Merge branch 'develop' into qbzzt/230321-stop-start

.changeset/cuddly-turkeys-burn.md

+---
+'@eth-optimism/sdk': patch
+---
+
+Have SDK automatically create Standard and ETH bridges when L1StandardBridge is provided.

.changeset/fresh-pots-move.md

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

.changeset/pink-chicken-hear.md

+---
+'@eth-optimism/contracts-bedrock': patch
+---
+
+Added a contsructor to the System Dictator

.circleci/config.yml

@@ -518,6 +518,10 @@ jobs:
           patterns: packages
       # Note: The below needs to be manually configured whenever we
       # add a new package to CI.
+      - run:
+          name: Check common-ts
+          command: npx depcheck
+          working_directory: packages/common-ts
       - run:
           name: Check contracts
           command: npx depcheck

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/.vuepress/config.js

@@ -166,6 +166,7 @@ module.exports = {
                 children: [
                   "/docs/build/tutorials/add-attr.md",
                   "/docs/build/tutorials/new-precomp.md",
+                  "/docs/build/tutorials/predeploys.md"
                 ]
               }  // End of tutorials
             ],

docs/op-stack/src/.vuepress/theme/components/PageMeta.vue

@@ -32,6 +32,11 @@
               <i class="fab fa-discord"></i> Discord community
             </a>
           </li>
+          <li>
+            <a href="https://wkf.ms/3XTdpLl" target="_blank" rel="noopener noreferrer">
+              <i class="far fa-comment-dots"></i> Get support for going live
+            </a>
+          </li>          
         </ul>
       </div>
     </div>

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
 

docs/op-stack/src/docs/build/tutorials/predeploys.md

+---
+title: Modifying Predeployed Contracts
+lang: en-US
+---
+
+::: warning 🚧 OP Stack Hacks are explicitly things that you can do with the OP Stack that are *not* currently intended for production use
+
+OP Stack Hacks are not for the faint of heart. You will not be able to receive significant developer support for OP Stack Hacks — be prepared to get your hands dirty and to work without support.
+
+:::
+
+
+OP Stack blockchains have a number of [predeployed contracts](https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/src/constants.ts) that provide important functionality. 
+Most of those contracts are proxies that can be upgraded using the `proxyAdminOwner` which was configured when the network was initially deployed.
+
+The predeploys are controlled from a predeploy called [`ProxyAdmin`](https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/contracts/universal/ProxyAdmin.sol), whose address is `0x4200000000000000000000000000000000000018`. 
+The function to call is [`upgrade(address,address)`](https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/contracts/universal/ProxyAdmin.sol#L211-L229).
+The first parameter is the proxy to upgrade, and the second is the address of a new implementation.
+
+For example, the legacy `L1BlockNumber` contract is at `0x420...013`. 
+To disable this function, we'll set the implementation to `0x00...00`.
+We do this using the [Foundry](https://book.getfoundry.sh/) command `cast`.
+
+1. We'll need several constants.
+
+    - Set these addresses as variables in your terminal.
+
+        ```sh
+        L1BLOCKNUM=0x4200000000000000000000000000000000000013
+        PROXY_ADMIN=0x4200000000000000000000000000000000000018
+        ZERO_ADDR=0x0000000000000000000000000000000000000000
+        ```
+
+    - Set `PRIVKEY` to the private key of your ADMIN account.
+
+    - Set `ETH_RPC_URL`. If you're on the computer that runs the blockchain, use this command.
+
+        ```sh
+        export ETH_RPC_URL=http://localhost:8545
+        ```
+
+1. Verify `L1BlockNumber` works correctly.
+   See that when you call the contract you get a block number, and twelve seconds later you get the next one (block time on L1 is twelve seconds).
+
+   ```sh
+   cast call $L1BLOCKNUM 'number()' | cast --to-dec
+   sleep 12 && cast call $L1BLOCKNUM 'number()' | cast --to-dec
+   ```
+
+1. Get the current implementation for the contract.
+
+   ```sh
+   L1BLOCKNUM_IMPLEMENTATION=`cast call $L1BLOCKNUM "implementation()" | sed 's/000000000000000000000000//'`
+   echo $L1BLOCKNUM_IMPLEMENTATION 
+   ```
+
+1. Change the implementation to the zero address   
+
+   ```sh
+   cast send --private-key $PRIVKEY $PROXY_ADMIN "upgrade(address,address)" $L1BLOCKNUM $ZERO_ADDR
+   ```
+
+1. See that the implementation is address zero, and that calling it fails.
+
+   ```sh
+   cast call $L1BLOCKNUM 'implementation()'
+   cast call $L1BLOCKNUM 'number()'
+   ```
+
+1. Fix the predeploy by returning it to the previous implementation, and verify it works. 
+
+
+   ```sh
+   cast send --private-key $PRIVKEY $PROXY_ADMIN "upgrade(address,address)" $L1BLOCKNUM $L1BLOCKNUM_IMPLEMENTATION
+   cast call $L1BLOCKNUM 'number()' | cast --to-dec
+   ```
\ No newline at end of file

op-batcher/Makefile

@@ -20,6 +20,7 @@ lint:
 	golangci-lint run -E goimports,sqlclosecheck,bodyclose,asciicheck,misspell,errorlint -e "errors.As" -e "errors.Is"
 
 fuzz:
+	go test -run NOTAREALTEST -v -fuzztime 10s -fuzz FuzzChannelConfig_CheckTimeout ./batcher
 	go test -run NOTAREALTEST -v -fuzztime 10s -fuzz FuzzDurationZero ./batcher
 	go test -run NOTAREALTEST -v -fuzztime 10s -fuzz FuzzDurationTimeoutMaxChannelDuration ./batcher
 	go test -run NOTAREALTEST -v -fuzztime 10s -fuzz FuzzDurationTimeoutZeroMaxChannelDuration ./batcher

op-batcher/batcher/channel_builder.go

@@ -12,8 +12,6 @@ import (
 )
 
 var (
-	ErrZeroMaxFrameSize      = errors.New("max frame size cannot be zero")
-	ErrSmallMaxFrameSize     = errors.New("max frame size cannot be less than 23")
 	ErrInvalidChannelTimeout = errors.New("channel timeout is less than the safety margin")
 	ErrInputTargetReached    = errors.New("target amount of input data reached")
 	ErrMaxFrameIndex         = errors.New("max frame index reached (uint16)")
@@ -83,15 +81,15 @@ func (cc *ChannelConfig) Check() error {
 	// will infinitely loop when trying to create frames in the
 	// [channelBuilder.OutputFrames] function.
 	if cc.MaxFrameSize == 0 {
-		return ErrZeroMaxFrameSize
+		return errors.New("max frame size cannot be zero")
 	}
 
