import macros, tables, algorithm, deques, hashes, options, typetraits, std_shims/macros_shim, chronicles, nimcrypto, chronos, eth/[rlp, common, keys, async_utils], private/p2p_types, kademlia, auth, rlpxcrypt, enode, p2p_protocol_dsl when useSnappy: import snappy const devp2pSnappyVersion* = 5 export options, p2pProtocol logScope: topics = "rlpx" type ResponderWithId*[MsgType] = object peer*: Peer reqId*: int ResponderWithoutId*[MsgType] = distinct Peer const devp2pVersion* = 4 maxMsgSize = 1024 * 1024 HandshakeTimeout = BreachOfProtocol include p2p_tracing when tracingEnabled: import eth/common/eth_types_json_serialization export # XXX: This is a work-around for a Nim issue. # See a more detailed comment in p2p_tracing.nim init, writeValue, getOutput proc init*[MsgName](T: type ResponderWithId[MsgName], peer: Peer, reqId: int): T = T(peer: peer, reqId: reqId) proc init*[MsgName](T: type ResponderWithoutId[MsgName], peer: Peer): T = T(peer) chronicles.formatIt(Peer): $(it.remote) include p2p_backends_helpers proc disconnect*(peer: Peer, reason: DisconnectionReason, notifyOtherPeer = false) {.gcsafe, async.} 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(r) raisePeerDisconnected(msg, r) var gDevp2pInfo: ProtocolInfo template devp2pInfo: auto = {.gcsafe.}: gDevp2pInfo # Dispatcher # proc hash(d: Dispatcher): int = hash(d.protocolOffsets) proc `==`(lhs, rhs: Dispatcher): bool = lhs.activeProtocols == rhs.activeProtocols proc describeProtocols(d: Dispatcher): string = result = "" for protocol in d.activeProtocols: if result.len != 0: result.add(',') for c in protocol.name: result.add(c) proc numProtocols(d: Dispatcher): int = d.activeProtocols.len proc getDispatcher(node: EthereumNode, otherPeerCapabilities: openarray[Capability]): Dispatcher = # TODO: sub-optimal solution until progress is made here: # https://github.com/nim-lang/Nim/issues/7457 # We should be able to find an existing dispatcher without allocating a new one new result newSeq(result.protocolOffsets, allProtocols.len) result.protocolOffsets.fill -1 var nextUserMsgId = 0x10 for localProtocol in node.protocols: let idx = localProtocol.index block findMatchingProtocol: for remoteCapability in otherPeerCapabilities: if localProtocol.name == remoteCapability.name and localProtocol.version == remoteCapability.version: result.protocolOffsets[idx] = nextUserMsgId nextUserMsgId += localProtocol.messages.len break findMatchingProtocol template copyTo(src, dest; index: int) = for i in 0 ..< src.len: dest[index + i] = addr src[i] result.messages = newSeq[ptr MessageInfo](nextUserMsgId) devp2pInfo.messages.copyTo(result.messages, 0) for localProtocol in node.protocols: let idx = localProtocol.index if result.protocolOffsets[idx] != -1: result.activeProtocols.add localProtocol localProtocol.messages.copyTo(result.messages, result.protocolOffsets[idx]) proc getMsgName*(peer: Peer, msgId: int): string = if not peer.dispatcher.isNil and msgId < peer.dispatcher.messages.len: return peer.dispatcher.messages[msgId].name else: return case msgId of 0: "hello" of 1: "disconnect" of 2: "ping" of 3: "pong" else: $msgId proc getMsgMetadata*(peer: Peer, msgId: int): (ProtocolInfo, ptr MessageInfo) = doAssert msgId >= 0 if msgId <= devp2pInfo.messages[^1].id: return (devp2pInfo, addr devp2pInfo.messages[msgId]) if msgId < peer.dispatcher.messages.len: for i in 0 ..< allProtocols.len: let offset = peer.dispatcher.protocolOffsets[i] if offset != -1 and offset + allProtocols[i].messages[^1].id >= msgId: return (allProtocols[i], peer.dispatcher.messages[msgId]) # Protocol info objects # proc initProtocol(name: string, version: int, peerInit: PeerStateInitializer, networkInit: NetworkStateInitializer): ProtocolInfoObj = result.name = name result.version = version result.messages = @[] result.peerStateInitializer = peerInit result.networkStateInitializer = networkInit proc setEventHandlers(p: ProtocolInfo, handshake: HandshakeStep, disconnectHandler: DisconnectionHandler) = p.handshake = handshake p.disconnectHandler = disconnectHandler func asCapability*(p: ProtocolInfo): Capability = result.name = p.name result.version = p.version func nameStr*(p: ProtocolInfo): string = result = newStringOfCap(3) for c in p.name: result.add(c) # XXX: this used to be inline, but inline procs # cannot be passed to closure params proc cmp*(lhs, rhs: ProtocolInfo): int = for i in 0..2: if lhs.name[i] != rhs.name[i]: return int16(lhs.name[i]) - int16(rhs.name[i]) return 0 proc nextMsgResolver[MsgType](msgData: Rlp, future: FutureBase) {.gcsafe.