fix: stun and dtls close (#22)

* fix: stun & dtls close

* chore: change the test names & variable names

* fix: add isClosed to DtlsConn

* feat: remove `closeEvent`/`join`/`cleanup` and replace those by `onClose` sequence of proc to be executed on close

tests/testdtls.nim

@@ -81,3 +81,40 @@ suite "DTLS":
     await allFutures(dtls1.stop(), dtls2.stop(), dtls3.stop())
     await allFutures(stun1.stop(), stun2.stop(), stun3.stop())
     await allFutures(udp1.close(), udp2.close(), udp3.close())
+
+  asyncTest "Two DTLS nodes connecting to each other, closing the created connections then re-connect the nodes":
+    # Related to https://github.com/vacp2p/nim-webrtc/pull/22
+    let
+      localAddr1 = initTAddress("127.0.0.1:4444")
+      localAddr2 = initTAddress("127.0.0.1:5555")
+      udp1 = UdpTransport.new(localAddr1)
+      udp2 = UdpTransport.new(localAddr2)
+      stun1 = Stun.new(udp1)
+      stun2 = Stun.new(udp2)
+      dtls1 = Dtls.new(stun1)
+      dtls2 = Dtls.new(stun2)
+    var
+      serverConnFut = dtls1.accept()
+      clientConn = await dtls2.connect(localAddr1)
+      serverConn = await serverConnFut
+
+    await serverConn.write(@[1'u8, 2, 3, 4])
+    await clientConn.write(@[5'u8, 6, 7, 8])
+    check (await serverConn.read()) == @[5'u8, 6, 7, 8]
+    check (await clientConn.read()) == @[1'u8, 2, 3, 4]
+    await allFutures(serverConn.close(), clientConn.close())
+    check serverConn.isClosed() and clientConn.isClosed()
+
+    serverConnFut = dtls1.accept()
+    clientConn = await dtls2.connect(localAddr1)
+    serverConn = await serverConnFut
+
+    await serverConn.write(@[5'u8, 6, 7, 8])
+    await clientConn.write(@[1'u8, 2, 3, 4])
+    check (await serverConn.read()) == @[1'u8, 2, 3, 4]
+    check (await clientConn.read()) == @[5'u8, 6, 7, 8]
+
+    await allFutures(serverConn.close(), clientConn.close())
+    await allFutures(dtls1.stop(), dtls2.stop())
+    await allFutures(stun1.stop(), stun2.stop())
+    await allFutures(udp1.close(), udp2.close())

webrtc/dtls/dtls_connection.nim

@@ -21,6 +21,8 @@ logScope:
 const DtlsConnTracker* = "webrtc.dtls.conn"
 
 type
+  DtlsConnOnClose* = proc() {.raises: [], gcsafe.}
+
   MbedTLSCtx = object
     ssl: mbedtls_ssl_context
     config: mbedtls_ssl_config
@@ -34,7 +36,7 @@ type
   DtlsConn* = ref object
     # DtlsConn is a Dtls connection receiving and sending data using
     # the underlying Stun Connection
-    conn*: StunConn # The wrapper protocol Stun Connection
+    conn: StunConn # The wrapper protocol Stun Connection
     raddr: TransportAddress # Remote address
     dataRecv: seq[byte] # data received which will be read by SCTP
     dataToSend: seq[byte]
@@ -43,7 +45,7 @@ type
 
     # Close connection management
     closed: bool
-    closeEvent: AsyncEvent
+    onClose: seq[DtlsConnOnClose]
 
     # Local and Remote certificate, needed by wrapped protocol DataChannel
     # and by libp2p
@@ -53,6 +55,9 @@ type
     # Mbed-TLS contexts
     ctx: MbedTLSCtx
 
+proc isClosed*(self: DtlsConn): bool =
+  return self.closed
+
 proc getRemoteCertificateCallback(
     ctx: pointer, pcert: ptr mbedtls_x509_crt, state: cint, pflags: ptr uint32
 ): cint {.cdecl.} =
@@ -100,7 +105,6 @@ proc new*(T: type DtlsConn, conn: StunConn): T =
   var self = T(conn: conn)
   self.raddr = conn.raddr
   self.closed = false
-  self.closeEvent = newAsyncEvent()
   return self
 
 proc dtlsConnInit(self: DtlsConn) =
@@ -160,10 +164,10 @@ proc connectInit*(self: DtlsConn, ctr_drbg: mbedtls_ctr_drbg_context) =
   except MbedTLSError as exc:
     raise newException(WebRtcError, "DTLS - Connect initialization: " & exc.msg, exc)
 
