WIP outline of the Blockchain sync procedure using the ETH wire protocol
This commit is contained in:
Zahary Karadjov
parent
4d17ab1ee5
commit
96cf717778
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@ -12,8 +12,6 @@ import
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rlp/types, stint, rlpx, eth_common
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type
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P = UInt256
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NewBlockHashesAnnounce* = object
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hash: KeccakHash
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number: uint
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@ -22,34 +20,76 @@ type
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header: BlockHeader
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body {.rlpInline.}: BlockBody
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NetworkState = object
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syncing: bool
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PeerState = object
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reportedTotalDifficulty: Difficulty
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latestBlockHash: KeccakHash
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const
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maxStateFetch = 384
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maxBodiesFetch = 128
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maxReceiptsFetch = 256
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maxHeadersFetch = 192
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rlpxProtocol eth, 63:
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useRequestIds = false
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proc status(p: Peer, protocolVersion, networkId, td: P,
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proc status(peer: Peer,
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protocolVersion, networkId: uint,
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totalDifficulty: Difficulty,
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bestHash, genesisHash: KeccakHash) =
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discard
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# verify that the peer is on the same chain:
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if peer.network.id != networkId or
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peer.network.chain.genesisHash != genesisHash:
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peer.disconnect()
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return
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proc newBlockHashes(p: Peer, hashes: openarray[NewBlockHashesAnnounce]) =
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p.state.reportedTotalDifficulty = totalDifficulty
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proc newBlockHashes(peer: Peer, hashes: openarray[NewBlockHashesAnnounce]) =
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discard
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proc transactions(p: Peer, transactions: openarray[Transaction]) =
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discard
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requestResponse:
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proc getBlockHeaders(p: Peer, hash: BlocksRequest) =
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discard
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proc getBlockHeaders(peer: Peer, request: BlocksRequest) =
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if request.maxResults > maxHeadersFetch:
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peer.disconnect()
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return
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proc blockHeaders(p: Peer, hashes: openarray[BlockHeader]) =
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discard
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var foundBlock = peer.network.chain.locateBlock(startBlock)
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if not foundBlock.isNil:
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var headers = newSeqOfCap[BlockHeader](request.maxResults)
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while headers.len < request.maxResults:
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headers.add peer.network.chain.getBlockHeader(foundBlock)
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foundBlock = foundBlock.nextBlock()
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if foundBlock.isNil: break
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discard await peer.blockHeaders(headers)
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proc blockHeaders(p: Peer, headers: openarray[BlockHeader])
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requestResponse:
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proc getBlockBodies(p: Peer, hashes: openarray[KeccakHash]) =
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discard
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if hashes.len > maxBodiesFetch:
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peer.disconnect()
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return
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proc blockBodies(p: Peer, blocks: openarray[BlockBody]) =
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discard
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var blockBodies = newSeqOfCap[BlockBody](hashes.len)
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for hash in hashes:
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let blockBody = peer.network.chain.getBlockBody(hash)
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if not blockBody.isNil:
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blockBodies.add deref(blockBody)
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proc newBlock(p: Peer, bh: NewBlockAnnounce, totalDificulty: P) =
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discard await peer.blockBodies(blockBodies)
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proc blockBodies(p: Peer, blocks: openarray[BlockBody])
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proc newBlock(p: Peer, bh: NewBlockAnnounce, totalDifficulty: Difficulty) =
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discard
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nextID 13
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@ -68,3 +108,40 @@ rlpxProtocol eth, 63:
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proc receipts(p: Peer, receipts: openarray[Receipt]) =
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discard
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proc fastBlockchainSync*(network: EthereumNode) {.async.} =
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# 1. obtain last N block headers from all peers
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var latestBlocksRequest: BlocksRequest
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var requests = newSeqOfCap[Future[eth.blockHeaders]](32)
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for peer in network.peerPool:
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if peer.supports(eth):
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requests.add peer.getBlockHeaders(latestBlocksRequest)
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await all(requests)
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# 2. find out what is the block with best total difficulty
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var bestBlockDifficulty: Difficulty = 0
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for req in requests:
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if req.read.isNone: continue
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for header in req.read.get.headers:
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if header.difficulty > bestBlockDifficulty:
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discard
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# 3. establish the highest valid block for each peer
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# keep in mind that some of the peers may report an alternative history, so
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# we must find the last block where each peer agreed with the best peer
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# 4. Start making requests in parallel for the block headers that we are
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# missing (by requesting blocks from peers while honoring maxHeadersFetch).
