[udp] forbid udp duplicate open (#6626)

include/openthread/instance.h

@@ -53,7 +53,7 @@ extern "C" {
  * @note This number versions both OpenThread platform and user APIs.
  *
  */
-#define OPENTHREAD_API_VERSION (128)
+#define OPENTHREAD_API_VERSION (129)
 
 /**
  * @addtogroup api-instance

include/openthread/udp.h

@@ -160,6 +160,17 @@ otMessage *otUdpNewMessage(otInstance *aInstance, const otMessageSettings *aSett
  */
 otError otUdpOpen(otInstance *aInstance, otUdpSocket *aSocket, otUdpReceive aCallback, void *aContext);
 
+/**
+ * Check if a UDP socket is open.
+ *
+ * @param[in]  aInstance  A pointer to an OpenThread instance.
+ * @param[in]  aSocket    A pointer to a UDP socket structure.
+ *
+ * @returns Whether the UDP socket is open.
+ *
+ */
+bool otUdpIsOpen(otInstance *aInstance, const otUdpSocket *aSocket);
+
 /**
  * Close a UDP/IPv6 socket.
  *

src/cli/cli_udp.cpp

@@ -109,7 +109,13 @@ otError UdpExample::ProcessOpen(uint8_t aArgsLength, Arg aArgs[])
     OT_UNUSED_VARIABLE(aArgsLength);
     OT_UNUSED_VARIABLE(aArgs);
 
-    return otUdpOpen(mInterpreter.mInstance, &mSocket, HandleUdpReceive, this);
+    otError error;
+
+    VerifyOrExit(!otUdpIsOpen(mInterpreter.mInstance, &mSocket), error = OT_ERROR_ALREADY);
+    error = otUdpOpen(mInterpreter.mInstance, &mSocket, HandleUdpReceive, this);
+
+exit:
+    return error;
 }
 
 otError UdpExample::ProcessSend(uint8_t aArgsLength, Arg aArgs[])

src/core/api/udp_api.cpp

@@ -56,6 +56,13 @@ otError otUdpOpen(otInstance *aInstance, otUdpSocket *aSocket, otUdpReceive aCal
     return instance.Get<Ip6::Udp>().Open(*static_cast<Ip6::Udp::SocketHandle *>(aSocket), aCallback, aContext);
 }
 
+bool otUdpIsOpen(otInstance *aInstance, const otUdpSocket *aSocket)
+{
+    Instance &instance = *static_cast<Instance *>(aInstance);
+
+    return instance.Get<Ip6::Udp>().IsOpen(*static_cast<const Ip6::Udp::SocketHandle *>(aSocket));
+}
+
 otError otUdpClose(otInstance *aInstance, otUdpSocket *aSocket)
 {
     Instance &instance = *static_cast<Instance *>(aInstance);

src/core/net/dhcp6_server.cpp

@@ -133,8 +133,13 @@ Error Server::UpdateService(void)
 
 void Server::Start(void)
 {
+    VerifyOrExit(!mSocket.IsOpen());
+
     IgnoreError(mSocket.Open(&Server::HandleUdpReceive, this));
     IgnoreError(mSocket.Bind(kDhcpServerPort));
+
+exit:
+    return;
 }
 
 void Server::Stop(void)

src/core/net/udp6.cpp

@@ -87,6 +87,11 @@ Error Udp::Socket::Open(otUdpReceive aHandler, void *aContext)
     return Get<Udp>().Open(*this, aHandler, aContext);
 }
 
+bool Udp::Socket::IsOpen(void) const
+{
+    return Get<Udp>().IsOpen(*this);
+}
+
 Error Udp::Socket::Bind(const SockAddr &aSockAddr, otNetifIdentifier aNetifIdentifier)
 {
     return Get<Udp>().Bind(*this, aSockAddr, aNetifIdentifier);
@@ -186,6 +191,8 @@ Error Udp::Open(SocketHandle &aSocket, otUdpReceive aHandler, void *aContext)
 {
     Error error = kErrorNone;
 
+    OT_ASSERT(!IsOpen(aSocket));
+
     aSocket.GetSockName().Clear();
     aSocket.GetPeerName().Clear();
     aSocket.mHandler = aHandler;
@@ -308,6 +315,8 @@ Error Udp::Close(SocketHandle &aSocket)
 {
     Error error = kErrorNone;
 
+    VerifyOrExit(IsOpen(aSocket));
+
 #if OPENTHREAD_CONFIG_PLATFORM_UDP_ENABLE
     error = otPlatUdpClose(&aSocket);
 #endif

src/core/net/udp6.hpp

@@ -171,6 +171,14 @@ public:
          */
         Error Open(otUdpReceive aHandler, void *aContext);
 
+        /**
+         * This method returns if the UDP socket is open.
+         *
+         * @returns If the UDP socket is open.
+         *
+         */
+        bool IsOpen(void) const;
+
         /**
          * This method binds the UDP socket.
          *
@@ -446,6 +454,16 @@ public:
      */
     Error Open(SocketHandle &aSocket, otUdpReceive aHandler, void *aContext);
 
+    /**
+     * This method returns if a UDP socket is open.
+     *
+     * @param[in]  aSocket   A reference to the socket.
+     *
+     * @returns If the UDP socket is open.
+     *
+     */
+    bool IsOpen(const SocketHandle &aSocket) const { return mSockets.Contains(aSocket); }
+
     /**
      * This method binds a UDP socket.
      *