Connection timeout when system time is set to a time in the past

[andreasgrosche]

Describe the bug

A connection timeout occurs when the system time is set to a time in the past.

Which component is your bug related to?

• Client

To Reproduce

Steps to reproduce the behavior:

1. Using this version of MQTTnet '5.0.0.1214-RC'.
2. Run the following code on Ubuntu 22.04.5 LTS.
   Adjust the host and credentials to match your MQTT broker (I only tested with a mosquitto MQTT broker running on another machine).

using MQTTnet;

var factory = new MqttClientFactory();

using var client = factory.CreateMqttClient();

var options = new MqttClientOptionsBuilder()
    .WithTcpServer("192.168.0.10")
    .WithCredentials("mosquitto", "mosquitto")
    .Build();

client.ConnectingAsync += _ =>
{
    Console.WriteLine("Connecting");
    return Task.CompletedTask;
};
client.ConnectedAsync += _ =>
{
    Console.WriteLine("Connected");
    return Task.CompletedTask;
};

client.DisconnectedAsync += _ =>
{
    Console.WriteLine("Disconnected");
    return Task.CompletedTask;
};

await client.ConnectAsync(options);

while (true)
{
}

6. The application prints Connecting and Connected as expected.
7. Change the system time to a time in the past, e.g., calling sudo timedatectl set-time '2024-12-12 04:00:00'
8. Wait for 30 s
9. The program prints Disconnected
10. The mosquitto MQTT broker prints Client ... has exceeded timeout, disconnecting

Additional context / logging

Setting the system time to a time in the future seems to be no problem.

This issue does not occur with mosquitto_sub. Tested with

mosquitto_sub -h 192.168.0.10 -t \# -u mosquitto -P mosquitto

When the MQTTnet client disconnects, the mosquitto_sub application remains running and outputs received messages and the MQTT broker prints only the timeout information for the MQTTnet client and not for the mosquitto_sub.