ESP8266 unable to reconnect WiFi

[gskjold]

If I let my device connect to MQTT and deauth the device from my WiFi, it will not reconnect. If I run the same code, but to not connect to MQTT, WiFi reconnect works just fine. I have tried two different MQTT libraries with the same result, so I suspect it is something other than the MQTT lib itself.

Code with the problem is here:
https://github.com/gskjold/AmsToMqttBridge/tree/dev-1.6.0

Master brach is ok, see difference here:
UtilitechAS/amsreader-firmware#154

ESP WiFi debugging enabled, output from start:

SDK:2.2.2-dev(38a443e)/Core:3.0.2=30002000/lwIP:STABLE-2_1_2_RELEASE/glue:1.2-48-g7421258/BearSSL:6105635
scandone
state: 0 -> 2 (b0)
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0
aid 2
cnt

connected with no23-han, channel 1
dhcp client start...
wifi evt: 0
ip:192.168.233.207,mask:255.255.255.0,gw:192.168.233.1
wifi evt: 3
[hostByName] Host: 192.168.233.71 is a IP!
pm open,type:" 0
state: � -> " (!R8)
rm 0
pm close ?
wifi evt: 1
STA disconnect: 6
reconnect
state: " -> 0 (0)
scandone
state: 0 -> " (?8)
state: " -> @ (0)
state: @ -> � (i8)
add 0
aid "
cnt
state: � -> " (�R8)
rm 0
wifi evt: 1
STA disconnect: 2
reconnect
state: " -> 0 (0)
scandone
state: 0 -> " (?8)
state: " -> @ (0)
state: @ -> � (i8)
add 0
aid "
cnt
state: � -> " (�R8)
rm 0
wifi evt: 1
STA disconnect: 2
reconnect
state: " -> 0 (0)
scandone
state: 0 -> " (?8)
state: " -> @ (0)
state: @ -> � (i8)
add 0
aid "
cnt
state: � -> " (�R8)
rm 0
wifi evt: 1
STA disconnect: 2

Endless repeat of reconnect with disconnect: 2 (REASON_AUTH_EXPIRE)

[mcspr]

I think you forgot to mention the duplicate at 256dpi/arduino-mqtt repo
256dpi/arduino-mqtt#274 (comment)
UtilitechAS/amsreader-firmware@bc6d45e

Specific to the esp8266 code

• in the current version, stack inside of loop() and setup() is limited to 4096 bytes. declaring char buf[MAX_PEM_SIZE] twice will certainly write outside of it's bounds
  (...although, there is -fstack-protector, but I wonder if it would trigger under these conditions b/c we don't specifically overwrite the guards, but somewhere else outside of them)
• no need for any temporaries when reading certs, x509list constructor can accept File as argument (b/c it implements Stream)

@@ -960,9 +971,7 @@ void MQTT_connect() {
                                debugI("Found MQTT CA file");
                                file = LittleFS.open(FILE_MQTT_CA, "r");
                                #if defined(ESP8266)
-                                       char caStr[MAX_PEM_SIZE];
-                                       file.readBytes(caStr, file.size());
-                                       BearSSL::X509List *serverTrustedCA = new BearSSL::X509List(caStr);
+                                       BearSSL::X509List *serverTrustedCA = new BearSSL::X509List(file);
                                        mqttSecureClient->setTrustAnchors(serverTrustedCA);
                                #elif defined(ESP32)
                                        mqttSecureClient->loadCACert(file, file.size());

---

btw Espsoftwareserial is already included in the esp8266 Core distribution https://github.com/esp8266/Arduino/tree/master/libraries/
no need to explicitly pin it (unless you really want that specific version)

[gskjold]

Yes, sorry, forgot to update this post. Thank you for clearing up what was going on here, I suspected it was something like this when I realized what change caused the problem. Days have been wasted... Thank you for providing a better solution.

I did not know about SoftwareSerial being included, I will change my settings accordingly :)