Merge pull request #2113 from ethereum-optimism/sc/sdk-finalize-message

feat(sdk): implement finalize message

packages/sdk/package.json

@@ -63,6 +63,8 @@
     "@eth-optimism/core-utils": "0.7.5",
     "@ethersproject/abstract-provider": "^5.5.1",
     "@ethersproject/abstract-signer": "^5.5.0",
-    "ethers": "^5.5.2"
+    "ethers": "^5.5.2",
+    "merkletreejs": "^0.2.27",
+    "rlp": "^2.2.7"
   }
 }

packages/sdk/src/adapters/standard-bridge.ts

@@ -245,7 +245,7 @@ export class StandardBridgeAdapter implements IBridgeAdapter {
         throw new Error(`token pair not supported by bridge`)
       }
 
-      return this.l1Bridge.depositERC20(
+      return this.l1Bridge.populateTransaction.depositERC20(
         toAddress(l1Token),
         toAddress(l2Token),
         amount,

packages/sdk/src/cross-chain-messenger.ts

-/* eslint-disable @typescript-eslint/no-unused-vars */
 import { ethers, Overrides, Signer, BigNumber } from 'ethers'
 import {
   TransactionRequest,
@@ -10,7 +9,6 @@ import {
   CrossChainMessageRequest,
   ICrossChainMessenger,
   ICrossChainProvider,
-  IBridgeAdapter,
   MessageLike,
   NumberLike,
   AddressLike,
@@ -77,7 +75,9 @@ export class CrossChainMessenger implements ICrossChainMessenger {
       overrides?: Overrides
     }
   ): Promise<TransactionResponse> {
-    throw new Error('Not implemented')
+    return this.l1Signer.sendTransaction(
+      await this.populateTransaction.finalizeMessage(message, opts)
+    )
   }
 
   public async depositETH(
@@ -149,9 +149,7 @@ export class CrossChainMessenger implements ICrossChainMessenger {
       }
     ): Promise<TransactionRequest> => {
       if (message.direction === MessageDirection.L1_TO_L2) {
-        return this.provider.contracts.l1.L1CrossDomainMessenger.connect(
-          this.l1Signer
-        ).populateTransaction.sendMessage(
+        return this.provider.contracts.l1.L1CrossDomainMessenger.populateTransaction.sendMessage(
           message.target,
           message.message,
           opts?.l2GasLimit ||
@@ -159,9 +157,7 @@ export class CrossChainMessenger implements ICrossChainMessenger {
           opts?.overrides || {}
         )
       } else {
-        return this.provider.contracts.l2.L2CrossDomainMessenger.connect(
-          this.l2Signer
-        ).populateTransaction.sendMessage(
+        return this.provider.contracts.l2.L2CrossDomainMessenger.populateTransaction.sendMessage(
           message.target,
           message.message,
           0, // Gas limit goes unused when sending from L2 to L1
@@ -182,9 +178,7 @@ export class CrossChainMessenger implements ICrossChainMessenger {
         throw new Error(`cannot resend L2 to L1 message`)
       }
 
-      return this.provider.contracts.l1.L1CrossDomainMessenger.connect(
-        this.l1Signer
-      ).populateTransaction.replayMessage(
+      return this.provider.contracts.l1.L1CrossDomainMessenger.populateTransaction.replayMessage(
         resolved.target,
         resolved.sender,
         resolved.message,
@@ -201,7 +195,20 @@ export class CrossChainMessenger implements ICrossChainMessenger {
         overrides?: Overrides
       }
     ): Promise<TransactionRequest> => {
-      throw new Error('Not implemented')
+      const resolved = await this.provider.toCrossChainMessage(message)
+      if (resolved.direction === MessageDirection.L1_TO_L2) {
+        throw new Error(`cannot finalize L1 to L2 message`)
+      }
+
+      const proof = await this.provider.getMessageProof(resolved)
+      return this.provider.contracts.l1.L1CrossDomainMessenger.populateTransaction.relayMessage(
+        resolved.target,
+        resolved.sender,
+        resolved.message,
+        resolved.messageNonce,
+        proof,
+        opts?.overrides || {}
+      )
     },
 
