Merge branch 'develop' into refcell/feat/txcreation

.changeset/fresh-pots-move.md

+---
+'@eth-optimism/batch-submitter-service': patch
+---
+
+Allow deposit only batches

CONTRIBUTING.md

@@ -66,6 +66,7 @@ You'll need the following:
 * [Yarn](https://classic.yarnpkg.com/en/docs/install)
 * [Docker](https://docs.docker.com/get-docker/)
 * [Docker Compose](https://docs.docker.com/compose/install/)
+* [Go](https://go.dev/dl/)
 * [Foundry](https://getfoundry.sh)
 
 ### Setup

batch-submitter/drivers/sequencer/batch_test.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/ethereum-optimism/optimism/batch-submitter/drivers/sequencer"
 	l2common "github.com/ethereum-optimism/optimism/l2geth/common"
+	"github.com/ethereum-optimism/optimism/l2geth/core/types"
 	l2types "github.com/ethereum-optimism/optimism/l2geth/core/types"
 	"github.com/stretchr/testify/require"
 )
@@ -47,3 +48,76 @@ func TestBatchElementFromBlock(t *testing.T) {
 	require.False(t, element.IsSequencerTx())
 	require.Nil(t, element.Tx)
 }
+
+func TestGenSequencerParams(t *testing.T) {
+	tx := types.NewTransaction(0, l2common.Address{}, big.NewInt(0), 0, big.NewInt(0), []byte{})
+
+	shouldStartAtElement := uint64(1)
+	blockOffset := uint64(1)
+	batches := []sequencer.BatchElement{
+		{Timestamp: 1, BlockNumber: 1},
+		{Timestamp: 1, BlockNumber: 1, Tx: sequencer.NewCachedTx(tx)},
+	}
+
+	params, err := sequencer.GenSequencerBatchParams(shouldStartAtElement, blockOffset, batches)
+	require.NoError(t, err)
+
+	require.Equal(t, uint64(0), params.ShouldStartAtElement)
+	require.Equal(t, uint64(len(batches)), params.TotalElementsToAppend)
+	require.Equal(t, len(batches), len(params.Contexts))
+	// There is only 1 sequencer tx
+	require.Equal(t, 1, len(params.Txs))
+
+	// There are 2 contexts
+	// The first context contains the deposit
+	context1 := params.Contexts[0]
+	require.Equal(t, uint64(0), context1.NumSequencedTxs)
+	require.Equal(t, uint64(1), context1.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(1), context1.Timestamp)
+	require.Equal(t, uint64(1), context1.BlockNumber)
+
+	// The second context contains the sequencer tx
+	context2 := params.Contexts[1]
+	require.Equal(t, uint64(1), context2.NumSequencedTxs)
+	require.Equal(t, uint64(0), context2.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(1), context2.Timestamp)
+	require.Equal(t, uint64(1), context2.BlockNumber)
+}
+
+func TestGenSequencerParamsOnlyDeposits(t *testing.T) {
+	shouldStartAtElement := uint64(1)
+	blockOffset := uint64(1)
+	batches := []sequencer.BatchElement{
+		{Timestamp: 1, BlockNumber: 1},
+		{Timestamp: 1, BlockNumber: 1},
+		{Timestamp: 2, BlockNumber: 2},
+	}
+
+	params, err := sequencer.GenSequencerBatchParams(shouldStartAtElement, blockOffset, batches)
+	require.NoError(t, err)
+
+	// The batches will pack deposits into the same context when their
+	// timestamps and blocknumbers are the same
+	require.Equal(t, uint64(0), params.ShouldStartAtElement)
+	require.Equal(t, uint64(len(batches)), params.TotalElementsToAppend)
+	// 2 deposits have the same timestamp + blocknumber, they go in the
+	// same context. 1 deposit has a different timestamp + blocknumber,
+	// it goes into a different context. Therefore there are 2 contexts
+	require.Equal(t, 2, len(params.Contexts))
+	// No sequencer txs
+	require.Equal(t, 0, len(params.Txs))
+
+	// There are 2 contexts
+	// The first context contains the deposit
+	context1 := params.Contexts[0]
+	require.Equal(t, uint64(0), context1.NumSequencedTxs)
+	require.Equal(t, uint64(2), context1.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(1), context1.Timestamp)
+	require.Equal(t, uint64(1), context1.BlockNumber)
+
+	context2 := params.Contexts[1]
+	require.Equal(t, uint64(0), context2.NumSequencedTxs)
+	require.Equal(t, uint64(1), context2.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(2), context2.Timestamp)
+	require.Equal(t, uint64(2), context2.BlockNumber)
+}

batch-submitter/drivers/sequencer/encoding.go

@@ -222,11 +222,6 @@ func (p *AppendSequencerBatchParams) Write(
 		return ErrMalformedBatch
 	}
 
-	// There must be transactions if there are contexts
-	if len(p.Txs) == 0 && len(p.Contexts) != 0 {
-		return ErrMalformedBatch
-	}
-
 	// copy the contexts as to not malleate the struct
 	// when it is a typed batch
 	contexts := make([]BatchContext, 0, len(p.Contexts)+1)
@@ -361,9 +356,6 @@ func (p *AppendSequencerBatchParams) Read(r io.Reader) error {
 			if len(p.Contexts) == 0 && len(p.Txs) != 0 {
 				return ErrMalformedBatch
 			}
-			if len(p.Txs) == 0 && len(p.Contexts) != 0 {
-				return ErrMalformedBatch
-			}
 			return closeReader()
 		} else if err != nil {
 			return err

batch-submitter/drivers/sequencer/testdata/valid_append_sequencer_batch_params.json

@@ -46,7 +46,7 @@
         }
       ],
       "txs": [],
-      "error": true
+      "error": false
     },
     {
       "name": "multiple-contexts-no-txs",
@@ -80,7 +80,7 @@
         }
       ],
       "txs": [],
-      "error": true
+      "error": false
     },
     {
       "name": "complex",

docs/op-stack/src/docs/build/getting-started.md

@@ -201,7 +201,7 @@ Once you’ve built both repositories, you’ll need head back to the Optimism M
     - Replace `"BATCHER"` with the address of the Batcher account you generated earlier.
     - Replace `"SEQUENCER"` with the address of the Sequencer account you generated earlier.
     - Replace `"BLOCKHASH"` with the blockhash you got from the `cast` command.
-    - Replace `"TIMESTAMP"` with the timestamp you got from the `cast` command. Note that although all the other fields are strings, this field is a number! Don’t include the quotation marks.
+    - Replace `TIMESTAMP` with the timestamp you got from the `cast` command. Note that although all the other fields are strings, this field is a number! Don’t include the quotation marks.
 
 ## Deploy the L1 contracts
 
@@ -578,4 +578,4 @@ To add nodes to the rollup, you need to initialize `op-node` and `op-geth`, simi
 
 ## What’s next?
 
-You can use this rollup the same way you’d use any other test blockchain. Once the superchain is available, this blockchain should be able to join the test version. Alternatively, you could [modify the blockchain in various ways](./hacks.md). **Please note that OP Stack Hacks are unofficial and are not explicitly supported by the OP Stack.** You will not be able to receive significant developer support for any modifications you make to the OP Stack.
\ No newline at end of file
+You can use this rollup the same way you’d use any other test blockchain. Once the superchain is available, this blockchain should be able to join the test version. Alternatively, you could [modify the blockchain in various ways](./hacks.md). **Please note that OP Stack Hacks are unofficial and are not explicitly supported by the OP Stack.** You will not be able to receive significant developer support for any modifications you make to the OP Stack.

op-batcher/metrics/metrics.go

@@ -185,7 +185,7 @@ func (m *Metrics) RecordLatestL1Block(l1ref eth.L1BlockRef) {
 	m.RecordL1Ref("latest", l1ref)
 }
 
-// RecordL2BlockLoaded should be called when a new L2 block was loaded into the
+// RecordL2BlocksLoaded should be called when a new L2 block was loaded into the
 // channel manager (but not processed yet).
 func (m *Metrics) RecordL2BlocksLoaded(l2ref eth.L2BlockRef) {
 	m.RecordL2Ref(StageLoaded, l2ref)

op-e2e/actions/l2_proposer.go

@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/ethereum-optimism/optimism/op-node/sources"
+	"github.com/ethereum-optimism/optimism/op-proposer/metrics"
 	"github.com/ethereum-optimism/optimism/op-proposer/proposer"
 	opcrypto "github.com/ethereum-optimism/optimism/op-service/crypto"
 	"github.com/ethereum-optimism/optimism/op-service/txmgr"
@@ -61,7 +62,7 @@ func NewL2Proposer(t Testing, log log.Logger, cfg *ProposerCfg, l1 *ethclient.Cl
 		SignerFnFactory:   signer,
 	}
 
-	dr, err := proposer.NewL2OutputSubmitter(proposerCfg, log)
+	dr, err := proposer.NewL2OutputSubmitter(proposerCfg, log, metrics.NoopMetrics)
 	require.NoError(t, err)
 
 	return &L2Proposer{

op-e2e/migration_test.go

@@ -15,6 +15,7 @@ import (
 	batchermetrics "github.com/ethereum-optimism/optimism/op-batcher/metrics"
 	"github.com/ethereum-optimism/optimism/op-node/chaincfg"
 	"github.com/ethereum-optimism/optimism/op-node/sources"
+	proposermetrics "github.com/ethereum-optimism/optimism/op-proposer/metrics"
 	l2os "github.com/ethereum-optimism/optimism/op-proposer/proposer"
 	oplog "github.com/ethereum-optimism/optimism/op-service/log"
 
@@ -277,6 +278,7 @@ func TestMigration(t *testing.T) {
 			L2EngineAddr:      gethNode.HTTPAuthEndpoint(),
 			L2EngineJWTSecret: testingJWTSecret,
 		},
+		L2Sync: &node.PreparedL2SyncEndpoint{Client: nil, TrustRPC: false},
 		Driver: driver.Config{
 			VerifierConfDepth:  0,
 			SequencerConfDepth: 0,
@@ -364,7 +366,7 @@ func TestMigration(t *testing.T) {
 			Format: "text",
 		},
 		PrivateKey: hexPriv(secrets.Proposer),
-	}, lgr.New("module", "proposer"))
+	}, lgr.New("module", "proposer"), proposermetrics.NoopMetrics)
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		proposer.Stop()

op-e2e/setup.go

@@ -37,6 +37,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/rollup/driver"
 	"github.com/ethereum-optimism/optimism/op-node/sources"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
+	proposermetrics "github.com/ethereum-optimism/optimism/op-proposer/metrics"
 	l2os "github.com/ethereum-optimism/optimism/op-proposer/proposer"
 	oplog "github.com/ethereum-optimism/optimism/op-service/log"
 )
@@ -193,6 +194,9 @@ type SystemConfig struct {
 
 	// If the proposer can make proposals for L2 blocks derived from L1 blocks which are not finalized on L1 yet.
 	NonFinalizedProposals bool
+
+	// Explicitly disable batcher, for tests that rely on unsafe L2 payloads
+	DisableBatcher bool
 }
 
 type System struct {
@@ -417,6 +421,10 @@ func (cfg SystemConfig) Start(_opts ...SystemConfigOption) (*System, error) {
 			L2EngineAddr:      l2EndpointConfig,
 			L2EngineJWTSecret: cfg.JWTSecret,
 		}
+		rollupCfg.L2Sync = &rollupNode.PreparedL2SyncEndpoint{
+			Client:   nil,
+			TrustRPC: false,
+		}
 	}
 
 	// Geth Clients
@@ -572,7 +580,7 @@ func (cfg SystemConfig) Start(_opts ...SystemConfigOption) (*System, error) {
 			Format: "text",
 		},
 		PrivateKey: hexPriv(cfg.Secrets.Proposer),
-	}, sys.cfg.Loggers["proposer"])
+	}, sys.cfg.Loggers["proposer"], proposermetrics.NoopMetrics)
 	if err != nil {
 		return nil, fmt.Errorf("unable to setup l2 output submitter: %w", err)
 	}
@@ -609,8 +617,11 @@ func (cfg SystemConfig) Start(_opts ...SystemConfigOption) (*System, error) {
 		return nil, fmt.Errorf("failed to setup batch submitter: %w", err)
 	}
 
-	if err := sys.BatchSubmitter.Start(); err != nil {
-		return nil, fmt.Errorf("unable to start batch submitter: %w", err)
+	// Batcher may be enabled later
+	if !sys.cfg.DisableBatcher {
+		if err := sys.BatchSubmitter.Start(); err != nil {
+			return nil, fmt.Errorf("unable to start batch submitter: %w", err)
+		}
 	}
 
 	return sys, nil

op-e2e/system_test.go

@@ -649,7 +649,7 @@ func TestSystemMockP2P(t *testing.T) {
 	require.Contains(t, received, receiptVerif.BlockHash)
 }
 
-// TestSystemMockP2P sets up a L1 Geth node, a rollup node, and a L2 geth node and then confirms that
+// TestSystemRPCAltSync sets up a L1 Geth node, a rollup node, and a L2 geth node and then confirms that
 // the nodes can sync L2 blocks before they are confirmed on L1.
 //
 // Test steps:
@@ -660,24 +660,28 @@ func TestSystemMockP2P(t *testing.T) {
 // 6. Wait for the RPC sync method to grab the block from the sequencer over RPC and insert it into the verifier's unsafe chain.
 // 7. Wait for the verifier to sync the unsafe chain into the safe chain.
 // 8. Verify that the TX is included in the verifier's safe chain.
-func TestSystemMockAltSync(t *testing.T) {
+func TestSystemRPCAltSync(t *testing.T) {
 	parallel(t)
 	if !verboseGethNodes {
 		log.Root().SetHandler(log.DiscardHandler())
 	}
 
 	cfg := DefaultSystemConfig(t)
-	// slow down L1 blocks so we can see the L2 blocks arrive well before the L1 blocks do.
-	// Keep the seq window small so the L2 chain is started quick
-	cfg.DeployConfig.L1BlockTime = 10
+	// the default is nil, but this may change in the future.
+	// This test must ensure the blocks are not synced via Gossip, but instead via the alt RPC based sync.
+	cfg.P2PTopology = nil
+	// Disable batcher, so there will not be any L1 data to sync from
+	cfg.DisableBatcher = true
 
