prysm-pulse/beacon-chain/forkchoice/doubly-linked-tree/forkchoice.go

640 lines
20 KiB
Go

package doublylinkedtree
import (
"context"
"fmt"
"time"
"github.com/pkg/errors"
"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
"github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice"
forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
"github.com/prysmaticlabs/prysm/v4/config/params"
"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
v1 "github.com/prysmaticlabs/prysm/v4/proto/eth/v1"
ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
"github.com/prysmaticlabs/prysm/v4/runtime/version"
"github.com/prysmaticlabs/prysm/v4/time/slots"
"github.com/sirupsen/logrus"
"go.opencensus.io/trace"
)
// New initializes a new fork choice store.
func New() *ForkChoice {
s := &Store{
justifiedCheckpoint: &forkchoicetypes.Checkpoint{},
unrealizedJustifiedCheckpoint: &forkchoicetypes.Checkpoint{},
unrealizedFinalizedCheckpoint: &forkchoicetypes.Checkpoint{},
prevJustifiedCheckpoint: &forkchoicetypes.Checkpoint{},
finalizedCheckpoint: &forkchoicetypes.Checkpoint{},
proposerBoostRoot: [32]byte{},
nodeByRoot: make(map[[fieldparams.RootLength]byte]*Node),
nodeByPayload: make(map[[fieldparams.RootLength]byte]*Node),
slashedIndices: make(map[primitives.ValidatorIndex]bool),
receivedBlocksLastEpoch: [fieldparams.SlotsPerEpoch]primitives.Slot{},
}
b := make([]uint64, 0)
v := make([]Vote, 0)
return &ForkChoice{store: s, balances: b, votes: v}
}
// NodeCount returns the current number of nodes in the Store.
func (f *ForkChoice) NodeCount() int {
return len(f.store.nodeByRoot)
}
// Head returns the head root from fork choice store.
// It firsts computes validator's balance changes then recalculates block tree from leaves to root.
func (f *ForkChoice) Head(
ctx context.Context,
) ([32]byte, error) {
ctx, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.Head")
defer span.End()
calledHeadCount.Inc()
if err := f.updateBalances(); err != nil {
return [32]byte{}, errors.Wrap(err, "could not update balances")
}
if err := f.applyProposerBoostScore(); err != nil {
return [32]byte{}, errors.Wrap(err, "could not apply proposer boost score")
}
if err := f.store.treeRootNode.applyWeightChanges(ctx); err != nil {
return [32]byte{}, errors.Wrap(err, "could not apply weight changes")
}
jc := f.JustifiedCheckpoint()
fc := f.FinalizedCheckpoint()
currentEpoch := slots.EpochsSinceGenesis(time.Unix(int64(f.store.genesisTime), 0))
if err := f.store.treeRootNode.updateBestDescendant(ctx, jc.Epoch, fc.Epoch, currentEpoch); err != nil {
return [32]byte{}, errors.Wrap(err, "could not update best descendant")
}
return f.store.head(ctx)
}
// ProcessAttestation processes attestation for vote accounting, it iterates around validator indices
// and update their votes accordingly.
func (f *ForkChoice) ProcessAttestation(ctx context.Context, validatorIndices []uint64, blockRoot [32]byte, targetEpoch primitives.Epoch) {
_, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.ProcessAttestation")
defer span.End()
for _, index := range validatorIndices {
// Validator indices will grow the vote cache.
for index >= uint64(len(f.votes)) {
f.votes = append(f.votes, Vote{currentRoot: params.BeaconConfig().ZeroHash, nextRoot: params.BeaconConfig().ZeroHash})
}
// Newly allocated vote if the root fields are untouched.
newVote := f.votes[index].nextRoot == params.BeaconConfig().ZeroHash &&
f.votes[index].currentRoot == params.BeaconConfig().ZeroHash
// Vote gets updated if it's newly allocated or high target epoch.
if newVote || targetEpoch > f.votes[index].nextEpoch {
f.votes[index].nextEpoch = targetEpoch
f.votes[index].nextRoot = blockRoot
}
}
processedAttestationCount.Inc()
}
// InsertNode processes a new block by inserting it to the fork choice store.
