class Net::SSH::Connection::Keepalive

def enabled?
  options[:keepalive]
end

def initialize(session)
  @last_keepalive_sent_at = nil
  @unresponded_keepalive_count = 0
  @session = session
  self.logger = session.logger
end

def interval
  options[:keepalive_interval] || Session::DEFAULT_IO_SELECT_TIMEOUT
end

def keepalive_maxcount
  (options[:keepalive_maxcount] || 3).to_i
end

def options
  @session.options
end

def send_as_needed(was_events)
  return if was_events
  return unless should_send?
  info { "sending keepalive #{@unresponded_keepalive_count}" }
  @unresponded_keepalive_count += 1
  @session.send_global_request("keepalive@openssh.com") { |success, response|
    debug { "keepalive response successful. Missed #{@unresponded_keepalive_count - 1} keepalives" }
    @unresponded_keepalive_count = 0
  }
  @last_keepalive_sent_at = Time.now
  if keepalive_maxcount > 0 && @unresponded_keepalive_count > keepalive_maxcount
    error { "Timeout, server #{@session.host} not responding. Missed #{@unresponded_keepalive_count - 1} timeouts." }
    @unresponded_keepalive_count = 0
    raise Net::SSH::Timeout, "Timeout, server #{@session.host} not responding."
  end
end

def should_send?
  return false unless enabled?
  return true unless @last_keepalive_sent_at
  Time.now - @last_keepalive_sent_at >= interval
end