-	var published, received []common.Hash
+	var published, received []string
 	seqTracer, verifTracer := new(FnTracer), new(FnTracer)
+	// The sequencer still publishes the blocks to the tracer, even if they do not reach the network due to disabled P2P
 	seqTracer.OnPublishL2PayloadFn = func(ctx context.Context, payload *eth.ExecutionPayload) {
-		published = append(published, payload.BlockHash)
+		published = append(published, payload.ID().String())
 	}
+	// Blocks are now received via the RPC based alt-sync method
 	verifTracer.OnUnsafeL2PayloadFn = func(ctx context.Context, from peer.ID, payload *eth.ExecutionPayload) {
-		received = append(received, payload.BlockHash)
+		received = append(received, payload.ID().String())
 	}
 	cfg.Nodes["sequencer"].Tracer = seqTracer
 	cfg.Nodes["verifier"].Tracer = verifTracer
@@ -687,8 +691,8 @@ func TestSystemMockAltSync(t *testing.T) {
 		role: "sequencer",
 		action: func(sCfg *SystemConfig, system *System) {
 			rpc, _ := system.Nodes["sequencer"].Attach() // never errors
-			cfg.Nodes["verifier"].L2Sync = &rollupNode.L2SyncRPCConfig{
-				Rpc: client.NewBaseRPCClient(rpc),
+			cfg.Nodes["verifier"].L2Sync = &rollupNode.PreparedL2SyncEndpoint{
+				Client: client.NewBaseRPCClient(rpc),
 			}
 		},
 	})
@@ -726,7 +730,7 @@ func TestSystemMockAltSync(t *testing.T) {
 	require.Equal(t, receiptSeq, receiptVerif)
 
 	// Verify that the tx was received via RPC sync (P2P is disabled)
-	require.Contains(t, received, receiptVerif.BlockHash)
+	require.Contains(t, received, eth.BlockID{Hash: receiptVerif.BlockHash, Number: receiptVerif.BlockNumber.Uint64()}.String())
 
 	// Verify that everything that was received was published
 	require.GreaterOrEqual(t, len(published), len(received))

op-node/eth/label.go

@@ -17,3 +17,9 @@ const (
 	// - L2: Derived chain tip from finalized L1 data
 	Finalized = "finalized"
 )
+
+func (label BlockLabel) Arg() any { return string(label) }
+
+func (BlockLabel) CheckID(id BlockID) error {
+	return nil
+}

op-node/flags/flags.go

@@ -175,6 +175,13 @@ var (
 		EnvVar:   prefixEnvVar("L2_BACKUP_UNSAFE_SYNC_RPC"),
 		Required: false,
 	}
+	BackupL2UnsafeSyncRPCTrustRPC = cli.StringFlag{
+		Name: "l2.backup-unsafe-sync-rpc.trustrpc",
+		Usage: "Like l1.trustrpc, configure if response data from the RPC needs to be verified, e.g. blockhash computation." +
+			"This does not include checks if the blockhash is part of the canonical chain.",
+		EnvVar:   prefixEnvVar("L2_BACKUP_UNSAFE_SYNC_RPC_TRUST_RPC"),
+		Required: false,
+	}
 )
 
 var requiredFlags = []cli.Flag{
@@ -207,6 +214,7 @@ var optionalFlags = []cli.Flag{
 	HeartbeatMonikerFlag,
 	HeartbeatURLFlag,
 	BackupL2UnsafeSyncRPC,
+	BackupL2UnsafeSyncRPCTrustRPC,
 }
 
 // Flags contains the list of configuration options available to the binary.

op-node/flags/p2p_flags.go

@@ -34,6 +34,15 @@ var (
 		Value:    "none",
 		EnvVar:   p2pEnv("PEER_SCORING"),
 	}
+	PeerScoreBands = cli.StringFlag{
+		Name: "p2p.score.bands",
+		Usage: "Sets the peer score bands used primarily for peer score metrics. " +
+			"Should be provided in following format: <threshold>:<label>;<threshold>:<label>;..." +
+			"For example: -40:graylist;-20:restricted;0:nopx;20:friend;",
+		Required: false,
+		Value:    "-40:graylist;-20:restricted;0:nopx;20:friend;",
+		EnvVar:   p2pEnv("SCORE_BANDS"),
+	}
 
 	// Banning Flag - whether or not we want to act on the scoring
 	Banning = cli.BoolFlag{
@@ -276,6 +285,10 @@ var p2pFlags = []cli.Flag{
 	NoDiscovery,
 	P2PPrivPath,
 	P2PPrivRaw,
+	PeerScoring,
+	PeerScoreBands,
+	Banning,
+	TopicScoring,
 	ListenIP,
 	ListenTCPPort,
 	ListenUDPPort,

op-node/metrics/metrics.go

@@ -15,7 +15,6 @@ import (
 
 	pb "github.com/libp2p/go-libp2p-pubsub/pb"
 	libp2pmetrics "github.com/libp2p/go-libp2p/core/metrics"
-	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/collectors"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -66,7 +65,7 @@ type Metricer interface {
 	RecordSequencerSealingTime(duration time.Duration)
 	Document() []metrics.DocumentedMetric
 	// P2P Metrics
-	RecordPeerScoring(peerID peer.ID, score float64)
+	SetPeerScores(scores map[string]float64)
 }
 
 // Metrics tracks all the metrics for the op-node.
@@ -287,21 +286,24 @@ func NewMetrics(procName string) *Metrics {
 			Name:      "peer_count",
 			Help:      "Count of currently connected p2p peers",
 		}),
-		StreamCount: factory.NewGauge(prometheus.GaugeOpts{
-			Namespace: ns,
-			Subsystem: "p2p",
-			Name:      "stream_count",
-			Help:      "Count of currently connected p2p streams",
-		}),
+		// Notice: We cannot use peer ids as [Labels] in the GaugeVec
+		// since peer ids would open a service attack vector.
+		// Each peer id would be a separate metric, flooding prometheus.
+		//
+		// [Labels]: https://prometheus.io/docs/practices/naming/#labels
 		PeerScores: factory.NewGaugeVec(prometheus.GaugeOpts{
 			Namespace: ns,
 			Subsystem: "p2p",
 			Name:      "peer_scores",
-			Help:      "Peer scoring",
+			Help:      "Count of peer scores grouped by score",
 		}, []string{
-			// No label names here since peer ids would open a service attack vector.
-			// Each peer id would be a separate metric, flooding prometheus.
-			// See: https://prometheus.io/docs/practices/naming/#labels
+			"band",
+		}),
+		StreamCount: factory.NewGauge(prometheus.GaugeOpts{
+			Namespace: ns,
+			Subsystem: "p2p",
+			Name:      "stream_count",
+			Help:      "Count of currently connected p2p streams",
 		}),
 		GossipEventsTotal: factory.NewCounterVec(prometheus.CounterOpts{
 			Namespace: ns,
@@ -350,6 +352,14 @@ func NewMetrics(procName string) *Metrics {
 	}
 }
 
+// SetPeerScores updates the peer score [prometheus.GaugeVec].
+// This takes a map of labels to scores.
+func (m *Metrics) SetPeerScores(scores map[string]float64) {
+	for label, score := range scores {
+		m.PeerScores.WithLabelValues(label).Set(score)
+	}
+}
+
 // RecordInfo sets a pseudo-metric that contains versioning and
 // config info for the opnode.
 func (m *Metrics) RecordInfo(version string) {
@@ -491,10 +501,6 @@ func (m *Metrics) RecordGossipEvent(evType int32) {
 	m.GossipEventsTotal.WithLabelValues(pb.TraceEvent_Type_name[evType]).Inc()
 }
 
-func (m *Metrics) RecordPeerScoring(peerID peer.ID, score float64) {
-	m.PeerScores.WithLabelValues(peerID.String()).Set(score)
-}
-
 func (m *Metrics) IncPeerCount() {
 	m.PeerCount.Inc()
 }
@@ -627,7 +633,7 @@ func (n *noopMetricer) RecordSequencerReset() {
 func (n *noopMetricer) RecordGossipEvent(evType int32) {
 }
 
-func (n *noopMetricer) RecordPeerScoring(peerID peer.ID, score float64) {
+func (n *noopMetricer) SetPeerScores(scores map[string]float64) {
 }
 
 func (n *noopMetricer) IncPeerCount() {

op-node/node/client.go

@@ -20,7 +20,9 @@ type L2EndpointSetup interface {
 }
 
 type L2SyncEndpointSetup interface {
-	Setup(ctx context.Context, log log.Logger) (cl client.RPC, err error)
+	// Setup a RPC client to another L2 node to sync L2 blocks from.
+	// It may return a nil client with nil error if RPC based sync is not enabled.
+	Setup(ctx context.Context, log log.Logger) (cl client.RPC, trust bool, err error)
 	Check() error
 }
 
@@ -82,45 +84,45 @@ func (p *PreparedL2Endpoints) Setup(ctx context.Context, log log.Logger) (client
 
 // L2SyncEndpointConfig contains configuration for the fallback sync endpoint
 type L2SyncEndpointConfig struct {
-	// Address of the L2 RPC to use for backup sync
+	// Address of the L2 RPC to use for backup sync, may be empty if RPC alt-sync is disabled.
 	L2NodeAddr string
+	TrustRPC   bool
 }
 
 var _ L2SyncEndpointSetup = (*L2SyncEndpointConfig)(nil)
 
-func (cfg *L2SyncEndpointConfig) Setup(ctx context.Context, log log.Logger) (client.RPC, error) {
+// Setup creates an RPC client to sync from.
+// It will return nil without error if no sync method is configured.
+func (cfg *L2SyncEndpointConfig) Setup(ctx context.Context, log log.Logger) (cl client.RPC, trust bool, err error) {
+	if cfg.L2NodeAddr == "" {
+		return nil, false, nil
+	}
 	l2Node, err := client.NewRPC(ctx, log, cfg.L2NodeAddr)
 	if err != nil {
-		return nil, err
+		return nil, false, err
 	}
 
-	return l2Node, nil
+	return l2Node, cfg.TrustRPC, nil
 }
 
 func (cfg *L2SyncEndpointConfig) Check() error {
-	if cfg.L2NodeAddr == "" {
-		return errors.New("empty L2 Node Address")
-	}
-
+	// empty addr is valid, as it is optional.
 	return nil
 }
 
-type L2SyncRPCConfig struct {
-	// RPC endpoint to use for syncing
-	Rpc client.RPC
+type PreparedL2SyncEndpoint struct {
+	// RPC endpoint to use for syncing, may be nil if RPC alt-sync is disabled.
+	Client   client.RPC
+	TrustRPC bool
 }
 
-var _ L2SyncEndpointSetup = (*L2SyncRPCConfig)(nil)
+var _ L2SyncEndpointSetup = (*PreparedL2SyncEndpoint)(nil)
 
-func (cfg *L2SyncRPCConfig) Setup(ctx context.Context, log log.Logger) (client.RPC, error) {
-	return cfg.Rpc, nil
+func (cfg *PreparedL2SyncEndpoint) Setup(ctx context.Context, log log.Logger) (cl client.RPC, trust bool, err error) {
+	return cfg.Client, cfg.TrustRPC, nil
 }
 
-func (cfg *L2SyncRPCConfig) Check() error {
-	if cfg.Rpc == nil {
-		return errors.New("rpc cannot be nil")
-	}
-
+func (cfg *PreparedL2SyncEndpoint) Check() error {
 	return nil
 }
 

op-node/node/config.go

@@ -80,6 +80,9 @@ func (cfg *Config) Check() error {
 	if err := cfg.L2.Check(); err != nil {
 		return fmt.Errorf("l2 endpoint config error: %w", err)
 	}
+	if err := cfg.L2Sync.Check(); err != nil {
+		return fmt.Errorf("sync config error: %w", err)
+	}
 	if err := cfg.Rollup.Check(); err != nil {
 		return fmt.Errorf("rollup config error: %w", err)
 	}

op-node/node/node.go

@@ -33,6 +33,7 @@ type OpNode struct {
 	l1Source  *sources.L1Client     // L1 Client to fetch data from
 	l2Driver  *driver.Driver        // L2 Engine to Sync
 	l2Source  *sources.EngineClient // L2 Execution Engine RPC bindings
+	rpcSync   *sources.SyncClient   // Alt-sync RPC client, optional (may be nil)
 	server    *rpcServer            // RPC server hosting the rollup-node API
 	p2pNode   *p2p.NodeP2P          // P2P node functionality
 	p2pSigner p2p.Signer            // p2p gogssip application messages will be signed with this signer
@@ -86,6 +87,9 @@ func (n *OpNode) init(ctx context.Context, cfg *Config, snapshotLog log.Logger)
 	if err := n.initL2(ctx, cfg, snapshotLog); err != nil {
 		return err
 	}
+	if err := n.initRPCSync(ctx, cfg); err != nil {
+		return err
+	}
 	if err := n.initP2PSigner(ctx, cfg); err != nil {
 		return err
 	}
@@ -197,29 +201,27 @@ func (n *OpNode) initL2(ctx context.Context, cfg *Config, snapshotLog log.Logger
 		return err
 	}
 