func (f *ForkChoice) InsertNode(ctx context.Context, state state.BeaconState, root [32]byte) error {
ctx, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.InsertNode")
defer span.End()
slot := state.Slot()
bh := state.LatestBlockHeader()
if bh == nil {
return errNilBlockHeader
}
parentRoot := bytesutil.ToBytes32(bh.ParentRoot)
var payloadHash [32]byte
if state.Version() >= version.Bellatrix {
ph, err := state.LatestExecutionPayloadHeader()
if err != nil {
return err
}
if ph != nil {
copy(payloadHash[:], ph.BlockHash())
}
}
jc := state.CurrentJustifiedCheckpoint()
if jc == nil {
return errInvalidNilCheckpoint
}
justifiedEpoch := jc.Epoch
fc := state.FinalizedCheckpoint()
if fc == nil {
return errInvalidNilCheckpoint
}
finalizedEpoch := fc.Epoch
node, err := f.store.insert(ctx, slot, root, parentRoot, payloadHash, justifiedEpoch, finalizedEpoch)
if err != nil {
return err
}
jc, fc = f.store.pullTips(state, node, jc, fc)
return f.updateCheckpoints(ctx, jc, fc)
}
// updateCheckpoints update the checkpoints when inserting a new node.
func (f *ForkChoice) updateCheckpoints(ctx context.Context, jc, fc *ethpb.Checkpoint) error {
if jc.Epoch > f.store.justifiedCheckpoint.Epoch {
f.store.prevJustifiedCheckpoint = f.store.justifiedCheckpoint
jcRoot := bytesutil.ToBytes32(jc.Root)
f.store.justifiedCheckpoint = &forkchoicetypes.Checkpoint{Epoch: jc.Epoch, Root: jcRoot}
if err := f.updateJustifiedBalances(ctx, jcRoot); err != nil {
return errors.Wrap(err, "could not update justified balances")
}
}
// Update finalization
if fc.Epoch <= f.store.finalizedCheckpoint.Epoch {
return nil
}
f.store.finalizedCheckpoint = &forkchoicetypes.Checkpoint{Epoch: fc.Epoch,
Root: bytesutil.ToBytes32(fc.Root)}
return f.store.prune(ctx)
}
// HasNode returns true if the node exists in fork choice store,
// false else wise.
func (f *ForkChoice) HasNode(root [32]byte) bool {
_, ok := f.store.nodeByRoot[root]
return ok
}
// IsCanonical returns true if the given root is part of the canonical chain.
func (f *ForkChoice) IsCanonical(root [32]byte) bool {
node, ok := f.store.nodeByRoot[root]
if !ok || node == nil {
return false
}
if node.bestDescendant == nil {
if f.store.headNode.bestDescendant == nil {
return node == f.store.headNode
}
return node == f.store.headNode.bestDescendant
}
if f.store.headNode.bestDescendant == nil {
return node.bestDescendant == f.store.headNode
}
return node.bestDescendant == f.store.headNode.bestDescendant
}
// IsOptimistic returns true if the given root has been optimistically synced.
func (f *ForkChoice) IsOptimistic(root [32]byte) (bool, error) {
if f.store.allTipsAreInvalid {
return true, nil
}
node, ok := f.store.nodeByRoot[root]
if !ok || node == nil {
return true, ErrNilNode
}
return node.optimistic, nil
}
// AncestorRoot returns the ancestor root of input block root at a given slot.
func (f *ForkChoice) AncestorRoot(ctx context.Context, root [32]byte, slot primitives.Slot) ([32]byte, error) {
ctx, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.AncestorRoot")
defer span.End()
node, ok := f.store.nodeByRoot[root]
if !ok || node == nil {
return [32]byte{}, errors.Wrap(ErrNilNode, "could not determine ancestor root")
}
n := node
for n != nil && n.slot > slot {
if ctx.Err() != nil {
return [32]byte{}, ctx.Err()
}
n = n.parent
}
if n == nil {
return [32]byte{}, errors.Wrap(ErrNilNode, "could not determine ancestor root")
}
return n.root, nil
}
// IsViableForCheckpoint returns whether the root passed is a checkpoint root for any
// known chain in forkchoice.
func (f *ForkChoice) IsViableForCheckpoint(cp *forkchoicetypes.Checkpoint) (bool, error) {
node, ok := f.store.nodeByRoot[cp.Root]
if !ok || node == nil {
return false, nil
}
epochStart, err := slots.EpochStart(cp.Epoch)
if err != nil {
return false, err
}
if node.slot > epochStart {
return false, nil
}
if len(node.children) == 0 {
return true, nil
}
if node.slot == epochStart {
return true, nil
}
nodeEpoch := slots.ToEpoch(node.slot)
if nodeEpoch >= cp.Epoch {
return false, nil
}
for _, child := range node.children {
if child.slot > epochStart {
return true, nil
}
}
return false, nil
}
// updateBalances updates the balances that directly voted for each block taking into account the
// validators' latest votes.
