Tx: New supports(capability) method

packages/block/src/block.ts

@@ -9,6 +9,7 @@ import {
   TxOptions,
   FeeMarketEIP1559Transaction,
   Transaction,
+  Capabilities,
 } from '@ethereumjs/tx'
 import { BlockHeader } from './header'
 import { BlockData, BlockOptions, JsonBlock, BlockBuffer, Blockchain } from './types'
@@ -161,7 +162,7 @@ export class Block {
     return [
       this.header.raw(),
       this.transactions.map((tx) =>
-        'transactionType' in tx && tx.transactionType > 0 ? tx.serialize() : tx.raw()
+        tx.supports(Capabilities.EIP2718TypedTransaction) ? tx.serialize() : tx.raw()
       ) as Buffer[],
       this.uncleHeaders.map((uh) => uh.raw()),
     ]
@@ -232,7 +233,7 @@ export class Block {
     this.transactions.forEach((tx, i) => {
       const errs = <string[]>tx.validate(true)
       if (this._common.isActivatedEIP(1559)) {
-        if (tx.transactionType === 2) {
+        if (tx.supports(Capabilities.EIP1559FeeMarket)) {
           tx = tx as FeeMarketEIP1559Transaction
           if (tx.maxFeePerGas.lt(this.header.baseFeePerGas!)) {
             errs.push('tx unable to pay base fee (EIP-1559 tx)')

packages/tx/src/baseTransaction.ts

@@ -18,6 +18,7 @@ import {
   FeeMarketEIP1559ValuesArray,
   FeeMarketEIP1559TxData,
   TxValuesArray,
+  Capabilities,
 } from './types'
 
 /**
@@ -42,6 +43,13 @@ export abstract class BaseTransaction<TransactionObject> {
 
   public readonly common!: Common
 
+  /**
+   * List of tx type defining EIPs,
+   * e.g. 1559 (fee market) and 2930 (access lists)
+   * for FeeMarketEIP1559Transaction objects
+   */
+  protected activeCapabilities: number[] = []
+
   /**
    * The default chain the tx falls back to if no Common
    * is provided and if the chain can't be derived from
@@ -106,6 +114,26 @@ export abstract class BaseTransaction<TransactionObject> {
     return this._type
   }
 
+  /**
+   * Checks if a tx type defining capability is active
+   * on a tx, for example the EIP-1559 fee market mechanism
+   * or the EIP-2930 access list feature.
+   *
+   * Note that this is different from the tx type itself,
+   * so EIP-2930 access lists can very well be active
+   * on an EIP-1559 tx for example.
+   *
+   * This method can be useful for feature checks if the
+   * tx type is unknown (e.g. when instantiated with
+   * the tx factory).
+   *
+   * See `Capabilites` in the `types` module for a reference
+   * on all supported capabilities.
+   */
+  supports(capability: Capabilities) {
+    return this.activeCapabilities.includes(capability)
+  }
+
   /**
    * Checks if the transaction has the minimum amount of gas required
    * (DataFee + TxFee + Creation Fee).
@@ -240,9 +268,34 @@ export abstract class BaseTransaction<TransactionObject> {
     if (privateKey.length !== 32) {
       throw new Error('Private key must be 32 bytes in length.')
     }
+
+    // Hack for the constellation that we have got a legacy tx after spuriousDragon with a non-EIP155 conforming signature
+    // and want to recreate a signature (where EIP155 should be applied)
+    // Leaving this hack lets the legacy.spec.ts -> sign(), verifySignature() test fail
+    // 2021-06-23
+    let hackApplied = false
+    if (
+      this.type === 0 &&
+      this.common.gteHardfork('spuriousDragon') &&
+      !this.supports(Capabilities.EIP155ReplayProtection)
+    ) {
+      this.activeCapabilities.push(Capabilities.EIP155ReplayProtection)
+      hackApplied = true
+    }
+
     const msgHash = this.getMessageToSign(true)
     const { v, r, s } = ecsign(msgHash, privateKey)
-    return this._processSignature(v, r, s)
+    const tx = this._processSignature(v, r, s)
+
+    // Hack part 2
+    if (hackApplied) {
+      const index = this.activeCapabilities.indexOf(Capabilities.EIP155ReplayProtection)
+      if (index > -1) {
+        this.activeCapabilities.splice(index, 1)
+      }
+    }
+
+    return tx
   }
 
   /**

packages/tx/src/eip1559Transaction.ts

@@ -188,6 +188,7 @@ export default class FeeMarketEIP1559Transaction extends BaseTransaction<FeeMark
     if (!this.common.isActivatedEIP(1559)) {
       throw new Error('EIP-1559 not enabled on Common')
     }
+    this.activeCapabilities = this.activeCapabilities.concat([1559, 2718, 2930])
 
