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Altair networking (#2300)

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## Issue Addressed

Resolves #2278 

## Proposed Changes

Implements the networking components for the Altair hard fork https://github.com/ethereum/eth2.0-specs/blob/dev/specs/altair/p2p-interface.md

## Additional Info

This PR acts as the base branch for networking changes and tracks https://github.com/sigp/lighthouse/pull/2279 . Changes to gossip, rpc and discovery can be separate PRs to be merged here for ease of review.

Co-authored-by: realbigsean <seananderson33@gmail.com>
This commit is contained in:
Pawan Dhananjay
2021-08-04 01:44:57 +00:00
parent 6a620a31da
commit e8c0d1f19b
51 changed files with 4038 additions and 1354 deletions
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350
beacon_node/network/src/subnet_service/sync_subnets.rs Normal file
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//! This service keeps track of which sync committee subnet the beacon node should be subscribed to at any
//! given time. It schedules subscriptions to sync committee subnets and requests peer discoveries.
use std::collections::{hash_map::Entry, HashMap, VecDeque};
use std::pin::Pin;
use std::sync::Arc;
use std::task::{Context, Poll};
use std::time::Duration;
use futures::prelude::*;
use slog::{debug, error, o, trace, warn};
use super::SubnetServiceMessage;
use beacon_chain::{BeaconChain, BeaconChainTypes};
use eth2_libp2p::{NetworkConfig, Subnet, SubnetDiscovery};
use hashset_delay::HashSetDelay;
use slot_clock::SlotClock;
use types::{Epoch, EthSpec, SyncCommitteeSubscription, SyncSubnetId};
use crate::metrics;
/// The minimum number of slots ahead that we attempt to discover peers for a subscription. If the
/// slot is less than this number, skip the peer discovery process.
/// Subnet discovery query takes atmost 30 secs, 2 slots take 24s.
const MIN_PEER_DISCOVERY_SLOT_LOOK_AHEAD: u64 = 2;
/// A particular subnet at a given slot.
#[derive(PartialEq, Eq, Hash, Clone, Debug)]
pub struct ExactSubnet {
/// The `SyncSubnetId` associated with this subnet.
pub subnet_id: SyncSubnetId,
/// The epoch until which we need to stay subscribed to the subnet.
pub until_epoch: Epoch,
}
pub struct SyncCommitteeService<T: BeaconChainTypes> {
/// Queued events to return to the driving service.
events: VecDeque<SubnetServiceMessage>,
/// A reference to the beacon chain to process received attestations.
pub(crate) beacon_chain: Arc<BeaconChain<T>>,
/// The collection of all currently subscribed subnets.
subscriptions: HashMap<SyncSubnetId, Epoch>,
/// A collection of timeouts for when to unsubscribe from a subnet.
unsubscriptions: HashSetDelay<SyncSubnetId>,
/// The waker for the current thread.
waker: Option<std::task::Waker>,
/// The discovery mechanism of lighthouse is disabled.
discovery_disabled: bool,
/// We are always subscribed to all subnets.
subscribe_all_subnets: bool,
/// The logger for the attestation service.
log: slog::Logger,
}
impl<T: BeaconChainTypes> SyncCommitteeService<T> {
/* Public functions */
pub fn new(
beacon_chain: Arc<BeaconChain<T>>,
config: &NetworkConfig,
log: &slog::Logger,
) -> Self {
let log = log.new(o!("service" => "sync_committee_service"));
let spec = &beacon_chain.spec;
let epoch_duration_secs =
beacon_chain.slot_clock.slot_duration().as_secs() * T::EthSpec::slots_per_epoch();
let default_timeout =
epoch_duration_secs.saturating_mul(spec.epochs_per_sync_committee_period.as_u64());
SyncCommitteeService {
events: VecDeque::with_capacity(10),
beacon_chain,
subscriptions: HashMap::new(),
unsubscriptions: HashSetDelay::new(Duration::from_secs(default_timeout)),
waker: None,
subscribe_all_subnets: config.subscribe_all_subnets,
discovery_disabled: config.disable_discovery,
log,