-	var syncClient *sources.SyncClient
-	// If the L2 sync config is present, use it to create a sync client
-	if cfg.L2Sync != nil {
-		if err := cfg.L2Sync.Check(); err != nil {
-			log.Info("L2 sync config is not present, skipping L2 sync client setup", "err", err)
-		} else {
-			rpcSyncClient, err := cfg.L2Sync.Setup(ctx, n.log)
-			if err != nil {
-				return fmt.Errorf("failed to setup L2 execution-engine RPC client for backup sync: %w", err)
-			}
+	n.l2Driver = driver.NewDriver(&cfg.Driver, &cfg.Rollup, n.l2Source, n.l1Source, n, n, n.log, snapshotLog, n.metrics)
 
-			// The sync client's RPC is always trusted
-			config := sources.SyncClientDefaultConfig(&cfg.Rollup, true)
+	return nil
+}
 
-			syncClient, err = sources.NewSyncClient(n.OnUnsafeL2Payload, rpcSyncClient, n.log, n.metrics.L2SourceCache, config)
-			if err != nil {
-				return fmt.Errorf("failed to create sync client: %w", err)
-			}
-		}
+func (n *OpNode) initRPCSync(ctx context.Context, cfg *Config) error {
+	rpcSyncClient, trustRPC, err := cfg.L2Sync.Setup(ctx, n.log)
+	if err != nil {
+		return fmt.Errorf("failed to setup L2 execution-engine RPC client for backup sync: %w", err)
+	}
+	if rpcSyncClient == nil { // if no RPC client is configured to sync from, then don't add the RPC sync client
+		return nil
 	}
 
-	n.l2Driver = driver.NewDriver(&cfg.Driver, &cfg.Rollup, n.l2Source, n.l1Source, syncClient, n, n.log, snapshotLog, n.metrics)
+	config := sources.SyncClientDefaultConfig(&cfg.Rollup, trustRPC)
 
+	syncClient, err := sources.NewSyncClient(n.OnUnsafeL2Payload, rpcSyncClient, n.log, n.metrics.L2SourceCache, config)
+	if err != nil {
+		return fmt.Errorf("failed to create sync client: %w", err)
+	}
+	n.rpcSync = syncClient
 	return nil
 }
 
@@ -292,11 +294,12 @@ func (n *OpNode) Start(ctx context.Context) error {
 	}
 
 	// If the backup unsafe sync client is enabled, start its event loop
-	if n.l2Driver.L2SyncCl != nil {
-		if err := n.l2Driver.L2SyncCl.Start(); err != nil {
+	if n.rpcSync != nil {
+		if err := n.rpcSync.Start(); err != nil {
 			n.log.Error("Could not start the backup sync client", "err", err)
 			return err
 		}
+		n.log.Info("Started L2-RPC sync service")
 	}
 
 	return nil
@@ -375,6 +378,14 @@ func (n *OpNode) OnUnsafeL2Payload(ctx context.Context, from peer.ID, payload *e
 	return nil
 }
 
+func (n *OpNode) RequestL2Range(ctx context.Context, start, end uint64) error {
+	if n.rpcSync != nil {
+		return n.rpcSync.RequestL2Range(ctx, start, end)
+	}
+	n.log.Debug("ignoring request to sync L2 range, no sync method available")
+	return nil
+}
+
 func (n *OpNode) P2P() p2p.Node {
 	return n.p2pNode
 }
@@ -413,8 +424,8 @@ func (n *OpNode) Close() error {
 		}
 
 		// If the L2 sync client is present & running, close it.
-		if n.l2Driver.L2SyncCl != nil {
-			if err := n.l2Driver.L2SyncCl.Close(); err != nil {
+		if n.rpcSync != nil {
+			if err := n.rpcSync.Close(); err != nil {
 				result = multierror.Append(result, fmt.Errorf("failed to close L2 engine backup sync client cleanly: %w", err))
 			}
 		}

op-node/p2p/band_scorer_test.go

+package p2p
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestBandScorer_ParseDefault tests the [BandScorer.Parse] function
+// on the default band scores cli flag value.
+func TestBandScorer_ParseDefault(t *testing.T) {
+	// Create a new band scorer.
+	bandScorer, err := NewBandScorer("-40:graylist;-20:restricted;0:nopx;20:friend;")
+	require.NoError(t, err)
+
+	// Validate the [BandScorer] internals.
+	require.ElementsMatch(t, bandScorer.bands, []scorePair{
+		{band: "graylist", threshold: -40},
+		{band: "restricted", threshold: -20},
+		{band: "nopx", threshold: 0},
+		{band: "friend", threshold: 20},
+	})
+}
+
+// TestBandScorer_BucketCorrectly tests the [BandScorer.Bucket] function
+// on a variety of scores.
+func TestBandScorer_BucketCorrectly(t *testing.T) {
+	// Create a new band scorer.
+	bandScorer, err := NewBandScorer("-40:graylist;-20:restricted;0:nopx;20:friend;")
+	require.NoError(t, err)
+
+	// Validate the [BandScorer] internals.
+	require.Equal(t, bandScorer.Bucket(-100), "graylist")
+	require.Equal(t, bandScorer.Bucket(-40), "graylist")
+	require.Equal(t, bandScorer.Bucket(-39), "restricted")
+	require.Equal(t, bandScorer.Bucket(-20), "restricted")
+	require.Equal(t, bandScorer.Bucket(-19), "nopx")
+	require.Equal(t, bandScorer.Bucket(0), "nopx")
+	require.Equal(t, bandScorer.Bucket(1), "friend")
+	require.Equal(t, bandScorer.Bucket(20), "friend")
+	require.Equal(t, bandScorer.Bucket(21), "friend")
+}
+
+// TestBandScorer_BucketInverted tests the [BandScorer.Bucket] function
+// on a variety of scores, in descending order.
+func TestBandScorer_BucketInverted(t *testing.T) {
+	// Create a new band scorer.
+	bandScorer, err := NewBandScorer("20:friend;0:nopx;-20:restricted;-40:graylist;")
+	require.NoError(t, err)
+
+	// Validate the [BandScorer] internals.
+	require.Equal(t, bandScorer.Bucket(-100), "graylist")
+	require.Equal(t, bandScorer.Bucket(-40), "graylist")
+	require.Equal(t, bandScorer.Bucket(-39), "restricted")
+	require.Equal(t, bandScorer.Bucket(-20), "restricted")
+	require.Equal(t, bandScorer.Bucket(-19), "nopx")
+	require.Equal(t, bandScorer.Bucket(0), "nopx")
+	require.Equal(t, bandScorer.Bucket(1), "friend")
+	require.Equal(t, bandScorer.Bucket(20), "friend")
+	require.Equal(t, bandScorer.Bucket(21), "friend")
+}
+
+// TestBandScorer_ParseEmpty tests the [BandScorer.Parse] function
+// on an empty string.
+func TestBandScorer_ParseEmpty(t *testing.T) {
+	// Create a band scorer on an empty string.
+	bandScorer, err := NewBandScorer("")
+	require.NoError(t, err)
+
+	// Validate the [BandScorer] internals.
+	require.Len(t, bandScorer.bands, 0)
+}
+
+// TestBandScorer_ParseWhitespace tests the [BandScorer.Parse] function
+// on a variety of whitespaced strings.
+func TestBandScorer_ParseWhitespace(t *testing.T) {
+	// Create a band scorer on an empty string.
+	bandScorer, err := NewBandScorer("  ;  ;  ;  ")
+	require.NoError(t, err)
+
+	// Validate the [BandScorer] internals.
+	require.Len(t, bandScorer.bands, 0)
+}

op-node/p2p/cli/load_config.go

@@ -58,6 +58,10 @@ func NewConfig(ctx *cli.Context, blockTime uint64) (*p2p.Config, error) {
 		return nil, fmt.Errorf("failed to load p2p peer scoring options: %w", err)
 	}
 
+	if err := loadPeerScoreBands(conf, ctx); err != nil {
+		return nil, fmt.Errorf("failed to load p2p peer score bands: %w", err)
+	}
+
 	if err := loadBanningOption(conf, ctx); err != nil {
 		return nil, fmt.Errorf("failed to load banning option: %w", err)
 	}
@@ -121,6 +125,17 @@ func loadPeerScoringParams(conf *p2p.Config, ctx *cli.Context, blockTime uint64)
 	return nil
 }
 
+// loadPeerScoreBands loads [p2p.BandScorer] from the CLI context.
+func loadPeerScoreBands(conf *p2p.Config, ctx *cli.Context) error {
+	scoreBands := ctx.GlobalString(flags.PeerScoreBands.Name)
+	bandScorer, err := p2p.NewBandScorer(scoreBands)
+	if err != nil {
+		return err
+	}
+	conf.BandScoreThresholds = *bandScorer
+	return nil
+}
+
 // loadBanningOption loads whether or not to ban peers from the CLI context.
 func loadBanningOption(conf *p2p.Config, ctx *cli.Context) error {
 	ban := ctx.GlobalBool(flags.Banning.Name)

op-node/p2p/config.go

@@ -54,6 +54,9 @@ type Config struct {
 	PeerScoring  pubsub.PeerScoreParams
 	TopicScoring pubsub.TopicScoreParams
 
+	// Peer Score Band Thresholds
+	BandScoreThresholds BandScoreThresholds
+
 	// Whether to ban peers based on their [PeerScoring] score.
 	BanningEnabled bool
 
@@ -151,6 +154,10 @@ func (conf *Config) PeerScoringParams() *pubsub.PeerScoreParams {
 	return &conf.PeerScoring
 }
 
+func (conf *Config) PeerBandScorer() *BandScoreThresholds {
+	return &conf.BandScoreThresholds
+}
+
 func (conf *Config) BanPeers() bool {
 	return conf.BanningEnabled
 }

op-node/p2p/gossip.go

@@ -55,6 +55,7 @@ type GossipSetupConfigurables interface {
 	TopicScoringParams() *pubsub.TopicScoreParams
 	BanPeers() bool
 	ConfigureGossip(params *pubsub.GossipSubParams) []pubsub.Option
+	PeerBandScorer() *BandScoreThresholds
 }
 
 type GossipRuntimeConfig interface {
@@ -64,7 +65,8 @@ type GossipRuntimeConfig interface {
 //go:generate mockery --name GossipMetricer
 type GossipMetricer interface {
 	RecordGossipEvent(evType int32)
-	RecordPeerScoring(peerID peer.ID, score float64)
+	// Peer Scoring Metric Funcs
+	SetPeerScores(map[string]float64)
 }
 
 func blocksTopicV1(cfg *rollup.Config) string {

op-node/p2p/mocks/ConnectionGater.go

-// Code generated by mockery v2.14.0. DO NOT EDIT.
+// Code generated by mockery v2.22.1. DO NOT EDIT.
 
 package mocks
 
@@ -123,13 +123,16 @@ func (_m *ConnectionGater) InterceptUpgraded(_a0 network.Conn) (bool, control.Di
 	ret := _m.Called(_a0)
 
 	var r0 bool
+	var r1 control.DisconnectReason
+	if rf, ok := ret.Get(0).(func(network.Conn) (bool, control.DisconnectReason)); ok {
+		return rf(_a0)
+	}
 	if rf, ok := ret.Get(0).(func(network.Conn) bool); ok {
 		r0 = rf(_a0)
 	} else {
 		r0 = ret.Get(0).(bool)
 	}
 
-	var r1 control.DisconnectReason
 	if rf, ok := ret.Get(1).(func(network.Conn) control.DisconnectReason); ok {
 		r1 = rf(_a0)
 	} else {

op-node/p2p/mocks/GossipMetricer.go

-// Code generated by mockery v2.14.0. DO NOT EDIT.
+// Code generated by mockery v2.22.1. DO NOT EDIT.
 
 package mocks
 
-import (
-	mock "github.com/stretchr/testify/mock"
-
-	peer "github.com/libp2p/go-libp2p/core/peer"
-)
+import mock "github.com/stretchr/testify/mock"
 
 // GossipMetricer is an autogenerated mock type for the GossipMetricer type
 type GossipMetricer struct {
@@ -18,9 +14,9 @@ func (_m *GossipMetricer) RecordGossipEvent(evType int32) {
 	_m.Called(evType)
 }
 
-// RecordPeerScoring provides a mock function with given fields: peerID, score
-func (_m *GossipMetricer) RecordPeerScoring(peerID peer.ID, score float64) {
-	_m.Called(peerID, score)
+// SetPeerScores provides a mock function with given fields: _a0
+func (_m *GossipMetricer) SetPeerScores(_a0 map[string]float64) {
+	_m.Called(_a0)
 }
 
 type mockConstructorTestingTNewGossipMetricer interface {

op-node/p2p/mocks/PeerGater.go

-// Code generated by mockery v2.14.0. DO NOT EDIT.
+// Code generated by mockery v2.22.1. DO NOT EDIT.
 
 package mocks
 

op-node/p2p/mocks/Peerstore.go

-// Code generated by mockery v2.14.0. DO NOT EDIT.
+// Code generated by mockery v2.22.1. DO NOT EDIT.
 