-	// If the [MaxFrameSize] is set to < 23, the channel out
-	// will underflow the maxSize variable in the [derive.ChannelOut].
+	// If the [MaxFrameSize] is less than [FrameV0OverHeadSize], the channel
+	// out will underflow the maxSize variable in the [derive.ChannelOut].
 	// Since it is of type uint64, it will wrap around to a very large
 	// number, making the frame size extremely large.
-	if cc.MaxFrameSize < 23 {
-		return ErrSmallMaxFrameSize
+	if cc.MaxFrameSize < derive.FrameV0OverHeadSize {
+		return fmt.Errorf("max frame size %d is less than the minimum 23", cc.MaxFrameSize)
 	}
 
 	return nil

op-batcher/batcher/channel_manager_test.go

@@ -32,8 +32,7 @@ func TestPendingChannelTimeout(t *testing.T) {
 	require.False(t, timeout)
 
 	// Set the pending channel
-	err := m.ensurePendingChannel(eth.BlockID{})
-	require.NoError(t, err)
+	require.NoError(t, m.ensurePendingChannel(eth.BlockID{}))
 
 	// There are no confirmed transactions so
 	// the pending channel cannot be timed out
@@ -85,14 +84,10 @@ func TestChannelManagerReturnsErrReorg(t *testing.T) {
 		ParentHash: common.Hash{0xff},
 	}, nil, nil, nil, nil)
 
-	err := m.AddL2Block(a)
-	require.NoError(t, err)
-	err = m.AddL2Block(b)
-	require.NoError(t, err)
-	err = m.AddL2Block(c)
-	require.NoError(t, err)
-	err = m.AddL2Block(x)
-	require.ErrorIs(t, err, ErrReorg)
+	require.NoError(t, m.AddL2Block(a))
+	require.NoError(t, m.AddL2Block(b))
+	require.NoError(t, m.AddL2Block(c))
+	require.ErrorIs(t, m.AddL2Block(x), ErrReorg)
 
 	require.Equal(t, []*types.Block{a, b, c}, m.blocks)
 }
@@ -111,16 +106,14 @@ func TestChannelManagerReturnsErrReorgWhenDrained(t *testing.T) {
 	a := newMiniL2Block(0)
 	x := newMiniL2BlockWithNumberParent(0, big.NewInt(1), common.Hash{0xff})
 
-	err := m.AddL2Block(a)
-	require.NoError(t, err)
+	require.NoError(t, m.AddL2Block(a))
 
-	_, err = m.TxData(eth.BlockID{})
+	_, err := m.TxData(eth.BlockID{})
 	require.NoError(t, err)
 	_, err = m.TxData(eth.BlockID{})
 	require.ErrorIs(t, err, io.EOF)
 
-	err = m.AddL2Block(x)
-	require.ErrorIs(t, err, ErrReorg)
+	require.ErrorIs(t, m.AddL2Block(x), ErrReorg)
 }
 
 // TestChannelManagerNextTxData checks the nextTxData function.
@@ -136,8 +129,7 @@ func TestChannelManagerNextTxData(t *testing.T) {
 	// Set the pending channel
 	// The nextTxData function should still return EOF
 	// since the pending channel has no frames
-	err = m.ensurePendingChannel(eth.BlockID{})
-	require.NoError(t, err)
+	require.NoError(t, m.ensurePendingChannel(eth.BlockID{}))
 	returnedTxData, err = m.nextTxData()
 	require.ErrorIs(t, err, io.EOF)
 	require.Equal(t, txData{}, returnedTxData)
@@ -164,8 +156,10 @@ func TestChannelManagerNextTxData(t *testing.T) {
 	require.Equal(t, expectedTxData, m.pendingTransactions[expectedChannelID])
 }
 
-// TestClearChannelManager tests clearing the channel manager.
-func TestClearChannelManager(t *testing.T) {
+// TestChannelManager_Clear tests clearing the channel manager.
+func TestChannelManager_Clear(t *testing.T) {
+	require := require.New(t)
+
 	// Create a channel manager
 	log := testlog.Logger(t, log.LvlCrit)
 	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
@@ -176,15 +170,17 @@ func TestClearChannelManager(t *testing.T) {
 		ChannelTimeout: 10,
 		// Have to set the max frame size here otherwise the channel builder would not
 		// be able to output any frames
-		MaxFrameSize: 1,
+		MaxFrameSize:     24,
+		TargetFrameSize:  24,
+		ApproxComprRatio: 1.0,
 	})
 
 	// Channel Manager state should be empty by default
-	require.Empty(t, m.blocks)
-	require.Equal(t, common.Hash{}, m.tip)
-	require.Nil(t, m.pendingChannel)
-	require.Empty(t, m.pendingTransactions)
-	require.Empty(t, m.confirmedTransactions)
+	require.Empty(m.blocks)
+	require.Equal(common.Hash{}, m.tip)
+	require.Nil(m.pendingChannel)
+	require.Empty(m.pendingTransactions)
+	require.Empty(m.confirmedTransactions)
 
 	// Add a block to the channel manager
 	a, _ := derivetest.RandomL2Block(rng, 4)
@@ -193,28 +189,25 @@ func TestClearChannelManager(t *testing.T) {
 		Hash:   a.Hash(),
 		Number: a.NumberU64(),
 	}
-	err := m.AddL2Block(a)
-	require.NoError(t, err)
+	require.NoError(m.AddL2Block(a))
 
 	// Make sure there is a channel builder
-	err = m.ensurePendingChannel(l1BlockID)
-	require.NoError(t, err)
-	require.NotNil(t, m.pendingChannel)
-	require.Equal(t, 0, len(m.confirmedTransactions))
+	require.NoError(m.ensurePendingChannel(l1BlockID))
+	require.NotNil(m.pendingChannel)
+	require.Len(m.confirmedTransactions, 0)
 
 	// Process the blocks
 	// We should have a pending channel with 1 frame
 	// and no more blocks since processBlocks consumes
 	// the list
-	err = m.processBlocks()
-	require.NoError(t, err)
-	err = m.pendingChannel.OutputFrames()
-	require.NoError(t, err)
-	_, err = m.nextTxData()
-	require.NoError(t, err)
-	require.Equal(t, 0, len(m.blocks))
-	require.Equal(t, newL1Tip, m.tip)
-	require.Equal(t, 1, len(m.pendingTransactions))
+	require.NoError(m.processBlocks())
+	require.NoError(m.pendingChannel.co.Flush())
+	require.NoError(m.pendingChannel.OutputFrames())
+	_, err := m.nextTxData()
+	require.NoError(err)
+	require.Len(m.blocks, 0)
+	require.Equal(newL1Tip, m.tip)
+	require.Len(m.pendingTransactions, 1)
 
 	// Add a new block so we can test clearing
 	// the channel manager with a full state
@@ -222,20 +215,19 @@ func TestClearChannelManager(t *testing.T) {
 		Number:     big.NewInt(1),
 		ParentHash: a.Hash(),
 	}, nil, nil, nil, nil)
-	err = m.AddL2Block(b)
-	require.NoError(t, err)
-	require.Equal(t, 1, len(m.blocks))
-	require.Equal(t, b.Hash(), m.tip)
+	require.NoError(m.AddL2Block(b))
+	require.Len(m.blocks, 1)
+	require.Equal(b.Hash(), m.tip)
 
 	// Clear the channel manager
 	m.Clear()
 
