draft: ban-deposits-interop first RFC draft

op-node/rollup/derive/attributes.go

@@ -121,9 +121,19 @@ func (ba *FetchingAttributesBuilder) PreparePayloadAttributes(ctx context.Contex
 		return nil, NewCriticalError(fmt.Errorf("failed to create l1InfoTx: %w", err))
 	}
 
-	txs := make([]hexutil.Bytes, 0, 1+len(depositTxs)+len(upgradeTxs))
+	var postDeposits []hexutil.Bytes
+	if ba.rollupCfg.IsInterop(nextL2Time) {
+		depositsCompleteTx, err := DepositsCompleteBytes(ba.rollupCfg, sysConfig, seqNumber, l1Info, nextL2Time)
+		if err != nil {
+			return nil, NewCriticalError(fmt.Errorf("failed to create depositsCompleteTx: %w", err))
+		}
+		postDeposits = append(postDeposits, depositsCompleteTx)
+	}
+
+	txs := make([]hexutil.Bytes, 0, 1+len(depositTxs)+len(postDeposits)+len(upgradeTxs))
 	txs = append(txs, l1InfoTx)
 	txs = append(txs, depositTxs...)
+	txs = append(txs, postDeposits...)
 	txs = append(txs, upgradeTxs...)
 
 	var withdrawals *types.Withdrawals

op-node/rollup/derive/l1_block_info.go

@@ -20,14 +20,17 @@ import (
 const (
 	L1InfoFuncBedrockSignature = "setL1BlockValues(uint64,uint64,uint256,bytes32,uint64,bytes32,uint256,uint256)"
 	L1InfoFuncEcotoneSignature = "setL1BlockValuesEcotone()"
+	DepositsCompleteSignature  = "depositsComplete()"
 	L1InfoArguments            = 8
 	L1InfoBedrockLen           = 4 + 32*L1InfoArguments
 	L1InfoEcotoneLen           = 4 + 32*5 // after Ecotone upgrade, args are packed into 5 32-byte slots
+	DepositsCompleteLen        = 4        // only the selector
 )
 
 var (
 	L1InfoFuncBedrockBytes4 = crypto.Keccak256([]byte(L1InfoFuncBedrockSignature))[:4]
 	L1InfoFuncEcotoneBytes4 = crypto.Keccak256([]byte(L1InfoFuncEcotoneSignature))[:4]
+	DepositsCompleteBytes4  = crypto.Keccak256([]byte(DepositsCompleteSignature))[:4]
 	L1InfoDepositerAddress  = common.HexToAddress("0xdeaddeaddeaddeaddeaddeaddeaddeaddead0001")
 	L1BlockAddress          = predeploys.L1BlockAddr
 	ErrInvalidFormat        = errors.New("invalid ecotone l1 block info format")
@@ -259,6 +262,34 @@ func L1BlockInfoFromBytes(rollupCfg *rollup.Config, l2BlockTime uint64, data []b
 	return &info, info.unmarshalBinaryBedrock(data)
 }
 
+func (info *L1BlockInfo) marshalDepositsComplete() ([]byte, error) {
+	w := bytes.NewBuffer(make([]byte, 0, DepositsCompleteLen))
+	if err := solabi.WriteSignature(w, []byte(DepositsCompleteBytes4)); err != nil {
+		return nil, err
+	}
+	return w.Bytes(), nil
+}
+
+func (info *L1BlockInfo) unmarshalDepositsComplete(data []byte) error {
+	if len(data) != DepositsCompleteLen {
+		return fmt.Errorf("data is unexpected length: %d", len(data))
+	}
+	r := bytes.NewReader(data)
+
+	if _, err := solabi.ReadAndValidateSignature(r, DepositsCompleteBytes4); err != nil {
+		return err
+	}
+	if !solabi.EmptyReader(r) {
+		return errors.New("too many bytes")
+	}
+	return nil
+}
+
+func DepositCompletedFromBytes(rollupCfg *rollup.Config, l2BlockTime uint64, data []byte) (*L1BlockInfo, error) {
+	var info L1BlockInfo
+	return &info, info.unmarshalDepositsComplete(data)
+}
+
 // L1InfoDeposit creates a L1 Info deposit transaction based on the L1 block,
 // and the L2 block-height difference with the start of the epoch.
 func L1InfoDeposit(rollupCfg *rollup.Config, sysCfg eth.SystemConfig, seqNumber uint64, block eth.BlockInfo, l2BlockTime uint64) (*types.DepositTx, error) {
@@ -335,3 +366,53 @@ func L1InfoDepositBytes(rollupCfg *rollup.Config, sysCfg eth.SystemConfig, seqNu
 	}
 	return opaqueL1Tx, nil
 }
+
+func DepositsCompleteDeposit(rollupCfg *rollup.Config, sysCfg eth.SystemConfig, seqNumber uint64, block eth.BlockInfo, l2BlockTime uint64) (*types.DepositTx, error) {
+	l1BlockInfo := L1BlockInfo{
+		Number:         block.NumberU64(),
+		Time:           block.Time(),
+		BaseFee:        block.BaseFee(),
+		BlockHash:      block.Hash(),
+		SequenceNumber: seqNumber,
+		BatcherAddr:    sysCfg.BatcherAddr,
+	}
+	data, err := l1BlockInfo.marshalDepositsComplete()
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal Bedrock l1 block info: %w", err)
+	}
+	source := L1InfoDepositSource{
+		L1BlockHash: block.Hash(),
+		SeqNumber:   seqNumber,
+	}
+	// Set a normal gas limit with `IsSystemTransaction` to ensure
+	// that the DepositCompleted Transaction does not run out of gas.
+	out := &types.DepositTx{
+		SourceHash:          source.SourceHash(),
+		From:                L1InfoDepositerAddress,
+		To:                  &L1BlockAddress,
+		Mint:                nil,
+		Value:               big.NewInt(0),
+		Gas:                 50_000,
+		IsSystemTransaction: false,
+		Data:                data,
+	}
+	// With the regolith fork we disable the IsSystemTx functionality, and allocate real gas
+	if rollupCfg.IsRegolith(l2BlockTime) {
+		out.IsSystemTransaction = false
+		out.Gas = RegolithSystemTxGas
+	}
+	return out, nil
+}
+
+func DepositsCompleteBytes(rollupCfg *rollup.Config, sysCfg eth.SystemConfig, seqNumber uint64, l1Info eth.BlockInfo, l2BlockTime uint64) ([]byte, error) {
+	dep, err := DepositsCompleteDeposit(rollupCfg, sysCfg, seqNumber, l1Info, l2BlockTime)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create DepositsComplete tx: %w", err)
+	}
+	depositsCompleteTx := types.NewTx(dep)
+	opaqueDepositsCompleteTx, err := depositsCompleteTx.MarshalBinary()
+	if err != nil {
+		return nil, fmt.Errorf("failed to encode DepositsComplete tx: %w", err)
+	}
+	return opaqueDepositsCompleteTx, nil
+}