} = var reader = msgData Future[MsgType](future).complete reader.readRecordType(MsgType, MsgType.rlpFieldsCount > 1) proc registerMsg(protocol: ProtocolInfo, id: int, name: string, thunk: ThunkProc, printer: MessageContentPrinter, requestResolver: RequestResolver, nextMsgResolver: NextMsgResolver) = if protocol.messages.len <= id: protocol.messages.setLen(id + 1) protocol.messages[id] = MessageInfo(id: id, name: name, thunk: thunk, printer: printer, requestResolver: requestResolver, nextMsgResolver: nextMsgResolver) proc registerProtocol(protocol: ProtocolInfo) = # TODO: This can be done at compile-time in the future if protocol.version > 0: let pos = lowerBound(gProtocols, protocol) gProtocols.insert(protocol, pos) for i in 0 ..< gProtocols.len: gProtocols[i].index = i else: gDevp2pInfo = protocol # Message composition and encryption # proc perPeerMsgIdImpl(peer: Peer, proto: ProtocolInfo, msgId: int): int {.inline.} = result = msgId if not peer.dispatcher.isNil: result += peer.dispatcher.protocolOffsets[proto.index] template getPeer(peer: Peer): auto = peer template getPeer(responder: ResponderWithId): auto = responder.peer template getPeer(responder: ResponderWithoutId): auto = Peer(responder) proc supports*(peer: Peer, proto: ProtocolInfo): bool {.inline.} = peer.dispatcher.protocolOffsets[proto.index] != -1 proc supports*(peer: Peer, Protocol: type): bool {.inline.} = ## Checks whether a Peer supports a particular protocol peer.supports(Protocol.protocolInfo) template perPeerMsgId(peer: Peer, MsgType: type): int = perPeerMsgIdImpl(peer, MsgType.msgProtocol.protocolInfo, MsgType.msgId) proc invokeThunk*(peer: Peer, msgId: int, msgData: var Rlp): Future[void] = template invalidIdError: untyped = raise newException(UnsupportedMessageError, "RLPx message with an invalid id " & $msgId & " on a connection supporting " & peer.dispatcher.describeProtocols) if msgId >= peer.dispatcher.messages.len: invalidIdError() let thunk = peer.dispatcher.messages[msgId].thunk if thunk == nil: invalidIdError() return thunk(peer, msgId, msgData) template compressMsg(peer: Peer, data: Bytes): Bytes = when useSnappy: if peer.snappyEnabled: snappy.compress(data) else: data else: data proc sendMsg*(peer: Peer, data: Bytes) {.gcsafe, async.} = try: var cipherText = encryptMsg(peer.compressMsg(data), peer.secretsState) var res = await peer.transport.write(cipherText) if res != len(cipherText): # This is ECONNRESET or EPIPE case when remote peer disconnected. await peer.disconnect(TcpError) except: await peer.disconnect(TcpError) raise proc send*[Msg](peer: Peer, msg: Msg): Future[void] = logSentMsg(peer, msg) var rlpWriter = initRlpWriter() rlpWriter.append perPeerMsgId(peer, Msg) rlpWriter.appendRecordType(msg, Msg.rlpFieldsCount > 1) peer.sendMsg rlpWriter.finish proc registerRequest(peer: Peer, timeout: Duration, responseFuture: FutureBase, responseMsgId: int): int = inc peer.lastReqId result = peer.lastReqId let timeoutAt = Moment.fromNow(timeout) let req = OutstandingRequest(id: result, future: responseFuture, timeoutAt: timeoutAt) peer.outstandingRequests[responseMsgId].addLast req doAssert(not peer.dispatcher.isNil) let requestResolver = peer.dispatcher.messages[responseMsgId].requestResolver proc timeoutExpired(udata: pointer) = requestResolver(nil, responseFuture) addTimer(timeoutAt, timeoutExpired, nil) proc resolveResponseFuture(peer: Peer, msgId: int, msg: pointer, reqId: int) = logScope: msg = peer.dispatcher.messages[msgId].name msgContents = peer.dispatcher.messages[msgId].printer(msg) receivedReqId = reqId remotePeer = peer.remote template resolve(future) = (peer.dispatcher.messages[msgId].requestResolver)(msg, future) template outstandingReqs: auto = peer.outstandingRequests[msgId] if reqId == -1: # XXX: This is a response from an ETH-like protocol that doesn't feature # request IDs. Handling the response is quite tricky here because this may # be a late response to an already timed out request or a valid response # from a more recent one. # # We can increase the robustness by recording enough features of the # request so we can recognize the matching response, but this is not very # easy to do because our peers are allowed to send partial responses. # # A more generally robust approach is to maintain a set of the wanted # data items and then to periodically look for items that have been # requested long time ago, but are still missing. New requests can be # issues for such items potentially from