Fix chronos related deprecated warnings in uTP code part II (#669)

This also makes the uTP SendCallBack not returning a Future any
more as it is not used in sendData anyhow. And in case of uTP
over discv5, discv5 send call is already not async.

This gives quite a noticable throughput benchmark improvement over
with uTP over UDP, and a slightly noticable with uTP over discv5

eth/utp/utp_discv5_protocol.nim

@@ -70,16 +70,13 @@ proc initSendCallback(
     t: protocol.Protocol, subProtocolName: seq[byte]):
     SendCallback[NodeAddress] =
   return (
-    proc (to: NodeAddress, data: seq[byte]): Future[void] =
-      let fut = newFuture[void]()
+    proc (to: NodeAddress, data: seq[byte]){.raises: [], gcsafe.} =
       # hidden assumption here is that nodes already have established discv5
       # session between each other. In our use case this should be true as
       # opening stream is only done after successful OFFER/ACCEPT or
       # FINDCONTENT/CONTENT exchange which forces nodes to establish session
       # between each other.
       discard t.talkReqDirect(to, subProtocolName, data)
-      fut.complete()
-      return fut
   )
 
 proc messageHandler(

eth/utp/utp_protocol.nim

@@ -63,7 +63,7 @@ proc hash(x: UtpSocketKey[TransportAddress]): Hash =
   !$h
 
 proc processDatagram(transp: DatagramTransport, raddr: TransportAddress):
-    Future[void] {.async.} =
+    Future[void] {.async: (raises: []).} =
   let router = getUserData[UtpRouter[TransportAddress]](transp)
   # TODO: should we use `peekMessage()` to avoid allocation?
   let buf = try: transp.getMessage()
@@ -71,12 +71,21 @@ proc processDatagram(transp: DatagramTransport, raddr: TransportAddress):
               trace "Error reading datagram msg: ", error = e.msg
               # This is likely to be local network connection issues.
               return
+  try:
     await processIncomingBytes[TransportAddress](router, buf, raddr)
+  except CancelledError:
+    debug "processIncomingBytes canceled"
 
 proc initSendCallback(t: DatagramTransport): SendCallback[TransportAddress] =
   return (
-    proc (to: TransportAddress, data: seq[byte]): Future[void] =
-      t.sendTo(to, data)
+    proc (
+        to: TransportAddress, data: seq[byte]
+    ) {.raises: [], gcsafe.} =
+      let fut = t.sendTo(to, data)
+      let cb = proc(data: pointer) {.gcsafe.} =
+        if fut.failed:
+          debug "uTP send failed", msg = fut.readError.msg
+      fut.addCallback cb
   )
 
 proc new*(

eth/utp/utp_router.nim

@@ -187,7 +187,9 @@ proc shouldAllowConnection[A](
   else:
     r.allowConnection(r, remoteAddress, connectionId)
 
-proc processPacket[A](r: UtpRouter[A], p: Packet, sender: A) {.async.}=
+proc processPacket[A](
+    r: UtpRouter[A], p: Packet, sender: A
+  ) {.async: (raises: [CancelledError]).}=
   debug "Received packet ",
     sender = sender,
     packetType = p.header.pType
@@ -252,10 +254,11 @@ proc processPacket[A](r: UtpRouter[A], p: Packet, sender: A) {.async.}=
       debug "Received FIN/DATA/ACK on unknown socket, sending reset"
       let rstPacket = resetPacket(
         randUint16(r.rng[]), p.header.connectionId, p.header.seqNr)
-      await r.sendCb(sender, encodePacket(rstPacket))
+      r.sendCb(sender, encodePacket(rstPacket))
 
 proc processIncomingBytes*[A](
-    r: UtpRouter[A], bytes: seq[byte], sender: A) {.async.} =
+    r: UtpRouter[A], bytes: seq[byte], sender: A
+  ) {.async: (raises:[CancelledError]).} =
   if (not r.closed):
     let decoded = decodePacket(bytes)
     if (decoded.isOk()):

eth/utp/utp_socket.nim

@@ -49,7 +49,9 @@ type
 
   # Socket callback to send data to remote peer
   SendCallback*[A] =
-    proc (to: A, data: seq[byte]): Future[void] {.gcsafe, raises: []}
+    proc (
+      to: A, data: seq[byte]
+    ) {.gcsafe, raises: [].}
 
   SocketConfig* = object
     # This is configurable (in contrast to reference impl), as with standard 2
@@ -452,11 +454,8 @@ proc registerOutgoingPacket(socket: UtpSocket, oPacket: OutgoingPacket) =
   inc socket.seqNr
   inc socket.curWindowPackets
 
-proc sendData(socket: UtpSocket, data: seq[byte]): Future[void] {.async.} =
-  try:
-    await socket.send(socket.remoteAddress, data)
-  except CatchableError as e:
-    warn "UTP send failed", msg = e.msg
+proc sendData(socket: UtpSocket, data: seq[byte]) =
+  socket.send(socket.remoteAddress, data)
 
 proc sendPacket(socket: UtpSocket, seqNr: uint16) =
   proc setSend(p: var OutgoingPacket): seq[byte] =
@@ -474,7 +473,7 @@ proc sendPacket(socket: UtpSocket, seqNr: uint16) =
 
     return p.packetBytes
 
-  asyncSpawn socket.sendData(setSend(socket.outBuffer[seqNr]))
+  socket.sendData(setSend(socket.outBuffer[seqNr]))
 
 proc resetSendTimeout(socket: UtpSocket) =
   socket.retransmitTimeout = socket.rto
@@ -1112,7 +1111,7 @@ proc sendAck(socket: UtpSocket) =
     pkAckNr = ackPacket.header.ackNr,
     gotEACK = ackPacket.eack.isSome()
 