 package mocks
 

op-node/p2p/peer_gater.go

@@ -43,11 +43,15 @@ func (s *gater) Update(id peer.ID, score float64) {
 	if score < PeerScoreThreshold && s.banEnabled {
 		s.log.Warn("peer blocking enabled, blocking peer", "id", id.String(), "score", score)
 		err := s.connGater.BlockPeer(id)
-		s.log.Warn("connection gater failed to block peer", id.String(), "err", err)
+		if err != nil {
+			s.log.Warn("connection gater failed to block peer", "id", id.String(), "err", err)
+		}
 	}
 	// Unblock peers whose score has recovered to an acceptable level
 	if (score > PeerScoreThreshold) && slices.Contains(s.connGater.ListBlockedPeers(), id) {
 		err := s.connGater.UnblockPeer(id)
-		s.log.Warn("connection gater failed to unblock peer", id.String(), "err", err)
+		if err != nil {
+			s.log.Warn("connection gater failed to unblock peer", "id", id.String(), "err", err)
+		}
 	}
 }

op-node/p2p/peer_scorer.go

 package p2p
 
 import (
+	"fmt"
+	"sort"
+	"strconv"
+	"strings"
+
 	log "github.com/ethereum/go-ethereum/log"
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	peer "github.com/libp2p/go-libp2p/core/peer"
 )
 
 type scorer struct {
-	peerStore Peerstore
-	metricer  GossipMetricer
-	log       log.Logger
-	gater     PeerGater
+	peerStore           Peerstore
+	metricer            GossipMetricer
+	log                 log.Logger
+	gater               PeerGater
+	bandScoreThresholds *BandScoreThresholds
+}
+
+// scorePair holds a band and its corresponding threshold.
+type scorePair struct {
+	band      string
+	threshold float64
+}
+
+// BandScoreThresholds holds the thresholds for classifying peers
+// into different score bands.
+type BandScoreThresholds struct {
+	bands []scorePair
+}
+
+// NewBandScorer constructs a new [BandScoreThresholds] instance.
+func NewBandScorer(str string) (*BandScoreThresholds, error) {
+	s := &BandScoreThresholds{
+		bands: make([]scorePair, 0),
+	}
+
+	for _, band := range strings.Split(str, ";") {
+		// Skip empty band strings.
+		band := strings.TrimSpace(band)
+		if band == "" {
+			continue
+		}
+		split := strings.Split(band, ":")
+		if len(split) != 2 {
+			return nil, fmt.Errorf("invalid score band: %s", band)
+		}
+		threshold, err := strconv.ParseFloat(split[0], 64)
+		if err != nil {
+			return nil, err
+		}
+		s.bands = append(s.bands, scorePair{
+			band:      split[1],
+			threshold: threshold,
+		})
+	}
+
+	// Order the bands by threshold in ascending order.
+	sort.Slice(s.bands, func(i, j int) bool {
+		return s.bands[i].threshold < s.bands[j].threshold
+	})
+
+	return s, nil
+}
+
+// Bucket returns the appropriate band for a given score.
+func (s *BandScoreThresholds) Bucket(score float64) string {
+	for _, pair := range s.bands {
+		if score <= pair.threshold {
+			return pair.band
+		}
+	}
+	// If there is no band threshold higher than the score,
+	// the peer must be placed in the highest bucket.
+	if len(s.bands) > 0 {
+		return s.bands[len(s.bands)-1].band
+	}
+	return ""
 }
 
 // Peerstore is a subset of the libp2p peerstore.Peerstore interface.
@@ -34,12 +101,13 @@ type Scorer interface {
 }
 
 // NewScorer returns a new peer scorer.
-func NewScorer(peerGater PeerGater, peerStore Peerstore, metricer GossipMetricer, log log.Logger) Scorer {
+func NewScorer(peerGater PeerGater, peerStore Peerstore, metricer GossipMetricer, bandScoreThresholds *BandScoreThresholds, log log.Logger) Scorer {
 	return &scorer{
-		peerStore: peerStore,
-		metricer:  metricer,
-		log:       log,
-		gater:     peerGater,
+		peerStore:           peerStore,
+		metricer:            metricer,
+		log:                 log,
+		gater:               peerGater,
+		bandScoreThresholds: bandScoreThresholds,
 	}
 }
 
@@ -48,13 +116,13 @@ func NewScorer(peerGater PeerGater, peerStore Peerstore, metricer GossipMetricer
 // The returned [pubsub.ExtendedPeerScoreInspectFn] is called with a mapping of peer IDs to peer score snapshots.
 func (s *scorer) SnapshotHook() pubsub.ExtendedPeerScoreInspectFn {
 	return func(m map[peer.ID]*pubsub.PeerScoreSnapshot) {
+		scoreMap := make(map[string]float64)
 		for id, snap := range m {
-			// Record peer score in the metricer
-			s.metricer.RecordPeerScoring(id, snap.Score)
-
-			// Update with the peer gater
+			band := s.bandScoreThresholds.Bucket(snap.Score)
+			scoreMap[band] += 1
 			s.gater.Update(id, snap.Score)
 		}
+		s.metricer.SetPeerScores(scoreMap)
 	}
 }
 

op-node/p2p/peer_scorer_test.go

@@ -20,15 +20,18 @@ type PeerScorerTestSuite struct {
 	mockGater    *p2pMocks.PeerGater
 	mockStore    *p2pMocks.Peerstore
 	mockMetricer *p2pMocks.GossipMetricer
+	bandScorer   *p2p.BandScoreThresholds
 	logger       log.Logger
 }
 
 // SetupTest sets up the test suite.
 func (testSuite *PeerScorerTestSuite) SetupTest() {
 	testSuite.mockGater = &p2pMocks.PeerGater{}
-	// testSuite.mockConnGater = &p2pMocks.ConnectionGater{}
 	testSuite.mockStore = &p2pMocks.Peerstore{}
 	testSuite.mockMetricer = &p2pMocks.GossipMetricer{}
+	bandScorer, err := p2p.NewBandScorer("0:graylist;")
+	testSuite.NoError(err)
+	testSuite.bandScorer = bandScorer
 	testSuite.logger = testlog.Logger(testSuite.T(), log.LvlError)
 }
 
@@ -37,45 +40,49 @@ func TestPeerScorer(t *testing.T) {
 	suite.Run(t, new(PeerScorerTestSuite))
 }
 
-// TestPeerScorerOnConnect ensures we can call the OnConnect method on the peer scorer.
-func (testSuite *PeerScorerTestSuite) TestPeerScorerOnConnect() {
+// TestScorer_OnConnect ensures we can call the OnConnect method on the peer scorer.
+func (testSuite *PeerScorerTestSuite) TestScorer_OnConnect() {
 	scorer := p2p.NewScorer(
 		testSuite.mockGater,
 		testSuite.mockStore,
 		testSuite.mockMetricer,
+		testSuite.bandScorer,
 		testSuite.logger,
 	)
 	scorer.OnConnect()
 }
 
-// TestPeerScorerOnDisconnect ensures we can call the OnDisconnect method on the peer scorer.
-func (testSuite *PeerScorerTestSuite) TestPeerScorerOnDisconnect() {
+// TestScorer_OnDisconnect ensures we can call the OnDisconnect method on the peer scorer.
+func (testSuite *PeerScorerTestSuite) TestScorer_OnDisconnect() {
 	scorer := p2p.NewScorer(
 		testSuite.mockGater,
 		testSuite.mockStore,
 		testSuite.mockMetricer,
+		testSuite.bandScorer,
 		testSuite.logger,
 	)
 	scorer.OnDisconnect()
 }
 
-// TestSnapshotHook tests running the snapshot hook on the peer scorer.
-func (testSuite *PeerScorerTestSuite) TestSnapshotHook() {
+// TestScorer_SnapshotHook tests running the snapshot hook on the peer scorer.
+func (testSuite *PeerScorerTestSuite) TestScorer_SnapshotHook() {
 	scorer := p2p.NewScorer(
 		testSuite.mockGater,
 		testSuite.mockStore,
 		testSuite.mockMetricer,
+		testSuite.bandScorer,
 		testSuite.logger,
 	)
 	inspectFn := scorer.SnapshotHook()
 
-	// Mock the snapshot updates
-	// This doesn't return anything
-	testSuite.mockMetricer.On("RecordPeerScoring", peer.ID("peer1"), float64(-100)).Return(nil)
-
 	// Mock the peer gater call
 	testSuite.mockGater.On("Update", peer.ID("peer1"), float64(-100)).Return(nil)
 
+	// The metricer should then be called with the peer score band map
+	testSuite.mockMetricer.On("SetPeerScores", map[string]float64{
+		"graylist": 1,
+	}).Return(nil)
+
 	// Apply the snapshot
 	snapshotMap := map[peer.ID]*pubsub.PeerScoreSnapshot{
 		peer.ID("peer1"): {
@@ -85,24 +92,26 @@ func (testSuite *PeerScorerTestSuite) TestSnapshotHook() {
 	inspectFn(snapshotMap)
 }
 
-// TestSnapshotHookBlockPeer tests running the snapshot hook on the peer scorer with a peer score below the threshold.
+// TestScorer_SnapshotHookBlocksPeer tests running the snapshot hook on the peer scorer with a peer score below the threshold.
 // This implies that the peer should be blocked.
-func (testSuite *PeerScorerTestSuite) TestSnapshotHookBlockPeer() {
+func (testSuite *PeerScorerTestSuite) TestScorer_SnapshotHookBlocksPeer() {
 	scorer := p2p.NewScorer(
 		testSuite.mockGater,
 		testSuite.mockStore,
 		testSuite.mockMetricer,
+		testSuite.bandScorer,
 		testSuite.logger,
 	)
 	inspectFn := scorer.SnapshotHook()
 
-	// Mock the snapshot updates
-	// This doesn't return anything
-	testSuite.mockMetricer.On("RecordPeerScoring", peer.ID("peer1"), float64(-101)).Return(nil)
-
 	// Mock the peer gater call
 	testSuite.mockGater.On("Update", peer.ID("peer1"), float64(-101)).Return(nil)
 
+	// The metricer should then be called with the peer score band map
+	testSuite.mockMetricer.On("SetPeerScores", map[string]float64{
+		"graylist": 1,
+	}).Return(nil)
+
 	// Apply the snapshot
 	snapshotMap := map[peer.ID]*pubsub.PeerScoreSnapshot{
 		peer.ID("peer1"): {

op-node/p2p/peer_scores.go

@@ -14,7 +14,7 @@ func ConfigurePeerScoring(h host.Host, g ConnectionGater, gossipConf GossipSetup
 	peerScoreThresholds := NewPeerScoreThresholds()
 	banEnabled := gossipConf.BanPeers()
 	peerGater := NewPeerGater(g, log, banEnabled)
-	scorer := NewScorer(peerGater, h.Peerstore(), m, log)
+	scorer := NewScorer(peerGater, h.Peerstore(), m, gossipConf.PeerBandScorer(), log)
 	opts := []pubsub.Option{}
 	// Check the app specific score since libp2p doesn't export it's [validate] function :/
 	if peerScoreParams != nil && peerScoreParams.AppSpecificScore != nil {

op-node/p2p/peer_scores_test.go

@@ -11,7 +11,7 @@ import (
 	p2pMocks "github.com/ethereum-optimism/optimism/op-node/p2p/mocks"
 	testlog "github.com/ethereum-optimism/optimism/op-node/testlog"
 
-	mock "github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/mock"
 	suite "github.com/stretchr/testify/suite"
 
 	log "github.com/ethereum/go-ethereum/log"
@@ -30,6 +30,7 @@ type PeerScoresTestSuite struct {
 	mockGater    *p2pMocks.ConnectionGater
 	mockStore    *p2pMocks.Peerstore
 	mockMetricer *p2pMocks.GossipMetricer
+	bandScorer   p2p.BandScoreThresholds
 	logger       log.Logger
 }
 
@@ -38,6 +39,9 @@ func (testSuite *PeerScoresTestSuite) SetupTest() {
 	testSuite.mockGater = &p2pMocks.ConnectionGater{}
 	testSuite.mockStore = &p2pMocks.Peerstore{}
 	testSuite.mockMetricer = &p2pMocks.GossipMetricer{}
+	bandScorer, err := p2p.NewBandScorer("0:graylist;")
+	testSuite.NoError(err)
+	testSuite.bandScorer = *bandScorer
 	testSuite.logger = testlog.Logger(testSuite.T(), log.LvlError)
 }
 
@@ -68,6 +72,7 @@ func newGossipSubs(testSuite *PeerScoresTestSuite, ctx context.Context, hosts []
 		rt := pubsub.DefaultGossipSubRouter(h)
 		opts := []pubsub.Option{}
 		opts = append(opts, p2p.ConfigurePeerScoring(h, testSuite.mockGater, &p2p.Config{
+			BandScoreThresholds: testSuite.bandScorer,
 			PeerScoring: pubsub.PeerScoreParams{
 				AppSpecificScore: func(p peer.ID) float64 {
 					if p == hosts[0].ID() {
@@ -118,8 +123,7 @@ func (testSuite *PeerScoresTestSuite) TestNegativeScores() {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	testSuite.mockMetricer.On("RecordPeerScoring", mock.Anything, float64(0)).Return(nil)
-	testSuite.mockMetricer.On("RecordPeerScoring", mock.Anything, float64(-1000)).Return(nil)
+	testSuite.mockMetricer.On("SetPeerScores", mock.Anything).Return(nil)
 
 	testSuite.mockGater.On("ListBlockedPeers").Return([]peer.ID{})
 

op-node/p2p/prepared.go

@@ -68,6 +68,10 @@ func (p *Prepared) PeerScoringParams() *pubsub.PeerScoreParams {
 	return nil
 }
 
+func (p *Prepared) PeerBandScorer() *BandScoreThresholds {
+	return nil
+}
+
 func (p *Prepared) BanPeers() bool {
 	return false
 }

op-node/rollup/derive/engine_queue.go

@@ -107,7 +107,7 @@ type EngineQueue struct {
 	// The queued-up attributes
 	safeAttributesParent eth.L2BlockRef
 	safeAttributes       *eth.PayloadAttributes
-	unsafePayloads       PayloadsQueue // queue of unsafe payloads, ordered by ascending block number, may have gaps
+	unsafePayloads       *PayloadsQueue // queue of unsafe payloads, ordered by ascending block number, may have gaps and duplicates
 
