WiFiClientSecure returns 0 for remoteIP(), remotePort(), localIP(), localPort() calls

[JiriBilek]

Basic Infos

• This issue complies with the issue POLICY doc.
• I have read the documentation at readthedocs and the issue is not addressed there.
• I have tested that the issue is present in current master branch (aka latest git).
• I have searched the issue tracker for a similar issue.
• [n/a ] If there is a stack dump, I have decoded it.
• I have filled out all fields below.

Platform

• Hardware: ESP-01 (but doesn't matter)
• Core Version: latest git (d3eddeb)
• Development Env: Arduino IDE
• Operating System: Windows

Settings in IDE

• Module: Generic ESP8266 Module
• Flash Mode: DOUT
• Flash Size: 1MB
• lwip Variant: v2.1 Lower Memory
• Reset Method: dtr
• Flash Frequency: 40Mhz
• CPU Frequency: 80Mhz
• Upload Using: SERIAL
• Upload Speed: 115200

Problem Description

The functions WiFiClientSecure.remoteIP(), remotePort(), localIP(), localPort() return 0. This is caused by the fact, that WiFiClientSecure is derived from WiFiClient but doesn't use its ClientContext* _client variable. It uses WiFiClient class that is the base of WiFiClientSecureCtx* _ctx instead, as is written in the documentation of the WiFiClientSecure class.

The problem is, that WiFiClientSecure.remoteIP() calls WiFiClient.remoteIP() with _client=nullptr instead of calling something like WiFiClientSecure._ctx->remoteIP(). The same holds with the other 3 function mentioned in the title.

The solution is to make these functions virtual and override them in WiFiClientSecure class.
I am creating a PR in no time.

MCVE Sketch

The sketch is a modified WiFiClient example

/*
    This sketch establishes a TCP connection to a "quote of the day" service.
    It sends a "hello" message, and then prints received data.
*/

#include <ESP8266WiFi.h>

#ifndef STASSID
#define STASSID "xxx"
#define STAPSK  "xxx"
#endif

const char* ssid     = STASSID;
const char* password = STAPSK;

const char* host = "github.com";
const uint16_t port = 443;

void setup() {
  Serial.begin(115200);

  // We start by connecting to a WiFi network

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  /* Explicitly set the ESP8266 to be a WiFi-client, otherwise, it by default,
     would try to act as both a client and an access-point and could cause
     network-issues with your other WiFi-devices on your WiFi-network. */
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  static bool wait = false;

  Serial.print("connecting to ");
  Serial.print(host);
  Serial.print(':');
  Serial.println(port);

  // Use WiFiClient class to create TCP connections
  WiFiClientSecure client;
  client.setInsecure();
  if (!client.connect(host, port)) {
    Serial.println("connection failed");
    delay(5000);
    return;
  }

  Serial.print(client.remoteIP().toString().c_str());
  Serial.print(':');
  Serial.println(client.remotePort());

  // Close the connection
  Serial.println();
  Serial.println("closing connection");
  client.stop();

  if (wait) {
    delay(300000); // execute once every 5 minutes, don't flood remote service
  }
  wait = true;
}

Debug Messages

expected:

WiFi connected
IP address:
192.168.1.137
connecting to github.com:443
140.82.121.4:443

got:

WiFi connected
IP address:
192.168.1.137
connecting to github.com:443
(IP unset):0

[regdomain]

Thanks for your fix, you're great, man! I've dug through the whole Internet trying to figure out why server.client().remoteIP().toString() returns "(IP unset)"!

[JiriBilek]

Fixed with #8693