}
}
/// Return count of all currently subscribed subnets.
#[cfg(test)]
pub fn subscription_count(&self) -> usize {
use types::consts::altair::SYNC_COMMITTEE_SUBNET_COUNT;
if self.subscribe_all_subnets {
SYNC_COMMITTEE_SUBNET_COUNT as usize
} else {
self.subscriptions.len()
}
}
/// Processes a list of sync committee subscriptions.
///
/// This will:
/// - Search for peers for required subnets.
/// - Request subscriptions required subnets.
/// - Build the timeouts for each of these events.
///
/// This returns a result simply for the ergonomics of using ?. The result can be
/// safely dropped.
pub fn validator_subscriptions(
&mut self,
subscriptions: Vec<SyncCommitteeSubscription>,
) -> Result<(), String> {
let mut subnets_to_discover = Vec::new();
for subscription in subscriptions {
metrics::inc_counter(&metrics::SYNC_COMMITTEE_SUBSCRIPTION_REQUESTS);
//NOTE: We assume all subscriptions have been verified before reaching this service
// Registers the validator with the subnet service.
// This will subscribe to long-lived random subnets if required.
trace!(self.log,
"Sync committee subscription";
"subscription" => ?subscription,
);
let subnet_ids = match SyncSubnetId::compute_subnets_for_sync_committee::<T::EthSpec>(
&subscription.sync_committee_indices,
) {
Ok(subnet_ids) => subnet_ids,
Err(e) => {
warn!(self.log,
"Failed to compute subnet id for sync committee subscription";
"error" => ?e,
"validator_index" => subscription.validator_index
);
continue;
}
};
for subnet_id in subnet_ids {
let exact_subnet = ExactSubnet {
subnet_id,
until_epoch: subscription.until_epoch,
};
subnets_to_discover.push(exact_subnet.clone());
if let Err(e) = self.subscribe_to_subnet(exact_subnet.clone()) {
warn!(self.log,
"Subscription to sync subnet error";
"error" => e,
"validator_index" => subscription.validator_index,
);
} else {
trace!(self.log,
"Subscribed to subnet for sync committee duties";
"exact_subnet" => ?exact_subnet,
"validator_index" => subscription.validator_index
);
}
}
}
// If the discovery mechanism isn't disabled, attempt to set up a peer discovery for the
// required subnets.
if !self.discovery_disabled {
if let Err(e) = self.discover_peers_request(subnets_to_discover.iter()) {
warn!(self.log, "Discovery lookup request error"; "error" => e);
};
}
// pre-emptively wake the thread to check for new events
if let Some(waker) = &self.waker {
waker.wake_by_ref();
}
Ok(())
}
/* Internal private functions */
/// Checks if there are currently queued discovery requests and the time required to make the
/// request.
///
/// If there is sufficient time, queues a peer discovery request for all the required subnets.
fn discover_peers_request<'a>(
&mut self,
exact_subnets: impl Iterator<Item = &'a ExactSubnet>,
) -> Result<(), &'static str> {
let current_slot = self
.beacon_chain
.slot_clock
.now()
.ok_or("Could not get the current slot")?;
let slots_per_epoch = T::EthSpec::slots_per_epoch();
let discovery_subnets: Vec<SubnetDiscovery> = exact_subnets
.filter_map(|exact_subnet| {
let until_slot = exact_subnet.until_epoch.end_slot(slots_per_epoch);
// check if there is enough time to perform a discovery lookup
if until_slot >= current_slot.saturating_add(MIN_PEER_DISCOVERY_SLOT_LOOK_AHEAD) {
// if the slot is more than epoch away, add an event to start looking for peers
// add one slot to ensure we keep the peer for the subscription slot
let min_ttl = self
.beacon_chain
.slot_clock
.duration_to_slot(until_slot + 1)
.map(|duration| std::time::Instant::now() + duration);
Some(SubnetDiscovery {
subnet: Subnet::SyncCommittee(exact_subnet.subnet_id),
min_ttl,
})
} else {
// We may want to check the global PeerInfo to see estimated timeouts for each
// peer before they can be removed.
warn!(self.log,
"Not enough time for a discovery search";
"subnet_id" => ?exact_subnet