 	// Check that the entire channel manager state cleared
-	require.Empty(t, m.blocks)
-	require.Equal(t, common.Hash{}, m.tip)
-	require.Nil(t, m.pendingChannel)
-	require.Empty(t, m.pendingTransactions)
-	require.Empty(t, m.confirmedTransactions)
+	require.Empty(m.blocks)
+	require.Equal(common.Hash{}, m.tip)
+	require.Nil(m.pendingChannel)
+	require.Empty(m.pendingTransactions)
+	require.Empty(m.confirmedTransactions)
 }
 
 // TestChannelManagerTxConfirmed checks the [ChannelManager.TxConfirmed] function.
@@ -251,8 +243,7 @@ func TestChannelManagerTxConfirmed(t *testing.T) {
 
 	// Let's add a valid pending transaction to the channel manager
 	// So we can demonstrate that TxConfirmed's correctness
-	err := m.ensurePendingChannel(eth.BlockID{})
-	require.NoError(t, err)
+	require.NoError(t, m.ensurePendingChannel(eth.BlockID{}))
 	channelID := m.pendingChannel.ID()
 	frame := frameData{
 		data: []byte{},
@@ -270,7 +261,7 @@ func TestChannelManagerTxConfirmed(t *testing.T) {
 	require.Equal(t, expectedTxData, returnedTxData)
 	require.Equal(t, 0, m.pendingChannel.NumFrames())
 	require.Equal(t, expectedTxData, m.pendingTransactions[expectedChannelID])
-	require.Equal(t, 1, len(m.pendingTransactions))
+	require.Len(t, m.pendingTransactions, 1)
 
 	// An unknown pending transaction should not be marked as confirmed
 	// and should not be removed from the pending transactions map
@@ -281,14 +272,14 @@ func TestChannelManagerTxConfirmed(t *testing.T) {
 	blockID := eth.BlockID{Number: 0, Hash: common.Hash{0x69}}
 	m.TxConfirmed(unknownTxID, blockID)
 	require.Empty(t, m.confirmedTransactions)
-	require.Equal(t, 1, len(m.pendingTransactions))
+	require.Len(t, m.pendingTransactions, 1)
 
 	// Now let's mark the pending transaction as confirmed
 	// and check that it is removed from the pending transactions map
 	// and added to the confirmed transactions map
 	m.TxConfirmed(expectedChannelID, blockID)
 	require.Empty(t, m.pendingTransactions)
-	require.Equal(t, 1, len(m.confirmedTransactions))
+	require.Len(t, m.confirmedTransactions, 1)
 	require.Equal(t, blockID, m.confirmedTransactions[expectedChannelID])
 }
 
@@ -300,8 +291,7 @@ func TestChannelManagerTxFailed(t *testing.T) {
 
 	// Let's add a valid pending transaction to the channel
 	// manager so we can demonstrate correctness
-	err := m.ensurePendingChannel(eth.BlockID{})
-	require.NoError(t, err)
+	require.NoError(t, m.ensurePendingChannel(eth.BlockID{}))
 	channelID := m.pendingChannel.ID()
 	frame := frameData{
 		data: []byte{},
@@ -319,7 +309,7 @@ func TestChannelManagerTxFailed(t *testing.T) {
 	require.Equal(t, expectedTxData, returnedTxData)
 	require.Equal(t, 0, m.pendingChannel.NumFrames())
 	require.Equal(t, expectedTxData, m.pendingTransactions[expectedChannelID])
-	require.Equal(t, 1, len(m.pendingTransactions))
+	require.Len(t, m.pendingTransactions, 1)
 
 	// Trying to mark an unknown pending transaction as failed
 	// shouldn't modify state
@@ -348,8 +338,7 @@ func TestChannelManager_TxResend(t *testing.T) {
 
 	a, _ := derivetest.RandomL2Block(rng, 4)
 
-	err := m.AddL2Block(a)
-	require.NoError(err)
+	require.NoError(m.AddL2Block(a))
 
 	txdata0, err := m.TxData(eth.BlockID{})
 	require.NoError(err)

op-batcher/batcher/config.go

@@ -110,6 +110,14 @@ type CLIConfig struct {
 
 	/* Optional Params */
 
+	// TxManagerTimeout is the max amount of time to wait for the [txmgr].
+	// This will default to: 10 * time.Minute.
+	TxManagerTimeout time.Duration
+
+	// OfflineGasEstimation specifies whether the batcher should calculate
+	// gas estimations offline using the [core.IntrinsicGas] function.
+	OfflineGasEstimation bool
+
 	// MaxL1TxSize is the maximum size of a batch tx submitted to L1.
 	MaxL1TxSize uint64
 
@@ -168,6 +176,8 @@ func NewConfig(ctx *cli.Context) CLIConfig {
 		ResubmissionTimeout:       ctx.GlobalDuration(flags.ResubmissionTimeoutFlag.Name),
 
 		/* Optional Flags */
+		OfflineGasEstimation: ctx.GlobalBool(flags.OfflineGasEstimationFlag.Name),
+		TxManagerTimeout:     ctx.GlobalDuration(flags.TxManagerTimeoutFlag.Name),
 		MaxChannelDuration:   ctx.GlobalUint64(flags.MaxChannelDurationFlag.Name),
 		MaxL1TxSize:          ctx.GlobalUint64(flags.MaxL1TxSizeBytesFlag.Name),
 		TargetL1TxSize:       ctx.GlobalUint64(flags.TargetL1TxSizeBytesFlag.Name),

op-batcher/batcher/driver.go

@@ -15,6 +15,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
 	opcrypto "github.com/ethereum-optimism/optimism/op-service/crypto"
 	"github.com/ethereum-optimism/optimism/op-service/txmgr"
+	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/log"
 )
@@ -24,7 +25,7 @@ import (
 type BatchSubmitter struct {
 	Config // directly embed the config + sources
 
-	txMgr *TransactionManager
+	txMgr txmgr.TxManager
 	wg    sync.WaitGroup
 	done  chan struct{}
 
@@ -79,6 +80,7 @@ func NewBatchSubmitterFromCLIConfig(cfg CLIConfig, l log.Logger, m metrics.Metri
 		NumConfirmations:          cfg.NumConfirmations,
 		SafeAbortNonceTooLowCount: cfg.SafeAbortNonceTooLowCount,
 		From:                      fromAddress,
+		ChainID:                   rcfg.L1ChainID,
 		Signer:                    signer(rcfg.L1ChainID),
 	}
 
@@ -125,9 +127,7 @@ func NewBatchSubmitter(ctx context.Context, cfg Config, l log.Logger, m metrics.
 
 	return &BatchSubmitter{
 		Config: cfg,
-		txMgr: NewTransactionManager(l,
-			cfg.TxManagerConfig, cfg.Rollup.BatchInboxAddress, cfg.Rollup.L1ChainID,
-			cfg.From, cfg.L1Client),
+		txMgr:  txmgr.NewSimpleTxManager("batcher", l, cfg.TxManagerConfig, cfg.L1Client),
 		state:  NewChannelManager(l, m, cfg.Channel),
 	}, nil
 
@@ -226,7 +226,7 @@ func (l *BatchSubmitter) loadBlocksIntoState(ctx context.Context) {
 
