.NET Binding: Setting keepAliveTimeout to TimeSpan.Max will flood connection

[sidhoda]

TimeSpan.Max is converted to milliseconds as 922337203685477, which is passed into TimeDuration ctor as a duration_t value of -580800 nanoseconds. This causes the keep alive timer to constantly fire, flooding the connection.

The following fix works, however I'm sure there's a better way.

opendnp3::TimeDuration Conversions::ConvertTimespan(System::TimeSpan ts)
{
    if (ts == System::TimeSpan::MaxValue)
        return opendnp3::TimeDuration::Max();

    return ConvertMilliseconds(ts.Ticks / System::TimeSpan::TicksPerMillisecond);
}

[sidhoda]

Just to add this is on x86 build, in case that matters.

[jadamcrain]

Is this a regression in3.0 or also an issue on 2.x?

[sidhoda]

We believe it was a regression in 3.0.
There was a previous similar bug #175 fixed in 2.x

[jadamcrain]

The underlying issue is that we switched the duration representation in 3.0 to use std::chrono::duration which overflows here only on 32-bit platforms.

We need to clamp the values to their max/min representations here.

std::chrono is kind of a dumpster fire with all the special rules and different bit widths for different templates specializations :/

https://en.cppreference.com/w/cpp/chrono/duration

[jadamcrain]

@sidhoda Can you continue your evaluation on the develop branch? I've just merged a PR to handle the overflow, but want to be sure in our environment before doing a release

[dwiley007]

@jadamcrain I've tested the change on behalf of @sidhoda and it no longer floods the connection.