     depositETH: async (
@@ -297,7 +304,9 @@ export class CrossChainMessenger implements ICrossChainMessenger {
         overrides?: Overrides
       }
     ): Promise<BigNumber> => {
-      throw new Error('Not implemented')
+      return this.provider.l1Provider.estimateGas(
+        await this.populateTransaction.finalizeMessage(message, opts)
+      )
     },
 
     depositETH: async (
@@ -332,7 +341,7 @@ export class CrossChainMessenger implements ICrossChainMessenger {
         overrides?: Overrides
       }
     ): Promise<BigNumber> => {
-      return this.provider.l2Provider.estimateGas(
+      return this.provider.l1Provider.estimateGas(
         await this.populateTransaction.depositERC20(
           l1Token,
           l2Token,

packages/sdk/src/cross-chain-provider.ts

@@ -5,7 +5,7 @@ import {
   TransactionReceipt,
 } from '@ethersproject/abstract-provider'
 import { ethers, BigNumber } from 'ethers'
-import { sleep } from '@eth-optimism/core-utils'
+import { sleep, remove0x } from '@eth-optimism/core-utils'
 
 import {
   ICrossChainProvider,
@@ -19,6 +19,7 @@ import {
   ProviderLike,
   CrossChainMessage,
   CrossChainMessageRequest,
+  CrossChainMessageProof,
   MessageDirection,
   MessageStatus,
   TokenBridgeMessage,
@@ -38,6 +39,9 @@ import {
   getAllOEContracts,
   getBridgeAdapters,
   hashCrossChainMessage,
+  makeMerkleTreeProof,
+  makeStateTrieProof,
+  encodeCrossChainMessage,
 } from './utils'
 
 export class CrossChainProvider implements ICrossChainProvider {
@@ -302,7 +306,7 @@ export class CrossChainProvider implements ICrossChainProvider {
         } else {
           const challengePeriod = await this.getChallengePeriodSeconds()
           const targetBlock = await this.l1Provider.getBlock(
-            stateRoot.blockNumber
+            stateRoot.batch.blockNumber
           )
           const latestBlock = await this.l1Provider.getBlock('latest')
           if (targetBlock.timestamp + challengePeriod > latestBlock.timestamp) {
@@ -492,9 +496,9 @@ export class CrossChainProvider implements ICrossChainProvider {
     }
 
     return {
-      blockNumber: stateRootBatch.blockNumber,
-      header: stateRootBatch.header,
       stateRoot: stateRootBatch.stateRoots[indexInBatch],
+      stateRootIndexInBatch: indexInBatch,
+      batch: stateRootBatch,
     }
   }
 
@@ -599,4 +603,52 @@ export class CrossChainProvider implements ICrossChainProvider {
       },
     }
   }
+
+  public async getMessageProof(
+    message: MessageLike
+  ): Promise<CrossChainMessageProof> {
+    const resolved = await this.toCrossChainMessage(message)
+    if (resolved.direction === MessageDirection.L1_TO_L2) {
+      throw new Error(`can only generate proofs for L2 to L1 messages`)
+    }
+
+    const stateRoot = await this.getMessageStateRoot(resolved)
+    if (stateRoot === null) {
+      throw new Error(`state root for message not yet published`)
+    }
+
+    // We need to calculate the specific storage slot that demonstrates that this message was
+    // actually included in the L2 chain. The following calculation is based on the fact that
+    // messages are stored in the following mapping on L2:
+    // https://github.com/ethereum-optimism/optimism/blob/c84d3450225306abbb39b4e7d6d82424341df2be/packages/contracts/contracts/L2/predeploys/OVM_L2ToL1MessagePasser.sol#L23
+    // You can read more about how Solidity storage slots are computed for mappings here:
+    // https://docs.soliditylang.org/en/v0.8.4/internals/layout_in_storage.html#mappings-and-dynamic-arrays
+    const messageSlot = ethers.utils.keccak256(
+      ethers.utils.keccak256(
+        encodeCrossChainMessage(resolved) +
+          remove0x(this.contracts.l2.L2CrossDomainMessenger.address)
+      ) + '00'.repeat(32)
+    )
+
+    const stateTrieProof = await makeStateTrieProof(
+      this.l2Provider as any,
+      resolved.blockNumber,
+      this.contracts.l2.OVM_L2ToL1MessagePasser.address,
+      messageSlot
+    )
+
+    return {
+      stateRoot: stateRoot.stateRoot,
+      stateRootBatchHeader: stateRoot.batch.header,
+      stateRootProof: {
+        index: stateRoot.stateRootIndexInBatch,
+        siblings: makeMerkleTreeProof(
+          stateRoot.batch.stateRoots,
+          stateRoot.stateRootIndexInBatch
+        ),
+      },
+      stateTrieWitness: stateTrieProof.accountProof,
+      storageTrieWitness: stateTrieProof.storageProof,
+    }
+  }
 }