 // loadBlockIntoState fetches & stores a single block into `state`. It returns the block it loaded.
 func (l *BatchSubmitter) loadBlockIntoState(ctx context.Context, blockNumber uint64) (*types.Block, error) {
-	ctx, cancel := context.WithTimeout(ctx, networkTimeout)
+	ctx, cancel := context.WithTimeout(ctx, txManagerTimeout)
 	defer cancel()
 	block, err := l.L2Client.BlockByNumber(ctx, new(big.Int).SetUint64(blockNumber))
 	if err != nil {
@@ -244,7 +244,7 @@ func (l *BatchSubmitter) loadBlockIntoState(ctx context.Context, blockNumber uin
 // calculateL2BlockRangeToStore determines the range (start,end] that should be loaded into the local state.
 // It also takes care of initializing some local state (i.e. will modify l.lastStoredBlock in certain conditions)
 func (l *BatchSubmitter) calculateL2BlockRangeToStore(ctx context.Context) (eth.BlockID, eth.BlockID, error) {
-	childCtx, cancel := context.WithTimeout(ctx, networkTimeout)
+	childCtx, cancel := context.WithTimeout(ctx, txManagerTimeout)
 	defer cancel()
 	syncStatus, err := l.RollupNode.SyncStatus(childCtx)
 	// Ensure that we have the sync status
@@ -312,8 +312,9 @@ func (l *BatchSubmitter) loop() {
 					l.log.Error("unable to get tx data", "err", err)
 					break
 				}
+
 				// Record TX Status
-				if receipt, err := l.txMgr.SendTransaction(l.ctx, txdata.Bytes()); err != nil {
+				if receipt, err := l.SendTransaction(l.ctx, txdata.Bytes()); err != nil {
 					l.recordFailedTx(txdata.ID(), err)
 				} else {
 					l.recordConfirmedTx(txdata.ID(), receipt)
@@ -335,6 +336,46 @@ func (l *BatchSubmitter) loop() {
 	}
 }
 
+const networkTimeout = 2 * time.Second // How long a single network request can take. TODO: put in a config somewhere
+
+// fix(refcell):
+// combined with above, these config variables should also be replicated in the op-proposer
+// along with op-proposer changes to include the updated tx manager
+const txManagerTimeout = 2 * time.Minute // How long the tx manager can take to send a transaction.
+
+// SendTransaction creates & submits a transaction to the batch inbox address with the given `data`.
+// It currently uses the underlying `txmgr` to handle transaction sending & price management.
+// This is a blocking method. It should not be called concurrently.
+func (l *BatchSubmitter) SendTransaction(ctx context.Context, data []byte) (*types.Receipt, error) {
+	// Do the gas estimation offline. A value of 0 will cause the [txmgr] to estimate the gas limit.
+	intrinsicGas, err := core.IntrinsicGas(data, nil, false, true, true, false)
+	if err != nil {
+		return nil, fmt.Errorf("failed to calculate intrinsic gas: %w", err)
+	}
+
+	// Create the transaction
+	tx, err := l.txMgr.CraftTx(ctx, txmgr.TxCandidate{
+		To:       l.Rollup.BatchInboxAddress,
+		TxData:   data,
+		From:     l.From,
+		GasLimit: intrinsicGas,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to create tx: %w", err)
+	}
+
+	// Send the transaction through the txmgr
+	ctx, cancel := context.WithTimeout(ctx, txManagerTimeout)
+	defer cancel()
+	if receipt, err := l.txMgr.Send(ctx, tx); err != nil {
+		l.log.Warn("unable to publish tx", "err", err, "data_size", len(data))
+		return nil, err
+	} else {
+		l.log.Info("tx successfully published", "tx_hash", receipt.TxHash, "data_size", len(data))
+		return receipt, nil
+	}
+}
+
 func (l *BatchSubmitter) recordL1Tip(l1tip eth.L1BlockRef) {
 	if l.lastL1Tip == l1tip {
 		return

op-batcher/batcher/driver_test.go

+package batcher
+
+import (
+	"context"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
+
+	"github.com/ethereum-optimism/optimism/op-node/rollup"
+	"github.com/ethereum-optimism/optimism/op-node/testlog"
+	"github.com/ethereum-optimism/optimism/op-service/txmgr"
+	"github.com/ethereum-optimism/optimism/op-service/txmgr/mocks"
+)
+
+// TestBatchSubmitter_SendTransaction tests the driver's
+// [SendTransaction] external facing function.
+func TestBatchSubmitter_SendTransaction(t *testing.T) {
+	log := testlog.Logger(t, log.LvlCrit)
+	txMgr := mocks.TxManager{}
+	batcherInboxAddress := common.HexToAddress("0x42000000000000000000000000000000000000ff")
+	chainID := big.NewInt(1)
+	sender := common.HexToAddress("0xdeadbeef")
+	bs := BatchSubmitter{
+		Config: Config{
+			log:  log,
+			From: sender,
+			Rollup: &rollup.Config{
+				L1ChainID:         chainID,
+				BatchInboxAddress: batcherInboxAddress,
+			},
+		},
+		txMgr: &txMgr,
+	}
+	txData := []byte{0x00, 0x01, 0x02}
+
+	gasTipCap := big.NewInt(136)
+	gasFeeCap := big.NewInt(137)
+	gas := uint64(1337)
+
+	// Candidate gas should be calculated with [core.IntrinsicGas]
+	intrinsicGas, err := core.IntrinsicGas(txData, nil, false, true, true, false)
+	require.NoError(t, err)
+	candidate := txmgr.TxCandidate{
+		To:       batcherInboxAddress,
+		TxData:   txData,
+		From:     sender,
+		GasLimit: intrinsicGas,
+	}
+
+	tx := types.NewTx(&types.DynamicFeeTx{
+		ChainID:   chainID,
+		Nonce:     0,
+		GasTipCap: gasTipCap,
+		GasFeeCap: gasFeeCap,
+		Gas:       gas,
+		To:        &batcherInboxAddress,
+		Data:      txData,
+	})
+	txHash := tx.Hash()
+
+	expectedReceipt := types.Receipt{
+		Type:              1,
+		PostState:         []byte{},
+		Status:            uint64(1),
+		CumulativeGasUsed: gas,
+		TxHash:            txHash,
+		GasUsed:           gas,
+	}
+
+	txMgr.On("CraftTx", mock.Anything, candidate).Return(tx, nil)
+	txMgr.On("Send", mock.Anything, tx).Return(&expectedReceipt, nil)
+
+	receipt, err := bs.SendTransaction(context.Background(), tx.Data())
+	require.NoError(t, err)
+	require.Equal(t, receipt, &expectedReceipt)
+}

