422 lines
16 KiB
Nim
422 lines
16 KiB
Nim
# Nimbus
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# Copyright (c) 2018 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed except
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# according to those terms.
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##
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## Verify Headers for Clique PoA Consensus Protocol
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## ================================================
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##
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## Note that mining in currently unsupported by `NIMBUS`
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##
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## For details see
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## `EIP-225 <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-225.md>`_
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## and
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## `go-ethereum <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-225.md>`_
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##
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import
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std/[strformat, times, sequtils],
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../../utils/utils,
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../../common/common,
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../gaslimit,
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./clique_cfg,
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./clique_defs,
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./clique_desc,
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./clique_helpers,
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./clique_snapshot,
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./snapshot/[ballot, snapshot_desc],
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chronicles,
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stew/results
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{.push raises: [].}
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logScope:
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topics = "clique PoA verify header"
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# ------------------------------------------------------------------------------
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# Private helpers
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# ------------------------------------------------------------------------------
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# consensus/misc/forks.go(30): func VerifyForkHashes(config [..]
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proc verifyForkHashes(com: CommonRef; header: BlockHeader): CliqueOkResult
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{.gcsafe, raises: [ValueError].} =
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## Verify that blocks conforming to network hard-forks do have the correct
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## hashes, to avoid clients going off on different chains.
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if com.eip150Block.isSome and
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com.eip150Block.get == header.blockNumber:
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# If the homestead reprice hash is set, validate it
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let
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eip150 = com.eip150Hash
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hash = header.blockHash
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if eip150 != hash:
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return err((errCliqueGasRepriceFork,
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&"Homestead gas reprice fork: have {eip150}, want {hash}"))
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return ok()
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proc signersThreshold*(s: Snapshot): int =
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## Minimum number of authorised signers needed.
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s.ballot.authSignersThreshold
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proc recentBlockNumber*(s: Snapshot; a: EthAddress): Result[BlockNumber,void] =
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## Return `BlockNumber` for `address` argument (if any)
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for (number,recent) in s.recents.pairs:
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if recent == a:
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return ok(number)
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return err()
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proc isSigner*(s: Snapshot; address: EthAddress): bool =
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## Checks whether argukment ``address` is in signers list
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s.ballot.isAuthSigner(address)
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# clique/snapshot.go(319): func (s *Snapshot) inturn(number [..]
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proc inTurn*(s: Snapshot; number: BlockNumber, signer: EthAddress): bool =
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## Returns `true` if a signer at a given block height is in-turn.
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let ascSignersList = s.ballot.authSigners
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if 0 < ascSignersList.len:
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let offset = (number mod ascSignersList.len.u256).truncate(int64)
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return ascSignersList[offset] == signer
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# ------------------------------------------------------------------------------
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# Private functions
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# ------------------------------------------------------------------------------
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# clique/clique.go(463): func (c *Clique) verifySeal(chain [..]
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proc verifySeal(c: Clique; header: BlockHeader): CliqueOkResult =
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## Check whether the signature contained in the header satisfies the
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## consensus protocol requirements. The method accepts an optional list of
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## parent headers that aren't yet part of the local blockchain to generate
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## the snapshots from.
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# Verifying the genesis block is not supported
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if header.blockNumber.isZero:
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return err((errUnknownBlock,""))
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# Get current snapshot
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let snapshot = c.snapshot
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# Verify availability of the cached snapshot
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doAssert snapshot.blockHash == header.parentHash
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# Resolve the authorization key and check against signers
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let signer = c.cfg.ecRecover(header)
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if signer.isErr:
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return err((errEcRecover,$signer.error))
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if not snapshot.isSigner(signer.value):
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return err((errUnauthorizedSigner,""))
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let seen = snapshot.recentBlockNumber(signer.value)
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if seen.isOk:
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# Signer is among recents, only fail if the current block does not
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# shift it out
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# clique/clique.go(486): if limit := uint64(len(snap.Signers)/2 + 1); [..]
