444 lines
16 KiB
Nim
444 lines
16 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2024 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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{.push raises: [].}
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# Uncategorized helper functions from the spec
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import
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std/[algorithm, macros, tables],
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stew/results,
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ssz_serialization/[
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proofs,
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types],
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chronicles,
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./[beacon_time, crypto],
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kzg4844/kzg_ex,
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eth/p2p/discoveryv5/[node],
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./helpers,
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./datatypes/[eip7594, deneb]
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type
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CellBytes = array[eip7594.CELLS_PER_EXT_BLOB, Cell]
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ProofBytes = array[eip7594.CELLS_PER_EXT_BLOB, KzgProof]
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proc sortedColumnIndices*(columnsPerSubnet: ColumnIndex,
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subnetIds: HashSet[uint64]):
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seq[ColumnIndex] =
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var res: seq[ColumnIndex] = @[]
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for i in 0'u64 ..< columnsPerSubnet:
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for subnetId in subnetIds:
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let index = DATA_COLUMN_SIDECAR_SUBNET_COUNT * i + subnetId
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res.add(ColumnIndex(index))
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res.sort
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res
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proc sortedColumnIndexList*(columnsPerSubnet: ColumnIndex,
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subnetIds: HashSet[uint64]):
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List[ColumnIndex, NUMBER_OF_COLUMNS] =
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var
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res: seq[ColumnIndex]
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for i in 0'u64 ..< columnsPerSubnet:
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for subnetId in subnetIds:
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let index = DATA_COLUMN_SIDECAR_SUBNET_COUNT * i + subnetId
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res.add(ColumnIndex(index))
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res.sort()
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let list = List[ColumnIndex, NUMBER_OF_COLUMNS].init(res)
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list
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proc get_custody_column_subnets*(node_id: NodeId,
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custody_subnet_count: uint64):
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Result[HashSet[uint64], cstring] =
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# Decouples the custody subnet computation part from
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# `get_custody_columns`, in order to later use this subnet list
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# in order to maintain subscription to specific column subnets.
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if not (custody_subnet_count <= DATA_COLUMN_SIDECAR_SUBNET_COUNT):
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return err("Eip7594: Custody subnet count exceeds the DATA_COLUMN_SIDECAR_SUBNET_COUNT")
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var
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subnet_ids: HashSet[uint64]
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current_id = node_id
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while subnet_ids.lenu64 < custody_subnet_count:
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var
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hashed_bytes: array[8, byte]
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let
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current_id_bytes = current_id.toBytesLE()
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hashed_current_id = eth2digest(current_id_bytes)
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hashed_bytes[0..7] = hashed_current_id.data.toOpenArray(0,7)
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let subnet_id = bytes_to_uint64(hashed_bytes) mod
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DATA_COLUMN_SIDECAR_SUBNET_COUNT
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subnet_ids.incl(subnet_id)
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if current_id == UInt256.high.NodeId:
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# Overflow prevention
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current_id = NodeId(StUint[256].zero)
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current_id += NodeId(StUint[256].one)
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ok(subnet_ids)
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# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.5/specs/_features/eip7594/das-core.md#get_custody_columns
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proc get_custody_columns*(node_id: NodeId,
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custody_subnet_count: uint64):
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seq[ColumnIndex] =
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let
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subnet_ids =
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get_custody_column_subnets(node_id, custody_subnet_count).get
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const
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columns_per_subnet =
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NUMBER_OF_COLUMNS div DATA_COLUMN_SIDECAR_SUBNET_COUNT
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sortedColumnIndices(ColumnIndex(columns_per_subnet), subnet_ids)
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proc get_custody_column_list*(node_id: NodeId,
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custody_subnet_count: uint64):
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List[ColumnIndex, NUMBER_OF_COLUMNS] =
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# Not in spec in the exact format, but it is useful in sorting custody columns
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# before sending, data_column_sidecars_by_range requests
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let
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subnet_ids =
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get_custody_column_subnets(node_id, custody_subnet_count).get