op-batcher/batcher/txmgr.go

-package batcher
-
-import (
-	"context"
-	"fmt"
-	"math/big"
-	"time"
-
-	"github.com/ethereum-optimism/optimism/op-service/txmgr"
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/ethclient"
-	"github.com/ethereum/go-ethereum/log"
-	"github.com/ethereum/go-ethereum/params"
-
-	opcrypto "github.com/ethereum-optimism/optimism/op-service/crypto"
-)
-
-const networkTimeout = 2 * time.Second // How long a single network request can take. TODO: put in a config somewhere
-
-// TransactionManager wraps the simple txmgr package to make it easy to send & wait for transactions
-type TransactionManager struct {
-	// Config
-	batchInboxAddress common.Address
-	senderAddress     common.Address
-	chainID           *big.Int
-	// Outside world
-	txMgr    txmgr.TxManager
-	l1Client *ethclient.Client
-	signerFn opcrypto.SignerFn
-	log      log.Logger
-}
-
-func NewTransactionManager(log log.Logger, txMgrConfg txmgr.Config, batchInboxAddress common.Address, chainID *big.Int, senderAddress common.Address, l1Client *ethclient.Client) *TransactionManager {
-	t := &TransactionManager{
-		batchInboxAddress: batchInboxAddress,
-		senderAddress:     senderAddress,
-		chainID:           chainID,
-		txMgr:             txmgr.NewSimpleTxManager("batcher", log, txMgrConfg, l1Client),
-		l1Client:          l1Client,
-		signerFn:          txMgrConfg.Signer,
-		log:               log,
-	}
-	return t
-}
-
-// SendTransaction creates & submits a transaction to the batch inbox address with the given `data`.
-// It currently uses the underlying `txmgr` to handle transaction sending & price management.
-// This is a blocking method. It should not be called concurrently.
-// TODO: where to put concurrent transaction handling logic.
-func (t *TransactionManager) SendTransaction(ctx context.Context, data []byte) (*types.Receipt, error) {
-	tx, err := t.CraftTx(ctx, data)
-	if err != nil {
-		return nil, fmt.Errorf("failed to create tx: %w", err)
-	}
-
-	ctx, cancel := context.WithTimeout(ctx, 10*time.Minute) // TODO: Select a timeout that makes sense here.
-	defer cancel()
-	if receipt, err := t.txMgr.Send(ctx, tx); err != nil {
-		t.log.Warn("unable to publish tx", "err", err, "data_size", len(data))
-		return nil, err
-	} else {
-		t.log.Info("tx successfully published", "tx_hash", receipt.TxHash, "data_size", len(data))
-		return receipt, nil
-	}
-}
-
-// calcGasTipAndFeeCap queries L1 to determine what a suitable miner tip & basefee limit would be for timely inclusion
-func (t *TransactionManager) calcGasTipAndFeeCap(ctx context.Context) (gasTipCap *big.Int, gasFeeCap *big.Int, err error) {
-	childCtx, cancel := context.WithTimeout(ctx, networkTimeout)
-	gasTipCap, err = t.l1Client.SuggestGasTipCap(childCtx)
-	cancel()
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to get suggested gas tip cap: %w", err)
-	}
-
-	if gasTipCap == nil {
-		t.log.Warn("unexpected unset gasTipCap, using default 2 gwei")
-		gasTipCap = new(big.Int).SetUint64(params.GWei * 2)
-	}
-
-	childCtx, cancel = context.WithTimeout(ctx, networkTimeout)
-	head, err := t.l1Client.HeaderByNumber(childCtx, nil)
-	cancel()
-	if err != nil || head == nil {
-		return nil, nil, fmt.Errorf("failed to get L1 head block for fee cap: %w", err)
-	}
-	if head.BaseFee == nil {
-		return nil, nil, fmt.Errorf("failed to get L1 basefee in block %d for fee cap", head.Number)
-	}
-	gasFeeCap = txmgr.CalcGasFeeCap(head.BaseFee, gasTipCap)
-
-	return gasTipCap, gasFeeCap, nil
-}
-
-// CraftTx creates the signed transaction to the batchInboxAddress.
-// It queries L1 for the current fee market conditions as well as for the nonce.
-// NOTE: This method SHOULD NOT publish the resulting transaction.
-func (t *TransactionManager) CraftTx(ctx context.Context, data []byte) (*types.Transaction, error) {
-	gasTipCap, gasFeeCap, err := t.calcGasTipAndFeeCap(ctx)
-	if err != nil {
-		return nil, err
-	}
-
-	childCtx, cancel := context.WithTimeout(ctx, networkTimeout)
-	nonce, err := t.l1Client.NonceAt(childCtx, t.senderAddress, nil)
-	cancel()
-	if err != nil {
-		return nil, fmt.Errorf("failed to get nonce: %w", err)
-	}
-
-	rawTx := &types.DynamicFeeTx{
-		ChainID:   t.chainID,
-		Nonce:     nonce,
-		To:        &t.batchInboxAddress,
-		GasTipCap: gasTipCap,
-		GasFeeCap: gasFeeCap,
-		Data:      data,
-	}
-	t.log.Info("creating tx", "to", rawTx.To, "from", t.senderAddress)
-
-	gas, err := core.IntrinsicGas(rawTx.Data, nil, false, true, true, false)
-	if err != nil {
-		return nil, fmt.Errorf("failed to calculate intrinsic gas: %w", err)
-	}
-	rawTx.Gas = gas
-
-	ctx, cancel = context.WithTimeout(ctx, networkTimeout)
-	defer cancel()
-	tx := types.NewTx(rawTx)
-	return t.signerFn(ctx, t.senderAddress, tx)
-}

op-batcher/flags/flags.go

 package flags
 
 import (
+	"time"
+
 	"github.com/urfave/cli"
 
 	"github.com/ethereum-optimism/optimism/op-batcher/rpc"
@@ -74,7 +76,17 @@ var (
 	}
 
 	/* Optional flags */
-
+	OfflineGasEstimationFlag = cli.BoolFlag{
+		Name:   "offline-gas-estimation",
+		Usage:  "Whether to use offline gas estimation",
+		EnvVar: opservice.PrefixEnvVar(envVarPrefix, "OFFLINE_GAS_ESTIMATION"),
+	}
+	TxManagerTimeoutFlag = cli.DurationFlag{
+		Name:   "tx-manager-timeout",
+		Usage:  "Maximum duration to wait for L1 transactions, including resubmissions",
+		Value:  10 * time.Minute,
+		EnvVar: opservice.PrefixEnvVar(envVarPrefix, "TX_MANAGER_TIMEOUT"),
+	}
 	MaxChannelDurationFlag = cli.Uint64Flag{
 		Name:   "max-channel-duration",
 		Usage:  "The maximum duration of L1-blocks to keep a channel open. 0 to disable.",
@@ -141,6 +153,8 @@ var requiredFlags = []cli.Flag{
 }
 
 var optionalFlags = []cli.Flag{
+	OfflineGasEstimationFlag,
+	TxManagerTimeoutFlag,
 	MaxChannelDurationFlag,
 	MaxL1TxSizeBytesFlag,
 	TargetL1TxSizeBytesFlag,

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-chain-ops/ether/migrate_test.go

 package ether
 
 import (
-	"fmt"
 	"math/big"
 	"math/rand"
 	"testing"
 
+	"github.com/ethereum-optimism/optimism/op-chain-ops/util"
+
 	"github.com/ethereum-optimism/optimism/op-bindings/predeploys"
 
 	"github.com/ethereum-optimism/optimism/op-chain-ops/crossdomain"
@@ -190,7 +191,7 @@ func TestMigrateBalances(t *testing.T) {
 	}
 }
 