another random peer. var expiredRequests = 0 for req in outstandingReqs: if not req.future.finished: break inc expiredRequests outstandingReqs.shrink(fromFirst = expiredRequests) if outstandingReqs.len > 0: let oldestReq = outstandingReqs.popFirst resolve oldestReq.future else: trace "late or duplicate reply for a RLPx request" else: # TODO: This is not completely sound because we are still using a global # `reqId` sequence (the problem is that we might get a response ID that # matches a request ID for a different type of request). To make the code # correct, we can use a separate sequence per response type, but we have # to first verify that the other Ethereum clients are supporting this # correctly (because then, we'll be reusing the same reqIds for different # types of requests). Alternatively, we can assign a separate interval in # the `reqId` space for each type of response. if reqId > peer.lastReqId: warn "RLPx response without a matching request" return var idx = 0 while idx < outstandingReqs.len: template req: auto = outstandingReqs()[idx] if req.future.finished: doAssert req.timeoutAt <= Moment.now() # Here we'll remove the expired request by swapping # it with the last one in the deque (if necessary): if idx != outstandingReqs.len - 1: req = outstandingReqs.popLast continue else: outstandingReqs.shrink(fromLast = 1) # This was the last item, so we don't have any # more work to do: return if req.id == reqId: resolve req.future # Here we'll remove the found request by swapping # it with the last one in the deque (if necessary): if idx != outstandingReqs.len - 1: req = outstandingReqs.popLast else: outstandingReqs.shrink(fromLast = 1) return inc idx debug "late or duplicate reply for a RLPx request" proc recvMsg*(peer: Peer): Future[tuple[msgId: int, msgData: Rlp]] {.async.} = ## This procs awaits the next complete RLPx message in the TCP stream var headerBytes: array[32, byte] await peer.transport.readExactly(addr headerBytes[0], 32) var msgSize: int if decryptHeaderAndGetMsgSize(peer.secretsState, headerBytes, msgSize) != RlpxStatus.Success: await peer.disconnectAndRaise(BreachOfProtocol, "Cannot decrypt RLPx frame header") if msgSize > maxMsgSize: await peer.disconnectAndRaise(BreachOfProtocol, "RLPx message exceeds maximum size") let remainingBytes = encryptedLength(msgSize) - 32 # TODO: Migrate this to a thread-local seq # JACEK: # or pass it in, allowing the caller to choose - they'll likely be in a # better position to decide if buffer should be reused or not. this will # also be useuful for chunked messages where part of the buffer may have # been processed and needs filling in var encryptedBytes = newSeq[byte](remainingBytes) await peer.transport.readExactly(addr encryptedBytes[0], len(encryptedBytes)) let decryptedMaxLength = decryptedLength(msgSize) var decryptedBytes = newSeq[byte](decryptedMaxLength) decryptedBytesCount = 0 if decryptBody(peer.secretsState, encryptedBytes, msgSize, decryptedBytes, decryptedBytesCount) != RlpxStatus.Success: await peer.disconnectAndRaise(BreachOfProtocol, "Cannot decrypt RLPx frame body") decryptedBytes.setLen(decryptedBytesCount) when useSnappy: if peer.snappyEnabled: decryptedBytes = snappy.uncompress(decryptedBytes) if decryptedBytes.len == 0: await peer.disconnectAndRaise(BreachOfProtocol, "Snappy uncompress encountered malformed data") var rlp = rlpFromBytes(decryptedBytes.toRange) try: let msgid = rlp.read(int) return (msgId, rlp) except RlpError: await peer.disconnectAndRaise(BreachOfProtocol, "Cannot read RLPx message id") proc checkedRlpRead(peer: Peer, r: var Rlp, MsgType: type): auto {.inline.} = let tmp = r when defined(release): return r.read(MsgType) else: try: return r.read(MsgType) except: # echo "Failed rlp.read:", tmp.inspect debug "Failed rlp.read", peer = peer, msg = MsgType.name, exception = getCurrentExceptionMsg() # dataHex = r.rawData.toSeq().toHex() raise proc waitSingleMsg(peer: Peer, MsgType: type): Future[MsgType] {.async.