Attention is currently required from: pespin. Hello Jenkins Builder,

I'd like you to reexamine a change. Please visit

https://gerrit.osmocom.org/c/libosmocore/+/27224

to look at the new patch set (#2).

Change subject: gsm: [ABI BREAK] Support CellId SAI, change CellId CGI-PS id number ......................................................................

gsm: [ABI BREAK] Support CellId SAI, change CellId CGI-PS id number

Those are available in 3GPP TS 48.008 version 16.0.0 Release 16, section 3.2.2.17 Cell Identifier. It can be seen that we have a collision between the osmocom non-standard format and the SAI standard one.

This is because CGI-PS is not really a TS 48.008 Cell Identifier, but only specified in TS 48.018 and has no ID number assigned. The CGI-PS was added there because the whole osmo-bsc neighbour configuration works with CellIds to manage neighbours, so it felt natural to extend the APIs to also provide means to use CGI-PS format (TS 48.018 even refers 48.008 existance and mentions there's no explicit ID).

At the time this Cell Identifier was added, the firstly available number (11) was taken, which was of course a really bad idea since newer versions of the spec can at some point use it, which is the case if one checks for instance TS 48.008 Release 16 SAI Cell Id.

There no perfect way to fix this bad decision at the time, but the CGI-PS is only used in osmo-bsc and only for RIM related purposes, so by changing the ID of CELL_IDENT_WHOLE_GLOBAL_PS, we only break RIM under some specific CIs being used, and when an osmo-bsc is built against older libosmocore and then used at runtime against a newer libosmocore (which should be rare). Hence, the downside is acceptable, and by moving the new ID number to be ouside of the spec proto TS 48.008 range (4 bits), we make sure we don't have the same problem again in the future.

Related: SYS#5838 Fixes: ca33a71ca8eeaee98b1b53d5394b147a4ff0b429 Change-Id: Id25e563febdb7640174540136225f399515a0089 --- M include/osmocom/gsm/gsm0808_utils.h M include/osmocom/gsm/gsm23003.h M include/osmocom/gsm/protocol/gsm_08_08.h M src/gsm/gsm0808_utils.c M src/gsm/gsm23003.c M tests/gsm0808/gsm0808_test.c 6 files changed, 126 insertions(+), 4 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/24/27224/2