SSLClient terminating when flushing buffer #30
Description
I am trying to connect my ESP32 to my MQTT Broker (mosquitto on RaspberryPi) via WiFi.
My code is based on the EthernetMQTT example, but i exchanged the ethernet client for WiFi.
The esp32 succesfully connects to the Broker and publishes a first message, but afte that I get the errormessage:
(SSLClient)(SSL_WARN)(m_run_until): Terminating because the ssl engine closed
(SSLClient)(SSL_ERROR)(flush): Could not flush write buffer!
It seems that using the flush() function is crashing the sslClient, wich is unfortunate, because as described in #9, not using the flush() function after every write to the network results in an a stack overflow.
How do I go about this error? Is it possible to get a kind of stable connection?
My full code:
/**
A BLE client example that is rich in capabilities.
There is a lot new capabilities implemented.
author unknown
updated by chegewara
*/
#include <WiFi.h>
#include <PubSubClient.h>
//SSL
#include <SSLClient.h>
#include "certificates.h" // This file must be regenerated
const char my_cert[] = "FIXME";
const char my_key[] = "FIXME";
SSLClientParameters mTLS = SSLClientParameters::fromPEM(my_cert, sizeof my_cert, my_key, sizeof my_key);
// Setup Wifi
const char* ssid = "...";
const char* password = "...";
const char* mqtt_server = "192.168.2.105";
WiFiClient espClient;
SSLClient espClientSSL(espClient, TAs, (size_t)TAs_NUM, A5);
PubSubClient client(espClientSSL);
void setup_wifi() {
delay(10);
// We start by connecting to a WiFi network
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
}
void reconnect() {
// Loop until we're reconnected
while (!client.connected()) {
Serial.print("Attempting MQTT connection...");
// Attempt to connect
if (client.connect("ESP32Client")) {
Serial.println("connected");
// Once connected, publish an announcement...
client.publish("outTopic", "hello world");
// This is a workaround to address https://github.com/OPEnSLab-OSU/SSLClient/issues
Serial.print("calling flush() \n");
espClientSSL.flush();
Serial.print("flush() finished \n");
// Subscribe
//client.subscribe("testtopic/Win");
// This is a workaround to address https://github.com/OPEnSLab-OSU/SSLClient/issues
//espClientSSL.flush();
} else {
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
void callback(char* topic, byte* payload, unsigned int length) {
Serial.print("Message arrived [");
Serial.print(topic);
Serial.print("] ");
for (int i = 0; i < length; i++) {
Serial.print((char)payload[i]);
}
Serial.println();
}
void setup() {
Serial.begin(115200);
while (!Serial);
// Enable mutual TLS with SSLClient
espClientSSL.setMutualAuthParams(mTLS);
//Connecting to Wifi and MQTT Broker
setup_wifi();
client.setServer(mqtt_server, 8883);
client.setCallback(callback);
}
void loop() {
//MQTT
if (!client.connected()) {
reconnect();
}
client.loop();
//Serial.print("Attempting MQTT hello there!");
client.publish("testtopic/ESP", "hello there!");
// This is a workaround to address https://github.com/OPEnSLab-OSU/SSLClient/issues
espClientSSL.flush();
delay(3000); // Delay a second between loops.
} // End of loop
longer serial output:
...
WiFi connected
Attempting MQTT connection...connected
calling flush()
(SSLClient)(SSL_WARN)(m_run_until): Terminating because the ssl engine closed
(SSLClient)(SSL_ERROR)(flush): Could not flush write buffer!
flush() finished
Attempting MQTT connection...connected
calling flush()
Serverside log:
1609262639: New connection from 192.168.2.73 on port 8883.
1609262639: New client connected from 192.168.2.73 as ESP32Client (p2, c1, k15).
1609262661: Client ESP32Client has exceeded timeout, disconnecting.
1609262662: New connection from 192.168.2.73 on port 8883.
1609262662: New client connected from 192.168.2.73 as ESP32Client (p2, c1, k15).