} = let wantedId = peer.perPeerMsgId(MsgType) while true: var (nextMsgId, nextMsgData) = await peer.recvMsg() if nextMsgId == wantedId: try: result = checkedRlpRead(peer, nextMsgData, MsgType) logReceivedMsg(peer, result) return except RlpError: await peer.disconnectAndRaise(BreachOfProtocol, "Invalid RLPx message body") elif nextMsgId == 1: # p2p.disconnect let reason = DisconnectionReason nextMsgData.listElem(0).toInt(uint32) await peer.disconnect(reason) raisePeerDisconnected("Unexpected disconnect", reason) else: warn "Dropped RLPX message", msg = peer.dispatcher.messages[nextMsgId].name proc nextMsg*(peer: Peer, MsgType: type): Future[MsgType] = ## This procs awaits a specific RLPx 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. let wantedId = peer.perPeerMsgId(MsgType) let f = peer.awaitedMessages[wantedId] if not f.isNil: return Future[MsgType](f) initFuture result peer.awaitedMessages[wantedId] = result # Known fatal errors are handled inside dispatchMessages. # Errors we are currently unaware of are caught in the dispatchMessages # callback. There they will be logged if CatchableError and quit on Defect. # Non fatal errors such as the current CatchableError could be moved and # handled a layer lower for clarity (and consistency), as also the actual # message handler code as the TODO mentions already. proc dispatchMessages*(peer: Peer) {.async.} = while peer.connectionState notin {Disconnecting, Disconnected}: var msgId: int var msgData: Rlp try: (msgId, msgData) = await peer.recvMsg() except TransportError: # Note: This will also catch TransportIncompleteError. TransportError will # here usually occur when a read is attempted when the transport is # already closed. TransportIncompleteError when the transport is closed # during read. case peer.connectionState of Connected: # Dropped connection, still need to cleanup the peer. # This could be seen as bad behaving peer. trace "Dropped connection", peer await peer.disconnect(ClientQuitting, false) return of Disconnecting, Disconnected: # Graceful disconnect, can still cause TransportIncompleteError as it # could be that this loop was waiting at recvMsg(). return else: # Connection dropped while `Connecting` (in rlpxConnect/rlpxAccept). return except PeerDisconnected: return if msgId == 1: # p2p.disconnect let reason = msgData.listElem(0).toInt(uint32).DisconnectionReason await peer.disconnect(reason, false) break try: await peer.invokeThunk(msgId, msgData) except RlpError: debug "RlpError, ending dispatchMessages loop", peer, msg = peer.getMsgName(msgId) await peer.disconnect(BreachOfProtocol, true) return except CatchableError: warn "Error while handling RLPx message", peer, msg = peer.getMsgName(msgId), err = getCurrentExceptionMsg() # TODO: Hmm, this can be safely moved into the message handler thunk. # The documentation will need to be updated, explaning the fact that # nextMsg will be resolved only if the message handler has executed # successfully. if peer.awaitedMessages[msgId] != nil: let msgInfo = peer.dispatcher.messages[msgId] try: (msgInfo.nextMsgResolver)(msgData, peer.awaitedMessages[msgId]) except: # TODO: Handling errors here must be investigated more carefully. # They also are supposed to be handled at the call-site where # `nextMsg` is used. debug "nextMsg resolver failed, ending dispatchMessages loop", peer, err = getCurrentExceptionMsg() await peer.disconnect(BreachOfProtocol, true) return peer.awaitedMessages[msgId] = nil proc p2pProtocolBackendImpl*(protocol: P2PProtocol): Backend = let resultIdent = ident "result" Peer = bindSym "Peer" EthereumNode = bindSym "EthereumNode" initRlpWriter = bindSym "initRlpWriter" rlpFromBytes = bindSym "rlpFromBytes" append = bindSym("append", brForceOpen) read = bindSym("read", brForceOpen) checkedRlpRead = bindSym "checkedRlpRead" startList = bindSym "startList" safeEnterList = bindSym "safeEnterList" finish = bindSym "finish" messagePrinter = bindSym "messagePrinter" nextMsgResolver = bindSym "nextMsgResolver" registerRequest = bindSym "registerRequest" requestResolver = bindSym "requestResolver" resolveResponseFuture = bindSym "resolveResponseFuture" sendMsg = bindSym "sendMsg" nextMsg = bindSym "nextMsg" initProtocol = bindSym"initProtocol" registerMsg = bindSym "registerMsg" perPeerMsgId = bindSym "perPeerMsgId" perPeerMsgIdImpl = bindSym "perPeerMsgIdImpl" linkSendFailureToReqFuture = bindSym "linkSendFailureToReqFuture" handshakeImpl = bindSym "handshakeImpl" ResponderWithId = bindSym "ResponderWithId" ResponderWithoutId = bindSym "ResponderWithoutId" isSubprotocol = protocol.version > 0 if protocol.shortName.len == 0: protocol.shortName = protocol.name # By convention, all Ethereum protocol names must be abbreviated to 3 letters doAssert protocol.shortName.len == 3 new result result.registerProtocol = bindSym "registerProtocol" result.setEventHandlers = bindSym "setEventHandlers" result.PeerType = Peer result.NetworkType = EthereumNode result.ResponderType = if protocol.useRequestIds: ResponderWithId else: ResponderWithoutId