mirror of https://github.com/status-im/nim-eth.git
347 lines
12 KiB
Nim
347 lines
12 KiB
Nim
#
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# Ethereum P2P
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# (c) Copyright 2018
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# Status Research & Development GmbH
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#
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# Licensed under either of
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# Apache License, version 2.0, (LICENSE-APACHEv2)
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# MIT license (LICENSE-MIT)
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#
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import
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times,
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chronos, stint, nimcrypto, chronicles,
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eth/common/eth_types_json_serialization, eth/[keys, rlp],
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kademlia, enode
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export
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Node
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logScope:
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topics = "discovery"
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const
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# UDP packet constants.
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MAC_SIZE = 256 div 8 # 32
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SIG_SIZE = 520 div 8 # 65
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HEAD_SIZE = MAC_SIZE + SIG_SIZE # 97
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EXPIRATION = 60 # let messages expire after N secondes
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PROTO_VERSION = 4
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type
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DiscoveryProtocol* = ref object
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privKey: PrivateKey
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address: Address
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bootstrapNodes*: seq[Node]
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thisNode*: Node
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kademlia: KademliaProtocol[DiscoveryProtocol]
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transp: DatagramTransport
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CommandId = enum
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cmdPing = 1
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cmdPong = 2
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cmdFindNode = 3
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cmdNeighbours = 4
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DiscProtocolError* = object of CatchableError
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const MaxDgramSize = 1280
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const MinListLen: array[CommandId, int] = [4, 3, 2, 2]
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proc append*(w: var RlpWriter, a: IpAddress) =
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case a.family
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of IpAddressFamily.IPv6:
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w.append(a.address_v6.toMemRange)
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of IpAddressFamily.IPv4:
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w.append(a.address_v4.toMemRange)
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proc append(w: var RlpWriter, p: Port) {.inline.} = w.append(p.int)
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proc append(w: var RlpWriter, pk: PublicKey) {.inline.} = w.append(pk.getRaw())
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proc append(w: var RlpWriter, h: MDigest[256]) {.inline.} = w.append(h.data)
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proc pack(cmdId: CommandId, payload: BytesRange, pk: PrivateKey): Bytes =
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## Create and sign a UDP message to be sent to a remote node.
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##
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## See https://github.com/ethereum/devp2p/blob/master/rlpx.md#node-discovery for information on
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## how UDP packets are structured.
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# TODO: There is a lot of unneeded allocations here
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let encodedData = @[cmdId.byte] & payload.toSeq()
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let signature = @(pk.signMessage(encodedData).getRaw())
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let msgHash = keccak256.digest(signature & encodedData)
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result = @(msgHash.data) & signature & encodedData
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proc validateMsgHash(msg: Bytes, msgHash: var MDigest[256]): bool =
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if msg.len > HEAD_SIZE:
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msgHash.data[0 .. ^1] = msg.toOpenArray(0, msgHash.data.high)
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result = msgHash == keccak256.digest(msg.toOpenArray(MAC_SIZE, msg.high))
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proc recoverMsgPublicKey(msg: Bytes, pk: var PublicKey): bool =
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msg.len > HEAD_SIZE and
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recoverSignatureKey(msg.toOpenArray(MAC_SIZE, HEAD_SIZE),
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keccak256.digest(msg.toOpenArray(HEAD_SIZE, msg.high)).data,
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pk) == EthKeysStatus.Success
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proc unpack(msg: Bytes): tuple[cmdId: CommandId, payload: Bytes] =
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# Check against possible RangeError
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if msg[HEAD_SIZE].int < CommandId.low.ord or
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msg[HEAD_SIZE].int > CommandId.high.ord:
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raise newException(DiscProtocolError, "Unsupported packet id")
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result = (cmdId: msg[HEAD_SIZE].CommandId, payload: msg[HEAD_SIZE + 1 .. ^1])
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proc expiration(): uint32 =
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result = uint32(epochTime() + EXPIRATION)
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# Wire protocol
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proc send(d: DiscoveryProtocol, n: Node, data: seq[byte]) =
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let ta = initTAddress(n.node.address.ip, n.node.address.udpPort)
