support_wifi.ino: Check if WiFi is connected before getting localIP

[Otamay]

Description:

I'm using a ZB-GW03-V1.2 device (https://templates.blakadder.com/ewelink_ZB-GW03). With the following scenario:

• Device connected via Ethernet (unsure yet if happens without Ethernet connected)
• At least one SSID configured, SSIDs configured must not be able to be connected to

Results in a panic after failing to connect to the WiFi for 1-2 minute aprox. The device then reboots.

This is the error shown via Serial:

[15:08:45]00:02:20.938 WIF: Connect failed as AP cannot be reached [15:08:45]Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled. [15:08:45]
[15:08:45]Core  1 register dump:
[15:08:45]PC      : 0x4016dc6a  PS      : 0x00060c30  A0      : 0x80142249  A1      : 0x3ffbc220  
[15:08:45]A2      : 0x3ffd73f0  A3      : 0x3ffbc240  A4      : 0x80090b1a  A5      : 0x3ffb1a30  
[15:08:45]A6      : 0x00000003  A7      : 0x00060023  A8      : 0x801c9456  A9      : 0x00000000  
[15:08:45]A10     : 0x3ffbc240  A11     : 0x00000000  A12     : 0x80000020  A13     : 0x80000000  
[15:08:45]A14     : 0x00000005  A15     : 0x00000001  SAR     : 0x00000015  EXCCAUSE: 0x0000001c  
[15:08:45]EXCVADDR: 0x801c9539  LBEG    : 0x4008b4e8  LEND    : 0x4008b4fe  LCOUNT  : 0xffffffff  
[15:08:45]
[15:08:45]
[15:08:45]Backtrace: 0x4016dc67:0x3ffbc220 0x40142246:0x3ffbc240 0x4013c189:0x3ffbc270 0x40119906:0x3ffbc2b0 0x400e2ee8:0x3ffbc2f0 0x401109cb:0x3ffbc340

Checking it with xtensa-esp32-elf-addr2line:

_ZNK16NetworkInterface7localIPEv$isra$0
/home/gitpod/.platformio/packages/framework-arduinoespressif32/libraries/Network/src/NetworkInterface.cpp:660 _ZN12WiFiSTAClass7localIPEv
/home/gitpod/.platformio/packages/framework-arduinoespressif32/libraries/WiFi/src/WiFiSTA.cpp:282 _Z11WifiHasIPv4v
/workspace/Tasmota-build/tasmota/tasmota_support/support_wifi.ino:517 _Z10WifiEventsP15arduino_event_t
/workspace/Tasmota-build/tasmota/tasmota_support/support_wifi.ino:1492 _ZN13NetworkEvents14_checkForEventEv
/home/gitpod/.platformio/packages/framework-arduinoespressif32/libraries/Network/src/NetworkEvents.cpp:137

Points to support_wifi.ino having a problem handling the ip pointer when the WiFi is not connected. The proposed patch checks if the WiFi is connected prior to getting the IP.

I don't know if this is a bug from Tasmota or in the ESP32 libraries themselves, but with this change the panic is gone.

Related issue (if applicable): No related issue

Checklist:

• [ x] The pull request is done against the latest development branch
• [ x] Only relevant files were touched
• [ x] Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.8
• [ x] The code change is tested and works with Tasmota core ESP32 V.3.1.3.250302
• [ x] I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass

[s-hadinger]

Thanks. This sound's reasonable. I'm surprised I never saw this problem although thorough testing when I added this code. Maybe this was triggered by more recent library.

[arendst]

Verified to happen randomly within 1 to 7 minutes (On an olimex PoE and disabled wifi on MiktoTik AP). Researching....

[arendst]

The exception

00:02:50.949 WIF: Connect failed as AP cannot be reached
Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled.

Core  1 register dump:
PC      : 0x401813ba  PS      : 0x00060830  A0      : 0x80155589  A1      : 0x3ffaf790  
A2      : 0x3ffd6dd8  A3      : 0x3ffaf7b0  A4      : 0x80090ce6  A5      : 0x3ffb1a30  
A6      : 0x00000003  A7      : 0x00060023  A8      : 0x801d872a  A9      : 0x00000000  
A10     : 0x3ffaf7b0  A11     : 0x00000000  A12     : 0x80000020  A13     : 0x80000000  
A14     : 0x00000005  A15     : 0x00000001  SAR     : 0x0000001e  EXCCAUSE: 0x0000001c  
EXCVADDR: 0x801d880d  LBEG    : 0x4008b68c  LEND    : 0x4008b6a2  LCOUNT  : 0xffffffff  

Backtrace: 0x401813b7:0x3ffaf790 0x40155586:0x3ffaf7b0 0x401555a6:0x3ffaf7e0 0x4012ae3a:0x3ffaf820 0x400e4328:0x3ffaf860 0x401202a7:0x3ffaf8b0

occurs in IPAddress NetworkInterface::localIP() calling idf esp_netif_get_ip_info(_esp_netif, &ip):

IPAddress NetworkInterface::localIP() const {
  if (_esp_netif == NULL) {
    return IPAddress();
  }
  esp_netif_ip_info_t ip;
  if (esp_netif_get_ip_info(_esp_netif, &ip)) {
    return IPAddress();
  }
  return IPAddress(ip.ip.addr);
}

As a workaround this change, based on your PR, is made in our functon WifiGetIPv4(IPAddress *ip):

bool WifiGetIPv4(IPAddress *ip)
{
  uint32_t wifi_uint = (WL_CONNECTED == WiFi.status()) ? (uint32_t)WiFi.localIP() : 0;  // See issue #23115
  if (ip != nullptr) { *ip = wifi_uint; }
  return wifi_uint != 0;
}

Testing for a valid WiFi connection before calling WiFi.localIP().

As we use WiFi.localIP() a lot there might be other situations where the exception could occur.