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if header.blockNumber - snapshot.signersThreshold.u256 < seen.value:
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return err((errRecentlySigned,""))
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# Ensure that the difficulty corresponds to the turn-ness of the signer
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if snapshot.inTurn(header.blockNumber, signer.value):
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if header.difficulty != DIFF_INTURN:
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return err((errWrongDifficulty,"INTURN expected"))
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else:
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if header.difficulty != DIFF_NOTURN:
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return err((errWrongDifficulty,"NOTURN expected"))
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ok()
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# clique/clique.go(314): func (c *Clique) verifyCascadingFields(chain [..]
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proc verifyCascadingFields(c: Clique; com: CommonRef; header: BlockHeader;
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parents: var seq[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [CatchableError].} =
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## Verify all the header fields that are not standalone, rather depend on a
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## batch of previous headers. The caller may optionally pass in a batch of
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## parents (ascending order) to avoid looking those up from the database.
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## This is useful for concurrently verifying a batch of new headers.
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# The genesis block is the always valid dead-end
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if header.blockNumber.isZero:
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return ok()
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# Ensure that the block's timestamp isn't too close to its parent
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var parent: BlockHeader
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if 0 < parents.len:
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parent = parents[^1]
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elif not c.db.getBlockHeader(header.blockNumber-1, parent):
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return err((errUnknownAncestor,""))
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if parent.blockNumber != header.blockNumber-1 or
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parent.blockHash != header.parentHash:
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return err((errUnknownAncestor,""))
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# clique/clique.go(330): if parent.Time+c.config.Period > header.Time {
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if header.timestamp < parent.timestamp + c.cfg.period:
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return err((errInvalidTimestamp,""))
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# Verify that the gasUsed is <= gasLimit
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block:
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# clique/clique.go(333): if header.GasUsed > header.GasLimit {
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let (used, limit) = (header.gasUsed, header.gasLimit)
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if limit < used:
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return err((errCliqueExceedsGasLimit,
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&"invalid gasUsed: have {used}, gasLimit {limit}"))
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# Verify `GasLimit` or `BaseFee` depending on whether before or after
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# EIP-1559/London fork.
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block:
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# clique/clique.go(337): if !chain.Config().IsLondon(header.Number) {
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let rc = com.validateGasLimitOrBaseFee(header, parent)
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if rc.isErr:
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return err((errCliqueGasLimitOrBaseFee, rc.error))
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# Retrieve the snapshot needed to verify this header and cache it
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block:
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# clique/clique.go(350): snap, err := c.snapshot(chain, number-1, ..
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let rc = c.cliqueSnapshotSeq(header.parentHash, parents)
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if rc.isErr:
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return err(rc.error)
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# If the block is a checkpoint block, verify the signer list
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if (header.blockNumber mod c.cfg.epoch.u256) == 0:
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var addrList = header.extraData.extraDataAddresses
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# not using `authSigners()` here as it is too slow
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if c.snapshot.ballot.authSignersLen != addrList.len or
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not c.snapshot.ballot.isAuthSigner(addrList):
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return err((errMismatchingCheckpointSigners,""))
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# All basic checks passed, verify the seal and return
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return c.verifySeal(header)
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proc verifyHeaderFields(c: Clique; header: BlockHeader): CliqueOkResult =
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## Check header fields, the ones that do not depend on a parent block.
