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Bug #4052

Test uncompressed bitmaps without length

Added by lynxis about 2 months ago. Updated 5 days ago.

Status:
Closed
Priority:
Urgent
Assignee:
Target version:
-
Start date:
06/07/2019
Due date:
% Done:

100%

Spec Reference:
44.060

Description

Check and test uncompressed bitmaps without length.


Related issues

Related to OsmoPCU - Bug #3728: Problem using compressed ACK/NACK bitmaps or uncompressed bitmaps without lengthClosed12/13/2018

History

#1 Updated by lynxis about 2 months ago

  • Related to Bug #3728: Problem using compressed ACK/NACK bitmaps or uncompressed bitmaps without length added

#2 Updated by lynxis about 2 months ago

  • Assignee set to lynxis

#3 Updated by lynxis about 1 month ago

  • Priority changed from Normal to Urgent

#4 Updated by lynxis about 1 month ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 20

There is at least one corner cases, which I'ven't found in the 44.060: What happens when an EGPRS ACK/NACK does not have a Length field, but the uncompressed RBB is less the remaining rest_bits? This was possible, when less than 8 bits were remaining, so only happens when having huge packet loss.

... This is defined as spec compliant. Out of window bits should be ignored.

I've implemented a fix for this in my branch lynxis/gprs-ack-nack https://gerrit.osmocom.org/plugins/gitiles/osmo-pcu/+/lynxis/gprs-ack-nack
I will push this patch to gerrit and write test cases for the encoding.

However I want also validate the encoding of the URBB is correct at all.

#5 Updated by lynxis about 1 month ago

  • Spec Reference set to 44.060

#6 Updated by lynxis about 1 month ago

lynxis wrote:

There is at least one corner cases, which I'ven't found in the 44.060: What happens when an EGPRS ACK/NACK does not have a Length field, but the uncompressed RBB is less the remaining rest_bits? This was possible, when less than 8 bits were remaining, so only happens when having huge packet loss.

... This is defined as spec compliant. Out of window bits should be ignored.

But those bits are still within the window. They won't be ignored. And bits which represent V(R) or higher must be set to 0 (44.060 9.1.10).

#7 Updated by lynxis 12 days ago

  • Status changed from In Progress to Feedback
  • % Done changed from 20 to 90

The uncompressed bitmap will be removed.

https://gerrit.osmocom.org/c/osmo-pcu/+/14697

#8 Updated by lynxis 5 days ago

  • Status changed from Feedback to Closed
  • % Done changed from 90 to 100

The patch is now merged.

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