156 lines
6.2 KiB
Nim
156 lines
6.2 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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## EIP-225 Clique PoA Consensus Protocol
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## =====================================
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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/[sequtils, times],
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../db/db_chain,
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./clique/[clique_cfg, clique_defs, clique_desc, clique_verify],
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./clique/snapshot/[ballot, snapshot_desc],
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eth/common,
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stew/results
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{.push raises: [Defect].}
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# Note that mining is unsupported. Unused code ported from the Go
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# implementation is stashed into the `clique_unused` module.
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export
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clique_cfg,
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clique_defs,
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clique_desc.Clique
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type
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CliqueState* = ##\
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## Descriptor state snapshot which can be used for implementing
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## transaction trasnaction handling. Nore the the `Snapshot` type
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## inside the `Result[]` is most probably opaque.
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Result[Snapshot,void]
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# ------------------------------------------------------------------------------
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# Public
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# ------------------------------------------------------------------------------
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proc newClique*(db: BaseChainDB): Clique =
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## Constructor for a new Clique proof-of-authority consensus engine. The
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## initial state of the engine is `empty`, there are no authorised signers.
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##
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## If chain_config provides `Period` or `Epoch`, then `Period` or `Epoch`
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## will be taken from chain_config. Otherwise, default value in `newCliqueCfg`
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## will be used
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let cfg = db.newCliqueCfg
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if db.config.cliquePeriod > 0:
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cfg.period = initDuration(seconds = db.config.cliquePeriod)
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if db.config.cliqueEpoch > 0:
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cfg.epoch = db.config.cliqueEpoch
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cfg.newClique
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proc cliqueSave*(c: var Clique): CliqueState =
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## Save current `Clique` state. This state snapshot saves the internal
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## data that make up the list of authorised signers (see `cliqueSigners()`
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## below.)
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ok(c.snapshot)
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proc cliqueRestore*(c: var Clique; state: var CliqueState) =
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## Restore current `Clique` state from a saved snapshot.
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##
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## For the particular `state` argument this fuction is disabled with
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## `cliqueDispose()`. So it can be savely wrapped in a `defer:` statement.
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## In transaction lingo, this would then be the rollback function.
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if state.isOk:
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c.snapshot = state.value
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proc cliqueDispose*(c: var Clique; state: var CliqueState) =
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## Disable the function `cliqueDispose()` for the particular `state`
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## argument.
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##
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## In transaction lingo, this would be the commit function if
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## `cliqueRestore()` was wrapped in a `defer:` statement.
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state = err(CliqueState)
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proc cliqueVerify*(c: Clique; header: BlockHeader;
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parents: openArray[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [Defect,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(header, list)
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# clique/clique.go(217): func (c *Clique) VerifyHeader(chain [..]
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proc cliqueVerify*(c: Clique; header: BlockHeader): CliqueOkResult
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{.gcsafe, raises: [Defect,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(header, blind)
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proc cliqueVerify*(c: Clique;
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headers: openArray[BlockHeader]): CliqueOkResult
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{.gcsafe, raises: [Defect,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(list)
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proc cliqueSigners*(c: Clique): seq[EthAddress] {.inline.} =
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## Retrieve the sorted list of authorized signers for the current state
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## of the `Clique` descriptor.
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##
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## Note that the return argument list is sorted on-the-fly each time this
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## function is invoked.
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c.snapshot.ballot.authSigners
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proc cliqueSignersLen*(c: Clique): int {.inline.} =
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## Get the number of authorized signers for the current state of the
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## `Clique` descriptor. The result is equivalent to `c.cliqueSigners.len`.
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c.snapshot.ballot.authSignersLen
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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