nimbus-eth1/nimbus/core/eip4844.nim

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# Nimbus
# Copyright (c) 2023-2024 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
# http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
# http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except
# according to those terms.
import
std/[os, strutils],
nimcrypto/sha2,
kzg4844/kzg_ex as kzg,
stew/results,
stint,
../constants,
../common/common
{.push raises: [].}
type
Bytes32 = array[32, byte]
Bytes64 = array[64, byte]
Bytes48 = array[48, byte]
const
BLS_MODULUS_STR = "52435875175126190479447740508185965837690552500527637822603658699938581184513"
BLS_MODULUS* = parse(BLS_MODULUS_STR, UInt256, 10).toBytesBE
PrecompileInputLength = 192
proc pointEvaluationResult(): Bytes64 {.compileTime.} =
result[0..<32] = FIELD_ELEMENTS_PER_BLOB.u256.toBytesBE[0..^1]
result[32..^1] = BLS_MODULUS[0..^1]
const
PointEvaluationResult* = pointEvaluationResult()
POINT_EVALUATION_PRECOMPILE_GAS* = 50000.GasInt
# kzgToVersionedHash implements kzg_to_versioned_hash from EIP-4844
proc kzgToVersionedHash*(kzg: kzg.KZGCommitment): VersionedHash =
result = sha256.digest(kzg)
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result.data[0] = VERSIONED_HASH_VERSION_KZG
# pointEvaluation implements point_evaluation_precompile from EIP-4844
# return value and gas consumption is handled by pointEvaluation in
# precompiles.nim
proc pointEvaluation*(input: openArray[byte]): Result[void, string] =
# Verify p(z) = y given commitment that corresponds to the polynomial p(x) and a KZG proof.
# Also verify that the provided commitment matches the provided versioned_hash.
# The data is encoded as follows: versioned_hash | z | y | commitment | proof |
if input.len != PrecompileInputLength:
return err("invalid input length")
var
versionedHash: Bytes32
z: Bytes32
y: Bytes32
commitment: Bytes48
kzgProof: Bytes48
versionedHash[0..<32] = input[0..<32]
z[0..<32] = input[32..<64]
y[0..<32] = input[64..<96]
commitment[0..<48] = input[96..<144]
kzgProof[0..<48] = input[144..<192]
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if kzgToVersionedHash(commitment).data != versionedHash:
return err("versionedHash should equal to kzgToVersionedHash(commitment)")
# Verify KZG proof
let res = kzg.verifyKzgProof(commitment, z, y, kzgProof)
if res.isErr:
return err(res.error)
# The actual verify result
if not res.get():
return err("Failed to verify KZG proof")
ok()
# calcExcessBlobGas implements calc_excess_data_gas from EIP-4844
proc calcExcessBlobGas*(parent: BlockHeader): uint64 =
let
excessBlobGas = parent.excessBlobGas.get(0'u64)
blobGasUsed = parent.blobGasUsed.get(0'u64)
if excessBlobGas + blobGasUsed < TARGET_BLOB_GAS_PER_BLOCK:
0'u64
else:
