Fix W5100S socket exhaustion blocking MQTT and additional TCP clients

src/DebugConfiguration.cpp

@@ -98,7 +98,6 @@ Syslog &Syslog::logMask(uint8_t priMask)
 
 void Syslog::enable()
 {
-    this->_client->begin(this->_port);
     this->_enabled = true;
 }
 
@@ -166,14 +165,21 @@ inline bool Syslog::_sendLog(uint16_t pri, const char *appName, const char *mess
     if ((pri & LOG_FACMASK) == 0)
         pri = LOG_MAKEPRI(LOG_FAC(this->_priDefault), pri);
 
+    // W5100S: acquire UDP socket on-demand to avoid permanent socket consumption
+    if (!this->_client->begin(this->_port)) {
+        return false;
+    }
+
     if (this->_server != NULL) {
         result = this->_client->beginPacket(this->_server, this->_port);
     } else {
         result = this->_client->beginPacket(this->_ip, this->_port);
     }
 
-    if (result != 1)
+    if (result != 1) {
+        this->_client->stop();
         return false;
+    }
 
     this->_client->print('<');
     this->_client->print(pri);
@@ -193,6 +199,8 @@ inline bool Syslog::_sendLog(uint16_t pri, const char *appName, const char *mess
     this->_client->print(message);
     this->_client->endPacket();
 
+    this->_client->stop(); // W5100S: release UDP socket for other services
+
     return true;
 }
 

src/mesh/eth/ethClient.cpp

@@ -39,7 +39,6 @@ static int32_t reconnectETH()
 
 #ifndef DISABLE_NTP
             LOG_INFO("Start NTP time client");
-            timeClient.begin();
             timeClient.setUpdateInterval(60 * 60); // Update once an hour
 #endif
 
@@ -96,6 +95,7 @@ static int32_t reconnectETH()
             LOG_ERROR("NTP Update failed");
             ntp_renew = millis() + 300 * 1000; // failure, retry every 5 minutes
         }
+        timeClient.end(); // W5100S: release UDP socket for other services
     }
 #endif
 

src/mqtt/MQTT.cpp

@@ -663,7 +663,11 @@ bool MQTT::isValidConfig(const meshtastic_ModuleConfig_MQTTConfig &config, MQTTC
         }
         std::unique_ptr<PubSubClient> pubSub(new PubSubClient);
         if (isConnectedToNetwork()) {
-            return connectPubSub(parsed, *pubSub, (client != nullptr) ? *client : *clientConnection);
+            bool result = connectPubSub(parsed, *pubSub, (client != nullptr) ? *client : *clientConnection);
+            if (client == nullptr) {
+                pubSub->disconnect();
+            }
+            return result;
         }
 #else
         const char *warning = "Invalid MQTT config: proxy_to_client_enabled must be enabled on nodes that do not have a network";