packages/sdk/src/interfaces/cross-chain-provider.ts

@@ -8,6 +8,7 @@ import {
   AddressLike,
   NumberLike,
   CrossChainMessage,
+  CrossChainMessageProof,
   MessageDirection,
   MessageStatus,
   TokenBridgeMessage,
@@ -287,4 +288,12 @@ export interface ICrossChainProvider {
   getStateRootBatchByTransactionIndex(
     transactionIndex: number
   ): Promise<StateRootBatch | null>
+
+  /**
+   * Generates the proof required to finalize an L2 to L1 message.
+   *
+   * @param message Message to generate a proof for.
+   * @returns Proof that can be used to finalize the message.
+   */
+  getMessageProof(message: MessageLike): Promise<CrossChainMessageProof>
 }

packages/sdk/src/interfaces/types.ts

@@ -216,9 +216,9 @@ export interface StateRootBatchHeader {
  * Information about a state root, including header, block number, and root iself.
  */
 export interface StateRoot {
-  blockNumber: number
-  header: StateRootBatchHeader
   stateRoot: string
+  stateRootIndexInBatch: number
+  batch: StateRootBatch
 }
 
 /**
@@ -230,6 +230,20 @@ export interface StateRootBatch {
   stateRoots: string[]
 }
 
+/**
+ * Proof data required to finalize an L2 to L1 message.
+ */
+export interface CrossChainMessageProof {
+  stateRoot: string
+  stateRootBatchHeader: StateRootBatchHeader
+  stateRootProof: {
+    index: number
+    siblings: string[]
+  }
+  stateTrieWitness: string
+  storageTrieWitness: string
+}
+
 /**
  * Stuff that can be coerced into a transaction.
  */

packages/sdk/src/utils/index.ts

@@ -3,3 +3,4 @@ export * from './contracts'
 export * from './message-encoding'
 export * from './type-utils'
 export * from './misc-utils'
+export * from './merkle-utils'

