define Electra types and RLP encoding (#711)

Add types for EIP-6110, EIP-7002 and EIP-7251 validator operations.

eth/common/eth_types.nim

@@ -23,6 +23,11 @@ export
   eth_hash,
   eth_times
 
+const
+  DEPOSIT_REQUEST_TYPE* = 0x00'u8  # EIP-6110
+  WITHDRAWAL_REQUEST_TYPE* = 0x01'u8  # EIP-7002
+  CONSOLIDATION_REQUEST_TYPE* = 0x02'u8  # EIP-7251
+
 type
   Hash256* = MDigest[256]
   VMWord* = UInt256
@@ -124,6 +129,23 @@ type
     address*       : EthAddress
     amount*        : uint64
 
+  DepositRequest* = object  # EIP-6110
+    pubkey*               : array[48, byte]
+    withdrawalCredentials*: array[32, byte]
+    amount*               : uint64
+    signature*            : array[96, byte]
+    index*                : uint64
+
+  WithdrawalRequest* = object  # EIP-7002
+    sourceAddress*  : array[20, byte]
+    validatorPubkey*: array[48, byte]
+    amount*         : uint64
+
+  ConsolidationRequest* = object  # EIP-7251
+    sourceAddress*: array[20, byte]
+    sourcePubkey* : array[48, byte]
+    targetPubkey* : array[48, byte]
+
   # https://eips.ethereum.org/EIPS/eip-4844#header-extension
   BlockHeader* = object
     parentHash*:      Hash256
@@ -146,6 +168,7 @@ type
     blobGasUsed*:     Opt[uint64]    # EIP-4844
     excessBlobGas*:   Opt[uint64]    # EIP-4844
     parentBeaconBlockRoot*: Opt[Hash256] # EIP-4788
+    requestsRoot*:    Opt[Hash256]  # EIP-7685
 
   BlockBody* = object
     transactions*:  seq[Transaction]

eth/common/eth_types_rlp.nim

@@ -527,6 +527,85 @@ proc read*(rlp: var Rlp, T: type HashOrNum): T =
 proc append*(rlpWriter: var RlpWriter, t: EthTime) {.inline.} =
   rlpWriter.append(t.uint64)
 
+proc append*(rlpWriter: var RlpWriter, request: DepositRequest) =
+  rlpWriter.appendRawBytes([DEPOSIT_REQUEST_TYPE])
+  rlpWriter.startList(5)
+  rlpWriter.append(request.pubkey)
+  rlpWriter.append(request.withdrawalCredentials)
+  rlpWriter.append(request.amount)
+  rlpWriter.append(request.signature)
+  rlpWriter.append(request.index)
+
+proc read*(rlp: var Rlp, T: type DepositRequest): T =
+  if not rlp.hasData:
+    raise (ref MalformedRlpError)(msg:
+      "DEPOSIT_REQUEST_TYPE expected but source RLP is empty")
+  let reqType = rlp.readRawByte()
+  if reqType != DEPOSIT_REQUEST_TYPE:
+    raise (ref UnsupportedRlpError)(msg:
+      "Unexpected DEPOSIT_REQUEST_TYPE: " & $reqType)
+
+  var res: DepositRequest
+  rlp.tryEnterList()
+  rlp.read(res.pubkey)
+  rlp.read(res.withdrawalCredentials)
+  rlp.read(res.amount)
+  rlp.read(res.signature)
+  rlp.read(res.index)
+  if rlp.hasData:
+    raise (ref MalformedRlpError)(msg: "Extra data after DepositRequest")
+  res
+
+proc append*(rlpWriter: var RlpWriter, request: WithdrawalRequest) =
+  rlpWriter.appendRawBytes([WITHDRAWAL_REQUEST_TYPE])
+  rlpWriter.startList(3)
+  rlpWriter.append(request.sourceAddress)
+  rlpWriter.append(request.validatorPubkey)
+  rlpWriter.append(request.amount)
+
+proc read*(rlp: var Rlp, T: type WithdrawalRequest): T =
+  if not rlp.hasData:
+    raise (ref MalformedRlpError)(msg:
+      "WITHDRAWAL_REQUEST_TYPE expected but source RLP is empty")
+  let reqType = rlp.readRawByte()
+  if reqType != WITHDRAWAL_REQUEST_TYPE:
+    raise (ref UnsupportedRlpError)(msg:
+      "Unexpected WITHDRAWAL_REQUEST_TYPE: " & $reqType)
+
+  var res: WithdrawalRequest
+  rlp.tryEnterList()
+  rlp.read(res.sourceAddress)
+  rlp.read(res.validatorPubkey)
+  rlp.read(res.amount)
+  if rlp.hasData:
+    raise (ref MalformedRlpError)(msg: "Extra data after WithdrawalRequest")
+  res
+
+proc append*(rlpWriter: var RlpWriter, request: ConsolidationRequest) =
+  rlpWriter.appendRawBytes([CONSOLIDATION_REQUEST_TYPE])
+  rlpWriter.startList(3)
+  rlpWriter.append(request.sourceAddress)
+  rlpWriter.append(request.sourcePubkey)
+  rlpWriter.append(request.targetPubkey)
+
+proc read*(rlp: var Rlp, T: type ConsolidationRequest): T =
+  if not rlp.hasData:
+    raise (ref MalformedRlpError)(msg:
+      "CONSOLIDATION_REQUEST_TYPE expected but source RLP is empty")
+  let reqType = rlp.readRawByte()
+  if reqType != CONSOLIDATION_REQUEST_TYPE:
+    raise (ref UnsupportedRlpError)(msg:
+      "Unexpected CONSOLIDATION_REQUEST_TYPE: " & $reqType)
+
+  var res: ConsolidationRequest
+  rlp.tryEnterList()
+  rlp.read(res.sourceAddress)
+  rlp.read(res.sourcePubkey)
+  rlp.read(res.targetPubkey)
+  if rlp.hasData:
+    raise (ref MalformedRlpError)(msg: "Extra data after ConsolidationRequest")
+  res
+
 proc rlpHash*[T](v: T): Hash256 =
   keccakHash(rlp.encode(v))
 

eth/rlp.nim

@@ -217,6 +217,14 @@ func getByteValue*(self: Rlp): byte =
   doAssert self.isSingleByte()
   self.bytes[self.position]
 
+func readRawByte*(self: var Rlp): byte =
+  ### Read a raw byte that is not RLP encoded
+  ### This is sometimes used to communicate union type information
+  doAssert self.hasData
+  let res = self.bytes[self.position]
+  inc self.position
+  res
+
 func blobLen*(self: Rlp): int =
   if self.isBlob():
     self.item().payload.len()