import options, macros, algorithm, random, tables, std_shims/[macros_shim, tables_shims], chronos, chronicles, libp2p/daemon/daemonapi, faststreams/output_stream, serialization, eth/async_utils, eth/p2p/p2p_protocol_dsl, ssz export daemonapi, p2pProtocol type Eth2Node* = ref object of RootObj daemon*: DaemonAPI peers*: Table[PeerID, Peer] protocolStates*: seq[RootRef] Peer* = ref object network*: Eth2Node id*: PeerID connectionState*: ConnectionState awaitedMessages: Table[CompressedMsgId, FutureBase] protocolStates*: seq[RootRef] EthereumNode = Eth2Node # This alias is needed for state_helpers below ProtocolInfoObj* = object name*: string messages*: seq[MessageInfo] index*: int # the position of the protocol in the # ordered list of supported protocols # Private fields: peerStateInitializer*: PeerStateInitializer networkStateInitializer*: NetworkStateInitializer handshake*: HandshakeStep disconnectHandler*: DisconnectionHandler ProtocolInfo* = ptr ProtocolInfoObj MessageInfo* = object name*: string # Private fields: thunk*: MessageHandler libp2pProtocol: string printer*: MessageContentPrinter nextMsgResolver*: NextMsgResolver CompressedMsgId = tuple protocolIndex, msgId: int PeerStateInitializer* = proc(peer: Peer): RootRef {.gcsafe.} NetworkStateInitializer* = proc(network: EthereumNode): RootRef {.gcsafe.} HandshakeStep* = proc(peer: Peer, handshakeStream: P2PStream): Future[void] {.gcsafe.} DisconnectionHandler* = proc(peer: Peer): Future[void] {.gcsafe.} MessageHandler* = proc(daemon: DaemonAPI, stream: P2PStream): Future[void] {.gcsafe.} MessageContentPrinter* = proc(msg: pointer): string {.gcsafe.} NextMsgResolver* = proc(msgData: SszReader, future: FutureBase) {.gcsafe.} ConnectionState* = enum None, Connecting, Connected, Disconnecting, Disconnected UntypedResponse = object peer*: Peer stream*: P2PStream Response*[MsgType] = distinct UntypedResponse Bytes = seq[byte] DisconnectionReason* = enum UselessPeer BreachOfProtocol PeerDisconnected* = object of CatchableError reason*: DisconnectionReason const defaultIncomingReqTimeout = 5000 defaultOutgoingReqTimeout = 10000 var gProtocols: seq[ProtocolInfo] # The variables above are immutable RTTI information. We need to tell # Nim to not consider them GcSafe violations: template allProtocols: auto = {.gcsafe.}: gProtocols proc `$`*(peer: Peer): string = $peer.id proc disconnect*(peer: Peer, reason: DisconnectionReason, notifyOtherPeer = false) {.async.} = # TODO: How should we notify the other peer? if peer.connectionState notin {Disconnecting, Disconnected}: peer.connectionState = Disconnecting await peer.network.daemon.disconnect(peer.id) peer.connectionState = Disconnected peer.network.peers.del(peer.id) template raisePeerDisconnected(msg: string, r: DisconnectionReason) = var e = newException(PeerDisconnected, msg) e.reason = r raise e proc disconnectAndRaise(peer: Peer, reason: DisconnectionReason, msg: string) {.async.} = let r = reason await peer.disconnect(reason) raisePeerDisconnected(msg, reason) proc init*(node: Eth2Node) {.async.} = node.daemon = await newDaemonApi({PSGossipSub}) node.daemon.userData = node init node.peers newSeq node.protocolStates, allProtocols.len for proto in allProtocols: if proto.networkStateInitializer != nil: node.protocolStates[proto.index] = proto.networkStateInitializer(node) for msg in proto.messages: if msg.libp2pProtocol.len > 0: await node.daemon.addHandler(@[msg.libp2pProtocol], msg.thunk) include eth/p2p/p2p_backends_helpers include eth/p2p/p2p_tracing proc readMsg(stream: P2PStream, MsgType: type, timeout = 10.seconds): Future[Option[MsgType]] {.async.