-func makeLegacyETH(t *testing.T, totalSupply *big.Int, balances map[common.Address]*big.Int, allowances map[common.Address]common.Address) (*state.StateDB, DBFactory) {
+func makeLegacyETH(t *testing.T, totalSupply *big.Int, balances map[common.Address]*big.Int, allowances map[common.Address]common.Address) (*state.StateDB, util.DBFactory) {
 	memDB := rawdb.NewMemoryDatabase()
 	db, err := state.New(common.Hash{}, state.NewDatabaseWithConfig(memDB, &trie.Config{
 		Preimages: true,
@@ -283,85 +284,6 @@ func TestMigrateBalancesRandomMissing(t *testing.T) {
 	}
 }
 
-func TestPartitionKeyspace(t *testing.T) {
-	tests := []struct {
-		i        int
-		count    int
-		expected [2]common.Hash
-	}{
-		{
-			i:     0,
-			count: 1,
-			expected: [2]common.Hash{
-				common.HexToHash("0x00"),
-				common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
-			},
-		},
-		{
-			i:     0,
-			count: 2,
-			expected: [2]common.Hash{
-				common.HexToHash("0x00"),
-				common.HexToHash("0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
-			},
-		},
-		{
-			i:     1,
-			count: 2,
-			expected: [2]common.Hash{
-				common.HexToHash("0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
-				common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
-			},
-		},
-		{
-			i:     0,
-			count: 3,
-			expected: [2]common.Hash{
-				common.HexToHash("0x00"),
-				common.HexToHash("0x5555555555555555555555555555555555555555555555555555555555555555"),
-			},
-		},
-		{
-			i:     1,
-			count: 3,
-			expected: [2]common.Hash{
-				common.HexToHash("0x5555555555555555555555555555555555555555555555555555555555555555"),
-				common.HexToHash("0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
-			},
-		},
-		{
-			i:     2,
-			count: 3,
-			expected: [2]common.Hash{
-				common.HexToHash("0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
-				common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
-			},
-		},
-	}
-	for _, tt := range tests {
-		t.Run(fmt.Sprintf("i %d, count %d", tt.i, tt.count), func(t *testing.T) {
-			start, end := PartitionKeyspace(tt.i, tt.count)
-			require.Equal(t, tt.expected[0], start)
-			require.Equal(t, tt.expected[1], end)
-		})
-	}
-
-	t.Run("panics on invalid i or count", func(t *testing.T) {
-		require.Panics(t, func() {
-			PartitionKeyspace(1, 1)
-		})
-		require.Panics(t, func() {
-			PartitionKeyspace(-1, 1)
-		})
-		require.Panics(t, func() {
-			PartitionKeyspace(0, -1)
-		})
-		require.Panics(t, func() {
-			PartitionKeyspace(-1, -1)
-		})
-	})
-}
-
 func randAddr(t *testing.T) common.Address {
 	var addr common.Address
 	_, err := rand.Read(addr[:])

op-chain-ops/util/state_iterator.go

+package util
+
+import (
+	"fmt"
+	"math/big"
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+var (
+	// maxSlot is the maximum possible storage slot.
+	maxSlot = common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")
+)
+
+type DBFactory func() (*state.StateDB, error)
+
+type StateCallback func(db *state.StateDB, key, value common.Hash) error
+
+func IterateState(dbFactory DBFactory, address common.Address, cb StateCallback, workers int) error {
+	if workers <= 0 {
+		panic("workers must be greater than 0")
+	}
+
+	// WaitGroup to wait for all workers to finish.
+	var wg sync.WaitGroup
+
+	// Channel to receive errors from each iteration job.
+	errCh := make(chan error, workers)
+	// Channel to cancel all iteration jobs.
+	cancelCh := make(chan struct{})
+
+	worker := func(start, end common.Hash) {
+		// Decrement the WaitGroup when the function returns.
+		defer wg.Done()
+
+		db, err := dbFactory()
+		if err != nil {
+			// Should never happen, so explode if it does.
+			log.Crit("cannot create state db", "err", err)
+		}
+		st, err := db.StorageTrie(address)
+		if err != nil {
+			// Should never happen, so explode if it does.
+			log.Crit("cannot get storage trie", "address", address, "err", err)
+		}
+		// st can be nil if the account doesn't exist.
+		if st == nil {
+			errCh <- fmt.Errorf("account does not exist: %s", address.Hex())
+			return
+		}
+
+		it := trie.NewIterator(st.NodeIterator(start.Bytes()))
+
+		// Below code is largely based on db.ForEachStorage. We can't use that
+		// because it doesn't allow us to specify a start and end key.
+		for it.Next() {
+			select {
+			case <-cancelCh:
+				// If one of the workers encounters an error, cancel all of them.
+				return
+			default:
+				break
+			}
+
+			// Use the raw (i.e., secure hashed) key to check if we've reached
+			// the end of the partition. Use > rather than >= here to account for
+			// the fact that the values returned by PartitionKeys are inclusive.
+			// Duplicate addresses that may be returned by this iteration are
+			// filtered out in the collector.
+			if new(big.Int).SetBytes(it.Key).Cmp(end.Big()) > 0 {
+				return
+			}
+
+			// Skip if the value is empty.
+			rawValue := it.Value
+			if len(rawValue) == 0 {
+				continue
+			}
+
+			// Get the preimage.
+			rawKey := st.GetKey(it.Key)
+			if rawKey == nil {
+				// Should never happen, so explode if it does.
+				log.Crit("cannot get preimage for storage key", "key", it.Key)
+			}
+			key := common.BytesToHash(rawKey)
+
+			// Parse the raw value.
+			_, content, _, err := rlp.Split(rawValue)
+			if err != nil {
+				// Should never happen, so explode if it does.
+				log.Crit("mal-formed data in state: %v", err)
+			}
+
+			value := common.BytesToHash(content)
+
+			// Call the callback with the DB, key, and value. Errors get
+			// bubbled up to the errCh.
+			if err := cb(db, key, value); err != nil {
+				errCh <- err
+				return
+			}
+		}
+	}
+
+	for i := 0; i < workers; i++ {
+		wg.Add(1)
+
+		// Partition the keyspace per worker.
+		start, end := PartitionKeyspace(i, workers)
+
+		// Kick off our worker.
+		go worker(start, end)
+	}
+
+	wg.Wait()
+
+	for len(errCh) > 0 {
+		err := <-errCh
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// PartitionKeyspace divides the key space into partitions by dividing the maximum keyspace
+// by count then multiplying by i. This will leave some slots left over, which we handle below. It
+// returns the start and end keys for the partition as a common.Hash. Note that the returned range
+// of keys is inclusive, i.e., [start, end] NOT [start, end).
+func PartitionKeyspace(i int, count int) (common.Hash, common.Hash) {
+	if i < 0 || count < 0 {
+		panic("i and count must be greater than 0")
+	}
+
+	if i > count-1 {
+		panic("i must be less than count - 1")
+	}
+
+	// Divide the key space into partitions by dividing the key space by the number
+	// of jobs. This will leave some slots left over, which we handle below.
+	partSize := new(big.Int).Div(maxSlot.Big(), big.NewInt(int64(count)))
+
+	start := common.BigToHash(new(big.Int).Mul(big.NewInt(int64(i)), partSize))
+	var end common.Hash
+	if i < count-1 {
+		// If this is not the last partition, use the next partition's start key as the end.
+		end = common.BigToHash(new(big.Int).Mul(big.NewInt(int64(i+1)), partSize))
+	} else {
+		// If this is the last partition, use the max slot as the end.
+		end = maxSlot
+	}
+
+	return start, end
+}