-proc join*(self: DtlsConn) {.async: (raises: [CancelledError]).} =
-  ## Wait for the Dtls Connection to be closed
+proc addOnClose*(self: DtlsConn, onCloseProc: DtlsConnOnClose) =
+  ## Adds a proc to be called when DtlsConn is closed
   ##
-  await self.closeEvent.wait()
+  self.onClose.add(onCloseProc)
 
 proc dtlsHandshake*(
     self: DtlsConn, isServer: bool
@@ -217,7 +221,10 @@ proc close*(self: DtlsConn) {.async: (raises: [CancelledError, WebRtcError]).} =
     await self.conn.write(self.dataToSend)
   self.dataToSend = @[]
   untrackCounter(DtlsConnTracker)
-  self.closeEvent.fire()
+  await self.conn.close()
+  for onCloseProc in self.onClose:
+    onCloseProc()
+  self.onClose = @[]
 
 proc write*(
     self: DtlsConn, msg: seq[byte]

webrtc/dtls/dtls_transport.nim

@@ -28,12 +28,8 @@ logScope:
 const DtlsTransportTracker* = "webrtc.dtls.transport"
 
 type
-  DtlsConnAndCleanup = object
-    connection: DtlsConn
-    cleanup: Future[void].Raising([])
-
   Dtls* = ref object of RootObj
-    connections: Table[TransportAddress, DtlsConnAndCleanup]
+    connections: Table[TransportAddress, DtlsConn]
     transport: Stun
     laddr: TransportAddress
     started: bool
@@ -46,7 +42,7 @@ type
 
 proc new*(T: type Dtls, transport: Stun): T =
   var self = T(
-    connections: initTable[TransportAddress, DtlsConnAndCleanup](),
+    connections: initTable[TransportAddress, DtlsConn](),
     transport: transport,
     laddr: transport.laddr,
     started: true,
@@ -72,10 +68,8 @@ proc stop*(self: Dtls) {.async: (raises: [CancelledError]).} =
 
   self.started = false
   let
-    allCloses = toSeq(self.connections.values()).mapIt(it.connection.close())
-    allCleanup = toSeq(self.connections.values()).mapIt(it.cleanup)
+    allCloses = toSeq(self.connections.values()).mapIt(it.close())
   await noCancel allFutures(allCloses)
-  await noCancel allFutures(allCleanup)
   untrackCounter(DtlsTransportTracker)
 
 proc localCertificate*(self: Dtls): seq[byte] =
@@ -85,14 +79,11 @@ proc localCertificate*(self: Dtls): seq[byte] =
 proc localAddress*(self: Dtls): TransportAddress =
   self.laddr
 
-proc cleanupDtlsConn(self: Dtls, conn: DtlsConn) {.async: (raises: []).} =
-  # Waiting for a connection to be closed to remove it from the table
-  try:
-    await conn.join()
-  except CancelledError as exc:
-    discard
-
+proc addConnToTable(self: Dtls, conn: DtlsConn) =
+  proc cleanup() =
     self.connections.del(conn.remoteAddress())
+  self.connections[conn.remoteAddress()] = conn
+  conn.addOnClose(cleanup)
 
 proc accept*(
     self: Dtls
@@ -114,8 +105,7 @@ proc accept*(
           self.ctr_drbg, self.serverPrivKey, self.serverCert, self.localCert
         )
         await res.dtlsHandshake(true)
-        self.connections[raddr] =
-          DtlsConnAndCleanup(connection: res, cleanup: self.cleanupDtlsConn(res))
+        self.addConnToTable(res)
         break
       except WebRtcError as exc:
         trace "Handshake fails, try accept another connection", raddr, error = exc.msg
@@ -136,8 +126,7 @@ proc connect*(
 
   try:
     await res.dtlsHandshake(false)
-    self.connections[raddr] =
-      DtlsConnAndCleanup(connection: res, cleanup: self.cleanupDtlsConn(res))
+    self.addConnToTable(res)
   except WebRtcError as exc:
     trace "Handshake fails", raddr, error = exc.msg
     self.connections.del(raddr)

webrtc/stun/stun_connection.nim

@@ -28,6 +28,7 @@ type
   StunUsernameProvider* = proc(): string {.raises: [], gcsafe.}
   StunUsernameChecker* = proc(username: seq[byte]): bool {.raises: [], gcsafe.}
   StunPasswordProvider* = proc(username: seq[byte]): seq[byte] {.raises: [], gcsafe.}
+  StunConnOnClose* = proc() {.raises: [], gcsafe.}
 