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let f = d.transp.sendTo(ta, data)
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f.callback = proc(data: pointer) {.gcsafe.} =
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if f.failed:
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debug "Discovery send failed", msg = f.readError.msg
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proc sendPing*(d: DiscoveryProtocol, n: Node): seq[byte] =
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let payload = rlp.encode((PROTO_VERSION, d.address, n.node.address,
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expiration())).toRange
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let msg = pack(cmdPing, payload, d.privKey)
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result = msg[0 ..< MAC_SIZE]
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trace ">>> ping ", n
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d.send(n, msg)
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proc sendPong*(d: DiscoveryProtocol, n: Node, token: MDigest[256]) =
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let payload = rlp.encode((n.node.address, token, expiration())).toRange
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let msg = pack(cmdPong, payload, d.privKey)
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trace ">>> pong ", n
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d.send(n, msg)
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proc sendFindNode*(d: DiscoveryProtocol, n: Node, targetNodeId: NodeId) =
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var data: array[64, byte]
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data[32 .. ^1] = targetNodeId.toByteArrayBE()
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let payload = rlp.encode((data, expiration())).toRange
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let msg = pack(cmdFindNode, payload, d.privKey)
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trace ">>> find_node to ", n#, ": ", msg.toHex()
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d.send(n, msg)
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proc sendNeighbours*(d: DiscoveryProtocol, node: Node, neighbours: seq[Node]) =
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const MAX_NEIGHBOURS_PER_PACKET = 12 # TODO: Implement a smarter way to compute it
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type Neighbour = tuple[ip: IpAddress, udpPort, tcpPort: Port, pk: PublicKey]
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var nodes = newSeqOfCap[Neighbour](MAX_NEIGHBOURS_PER_PACKET)
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shallow(nodes)
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template flush() =
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block:
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let payload = rlp.encode((nodes, expiration())).toRange
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let msg = pack(cmdNeighbours, payload, d.privkey)
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trace "Neighbours to", node, nodes
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d.send(node, msg)
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nodes.setLen(0)
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for i, n in neighbours:
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nodes.add((n.node.address.ip, n.node.address.udpPort,
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n.node.address.tcpPort, n.node.pubkey))
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if nodes.len == MAX_NEIGHBOURS_PER_PACKET:
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flush()
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if nodes.len != 0: flush()
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proc newDiscoveryProtocol*(privKey: PrivateKey, address: Address,
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bootstrapNodes: openarray[ENode]
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): DiscoveryProtocol =
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result.new()
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result.privKey = privKey
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result.address = address
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result.bootstrapNodes = newSeqOfCap[Node](bootstrapNodes.len)
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for n in bootstrapNodes: result.bootstrapNodes.add(newNode(n))
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result.thisNode = newNode(privKey.getPublicKey(), address)
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result.kademlia = newKademliaProtocol(result.thisNode, result)
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proc recvPing(d: DiscoveryProtocol, node: Node,
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msgHash: MDigest[256]) {.inline.} =
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d.kademlia.recvPing(node, msgHash)
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proc recvPong(d: DiscoveryProtocol, node: Node, payload: Bytes) {.inline.} =
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let rlp = rlpFromBytes(payload.toRange)
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let tok = rlp.listElem(1).toBytes().toSeq()
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d.kademlia.recvPong(node, tok)
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proc recvNeighbours(d: DiscoveryProtocol, node: Node,
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payload: Bytes) {.inline.} =
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let rlp = rlpFromBytes(payload.toRange)
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let neighboursList = rlp.listElem(0)
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let sz = neighboursList.listLen()
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var neighbours = newSeqOfCap[Node](16)
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for i in 0 ..< sz:
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let n = neighboursList.listElem(i)
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let ipBlob = n.listElem(0).toBytes
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var ip: IpAddress
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case ipBlob.len
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of 4:
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ip = IpAddress(family: IpAddressFamily.IPv4)
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copyMem(addr ip.address_v4[0], baseAddr ipBlob, 4)
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of 16:
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ip = IpAddress(family: IpAddressFamily.IPv6)
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copyMem(addr ip.address_v6[0], baseAddr ipBlob, 16)
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else:
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error "Wrong ip address length!"