func (f *ForkChoice) updateBalances() error {
newBalances := f.justifiedBalances
zHash := params.BeaconConfig().ZeroHash
for index, vote := range f.votes {
// Skip if validator has been slashed
if f.store.slashedIndices[primitives.ValidatorIndex(index)] {
continue
}
// Skip if validator has never voted for current root and next root (i.e. if the
// votes are zero hash aka genesis block), there's nothing to compute.
if vote.currentRoot == zHash && vote.nextRoot == zHash {
continue
}
oldBalance := uint64(0)
newBalance := uint64(0)
// If the validator index did not exist in `f.balances` or
// `newBalances` list above, the balance is just 0.
if index < len(f.balances) {
oldBalance = f.balances[index]
}
if index < len(newBalances) {
newBalance = newBalances[index]
}
// Update only if the validator's balance or vote has changed.
if vote.currentRoot != vote.nextRoot || oldBalance != newBalance {
// Ignore the vote if the root is not in fork choice
// store, that means we have not seen the block before.
nextNode, ok := f.store.nodeByRoot[vote.nextRoot]
if ok && vote.nextRoot != zHash {
// Protection against nil node
if nextNode == nil {
return errors.Wrap(ErrNilNode, "could not update balances")
}
nextNode.balance += newBalance
}
currentNode, ok := f.store.nodeByRoot[vote.currentRoot]
if ok && vote.currentRoot != zHash {
// Protection against nil node
if currentNode == nil {
return errors.Wrap(ErrNilNode, "could not update balances")
}
if currentNode.balance < oldBalance {
log.WithFields(logrus.Fields{
"nodeRoot": fmt.Sprintf("%#x", bytesutil.Trunc(vote.currentRoot[:])),
"oldBalance": oldBalance,
"nodeBalance": currentNode.balance,
"nodeWeight": currentNode.weight,
"proposerBoostRoot": fmt.Sprintf("%#x", bytesutil.Trunc(f.store.proposerBoostRoot[:])),
"previousProposerBoostRoot": fmt.Sprintf("%#x", bytesutil.Trunc(f.store.previousProposerBoostRoot[:])),
"previousProposerBoostScore": f.store.previousProposerBoostScore,
}).Warning("node with invalid balance, setting it to zero")
currentNode.balance = 0
} else {
currentNode.balance -= oldBalance
}
}
}
// Rotate the validator vote.
f.votes[index].currentRoot = vote.nextRoot
}
f.balances = newBalances
return nil
}
// Tips returns a list of possible heads from fork choice store, it returns the
// roots and the slots of the leaf nodes.
func (f *ForkChoice) Tips() ([][32]byte, []primitives.Slot) {
return f.store.tips()
}
// ProposerBoost returns the proposerBoost of the store
func (f *ForkChoice) ProposerBoost() [fieldparams.RootLength]byte {
return f.store.proposerBoost()
}
// SetOptimisticToValid sets the node with the given root as a fully validated node
func (f *ForkChoice) SetOptimisticToValid(ctx context.Context, root [fieldparams.RootLength]byte) error {
node, ok := f.store.nodeByRoot[root]
if !ok || node == nil {
return errors.Wrap(ErrNilNode, "could not set node to valid")
}
return node.setNodeAndParentValidated(ctx)
}
// PreviousJustifiedCheckpoint of fork choice store.
func (f *ForkChoice) PreviousJustifiedCheckpoint() *forkchoicetypes.Checkpoint {
return f.store.prevJustifiedCheckpoint
}
// JustifiedCheckpoint of fork choice store.
func (f *ForkChoice) JustifiedCheckpoint() *forkchoicetypes.Checkpoint {
return f.store.justifiedCheckpoint
}
// FinalizedCheckpoint of fork choice store.
func (f *ForkChoice) FinalizedCheckpoint() *forkchoicetypes.Checkpoint {
return f.store.finalizedCheckpoint
}
// SetOptimisticToInvalid removes a block with an invalid execution payload from fork choice store
func (f *ForkChoice) SetOptimisticToInvalid(ctx context.Context, root, parentRoot, payloadHash [fieldparams.RootLength]byte) ([][32]byte, error) {
return f.store.setOptimisticToInvalid(ctx, root, parentRoot, payloadHash)
}
// InsertSlashedIndex adds the given slashed validator index to the
// store-tracked list. Votes from these validators are not accounted for
// in forkchoice.