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# clique/clique.go(250): number := header.Number.Uint64()
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# Don't waste time checking blocks from the future
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if getTime() < header.timestamp:
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return err((errFutureBlock,""))
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# Checkpoint blocks need to enforce zero beneficiary
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let isCheckPoint = (header.blockNumber mod c.cfg.epoch.u256) == 0
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if isCheckPoint and not header.coinbase.isZero:
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return err((errInvalidCheckpointBeneficiary,""))
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# Nonces must be 0x00..0 or 0xff..f, zeroes enforced on checkpoints
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if header.nonce != NONCE_AUTH and header.nonce != NONCE_DROP:
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return err((errInvalidVote,""))
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if isCheckPoint and header.nonce != NONCE_DROP:
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return err((errInvalidCheckpointVote,""))
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# Check that the extra-data contains both the vanity and signature
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if header.extraData.len < EXTRA_VANITY:
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return err((errMissingVanity,""))
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if header.extraData.len < EXTRA_VANITY + EXTRA_SEAL:
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return err((errMissingSignature,""))
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# Ensure that the extra-data contains a signer list on a checkpoint,
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# but none otherwise
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let signersBytes = header.extraData.len - EXTRA_VANITY - EXTRA_SEAL
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if not isCheckPoint:
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if signersBytes != 0:
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return err((errExtraSigners,""))
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elif (signersBytes mod EthAddress.len) != 0:
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return err((errInvalidCheckpointSigners,""))
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# Ensure that the mix digest is zero as we do not have fork protection
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# currently
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if not header.mixDigest.isZero:
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return err((errInvalidMixDigest,""))
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# Ensure that the block does not contain any uncles which are meaningless
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# in PoA
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if header.ommersHash != EMPTY_UNCLE_HASH:
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return err((errInvalidUncleHash,""))
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# Ensure that the block's difficulty is meaningful (may not be correct at
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# this point)
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if not header.blockNumber.isZero:
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# Note that neither INTURN or NOTURN should be zero (but this might be
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# subject to change as it is explicitely checked for in `clique.go`)
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let diffy = header.difficulty
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# clique/clique.go(246): if header.Difficulty == nil || (header.Difficulty..
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if diffy.isZero or (diffy != DIFF_INTURN and diffy != DIFF_NOTURN):
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return err((errInvalidDifficulty,""))
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# verify that the gas limit is <= 2^63-1
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when header.gasLimit.typeof isnot int64:
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if int64.high < header.gasLimit:
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return err((errCliqueExceedsGasLimit,
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&"invalid gasLimit: have {header.gasLimit}, must be int64"))
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ok()
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# clique/clique.go(246): func (c *Clique) verifyHeader(chain [..]
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proc cliqueVerifyImpl(c: Clique; com: CommonRef; header: BlockHeader;
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parents: var seq[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [CatchableError].} =
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## Check whether a header conforms to the consensus rules. The caller may
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## optionally pass in a batch of parents (ascending order) to avoid looking
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## those up from the database. This is useful for concurrently verifying
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## a batch of new headers.
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c.failed = (ZERO_HASH256,cliqueNoError)
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block:
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# Check header fields independent of parent blocks
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let rc = c.verifyHeaderFields(header)
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if rc.isErr:
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c.failed = (header.blockHash, rc.error)
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return err(rc.error)
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block:
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# If all checks passed, validate any special fields for hard forks
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let rc = com.verifyForkHashes(header)
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if rc.isErr:
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c.failed = (header.blockHash, rc.error)
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return err(rc.error)
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# All basic checks passed, verify cascading fields
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result = c.verifyCascadingFields(com, header, parents)
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if result.isErr:
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c.failed = (header.blockHash, result.error)
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proc cliqueVerifySeq*(c: Clique; com: CommonRef; header: BlockHeader;
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parents: var seq[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [CatchableError].} =
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## Check whether a header conforms to the consensus rules. The caller may
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## optionally pass in a batch of parents (ascending order) to avoid looking
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## those up from the database. This is useful for concurrently verifying
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## a batch of new headers.
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##
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## On success, the latest authorised signers list is available via the
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## fucntion `c.cliqueSigners()`. Otherwise, the latest error is also stored
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## in the `Clique` descriptor
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##
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## If there is an error, this error is also stored within the `Clique`
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## descriptor and can be retrieved via `c.failed` along with the hash/ID of
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## the failed block header.
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block:
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let rc = c.cliqueVerifyImpl(com, header, parents)
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if rc.isErr:
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return rc
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# Adjust current shapshot (the function `cliqueVerifyImpl()` typically
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# works with the parent snapshot.
