There shouldn't be any knowledge of the upper layer in the NS layer.
The PCU / SGSN / gbproxy have to add the pointer when parsing the primitives.
Change-Id: Id7edb8feb96436ba170383fc62d43ceb16955d53
I was reading through the code and noticed many functions not
documented yet, or with incomplete documentation. Change that.
Change-Id: I85a2419604a9fd9ff3c4828a7463e222652f77bf