result.implementMsg = proc (msg: Message) = var msgId = msg.id msgIdent = msg.ident msgName = $msgIdent msgRecName = msg.recIdent responseMsgId = if msg.response != nil: msg.response.id else: -1 ResponseRecord = if msg.response != nil: msg.response.recIdent else: nil hasReqId = msg.hasReqId protocol = msg.protocol userPragmas = msg.procDef.pragma # variables used in the sending procs peerOrResponder = ident"peerOrResponder" rlpWriter = ident"writer" perPeerMsgIdVar = ident"perPeerMsgId" # variables used in the receiving procs receivedRlp = ident"rlp" receivedMsg = ident"msg" var readParams = newNimNode(nnkStmtList) paramsToWrite = newSeq[NimNode](0) appendParams = newNimNode(nnkStmtList) if hasReqId: # Messages using request Ids readParams.add quote do: let `reqIdVar` = `read`(`receivedRlp`, int) case msg.kind of msgRequest: let reqToResponseOffset = responseMsgId - msgId let responseMsgId = quote do: `perPeerMsgIdVar` + `reqToResponseOffset` # Each request is registered so we can resolve it when the response # arrives. There are two types of protocols: LES-like protocols use # explicit `reqId` sent over the wire, while the ETH wire protocol # assumes there is one outstanding request at a time (if there are # multiple requests we'll resolve them in FIFO order). let registerRequestCall = newCall(registerRequest, peerVar, msg.timeoutParam[0], resultIdent, responseMsgId) if hasReqId: appendParams.add quote do: initFuture `resultIdent` let `reqIdVar` = `registerRequestCall` paramsToWrite.add reqIdVar else: appendParams.add quote do: initFuture `resultIdent` discard `registerRequestCall` of msgResponse: if hasReqId: paramsToWrite.add newDotExpr(peerOrResponder, reqIdVar) of msgHandshake, msgNotification: discard for param, paramType in msg.procDef.typedParams(skip = 1): # This is a fragment of the sending proc that # serializes each of the passed parameters: paramsToWrite.add param # The received RLP data is deserialized to a local variable of # the message-specific type. This is done field by field here: let msgNameLit = newLit(msgName) readParams.add quote do: `receivedMsg`.`param` = `checkedRlpRead`(`peerVar`, `receivedRlp`, `paramType`) let paramCount = paramsToWrite.len readParamsPrelude = if paramCount > 1: newCall(safeEnterList, receivedRlp) else: newStmtList() when tracingEnabled: readParams.add newCall(bindSym"logReceivedMsg", peerVar, receivedMsg) let callResolvedResponseFuture = if msg.kind == msgResponse: newCall(resolveResponseFuture, peerVar, newCall(perPeerMsgId, peerVar, msgRecName), newCall("addr", receivedMsg), if hasReqId: reqIdVar else: newLit(-1)) else: newStmtList() var userHandlerParams = @[peerVar] if hasReqId: userHandlerParams.add reqIdVar let awaitUserHandler = msg.genAwaitUserHandler(receivedMsg, userHandlerParams) thunkName = ident(msgName & "_thunk") msg.defineThunk quote do: proc `thunkName`(`peerVar`: `Peer`, _: int, data: Rlp) {.async, gcsafe.} = var `receivedRlp` = data var `receivedMsg` {.noinit.}: `msgRecName` `readParamsPrelude` `readParams` `awaitUserHandler` `callResolvedResponseFuture` var sendProc = msg.createSendProc(isRawSender = (msg.kind == msgHandshake)) sendProc.def.params[1][0] = peerOrResponder let msgBytes = ident"msgBytes" finalizeRequest = quote do: let `msgBytes` = `finish`(`rlpWriter`) var sendCall = newCall(sendMsg, peerVar, msgBytes) let senderEpilogue = if msg.kind == msgRequest: # In RLPx requests, the returned future was allocated here and passed # to `registerRequest`. It's already assigned to the result variable # of the proc, so we just wait for the sending operation to complete # and we return in a normal way. (the waiting is done, so we can catch # any possible errors). quote: `linkSendFailureToReqFuture`(`sendCall`, `resultIdent`) else: # In normal RLPx messages, we are returning the future returned by the # `sendMsg` call. quote: return `sendCall` let perPeerMsgIdValue = if isSubprotocol: newCall(perPeerMsgIdImpl, peerVar, protocol.protocolInfoVar, newLit(msgId)) else: newLit(msgId) if paramCount > 1: # In case there are more than 1 parameter, # the params must be wrapped in a list: appendParams = newStmtList( newCall(startList, rlpWriter, newLit(paramCount)), appendParams) for param in paramsToWrite: appendParams.add newCall(append, rlpWriter, param) let initWriter = quote do: var `rlpWriter` = `initRlpWriter`() const `perProtocolMsgIdVar` = `msgId` let `perPeerMsgIdVar` = `perPeerMsgIdValue` `append`(`rlpWriter`, `perPeerMsgIdVar`) when tracingEnabled: appendParams.add