emergency call: Support MobileIdentity=IMEI when no IMSI is used in the phone
See 3GPP TS 24.008 section 10.5.1.4 "Mobile Identity":
"For emergency call establishment and re-establishment the mobile station shall select the mobile identity type with the following priority" [...] -IMEI: he IMEI shall be used in cases where no SIM/USIM is available or the SIM/USIM is considered as not valid by the mobile station or no IMSI or TMSI is available."
However, right now, bsc_compl_l3() calls osmo_mobile_identity_decode_from_l3() and bsc_subscr_find_or_create_by_mi() but the later doesn't support parsing GSM_MI_TYPE_IMEI or GSM_MI_TYPE_IMEISV.
As of now, we carry on with conn if no subscr is created, but ideally that should change in the future and reject the conn (see bsc_compl_l3() comments in code).
Ideally we should create a TTCN3 test in BSC_Tests to validate everything works fine before/after implementing that case.
On Mon, Jan 02, 2023 at 04:09:39PM +0000, pespin wrote:
bsc_compl_l3() is also passing "mi" to function bsc_find_msc(), we may need to update that function too to handle GSM_MI_TYPE_IMEI
That is not necessary -- bsc_find_msc() uses a TMSI mi if present to extract the NRI indicating a previously selected MSC. For all other mi types (when there is no NRI), it uses the next MSC by round robin.
- Status changed from New to Feedback
- % Done changed from 0 to 90
The related code should be implemented and tested with the patches previously submitted plus this one:
https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/30847 bsc: TC_assignment_emerg_setup_allow(_imei): Test full voice establishment