go-ethereum/eth/downloader/whitelist/service.go
Evgeny Danienko 01117acbcc fmt
2022-05-19 14:41:49 +03:00

116 lines
3.9 KiB
Go

package whitelist
import (
"errors"
"fmt"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/log"
)
// Checkpoint whitelist
type Service struct {
m sync.Mutex
checkpointWhitelist map[uint64]common.Hash // Checkpoint whitelist, populated by reaching out to heimdall
checkpointOrder []uint64 // Checkpoint order, populated by reaching out to heimdall
maxCapacity uint
}
func NewService(maxCapacity uint) *Service {
return &Service{
checkpointWhitelist: make(map[uint64]common.Hash),
checkpointOrder: []uint64{},
maxCapacity: maxCapacity,
}
}
var (
ErrCheckpointMismatch = errors.New("checkpoint mismatch")
ErrNoRemoteCheckoint = errors.New("remote peer doesn't have a checkoint")
)
// IsValidChain checks if the chain we're about to receive from this peer is valid or not
// in terms of reorgs. We won't reorg beyond the last bor checkpoint submitted to mainchain.
func (w *Service) IsValidChain(remoteHeader *types.Header, fetchHeadersByNumber func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error) {
// We want to validate the chain by comparing the last checkpointed block
// we're storing in `checkpointWhitelist` with the peer's block.
// Check for availaibility of the last checkpointed block.
// This can be also be empty if our heimdall is not responding
// or we're running without it.
if len(w.checkpointWhitelist) == 0 {
// worst case, we don't have the checkpoints in memory
return true, nil
}
// Fetch the last checkpoint entry
lastCheckpointBlockNum := w.checkpointOrder[len(w.checkpointOrder)-1]
lastCheckpointBlockHash := w.checkpointWhitelist[lastCheckpointBlockNum]
// todo: we can extract this as an interface and mock as well or just test IsValidChain in isolation from downloader passing fake fetchHeadersByNumber functions
headers, hashes, err := fetchHeadersByNumber(lastCheckpointBlockNum, 1, 0, false)
if err != nil {
return false, fmt.Errorf("%w: last checkpoint %d, err %v", ErrNoRemoteCheckoint, lastCheckpointBlockNum, err)
}
if len(headers) == 0 {
return true, fmt.Errorf("%w: last checkpoint %d", ErrNoRemoteCheckoint, lastCheckpointBlockNum)
}
reqBlockNum := headers[0].Number.Uint64()
reqBlockHash := hashes[0]
// Check against the checkpointed blocks
if reqBlockNum == lastCheckpointBlockNum && reqBlockHash == lastCheckpointBlockHash {
return true, nil
}
return false, ErrCheckpointMismatch
}
func (w *Service) ProcessCheckpoint(endBlockNum uint64, endBlockHash common.Hash) {
w.m.Lock()
defer w.m.Unlock()
w.enqueueCheckpointWhitelist(endBlockNum, endBlockHash)
// If size of checkpoint whitelist map is greater than 10, remove the oldest entry.
if w.length() > int(w.maxCapacity) {
w.dequeueCheckpointWhitelist()
}
}
// PurgeWhitelistMap purges data from checkpoint whitelist map
func (w *Service) purgeWhitelistMap() error {
for k := range w.checkpointWhitelist {
delete(w.checkpointWhitelist, k)
}
return nil
}
// EnqueueWhitelistBlock enqueues blockNumber, blockHash to the checkpoint whitelist map
func (w *Service) enqueueCheckpointWhitelist(key uint64, val common.Hash) {
if _, ok := w.checkpointWhitelist[key]; !ok {
log.Debug("Enqueing new checkpoint whitelist", "block number", key, "block hash", val)
w.checkpointWhitelist[key] = val
w.checkpointOrder = append(w.checkpointOrder, key)
}
}
// DequeueWhitelistBlock dequeues block, blockhash from the checkpoint whitelist map
func (w *Service) dequeueCheckpointWhitelist() {
if len(w.checkpointOrder) > 0 {
log.Debug("Dequeing checkpoint whitelist", "block number", w.checkpointOrder[0], "block hash", w.checkpointWhitelist[w.checkpointOrder[0]])
delete(w.checkpointWhitelist, w.checkpointOrder[0])
w.checkpointOrder = w.checkpointOrder[1:]
}
}
// length returns the len of the whitelist.
func (w *Service) length() int {
return len(w.checkpointWhitelist)
}