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Bug #4168

RAN decode: BSSMAP: BSSMAP data truncated, discarding message

Added by fixeria 3 months ago. Updated 2 months ago.

Status:
In Progress
Priority:
Normal
Assignee:
Category:
-
Target version:
-
Start date:
08/22/2019
Due date:
% Done:

90%

Resolution:
Tags:

Description

We're running Osmocom based network at the CCCamp 2019. I noticed the following errors happening quite often (~once per second):

Thu Aug 22 15:54:52 2019 DBSSAP ERROR libmsc/ran_msg_a.c:764 msc_a(IMSI-26242340300XXXX:MSISDN-XXXX:TMSI-0xA73E055A:GERAN-A-77923:LU)[0x5563947521e0]{MSC_A_ST_AUTH_CIPH}: RAN decode: BSSMAP: BSSMAP data truncated, discarding message
Thu Aug 22 15:54:53 2019 DBSSAP ERROR libmsc/ran_msg_a.c:764 msc_a(IMSI-26242340300XXXX:MSISDN-XXXX:TMSI-0xA8EFE03F:GERAN-A-77925:LU)[0x5563947c0250]{MSC_A_ST_AUTH_CIPH}: RAN decode: BSSMAP: BSSMAP data truncated, discarding message
Thu Aug 22 15:54:53 2019 DBSSAP ERROR libmsc/ran_msg_a.c:764 msc_a(IMSI-26242340300XXXX:MSISDN-XXXX:TMSI-0x5B526072:GERAN-A-77927:LU)[0x5563946f3d70]{MSC_A_ST_AUTH_CIPH}: RAN decode: BSSMAP: BSSMAP data truncated, discarding message

History

#1 Updated by neels 3 months ago

DVLR NOTICE SUBSCR(...) gratuitous ID RESPONSE?!? (vlr.c:1182)                               
DBSSAP ERROR msc_a(...)[0x5563947ace40]{MSC_A_ST_AUTHENTICATED}: RAN decode: BSSMAP: BSSMAP data truncated, discarding message (ran_msg_a.c:764)

I've got a pcap, but would rather not publish it.
I managed to get the "gratuitous" message reproduced in a C test, but not the "data truncated" part...

Still looking.

#2 Updated by neels 3 months ago

The "gratuitous ID RESPONSE" message comes up because no vlr_subscr->lu_fsm is present.
It happens for all non-LU Layer3-Complete that do ciphering: Paging response or CM Service Request.
So the error message is completely bogus on those cases.

#3 Updated by neels 2 months ago

#4 Updated by neels 2 months ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 90

#5 Updated by neels 2 months ago

  • Assignee set to neels

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