);
None
}
})
.collect();
if !discovery_subnets.is_empty() {
self.events
.push_back(SubnetServiceMessage::DiscoverPeers(discovery_subnets));
}
Ok(())
}
/// Adds a subscription event and an associated unsubscription event if required.
fn subscribe_to_subnet(&mut self, exact_subnet: ExactSubnet) -> Result<(), &'static str> {
// Return if we have subscribed to all subnets
if self.subscribe_all_subnets {
return Ok(());
}
// Return if we already have a subscription for exact_subnet
if self.subscriptions.get(&exact_subnet.subnet_id) == Some(&exact_subnet.until_epoch) {
return Ok(());
}
// Return if we already have subscription set to expire later than the current request.
if let Some(until_epoch) = self.subscriptions.get(&exact_subnet.subnet_id) {
if *until_epoch >= exact_subnet.until_epoch {
return Ok(());
}
}
// initialise timing variables
let current_slot = self
.beacon_chain
.slot_clock
.now()
.ok_or("Could not get the current slot")?;
let slots_per_epoch = T::EthSpec::slots_per_epoch();
let until_slot = exact_subnet.until_epoch.end_slot(slots_per_epoch);
// Calculate the duration to the unsubscription event.
let expected_end_subscription_duration = if current_slot >= until_slot {
warn!(
self.log,
"Sync committee subscription is past expiration";
"current_slot" => current_slot,
"exact_subnet" => ?exact_subnet,
);
return Ok(());
} else {
let slot_duration = self.beacon_chain.slot_clock.slot_duration();
// the duration until we no longer need this subscription. We assume a single slot is
// sufficient.
self.beacon_chain
.slot_clock
.duration_to_slot(until_slot)
.ok_or("Unable to determine duration to unsubscription slot")?
+ slot_duration
};
if let Entry::Vacant(e) = self.subscriptions.entry(exact_subnet.subnet_id) {
// We are not currently subscribed and have no waiting subscription, create one
debug!(self.log, "Subscribing to subnet"; "subnet" => *exact_subnet.subnet_id, "until_epoch" => ?exact_subnet.until_epoch);
e.insert(exact_subnet.until_epoch);
self.events
.push_back(SubnetServiceMessage::Subscribe(Subnet::SyncCommittee(
exact_subnet.subnet_id,
)));
// add the subnet to the ENR bitfield
self.events
.push_back(SubnetServiceMessage::EnrAdd(Subnet::SyncCommittee(
exact_subnet.subnet_id,
)));
// add an unsubscription event to remove ourselves from the subnet once completed
self.unsubscriptions
.insert_at(exact_subnet.subnet_id, expected_end_subscription_duration);
} else {
// We are already subscribed, extend the unsubscription duration
self.unsubscriptions
.update_timeout(&exact_subnet.subnet_id, expected_end_subscription_duration);
}
Ok(())
}
/// A queued unsubscription is ready.
fn handle_unsubscriptions(&mut self, subnet_id: SyncSubnetId) {
debug!(self.log, "Unsubscribing from subnet"; "subnet" => *subnet_id);
self.subscriptions.remove(&subnet_id);
self.events
.push_back(SubnetServiceMessage::Unsubscribe(Subnet::SyncCommittee(
subnet_id,
)));
self.events
.push_back(SubnetServiceMessage::EnrRemove(Subnet::SyncCommittee(
subnet_id,
)));
}
}
impl<T: BeaconChainTypes> Stream for SyncCommitteeService<T> {
type Item = SubnetServiceMessage;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
// update the waker if needed
if let Some(waker) = &self.waker {
if waker.will_wake(cx.waker()) {
self.waker = Some(cx.waker().clone());
}
} else {
self.waker = Some(cx.waker().clone());
}
// process any un-subscription events
match self.unsubscriptions.poll_next_unpin(cx) {
Poll::Ready(Some(Ok(exact_subnet))) => self.handle_unsubscriptions(exact_subnet),
Poll::Ready(Some(Err(e))) => {
error!(self.log, "Failed to check for subnet unsubscription times"; "error"=> e);
}
Poll::Ready(None) | Poll::Pending => {}
}
// process any generated events
if let Some(event) = self.events.pop_front() {
return Poll::Ready(Some(event));
}
Poll::Pending
}
}