 	// Tracks which L2 blocks where last derived from which L1 block. At most finalityLookback large.
 	finalityData []FinalityData
@@ -127,18 +127,14 @@ var _ EngineControl = (*EngineQueue)(nil)
 // NewEngineQueue creates a new EngineQueue, which should be Reset(origin) before use.
 func NewEngineQueue(log log.Logger, cfg *rollup.Config, engine Engine, metrics Metrics, prev NextAttributesProvider, l1Fetcher L1Fetcher) *EngineQueue {
 	return &EngineQueue{
-		log:          log,
-		cfg:          cfg,
-		engine:       engine,
-		metrics:      metrics,
-		finalityData: make([]FinalityData, 0, finalityLookback),
-		unsafePayloads: PayloadsQueue{
-			MaxSize:  maxUnsafePayloadsMemory,
-			SizeFn:   payloadMemSize,
-			blockNos: make(map[uint64]bool),
-		},
-		prev:      prev,
-		l1Fetcher: l1Fetcher,
+		log:            log,
+		cfg:            cfg,
+		engine:         engine,
+		metrics:        metrics,
+		finalityData:   make([]FinalityData, 0, finalityLookback),
+		unsafePayloads: NewPayloadsQueue(maxUnsafePayloadsMemory, payloadMemSize),
+		prev:           prev,
+		l1Fetcher:      l1Fetcher,
 	}
 }
 
@@ -682,7 +678,8 @@ func (eq *EngineQueue) Reset(ctx context.Context, _ eth.L1BlockRef, _ eth.System
 	return io.EOF
 }
 
-// GetUnsafeQueueGap retrieves the current [start, end] range of the gap between the tip of the unsafe priority queue and the unsafe head.
+// GetUnsafeQueueGap retrieves the current [start, end) range (incl. start, excl. end)
+// of the gap between the tip of the unsafe priority queue and the unsafe head.
 // If there is no gap, the difference between end and start will be 0.
 func (eq *EngineQueue) GetUnsafeQueueGap(expectedNumber uint64) (start uint64, end uint64) {
 	// The start of the gap is always the unsafe head + 1
@@ -691,9 +688,11 @@ func (eq *EngineQueue) GetUnsafeQueueGap(expectedNumber uint64) (start uint64, e
 	// If the priority queue is empty, the end is the first block number at the top of the priority queue
 	// Otherwise, the end is the expected block number
 	if first := eq.unsafePayloads.Peek(); first != nil {
+		// Don't include the payload we already have in the sync range
 		end = first.ID().Number
 	} else {
-		end = expectedNumber
+		// Include the expected payload in the sync range
+		end = expectedNumber + 1
 	}
 
 	return start, end

op-node/rollup/derive/payloads_queue.go

@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 
+	"github.com/ethereum/go-ethereum/common"
+
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 )
 
@@ -48,8 +50,8 @@ func (pq *payloadsByNumber) Pop() any {
 }
 
 const (
-	// ~580 bytes per payload, with some margin for overhead
-	payloadMemFixedCost uint64 = 600
+	// ~580 bytes per payload, with some margin for overhead like map data
+	payloadMemFixedCost uint64 = 800
 	// 24 bytes per tx overhead (size of slice header in memory)
 	payloadTxMemOverhead uint64 = 24
 )
@@ -72,15 +74,25 @@ func payloadMemSize(p *eth.ExecutionPayload) uint64 {
 // without the need to use heap.Push/heap.Pop as caller.
 // PayloadsQueue maintains a MaxSize by counting and tracking sizes of added eth.ExecutionPayload entries.
 // When the size grows too large, the first (lowest block-number) payload is removed from the queue.
-// PayloadsQueue allows entries with same block number, or even full duplicates.
+// PayloadsQueue allows entries with same block number, but does not allow duplicate blocks
 type PayloadsQueue struct {
 	pq          payloadsByNumber
 	currentSize uint64
 	MaxSize     uint64
-	blockNos    map[uint64]bool
+	blockHashes map[common.Hash]struct{}
 	SizeFn      func(p *eth.ExecutionPayload) uint64
 }
 
+func NewPayloadsQueue(maxSize uint64, sizeFn func(p *eth.ExecutionPayload) uint64) *PayloadsQueue {
+	return &PayloadsQueue{
+		pq:          nil,
+		currentSize: 0,
+		MaxSize:     maxSize,
+		blockHashes: make(map[common.Hash]struct{}),
+		SizeFn:      sizeFn,
+	}
+}
+
 func (upq *PayloadsQueue) Len() int {
 	return len(upq.pq)
 }
@@ -100,8 +112,8 @@ func (upq *PayloadsQueue) Push(p *eth.ExecutionPayload) error {
 	if p == nil {
 		return errors.New("cannot add nil payload")
 	}
-	if upq.blockNos[p.ID().Number] {
-		return errors.New("cannot add duplicate payload")
+	if _, ok := upq.blockHashes[p.BlockHash]; ok {
+		return fmt.Errorf("cannot add duplicate payload %s", p.ID())
 	}
 	size := upq.SizeFn(p)
 	if size > upq.MaxSize {
@@ -115,7 +127,7 @@ func (upq *PayloadsQueue) Push(p *eth.ExecutionPayload) error {
 	for upq.currentSize > upq.MaxSize {
 		upq.Pop()
 	}
-	upq.blockNos[p.ID().Number] = true
+	upq.blockHashes[p.BlockHash] = struct{}{}
 	return nil
 }
 
@@ -137,7 +149,7 @@ func (upq *PayloadsQueue) Pop() *eth.ExecutionPayload {
 	}
 	ps := heap.Pop(&upq.pq).(payloadAndSize) // nosemgrep
 	upq.currentSize -= ps.size
-	// remove the key from the blockNos map
-	delete(upq.blockNos, ps.payload.ID().Number)
+	// remove the key from the block hashes map
+	delete(upq.blockHashes, ps.payload.BlockHash)
 	return ps.payload
 }

op-node/rollup/derive/payloads_queue_test.go

@@ -4,6 +4,7 @@ import (
 	"container/heap"
 	"testing"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/stretchr/testify/require"
 
 	"github.com/ethereum-optimism/optimism/op-node/eth"
@@ -74,20 +75,17 @@ func TestPayloadMemSize(t *testing.T) {
 }
 
 func TestPayloadsQueue(t *testing.T) {
-	pq := PayloadsQueue{
-		MaxSize:  payloadMemFixedCost * 3,
-		SizeFn:   payloadMemSize,
-		blockNos: make(map[uint64]bool),
-	}
+	pq := NewPayloadsQueue(payloadMemFixedCost*3, payloadMemSize)
 	require.Equal(t, 0, pq.Len())
 	require.Equal(t, (*eth.ExecutionPayload)(nil), pq.Peek())
 	require.Equal(t, (*eth.ExecutionPayload)(nil), pq.Pop())
 
-	a := &eth.ExecutionPayload{BlockNumber: 3}
-	b := &eth.ExecutionPayload{BlockNumber: 4}
-	c := &eth.ExecutionPayload{BlockNumber: 5}
-	d := &eth.ExecutionPayload{BlockNumber: 6}
-	bAlt := &eth.ExecutionPayload{BlockNumber: 4}
+	a := &eth.ExecutionPayload{BlockNumber: 3, BlockHash: common.Hash{3}}
+	b := &eth.ExecutionPayload{BlockNumber: 4, BlockHash: common.Hash{4}}
+	c := &eth.ExecutionPayload{BlockNumber: 5, BlockHash: common.Hash{5}}
+	d := &eth.ExecutionPayload{BlockNumber: 6, BlockHash: common.Hash{6}}
+	bAlt := &eth.ExecutionPayload{BlockNumber: 4, BlockHash: common.Hash{0xff}}
+	bDup := &eth.ExecutionPayload{BlockNumber: 4, BlockHash: common.Hash{4}}
 	require.NoError(t, pq.Push(b))
 	require.Equal(t, pq.Len(), 1)
 	require.Equal(t, pq.Peek(), b)
@@ -130,7 +128,9 @@ func TestPayloadsQueue(t *testing.T) {
 	require.Equal(t, pq.Peek(), a)
 
 	// No duplicates allowed
-	require.Error(t, pq.Push(bAlt))
+	require.Error(t, pq.Push(bDup))
+	// But reorg data allowed
+	require.NoError(t, pq.Push(bAlt))
 
 	require.NoError(t, pq.Push(d))
 	require.Equal(t, pq.Len(), 3)

op-node/rollup/driver/driver.go

@@ -10,7 +10,6 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
-	"github.com/ethereum-optimism/optimism/op-node/sources"
 )
 
 type Metrics interface {
@@ -82,8 +81,19 @@ type Network interface {
 	PublishL2Payload(ctx context.Context, payload *eth.ExecutionPayload) error
 }
 
+type AltSync interface {
+	// RequestL2Range informs the sync source that the given range of L2 blocks is missing,
+	// and should be retrieved from any available alternative syncing source.
+	// The start of the range is inclusive, the end is exclusive.
+	// The sync results should be returned back to the driver via the OnUnsafeL2Payload(ctx, payload) method.
+	// The latest requested range should always take priority over previous requests.
+	// There may be overlaps in requested ranges.
+	// An error may be returned if the scheduling fails immediately, e.g. a context timeout.
+	RequestL2Range(ctx context.Context, start, end uint64) error
+}
+
 // NewDriver composes an events handler that tracks L1 state, triggers L2 derivation, and optionally sequences new L2 blocks.
-func NewDriver(driverCfg *Config, cfg *rollup.Config, l2 L2Chain, l1 L1Chain, syncClient *sources.SyncClient, network Network, log log.Logger, snapshotLog log.Logger, metrics Metrics) *Driver {
+func NewDriver(driverCfg *Config, cfg *rollup.Config, l2 L2Chain, l1 L1Chain, altSync AltSync, network Network, log log.Logger, snapshotLog log.Logger, metrics Metrics) *Driver {
 	l1State := NewL1State(log, metrics)
 	sequencerConfDepth := NewConfDepth(driverCfg.SequencerConfDepth, l1State.L1Head, l1)
 	findL1Origin := NewL1OriginSelector(log, cfg, sequencerConfDepth)
@@ -115,6 +125,6 @@ func NewDriver(driverCfg *Config, cfg *rollup.Config, l2 L2Chain, l1 L1Chain, sy
 		l1SafeSig:        make(chan eth.L1BlockRef, 10),
 		l1FinalizedSig:   make(chan eth.L1BlockRef, 10),
 		unsafeL2Payloads: make(chan *eth.ExecutionPayload, 10),
-		L2SyncCl:         syncClient,
+		altSync:          altSync,
 	}
 }

op-node/rollup/driver/state.go

@@ -16,7 +16,6 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
-	"github.com/ethereum-optimism/optimism/op-node/sources"
 	"github.com/ethereum-optimism/optimism/op-service/backoff"
 )
 
@@ -64,8 +63,8 @@ type Driver struct {
 	l1SafeSig      chan eth.L1BlockRef
 	l1FinalizedSig chan eth.L1BlockRef
 
-	// Backup unsafe sync client
-	L2SyncCl *sources.SyncClient
+	// Interface to signal the L2 block range to sync.
+	altSync AltSync
 
 	// L2 Signals:
 
@@ -200,11 +199,12 @@ func (s *Driver) eventLoop() {
 		sequencerTimer.Reset(delay)
 	}
 
-	// Create a ticker to check if there is a gap in the engine queue every 15 seconds
-	// If there is, we send requests to the backup RPC to retrieve the missing payloads
-	// and add them to the unsafe queue.
-	altSyncTicker := time.NewTicker(15 * time.Second)
+	// Create a ticker to check if there is a gap in the engine queue. Whenever
+	// there is, we send requests to sync source to retrieve the missing payloads.
+	syncCheckInterval := time.Duration(s.config.BlockTime) * time.Second * 2
+	altSyncTicker := time.NewTicker(syncCheckInterval)
 	defer altSyncTicker.Stop()
+	lastUnsafeL2 := s.derivation.UnsafeL2Head()
 
 	for {
 		// If we are sequencing, and the L1 state is ready, update the trigger for the next sequencer action.
@@ -220,6 +220,13 @@ func (s *Driver) eventLoop() {
 			sequencerCh = nil
 		}
 
+		// If the engine is not ready, or if the L2 head is actively changing, then reset the alt-sync:
+		// there is no need to request L2 blocks when we are syncing already.
+		if head := s.derivation.UnsafeL2Head(); head != lastUnsafeL2 || !s.derivation.EngineReady() {
+			lastUnsafeL2 = head
+			altSyncTicker.Reset(syncCheckInterval)
+		}
+
 		select {
 		case <-sequencerCh:
 			payload, err := s.sequencer.RunNextSequencerAction(ctx)
@@ -237,10 +244,12 @@ func (s *Driver) eventLoop() {
 			}
 			planSequencerAction() // schedule the next sequencer action to keep the sequencing looping
 		case <-altSyncTicker.C:
-			// Check if there is a gap in the current unsafe payload queue. If there is, attempt to fetch
-			// missing payloads from the backup RPC (if it is configured).
-			if s.L2SyncCl != nil {
-				s.checkForGapInUnsafeQueue(ctx)
+			// Check if there is a gap in the current unsafe payload queue.
+			ctx, cancel := context.WithTimeout(ctx, time.Second*2)
+			err := s.checkForGapInUnsafeQueue(ctx)
+			cancel()
+			if err != nil {
+				s.log.Warn("failed to check for unsafe L2 blocks to sync", "err", err)
 			}
 		case payload := <-s.unsafeL2Payloads:
 			s.snapshot("New unsafe payload")
@@ -462,35 +471,29 @@ type hashAndErrorChannel struct {
 	err  chan error
 }
 