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continue
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let udpPort = n.listElem(1).toInt(uint16).Port
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let tcpPort = n.listElem(2).toInt(uint16).Port
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var pk: PublicKey
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if recoverPublicKey(n.listElem(3).toBytes.toOpenArray(), pk) != EthKeysStatus.Success:
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warn "Could not parse public key"
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continue
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neighbours.add(newNode(pk, Address(ip: ip, udpPort: udpPort, tcpPort: tcpPort)))
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d.kademlia.recvNeighbours(node, neighbours)
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proc recvFindNode(d: DiscoveryProtocol, node: Node, payload: Bytes) {.inline, gcsafe.} =
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let rlp = rlpFromBytes(payload.toRange)
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trace "<<< find_node from ", node
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let rng = rlp.listElem(0).toBytes
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# Check for pubkey len
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if rng.len == 64:
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let nodeId = readUIntBE[256](rng[32 .. ^1].toOpenArray())
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d.kademlia.recvFindNode(node, nodeId)
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else:
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trace "Invalid target public key received"
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proc expirationValid(cmdId: CommandId, rlpEncodedPayload: seq[byte]):
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bool {.inline, raises:[DiscProtocolError, RlpError].} =
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## Can only raise `DiscProtocolError` and all of `RlpError`
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# Check if there is a payload
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if rlpEncodedPayload.len <= 0:
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raise newException(DiscProtocolError, "RLP stream is empty")
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let rlp = rlpFromBytes(rlpEncodedPayload.toRange)
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# Check payload is an RLP list and if the list has the minimum items required
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# for this packet type
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if rlp.isList and rlp.listLen >= MinListLen[cmdId]:
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# Expiration is always the last mandatory item of the list
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let expiration = rlp.listElem(MinListLen[cmdId] - 1).toInt(uint32)
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result = epochTime() <= expiration.float
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else:
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raise newException(DiscProtocolError, "Invalid RLP list for this packet id")
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proc receive*(d: DiscoveryProtocol, a: Address, msg: Bytes) {.gcsafe.} =
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## Can raise `DiscProtocolError` and all of `RlpError`
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# Note: export only needed for testing
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var msgHash: MDigest[256]
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if validateMsgHash(msg, msgHash):
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var remotePubkey: PublicKey
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if recoverMsgPublicKey(msg, remotePubkey):
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let (cmdId, payload) = unpack(msg)
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if expirationValid(cmdId, payload):
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let node = newNode(remotePubkey, a)
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case cmdId
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of cmdPing:
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d.recvPing(node, msgHash)
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of cmdPong:
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d.recvPong(node, payload)
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of cmdNeighbours:
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d.recvNeighbours(node, payload)
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of cmdFindNode:
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d.recvFindNode(node, payload)
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else:
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trace "Received msg already expired", cmdId, a
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else:
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error "Wrong public key from ", a
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else:
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error "Wrong msg mac from ", a
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proc processClient(transp: DatagramTransport,
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raddr: TransportAddress): Future[void] {.async, gcsafe.} =
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var proto = getUserData[DiscoveryProtocol](transp)
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var buf: seq[byte]
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try:
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# TODO: Maybe here better to use `peekMessage()` to avoid allocation,
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# but `Bytes` object is just a simple seq[byte], and `ByteRange` object
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# do not support custom length.