} = var timeout = sleepAsync timeout var sizePrefix: uint32 var readSizePrefix = stream.transp.readExactly(addr sizePrefix, sizeof(sizePrefix)) await readSizePrefix or timeout if not readSizePrefix.finished: return var msgBytes = newSeq[byte](sizePrefix.int + sizeof(sizePrefix)) copyMem(addr msgBytes[0], addr sizePrefix, sizeof(sizePrefix)) var readBody = stream.transp.readExactly(addr msgBytes[sizeof(sizePrefix)], sizePrefix.int) await readBody or timeout if not readBody.finished: return let decoded = SSZ.decode(msgBytes, MsgType) try: return some(decoded) except SerializationError: return proc sendMsg(peer: Peer, protocolId: string, requestBytes: Bytes) {.async} = var stream = await peer.network.daemon.openStream(peer.id, @[protocolId]) # TODO how does openStream fail? Set a timeout here and handle it let sent = await stream.transp.write(requestBytes) # TODO: Should I check that `sent` is equal to the desired number of bytes proc sendBytes(stream: P2PStream, bytes: Bytes) {.async.} = let sent = await stream.transp.write(bytes) # TODO: Should I check that `sent` is equal to the desired number of bytes proc makeEth2Request(peer: Peer, protocolId: string, requestBytes: Bytes, ResponseMsg: type, timeout = 10.seconds): Future[Option[ResponseMsg]] {.async.} = var stream = await peer.network.daemon.openStream(peer.id, @[protocolId]) # TODO how does openStream fail? Set a timeout here and handle it let sent = await stream.transp.write(requestBytes) # TODO: Should I check that `sent` is equal to the desired number of bytes return await stream.readMsg(ResponseMsg, timeout) proc p2pStreamName(MsgType: type): string = mixin msgProtocol, protocolInfo, msgId MsgType.msgProtocol.protocolInfo.messages[MsgType.msgId].libp2pProtocol template handshakeImpl*(HandshakeTypeExpr: untyped, # TODO: we cannot use a type parameter above # because of the following Nim issue: # peerExpr: Peer, streamExpr: P2PStream, lazySendCall: Future[void], timeoutExpr: Duration): auto = # We make sure the inputs are evaluated only once. let stream = streamExpr peer = peerExpr timeout = timeoutExpr # TODO: This is a work-around for a Nim issue. Please note that it's # semantically wrong, so if you get a compilation failure, try to # remove it (perhaps Nim got fixed) type HandshakeType = type(HandshakeTypeExpr) proc asyncStep(stream: P2PStream): Future[HandshakeType] {.async.} = var stream = stream if stream == nil: stream = await openStream(peer.network.daemon, peer.id, @[p2pStreamName(HandshakeType)], # TODO openStream should accept Duration int milliseconds(timeout)) # Please pay attention that `lazySendCall` is evaluated lazily here. # For this reason `handshakeImpl` must remain a template. await lazySendCall let response = await readMsg(stream, HandshakeType, timeout) if response.isSome: return response.get else: await disconnectAndRaise(peer, BreachOfProtocol, "Handshake not completed in time") asyncStep(stream) proc getCompressedMsgId(MsgType: type): CompressedMsgId = mixin msgProtocol, protocolInfo, msgId (protocolIndex: MsgType.msgProtocol.protocolInfo.index, msgId: MsgType.msgId) proc nextMsg*(peer: Peer, MsgType: type): Future[MsgType] = ## This procs awaits a specific P2P message. ## Any messages received while waiting will be dispatched to their ## respective handlers. The designated message handler will also run ## to completion before the future returned by `nextMsg` is resolved. mixin msgProtocol, protocolInfo, msgId let awaitedMsgId = getCompressedMsgId(MsgType) let f = getOrDefault(peer.awaitedMessages, awaitedMsgId) if not f.isNil: return Future[MsgType](f) newFuture result peer.awaitedMessages[awaitedMsgId] = result proc resolveNextMsgFutures(peer: Peer, msg: auto) = type MsgType = type(msg) let msgId = getCompressedMsgId(MsgType) let future = peer.awaitedMessages.getOrDefault(msgId) if future != nil: Future[MsgType](future).complete msg proc init*(T: type Peer, network: Eth2Node, id: PeerID): Peer = new result result.id = id result.network = network result.awaitedMessages = initTable[CompressedMsgId, FutureBase]() result.connectionState = Connected newSeq result.protocolStates, allProtocols.len for i in 0 ..