logSentMsgFields(peerVar, protocol, msgId, paramsToWrite) # let paramCountNode = newLit(paramCount) sendProc.setBody quote do: let `peerVar` = getPeer(`peerOrResponder`) `initWriter` `appendParams` `finalizeRequest` `senderEpilogue` if msg.kind == msgHandshake: discard msg.createHandshakeTemplate(sendProc.def.name, handshakeImpl, nextMsg) protocol.outProcRegistrations.add( newCall(registerMsg, protocol.protocolInfoVar, newLit(msgId), newLit(msgName), thunkName, newTree(nnkBracketExpr, messagePrinter, msgRecName), newTree(nnkBracketExpr, requestResolver, msgRecName), newTree(nnkBracketExpr, nextMsgResolver, msgRecName))) result.implementProtocolInit = proc (protocol: P2PProtocol): NimNode = return newCall(initProtocol, newLit(protocol.shortName), newLit(protocol.version), protocol.peerInit, protocol.netInit) p2pProtocol devp2p(version = 0, shortName = "p2p"): proc hello(peer: Peer, version: uint, clientId: string, capabilities: seq[Capability], listenPort: uint, nodeId: array[RawPublicKeySize, byte]) proc sendDisconnectMsg(peer: Peer, reason: DisconnectionReason) proc ping(peer: Peer) = discard peer.pong() proc pong(peer: Peer) = discard proc removePeer(network: EthereumNode, peer: Peer) = # It is necessary to check if peer.remote still exists. The connection might # have been dropped already from the peers side. # E.g. when receiving a p2p.disconnect message from a peer, a race will happen # between which side disconnects first. if network.peerPool != nil and not peer.remote.isNil and peer.remote in network.peerPool.connectedNodes: network.peerPool.connectedNodes.del(peer.remote) dec(nimbusStats.num_peers) # Note: we need to do this check as disconnect (and thus removePeer) # currently can get called before the dispatcher is initialized. if not peer.dispatcher.isNil: for observer in network.peerPool.observers.values: if not observer.onPeerDisconnected.isNil: if observer.protocol.isNil or peer.supports(observer.protocol): observer.onPeerDisconnected(peer) proc callDisconnectHandlers(peer: Peer, reason: DisconnectionReason): Future[void] = var futures = newSeqOfCap[Future[void]](allProtocols.len) for protocol in peer.dispatcher.activeProtocols: if protocol.disconnectHandler != nil: futures.add((protocol.disconnectHandler)(peer, reason)) return all(futures) proc disconnect*(peer: Peer, reason: DisconnectionReason, notifyOtherPeer = false) {.async.} = if peer.connectionState notin {Disconnecting, Disconnected}: peer.connectionState = Disconnecting # Do this first so sub-protocols have time to clean up and stop sending # before this node closes transport to remote peer if not peer.dispatcher.isNil: # In case of `CatchableError` in any of the handlers, this will be logged. # Other handlers will still execute. # In case of `Defect` in any of the handlers, program will quit. traceAwaitErrors callDisconnectHandlers(peer, reason) if notifyOtherPeer and not peer.transport.closed: var fut = peer.sendDisconnectMsg(reason) yield fut if fut.failed: debug "Failed to deliver disconnect message", peer proc waitAndClose(peer: Peer, time: Duration) {.async.} = await sleepAsync(time) await peer.transport.closeWait() # Give the peer a chance to disconnect traceAsyncErrors peer.waitAndClose(2.seconds) elif not peer.transport.closed: peer.transport.close() logDisconnectedPeer peer peer.connectionState = Disconnected removePeer(peer.network, peer) proc validatePubKeyInHello(msg: devp2p.hello, pubKey: PublicKey): bool = var pk: PublicKey recoverPublicKey(msg.nodeId, pk) == EthKeysStatus.Success and pk == pubKey proc checkUselessPeer(peer: Peer) {.inline.} = if peer.dispatcher.numProtocols == 0: # XXX: Send disconnect + UselessPeer raise newException(UselessPeerError, "Useless peer") proc initPeerState*(peer: Peer, capabilities: openarray[Capability]) = peer.dispatcher = getDispatcher(peer.network, capabilities) checkUselessPeer(peer) # The dispatcher has determined our message ID sequence. # For each message ID, we allocate a potential slot for # tracking responses to requests. # (yes, some of the slots won't be used). peer.outstandingRequests.newSeq(peer.dispatcher.messages.len) for d in mitems(peer.outstandingRequests): d = initDeque[OutstandingRequest]() # Similarly, we need a bit of book-keeping data to keep track # of the potentially concurrent calls to `nextMsg`. peer.awaitedMessages.newSeq(peer.dispatcher.messages.len) peer.lastReqId = 0 peer.initProtocolStates peer.dispatcher.activeProtocols proc postHelloSteps(peer: Peer, h: devp2p.hello) {.async.