-// checkForGapInUnsafeQueue checks if there is a gap in the unsafe queue and attempts to retrieve the missing payloads from the backup RPC.
-// WARNING: The sync client's attempt to retrieve the missing payloads is not guaranteed to succeed, and it will fail silently (besides
-// emitting warning logs) if the requests fail.
-func (s *Driver) checkForGapInUnsafeQueue(ctx context.Context) {
+// checkForGapInUnsafeQueue checks if there is a gap in the unsafe queue and attempts to retrieve the missing payloads from an alt-sync method.
+// WARNING: This is only an outgoing signal, the blocks are not guaranteed to be retrieved.
+// Results are received through OnUnsafeL2Payload.
+func (s *Driver) checkForGapInUnsafeQueue(ctx context.Context) error {
 	// subtract genesis time from wall clock to get the time elapsed since genesis, and then divide that
 	// difference by the block time to get the expected L2 block number at the current time. If the
 	// unsafe head does not have this block number, then there is a gap in the queue.
 	wallClock := uint64(time.Now().Unix())
 	genesisTimestamp := s.config.Genesis.L2Time
+	if wallClock < genesisTimestamp {
+		s.log.Debug("nothing to sync, did not reach genesis L2 time yet", "genesis", genesisTimestamp)
+		return nil
+	}
 	wallClockGenesisDiff := wallClock - genesisTimestamp
-	expectedL2Block := wallClockGenesisDiff / s.config.BlockTime
+	// Note: round down, we should not request blocks into the future.
+	blocksSinceGenesis := wallClockGenesisDiff / s.config.BlockTime
+	expectedL2Block := s.config.Genesis.L2.Number + blocksSinceGenesis
 
 	start, end := s.derivation.GetUnsafeQueueGap(expectedL2Block)
-	size := end - start
-
 	// Check if there is a gap between the unsafe head and the expected L2 block number at the current time.
-	if size > 0 {
-		s.log.Warn("Gap in payload queue tip and expected unsafe chain detected", "start", start, "end", end, "size", size)
-		s.log.Info("Attempting to fetch missing payloads from backup RPC", "start", start, "end", end, "size", size)
-
-		// Attempt to fetch the missing payloads from the backup unsafe sync RPC concurrently.
-		// Concurrent requests are safe here due to the engine queue being a priority queue.
-		for blockNumber := start; blockNumber <= end; blockNumber++ {
-			select {
-			case s.L2SyncCl.FetchUnsafeBlock <- blockNumber:
-				// Do nothing- the block number was successfully sent into the channel
-			default:
-				return // If the channel is full, return and wait for the next iteration of the event loop
-			}
-		}
+	if end > start {
+		s.log.Debug("requesting missing unsafe L2 block range", "start", start, "end", end, "size", end-start)
+		return s.altSync.RequestL2Range(ctx, start, end)
 	}
+	return nil
 }

op-node/rollup/sync/start.go

@@ -109,6 +109,9 @@ func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain
 		return nil, fmt.Errorf("failed to fetch current L2 forkchoice state: %w", err)
 	}
 
+	lgr.Info("Loaded current L2 heads", "unsafe", result.Unsafe, "safe", result.Safe, "finalized", result.Finalized,
+		"unsafe_origin", result.Unsafe.L1Origin, "unsafe_origin", result.Safe.L1Origin)
+
 	// Remember original unsafe block to determine reorg depth
 	prevUnsafe := result.Unsafe
 
@@ -134,6 +137,7 @@ func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain
 				// Exit, find-sync start should start over, to move to an available L1 chain with block-by-number / not-found case.
 				return nil, fmt.Errorf("failed to retrieve L1 block: %w", err)
 			}
+			lgr.Info("Walking back L1Block by hash", "curr", l1Block, "next", b, "l2block", n)
 			l1Block = b
 			ahead = false
 		} else if l1Block == (eth.L1BlockRef{}) || n.L1Origin.Hash != l1Block.Hash {
@@ -145,9 +149,10 @@ func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain
 			}
 			l1Block = b
 			ahead = notFound
+			lgr.Info("Walking back L1Block by number", "curr", l1Block, "next", b, "l2block", n)
 		}
 
-		lgr.Trace("walking sync start", "number", n.Number)
+		lgr.Trace("walking sync start", "l2block", n)
 
 		// Don't walk past genesis. If we were at the L2 genesis, but could not find its L1 origin,
 		// the L2 chain is building on the wrong L1 branch.
@@ -201,6 +206,8 @@ func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain
 
 		// Don't traverse further than the finalized head to find a safe head
 		if n.Number == result.Finalized.Number {
+			lgr.Info("Hit finalized L2 head, returning immediately", "unsafe", result.Unsafe, "safe", result.Safe,
+				"finalized", result.Finalized, "unsafe_origin", result.Unsafe.L1Origin, "unsafe_origin", result.Safe.L1Origin)
 			result.Safe = n
 			return result, nil
 		}

op-node/service.go

@@ -136,6 +136,7 @@ func NewL2EndpointConfig(ctx *cli.Context, log log.Logger) (*node.L2EndpointConf
 func NewL2SyncEndpointConfig(ctx *cli.Context) *node.L2SyncEndpointConfig {
 	return &node.L2SyncEndpointConfig{
 		L2NodeAddr: ctx.GlobalString(flags.BackupL2UnsafeSyncRPC.Name),
+		TrustRPC:   ctx.GlobalBool(flags.BackupL2UnsafeSyncRPCTrustRPC.Name),
 	}
 }
 

op-node/sources/eth_client.go

@@ -13,6 +13,7 @@ import (
 	"context"
 	"fmt"
 	"math/big"
+	"time"
 
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
@@ -56,6 +57,11 @@ type EthClientConfig struct {
 
 	// RPCProviderKind is a hint at what type of RPC provider we are dealing with
 	RPCProviderKind RPCProviderKind
+
+	// Method reset duration defines how long we stick to available RPC methods,
+	// till we re-attempt the user-preferred methods.
+	// If this is 0 then the client does not fall back to less optimal but available methods.
+	MethodResetDuration time.Duration
 }
 
 func (c *EthClientConfig) Check() error {
@@ -118,9 +124,25 @@ type EthClient struct {
 	// This may be modified concurrently, but we don't lock since it's a single
 	// uint64 that's not critical (fine to miss or mix up a modification)
 	availableReceiptMethods ReceiptsFetchingMethod
+
+	// lastMethodsReset tracks when availableReceiptMethods was last reset.
+	// When receipt-fetching fails it falls back to available methods,
+	// but periodically it will try to reset to the preferred optimal methods.
+	lastMethodsReset time.Time
+
+	// methodResetDuration defines how long we take till we reset lastMethodsReset
+	methodResetDuration time.Duration
 }
 
 func (s *EthClient) PickReceiptsMethod(txCount uint64) ReceiptsFetchingMethod {
+	if now := time.Now(); now.Sub(s.lastMethodsReset) > s.methodResetDuration {
+		m := AvailableReceiptsFetchingMethods(s.provKind)
+		if s.availableReceiptMethods != m {
+			s.log.Warn("resetting back RPC preferences, please review RPC provider kind setting", "kind", s.provKind.String())
+		}
+		s.availableReceiptMethods = m
+		s.lastMethodsReset = now
+	}
 	return PickBestReceiptsFetchingMethod(s.provKind, s.availableReceiptMethods, txCount)
 }
 
@@ -128,7 +150,7 @@ func (s *EthClient) OnReceiptsMethodErr(m ReceiptsFetchingMethod, err error) {
 	if unusableMethod(err) {
 		// clear the bit of the method that errored
 		s.availableReceiptMethods &^= m
-		s.log.Warn("failed to use selected RPC method for receipt fetching, falling back to alternatives",
+		s.log.Warn("failed to use selected RPC method for receipt fetching, temporarily falling back to alternatives",
 			"provider_kind", s.provKind, "failed_method", m, "fallback", s.availableReceiptMethods, "err", err)
 	} else {
 		s.log.Debug("failed to use selected RPC method for receipt fetching, but method does appear to be available, so we continue to use it",
@@ -155,6 +177,8 @@ func NewEthClient(client client.RPC, log log.Logger, metrics caching.Metrics, co
 		headersCache:            caching.NewLRUCache(metrics, "headers", config.HeadersCacheSize),
 		payloadsCache:           caching.NewLRUCache(metrics, "payloads", config.PayloadsCacheSize),
 		availableReceiptMethods: AvailableReceiptsFetchingMethods(config.RPCProviderKind),
+		lastMethodsReset:        time.Now(),
+		methodResetDuration:     config.MethodResetDuration,
 	}, nil
 }
 
@@ -165,9 +189,39 @@ func (s *EthClient) SubscribeNewHead(ctx context.Context, ch chan<- *types.Heade
 	return s.client.EthSubscribe(ctx, ch, "newHeads")
 }
 
-func (s *EthClient) headerCall(ctx context.Context, method string, id any) (*HeaderInfo, error) {
+// rpcBlockID is an internal type to enforce header and block call results match the requested identifier
+type rpcBlockID interface {
+	// Arg translates the object into an RPC argument
+	Arg() any
+	// CheckID verifies a block/header result matches the requested block identifier
+	CheckID(id eth.BlockID) error
+}
+
+// hashID implements rpcBlockID for safe block-by-hash fetching
+type hashID common.Hash
+
+func (h hashID) Arg() any { return common.Hash(h) }
+func (h hashID) CheckID(id eth.BlockID) error {
+	if common.Hash(h) != id.Hash {
+		return fmt.Errorf("expected block hash %s but got block %s", common.Hash(h), id)
+	}
+	return nil
+}
+
+// numberID implements rpcBlockID for safe block-by-number fetching
+type numberID uint64
+
+func (n numberID) Arg() any { return hexutil.EncodeUint64(uint64(n)) }
+func (n numberID) CheckID(id eth.BlockID) error {
+	if uint64(n) != id.Number {
+		return fmt.Errorf("expected block number %d but got block %s", uint64(n), id)
+	}
+	return nil
+}
+
+func (s *EthClient) headerCall(ctx context.Context, method string, id rpcBlockID) (*HeaderInfo, error) {
 	var header *rpcHeader
-	err := s.client.CallContext(ctx, &header, method, id, false) // headers are just blocks without txs
+	err := s.client.CallContext(ctx, &header, method, id.Arg(), false) // headers are just blocks without txs
 	if err != nil {
 		return nil, err
 	}
@@ -178,13 +232,16 @@ func (s *EthClient) headerCall(ctx context.Context, method string, id any) (*Hea
 	if err != nil {
 		return nil, err
 	}
+	if err := id.CheckID(eth.ToBlockID(info)); err != nil {
+		return nil, fmt.Errorf("fetched block header does not match requested ID: %w", err)
+	}
 	s.headersCache.Add(info.Hash(), info)
 	return info, nil
 }
 
-func (s *EthClient) blockCall(ctx context.Context, method string, id any) (*HeaderInfo, types.Transactions, error) {
+func (s *EthClient) blockCall(ctx context.Context, method string, id rpcBlockID) (*HeaderInfo, types.Transactions, error) {
 	var block *rpcBlock
-	err := s.client.CallContext(ctx, &block, method, id, true)
+	err := s.client.CallContext(ctx, &block, method, id.Arg(), true)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -195,14 +252,17 @@ func (s *EthClient) blockCall(ctx context.Context, method string, id any) (*Head
 	if err != nil {
 		return nil, nil, err
 	}
+	if err := id.CheckID(eth.ToBlockID(info)); err != nil {
+		return nil, nil, fmt.Errorf("fetched block data does not match requested ID: %w", err)
+	}
 	s.headersCache.Add(info.Hash(), info)
 	s.transactionsCache.Add(info.Hash(), txs)
 	return info, txs, nil
 }
 
-func (s *EthClient) payloadCall(ctx context.Context, method string, id any) (*eth.ExecutionPayload, error) {
+func (s *EthClient) payloadCall(ctx context.Context, method string, id rpcBlockID) (*eth.ExecutionPayload, error) {
 	var block *rpcBlock
-	err := s.client.CallContext(ctx, &block, method, id, true)
+	err := s.client.CallContext(ctx, &block, method, id.Arg(), true)
 	if err != nil {
 		return nil, err
 	}
@@ -213,6 +273,9 @@ func (s *EthClient) payloadCall(ctx context.Context, method string, id any) (*et
 	if err != nil {
 		return nil, err
 	}
+	if err := id.CheckID(payload.ID()); err != nil {
+		return nil, fmt.Errorf("fetched payload does not match requested ID: %w", err)
+	}
 	s.payloadsCache.Add(payload.BlockHash, payload)
 	return payload, nil
 }
@@ -231,17 +294,17 @@ func (s *EthClient) InfoByHash(ctx context.Context, hash common.Hash) (eth.Block
 	if header, ok := s.headersCache.Get(hash); ok {
 		return header.(*HeaderInfo), nil
 	}
-	return s.headerCall(ctx, "eth_getBlockByHash", hash)
+	return s.headerCall(ctx, "eth_getBlockByHash", hashID(hash))
 }
 
 func (s *EthClient) InfoByNumber(ctx context.Context, number uint64) (eth.BlockInfo, error) {
 	// can't hit the cache when querying by number due to reorgs.
-	return s.headerCall(ctx, "eth_getBlockByNumber", hexutil.EncodeUint64(number))
+	return s.headerCall(ctx, "eth_getBlockByNumber", numberID(number))
 }
 
 func (s *EthClient) InfoByLabel(ctx context.Context, label eth.BlockLabel) (eth.BlockInfo, error) {
 	// can't hit the cache when querying the head due to reorgs / changes.
-	return s.headerCall(ctx, "eth_getBlockByNumber", string(label))
+	return s.headerCall(ctx, "eth_getBlockByNumber", label)
 }
 
 func (s *EthClient) InfoAndTxsByHash(ctx context.Context, hash common.Hash) (eth.BlockInfo, types.Transactions, error) {
@@ -250,32 +313,32 @@ func (s *EthClient) InfoAndTxsByHash(ctx context.Context, hash common.Hash) (eth
 			return header.(*HeaderInfo), txs.(types.Transactions), nil
 		}
 	}
-	return s.blockCall(ctx, "eth_getBlockByHash", hash)
+	return s.blockCall(ctx, "eth_getBlockByHash", hashID(hash))
 }
 
 func (s *EthClient) InfoAndTxsByNumber(ctx context.Context, number uint64) (eth.BlockInfo, types.Transactions, error) {
 	// can't hit the cache when querying by number due to reorgs.
-	return s.blockCall(ctx, "eth_getBlockByNumber", hexutil.EncodeUint64(number))
+	return s.blockCall(ctx, "eth_getBlockByNumber", numberID(number))
 }
 
 func (s *EthClient) InfoAndTxsByLabel(ctx context.Context, label eth.BlockLabel) (eth.BlockInfo, types.Transactions, error) {
 	// can't hit the cache when querying the head due to reorgs / changes.
-	return s.blockCall(ctx, "eth_getBlockByNumber", string(label))
+	return s.blockCall(ctx, "eth_getBlockByNumber", label)
 }
 
 func (s *EthClient) PayloadByHash(ctx context.Context, hash common.Hash) (*eth.ExecutionPayload, error) {
 	if payload, ok := s.payloadsCache.Get(hash); ok {
 		return payload.(*eth.ExecutionPayload), nil
 	}
-	return s.payloadCall(ctx, "eth_getBlockByHash", hash)
+	return s.payloadCall(ctx, "eth_getBlockByHash", hashID(hash))
 }
 
 func (s *EthClient) PayloadByNumber(ctx context.Context, number uint64) (*eth.ExecutionPayload, error) {
-	return s.payloadCall(ctx, "eth_getBlockByNumber", hexutil.EncodeUint64(number))
+	return s.payloadCall(ctx, "eth_getBlockByNumber", numberID(number))
 }
 
 func (s *EthClient) PayloadByLabel(ctx context.Context, label eth.BlockLabel) (*eth.ExecutionPayload, error) {
-	return s.payloadCall(ctx, "eth_getBlockByNumber", string(label))
+	return s.payloadCall(ctx, "eth_getBlockByNumber", label)
 }
 
