v2c: connexion TCP persistante — fin des rafales SYN

Diagnostic tcpdump : le plugin ouvrait/fermait la socket Modbus TCP à
chaque cycle de poll, générant 6-7 paquets SYN consécutifs qui saturaient
l'ESP32 WiFi de la borne (timeouts en boucle). mbpoll avec une connexion
persistante = 0 % d'échec.

Corrections :
- connectDevice() : guard "si déjà connecté → no-op" (élimine le warning
  "already in ConnectedState" et les FIN/RESET parasites).
- onConnectionStateChanged(true) : appelle initialize() directement au lieu
  de setReachable(true) — évite la ré-entrée initialize() via reachableChanged.
- initialize() : setReachable(true) uniquement au succès, après lecture
  MinIntensity/MaxIntensity ; guard || m_updating ajouté.
- update() : guard || m_initializing ajouté (pas de poll concurrent avec init).
- Timer : if (!master->update()) master->connectDevice() — le socket reste
  ouvert tant que la connexion TCP est active ; connectDevice() n'est appelé
  que quand le TCP est réellement coupé.
- initializationFinished(thing) : master->update() immédiat après reconnect.
- reachableChanged handler : suppression de l'appel à initialize() (déplacé).

Résultat attendu tcpdump : 1 seul SYN à l'établissement, puis uniquement
des échanges Modbus (P. length 12/13) toutes les 30 s, aucun FIN/RESET.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

v2c/integrationpluginv2c.cpp

@@ -67,18 +67,19 @@ void IntegrationPluginV2c::setupThing(ThingSetupInfo *info)
 
     connect(info, &ThingSetupInfo::aborted, master, &TrydanModbusTcpMaster::deleteLater);
 
-    // Reachable → initialize (reads MinIntensity, MaxIntensity).
-    // Lost → set disconnected state with timestamp for SAV visibility.
+    // Reachability is driven by Modbus poll results (not TCP state directly).
+    // initialize() is now called from TrydanModbusTcpMaster::onConnectionStateChanged(true)
+    // so we no longer need to call it here — this handler only updates the UI.
     connect(master, &TrydanModbusMaster::reachableChanged, thing,
-            [this, thing, master](bool reachable) {
-        if (reachable) {
-            master->initialize();
-        } else {
+            [this, thing](bool reachable) {
+        if (!reachable) {
             setDisconnectedState(thing, QStringLiteral("timeout Modbus — vérifier signal WiFi de la borne"));
         }
+        // reachable=true: UI cleared by next successful poll (updateThingStates).
     });
 
-    // After init, expose the configured current range and finish setup.
+    // After init (first time or reconnect): expose current range and kick an immediate poll
+    // so states are refreshed without waiting up to 30 s for the next timer tick.
     connect(master, &TrydanModbusMaster::initializationFinished, thing,
             [this, thing, master](bool success) {
         if (!success) {
@@ -89,6 +90,9 @@ void IntegrationPluginV2c::setupThing(ThingSetupInfo *info)
         thing->setStateMinMaxValues(trydanMaxChargingCurrentStateTypeId,
                                     master->minIntensity(),
                                     master->maxIntensity());
+        // Immediate first poll.  For setup the info handler below also calls update();
+        // the m_updating guard makes the second call a no-op.
+        master->update();
     });
 
     connect(master, &TrydanModbusMaster::initializationFinished, info,
@@ -124,12 +128,12 @@ void IntegrationPluginV2c::postSetupThing(Thing *thing)
     m_pluginTimer = hardwareManager()->pluginTimerManager()->registerTimer(30);
     connect(m_pluginTimer, &PluginTimer::timeout, this, [this]() {
         for (TrydanModbusTcpMaster *master : m_tcpMasters) {
-            if (master->reachable()) {
-                master->update();
-            } else {
-                // TCP connection may have dropped (charger WiFi glitch).
-                // connectDevice() is idempotent on an already-connecting socket;
-                // the 30s timer provides the reconnect backoff — no busy-loop.
+            // update() returns false only when the TCP socket is not connected
+            // (or a poll/init is already running).  connectDevice() is a no-op
+            // if the socket is already connected — it will NOT close and reopen
+            // the connection, avoiding the SYN bursts that saturate the ESP32 WiFi.
+            // Normal path: TCP stays open, only Modbus frames exchanged every 30 s.
+            if (!master->update()) {
                 master->connectDevice();
             }
         }

v2c/trydanmodbustcpmaster.cpp

@@ -44,6 +44,11 @@ void TrydanModbusTcpMaster::setHostAddress(const QHostAddress &address)
 
 void TrydanModbusTcpMaster::connectDevice()
 {
+    // Guard: calling connectDevice() on an already-connected QModbusTcpClient
+    // logs a warning AND closes+reopens the TCP socket, generating a SYN burst
+    // that saturates the Trydan ESP32 WiFi stack.  Skip if already connected.
+    if (m_modbusTcpMaster->connected())
+        return;
     m_modbusTcpMaster->connectDevice();
 }
 
@@ -55,7 +60,10 @@ void TrydanModbusTcpMaster::disconnectDevice()
 
 bool TrydanModbusTcpMaster::initialize()
 {
-    if (!m_modbusTcpMaster->connected() || m_initializing)
+    // Also guard against an ongoing poll: init and update share the same sequential
+    // read pipeline; running both concurrently would interleave FC3 transactions
+    // and corrupt both sequences.
+    if (!m_modbusTcpMaster->connected() || m_initializing || m_updating)
         return false;
 
     m_initializing = true;
@@ -70,6 +78,12 @@ bool TrydanModbusTcpMaster::initialize()
             // on a spurious 0 and caps to 32 on a spurious 65535.
             m_minIntensity = qBound(6, m_minIntensity, 32);
             m_maxIntensity = qBound(6, m_maxIntensity, 32);
+            // TCP is live and init succeeded — mark reachable so the plugin can
+            // update states.  This is the ONLY place setReachable(true) is called
+            // from the connection path; onConnectionStateChanged(true) no longer
+            // does it directly, avoiding a re-entrant initialize() call via the
+            // reachableChanged signal.
+            setReachable(true);
         }
         emit initializationFinished(ok);
     });
@@ -78,7 +92,8 @@ bool TrydanModbusTcpMaster::initialize()
 
 bool TrydanModbusTcpMaster::update()
 {
-    if (!m_modbusTcpMaster->connected() || m_updating)
+    // Guard against concurrent init: both use the same sequential FC3 pipeline.
+    if (!m_modbusTcpMaster->connected() || m_updating || m_initializing)
         return false;
 
     m_updating = true;
@@ -261,9 +276,15 @@ void TrydanModbusTcpMaster::onConnectionStateChanged(bool connected)
 {
     if (connected) {
         m_errorCount = 0;
-        // Signal reachability so the plugin calls initialize().
-        setReachable(true);
+        // Start init directly — do NOT call setReachable(true) here.
+        // setReachable(true) is deferred to initialize()'s success callback so the
+        // plugin's reachableChanged handler can no longer trigger a second initialize()
+        // call via signal re-entry.  The connection sequence is:
+        //   TCP up → initialize() → setReachable(true) → reachableChanged(true) → UI update
+        initialize();
     } else {
+        // TCP actually dropped: abort any in-flight sequence and go offline.
+        // The 30s poll timer will call connectDevice() → new TCP handshake.
         m_updating     = false;
         m_initializing = false;
         setReachable(false);