Implemented hearthbit client side + tests

Source/Components/Interfaces/UDPStream/UDPSClient.cpp

@@ -24,6 +24,7 @@ UDPSClient::UDPSClient()
       useMulticast(false),
       silenceTimeoutTicks(0u),
       reconnectDelayTicks(0u),
+      keepAliveIntervalTicks(0u),
       maxPayloadSize(UDPS_CLIENT_DEFAULT_MAX_PAYLOAD),
       cpuMask(0xFFFFFFFFu),
       stackSize(65536u),
@@ -33,6 +34,7 @@ UDPSClient::UDPSClient()
       connected(false),
       lastDataTicks(0u),
       disconnectTick(0u),
+      lastKeepAliveTicks(0u),
       localPort(0u),
       lastGcTicks(0u) {
 
@@ -93,6 +95,10 @@ bool UDPSClient::Initialise(StructuredDataI &data) {
     (void) data.Read("ReconnectDelay", reconnectS);
     reconnectDelayTicks = static_cast<uint64>(reconnectS) * HighResolutionTimer::Frequency();
 
+    uint32 keepAliveS = UDPS_CLIENT_DEFAULT_KEEPALIVE_INTERVAL_S;
+    (void) data.Read("KeepAliveInterval", keepAliveS);
+    keepAliveIntervalTicks = static_cast<uint64>(keepAliveS) * HighResolutionTimer::Frequency();
+
     uint32 mps = UDPS_CLIENT_DEFAULT_MAX_PAYLOAD;
     (void) data.Read("MaxPayloadSize", mps);
     maxPayloadSize = mps;
@@ -185,6 +191,18 @@ ErrorManagement::ErrorType UDPSClient::Execute(ExecutionInfo &info) {
         }
     }
 
+    // Unicast keepalive: UDPSServer evicts silent unicast clients after its
+    // ClientTimeout (default 30 s). Re-sending CONNECT would also re-trigger
+    // a CONFIG resend; an ACK refreshes the server's last-seen with no side
+    // effects, so it is the keepalive packet of choice. Multicast clients
+    // hold a persistent TCP control connection and need no keepalive.
+    if (!useMulticast && (keepAliveIntervalTicks > 0u)) {
+        if ((now - lastKeepAliveTicks) >= keepAliveIntervalTicks) {
+            SendKeepAlive();
+            lastKeepAliveTicks = now;
+        }
+    }
+
     // Periodic GC of stale reassembly slots (~every 1 s)
     uint64 gcFreq = HighResolutionTimer::Frequency();
     if ((now - lastGcTicks) >= gcFreq) {
@@ -204,6 +222,7 @@ bool UDPSClient::Connect() {
     if (ok) {
         connected     = true;
         lastDataTicks = HighResolutionTimer::Counter();
+        lastKeepAliveTicks = lastDataTicks;
         if (listener != NULL_PTR(UDPSClientListener *)) {
             listener->OnUDPSConnected();
         }
@@ -378,6 +397,25 @@ void UDPSClient::Disconnect() {
     }
 }
 
+// ---------------------------------------------------------------------------
+// Private: SendKeepAlive
+// ---------------------------------------------------------------------------
+
+void UDPSClient::SendKeepAlive() {
+    if (useMulticast || !recvSocket.IsValid()) {
+        return;
+    }
+    uint8  ackPkt[UDPS_HEADER_SIZE];
+    UDPSBuildHeader(ackPkt, UDPS_TYPE_ACK, 0u, 0u, 1u, 0u);
+    InternetHost serverDest(serverPort, serverAddr.Buffer());
+    (void) recvSocket.SetDestination(serverDest);
+    uint32 sendSize = UDPS_HEADER_SIZE;
+    if (!recvSocket.Write(reinterpret_cast<const char8 *>(ackPkt), sendSize)) {
+        /* Non-fatal: if the server is truly gone, the silence timeout
+         * triggers the usual disconnect + reconnect. */
+    }
+}
+
 // ---------------------------------------------------------------------------
 // Private: ReceiveAndProcess
 // ---------------------------------------------------------------------------

Source/Components/Interfaces/UDPStream/UDPSClient.h

@@ -92,6 +92,11 @@ public:
     /** Default delay between reconnect attempts (seconds). */
     static const uint32 UDPS_CLIENT_DEFAULT_RECONNECT_DELAY_S = 2u;
 
+    /** Default unicast keepalive interval (seconds). UDPSServer evicts silent
+     *  unicast clients after its ClientTimeout (default 30 s); the client
+     *  re-sends an ACK on this interval to stay registered. 0 disables. */
+    static const uint32 UDPS_CLIENT_DEFAULT_KEEPALIVE_INTERVAL_S = 15u;
+
     /** Default maximum payload size (bytes, excluding 17-byte header). */
     static const uint32 UDPS_CLIENT_DEFAULT_MAX_PAYLOAD = 1400u;
 
@@ -115,6 +120,7 @@ public:
      *  - DataPort        (uint16) UDP multicast data port (defaults to Port+1).
      *  - SilenceTimeout  (uint32) Seconds of no data before reconnect. Default 5.
      *  - ReconnectDelay  (uint32) Seconds to wait between reconnect attempts. Default 2.
+     *  - KeepAliveInterval (uint32) Seconds between unicast keepalive ACKs. Default 15. 0 disables.
      *  - MaxPayloadSize  (uint32) Max payload bytes per datagram, excluding header. Default 1400.
      *  - CPUMask         (uint32) CPU affinity mask for the receive thread. Default 0xFFFFFFFF.
      *  - StackSize       (uint32) Stack size for the receive thread. Default 65536.
@@ -168,6 +174,8 @@ private:
     // -------------------------------------------------------------------------
     bool Connect();
     void Disconnect();
+    /** Send a keepalive ACK to the server (unicast only, same socket). */
+    void SendKeepAlive();
     bool ReceiveAndProcess();
 
     bool ConnectUnicast();
@@ -196,6 +204,7 @@ private:
     bool         useMulticast;
     uint64       silenceTimeoutTicks;
     uint64       reconnectDelayTicks;
+    uint64       keepAliveIntervalTicks; ///< 0 = keepalive disabled
     uint32       maxPayloadSize;
     uint32       cpuMask;
     uint32       stackSize;
@@ -209,6 +218,7 @@ private:
     bool                connected;
     uint64              lastDataTicks;  ///< Ticks at last received DATA/CONFIG
     uint64              disconnectTick; ///< Ticks when we disconnected (for delay)
+    uint64              lastKeepAliveTicks; ///< Ticks at last keepalive ACK sent
 
     // Unicast
     BasicUDPSocket recvSocket;  ///< Bound to ephemeral port; receives DATA