< allProtocols.len: let proto = allProtocols[i] if proto.peerStateInitializer != nil: result.protocolStates[i] = proto.peerStateInitializer(result) proc performProtocolHandshakes*(peer: Peer) {.async.} = var subProtocolsHandshakes = newSeqOfCap[Future[void]](allProtocols.len) for protocol in allProtocols: if protocol.handshake != nil: subProtocolsHandshakes.add((protocol.handshake)(peer, nil)) await all(subProtocolsHandshakes) proc getPeer*(node: Eth2Node, peerId: PeerID): Peer = result = node.peers.getOrDefault(peerId) if result == nil: result = Peer.init(node, peerId) node.peers[peerId] = result proc peerFromStream(daemon: DaemonAPI, stream: P2PStream): Peer = Eth2Node(daemon.userData).getPeer(stream.peer) template getRecipient(peer: Peer): Peer = peer # TODO: this should be removed eventually template getRecipient(stream: P2PStream): P2PStream = stream template getRecipient(response: Response): Peer = UntypedResponse(response).peer proc messagePrinter[MsgType](msg: pointer): string {.gcsafe.} = result = "" # TODO: uncommenting the line below increases the compile-time # tremendously (for reasons not yet known) # result = $(cast[ptr MsgType](msg)[]) proc initProtocol(name: string, peerInit: PeerStateInitializer, networkInit: NetworkStateInitializer): ProtocolInfoObj = result.name = name result.messages = @[] result.peerStateInitializer = peerInit result.networkStateInitializer = networkInit proc setEventHandlers(p: ProtocolInfo, handshake: HandshakeStep, disconnectHandler: DisconnectionHandler) = p.handshake = handshake p.disconnectHandler = disconnectHandler proc registerMsg(protocol: ProtocolInfo, name: string, thunk: MessageHandler, libp2pProtocol: string, printer: MessageContentPrinter) = protocol.messages.add MessageInfo(name: name, thunk: thunk, libp2pProtocol: libp2pProtocol, printer: printer) proc registerProtocol(protocol: ProtocolInfo) = # TODO: This can be done at compile-time in the future let pos = lowerBound(gProtocols, protocol) gProtocols.insert(protocol, pos) for i in 0 ..< gProtocols.len: gProtocols[i].index = i proc getRequestProtoName(fn: NimNode): NimNode = # `getCustomPragmaVal` doesn't work yet on regular nnkProcDef nodes # (TODO: file as an issue) let pragmas = fn.pragma if pragmas.kind == nnkPragma and pragmas.len > 0: for pragma in pragmas: if pragma.len > 0 and $pragma[0] == "libp2pProtocol": return pragma[1] error "All stream opening procs must have the 'libp2pProtocol' pragma specified.", fn template libp2pProtocol*(name, version: string) {.pragma.} proc p2pProtocolBackendImpl*(p: P2PProtocol): Backend = var response = ident"response" name_openStream = newTree(nnkPostfix, ident("*"), ident"openStream") outputStream = ident"outputStream" currentProtocolSym = ident"CurrentProtocol" Format = ident"SSZ" Option = bindSym "Option" UntypedResponse = bindSym "UntypedResponse" Response = bindSym "Response" DaemonAPI = bindSym "DaemonAPI" P2PStream = ident "P2PStream" # XXX: Binding the int type causes instantiation failure for some reason # Int = bindSym "int" Int = ident "int" Void = ident "void" Peer = bindSym "Peer" Eth2Node = bindSym "Eth2Node" writeField = bindSym "writeField" getOutput = bindSym "getOutput" messagePrinter = bindSym "messagePrinter" getRecipient = bindSym "getRecipient" peerFromStream = bindSym "peerFromStream" makeEth2Request = bindSym "makeEth2Request" sendMsg = bindSym "sendMsg" sendBytes = bindSym "sendBytes" resolveNextMsgFutures = bindSym "resolveNextMsgFutures" milliseconds = bindSym "milliseconds" registerMsg = bindSym "registerMsg" initProtocol = bindSym "initProtocol" bindSymOp = bindSym "bindSym" msgRecipient = ident"msgRecipient" sendTo = ident"sendTo" writer = ident"writer" recordStartMemo = ident"recordStartMemo" receivedMsg = ident"msg" daemon = ident "daemon" stream = ident "stream" await = ident "await" peerIdent = ident "peer" new result