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const
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columns_per_subnet =
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NUMBER_OF_COLUMNS div DATA_COLUMN_SIDECAR_SUBNET_COUNT
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sortedColumnIndexList(ColumnIndex(columns_per_subnet), subnet_ids)
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# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.3/specs/_features/eip7594/das-core.md#compute_extended_matrix
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proc compute_extended_matrix* (blobs: seq[KzgBlob]): Result[seq[MatrixEntry], cstring] =
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# This helper demonstrates the relationship between blobs and the `MatrixEntries`
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var extended_matrix: seq[MatrixEntry]
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for blbIdx, blob in blobs.pairs:
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let cellsAndProofs = computeCellsAndKzgProofs(blob)
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if not cellsAndProofs.isOk:
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return err("Computing Extended Matrix: Issue computing cells and proofs")
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for i in 0..<eip7594.CELLS_PER_EXT_BLOB:
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extended_matrix.add(MatrixEntry(
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cell: cellsAndProofs.get.cells[i],
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kzg_proof: cellsAndProofs.get.proofs[i],
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row_index: blbIdx.uint64,
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column_index: i.uint64
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))
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ok(extended_matrix)
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# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.3/specs/_features/eip7594/das-core.md#recover_matrix
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proc recover_matrix*(partial_matrix: seq[MatrixEntry],
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blobCount: int):
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Result[seq[MatrixEntry], cstring] =
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# This helper demonstrates how to apply recover_cells_and_kzg_proofs
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# The data structure for storing cells is implementation-dependent
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var extended_matrix: seq[MatrixEntry]
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for blob_index in 0..<blobCount:
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var
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cell_indices: seq[CellID]
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cells: seq[Cell]
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for e in partial_matrix:
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if e.row_index == uint64(blob_index):
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cell_indices.add(e.column_index)
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cells.add(e.cell)
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let recoveredCellsAndKzgProofs =
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recoverCellsAndKzgProofs(cell_indices, cells)
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if not recoveredCellsAndKzgProofs.isOk:
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return err("Issue in recovering cells and proofs")
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for i in 0..<recoveredCellsAndKzgProofs.get.cells.len:
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let
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cell = recoveredCellsAndKzgProofs.get.cells[i]
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proof = recoveredCellsAndKzgProofs.get.proofs[i]
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extended_matrix.add(MatrixEntry(
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cell: cell,
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kzg_proof: proof,
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row_index: blob_index.uint64,
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column_index: i.uint64
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))
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ok(extended_matrix)
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# THIS METHOD IS DEPRECATED, WILL BE REMOVED ONCE ALPHA 4 IS RELEASED
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proc recover_cells_and_proofs*(
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data_columns: seq[DataColumnSidecar],
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columnCount: int,
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blck: deneb.TrustedSignedBeaconBlock |
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electra.TrustedSignedBeaconBlock |
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ForkedTrustedSignedBeaconBlock):
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Result[seq[CellsAndProofs], cstring] =
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# This helper recovers blobs from the data column sidecars
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if not (data_columns.len != 0):
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return err("DataColumnSidecar: Length should not be 0")
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var blobCount = data_columns[0].column.len
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for data_column in data_columns:
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if not (blobCount == data_column.column.len):
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return err ("DataColumns do not have the same length")
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var
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recovered_cps = newSeq[CellsAndProofs](blobCount)
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for blobIdx in 0 ..< blobCount:
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var
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bIdx = blobIdx
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cell_ids = newSeq[CellID](columnCount)
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ckzgCells = newSeq[KzgCell](columnCount)
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for i in 0..<data_columns.len:
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cell_ids[i] = data_columns[i].index
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let
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column = data_columns[i].column
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cell = column[bIdx]
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ckzgCells[i] = cell
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# Recovering the cells and proofs
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let recovered_cells_and_proofs = recoverCellsAndKzgProofs(cell_ids, ckzgCells)
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if not recovered_cells_and_proofs.isOk:
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return err("Issue with computing cells and proofs!")