   StunConn* = ref object
     udp*: UdpTransport # The wrapper protocol: UDP Transport
@@ -37,8 +38,10 @@ type
     stunMsgs*: AsyncQueue[seq[byte]] # stun messages received and to be
                                      # processed by the stun message handler
     handlesFut*: Future[void] # Stun Message handler
-    closeEvent: AsyncEvent
+
+    # Close connection management
     closed*: bool
+    onClose: seq[StunConnOnClose]
 
     # Is ice-controlling and iceTiebreaker, not fully implemented yet.
     iceControlling: bool
@@ -201,7 +204,6 @@ proc new*(
     laddr: udp.laddr,
     raddr: raddr,
     closed: false,
-    closeEvent: newAsyncEvent(),
     dataRecv: newAsyncQueue[seq[byte]](StunMaxQueuingMessages),
     stunMsgs: newAsyncQueue[seq[byte]](StunMaxQueuingMessages),
     iceControlling: iceControlling,
@@ -215,10 +217,10 @@ proc new*(
   trackCounter(StunConnectionTracker)
   return self
 
-proc join*(self: StunConn) {.async: (raises: [CancelledError]).} =
-  ## Wait for the Stun Connection to be closed
+proc addOnClose*(self: StunConn, onCloseProc: StunConnOnClose) =
+  ## Adds a proc to be called when StunConn is closed
   ##
-  await self.closeEvent.wait()
+  self.onClose.add(onCloseProc)
 
 proc close*(self: StunConn) {.async: (raises: []).} =
   ## Close a Stun Connection
@@ -227,7 +229,9 @@ proc close*(self: StunConn) {.async: (raises: []).} =
     debug "Try to close an already closed StunConn"
     return
   await self.handlesFut.cancelAndWait()
-  self.closeEvent.fire()
+  for onCloseProc in self.onClose:
+    onCloseProc()
+  self.onClose = @[]
   self.closed = true
   untrackCounter(StunConnectionTracker)
 

webrtc/stun/stun_transport.nim

@@ -32,6 +32,12 @@ type
 
     rng: ref HmacDrbgContext
 
+proc addConnToTable(self: Stun, conn: StunConn) =
+  proc cleanup() =
+    self.connections.del(conn.raddr)
+  self.connections[conn.raddr] = conn
+  conn.addOnClose(cleanup)
+
 proc accept*(self: Stun): Future[StunConn] {.async: (raises: [CancelledError]).} =
   ## Accept a Stun Connection
   ##
@@ -53,17 +59,9 @@ proc connect*(
   do:
     let res = StunConn.new(self.udp, raddr, false, self.usernameProvider,
       self.usernameChecker, self.passwordProvider, self.rng)
-    self.connections[raddr] = res
+    self.addConnToTable(res)
     return res
 
-proc cleanupStunConn(self: Stun, conn: StunConn) {.async: (raises: []).} =
-  # Waiting for a connection to be closed to remove it from the table
-  try:
-    await conn.join()
-    self.connections.del(conn.raddr)
-  except CancelledError as exc:
-    warn "Error cleaning up Stun Connection", error=exc.msg
-
 proc stunReadLoop(self: Stun) {.async: (raises: [CancelledError]).} =
   while true:
     let (buf, raddr) = await self.udp.read()
@@ -71,9 +69,8 @@ proc stunReadLoop(self: Stun) {.async: (raises: [CancelledError]).} =
     if not self.connections.hasKey(raddr):
       stunConn = StunConn.new(self.udp, raddr, true, self.usernameProvider,
         self.usernameChecker, self.passwordProvider, self.rng)
-      self.connections[raddr] = stunConn
+      self.addConnToTable(stunConn)
       await self.pendingConn.addLast(stunConn)
-      asyncSpawn self.cleanupStunConn(stunConn)
     else:
       try:
         stunConn = self.connections[raddr]