} = initPeerState(peer, h.capabilities) # Please note that the ordering of operations here is important! # # We must first start all handshake procedures and give them a # chance to send any initial packages they might require over # the network and to yield on their `nextMsg` waits. # var subProtocolsHandshakes = newSeqOfCap[Future[void]](allProtocols.len) for protocol in peer.dispatcher.activeProtocols: if protocol.handshake != nil: subProtocolsHandshakes.add((protocol.handshake)(peer)) # The `dispatchMesssages` loop must be started after this. # Otherwise, we risk that some of the handshake packets sent by # the other peer may arrrive too early and be processed before # the handshake code got a change to wait for them. # var messageProcessingLoop = peer.dispatchMessages() messageProcessingLoop.callback = proc(p: pointer) {.gcsafe.} = if messageProcessingLoop.failed: debug "Ending dispatchMessages loop", peer, err = messageProcessingLoop.error.msg traceAsyncErrors peer.disconnect(ClientQuitting) # The handshake may involve multiple async steps, so we wait # here for all of them to finish. # await all(subProtocolsHandshakes) # This is needed as a peer might have already disconnected. In this case # we need to raise so that rlpxConnect/rlpxAccept fails. # Disconnect is done only to run the disconnect handlers. TODO: improve this # also TODO: Should we discern the type of error? if messageProcessingLoop.finished: await peer.disconnectAndRaise(ClientQuitting, "messageProcessingLoop ended while connecting") peer.connectionState = Connected template `^`(arr): auto = # passes a stack array with a matching `arrLen` # variable as an open array arr.toOpenArray(0, `arr Len` - 1) proc check(status: AuthStatus) = if status != AuthStatus.Success: raise newException(CatchableError, "Error: " & $status) proc initSecretState(hs: var Handshake, authMsg, ackMsg: openarray[byte], p: Peer) = var secrets: ConnectionSecret check hs.getSecrets(authMsg, ackMsg, secrets) initSecretState(secrets, p.secretsState) burnMem(secrets) template checkSnappySupport(node: EthereumNode, handshake: Handshake, peer: Peer) = when useSnappy: peer.snappyEnabled = node.protocolVersion >= devp2pSnappyVersion.uint and handshake.version >= devp2pSnappyVersion.uint template getVersion(handshake: Handshake): uint = when useSnappy: handshake.version else: devp2pVersion template baseProtocolVersion(node: EthereumNode): untyped = when useSnappy: node.protocolVersion else: devp2pVersion template baseProtocolVersion(peer: Peer): uint = when useSnappy: if peer.snappyEnabled: devp2pSnappyVersion else: devp2pVersion else: devp2pVersion proc rlpxConnect*(node: EthereumNode, remote: Node): Future[Peer] {.async.} = initTracing(devp2pInfo, node.protocols) new result result.network = node result.remote = remote let ta = initTAddress(remote.node.address.ip, remote.node.address.tcpPort) var ok = false try: result.transport = await connect(ta) var handshake = newHandshake({Initiator, EIP8}, int(node.baseProtocolVersion)) handshake.host = node.keys var authMsg: array[AuthMessageMaxEIP8, byte] var authMsgLen = 0 check authMessage(handshake, remote.node.pubkey, authMsg, authMsgLen) var res = await result.transport.write(addr authMsg[0], authMsgLen) if res != authMsgLen: raisePeerDisconnected("Unexpected disconnect while authenticating", TcpError) let initialSize = handshake.expectedLength var ackMsg = newSeqOfCap[byte](1024) ackMsg.setLen(initialSize) await result.transport.readExactly(addr ackMsg[0], len(ackMsg)) var ret = handshake.decodeAckMessage(ackMsg) if ret == AuthStatus.IncompleteError: ackMsg.setLen(handshake.expectedLength) await result.transport.readExactly(addr ackMsg[initialSize], len(ackMsg) - initialSize) ret = handshake.decodeAckMessage(ackMsg) check ret node.checkSnappySupport(handshake, result) initSecretState(handshake, ^authMsg, ackMsg, result) # if handshake.remoteHPubkey != remote.node.pubKey: # raise newException(Exception, "Remote pubkey is wrong") logConnectedPeer result var sendHelloFut = result.hello( handshake.getVersion(), node.clientId, node.capabilities, uint(node.address.tcpPort), node.keys.pubkey.getRaw()) var response = await result.handshakeImpl( sendHelloFut, result.waitSingleMsg(devp2p.hello), 10.seconds) if not validatePubKeyInHello(response, remote.node.pubKey): warn "Remote nodeId is not its public key" # XXX: Do we care? await postHelloSteps(result, response) ok = true except PeerDisconnected as e: if e.reason == AlreadyConnected or e.reason == TooManyPeers: trace "Disconnect during rlpxAccept", reason = e.reason else: debug "Unexpected disconnect during rlpxAccept", reason = e.reason except TransportIncompleteError: trace "Connection dropped in rlpxConnect", remote except UselessPeerError: trace "Disconnecting useless peer", peer = remote except RlpTypeMismatch: # Some peers report capabilities with names longer than 3 chars. We ignore # those for now. Maybe we should allow this though. debug "Rlp error in rlpxConnect" except TransportOsError: trace "TransportOsError", err = getCurrentExceptionMsg() except CatchableError: error "Unexpected exception in rlpxConnect", remote, exc = getCurrentException().name, err = getCurrentExceptionMsg() if not ok: if not isNil(result.transport): result.transport.close() result = nil proc rlpxAccept*(node: EthereumNode, transport: StreamTransport): Future[Peer] {.async.} = initTracing(devp2pInfo, node.protocols) new result result.transport = transport result.network = node var handshake = newHandshake({auth.Responder}) handshake.host = node.keys var ok = false try: let initialSize = handshake.expectedLength var authMsg = newSeqOfCap[byte](1024) authMsg.setLen(initialSize) await transport.readExactly(addr authMsg[0], len(authMsg)) var ret = handshake.decodeAuthMessage(authMsg) if ret == AuthStatus.IncompleteError: # Eip8 auth message is likely authMsg.setLen(handshake.expectedLength) await transport.readExactly(addr authMsg[initialSize], len(authMsg) - initialSize) ret = handshake.decodeAuthMessage(authMsg) check ret node.checkSnappySupport(handshake, result) handshake.version = uint8(result.baseProtocolVersion) var ackMsg: array[AckMessageMaxEIP8, byte] var ackMsgLen: int check handshake.ackMessage(ackMsg, ackMsgLen) var res = await transport.write(addr ackMsg[0], ackMsgLen) if res != ackMsgLen: raisePeerDisconnected("Unexpected disconnect while authenticating", TcpError) initSecretState(handshake, authMsg, ^ackMsg, result) let listenPort = transport.localAddress().port logAcceptedPeer result var sendHelloFut = result.hello( result.baseProtocolVersion, node.clientId, node.capabilities, listenPort.uint, node.keys.pubkey.getRaw()) var response = await result.handshakeImpl( sendHelloFut, result.waitSingleMsg(devp2p.hello), 10.seconds) if not validatePubKeyInHello(response, handshake.remoteHPubkey): warn "A Remote nodeId is not its public key" # XXX: Do we care? let remote = transport.remoteAddress() let address = Address(ip: remote.address, tcpPort: remote.port, udpPort: remote.port) result.remote = newNode(initEnode(handshake.remoteHPubkey, address)) # In case there is an outgoing connection started with this peer we give # precedence to that one and we disconnect here with `AlreadyConnected` if result.remote in node.peerPool.connectedNodes or result.remote in node.peerPool.connectingNodes: trace "Duplicate connection in rlpxAccept" raisePeerDisconnected("Peer already connecting or connected", AlreadyConnected) node.peerPool.connectingNodes.incl(result.remote) await postHelloSteps(result, response) ok = true except PeerDisconnected as e: if e.reason == AlreadyConnected or e.reason == TooManyPeers: trace "Disconnect during rlpxAccept", reason = e.reason else: debug "Unexpected disconnect during rlpxAccept", reason = e.reason except TransportIncompleteError: trace "Connection dropped in rlpxAccept", remote = result.remote except UselessPeerError: trace "Disconnecting useless peer", peer = result.remote except RlpTypeMismatch: # Some peers report capabilities with names longer than 3 chars. We ignore # those for now. Maybe we should allow this though. debug "Rlp error in rlpxAccept" except TransportOsError: trace "TransportOsError", err = getCurrentExceptionMsg() except CatchableError: error "Unexpected exception in rlpxAccept", exc = getCurrentException().name, err = getCurrentExceptionMsg() if not ok: if not isNil(result.transport): result.transport.close() result = nil when isMainModule: when false: # The assignments below can be used to investigate if the RLPx procs # are considered GcSafe. The short answer is that they aren't, because # they dispatch into user code that might use the GC. type GcSafeDispatchMsg = proc (peer: Peer, msgId: int, msgData: var Rlp) GcSafeRecvMsg = proc (peer: Peer): Future[tuple[msgId: int, msgData: Rlp]] {.gcsafe.} GcSafeAccept = proc (transport: StreamTransport, myKeys: KeyPair): Future[Peer] {.gcsafe.} var dispatchMsgPtr = invokeThunk recvMsgPtr: GcSafeRecvMsg = recvMsg acceptPtr: GcSafeAccept = rlpxAccept