     // Populate the access list fields
     const accessListData = AccessLists.getAccessListData(accessList ?? [])

packages/tx/src/eip2930Transaction.ts

@@ -177,6 +177,7 @@ export default class AccessListEIP2930Transaction extends BaseTransaction<Access
     if (!this.common.isActivatedEIP(2930)) {
       throw new Error('EIP-2930 not enabled on Common')
     }
+    this.activeCapabilities = this.activeCapabilities.concat([2718, 2930])
 
     // Populate the access list fields
     const accessListData = AccessLists.getAccessListData(accessList ?? [])

packages/tx/src/legacyTransaction.ts

@@ -8,7 +8,7 @@ import {
   toBuffer,
   unpadBuffer,
 } from 'ethereumjs-util'
-import { TxOptions, TxData, JsonTx, N_DIV_2, TxValuesArray } from './types'
+import { TxOptions, TxData, JsonTx, N_DIV_2, TxValuesArray, Capabilities } from './types'
 import { BaseTransaction } from './baseTransaction'
 import Common from '@ethereumjs/common'
 
@@ -108,6 +108,25 @@ export default class Transaction extends BaseTransaction<Transaction> {
 
     this._validateCannotExceedMaxInteger({ gasPrice: this.gasPrice })
 
+    if (this.common.gteHardfork('spuriousDragon')) {
+      if (!this.isSigned()) {
+        this.activeCapabilities.push(Capabilities.EIP155ReplayProtection)
+      } else {
+        // EIP155 spec:
+        // If block.number >= 2,675,000 and v = CHAIN_ID * 2 + 35 or v = CHAIN_ID * 2 + 36
+        // then when computing the hash of a transaction for purposes of signing or recovering
+        // instead of hashing only the first six elements (i.e. nonce, gasprice, startgas, to, value, data)
+        // hash nine elements, with v replaced by CHAIN_ID, r = 0 and s = 0.
+        const v = this.v!
+        const chainIdDoubled = this.common.chainIdBN().muln(2)
+
+        // v and chain ID meet EIP-155 conditions
+        if (v.eq(chainIdDoubled.addn(35)) || v.eq(chainIdDoubled.addn(36))) {
+          this.activeCapabilities.push(Capabilities.EIP155ReplayProtection)
+        }
+      }
+    }
+
     const freeze = opts?.freeze ?? true
     if (freeze) {
       Object.freeze(this)
@@ -150,11 +169,7 @@ export default class Transaction extends BaseTransaction<Transaction> {
     return rlp.encode(this.raw())
   }
 
-  private _unsignedTxImplementsEIP155() {
-    return this.common.gteHardfork('spuriousDragon')
-  }
-
-  private _getMessageToSign(withEIP155: boolean) {
+  private _getMessageToSign() {
     const values = [
       bnToUnpaddedBuffer(this.nonce),
       bnToUnpaddedBuffer(this.gasPrice),
@@ -164,7 +179,7 @@ export default class Transaction extends BaseTransaction<Transaction> {
       this.data,
     ]
 
-    if (withEIP155) {
+    if (this.supports(Capabilities.EIP155ReplayProtection)) {
       values.push(toBuffer(this.common.chainIdBN()))
       values.push(unpadBuffer(toBuffer(0)))
       values.push(unpadBuffer(toBuffer(0)))
@@ -191,7 +206,7 @@ export default class Transaction extends BaseTransaction<Transaction> {
   getMessageToSign(hashMessage: false): Buffer[]
   getMessageToSign(hashMessage?: true): Buffer
   getMessageToSign(hashMessage = true) {
-    const message = this._getMessageToSign(this._unsignedTxImplementsEIP155())
+    const message = this._getMessageToSign()
     if (hashMessage) {
       return rlphash(message)
     } else {
@@ -220,8 +235,10 @@ export default class Transaction extends BaseTransaction<Transaction> {
    * Computes a sha3-256 hash which can be used to verify the signature
    */
   getMessageToVerifySignature() {
-    const withEIP155 = this._signedTxImplementsEIP155()
-    const message = this._getMessageToSign(withEIP155)
+    if (!this.isSigned()) {
+      throw Error('This transaction is not signed')
+    }
+    const message = this._getMessageToSign()
     return rlphash(message)
   }
 
@@ -246,7 +263,7 @@ export default class Transaction extends BaseTransaction<Transaction> {
         v!,
         bnToUnpaddedBuffer(r!),
         bnToUnpaddedBuffer(s!),
-        this._signedTxImplementsEIP155() ? this.common.chainIdBN() : undefined
+        this.supports(Capabilities.EIP155ReplayProtection) ? this.common.chainIdBN() : undefined
       )
     } catch (e) {
       throw new Error('Invalid Signature')
@@ -258,7 +275,7 @@ export default class Transaction extends BaseTransaction<Transaction> {
    */
   protected _processSignature(v: number, r: Buffer, s: Buffer) {
     const vBN = new BN(v)
-    if (this._unsignedTxImplementsEIP155()) {
+    if (this.supports(Capabilities.EIP155ReplayProtection)) {
       vBN.iadd(this.common.chainIdBN().muln(2).addn(8))
     }
 