 // FetchReceipts returns a block info and all of the receipts associated with transactions in the block.

op-node/sources/eth_client_test.go

@@ -140,3 +140,40 @@ func TestEthClient_InfoByNumber(t *testing.T) {
 	require.Equal(t, info, expectedInfo)
 	m.Mock.AssertExpectations(t)
 }
+
+func TestEthClient_WrongInfoByNumber(t *testing.T) {
+	m := new(mockRPC)
+	_, rhdr := randHeader()
+	rhdr2 := *rhdr
+	rhdr2.Number += 1
+	n := rhdr.Number
+	ctx := context.Background()
+	m.On("CallContext", ctx, new(*rpcHeader),
+		"eth_getBlockByNumber", []any{n.String(), false}).Run(func(args mock.Arguments) {
+		*args[1].(**rpcHeader) = &rhdr2
+	}).Return([]error{nil})
+	s, err := NewL1Client(m, nil, nil, L1ClientDefaultConfig(&rollup.Config{SeqWindowSize: 10}, true, RPCKindBasic))
+	require.NoError(t, err)
+	_, err = s.InfoByNumber(ctx, uint64(n))
+	require.Error(t, err, "cannot accept the wrong block")
+	m.Mock.AssertExpectations(t)
+}
+
+func TestEthClient_WrongInfoByHash(t *testing.T) {
+	m := new(mockRPC)
+	_, rhdr := randHeader()
+	rhdr2 := *rhdr
+	rhdr2.Root[0] += 1
+	rhdr2.Hash = rhdr2.computeBlockHash()
+	k := rhdr.Hash
+	ctx := context.Background()
+	m.On("CallContext", ctx, new(*rpcHeader),
+		"eth_getBlockByHash", []any{k, false}).Run(func(args mock.Arguments) {
+		*args[1].(**rpcHeader) = &rhdr2
+	}).Return([]error{nil})
+	s, err := NewL1Client(m, nil, nil, L1ClientDefaultConfig(&rollup.Config{SeqWindowSize: 10}, true, RPCKindBasic))
+	require.NoError(t, err)
+	_, err = s.InfoByHash(ctx, k)
+	require.Error(t, err, "cannot accept the wrong block")
+	m.Mock.AssertExpectations(t)
+}

op-node/sources/l1_client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"strings"
+	"time"
 
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
@@ -40,6 +41,7 @@ func L1ClientDefaultConfig(config *rollup.Config, trustRPC bool, kind RPCProvide
 			TrustRPC:              trustRPC,
 			MustBePostMerge:       false,
 			RPCProviderKind:       kind,
+			MethodResetDuration:   time.Minute,
 		},
 		// Not bounded by span, to cover find-sync-start range fully for speedy recovery after errors.
 		L1BlockRefsCacheSize: fullSpan,

op-node/sources/l2_client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"strings"
+	"time"
 
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
@@ -50,6 +51,7 @@ func L2ClientDefaultConfig(config *rollup.Config, trustRPC bool) *L2ClientConfig
 			TrustRPC:              trustRPC,
 			MustBePostMerge:       true,
 			RPCProviderKind:       RPCKindBasic,
+			MethodResetDuration:   time.Minute,
 		},
 		// Not bounded by span, to cover find-sync-start range fully for speedy recovery after errors.
 		L2BlockRefsCacheSize: fullSpan,

op-node/sources/receipts_test.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"math/rand"
 	"testing"
+	"time"
 
 	"github.com/ethereum-optimism/optimism/op-node/client"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
@@ -85,6 +86,7 @@ func (e *methodNotFoundError) Error() string {
 type ReceiptsTestCase struct {
 	name         string
 	providerKind RPCProviderKind
+	staticMethod bool
 	setup        func(t *testing.T) (*rpcBlock, []ReceiptsRequest)
 }
 
@@ -142,6 +144,10 @@ func (tc *ReceiptsTestCase) Run(t *testing.T) {
 		TrustRPC:              false,
 		MustBePostMerge:       false,
 		RPCProviderKind:       tc.providerKind,
+		MethodResetDuration:   time.Minute,
+	}
+	if tc.staticMethod { // if static, instantly reset, for fast clock-independent testing
+		testCfg.MethodResetDuration = 0
 	}
 	logger := testlog.Logger(t, log.LvlError)
 	ethCl, err := NewEthClient(client.NewBaseRPCClient(cl), logger, nil, testCfg)
@@ -226,6 +232,12 @@ func TestEthClient_FetchReceipts(t *testing.T) {
 			providerKind: RPCKindAlchemy,
 			setup:        fallbackCase(30, AlchemyGetTransactionReceipts),
 		},
+		{
+			name:         "alchemy sticky",
+			providerKind: RPCKindAlchemy,
+			staticMethod: true,
+			setup:        fallbackCase(30, AlchemyGetTransactionReceipts, AlchemyGetTransactionReceipts),
+		},
 		{
 			name:         "alchemy fallback 1",
 			providerKind: RPCKindAlchemy,

op-node/sources/sync_client.go

@@ -3,12 +3,17 @@ package sources
 import (
 	"context"
 	"errors"
+	"fmt"
+	"io"
 	"sync"
+	"time"
 
 	"github.com/ethereum-optimism/optimism/op-node/client"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/sources/caching"
+	"github.com/ethereum-optimism/optimism/op-service/backoff"
+
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/libp2p/go-libp2p/core/peer"
 )
@@ -18,23 +23,29 @@ var ErrNoUnsafeL2PayloadChannel = errors.New("unsafeL2Payloads channel must not
 // RpcSyncPeer is a mock PeerID for the RPC sync client.
 var RpcSyncPeer peer.ID = "ALT_RPC_SYNC"
 
+// receivePayload queues the received payload for processing.
+// This may return an error if there's no capacity for the payload.
 type receivePayload = func(ctx context.Context, from peer.ID, payload *eth.ExecutionPayload) error
 
-type SyncClientInterface interface {
+type RPCSync interface {
+	io.Closer
+	// Start starts an additional worker syncing job
 	Start() error
-	Close() error
-	fetchUnsafeBlockFromRpc(ctx context.Context, blockNumber uint64)
+	// RequestL2Range signals that the given range should be fetched, implementing the alt-sync interface.
+	RequestL2Range(ctx context.Context, start, end uint64) error
 }
 
 type SyncClient struct {
 	*L2Client
-	FetchUnsafeBlock chan uint64
-	done             chan struct{}
-	receivePayload   receivePayload
-	wg               sync.WaitGroup
-}
 
-var _ SyncClientInterface = (*SyncClient)(nil)
+	requests chan uint64
+
+	resCtx    context.Context
+	resCancel context.CancelFunc
+
+	receivePayload receivePayload
+	wg             sync.WaitGroup
+}
 
 type SyncClientConfig struct {
 	L2ClientConfig
@@ -51,41 +62,92 @@ func NewSyncClient(receiver receivePayload, client client.RPC, log log.Logger, m
 	if err != nil {
 		return nil, err
 	}
-
+	// This resource context is shared between all workers that may be started
+	resCtx, resCancel := context.WithCancel(context.Background())
 	return &SyncClient{
-		L2Client:         l2Client,
-		FetchUnsafeBlock: make(chan uint64, 128),
-		done:             make(chan struct{}),
-		receivePayload:   receiver,
+		L2Client:       l2Client,
+		resCtx:         resCtx,
+		resCancel:      resCancel,
+		requests:       make(chan uint64, 128),
+		receivePayload: receiver,
 	}, nil
 }
 
-// Start starts up the state loop.
-// The loop will have been started if err is not nil.
+// Start starts the syncing background work. This may not be called after Close().
 func (s *SyncClient) Start() error {
+	// TODO(CLI-3635): we can start multiple event loop runners as workers, to parallelize the work
 	s.wg.Add(1)
 	go s.eventLoop()
 	return nil
 }
 
-// Close sends a signal to the event loop to stop.
+// Close sends a signal to close all concurrent syncing work.
 func (s *SyncClient) Close() error {
-	s.done <- struct{}{}
+	s.resCancel()
 	s.wg.Wait()
 	return nil
 }
 
+func (s *SyncClient) RequestL2Range(ctx context.Context, start, end uint64) error {
+	// Drain previous requests now that we have new information
+	for len(s.requests) > 0 {
+		select { // in case requests is being read at the same time, don't block on draining it.
+		case <-s.requests:
+		default:
+			break
+		}
+	}
+
+	// TODO(CLI-3635): optimize the by-range fetching with the Engine API payloads-by-range method.
+
+	s.log.Info("Scheduling to fetch missing payloads from backup RPC", "start", start, "end", end, "size", end-start)
+
+	for i := start; i < end; i++ {
+		select {
+		case s.requests <- i:
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+	return nil
+}
+
 // eventLoop is the main event loop for the sync client.
 func (s *SyncClient) eventLoop() {
 	defer s.wg.Done()
 	s.log.Info("Starting sync client event loop")
 
+	backoffStrategy := &backoff.ExponentialStrategy{
+		Min:       1000,
+		Max:       20_000,
+		MaxJitter: 250,
+	}
+
 	for {
 		select {
-		case <-s.done:
+		case <-s.resCtx.Done():
+			s.log.Debug("Shutting down RPC sync worker")
 			return
-		case blockNumber := <-s.FetchUnsafeBlock:
-			s.fetchUnsafeBlockFromRpc(context.Background(), blockNumber)
+		case reqNum := <-s.requests:
+			err := backoff.DoCtx(s.resCtx, 5, backoffStrategy, func() error {
+				// Limit the maximum time for fetching payloads
+				ctx, cancel := context.WithTimeout(s.resCtx, time.Second*10)
+				defer cancel()
+				// We are only fetching one block at a time here.
+				return s.fetchUnsafeBlockFromRpc(ctx, reqNum)
+			})
+			if err != nil {
+				if err == s.resCtx.Err() {
+					return
+				}
+				s.log.Error("failed syncing L2 block via RPC", "err", err, "num", reqNum)
+				// Reschedule at end of queue
+				select {
+				case s.requests <- reqNum:
+				default:
+					// drop syncing job if we are too busy with sync jobs already.
+				}
+			}
 		}
 	}
 }
@@ -95,28 +157,22 @@ func (s *SyncClient) eventLoop() {
 //
 // Post Shanghai hardfork, the engine API's `PayloadBodiesByRange` method will be much more efficient, but for now,
 // the `eth_getBlockByNumber` method is more widely available.
-func (s *SyncClient) fetchUnsafeBlockFromRpc(ctx context.Context, blockNumber uint64) {
+func (s *SyncClient) fetchUnsafeBlockFromRpc(ctx context.Context, blockNumber uint64) error {
 	s.log.Info("Requesting unsafe payload from backup RPC", "block number", blockNumber)
 
 	payload, err := s.PayloadByNumber(ctx, blockNumber)
 	if err != nil {
-		s.log.Warn("Failed to convert block to execution payload", "block number", blockNumber, "err", err)
-		return
-	}
-
-	// Signature validation is not necessary here since the backup RPC is trusted.
-	if _, ok := payload.CheckBlockHash(); !ok {
-		s.log.Warn("Received invalid payload from backup RPC; invalid block hash", "payload", payload.ID())
-		return
+		return fmt.Errorf("failed to fetch payload by number (%d): %w", blockNumber, err)
 	}
+	// Note: the underlying RPC client used for syncing verifies the execution payload blockhash, if set to untrusted.
 
 	s.log.Info("Received unsafe payload from backup RPC", "payload", payload.ID())
 
