Merge the contents of backends_common in libp2p_backend

This commit is contained in:
Zahary Karadjov 2020-03-22 22:35:49 +02:00 committed by zah
parent 1752e1c2b6
commit 8300cee131
1 changed files with 401 additions and 2 deletions

View File

@ -1,7 +1,7 @@
import
algorithm, typetraits, net as stdNet,
stew/[varints,base58], stew/shims/[macros, tables], chronos, chronicles,
stint, faststreams/output_stream, serialization,
stint, faststreams/output_stream, serialization, metrics,
json_serialization/std/[net, options],
eth/[keys, async_utils], eth/p2p/[enode, p2p_protocol_dsl],
eth/p2p/discoveryv5/[enr, node],
@ -23,6 +23,7 @@ export
p2pProtocol, libp2p_json_serialization, ssz
type
Bytes = seq[byte]
P2PStream = Connection
# TODO Is this really needed?
@ -82,6 +83,11 @@ type
ProtocolInfo* = ptr ProtocolInfoObj
ResponseCode* = enum
Success
InvalidRequest
ServerError
PeerStateInitializer* = proc(peer: Peer): RootRef {.gcsafe.}
NetworkStateInitializer* = proc(network: EthereumNode): RootRef {.gcsafe.}
HandshakeStep* = proc(peer: Peer, stream: P2PStream): Future[void] {.gcsafe.}
@ -103,6 +109,28 @@ type
const
TCP = net.Protocol.IPPROTO_TCP
defaultIncomingReqTimeout = 5000
HandshakeTimeout = FaultOrError
# Spec constants
# https://github.com/ethereum/eth2.0-specs/blob/dev/specs/networking/p2p-interface.md#eth-20-network-interaction-domains
REQ_RESP_MAX_SIZE* = 1 * 1024 * 1024 # bytes
GOSSIP_MAX_SIZE* = 1 * 1024 * 1024 # bytes
TTFB_TIMEOUT* = 5.seconds
RESP_TIMEOUT* = 10.seconds
readTimeoutErrorMsg = "Exceeded read timeout for a request"
logScope:
topics = "libp2p"
declarePublicGauge libp2p_successful_dials,
"Number of successfully dialed peers"
declarePublicGauge libp2p_peers,
"Number of active libp2p peers"
template libp2pProtocol*(name: string, version: int) {.pragma.}
template `$`*(peer: Peer): string = id(peer.info)
chronicles.formatIt(Peer): $it
@ -165,7 +193,378 @@ proc handleIncomingPeer*(peer: Peer)
include eth/p2p/p2p_backends_helpers
include eth/p2p/p2p_tracing
include libp2p_backends_common
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":
let protoName = $(pragma[1])
let protoVer = $(pragma[2].intVal)
return newLit("/eth2/beacon_chain/req/" & protoName & "/" & protoVer & "/ssz")
return newLit("")
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)
proc readChunk(stream: P2PStream,
MsgType: type,
withResponseCode: bool,
deadline: Future[void]): Future[Option[MsgType]] {.gcsafe.}
proc readSizePrefix(stream: P2PStream,
deadline: Future[void]): Future[int] {.async.} =
trace "about to read msg size prefix"
var parser: VarintParser[uint64, ProtoBuf]
while true:
var nextByte: byte
var readNextByte = stream.readExactly(addr nextByte, 1)
await readNextByte or deadline
if not readNextByte.finished:
trace "size prefix byte not received in time"
return -1
case parser.feedByte(nextByte)
of Done:
let res = parser.getResult
if res > uint64(REQ_RESP_MAX_SIZE):
trace "size prefix outside of range", res
return -1
else:
trace "got size prefix", res
return int(res)
of Overflow:
trace "size prefix overflow"
return -1
of Incomplete:
continue
proc readMsgBytes(stream: P2PStream,
withResponseCode: bool,
deadline: Future[void]): Future[Bytes] {.async.} =
trace "about to read message bytes", withResponseCode
try:
if withResponseCode:
var responseCode: byte
trace "about to read response code"
var readResponseCode = stream.readExactly(addr responseCode, 1)
await readResponseCode or deadline
if not readResponseCode.finished:
trace "response code not received in time"
return
if responseCode > ResponseCode.high.byte:
trace "invalid response code", responseCode
return
logScope: responseCode = ResponseCode(responseCode)
trace "got response code"
case ResponseCode(responseCode)
of InvalidRequest, ServerError:
let responseErrMsg = await readChunk(stream, string, false, deadline)
debug "P2P request resulted in error", responseErrMsg
return
of Success:
# The response is OK, the execution continues below
discard
var sizePrefix = await readSizePrefix(stream, deadline)
trace "got msg size prefix", sizePrefix
if sizePrefix == -1:
debug "Failed to read an incoming message size prefix", peer = stream.peer
return
if sizePrefix == 0:
debug "Received SSZ with zero size", peer = stream.peer
return
trace "about to read msg bytes", len = sizePrefix
var msgBytes = newSeq[byte](sizePrefix)
var readBody = stream.readExactly(addr msgBytes[0], sizePrefix)
await readBody or deadline
if not readBody.finished:
trace "msg bytes not received in time"
return
trace "got message bytes", len = sizePrefix
return msgBytes
except TransportIncompleteError:
return @[]
proc readChunk(stream: P2PStream,
MsgType: type,
withResponseCode: bool,
deadline: Future[void]): Future[Option[MsgType]] {.gcsafe, async.} =
var msgBytes = await stream.readMsgBytes(withResponseCode, deadline)
try:
if msgBytes.len > 0:
return some SSZ.decode(msgBytes, MsgType)
except SerializationError as err:
debug "Failed to decode a network message",
msgBytes, errMsg = err.formatMsg("<msg>")
return
proc readResponse(
stream: P2PStream,
MsgType: type,
deadline: Future[void]): Future[Option[MsgType]] {.gcsafe, async.} =
when MsgType is seq:
type E = ElemType(MsgType)
var results: MsgType
while true:
let nextRes = await readChunk(stream, E, true, deadline)
if nextRes.isNone: break
results.add nextRes.get
if results.len > 0:
return some(results)
else:
return await readChunk(stream, MsgType, true, deadline)
proc encodeErrorMsg(responseCode: ResponseCode, errMsg: string): Bytes =
var s = init OutputStream
s.append byte(responseCode)
s.appendVarint errMsg.len
s.appendValue SSZ, errMsg
s.getOutput
proc sendErrorResponse(peer: Peer,
stream: P2PStream,
err: ref SerializationError,
msgName: string,
msgBytes: Bytes) {.async.} =
debug "Received an invalid request",
peer, msgName, msgBytes, errMsg = err.formatMsg("<msg>")
let responseBytes = encodeErrorMsg(InvalidRequest, err.formatMsg("msg"))
await stream.writeAllBytes(responseBytes)
await stream.close()
proc sendErrorResponse(peer: Peer,
stream: P2PStream,
responseCode: ResponseCode,
errMsg: string) {.async.} =
debug "Error processing request", peer, responseCode, errMsg
let responseBytes = encodeErrorMsg(ServerError, errMsg)
await stream.writeAllBytes(responseBytes)
await stream.close()
proc sendNotificationMsg(peer: Peer, protocolId: string, requestBytes: Bytes) {.async} =
var deadline = sleepAsync RESP_TIMEOUT
var streamFut = peer.network.openStream(peer, protocolId)
await streamFut or deadline
if not streamFut.finished:
# TODO: we are returning here because the deadline passed, but
# the stream can still be opened eventually a bit later. Who is
# going to close it then?
raise newException(TransmissionError, "Failed to open LibP2P stream")
let stream = streamFut.read
defer:
await safeClose(stream)
var s = init OutputStream
s.appendVarint requestBytes.len.uint64
s.append requestBytes
let bytes = s.getOutput
await stream.writeAllBytes(bytes)
# TODO There is too much duplication in the responder functions, but
# I hope to reduce this when I increse the reliance on output streams.
proc sendResponseChunkBytes(responder: UntypedResponder, payload: Bytes) {.async.} =
var s = init OutputStream
s.append byte(Success)
s.appendVarint payload.len.uint64
s.append payload
let bytes = s.getOutput
await responder.stream.writeAllBytes(bytes)
proc sendResponseChunkObj(responder: UntypedResponder, val: auto) {.async.} =
var s = init OutputStream
s.append byte(Success)
s.appendValue SSZ, sizePrefixed(val)
let bytes = s.getOutput
await responder.stream.writeAllBytes(bytes)
proc sendResponseChunks[T](responder: UntypedResponder, chunks: seq[T]) {.async.} =
var s = init OutputStream
for chunk in chunks:
s.append byte(Success)
s.appendValue SSZ, sizePrefixed(chunk)
let bytes = s.getOutput
await responder.stream.writeAllBytes(bytes)
proc makeEth2Request(peer: Peer, protocolId: string, requestBytes: Bytes,
ResponseMsg: type,
timeout: Duration): Future[Option[ResponseMsg]] {.gcsafe, async.} =
var deadline = sleepAsync timeout
# Open a new LibP2P stream
var streamFut = peer.network.openStream(peer, protocolId)
await streamFut or deadline
if not streamFut.finished:
# TODO: we are returning here because the deadline passed, but
# the stream can still be opened eventually a bit later. Who is
# going to close it then?
return none(ResponseMsg)
let stream = streamFut.read
defer:
await safeClose(stream)
# Send the request
var s = init OutputStream
s.appendVarint requestBytes.len.uint64
s.append requestBytes
let bytes = s.getOutput
await stream.writeAllBytes(bytes)
# Read the response
return await stream.readResponse(ResponseMsg, deadline)
proc init*[MsgType](T: type Responder[MsgType],
peer: Peer, stream: P2PStream): T =
T(UntypedResponder(peer: peer, stream: stream))
template write*[M](r: var Responder[M], val: auto): auto =
mixin send
type Msg = M
type MsgRec = RecType(Msg)
when MsgRec is seq|openarray:
type E = ElemType(MsgRec)
when val is E:
sendResponseChunkObj(UntypedResponder(r), val)
elif val is MsgRec:
sendResponseChunks(UntypedResponder(r), val)
else:
{.fatal: "Unepected message type".}
else:
send(r, val)
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)
template initializeConnection*(peer: Peer): auto =
performProtocolHandshakes(peer)
proc initProtocol(name: string,
peerInit: PeerStateInitializer,
networkInit: NetworkStateInitializer): ProtocolInfoObj =
result.name = name
result.messages = @[]
result.peerStateInitializer = peerInit
result.networkStateInitializer = networkInit
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 setEventHandlers(p: ProtocolInfo,
handshake: HandshakeStep,
disconnectHandler: DisconnectionHandler) =
p.handshake = handshake
p.disconnectHandler = disconnectHandler
proc implementSendProcBody(sendProc: SendProc) =
let
msg = sendProc.msg
UntypedResponder = bindSym "UntypedResponder"
await = ident "await"
proc sendCallGenerator(peer, bytes: NimNode): NimNode =
if msg.kind != msgResponse:
let msgProto = getRequestProtoName(msg.procDef)
case msg.kind
of msgRequest:
let
timeout = msg.timeoutParam[0]
ResponseRecord = msg.response.recName
quote:
makeEth2Request(`peer`, `msgProto`, `bytes`,
`ResponseRecord`, `timeout`)
else:
quote: sendNotificationMsg(`peer`, `msgProto`, `bytes`)
else:
quote: sendResponseChunkBytes(`UntypedResponder`(`peer`), `bytes`)
sendProc.useStandardBody(nil, nil, sendCallGenerator)
proc handleIncomingStream(network: Eth2Node, stream: P2PStream,
MsgType, Format: distinct type) {.async, gcsafe.} =
mixin callUserHandler, RecType
const msgName = typetraits.name(MsgType)
## Uncomment this to enable tracing on all incoming requests
## You can include `msgNameLit` in the condition to select
## more specific requests:
# when chronicles.runtimeFilteringEnabled:
# setLogLevel(LogLevel.TRACE)
# defer: setLogLevel(LogLevel.DEBUG)
# trace "incoming " & `msgNameLit` & " stream"
let peer = peerFromStream(network, stream)
handleIncomingPeer(peer)
defer:
await safeClose(stream)
let
deadline = sleepAsync RESP_TIMEOUT
msgBytes = await readMsgBytes(stream, false, deadline)
if msgBytes.len == 0:
await sendErrorResponse(peer, stream, ServerError, readTimeoutErrorMsg)
return
type MsgRec = RecType(MsgType)
var msg: MsgRec
try:
msg = decode(Format, msgBytes, MsgRec)
except SerializationError as err:
await sendErrorResponse(peer, stream, err, msgName, msgBytes)
return
except Exception as err:
# TODO. This is temporary code that should be removed after interop.
# It can be enabled only in certain diagnostic builds where it should
# re-raise the exception.
debug "Crash during serialization", inputBytes = toHex(msgBytes), msgName
await sendErrorResponse(peer, stream, ServerError, err.msg)
raise err
try:
logReceivedMsg(peer, MsgType(msg))
await callUserHandler(peer, stream, msg)
except CatchableError as err:
await sendErrorResponse(peer, stream, ServerError, err.msg)
proc handleOutgoingPeer*(peer: Peer): Future[void] {.async.} =
let network = peer.network