ClientSecure.available() fix for connection closed by remote socket

[JAndrassy]

for connection closed by remote socket the NetworkClientSecure.available() method:

1. logged an error.
2. returned a negative value (the error code)

The error logging is skipped for error code returned in this case. This error code is skipped in ssl_client.cpp _handle_error too.

I tested it with modified WiFiClientInsecure example

#include <NetworkClientSecure.h>
#include <WiFi.h>

const char *ssid = "your-ssid";          // your network SSID (name of wifi network)
const char *password = "your-password";  // your network password

const char *server = "arduino.tips";  // Server URL

NetworkClientSecure client;

void setup() {
  Serial.begin(115200);
  delay(500);

  Serial.print("Attempting to connect to SSID: ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(1000);
  }
  Serial.print("Connected to ");
  Serial.println(ssid);

  Serial.println("\nStarting connection to server...");
  client.setInsecure();  //skip verification
  if (!client.connect(server, 443)) {
    Serial.println("Connection failed!");
  } else {
    Serial.println("Connected to server!");
    client.println("GET /asciilogo.txt HTTP/1.1");
    client.print("Host: ");
    client.println(server);
    client.println("Connection: close");
    client.println();

    while (client.connected()) {
      String line = client.readStringUntil('\n');
      if (line == "\r") {
        Serial.println("headers received");
        break;
      }
    }
    while (client.available()) {
      char c = client.read();
      Serial.write(c);
    }
    client.stop();
  }
}

void loop() {
  delay(1);
}

without the fix it logged

[  2572][E][NetworkClientSecure.cpp:308] available(): Closing connection on failed available check
[  2587][E][NetworkClient.cpp:315] setSocketOption(): fail on 0, errno: 9, "Bad file number"
�

the setSocketOption error and the strange character were the result of read which was executed because available() didn't return a 0 but a negative value.

[github-actions]

	Messages
📖	🎉 Good Job! All checks are passing!

👋 Hello JAndrassy, we appreciate your contribution to this project!

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Generated by 🚫 dangerJS against 714e32c

[github-actions]

Test Results

 56 files   56 suites   7m 6s ⏱️
 21 tests  18 ✅ 0 💤 3 ❌
135 runs  131 ✅ 0 💤 4 ❌

For more details on these failures, see this check.

Results for commit 714e32c.

♻️ This comment has been updated with latest results.

[github-actions]

Memory usage test (comparing PR against master branch)

The table below shows the summary of memory usage change (decrease - increase) in bytes and percentage for each target.

Memory	FLASH [bytes]		FLASH [%]		RAM [bytes]		RAM [%]
Target	DEC	INC	DEC	INC	DEC	INC	DEC	INC
ESP32S3	0	0	0.00	0.00	0	0	0.00	0.00
ESP32S2	0	0	0.00	0.00	0	0	0.00	0.00
ESP32C3	0	0	0.00	0.00	0	0	0.00	0.00
ESP32C6	0	0	0.00	0.00	0	0	0.00	0.00
ESP32	0	0	0.00	0.00	0	0	0.00	0.00

Click to expand the detailed deltas report [usage change in BYTES]

Target	ESP32S3		ESP32S2		ESP32C3		ESP32C6		ESP32
Example	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM
NetworkClientSecure/examples/WiFiClientInsecure	-	-	-	-	-	-	-	-	-	-
NetworkClientSecure/examples/WiFiClientPSK	-	-	-	-	-	-	-	-	-	-
NetworkClientSecure/examples/WiFiClientSecure	-	-	-	-	-	-	-	-	-	-
NetworkClientSecure/examples/WiFiClientSecureEnterprise	-	-	-	-	-	-	-	-	-	-
NetworkClientSecure/examples/WiFiClientSecureProtocolUpgrade	-	-	-	-	-	-	-	-	-	-
NetworkClientSecure/examples/WiFiClientShowPeerCredentials	-	-	-	-	-	-	-	-	-	-
NetworkClientSecure/examples/WiFiClientTrustOnFirstUse	-	-	-	-	-	-	-	-	-	-

[me-no-dev]

NetworkClientSecure::available() returns int, so is it wrong to return negative value?

[JAndrassy]

https://www.arduino.cc/reference/en/language/functions/communication/stream/streamavailable/

Returns The number of bytes available to read.

many test it as boolean, as does the example from the NetworkClientSecure library used to test this PR

[everslick]

Will this be backported to 2.0.x also?

[me-no-dev]

we have no such plans. IDF 4.4. goes EOL next month. You are welcome to add PR and we will merge it though