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recovered_cps[blobIdx] = recovered_cells_and_proofs.get
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ok(recovered_cps)
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proc compute_signed_block_header(signed_block: deneb.TrustedSignedBeaconBlock |
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electra.TrustedSignedBeaconBlock):
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SignedBeaconBlockHeader =
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let blck = signed_block.message
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let block_header = BeaconBlockHeader(
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slot: blck.slot,
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proposer_index: blck.proposer_index,
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parent_root: blck.parent_root,
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state_root: blck.state_root,
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body_root: hash_tree_root(blck.body)
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)
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result = SignedBeaconBlockHeader(
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message: block_header,
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signature: signed_block.signature.toValidatorSig
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)
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proc compute_signed_block_header(signed_block: deneb.SignedBeaconBlock |
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electra.SignedBeaconBlock):
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SignedBeaconBlockHeader =
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let blck = signed_block.message
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let block_header = BeaconBlockHeader(
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slot: blck.slot,
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proposer_index: blck.proposer_index,
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parent_root: blck.parent_root,
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state_root: blck.state_root,
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body_root: hash_tree_root(blck.body)
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)
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result = SignedBeaconBlockHeader(
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message: block_header,
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signature: signed_block.signature
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)
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# https://github.com/ethereum/consensus-specs/blob/bb8f3caafc92590cdcf2d14974adb602db9b5ca3/specs/_features/eip7594/das-core.md#get_data_column_sidecars
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proc get_data_column_sidecars*(signed_block: deneb.TrustedSignedBeaconBlock |
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deneb.SignedBeaconBlock |
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electra.TrustedSignedBeaconBlock |
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electra.SignedBeaconBlock,
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cellsAndProofs: seq[CellsAndProofs]):
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Result[seq[DataColumnSidecar], string] =
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# Given a signed block and the cells/proofs associated with each blob
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# in the block, assemble the sidecars which can be distributed to peers.
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var
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blck = signed_block.message
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signed_beacon_block_header =
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compute_signed_block_header(signed_block)
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kzg_incl_proof: array[4, Eth2Digest]
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var sidecars = newSeqOfCap[DataColumnSidecar](CELLS_PER_EXT_BLOB)
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if cellsAndProofs.len == 0:
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return ok(sidecars)
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for column_index in 0..<NUMBER_OF_COLUMNS:
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var
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column_cells: DataColumn
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column_proofs: KzgProofs
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for i in 0..<cellsAndProofs.len:
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discard column_cells.add(cellsAndProofs[i].cells)
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discard column_proofs.add(cellsAndProofs[i].proofs)
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var sidecar = DataColumnSidecar(
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index: ColumnIndex(column_index),
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column: column_cells,
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kzg_commitments: blck.body.blob_kzg_commitments,
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kzg_proofs: column_proofs,
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signed_block_header: signed_beacon_block_header)
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blck.body.build_proof(
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27.GeneralizedIndex,
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sidecar.kzg_commitments_inclusion_proof).expect("Valid gindex")
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sidecars.add(sidecar)
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ok(sidecars)
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# https://github.com/ethereum/consensus-specs/blob/5f48840f4d768bf0e0a8156a3ed06ec333589007/specs/_features/eip7594/das-core.md#get_data_column_sidecars
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proc get_data_column_sidecars*(signed_block: deneb.SignedBeaconBlock |
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electra.SignedBeaconBlock,
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blobs: seq[KzgBlob]):
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Result[seq[DataColumnSidecar], string] =
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var
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blck = signed_block.message
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signed_beacon_block_header = compute_signed_block_header(signed_block)
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kzg_incl_proof: array[4, Eth2Digest]
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var sidecars = newSeqOfCap[DataColumnSidecar](CELLS_PER_EXT_BLOB)
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if blobs.len == 0:
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return ok(sidecars)
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var
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cells = newSeq[CellBytes](blobs.len)
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proofs = newSeq[ProofBytes](blobs.len)
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for i in 0..<blobs.len:
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let
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cell_and_proof = computeCellsAndProofs(blobs[i])
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if cell_and_proof.isErr():
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return err("EIP7549: Could not compute cells")
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cells[i] = cell_and_proof.get.cells
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proofs[i] = cell_and_proof.get.proofs
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let blobCount = blobs.len
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for columnIndex in 0..<CELLS_PER_EXT_BLOB:
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var
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column: DataColumn
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kzgProofOfColumn: KzgProofs
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for rowIndex in 0..<blobCount:
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discard column.add(cells[rowIndex][columnIndex])
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for rowIndex in 0..<blobCount:
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discard kzgProofOfColumn.add(proofs[rowIndex][columnIndex])
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var sidecar = DataColumnSidecar(
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index: ColumnIndex(columnIndex),
