
event_queue_ref.clear();
return false;
}
});
re_run
}
fn process_parent_requests(&mut self) {
// check to make sure there are peers to search for the parent from
if self.full_peers.is_empty() {
return;
}
// remove any failed requests
let debug_log = &self.log;
self.parent_queue.retain(|parent_request| {
if parent_request.state == BlockRequestsState::Failed {
debug!(debug_log, "Parent import failed";
"block" => format!("{:?}",parent_request.downloaded_blocks[0].canonical_root()),
"ancestors_found" => parent_request.downloaded_blocks.len()
);
false
} else {
true
}
});
// check if parents need to be searched for
for parent_request in self.parent_queue.iter_mut() {
if parent_request.failed_attempts >= PARENT_FAIL_TOLERANCE {
parent_request.state = BlockRequestsState::Failed;
continue;
} else if parent_request.state == BlockRequestsState::Queued {
// check the depth isn't too large
if parent_request.downloaded_blocks.len() >= PARENT_DEPTH_TOLERANCE {
parent_request.state = BlockRequestsState::Failed;
continue;
}
parent_request.state = BlockRequestsState::Pending(self.current_req_id);
self.current_req_id += 1;
let last_element_index = parent_request.downloaded_blocks.len() - 1;
let parent_hash = parent_request.downloaded_blocks[last_element_index].parent_root;
let req = RecentBeaconBlocksRequest {
block_roots: vec![parent_hash],
};
// select a random fully synced peer to attempt to download the parent block
let peer_id = self.full_peers.iter().next().expect("List is not empty");
self.event_queue
.push(ImportManagerOutcome::RecentRequest(peer_id.clone(), req));
}
}
}
fn process_complete_parent_requests(&mut self) -> bool {
// returned value indicating whether the manager can be switched to idle or not
let mut re_run = false;
// Find any parent_requests ready to be processed
for completed_request in self
.parent_queue
.iter_mut()
.filter(|req| req.state == BlockRequestsState::ReadyToProcess)
{
// verify the last added block is the parent of the last requested block
let last_index = completed_request.downloaded_blocks.len() - 1;
let expected_hash = completed_request.downloaded_blocks[last_index].parent_root;
// Note: the length must be greater than 1 so this cannot panic.
let block_hash = completed_request.downloaded_blocks[last_index - 1].canonical_root();
if block_hash != expected_hash {
// remove the head block
let _ = completed_request.downloaded_blocks.pop();
completed_request.state = BlockRequestsState::Queued;
//TODO: Potentially downvote the peer
let peer = completed_request.last_submitted_peer.clone();
debug!(self.log, "Peer sent invalid parent. Ignoring";
"peer_id" => format!("{:?}",peer),
"received_block" => format!("{}", block_hash),
"expected_parent" => format!("{}", expected_hash),
);
re_run = true;
self.event_queue
.push(ImportManagerOutcome::DownvotePeer(peer));
}
// try and process the list of blocks up to the requested block
while !completed_request.downloaded_blocks.is_empty() {
let block = completed_request
.downloaded_blocks
.pop()
.expect("Block must exist exist");
// check if the chain exists
if let Some(chain) = self.chain.upgrade() {
match chain.process_block(block.clone()) {
Ok(BlockProcessingOutcome::ParentUnknown { parent: _ }) => {
// need to keep looking for parents
completed_request.downloaded_blocks.push(block);
completed_request.state = BlockRequestsState::Queued;
re_run = true;
break;
}
Ok(BlockProcessingOutcome::Processed { block_root: _ }) => {}
Ok(outcome) => {
// it's a future slot or an invalid block, remove it and try again
completed_request.failed_attempts += 1;
trace!(
self.log, "Invalid parent block";
"outcome" => format!("{:?}", outcome),
"peer" => format!("{:?}", completed_request.last_submitted_peer),
);
completed_request.state = BlockRequestsState::Queued;
re_run = true;
self.event_queue.push(ImportManagerOutcome::DownvotePeer(
completed_request.last_submitted_peer.clone(),
));
return re_run;
}
Err(e) => {
completed_request.failed_attempts += 1;
warn!(
self.log, "Parent processing error";
"error" => format!("{:?}", e)
);
completed_request.state = BlockRequestsState::Queued;
re_run = true;
self.event_queue.push(ImportManagerOutcome::DownvotePeer(
completed_request.last_submitted_peer.clone(),
));
return re_run;
}
}
} else {
// chain doesn't exist - clear the event queue and return
self.event_queue.clear();
return false;
}
}
}
// remove any fully processed parent chains
self.parent_queue.retain(|req| {
if req.state == BlockRequestsState::ReadyToProcess {
false
} else {
true
}
});
re_run
}
}
// Helper function to process blocks
fn process_blocks<T: BeaconChainTypes>(
chain: Arc<BeaconChain<T>>,
blocks: Vec<BeaconBlock<T::EthSpec>>,
log: &Logger,
) -> Result<(), String> {
for block in blocks {
let processing_result = chain.process_block(block.clone());
if let Ok(outcome) = processing_result {
match outcome {
BlockProcessingOutcome::Processed { block_root } => {
// The block was valid and we processed it successfully.
trace!(
log, "Imported block from network";
"slot" => block.slot,
"block_root" => format!("{}", block_root),
);
}
BlockProcessingOutcome::ParentUnknown { parent } => {
// blocks should be sequential and all parents should exist
trace!(
log, "ParentBlockUnknown";
"parent_root" => format!("{}", parent),
"baby_block_slot" => block.slot,
);
return Err(format!(
"Block at slot {} has an unknown parent.",
block.slot
));
}
BlockProcessingOutcome::FutureSlot {
present_slot,
block_slot,
} => {
if present_slot + FUTURE_SLOT_TOLERANCE >= block_slot {
// The block is too far in the future, drop it.
trace!(
log, "FutureBlock";
"msg" => "block for future slot rejected, check your time",
"present_slot" => present_slot,
"block_slot" => block_slot,
"FUTURE_SLOT_TOLERANCE" => FUTURE_SLOT_TOLERANCE,
);
return Err(format!(
"Block at slot {} is too far in the future",
block.slot
));
} else {
// The block is in the future, but not too far.
trace!(
log, "QueuedFutureBlock";
"msg" => "queuing future block, check your time",
"present_slot" => present_slot,
"block_slot" => block_slot,
"FUTURE_SLOT_TOLERANCE" => FUTURE_SLOT_TOLERANCE,
);
}
}
BlockProcessingOutcome::FinalizedSlot => {
trace!(
log, "Finalized or earlier block processed";
"outcome" => format!("{:?}", outcome),
);
// block reached our finalized slot or was earlier, move to the next block
}
_ => {
trace!(
log, "InvalidBlock";
"msg" => "peer sent invalid block",
"outcome" => format!("{:?}", outcome),
);
return Err(format!("Invalid block at slot {}", block.slot));
}
}
} else {
trace!(
log, "BlockProcessingFailure";
"msg" => "unexpected condition in processing block.",
"outcome" => format!("{:?}", processing_result)
);
return Err(format!(
"Unexpected block processing error: {:?}",
processing_result
));
}
}
Ok(())
}