result.PeerType = Peer result.NetworkType = Eth2Node result.registerProtocol = bindSym "registerProtocol" result.setEventHandlers = bindSym "setEventHandlers" result.afterProtocolInit = proc (p: P2PProtocol) = p.onPeerConnected.params.add newIdentDefs(ident"handshakeStream", P2PStream) result.implementMsg = proc (p: P2PProtocol, msg: Message, resp: Message = nil) = let n = msg.procDef msgId = newLit(msg.id) msgIdent = n.name msgName = $msgIdent msgKind = msg.kind msgRecName = msg.recIdent responseRecord = if resp != nil: resp.recIdent else: nil userPragmas = n.pragma var # variables used in the sending procs appendParams = newNimNode(nnkStmtList) paramsToWrite = newSeq[NimNode](0) # variables used in the receiving procs tracing = newNimNode(nnkStmtList) # nodes to store the user-supplied message handling proc if present userHandlerProc: NimNode = nil userHandlerCall: NimNode = nil awaitUserHandler = newStmtList() if n.body.kind != nnkEmpty: # This is the call to the user supplied handler. # Here we add only the initial params, the rest will be added later. userHandlerCall = newCall(msg.userHandler.name) # When there is a user handler, it must be awaited in the thunk proc. # Above, by default `awaitUserHandler` is set to a no-op statement list. awaitUserHandler = newCall(await, userHandlerCall) var extraDefs: NimNode if msgKind == msgRequest: # Request procs need an extra param - the stream where the response # should be written: msg.userHandler.params.insert(1, newIdentDefs(stream, P2PStream)) userHandlerCall.add stream let peer = msg.userHandler.params[2][0] extraDefs = quote do: # Jump through some hoops to work aroung # https://github.com/nim-lang/Nim/issues/6248 let `response` = `Response`[`responseRecord`]( `UntypedResponse`(peer: `peer`, stream: `stream`)) # Resolve the Eth2Peer from the LibP2P data received in the thunk userHandlerCall.add peerIdent msg.userHandler.addPreludeDefs extraDefs p.outRecvProcs.add msg.userHandler elif msgName == "status": #awaitUserHandler = quote do: # `await` `handshake`(`peerIdent`, `stream`) discard # TODO: revisit this for param, paramType in n.typedParams(skip = 1): paramsToWrite.add param # If there is user message handler, we'll place a call to it by # unpacking the fields of the received message: if userHandlerCall != nil: userHandlerCall.add quote do: get(`receivedMsg`).`param` # newDotExpr(newCall("get", receivedMsg), param) when tracingEnabled: tracing = quote do: logReceivedMsg(`stream`.peer, `receivedMsg`.get) let requestDataTimeout = newCall(milliseconds, newLit(defaultIncomingReqTimeout)) let thunkName = ident(msgName & "_thunk") var thunkProc = quote do: proc `thunkName`(`daemon`: `DaemonAPI`, `stream`: `P2PStream`) {.async, gcsafe.} = var `receivedMsg` = `await` readMsg(`stream`, `msgRecName`, `requestDataTimeout`) if `receivedMsg`.isNone: # TODO: This peer is misbehaving, perhaps we should penalize him somehow return let `peerIdent` = `peerFromStream`(`daemon`, `stream`) `tracing` `awaitUserHandler` `resolveNextMsgFutures`(`peerIdent`, get(`receivedMsg`)) for p in userPragmas: thunkProc.addPragma p p.outRecvProcs.add thunkProc var msgSendProc = n let msgSendProcName = n.name p.outSendProcs.add msgSendProc # TODO: check that the first param has the correct type msgSendProc.params[1][0] = sendTo msgSendProc.addPragma ident"gcsafe" # Add a timeout parameter for all request procs case msgKind of msgRequest: # Add a timeout parameter for all request procs msgSendProc.params.add msg.timeoutParam of msgResponse: # A response proc must be called with a response object that originates # from a certain request. Here we change the Peer parameter at position # 1 to the correct strongly-typed ResponseType. The incoming procs still # gets the normal Peer paramter. let ResponseType = newTree(nnkBracketExpr, Response, msgRecName) msgSendProc.params[1][1] = ResponseType