func (f *ForkChoice) InsertSlashedIndex(_ context.Context, index primitives.ValidatorIndex) {
// return early if the index was already included:
if f.store.slashedIndices[index] {
return
}
f.store.slashedIndices[index] = true
// Subtract last vote from this equivocating validator
if index >= primitives.ValidatorIndex(len(f.balances)) {
return
}
if index >= primitives.ValidatorIndex(len(f.votes)) {
return
}
node, ok := f.store.nodeByRoot[f.votes[index].currentRoot]
if !ok || node == nil {
return
}
if node.balance < f.balances[index] {
node.balance = 0
} else {
node.balance -= f.balances[index]
}
}
// UpdateJustifiedCheckpoint sets the justified checkpoint to the given one
func (f *ForkChoice) UpdateJustifiedCheckpoint(ctx context.Context, jc *forkchoicetypes.Checkpoint) error {
if jc == nil {
return errInvalidNilCheckpoint
}
f.store.prevJustifiedCheckpoint = f.store.justifiedCheckpoint
f.store.justifiedCheckpoint = jc
if err := f.updateJustifiedBalances(ctx, jc.Root); err != nil {
return errors.Wrap(err, "could not update justified balances")
}
return nil
}
// UpdateFinalizedCheckpoint sets the finalized checkpoint to the given one
func (f *ForkChoice) UpdateFinalizedCheckpoint(fc *forkchoicetypes.Checkpoint) error {
if fc == nil {
return errInvalidNilCheckpoint
}
f.store.finalizedCheckpoint = fc
return nil
}
// CommonAncestor returns the common ancestor root and slot between the two block roots r1 and r2.
func (f *ForkChoice) CommonAncestor(ctx context.Context, r1 [32]byte, r2 [32]byte) ([32]byte, primitives.Slot, error) {
ctx, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.CommonAncestorRoot")
defer span.End()
n1, ok := f.store.nodeByRoot[r1]
if !ok || n1 == nil {
return [32]byte{}, 0, forkchoice.ErrUnknownCommonAncestor
}
// Do nothing if the input roots are the same.
if r1 == r2 {
return r1, n1.slot, nil
}
n2, ok := f.store.nodeByRoot[r2]
if !ok || n2 == nil {
return [32]byte{}, 0, forkchoice.ErrUnknownCommonAncestor
}
for {
if ctx.Err() != nil {
return [32]byte{}, 0, ctx.Err()
}
if n1.slot > n2.slot {
n1 = n1.parent
// Reaches the end of the tree and unable to find common ancestor.
// This should not happen at runtime as the finalized
// node has to be a common ancestor
if n1 == nil {
return [32]byte{}, 0, forkchoice.ErrUnknownCommonAncestor
}
} else {
n2 = n2.parent
// Reaches the end of the tree and unable to find common ancestor.
if n2 == nil {
return [32]byte{}, 0, forkchoice.ErrUnknownCommonAncestor
}
}
if n1 == n2 {
return n1.root, n1.slot, nil
}
}
}
// InsertChain inserts all nodes corresponding to blocks in the slice
// `blocks`. This slice must be ordered from child to parent. It includes all
// blocks **except** the first one (that is the one with the highest slot
// number). All blocks are assumed to be a strict chain
// where blocks[i].Parent = blocks[i+1]. Also we assume that the parent of the
// last block in this list is already included in forkchoice store.