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var buf = transp.getMessage()
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let a = Address(ip: raddr.address, udpPort: raddr.port, tcpPort: raddr.port)
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proto.receive(a, buf)
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except RlpError as e:
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debug "Receive failed", exc = e.name, err = e.msg
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except DiscProtocolError as e:
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debug "Receive failed", exc = e.name, err = e.msg
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except Exception as e:
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debug "Receive failed", exc = e.name, err = e.msg
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raise e
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proc open*(d: DiscoveryProtocol) =
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# TODO allow binding to specific IP / IPv6 / etc
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let ta = initTAddress(IPv4_any(), d.address.udpPort)
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d.transp = newDatagramTransport(processClient, udata = d, local = ta)
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proc lookupRandom*(d: DiscoveryProtocol): Future[seq[Node]] {.inline.} =
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d.kademlia.lookupRandom()
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proc run(d: DiscoveryProtocol) {.async.} =
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while true:
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discard await d.lookupRandom()
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await sleepAsync(3000)
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trace "Discovered nodes", nodes = d.kademlia.nodesDiscovered
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proc bootstrap*(d: DiscoveryProtocol) {.async.} =
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await d.kademlia.bootstrap(d.bootstrapNodes)
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discard d.run()
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proc resolve*(d: DiscoveryProtocol, n: NodeId): Future[Node] =
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d.kademlia.resolve(n)
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proc randomNodes*(d: DiscoveryProtocol, count: int): seq[Node] {.inline.} =
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d.kademlia.randomNodes(count)
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when isMainModule:
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import logging, stew/byteutils
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const LOCAL_BOOTNODES = [
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"enode://6456719e7267e061161c88720287a77b80718d2a3a4ff5daeba614d029dc77601b75e32190aed1c9b0b9ccb6fac3bcf000f48e54079fa79e339c25d8e9724226@127.0.0.1:30301"
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]
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addHandler(newConsoleLogger())
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block:
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let m = hexToSeqByte"79664bff52ee17327b4a2d8f97d8fb32c9244d719e5038eb4f6b64da19ca6d271d659c3ad9ad7861a928ca85f8d8debfbe6b7ade26ad778f2ae2ba712567fcbd55bc09eb3e74a893d6b180370b266f6aaf3fe58a0ad95f7435bf3ddf1db940d20102f2cb842edbd4d182944382765da0ab56fb9e64a85a597e6bb27c656b4f1afb7e06b0fd4e41ccde6dba69a3c4a150845aaa4de2"
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var msgHash: MDigest[256]
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doAssert(validateMsgHash(m, msgHash))
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var remotePubkey: PublicKey
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doAssert(recoverMsgPublicKey(m, remotePubkey))
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let (cmdId, payload) = unpack(m)
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doAssert(payload == hexToSeqByte"f2cb842edbd4d182944382765da0ab56fb9e64a85a597e6bb27c656b4f1afb7e06b0fd4e41ccde6dba69a3c4a150845aaa4de2")
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doAssert(cmdId == cmdPong)
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doAssert(remotePubkey == initPublicKey("78de8a0916848093c73790ead81d1928bec737d565119932b98c6b100d944b7a95e94f847f689fc723399d2e31129d182f7ef3863f2b4c820abbf3ab2722344d"))
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let privKey = initPrivateKey("a2b50376a79b1a8c8a3296485572bdfbf54708bb46d3c25d73d2723aaaf6a617")
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# echo privKey
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# block:
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# var b = @[1.byte, 2, 3]
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# let m = pack(cmdPing, b.initBytesRange, privKey)
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# let (remotePubkey, cmdId, payload) = unpack(m)
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# doAssert(remotePubkey.raw_key.toHex == privKey.public_key.raw_key.toHex)
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var bootnodes = newSeq[ENode]()
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for item in LOCAL_BOOTNODES:
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bootnodes.add(initENode(item))
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let listenPort = Port(30310)
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var address = Address(udpPort: listenPort, tcpPort: listenPort)
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address.ip.family = IpAddressFamily.IPv4
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let discovery = newDiscoveryProtocol(privkey, address, bootnodes)
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echo discovery.thisNode.node.pubkey
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echo "this_node.id: ", discovery.thisNode.id.toHex()
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discovery.open()
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proc test() {.async.} =
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await discovery.bootstrap()
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waitFor test()
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