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block:
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let rc = c.cliqueSnapshotSeq(header, parents)
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if rc.isErr:
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return err(rc.error)
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ok()
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proc cliqueVerifySeq(c: Clique; com: CommonRef;
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headers: var seq[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [CatchableError].} =
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## This function verifies a batch of headers checking each header for
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## consensus rules conformance. The `headers` list is supposed to
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## contain a chain of headers, i e. `headers[i]` is parent to `headers[i+1]`.
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##
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## On success, the latest authorised signers list is available via the
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## fucntion `c.cliqueSigners()`. Otherwise, the latest error is also stored
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## in the `Clique` descriptor
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##
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## If there is an error, this error is also stored within the `Clique`
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## descriptor and can be retrieved via `c.failed` along with the hash/ID of
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## the failed block header.
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##
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## Note that the sequence argument must be write-accessible, even though it
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## will be left untouched by this function.
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if 0 < headers.len:
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headers.shallow
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block:
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var blind: seq[BlockHeader]
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let rc = c.cliqueVerifyImpl(com, headers[0],blind)
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if rc.isErr:
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return rc
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for n in 1 ..< headers.len:
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var parent = headers[n-1 .. n-1] # is actually a single item squence
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let rc = c.cliqueVerifyImpl(com, headers[n],parent)
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if rc.isErr:
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return rc
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# Adjust current shapshot (the function `cliqueVerifyImpl()` typically
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# works with the parent snapshot.
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block:
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let rc = c.cliqueSnapshot(headers[^1])
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if rc.isErr:
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return err(rc.error)
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ok()
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc cliqueVerify*(c: Clique; com: CommonRef; header: BlockHeader;
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parents: openArray[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [CatchableError].} =
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## Check whether a header conforms to the consensus rules. The caller may
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## optionally pass on a batch of parents (ascending order) to avoid looking
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## those up from the database. This function updates the list of authorised
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## signers (see `cliqueSigners()` below.)
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##
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## On success, the latest authorised signers list is available via the
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## fucntion `c.cliqueSigners()`. Otherwise, the latest error is also stored
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## in the `Clique` descriptor and is accessible as `c.failed`.
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##
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## This function is not transaction-save, that is the internal state of
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## the authorised signers list has the state of the last update after a
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## successful header verification. The hash of the failing header together
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## with the error message is then accessible as `c.failed`.
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##
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## Use the directives `cliqueSave()`, `cliqueDispose()`, and/or
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## `cliqueRestore()` for transaction.
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var list = toSeq(parents)
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c.cliqueVerifySeq(com, header, list)
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# clique/clique.go(217): func (c *Clique) VerifyHeader(chain [..]
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proc cliqueVerify*(c: Clique; com: CommonRef; header: BlockHeader): CliqueOkResult
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{.gcsafe, raises: [CatchableError].} =
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## Consensus rules verifier without optional parents list.
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var blind: seq[BlockHeader]
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c.cliqueVerifySeq(com, header, blind)
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proc cliqueVerify*(c: Clique; com: CommonRef;
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headers: openArray[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [CatchableError].} =
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## This function verifies a batch of headers checking each header for
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## consensus rules conformance (see also the other `cliqueVerify()` function
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## instance.) The `headers` list is supposed to contain a chain of headers,
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## i.e. `headers[i]` is parent to `headers[i+1]`.
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##
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## On success, the latest authorised signers list is available via the
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## fucntion `c.cliqueSigners()`. Otherwise, the latest error is also stored
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## in the `Clique` descriptor and is accessible as `c.failed`.
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##
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## This function is not transaction-save, that is the internal state of
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## the authorised signers list has the state of the last update after a
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## successful header verification. The hash of the failing header together
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## with the error message is then accessible as `c.failed`.
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##
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## Use the directives `cliqueSave()`, `cliqueDispose()`, and/or
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## `cliqueRestore()` for transaction.
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var list = toSeq(headers)
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c.cliqueVerifySeq(com, list)
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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