feat: ignore KromaMPT block payload

Prevents KromaMPT block from being handled as unsafe payload over P2P.
This ensures that nodes can continue the migration process, even if they
receive a new unsafe payload from the sequencer before receiving the batch
containing the KromaMPT parent block, allowing them to still process the
safe attribute.

op-batcher/batcher/channel_builder.go

@@ -21,7 +21,8 @@ var (
 	ErrSeqWindowClose        = errors.New("close to sequencer window timeout")
 	ErrTerminated            = errors.New("channel terminated")
 	// [Kroma: START]
-	ErrJustBeforeKromaMPTTime = errors.New("reached the block just before KromaMPTTime")
+	ErrReachedKromaMPTParentBlock = errors.New("reached the parent block of KromaMPT")
+	ErrReachedKromaMPTBlock       = errors.New("reached the KromaMPT block")
 	// [Kroma: END]
 )
 
@@ -177,8 +178,15 @@ func (c *ChannelBuilder) AddBlock(block *types.Block) (*derive.L1BlockInfo, erro
 	if err = c.co.FullErr(); err != nil {
 		c.setFullErr(err)
 		// Adding this block still worked, so don't return error, just mark as full
-	} else /* [Kroma: START] */ if c.rollupCfg.KromaMPTTime != nil && block.Time() == *c.rollupCfg.KromaMPTTime-c.rollupCfg.BlockTime {
-		c.setFullErr(ErrJustBeforeKromaMPTTime)
+	}
+
+	// [Kroma: START]
+	if c.rollupCfg.KromaMPTTime != nil {
+		if c.rollupCfg.IsKromaMPTParentBlock(block.Time() - c.rollupCfg.BlockTime) {
+			c.setFullErr(ErrReachedKromaMPTParentBlock)
+		} else if c.rollupCfg.IsKromaMPTActivationBlock(block.Time()) {
+			c.setFullErr(ErrReachedKromaMPTBlock)
+		}
 	}
 	// [Kroma: END]
 

op-batcher/batcher/channel_manager_test.go

@@ -7,16 +7,17 @@ import (
 	"testing"
 	"time"
 
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/stretchr/testify/require"
+
 	"github.com/ethereum-optimism/optimism/op-batcher/metrics"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
 	derivetest "github.com/ethereum-optimism/optimism/op-node/rollup/derive/test"
 	"github.com/ethereum-optimism/optimism/op-service/eth"
 	"github.com/ethereum-optimism/optimism/op-service/testlog"
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/log"
-	"github.com/stretchr/testify/require"
 )
 
 func channelManagerTestConfig(maxFrameSize uint64, batchType uint) ChannelConfig {
@@ -529,7 +530,7 @@ func TestChannelManager_Close_BeforeMPTBlock(t *testing.T) {
 	txdata, err := m.TxData(eth.BlockID{})
 	require.NoError(err)
 	ch1 := m.txChannels[txdata.ID().String()]
-	require.ErrorIs(ch1.FullErr(), ErrJustBeforeKromaMPTTime)
+	require.ErrorIs(ch1.FullErr(), ErrReachedKromaMPTParentBlock)
 
 	// current channel is not full yet
 	_, err = m.TxData(eth.BlockID{})

op-node/node/node.go

@@ -594,6 +594,13 @@ func (n *OpNode) OnUnsafeL2Payload(ctx context.Context, from peer.ID, envelope *
 		return nil
 	}
 
+	// [Kroma: START]
+	if n.runCfg.rollupCfg.IsKromaMPTActivationBlock(uint64(envelope.ExecutionPayload.Timestamp)) {
+		n.log.Info("Received the payload of the KromaMPT block from p2p but ignored it", "id", envelope.ExecutionPayload.ID(), "peer", from)
+		return nil
+	}
+	// [Kroma: END]
+
 	n.tracer.OnUnsafeL2Payload(ctx, from, envelope)
 
 	n.log.Info("Received signed execution payload from p2p", "id", envelope.ExecutionPayload.ID(), "peer", from)

op-node/rollup/types.go

@@ -371,6 +371,14 @@ func (c *Config) IsKromaMPT(timestamp uint64) bool {
 	return c.KromaMPTTime != nil && timestamp >= *c.KromaMPTTime
 }
 
+// IsKromaMPTActivationBlock returns whether the specified block is the first block subject to the
+// KromaMPT upgrade. KromaMPT activation at genesis does not count.
+func (c *Config) IsKromaMPTActivationBlock(l2BlockTime uint64) bool {
+	return c.IsKromaMPT(l2BlockTime) &&
+		l2BlockTime >= c.BlockTime &&
+		!c.IsKromaMPT(l2BlockTime-c.BlockTime)
+}
+
 // IsKromaMPTParentBlock returns whether the specified block is the parent block subject to the
 // KromaMPT upgrade. KromaMPT activation at genesis does not count.
 func (c *Config) IsKromaMPTParentBlock(l2BlockTime uint64) bool {