@@ -338,11 +355,20 @@ export default class Transaction extends BaseTransaction<Transaction> {
     return this._getCommon(common, chainIdBN)
   }
 
+  /**
+   * @deprecated if you have called this internal method please use `tx.supports(Capabilities.EIP155ReplayProtection)` instead
+   */
+  private _unsignedTxImplementsEIP155() {
+    return this.common.gteHardfork('spuriousDragon')
+  }
+
+  /**
+   * @deprecated if you have called this internal method please use `tx.supports(Capabilities.EIP155ReplayProtection)` instead
+   */
   private _signedTxImplementsEIP155() {
     if (!this.isSigned()) {
       throw Error('This transaction is not signed')
     }
-
     const onEIP155BlockOrLater = this.common.gteHardfork('spuriousDragon')
 
     // EIP155 spec:

packages/tx/src/types.ts

@@ -4,6 +4,36 @@ import { default as Transaction } from './legacyTransaction'
 import { default as AccessListEIP2930Transaction } from './eip2930Transaction'
 import { default as FeeMarketEIP1559Transaction } from './eip1559Transaction'
 
+/**
+ * Can be used in conjunction with the `supports()` function
+ * to query on tx capabilities
+ */
+export enum Capabilities {
+  /**
+   * Tx supports EIP-155 replay protection
+   * See: [155](https://eips.ethereum.org/EIPS/eip-155) Replay Attack Protection EIP
+   */
+  EIP155ReplayProtection = 155,
+
+  /**
+   * Tx supports EIP-1559 gas fee market mechansim
+   * See: [1559](https://eips.ethereum.org/EIPS/eip-1559) Fee Market EIP
+   */
+  EIP1559FeeMarket = 1559,
+
+  /**
+   * Tx is a typed transaction as defined in EIP-2718
+   * See: [2718](https://eips.ethereum.org/EIPS/eip-2718) Transaction Type EIP
+   */
+  EIP2718TypedTransaction = 2718,
+
+  /**
+   * Tx supports access list generation as defined in EIP-2930
+   * See: [2930](https://eips.ethereum.org/EIPS/eip-2930) Access Lists EIP
+   */
+  EIP2930AccessLists = 2930,
+}
+
 /**
  * The options for initializing a Transaction.
  */

packages/tx/test/base.spec.ts

@@ -5,6 +5,7 @@ import {
   AccessListEIP2930Transaction,
   FeeMarketEIP1559Transaction,
   N_DIV_2,
+  Capabilities,
 } from '../src'
 import { TxsJsonEntry } from './types'
 import { BaseTransaction } from '../src/baseTransaction'
@@ -41,6 +42,13 @@ tape('[BaseTransaction]', function (t) {
       values: Array(6).fill(zero),
       txs: legacyTxs,
       fixtures: legacyFixtures,
+      activeCapabilities: [],
+      notActiveCapabilities: [
+        Capabilities.EIP1559FeeMarket,
+        Capabilities.EIP2718TypedTransaction,
+        Capabilities.EIP2930AccessLists,
+        9999,
+      ],
     },
     {
       class: AccessListEIP2930Transaction,
@@ -49,6 +57,8 @@ tape('[BaseTransaction]', function (t) {
       values: [Buffer.from([1])].concat(Array(7).fill(zero)),
       txs: eip2930Txs,
       fixtures: eip2930Fixtures,
+      activeCapabilities: [Capabilities.EIP2718TypedTransaction, Capabilities.EIP2930AccessLists],
+      notActiveCapabilities: [Capabilities.EIP1559FeeMarket, 9999],
     },
     {
       class: FeeMarketEIP1559Transaction,
@@ -57,6 +67,12 @@ tape('[BaseTransaction]', function (t) {
       values: [Buffer.from([1])].concat(Array(8).fill(zero)),
       txs: eip1559Txs,
       fixtures: eip1559Fixtures,
+      activeCapabilities: [
+        Capabilities.EIP1559FeeMarket,
+        Capabilities.EIP2718TypedTransaction,
+        Capabilities.EIP2930AccessLists,
+      ],
+      notActiveCapabilities: [9999],
     },
   ]
 
@@ -150,6 +166,26 @@ tape('[BaseTransaction]', function (t) {
     st.end()
   })
 
+  t.test('supports()', function (st) {
+    for (const txType of txTypes) {
+      txType.txs.forEach(function (tx: any) {
+        for (const activeCapability of txType.activeCapabilities) {
+          st.ok(
+            tx.supports(activeCapability),
+            `${txType.name}: should recognize all supported capabilities`
+          )
+        }
+        for (const notActiveCapability of txType.notActiveCapabilities) {
+          st.notOk(
+            tx.supports(notActiveCapability),
+            `${txType.name}: should reject non-active existing and not existing capabilities`
+          )
+        }
+      })
+    }
+    st.end()
+  })
+
   t.test('raw()', function (st) {
     for (const txType of txTypes) {
       txType.txs.forEach(function (tx: any) {