-  asyncSpawn socket.sendData(encodePacket(ackPacket))
+  socket.sendData(encodePacket(ackPacket))
 
 
 proc tryfinalizeConnection(socket: UtpSocket, p: Packet) =
@@ -1568,7 +1567,9 @@ proc processPacketInternal(socket: UtpSocket, p: Packet) =
           # will be generated
           socket.sendAck()
 
-proc processPacket*(socket: UtpSocket, p: Packet): Future[void] =
+proc processPacket*(
+    socket: UtpSocket, p: Packet
+  ): Future[void] {.async: (raw: true, raises: [CancelledError]).} =
   socket.eventQueue.put(SocketEvent(kind: NewPacket, packet: p))
 
 template shiftBuffer(t, c: untyped) =
@@ -2081,5 +2082,5 @@ proc startOutgoingSocket*(socket: UtpSocket): Future[void] =
   socket.registerOutgoingPacket(outgoingPacket)
   socket.startEventLoop()
   socket.startTimeoutLoop()
-  asyncSpawn socket.sendData(outgoingPacket.packetBytes)
+  socket.sendData(outgoingPacket.packetBytes)
   return socket.connectionFuture

tests/utp/test_protocol_integration.nim

@@ -54,16 +54,29 @@ proc getServerSocket(
 procSuite "uTP over UDP protocol with loss and delays":
   let rng = newRng()
 
+  proc simulatedSend(
+      d: DatagramTransport, to: TransportAddress, data: seq[byte],
+      maxDelay: int, packetDropRate: int
+  ) {.async: (raises: []).} =
+    let i = rand(rng[], 99)
+    if i >= packetDropRate:
+      let delay = milliseconds(rand(rng[], maxDelay))
+      try:
+        await sleepAsync(delay)
+        await d.sendTo(to, data)
+      except TransportError:
+        # ignore
+        return
+      except CancelledError:
+        # ignore
+        return
+
   proc sendBuilder(maxDelay: int, packetDropRate: int): SendCallbackBuilder =
     return (
       proc (d: DatagramTransport): SendCallback[TransportAddress] =
         return (
-          proc (to: TransportAddress, data: seq[byte]): Future[void] {.async.} =
-            let i = rand(rng[], 99)
-            if i >= packetDropRate:
-              let delay = milliseconds(rand(rng[], maxDelay))
-              await sleepAsync(delay)
-              await d.sendTo(to, data)
+          proc (to: TransportAddress, data: seq[byte]) =
+            asyncSpawn simulatedSend(d, to, data, maxDelay, packetDropRate)
         )
     )
 

tests/utp/test_utils.nim

@@ -107,7 +107,12 @@ proc generateDataPackets*(
 
 proc initTestSnd*(q: AsyncQueue[Packet]): SendCallback[TransportAddress]=
   return (
-    proc (to: TransportAddress, bytes: seq[byte]): Future[void] =
+    proc (
+        to: TransportAddress, bytes: seq[byte]
+    ) {.raises: [], gcsafe.} =
       let p = decodePacket(bytes).get()
-      q.addLast(p)
+      try:
+        q.addLastNoWait(p)
+      except AsyncQueueFullError:
+        raiseAssert "Should not occur as unlimited queue"
   )

tests/utp/test_utp_router.nim

@@ -37,16 +37,17 @@ procSuite "uTP router unit":
         serverSockets.addLast(client)
     )
 
-  proc testSend(to: int, bytes: seq[byte]): Future[void] =
-    let f = newFuture[void]()
-    f.complete()
-    f
+  proc testSend(to: int, bytes: seq[byte]) =
+    discard
 
   proc initTestSnd(q: AsyncQueue[(Packet, int)]): SendCallback[int]=
     return (
-      proc (to: int, bytes: seq[byte]): Future[void] =
+      proc (to: int, bytes: seq[byte]) {.raises: [], gcsafe.} =
         let p = decodePacket(bytes).get()
-        q.addLast((p, to))
+        try:
+          q.addLastNoWait((p, to))
+        except AsyncQueueFullError:
+          raiseAssert "Should not occur as unlimited queue"
     )
 
   template connectOutgoing(
@@ -359,14 +360,14 @@ procSuite "uTP router unit":
     check:
       router.len() == 0
 
-  asyncTest "Router should clear all resources and handle error while sending syn packet":
+  asyncTest "Router should clear all resources and handle error when sending syn packet fails":
     let q = newAsyncQueue[UtpSocket[int]]()
     let router = UtpRouter[int].new(registerIncomingSocketCallback(q), SocketConfig.init(milliseconds(500)), rng)
     router.sendCb =
-      proc (to: int, data: seq[byte]): Future[void] =
-        let f = newFuture[void]()
-        f.fail(newException(TestError, "failed"))
-        return f
+      proc (to: int, data: seq[byte]) =
+        # Can just discard here not to send anything as the send callback does
+        # not forward errors anyhow
+        discard
 
     let connectResult = await router.connectTo(testSender2)