 	// Send the retrieved payload to the `unsafeL2Payloads` channel.
 	if err = s.receivePayload(ctx, RpcSyncPeer, payload); err != nil {
-		s.log.Warn("Failed to send payload into the driver's unsafeL2Payloads channel", "payload", payload.ID(), "err", err)
-		return
+		return fmt.Errorf("failed to send payload %s into the driver's unsafeL2Payloads channel: %w", payload.ID(), err)
 	} else {
-		s.log.Info("Sent received payload into the driver's unsafeL2Payloads channel", "payload", payload.ID())
+		s.log.Debug("Sent received payload into the driver's unsafeL2Payloads channel", "payload", payload.ID())
+		return nil
 	}
 }

op-proposer/metrics/metrics.go

+package metrics
+
+import (
+	"context"
+
+	"github.com/ethereum-optimism/optimism/op-node/eth"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/prometheus/client_golang/prometheus"
+
+	opmetrics "github.com/ethereum-optimism/optimism/op-service/metrics"
+)
+
+const Namespace = "op_proposer"
+
+type Metricer interface {
+	RecordInfo(version string)
+	RecordUp()
+
+	// Records all L1 and L2 block events
+	opmetrics.RefMetricer
+
+	RecordL2BlocksProposed(l2ref eth.L2BlockRef)
+}
+
+type Metrics struct {
+	ns       string
+	registry *prometheus.Registry
+	factory  opmetrics.Factory
+
+	opmetrics.RefMetrics
+
+	Info prometheus.GaugeVec
+	Up   prometheus.Gauge
+}
+
+var _ Metricer = (*Metrics)(nil)
+
+func NewMetrics(procName string) *Metrics {
+	if procName == "" {
+		procName = "default"
+	}
+	ns := Namespace + "_" + procName
+
+	registry := opmetrics.NewRegistry()
+	factory := opmetrics.With(registry)
+
+	return &Metrics{
+		ns:       ns,
+		registry: registry,
+		factory:  factory,
+
+		RefMetrics: opmetrics.MakeRefMetrics(ns, factory),
+
+		Info: *factory.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: ns,
+			Name:      "info",
+			Help:      "Pseudo-metric tracking version and config info",
+		}, []string{
+			"version",
+		}),
+		Up: factory.NewGauge(prometheus.GaugeOpts{
+			Namespace: ns,
+			Name:      "up",
+			Help:      "1 if the op-proposer has finished starting up",
+		}),
+	}
+}
+
+func (m *Metrics) Serve(ctx context.Context, host string, port int) error {
+	return opmetrics.ListenAndServe(ctx, m.registry, host, port)
+}
+
+func (m *Metrics) StartBalanceMetrics(ctx context.Context,
+	l log.Logger, client *ethclient.Client, account common.Address) {
+	opmetrics.LaunchBalanceMetrics(ctx, l, m.registry, m.ns, client, account)
+}
+
+// RecordInfo sets a pseudo-metric that contains versioning and
+// config info for the op-proposer.
+func (m *Metrics) RecordInfo(version string) {
+	m.Info.WithLabelValues(version).Set(1)
+}
+
+// RecordUp sets the up metric to 1.
+func (m *Metrics) RecordUp() {
+	prometheus.MustRegister()
+	m.Up.Set(1)
+}
+
+const (
+	BlockProposed = "proposed"
+)
+
+// RecordL2BlocksProposed should be called when new L2 block is proposed
+func (m *Metrics) RecordL2BlocksProposed(l2ref eth.L2BlockRef) {
+	m.RecordL2Ref(BlockProposed, l2ref)
+}

op-proposer/metrics/noop.go

+package metrics
+
+import (
+	"github.com/ethereum-optimism/optimism/op-node/eth"
+	opmetrics "github.com/ethereum-optimism/optimism/op-service/metrics"
+)
+
+type noopMetrics struct{ opmetrics.NoopRefMetrics }
+
+var NoopMetrics Metricer = new(noopMetrics)
+
+func (*noopMetrics) RecordInfo(version string) {}
+func (*noopMetrics) RecordUp()                 {}
+
+func (*noopMetrics) RecordL2BlocksProposed(l2ref eth.L2BlockRef) {}

op-proposer/proposer/l2_output_submitter.go

@@ -24,9 +24,9 @@ import (
 	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/sources"
+	"github.com/ethereum-optimism/optimism/op-proposer/metrics"
 	opcrypto "github.com/ethereum-optimism/optimism/op-service/crypto"
 	oplog "github.com/ethereum-optimism/optimism/op-service/log"
-	opmetrics "github.com/ethereum-optimism/optimism/op-service/metrics"
 	oppprof "github.com/ethereum-optimism/optimism/op-service/pprof"
 	oprpc "github.com/ethereum-optimism/optimism/op-service/rpc"
 	"github.com/ethereum-optimism/optimism/op-service/txmgr"
@@ -49,9 +49,10 @@ func Main(version string, cliCtx *cli.Context) error {
 	}
 
 	l := oplog.NewLogger(cfg.LogConfig)
+	m := metrics.NewMetrics("default")
 	l.Info("Initializing L2 Output Submitter")
 
-	l2OutputSubmitter, err := NewL2OutputSubmitterFromCLIConfig(cfg, l)
+	l2OutputSubmitter, err := NewL2OutputSubmitterFromCLIConfig(cfg, l, m)
 	if err != nil {
 		l.Error("Unable to create the L2 Output Submitter", "error", err)
 		return err
@@ -78,17 +79,15 @@ func Main(version string, cliCtx *cli.Context) error {
 		}()
 	}
 
-	registry := opmetrics.NewRegistry()
 	metricsCfg := cfg.MetricsConfig
 	if metricsCfg.Enabled {
 		l.Info("starting metrics server", "addr", metricsCfg.ListenAddr, "port", metricsCfg.ListenPort)
 		go func() {
-			if err := opmetrics.ListenAndServe(ctx, registry, metricsCfg.ListenAddr, metricsCfg.ListenPort); err != nil {
+			if err := m.Serve(ctx, metricsCfg.ListenAddr, metricsCfg.ListenPort); err != nil {
 				l.Error("error starting metrics server", err)
 			}
 		}()
-		addr := l2OutputSubmitter.from
-		opmetrics.LaunchBalanceMetrics(ctx, l, registry, "", l2OutputSubmitter.l1Client, addr)
+		m.StartBalanceMetrics(ctx, l, l2OutputSubmitter.l1Client, l2OutputSubmitter.from)
 	}
 
 	rpcCfg := cfg.RPCConfig
@@ -98,6 +97,9 @@ func Main(version string, cliCtx *cli.Context) error {
 		return fmt.Errorf("error starting RPC server: %w", err)
 	}
 
+	m.RecordInfo(version)
+	m.RecordUp()
+
 	interruptChannel := make(chan os.Signal, 1)
 	signal.Notify(interruptChannel, []os.Signal{
 		os.Interrupt,
@@ -117,6 +119,7 @@ type L2OutputSubmitter struct {
 	wg    sync.WaitGroup
 	done  chan struct{}
 	log   log.Logger
+	metr  metrics.Metricer
 
 	ctx    context.Context
 	cancel context.CancelFunc
@@ -143,7 +146,7 @@ type L2OutputSubmitter struct {
 }
 
 // NewL2OutputSubmitterFromCLIConfig creates a new L2 Output Submitter given the CLI Config
-func NewL2OutputSubmitterFromCLIConfig(cfg CLIConfig, l log.Logger) (*L2OutputSubmitter, error) {
+func NewL2OutputSubmitterFromCLIConfig(cfg CLIConfig, l log.Logger, m metrics.Metricer) (*L2OutputSubmitter, error) {
 	signer, fromAddress, err := opcrypto.SignerFactoryFromConfig(l, cfg.PrivateKey, cfg.Mnemonic, cfg.L2OutputHDPath, cfg.SignerConfig)
 	if err != nil {
 		return nil, err
@@ -191,11 +194,11 @@ func NewL2OutputSubmitterFromCLIConfig(cfg CLIConfig, l log.Logger) (*L2OutputSu
 		SignerFnFactory:    signer,
 	}
 
-	return NewL2OutputSubmitter(proposerCfg, l)
+	return NewL2OutputSubmitter(proposerCfg, l, m)
 }
 
 // NewL2OutputSubmitter creates a new L2 Output Submitter
-func NewL2OutputSubmitter(cfg Config, l log.Logger) (*L2OutputSubmitter, error) {
+func NewL2OutputSubmitter(cfg Config, l log.Logger, m metrics.Metricer) (*L2OutputSubmitter, error) {
 	ctx, cancel := context.WithCancel(context.Background())
 
 	cCtx, cCancel := context.WithTimeout(ctx, defaultDialTimeout)
@@ -234,6 +237,7 @@ func NewL2OutputSubmitter(cfg Config, l log.Logger) (*L2OutputSubmitter, error)
 		log:    l,
 		ctx:    ctx,
 		cancel: cancel,
+		metr:   m,
 
 		l1Client:     cfg.L1Client,
 		rollupClient: cfg.RollupClient,
@@ -419,9 +423,9 @@ func (l *L2OutputSubmitter) loop() {
 				l.log.Error("Failed to send proposal transaction", "err", err)
 				cancel()
 				break
-			} else {
-				cancel()
 			}
+			l.metr.RecordL2BlocksProposed(output.BlockRef)
+			cancel()
 
 		case <-l.done:
 			return

ops-bedrock/docker-compose.yml

@@ -61,6 +61,8 @@ services:
       --p2p.listen.ip=0.0.0.0
       --p2p.listen.tcp=9003
       --p2p.listen.udp=9003
+      --p2p.scoring.peers=light
+      --p2p.ban.peers=true
       --snapshotlog.file=/op_log/snapshot.log
       --p2p.priv.path=/config/p2p-node-key.txt
       --metrics.enabled

ops/docker/ci-builder/Dockerfile

@@ -16,7 +16,7 @@ WORKDIR /opt/foundry
 # Only diff from upstream docker image is this clone instead
 # of COPY. We select a specific commit to use.
 RUN git clone https://github.com/foundry-rs/foundry.git . \
-    && git checkout 8f3fca9c608d58981daaffe11e7f8076644cb753
+    && git checkout da2392e58bb8a7fefeba46b40c4df1afad8ccd22
 
 RUN source $HOME/.profile && \
     cargo build --release && \

packages/contracts-bedrock/contracts/test/Bytes.t.sol

@@ -139,16 +139,20 @@ contract Bytes_slice_Test is Test {
         vm.assume(_length <= _input.length - _start);
 
         // Grab the free memory pointer before the slice operation
-        uint256 initPtr;
+        uint64 initPtr;
         assembly {
             initPtr := mload(0x40)
         }
+        uint64 expectedPtr = uint64(initPtr + 0x20 + ((_length + 0x1f) & ~uint256(0x1f)));
+
+        // Ensure that all memory outside of the expected range is safe.
+        vm.expectSafeMemory(initPtr, expectedPtr);
 
         // Slice the input bytes array from `_start` to `_start + _length`
         bytes memory slice = Bytes.slice(_input, _start, _length);
 
         // Grab the free memory pointer after the slice operation
-        uint256 finalPtr;
+        uint64 finalPtr;
         assembly {
             finalPtr := mload(0x40)
         }
@@ -165,10 +169,11 @@ contract Bytes_slice_Test is Test {
             // Note that we use a slightly less efficient, but equivalent method of rounding
             // up `_length` to the next multiple of 32 than is used in the `slice` function.
             // This is to diff test the method used in `slice`.
-            assertEq(finalPtr, initPtr + 0x20 + (((_length + 0x1F) >> 5) << 5));
+            uint64 _expectedPtr = uint64(initPtr + 0x20 + (((_length + 0x1F) >> 5) << 5));
+            assertEq(finalPtr, _expectedPtr);
 
             // Sanity check for equivalence of the rounding methods.
-            assertEq(((_length + 0x1F) >> 5) << 5, (_length + 0x1F) & ~uint256(0x1F));
+            assertEq(_expectedPtr, expectedPtr);
         }
 
         // The slice length should be equal to `_length`

packages/contracts-bedrock/deploy-config/getting-started.json

@@ -21,7 +21,7 @@
 
   "l2OutputOracleSubmissionInterval": 120,
   "l2OutputOracleStartingBlockNumber": 0,
-  "l2OutputOracleStartingTimestamp": "TIMESTAMP",
+  "l2OutputOracleStartingTimestamp": TIMESTAMP,
 
   "l2OutputOracleProposer": "PROPOSER",
   "l2OutputOracleChallenger": "ADMIN",

packages/contracts-bedrock/package.json

@@ -77,7 +77,7 @@
     "dotenv": "^16.0.0",
     "ds-test": "https://github.com/dapphub/ds-test.git#9310e879db8ba3ea6d5c6489a579118fd264a3f5",
     "ethereum-waffle": "^3.0.0",
-    "forge-std": "https://github.com/foundry-rs/forge-std.git#fd86115ed6aba8e234ee0fb86c12fe35eff0b2a0",
+    "forge-std": "https://github.com/foundry-rs/forge-std.git#46264e9788017fc74f9f58b7efa0bc6e1df6d410",
     "glob": "^7.1.6",
     "hardhat-deploy": "^0.11.4",
     "solhint": "^3.3.7",

yarn.lock

@@ -11471,14 +11471,14 @@ forever-agent@~0.6.1:
   resolved "https://registry.yarnpkg.com/forever-agent/-/forever-agent-0.6.1.tgz#fbc71f0c41adeb37f96c577ad1ed42d8fdacca91"
   integrity sha1-+8cfDEGt6zf5bFd60e1C2P2sypE=
 
+"forge-std@https://github.com/foundry-rs/forge-std.git#46264e9788017fc74f9f58b7efa0bc6e1df6d410":
+  version "1.5.2"
+  resolved "https://github.com/foundry-rs/forge-std.git#46264e9788017fc74f9f58b7efa0bc6e1df6d410"
+
 "forge-std@https://github.com/foundry-rs/forge-std.git#53331f4cb2e313466f72440f3e73af048c454d02":
   version "1.2.0"
   resolved "https://github.com/foundry-rs/forge-std.git#53331f4cb2e313466f72440f3e73af048c454d02"
 
-"forge-std@https://github.com/foundry-rs/forge-std.git#fd86115ed6aba8e234ee0fb86c12fe35eff0b2a0":
-  version "1.4.0"
-  resolved "https://github.com/foundry-rs/forge-std.git#fd86115ed6aba8e234ee0fb86c12fe35eff0b2a0"
-
 form-data@^2.2.0:
   version "2.5.1"
   resolved "https://registry.yarnpkg.com/form-data/-/form-data-2.5.1.tgz#f2cbec57b5e59e23716e128fe44d4e5dd23895f4"