p.outSendProcs.add quote do: template send*(r: `ResponseType`, args: varargs[untyped]): auto = `msgSendProcName`(r, args) else: discard # We change the return type of the sending proc to a Future. # If this is a request proc, the future will return the response record. let rt = if msgKind != msgRequest: Void else: newTree(nnkBracketExpr, Option, responseRecord) msgSendProc.params[0] = newTree(nnkBracketExpr, ident("Future"), rt) if msgKind == msgHandshake: var rawSendProc = msgName & "RawSend" handshakeTypeName = $msgRecName handshakeExchanger = msg.createSendProc(nnkMacroDef) paramsArray = newTree(nnkBracket).appendAllParams(handshakeExchanger) bindSym = ident "bindSym" getAst = ident "getAst" handshakeImpl = ident "handshakeImpl" # TODO: macros.body triggers an assertion error when the proc type is nnkMacroDef handshakeExchanger[6] = quote do: let stream = ident"handshakeStream" rawSendProc = `bindSymOp` `rawSendProc` params = `paramsArray` lazySendCall = newCall(rawSendProc, params) peer = params[0] timeout = params[^1] lazySendCall[1] = stream lazySendCall.del(lazySendCall.len - 1) return `getAst`(`handshakeImpl`(`msgRecName`, peer, stream, lazySendCall, timeout)) p.outSendProcs.add handshakeExchanger msgSendProc.params[1][1] = P2PStream msgSendProc.name = ident rawSendProc else: # Make the send proc public msgSendProc.name = msg.identWithExportMarker let initWriter = quote do: var `outputStream` = init OutputStream var `writer` = init(WriterType(`Format`), `outputStream`) var `recordStartMemo` = beginRecord(`writer`, `msgRecName`) for param in paramsToWrite: appendParams.add newCall(writeField, writer, newLit($param), param) when tracingEnabled: appendParams.add logSentMsgFields(msgRecipient, protocol, msgName, paramsToWrite) let msgBytes = ident"msgBytes" let finalizeRequest = quote do: endRecord(`writer`, `recordStartMemo`) let `msgBytes` = `getOutput`(`outputStream`) var msgProto = newLit("") let sendCall = if msgKind != msgResponse: msgProto = getRequestProtoName(n) when false: var openStreamProc = n.copyNimTree var openStreamProc.name = name_openStream openStreamProc.params.insert 1, newIdentDefs(ident"T", msgRecName) if msgKind == msgRequest: let timeout = msg.timeoutParam[0] quote: `makeEth2Request`(`msgRecipient`, `msgProto`, `msgBytes`, `responseRecord`, `timeout`) elif msgId.intVal == 0: quote: `sendBytes`(`sendTo`, `msgBytes`) else: quote: `sendMsg`(`msgRecipient`, `msgProto`, `msgBytes`) else: quote: `sendBytes`(`UntypedResponse`(`sendTo`).stream, `msgBytes`) msgSendProc.body = quote do: let `msgRecipient` = `getRecipient`(`sendTo`) `initWriter` `appendParams` `finalizeRequest` return `sendCall` p.outProcRegistrations.add( newCall(registerMsg, p.protocolInfoVar, newLit(msgName), thunkName, msgProto, newTree(nnkBracketExpr, messagePrinter, msgRecName))) result.implementProtocolInit = proc (p: P2PProtocol): NimNode = return newCall(initProtocol, newLit(p.name), p.peerInit, p.netInit) proc makeMessageHandler[MsgType](msgHandler: proc(msg: MsgType)): P2PPubSubCallback = result = proc(api: DaemonAPI, ticket: PubsubTicket, msg: PubSubMessage): Future[bool] {.async.} = msgHandler SSZ.decode(msg.data, MsgType) return true proc subscribe*[MsgType](node: EthereumNode, topic: string, msgHandler: proc(msg: MsgType)) {.async.} = discard await node.daemon.pubsubSubscribe(topic, makeMessageHandler(msgHandler)) proc broadcast*(node: Eth2Node, topic: string, msg: auto) = traceAsyncErrors node.daemon.pubsubPublish(topic, SSZ.encode(msg)) # TODO: # At the moment, this is just a compatiblity shim for the existing RLPx functionality. # The filtering is not implemented properly yet. iterator randomPeers*(node: EthereumNode, maxPeers: int, Protocol: type): Peer = var peers = newSeq[Peer]() for _, peer in pairs(node.peers): peers.add peer shuffle peers if peers.len > maxPeers: peers.setLen(maxPeers) for p in peers: yield p