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nimbus-eth1/nimbus/core/clique/clique_sealer.nim

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# Nimbus
# Copyright (c) 2018 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.
##
## Mining Support for Clique PoA Consensus Protocol
## ===================!=============================
##
## For details see
## `EIP-225 <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-225.md>`_
## and
## `go-ethereum <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-225.md>`_
##
import
std/[sequtils, times],
chronicles,
chronos,
eth/keys,
"../.."/[constants, utils/ec_recover],
../../common/common,
./clique_cfg,
./clique_defs,
./clique_desc,
./clique_helpers,
./clique_snapshot,
./clique_verify,
./snapshot/[ballot, snapshot_desc]
{.push raises: [Defect].}
logScope:
topics = "clique PoA Mining"
# ------------------------------------------------------------------------------
# Private Helpers
# ------------------------------------------------------------------------------
proc isValidVote(s: Snapshot; a: EthAddress; authorize: bool): bool {.gcsafe, raises: [].} =
s.ballot.isValidVote(a, authorize)
proc isSigner*(s: Snapshot; address: EthAddress): bool {.gcsafe, raises: [].} =
## See `clique_verify.isSigner()`
s.ballot.isAuthSigner(address)
# clique/snapshot.go(319): func (s *Snapshot) inturn(number [..]
proc inTurn*(s: Snapshot; number: BlockNumber, signer: EthAddress): bool {.gcsafe, raises: [].} =
## See `clique_verify.inTurn()`
let ascSignersList = s.ballot.authSigners
for offset in 0 ..< ascSignersList.len:
if ascSignersList[offset] == signer:
return (number mod ascSignersList.len.u256) == offset.u256
# ------------------------------------------------------------------------------
# Private functions
# ------------------------------------------------------------------------------
# clique/clique.go(681): func calcDifficulty(snap [..]
proc calcDifficulty(s: Snapshot; signer: EthAddress): DifficultyInt {.gcsafe, raises: [].} =
if s.inTurn(s.blockNumber + 1, signer):
DIFF_INTURN
else:
DIFF_NOTURN
proc recentBlockNumber*(s: Snapshot;
a: EthAddress): Result[BlockNumber,void] {.gcsafe, raises: [].} =
## Return `BlockNumber` for `address` argument (if any)
for (number,recent) in s.recents.pairs:
if recent == a:
return ok(number)
return err()
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
# clique/clique.go(506): func (c *Clique) Prepare(chain [..]
proc prepare*(c: Clique; parent: BlockHeader, header: var BlockHeader): CliqueOkResult
{.gcsafe, raises: [CatchableError].} =
## For the Consensus Engine, `prepare()` initializes the consensus fields
## of a block header according to the rules of a particular engine.
##
## This implementation prepares all the consensus fields of the header for
## running the transactions on top.
# Assemble the voting snapshot to check which votes make sense
let rc = c.cliqueSnapshot(parent.blockHash, @[])
if rc.isErr:
return err(rc.error)
# if we are not voting, coinbase should be filled with zero
# because other subsystem e.g txpool can produce block header
# with non zero coinbase. if that coinbase is one of the signer
# and the nonce is zero, that signer will be vote out from
# signer list
header.coinbase.reset
let modEpoch = (parent.blockNumber+1) mod c.cfg.epoch
if modEpoch != 0:
# Gather all the proposals that make sense voting on
var addresses: seq[EthAddress]
for (address,authorize) in c.proposals.pairs:
if c.snapshot.isValidVote(address, authorize):
addresses.add address
# If there's pending proposals, cast a vote on them
if 0 < addresses.len:
header.coinbase = addresses[c.cfg.rand(addresses.len-1)]
header.nonce = if header.coinbase in c.proposals: NONCE_AUTH
else: NONCE_DROP
# Set the correct difficulty
header.difficulty = c.snapshot.calcDifficulty(c.signer)
# Ensure the extra data has all its components
header.extraData.setLen(EXTRA_VANITY)
if modEpoch == 0:
header.extraData.add c.snapshot.ballot.authSigners.mapIt(toSeq(it)).concat
header.extraData.add 0.byte.repeat(EXTRA_SEAL)
# Mix digest is reserved for now, set to empty
header.mixDigest.reset
# Ensure the timestamp has the correct delay
header.timestamp = parent.timestamp + c.cfg.period
if header.timestamp < getTime():
header.timestamp = getTime()
ok()
proc prepareForSeal*(c: Clique; prepHeader: BlockHeader; header: var BlockHeader) {.gcsafe, raises: [].} =
# TODO: use system.move?
header.nonce = prepHeader.nonce
header.extraData = prepHeader.extraData
header.mixDigest = prepHeader.mixDigest
# clique/clique.go(589): func (c *Clique) Authorize(signer [..]
proc authorize*(c: Clique; signer: EthAddress; signFn: CliqueSignerFn) {.gcsafe, raises: [].} =