op-chain-ops/util/state_iterator_test.go

+package util
+
+import (
+	crand "crypto/rand"
+	"fmt"
+	"math/rand"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/trie"
+	"github.com/stretchr/testify/require"
+)
+
+var testAddr = common.Address{0: 0xff}
+
+func TestStateIteratorWorkers(t *testing.T) {
+	_, factory, _ := setupRandTest(t)
+
+	for i := -1; i <= 0; i++ {
+		require.Panics(t, func() {
+			_ = IterateState(factory, testAddr, func(db *state.StateDB, key, value common.Hash) error {
+				return nil
+			}, i)
+		})
+	}
+}
+
+func TestStateIteratorNonexistentAccount(t *testing.T) {
+	_, factory, _ := setupRandTest(t)
+
+	require.ErrorContains(t, IterateState(factory, common.Address{}, func(db *state.StateDB, key, value common.Hash) error {
+		return nil
+	}, 1), "account does not exist")
+}
+
+func TestStateIteratorRandomOK(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		hashes, factory, workerCount := setupRandTest(t)
+
+		seenHashes := make(map[common.Hash]bool)
+		hashCh := make(chan common.Hash)
+		doneCh := make(chan struct{})
+		go func() {
+			defer close(doneCh)
+			for hash := range hashCh {
+				seenHashes[hash] = true
+			}
+		}()
+
+		require.NoError(t, IterateState(factory, testAddr, func(db *state.StateDB, key, value common.Hash) error {
+			hashCh <- key
+			return nil
+		}, workerCount))
+
+		close(hashCh)
+		<-doneCh
+
+		// Perform a less or equal check here in case of duplicates. The map check below will assert
+		// that all of the hashes are accounted for.
+		require.LessOrEqual(t, len(seenHashes), len(hashes))
+
+		// Every hash we put into state should have been iterated over.
+		for _, hash := range hashes {
+			require.Contains(t, seenHashes, hash)
+		}
+	}
+}
+
+func TestStateIteratorRandomError(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		hashes, factory, workerCount := setupRandTest(t)
+
+		failHash := hashes[rand.Intn(len(hashes))]
+		require.ErrorContains(t, IterateState(factory, testAddr, func(db *state.StateDB, key, value common.Hash) error {
+			if key == failHash {
+				return fmt.Errorf("test error")
+			}
+			return nil
+		}, workerCount), "test error")
+	}
+}
+
+func TestPartitionKeyspace(t *testing.T) {
+	tests := []struct {
+		i        int
+		count    int
+		expected [2]common.Hash
+	}{
+		{
+			i:     0,
+			count: 1,
+			expected: [2]common.Hash{
+				common.HexToHash("0x00"),
+				common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+			},
+		},
+		{
+			i:     0,
+			count: 2,
+			expected: [2]common.Hash{
+				common.HexToHash("0x00"),
+				common.HexToHash("0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+			},
+		},
+		{
+			i:     1,
+			count: 2,
+			expected: [2]common.Hash{
+				common.HexToHash("0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+				common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+			},
+		},
+		{
+			i:     0,
+			count: 3,
+			expected: [2]common.Hash{
+				common.HexToHash("0x00"),
+				common.HexToHash("0x5555555555555555555555555555555555555555555555555555555555555555"),
+			},
+		},
+		{
+			i:     1,
+			count: 3,
+			expected: [2]common.Hash{
+				common.HexToHash("0x5555555555555555555555555555555555555555555555555555555555555555"),
+				common.HexToHash("0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+			},
+		},
+		{
+			i:     2,
+			count: 3,
+			expected: [2]common.Hash{
+				common.HexToHash("0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+				common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"),
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(fmt.Sprintf("i %d, count %d", tt.i, tt.count), func(t *testing.T) {
+			start, end := PartitionKeyspace(tt.i, tt.count)
+			require.Equal(t, tt.expected[0], start)
+			require.Equal(t, tt.expected[1], end)
+		})
+	}
+
+	t.Run("panics on invalid i or count", func(t *testing.T) {
+		require.Panics(t, func() {
+			PartitionKeyspace(1, 1)
+		})
+		require.Panics(t, func() {
+			PartitionKeyspace(-1, 1)
+		})
+		require.Panics(t, func() {
+			PartitionKeyspace(0, -1)
+		})
+		require.Panics(t, func() {
+			PartitionKeyspace(-1, -1)
+		})
+	})
+}
+
+func setupRandTest(t *testing.T) ([]common.Hash, DBFactory, int) {
+	memDB := rawdb.NewMemoryDatabase()
+	db, err := state.New(common.Hash{}, state.NewDatabaseWithConfig(memDB, &trie.Config{
+		Preimages: true,
+		Cache:     1024,
+	}), nil)
+	require.NoError(t, err)
+
+	hashCount := rand.Intn(100)
+	if hashCount == 0 {
+		hashCount = 1
+	}
+
+	hashes := make([]common.Hash, hashCount)
+
+	db.CreateAccount(testAddr)
+
+	for j := 0; j < hashCount; j++ {
+		hashes[j] = randHash(t)
+		db.SetState(testAddr, hashes[j], hashes[j])
+	}
+
+	root, err := db.Commit(false)
+	require.NoError(t, err)
+
+	err = db.Database().TrieDB().Commit(root, true)
+	require.NoError(t, err)
+
+	factory := func() (*state.StateDB, error) {
+		return state.New(root, state.NewDatabaseWithConfig(memDB, &trie.Config{
+			Preimages: true,
+			Cache:     1024,
+		}), nil)
+	}
+
+	workerCount := rand.Intn(64)
+	if workerCount == 0 {
+		workerCount = 1
+	}
+	return hashes, factory, workerCount
+}
+
+func randHash(t *testing.T) common.Hash {
+	var h common.Hash
+	_, err := crand.Read(h[:])
+	require.NoError(t, err)
+	return h
+}

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"
@@ -51,6 +52,7 @@ func NewL2Proposer(t Testing, log log.Logger, cfg *ProposerCfg, l1 *ethclient.Cl
 			NumConfirmations:          1,
 			SafeAbortNonceTooLowCount: 4,
 			From:                      from,
+			ChainID:                   big.NewInt(420),
 			// Signer is loaded in `proposer.NewL2OutputSubmitter`
 		},
 		L1Client:          l1,
@@ -60,7 +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,
@@ -327,6 +329,8 @@ func TestMigration(t *testing.T) {
 		L1EthRpc:                  forkedL1URL,
 		L2EthRpc:                  gethNode.WSEndpoint(),
 		RollupRpc:                 rollupNode.HTTPEndpoint(),
+		TxManagerTimeout:          10 * time.Minute,
+		OfflineGasEstimation:      true,
 		MaxChannelDuration:        1,
 		MaxL1TxSize:               120_000,
 		TargetL1TxSize:            100_000,
@@ -362,7 +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)
 	}
@@ -582,10 +590,13 @@ func (cfg SystemConfig) Start(_opts ...SystemConfigOption) (*System, error) {
 	}
 