packages/sdk/src/utils/merkle-utils.ts

+/* Imports: External */
+import { ethers } from 'ethers'
+import {
+  fromHexString,
+  toHexString,
+  toRpcHexString,
+} from '@eth-optimism/core-utils'
+import { MerkleTree } from 'merkletreejs'
+import rlp from 'rlp'
+
+/**
+ * Generates a Merkle proof (using the particular scheme we use within Lib_MerkleTree).
+ *
+ * @param leaves Leaves of the merkle tree.
+ * @param index Index to generate a proof for.
+ * @returns Merkle proof sibling leaves, as hex strings.
+ */
+export const makeMerkleTreeProof = (
+  leaves: string[],
+  index: number
+): string[] => {
+  // Our specific Merkle tree implementation requires that the number of leaves is a power of 2.
+  // If the number of given leaves is less than a power of 2, we need to round up to the next
+  // available power of 2. We fill the remaining space with the hash of bytes32(0).
+  const correctedTreeSize = Math.pow(2, Math.ceil(Math.log2(leaves.length)))
+  const parsedLeaves = []
+  for (let i = 0; i < correctedTreeSize; i++) {
+    if (i < leaves.length) {
+      parsedLeaves.push(leaves[i])
+    } else {
+      parsedLeaves.push(ethers.utils.keccak256('0x' + '00'.repeat(32)))
+    }
+  }
+
+  // merkletreejs prefers things to be Buffers.
+  const bufLeaves = parsedLeaves.map(fromHexString)
+  const tree = new MerkleTree(bufLeaves, (el: Buffer | string): Buffer => {
+    return fromHexString(ethers.utils.keccak256(el))
+  })
+
+  const proof = tree.getProof(bufLeaves[index], index).map((element: any) => {
+    return toHexString(element.data)
+  })
+
+  return proof
+}
+
+/**
+ * Generates a Merkle-Patricia trie proof for a given account and storage slot.
+ *
+ * @param provider RPC provider attached to an EVM-compatible chain.
+ * @param blockNumber Block number to generate the proof at.
+ * @param address Address to generate the proof for.
+ * @param slot Storage slot to generate the proof for.
+ * @returns Account proof and storage proof.
+ */
+export const makeStateTrieProof = async (
+  provider: ethers.providers.JsonRpcProvider,
+  blockNumber: number,
+  address: string,
+  slot: string
+): Promise<{
+  accountProof: string
+  storageProof: string
+}> => {
+  const proof = await provider.send('eth_getProof', [
+    address,
+    [slot],
+    toRpcHexString(blockNumber),
+  ])
+
+  return {
+    accountProof: toHexString(rlp.encode(proof.accountProof)),
+    storageProof: toHexString(rlp.encode(proof.storageProof[0].proof)),
+  }
+}

yarn.lock

@@ -10920,6 +10920,17 @@ merkletreejs@^0.2.18:
     treeify "^1.1.0"
     web3-utils "^1.3.4"
 
+merkletreejs@^0.2.27:
+  version "0.2.27"
+  resolved "https://registry.yarnpkg.com/merkletreejs/-/merkletreejs-0.2.27.tgz#0691df1e1c80ebea7e35439dca5d9abd843b21d3"
+  integrity sha512-6fPGBdfbDyTiprK5JBBAxg+0u33xI3UM8EOeIz7Zy+5czuXH8vOhLMK1hMZFWPdCNgETWkpj+GOMKKhKZPOvaQ==
+  dependencies:
+    bignumber.js "^9.0.1"
+    buffer-reverse "^1.0.1"
+    crypto-js "^3.1.9-1"
+    treeify "^1.1.0"
+    web3-utils "^1.3.4"
+
 methods@^1.1.2, methods@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/methods/-/methods-1.1.2.tgz#5529a4d67654134edcc5266656835b0f851afcee"
@@ -13643,6 +13654,13 @@ rlp@^2.0.0, rlp@^2.2.1, rlp@^2.2.2, rlp@^2.2.3, rlp@^2.2.4, rlp@^2.2.6:
   dependencies:
     bn.js "^4.11.1"
 
+rlp@^2.2.7:
+  version "2.2.7"
+  resolved "https://registry.yarnpkg.com/rlp/-/rlp-2.2.7.tgz#33f31c4afac81124ac4b283e2bd4d9720b30beaf"
+  integrity sha512-d5gdPmgQ0Z+AklL2NVXr/IoSjNZFfTVvQWzL/AM2AOcSzYP2xjlb0AC8YyCLc41MSNf6P6QVtjgPdmVtzb+4lQ==
+  dependencies:
+    bn.js "^5.2.0"
+
 run-async@^2.2.0, run-async@^2.4.0:
   version "2.4.1"
   resolved "https://registry.yarnpkg.com/run-async/-/run-async-2.4.1.tgz#8440eccf99ea3e70bd409d49aab88e10c189a455"