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.

[sfromis]

Unfortunate side effect of this is that DNS server IP addresses become zeroed next boot.

[s-hadinger]

I'm not sure to understand the direct link, but maybe it creates a problem in WiFiHelper::scrubDNS(void)

[github-actions[bot]]

This PR has been automatically marked as stale because it hasn't any activity in last few weeks. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This PR was automatically closed because of being stale.