From 2ef2da54abd537cc131aa9815a0d1bb91d0987e0 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Mon, 18 Dec 2017 01:23:42 +0100 Subject: cosmetic prep: tell vlr_ops.set_ciph_mode() whether UMTS AKA is used In case of UMTS AKA, the Kc for ciphering must be derived from the 3G auth tokens. tuple->vec.kc was calculated from the GSM algorithm and is not necessarily a match for the UMTS AKA tokens. To decide (in an upcoming patch) whether to use UMTS AKA derived Kc or the Kc from the auth vector, the set_ciph_mode() from vlr_ops needs to know whether UMTS AKA is being used. This could possibly derived from the msc_conn_ref, but all flags are already available in the vlr_lu_fsm and vlr_access_req_fsm. Hence add a umts_aka flag to the set_ciph_mode() callback invocation. The VLR FSMs thus decide whether UMTS AKA or GSM AKA is to be used during Ciphering Mode Command, which makes more sense than re-implementing the same decision process in the MSC. I considered placing the Kc derivation in vlr_set_ciph_mode() and only tell the MSC's set_ciph_mode() implementation the precise keys it should use, but the RAN particulars, and whether a Kc is used at all, rather belong with the MSC. Related: OS#2745 Prepares: If04e405426c55a81341747a9b450a69188525d5c Change-Id: I983c48347faf4ee1b405d8174b4e006c904157cf --- include/osmocom/msc/vlr.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/osmocom/msc/vlr.h') diff --git a/include/osmocom/msc/vlr.h b/include/osmocom/msc/vlr.h index df7d3548b..b6256086c 100644 --- a/include/osmocom/msc/vlr.h +++ b/include/osmocom/msc/vlr.h @@ -207,7 +207,7 @@ struct vlr_ops { int (*tx_cm_serv_rej)(void *msc_conn_ref, enum vlr_proc_arq_result result); int (*set_ciph_mode)(void *msc_conn_ref, enum vlr_ciph ciph_mode, - bool retrieve_imeisv); + bool umts_aka, bool retrieve_imeisv); /* UTRAN: send Common Id (when auth+ciph are complete) */ int (*tx_common_id)(void *msc_conn_ref); @@ -433,6 +433,7 @@ int vlr_set_ciph_mode(struct vlr_instance *vlr, struct osmo_fsm_inst *fi, void *msc_conn_ref, enum vlr_ciph ciph_mode, + bool umts_aka, bool retrieve_imeisv); bool vlr_use_umts_aka(struct osmo_auth_vector *vec, bool is_r99); -- cgit v1.2.3