Pushed by truck. Correct behavior?

The last thing I went to Freiburg for a customer appointment. As is well known there are very long construction sites with 80kmh limit. So I drive in the construction site area on the right lane, cruise set at 84kmh (GPS 80kmh). I am not in a hurry, lying well in time. Suddenly a truck drives up on me, horns already from a distance and gives light hoop. I let myself be confused by nothing and continue driving like this. That certainly went 4-5km, with walk-up and light hoop. I didn’t care, was limited to 80kmh and did not try to let me get out of the way. After that, however, the behavior was already creeping me up and I would have liked to display it. However, I don’t know how I should have done it on the highway. What is the correct behavior in such situations?