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column: DataColumn(column),
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kzg_commitments: blck.body.blob_kzg_commitments,
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kzg_proofs: KzgProofs(kzgProofOfColumn),
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signed_block_header: signed_beacon_block_header)
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blck.body.build_proof(
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27.GeneralizedIndex,
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sidecar.kzg_commitments_inclusion_proof).expect("Valid gindex")
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sidecars.add(sidecar)
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ok(sidecars)
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# Helper function to `verifyCellKzgProofBatch` at https://github.com/ethereum/c-kzg-4844/blob/das/bindings/nim/kzg_ex.nim#L170
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proc validate_data_column_sidecar*(
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expected_commitments: seq[KzgCommitment],
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cellIndex: seq[CellIndex],
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column: seq[Cell],
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proofs: seq[KzgProof]): Result[void, string] =
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let res = verifyCellKzgProofBatch(expected_commitments, cellIndex, column, proofs).valueOr:
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return err("DataColumnSidecar: Proof verification error: " & error())
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if not res:
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return err("DataColumnSidecar: Proof verification failed")
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ok()
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# https://github.com/ethereum/consensus-specs/blob/5f48840f4d768bf0e0a8156a3ed06ec333589007/specs/_features/eip7594/p2p-interface.md#verify_data_column_sidecar_kzg_proofs
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proc verify_data_column_sidecar_kzg_proofs*(sidecar: DataColumnSidecar): Result[void, string] =
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# Verifying if the KZG proofs are correct
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# Check if the data column sidecar index < NUMBER_OF_COLUMNS
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if not (sidecar.index < NUMBER_OF_COLUMNS):
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return err("EIP7594: Data column sidecar index exceeds the NUMBER_OF_COLUMNS")
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# Check is the sidecar column length == sidecar.kzg_commitments length == sidecar.kzg_proofs mixInLength
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if not (sidecar.column.len == sidecar.kzg_commitments.len):
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return err("EIP7594: Data column sidecar length is not equal to the kzg_commitments length")
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if not (sidecar.kzg_commitments.len == sidecar.kzg_proofs.len):
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return err("EIP7594: Data column sidecar kzg_commitments length is not equal to the kzg_proofs length")
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# Iterate through the cell indices
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var cellIndices: seq[CellIndex]
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for _ in 0..<sidecar.column.len:
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cellIndices.add(sidecar.index * sidecar.column.lenu64)
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let
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kzgCommits = sidecar.kzg_commitments.asSeq
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sidecarCol = sidecar.column.asSeq
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kzgProofs = sidecar.kzg_proofs.asSeq
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let res = verifyCellKzgProofBatch(kzgCommits, cellIndices, sidecarCol, kzgProofs)
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if res.isErr():
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return err("DataColumnSidecar: validation failed")
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ok()
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# https://github.com/ethereum/consensus-specs/blob/5f48840f4d768bf0e0a8156a3ed06ec333589007/specs/_features/eip7594/p2p-interface.md#verify_data_column_sidecar_inclusion_proof
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func verify_data_column_sidecar_inclusion_proof*(sidecar: DataColumnSidecar): Result[void, string] =
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# Verify if the given KZG commitments are included in the beacon block
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let gindex = 27.GeneralizedIndex
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if not is_valid_merkle_branch(
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hash_tree_root(sidecar.kzg_commitments),
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sidecar.kzg_commitments_inclusion_proof,
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4.int,
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get_subtree_index(gindex),
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sidecar.signed_block_header.message.body_root):
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return err("DataColumnSidecar: inclusion proof not valid")
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ok()
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proc selfReconstructDataColumns*(numCol: uint64):
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bool =
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# This function tells whether data columns can be
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# reconstructed or not
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const totalColumns = NUMBER_OF_COLUMNS.uint64
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let
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columnsNeeded = totalColumns div 2 + totalColumns mod 2
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if numCol >= columnsNeeded:
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return true
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false
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# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.3/specs/_features/eip7594/das-core.md#compute_extended_matrix
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proc get_extended_sample_count*(samples_per_slot: int,
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allowed_failures: int):
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int =
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# `get_extended_sample_count` computes the number of samples we
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# should query from peers, given the SAMPLES_PER_SLOT and
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# the number of allowed failures
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# Retrieving the column count
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let columnsCount = NUMBER_OF_COLUMNS.int
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# If 50% of the columns are missing, we are able to reconstruct the data
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# If 50% + 1 columns are missing, we are NO MORE able to reconstruct the data
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let worstCaseConditionCount = (columnsCount div 2) + 1
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# Compute the false positive threshold
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let falsePositiveThreshold = hypergeom_cdf(0, columnsCount, worstCaseConditionCount, samples_per_slot)
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var sampleCount: int
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# Finally, compute the extended sample count
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for i in samples_per_slot .. columnsCount + 1:
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if hypergeom_cdf(allowed_failures, columnsCount, worstCaseConditionCount, i) <= falsePositiveThreshold:
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sampleCount = i
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break
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sampleCount = i
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return sampleCount
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