Close hangs app when WithNoConnClose

[adsko]

When stun connection is created from existing connection, and WithNoConnClose is provided, Close hangs app.

[hashok]

I have the same issue. Debugging showed that Close waits for readUntilClosed go-routing to exit, but that go-routine is blocked on ReadFrom call here

stun/client.go

Line 327 in 0f7f72b

_, err := m.ReadFrom(c.c)

Workaround is to call SetReadDeadline(time.Now()) before calling Close for the stun.Client. It causes ReadFrom to immediately exit.

[adsko]

@hashok Calling SetReadDeadline(time.Now()) closes the connection.

[hashok]

@adsko It shouldn't do that. Make sure you call SetReadDeadline(time.Time{}) on the underlying connection after stun connection is closed to restore the original behavior of the underlying connection.

[stv0g]

How do we fix this issue?

Setting the read deadline in Close() is not feasible since the connection only implements the following interface:

// Connection wraps Reader, Writer and Closer interfaces.
type Connection interface {
	io.Reader
	io.Writer
	io.Closer
}

We could call c.wg.Done() manually to unblock the c.wg.Wait() in Close().
However, that would leave us with a leaked Goroutine and might cause some panic if the connection still ends up receiving data while the client has been closed?