tree 370d0bed4efcab87e3bb7ce734c5518f297e4487
parent c4f9bf3142f54b63174f653b07103dd6ab36b1ae
author Jacob Erlbeck <jerlbeck@sysmocom.de> 1415284990 +0100
committer Holger Hans Peter Freyther <holger@moiji-mobile.com> 1415956769 +0100

sgsn: Don't assign a new P-TMSI if one is pending

Currently every time an RA Update Req or an Attach Req is processed, a
new P-TMSI is allocated. When an MS issues another of these messages
before it has completed the first procedure, old_ptmsi is replaced by
ptmsi (and thus lost) and ptmsi is replaced by the newly allocated
P-TMSI. This can confuse the gbproxy, which can loose track of the
logical link then. At least a Blackberry emits a double set of RA Upd
Req messages from time to time which may be just 20ms apart.

This patch adds a check whether mm->ptmsi or mm->old_ptmsi are set.
If both are set, the P-TMSI is not re-allocated. This is only the
case, when the Complete message has not been received yet, since that
message will reset old_ptmsi.

Sponsored-by: On-Waves ehf