func (f *ForkChoice) InsertChain(ctx context.Context, chain []*forkchoicetypes.BlockAndCheckpoints) error {
if len(chain) == 0 {
return nil
}
for i := len(chain) - 1; i > 0; i-- {
b := chain[i].Block
r := chain[i-1].Block.ParentRoot()
parentRoot := b.ParentRoot()
payloadHash, err := blocks.GetBlockPayloadHash(b)
if err != nil {
return err
}
if _, err := f.store.insert(ctx,
b.Slot(), r, parentRoot, payloadHash,
chain[i].JustifiedCheckpoint.Epoch, chain[i].FinalizedCheckpoint.Epoch); err != nil {
return err
}
if err := f.updateCheckpoints(ctx, chain[i].JustifiedCheckpoint, chain[i].FinalizedCheckpoint); err != nil {
return err
}
}
return nil
}
// SetGenesisTime sets the genesisTime tracked by forkchoice
func (f *ForkChoice) SetGenesisTime(genesisTime uint64) {
f.store.genesisTime = genesisTime
}
// SetOriginRoot sets the genesis block root
func (f *ForkChoice) SetOriginRoot(root [32]byte) {
f.store.originRoot = root
}
// CachedHeadRoot returns the last cached head root
func (f *ForkChoice) CachedHeadRoot() [32]byte {
node := f.store.headNode
if node == nil {
return [32]byte{}
}
return f.store.headNode.root
}
// FinalizedPayloadBlockHash returns the hash of the payload at the finalized checkpoint
func (f *ForkChoice) FinalizedPayloadBlockHash() [32]byte {
root := f.FinalizedCheckpoint().Root
node, ok := f.store.nodeByRoot[root]
if !ok || node == nil {
// This should not happen
return [32]byte{}
}
return node.payloadHash
}
// JustifiedPayloadBlockHash returns the hash of the payload at the justified checkpoint
func (f *ForkChoice) JustifiedPayloadBlockHash() [32]byte {
root := f.JustifiedCheckpoint().Root
node, ok := f.store.nodeByRoot[root]
if !ok || node == nil {
// This should not happen
return [32]byte{}
}
return node.payloadHash
}
// UnrealizedJustifiedPayloadBlockHash returns the hash of the payload at the unrealized justified checkpoint
func (f *ForkChoice) UnrealizedJustifiedPayloadBlockHash() [32]byte {
root := f.store.unrealizedJustifiedCheckpoint.Root
node, ok := f.store.nodeByRoot[root]
if !ok || node == nil {
// This should not happen
return [32]byte{}
}
return node.payloadHash
}
// ForkChoiceDump returns a full dump of forkchoice.
func (f *ForkChoice) ForkChoiceDump(ctx context.Context) (*v1.ForkChoiceDump, error) {
jc := &v1.Checkpoint{
Epoch: f.store.justifiedCheckpoint.Epoch,
Root: f.store.justifiedCheckpoint.Root[:],
}
ujc := &v1.Checkpoint{
Epoch: f.store.unrealizedJustifiedCheckpoint.Epoch,
Root: f.store.unrealizedJustifiedCheckpoint.Root[:],
}
fc := &v1.Checkpoint{
Epoch: f.store.finalizedCheckpoint.Epoch,
Root: f.store.finalizedCheckpoint.Root[:],
}
ufc := &v1.Checkpoint{
Epoch: f.store.unrealizedFinalizedCheckpoint.Epoch,
Root: f.store.unrealizedFinalizedCheckpoint.Root[:],
}
nodes := make([]*v1.ForkChoiceNode, 0, f.NodeCount())
var err error
if f.store.treeRootNode != nil {
nodes, err = f.store.treeRootNode.nodeTreeDump(ctx, nodes)
if err != nil {
return nil, err
}
}
var headRoot [32]byte
if f.store.headNode != nil {
headRoot = f.store.headNode.root
}
resp := &v1.ForkChoiceDump{
JustifiedCheckpoint: jc,
UnrealizedJustifiedCheckpoint: ujc,
FinalizedCheckpoint: fc,
UnrealizedFinalizedCheckpoint: ufc,
ProposerBoostRoot: f.store.proposerBoostRoot[:],
PreviousProposerBoostRoot: f.store.previousProposerBoostRoot[:],
HeadRoot: headRoot[:],
ForkChoiceNodes: nodes,
}
return resp, nil
}
// SetBalancesByRooter sets the balanceByRoot handler in forkchoice
func (f *ForkChoice) SetBalancesByRooter(handler forkchoice.BalancesByRooter) {
f.balancesByRoot = handler
}
// Weight returns the weight of the given root if found on the store
func (f *ForkChoice) Weight(root [32]byte) (uint64, error) {
n, ok := f.store.nodeByRoot[root]
if !ok || n == nil {
return 0, ErrNilNode
}
return n.weight, nil
}
// updateJustifiedBalances updates the validators balances on the justified checkpoint pointed by root.
func (f *ForkChoice) updateJustifiedBalances(ctx context.Context, root [32]byte) error {
balances, err := f.balancesByRoot(ctx, root)
if err != nil {
return errors.Wrap(err, "could not get justified balances")
}
f.justifiedBalances = balances
f.store.committeeWeight = 0
f.numActiveValidators = 0
for _, val := range balances {
if val > 0 {
f.store.committeeWeight += val
f.numActiveValidators++
}
}
f.store.committeeWeight /= uint64(params.BeaconConfig().SlotsPerEpoch)
return nil
}
// Slot returns the slot of the given root if it's known to forkchoice
func (f *ForkChoice) Slot(root [32]byte) (primitives.Slot, error) {
n, ok := f.store.nodeByRoot[root]
if !ok || n == nil {
return 0, ErrNilNode
}
return n.slot, nil
}