 	// Batch Submitter
+	txManagerTimeout := 10 * time.Minute
 	sys.BatchSubmitter, err = bss.NewBatchSubmitterFromCLIConfig(bss.CLIConfig{
 		L1EthRpc:                  sys.Nodes["l1"].WSEndpoint(),
 		L2EthRpc:                  sys.Nodes["sequencer"].WSEndpoint(),
 		RollupRpc:                 sys.RollupNodes["sequencer"].HTTPEndpoint(),
+		TxManagerTimeout:          txManagerTimeout,
+		OfflineGasEstimation:      true,
 		MaxChannelDuration:        1,
 		MaxL1TxSize:               120_000,
 		TargetL1TxSize:            100_000,
@@ -606,9 +617,12 @@ func (cfg SystemConfig) Start(_opts ...SystemConfigOption) (*System, error) {
 		return nil, fmt.Errorf("failed to setup 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/cmd/batch_decoder/README.md

@@ -52,6 +52,12 @@ jq "select(.valid_data == false)|.tx.hash" $TX_DIR
 
 # Select all channels that are not ready and then get the id and inclusion block & tx hash of the first frame.
 jq "select(.is_ready == false)|[.id, .frames[0].inclusion_block, .frames[0].transaction_hash]"  $CHANNEL_DIR
+
+# Show all of the frames in a channel without seeing the batches or frame data
+jq 'del(.batches)|del(.frames[]|.frame.data)' $CHANNEL_FILE
+
+# Show all batches (without timestamps) in a channel
+jq '.batches|del(.[]|.Transactions)' $CHANNEL_FILE
 ```
 
 

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

@@ -14,10 +14,10 @@ import (
 
 // Flags
 
-const envVarPrefix = "OP_NODE_"
+const envVarPrefix = "OP_NODE"
 
 func prefixEnvVar(name string) string {
-	return envVarPrefix + name
+	return envVarPrefix + "_" + name
 }
 
 var (
@@ -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)
+	n.l2Driver = driver.NewDriver(&cfg.Driver, &cfg.Rollup, n.l2Source, n.l1Source, n, n, n.log, snapshotLog, n.metrics)
+
+	return nil
+}
+
+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
+	}
 
-			// The sync client's RPC is always trusted
-			config := sources.SyncClientDefaultConfig(&cfg.Rollup, true)
+	config := sources.SyncClientDefaultConfig(&cfg.Rollup, trustRPC)
 
-			syncClient, err = sources.NewSyncClient(n.OnUnsafeL2Payload, rpcSyncClient, n.log, n.metrics.L2SourceCache, config)
+	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.l2Driver = driver.NewDriver(&cfg.Driver, &cfg.Rollup, n.l2Source, n.l1Source, syncClient, n, n.log, snapshotLog, n.metrics)
-
+	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"
@@ -11,6 +16,68 @@ type scorer struct {
 	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,
+		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/channel_out.go

@@ -14,9 +14,17 @@ import (
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
+var ErrMaxFrameSizeTooSmall = errors.New("maxSize is too small to fit the fixed frame overhead")
 var ErrNotDepositTx = errors.New("first transaction in block is not a deposit tx")
 var ErrTooManyRLPBytes = errors.New("batch would cause RLP bytes to go over limit")
 
+// FrameV0OverHeadSize is the absolute minimum size of a frame.
+// This is the fixed overhead frame size, calculated as specified
+// in the [Frame Format] specs: 16 + 2 + 4 + 1 = 23 bytes.
+//
+// [Frame Format]: https://github.com/ethereum-optimism/optimism/blob/develop/specs/derivation.md#frame-format
+const FrameV0OverHeadSize = 23
+
 type ChannelOut struct {
 	id ChannelID
 	// Frame ID of the next frame to emit. Increment after emitting
@@ -141,19 +149,23 @@ func (co *ChannelOut) Close() error {
 // OutputFrame writes a frame to w with a given max size and returns the frame
 // number.
 // Use `ReadyBytes`, `Flush`, and `Close` to modify the ready buffer.
-// Returns io.EOF when the channel is closed & there are no more frames
+// Returns an error if the `maxSize` < FrameV0OverHeadSize.
+// Returns io.EOF when the channel is closed & there are no more frames.
 // Returns nil if there is still more buffered data.
-// Returns and error if it ran into an error during processing.
+// Returns an error if it ran into an error during processing.
 func (co *ChannelOut) OutputFrame(w *bytes.Buffer, maxSize uint64) (uint16, error) {
 	f := Frame{
 		ID:          co.id,
 		FrameNumber: uint16(co.frame),
 	}
 
+	// Check that the maxSize is large enough for the frame overhead size.
+	if maxSize < FrameV0OverHeadSize {
+		return 0, ErrMaxFrameSizeTooSmall
+	}
+
 	// Copy data from the local buffer into the frame data buffer
-	// Don't go past the maxSize with the fixed frame overhead.
-	// Fixed overhead: 16 + 2 + 4 + 1 = 23 bytes.
-	maxDataSize := maxSize - 23
+	maxDataSize := maxSize - FrameV0OverHeadSize
 	if maxDataSize > uint64(co.buf.Len()) {
 		maxDataSize = uint64(co.buf.Len())
 		// If we are closed & will not spill past the current frame

op-node/rollup/derive/channel_out_test.go

@@ -29,6 +29,22 @@ func TestChannelOutAddBlock(t *testing.T) {
 	})
 }
 
+// TestOutputFrameSmallMaxSize tests that calling [OutputFrame] with a small
+// max size that is below the fixed frame size overhead of 23, will return
+// an error.
+func TestOutputFrameSmallMaxSize(t *testing.T) {
+	cout, err := NewChannelOut()
+	require.NoError(t, err)
+
+	// Call OutputFrame with the range of small max size values that err
+	var w bytes.Buffer
+	for i := 0; i < 23; i++ {
+		fid, err := cout.OutputFrame(&w, uint64(i))
+		require.ErrorIs(t, err, ErrMaxFrameSizeTooSmall)
+		require.Zero(t, fid)
+	}
+}
+
 // TestRLPByteLimit ensures that stream encoder is properly limiting the length.
 // It will decode the input if `len(input) <= inputLimit`.
 func TestRLPByteLimit(t *testing.T) {

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
@@ -132,11 +132,7 @@ func NewEngineQueue(log log.Logger, cfg *rollup.Config, engine Engine, metrics M
 		engine:         engine,
 		metrics:        metrics,
 		finalityData:   make([]FinalityData, 0, finalityLookback),
-		unsafePayloads: PayloadsQueue{
-			MaxSize:  maxUnsafePayloadsMemory,
-			SizeFn:   payloadMemSize,
-			blockNos: make(map[uint64]bool),
-		},
+		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_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)
+}