excessBlobGas + blobGasUsed - TARGET_BLOB_GAS_PER_BLOCK
# fakeExponential approximates factor * e ** (num / denom) using a taylor expansion
# as described in the EIP-4844 spec.
func fakeExponential*(factor, numerator, denominator: UInt256): UInt256 =
var
i = 1.u256
output = 0.u256
numeratorAccum = factor * denominator
while numeratorAccum > 0.u256:
output += numeratorAccum
numeratorAccum = (numeratorAccum * numerator) div (denominator * i)
i = i + 1.u256
output div denominator
proc getTotalBlobGas*(tx: Transaction): uint64 =
GAS_PER_BLOB * tx.versionedHashes.len.uint64
proc getTotalBlobGas*(versionedHashesLen: int): uint64 =
GAS_PER_BLOB * versionedHashesLen.uint64
# getBlobBaseFee implements get_data_gas_price from EIP-4844
func getBlobBaseFee*(excessBlobGas: uint64): UInt256 =
fakeExponential(
MIN_BLOB_GASPRICE.u256,
excessBlobGas.u256,
BLOB_GASPRICE_UPDATE_FRACTION.u256
)
proc calcDataFee*(versionedHashesLen: int,
excessBlobGas: uint64): UInt256 =
getTotalBlobGas(versionedHashesLen).u256 *
getBlobBaseFee(excessBlobGas)
func blobGasUsed(txs: openArray[Transaction]): uint64 =
for tx in txs:
result += tx.getTotalBlobGas
# https://eips.ethereum.org/EIPS/eip-4844
func validateEip4844Header*(
com: CommonRef, header, parentHeader: BlockHeader,
txs: openArray[Transaction]): Result[void, string] {.raises: [].} =
if not com.forkGTE(Cancun):
if header.blobGasUsed.isSome:
return err("unexpected EIP-4844 blobGasUsed in block header")
if header.excessBlobGas.isSome:
return err("unexpected EIP-4844 excessBlobGas in block header")
return ok()
if header.blobGasUsed.isNone:
return err("expect EIP-4844 blobGasUsed in block header")
if header.excessBlobGas.isNone:
return err("expect EIP-4844 excessBlobGas in block header")
let
headerBlobGasUsed = header.blobGasUsed.get()
blobGasUsed = blobGasUsed(txs)
headerExcessBlobGas = header.excessBlobGas.get
excessBlobGas = calcExcessBlobGas(parentHeader)
if blobGasUsed > MAX_BLOB_GAS_PER_BLOCK:
return err("blobGasUsed " & $blobGasUsed & " exceeds maximum allowance " & $MAX_BLOB_GAS_PER_BLOCK)
if headerBlobGasUsed != blobGasUsed:
return err("calculated blobGas not equal header.blobGasUsed")
if headerExcessBlobGas != excessBlobGas:
return err("calculated excessBlobGas not equal header.excessBlobGas")
return ok()
proc validateBlobTransactionWrapper*(tx: PooledTransaction):
Result[void, string] {.raises: [].} =
if tx.networkPayload.isNil:
return err("tx wrapper is none")
# note: assert blobs are not malformatted
let goodFormatted = tx.tx.versionedHashes.len ==
tx.networkPayload.commitments.len and
tx.tx.versionedHashes.len ==
tx.networkPayload.blobs.len and
tx.tx.versionedHashes.len ==
tx.networkPayload.proofs.len
if not goodFormatted:
return err("tx wrapper is ill formatted")
# Verify that commitments match the blobs by checking the KZG proof
let res = kzg.verifyBlobKzgProofBatch(tx.networkPayload.blobs,
tx.networkPayload.commitments, tx.networkPayload.proofs)
if res.isErr:
return err(res.error)
# Actual verification result
if not res.get():
return err("Failed to verify network payload of a transaction")
# Now that all commitments have been verified, check that versionedHashes matches the commitments
for i in 0 ..< tx.tx.versionedHashes.len:
# this additional check also done in tx validation
if tx.tx.versionedHashes[i].data[0] != VERSIONED_HASH_VERSION_KZG:
return err("wrong kzg version in versioned hash at index " & $i)
if tx.tx.versionedHashes[i] !=
kzgToVersionedHash(tx.networkPayload.commitments[i]):
return err("tx versioned hash not match commitments at index " & $i)
ok()
proc loadKzgTrustedSetup*(): Result[void, string] =
const
vendorDir = currentSourcePath.parentDir.replace('\\', '/') & "/../../vendor"
trustedSetupDir = vendorDir & "/nim-kzg4844/kzg4844/csources/src"
trustedSetup = staticRead trustedSetupDir & "/trusted_setup.txt"
Kzg.loadTrustedSetupFromString(trustedSetup)