op-node/rollup/types.go

@@ -489,6 +489,7 @@ func (c *Config) IsHoloceneActivationBlock(l2BlockTime uint64) bool {
 		!c.IsHolocene(l2BlockTime-c.BlockTime)
 }
 
+// TODO rename to IsIsthmusActivationBlock (this will require quite a bit of renaming)
 func (c *Config) IsInteropActivationBlock(l2BlockTime uint64) bool {
 	return c.IsInterop(l2BlockTime) &&
 		l2BlockTime >= c.BlockTime &&

packages/contracts-bedrock/src/L2/CrossL2Inbox.sol

@@ -29,6 +29,9 @@ error InvalidChainId();
 /// @notice Thrown when trying to execute a cross chain message and the target call fails.
 error TargetCallFailed();
 
+/// @notice Thrown when trying to execute a cross chain message on a deposit transaction.
+error NoExecutingDeposits();
+
 /// @custom:proxied
 /// @custom:predeploy 0x4200000000000000000000000000000000000022
 /// @title CrossL2Inbox
@@ -114,6 +117,9 @@ contract CrossL2Inbox is ICrossL2Inbox, ISemver, TransientReentrancyAware {
         payable
         reentrantAware
     {
+        // We need to know if this is being called on a depositTx
+        if (L1_BLOCK.isDeposit()) revert NoExecutingDeposits();
+
         if (_id.timestamp > block.timestamp) revert InvalidTimestamp();
         if (!IDependencySet(Predeploys.L1_BLOCK_ATTRIBUTES).isInDependencySet(_id.chainId)) {
             revert InvalidChainId();

packages/contracts-bedrock/src/L2/L1Block.sol

@@ -57,6 +57,9 @@ contract L1Block is ISemver, IGasToken {
     /// @notice The latest L1 blob base fee.
     uint256 public blobBaseFee;
 
+    /// @notice The isDeposit flag.
+    bool public isDeposit;
+
     /// @custom:semver 1.4.1-beta.1
     function version() public pure virtual returns (string memory) {
         return "1.4.1-beta.1";
@@ -87,6 +90,11 @@ contract L1Block is ISemver, IGasToken {
         return token != Constants.ETHER;
     }
 
+    function isDeposit() returns (bool _isDeposit) external view {
+        require(msg.sender == CROSS_L2_INBOX, "L1Block: only the CrossL2Inbox can check if it is a deposit");
+        _isDeposit = isDeposit;
+    }
+
     /// @custom:legacy
     /// @notice Updates the L1 block values.
     /// @param _number         L1 blocknumber.
@@ -97,6 +105,7 @@ contract L1Block is ISemver, IGasToken {
     /// @param _batcherHash    Versioned hash to authenticate batcher by.
     /// @param _l1FeeOverhead  L1 fee overhead.
     /// @param _l1FeeScalar    L1 fee scalar.
+    /// @param _isDeposit      isDeposit flag
     function setL1BlockValues(
         uint64 _number,
         uint64 _timestamp,
@@ -105,7 +114,8 @@ contract L1Block is ISemver, IGasToken {
         uint64 _sequenceNumber,
         bytes32 _batcherHash,
         uint256 _l1FeeOverhead,
-        uint256 _l1FeeScalar
+        uint256 _l1FeeScalar,
+        bool _isDeposit
     )
         external
     {
@@ -119,6 +129,14 @@ contract L1Block is ISemver, IGasToken {
         batcherHash = _batcherHash;
         l1FeeOverhead = _l1FeeOverhead;
         l1FeeScalar = _l1FeeScalar;
+        isDeposit = _isDeposit;
+    }
+
+    // TODO natspec
+    function setL1BlockValuesIsthmus() external {
+        isDeposit = true;
+        setL1BlockValuesEcotone(calldata);
+        // TODO ^ this is an example... we might need to do an assembly low-level call here
     }
 
     /// @notice Updates the L1 block values for an Ecotone upgraded chain.
@@ -162,4 +180,10 @@ contract L1Block is ISemver, IGasToken {
 
         emit GasPayingTokenSet({ token: _token, decimals: _decimals, name: _name, symbol: _symbol });
     }
+
+    /// @notice Resets the isDeposit flag.
+    function depositsComplete() external {
+        if (msg.sender != DEPOSITOR_ACCOUNT()) revert NotDepositor();
+        isDeposit = false;
+    }
 }