## Injects private key into the consensus engine to mint new blocks with.
c.signer = signer
c.signFn = signFn
# clique/clique.go(724): func CliqueRLP(header [..]
proc cliqueRlp*(header: BlockHeader): seq[byte] {.gcsafe, raises: [].} =
## Returns the rlp bytes which needs to be signed for the proof-of-authority
## sealing. The RLP to sign consists of the entire header apart from the 65
## byte signature contained at the end of the extra data.
##
## Note, the method requires the extra data to be at least 65 bytes,
## otherwise it panics. This is done to avoid accidentally using both forms
## (signature present or not), which could be abused to produce different
##hashes for the same header.
header.encodeSealHeader
# clique/clique.go(688): func SealHash(header *types.Header) common.Hash {
proc sealHash*(header: BlockHeader): Hash256 {.gcsafe, raises: [].} =
## For the Consensus Engine, `sealHash()` returns the hash of a block prior
## to it being sealed.
##
## This implementation returns the hash of a block prior to it being sealed.
header.hashSealHeader
# clique/clique.go(599): func (c *Clique) Seal(chain [..]
proc seal*(c: Clique; ethBlock: var EthBlock):
Result[void,CliqueError] {.gcsafe,
raises: [CatchableError].} =
## This implementation attempts to create a sealed block using the local
## signing credentials.
var header = ethBlock.header
# Sealing the genesis block is not supported
if header.blockNumber.isZero:
return err((errUnknownBlock, ""))
# For 0-period chains, refuse to seal empty blocks (no reward but would spin
# sealing)
if c.cfg.period.isZero and ethBlock.txs.len == 0:
info $nilCliqueSealNoBlockYet
return err((nilCliqueSealNoBlockYet, ""))
# Don't hold the signer fields for the entire sealing procedure
let
signer = c.signer
signFn = c.signFn
# Bail out if we're unauthorized to sign a block
let rc = c.cliqueSnapshot(header.parentHash)
if rc.isErr:
return err(rc.error)
if not c.snapshot.isSigner(signer):
return err((errUnauthorizedSigner, ""))
# If we're amongst the recent signers, wait for the next block
let seen = c.snapshot.recentBlockNumber(signer)
if seen.isOk:
# Signer is among recents, only wait if the current block does not
# shift it out
if header.blockNumber < seen.value + c.snapshot.signersThreshold.u256:
info $nilCliqueSealSignedRecently
return err((nilCliqueSealSignedRecently, ""))
# Sweet, the protocol permits us to sign the block, wait for our time
var delay = header.timestamp - getTime()
if header.difficulty == DIFF_NOTURN:
# It's not our turn explicitly to sign, delay it a bit
let wiggle = c.snapshot.signersThreshold.int64 * WIGGLE_TIME
# Kludge for limited rand() argument range
if wiggle.inSeconds < (int.high div 1000).int64:
let rndWiggleMs = c.cfg.rand(wiggle.inMilliseconds.int)
delay += initDuration(milliseconds = rndWiggleMs)
else:
let rndWiggleSec = c.cfg.rand((wiggle.inSeconds and int.high).int)
delay += initDuration(seconds = rndWiggleSec)
trace "Out-of-turn signing requested",
wiggle = $wiggle
# Sign all the things!
try:
let signature = signFn(signer,header.cliqueRlp)
if signature.isErr:
return err((errCliqueSealSigFn,$signature.error))
let extraLen = header.extraData.len
if EXTRA_SEAL < extraLen:
header.extraData.setLen(extraLen - EXTRA_SEAL)
header.extraData.add signature.value
except Exception as exc:
return err((errCliqueSealSigFn,
"Error when signing block header: " & exc.msg))
ethBlock = ethBlock.withHeader(header)
ok()
# clique/clique.go(673): func (c *Clique) CalcDifficulty(chain [..]
proc calcDifficulty*(c: Clique;
parent: BlockHeader): Result[DifficultyInt,CliqueError]
{.gcsafe, raises: [CatchableError].} =
## For the Consensus Engine, `calcDifficulty()` is the difficulty adjustment
## algorithm. It returns the difficulty that a new block should have.
##
## This implementation returns the difficulty that a new block should have:
## * DIFF_NOTURN(2) if BLOCK_NUMBER % SIGNER_COUNT != SIGNER_INDEX
## * DIFF_INTURN(1) if BLOCK_NUMBER % SIGNER_COUNT == SIGNER_INDEX
let rc = c.cliqueSnapshot(parent)
if rc.isErr:
return err(rc.error)
return ok(c.snapshot.calcDifficulty(c.signer))
# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------
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