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# Make sure the blocks hashes add up. Don't count on everyone replying, ask
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# a different peer in case of time-out. Handle invalid or incomplete replies
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# properly. The peer may response with fewer headers than requested (or with
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# different ones if the peer is not behaving properly).
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# 5. Store the obtained headers in the blockchain DB
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# 6. Once the sync is complete, repeat from 1. until to further progress is
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# possible
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# 7. Start downloading the blockchain state in parallel
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# (maybe this could start earlier).
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@ -9,7 +9,7 @@
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#
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import
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rlp/types, rlpx, eth_common
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rlp/types, rlpx, eth_common, times
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type
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ProofRequest* = object
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@ -40,8 +40,79 @@ type
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status*: TransactionStatus
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data*: Blob
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PeerState = object
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buffer: int
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lastRequestTime: float
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reportedTotalDifficulty: Difficulty
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KeyValuePair = object
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key: string
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value: Rlp
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const
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maxHeadersFetch = 192
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maxBodiesFetch = 32
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maxReceiptsFetch = 128
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maxCodeFetch = 64
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maxProofsFetch = 64
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maxHeaderProofsFetch = 64
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# Handshake properties:
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# https://github.com/zsfelfoldi/go-ethereum/wiki/Light-Ethereum-Subprotocol-(LES)
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const
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keyProtocolVersion = "protocolVersion"
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## P: is 1 for the LPV1 protocol version.
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keyNetworkId = "networkId"
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## P: should be 0 for testnet, 1 for mainnet.
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keyHeadTotalDifficulty = "headTd"
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## P: Total Difficulty of the best chain.
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## Integer, as found in block header.
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keyHeadHash = "headHash"
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## B_32: the hash of the best (i.e. highest TD) known block.
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keyHeadNumber = "headNum"
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## P: the number of the best (i.e. highest TD) known block.
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keyGenesisHash = "genesisHash"
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## B_32: the hash of the Genesis block.
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keyServeHeaders = "serveHeaders"
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## (optional, no value)
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## present if the peer can serve header chain downloads.
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keyServeChainSince = "serveChainSince"
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## P (optional)
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## present if the peer can serve Body/Receipts ODR requests
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## starting from the given block number.
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keyServeStateSince = "serveStateSince"
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## P (optional):
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## present if the peer can serve Proof/Code ODR requests
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## starting from the given block number.
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keyRelaysTransactions = "txRelay"
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## (optional, no value)
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## present if the peer can relay transactions to the ETH network.
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keyFlowControlBL = "flowControl/BL"
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keyFlowControlMRC = "flowControl/MRC"
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keyFlowControlMRR = "flowControl/MRR"
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## see Client Side Flow Control:
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## https://github.com/zsfelfoldi/go-ethereum/wiki/Client-Side-Flow-Control-model-for-the-LES-protocol
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const
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rechargeRate = 0.3
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proc getPeerWithNewestChain(pool: PeerPool): Peer =
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discard
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rlpxProtocol les, 2:
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type State = PeerState
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## Handshake
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##
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@ -52,8 +123,11 @@ rlpxProtocol les, 2:
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##
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proc announce(p: Peer, headHash: KeccakHash,
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headNumber, headTd, reorgDepth: P,
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values: openarray[KeyValuePair], announceType: uint) =
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headNumber: BlockNumber,
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headTotalDifficulty: Difficulty,
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reorgDepth: BlockNumber,
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values: openarray[KeyValuePair],
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announceType: uint) =
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discard
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requestResponse:
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