lynxis lazus has submitted this change. (
https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/38397?usp=email )
Change subject: SGSN: BSSGP_ConnHdlr: GMM Service Request: handle PMM IDLE UE
correct
......................................................................
SGSN: BSSGP_ConnHdlr: GMM Service Request: handle PMM IDLE UE correct
24.008: 4.7.13.3: explicitly mention the completion of the low layer security
to be an implicit
Security Command Accept if the UE is in PMM Idle.
Extend the as_service_request() to handle both cases when UE is in PMM-IDLE as
well in
PMM-CONNECTED.
Change-Id: I29237997e414aea80f254247da54f909410a4b36
---
M sgsn/BSSGP_ConnHdlr.ttcn
1 file changed, 30 insertions(+), 6 deletions(-)
Approvals:
pespin: Looks good to me, but someone else must approve
laforge: Looks good to me, approved
Jenkins Builder: Verified
diff --git a/sgsn/BSSGP_ConnHdlr.ttcn b/sgsn/BSSGP_ConnHdlr.ttcn
index 2a434aa..82788f5 100644
--- a/sgsn/BSSGP_ConnHdlr.ttcn
+++ b/sgsn/BSSGP_ConnHdlr.ttcn
@@ -618,24 +618,48 @@
}
}
-/* Iu only */
-altstep as_service_request(integer ran_index := 0) runs on BSSGP_ConnHdlr {
+/* Iu only
+ *
+ * Handle a service request for a UE in PMM_IDLE or PMM_CONNECTED depending on
exp_service_acc
+ * Depending on the PMM state:
+ * a) PMM_IDLE: The network will do a SecurityModeCommand on Iu, which the UE
will treat as an implicit Service Accept
+ * b) PMM_CONNECTED: The Iu connection is already secured, do an explicit
Service Accept
+ *
+ * NOTE: The old osmo-sgsn will always respond with a ServiceAccept even when
the spec is clear this is not needed.
+ */
+altstep as_service_request(boolean exp_service_acc := true, integer ran_index
:= 0) runs on BSSGP_ConnHdlr {
var PDU_DTAP_PS_MT mt;
- [] BSSAP.receive(tr_PDU_DTAP_PS_MT(tr_GMM_SERVICE_ACC)) -> value mt {
+ [exp_service_acc] BSSAP.receive(tr_PDU_DTAP_PS_MT(tr_GMM_SERVICE_ACC))
-> value mt {
setverdict(pass);
}
+ [not exp_service_acc]
BSSAP.receive(tr_PDU_DTAP_PS_MT(tr_GMM_SERVICE_ACC)) -> value mt {
+ setverdict(fail, "Unexpected Service Accept");
+ mtc.stop;
+ }
[] BSSAP.receive(tr_PDU_DTAP_PS_MT(tr_GMM_SERVICE_REJ)) {
setverdict(fail, "Unexpected Service Reject");
mtc.stop;
}
+ /* 24.008 4.7.13.3: a SecurityModeCommand is an implicit Service Accept
if UE was in PMM-IDLE */
[] BSSAP.receive(tr_RANAP_SecurityModeCmd(uia_algs := ?,
uia_key :=
oct2bit(g_pars.vec.ik),
key_sts := ?)) {
var IntegrityProtectionAlgorithm uia_chosen := 0; /* 0 =
standard_UMTS_integrity_algorithm_UIA1 */
BSSAP.send(ts_RANAP_SecurityModeComplete(uia_chosen));
- BSSAP.receive(tr_RANAP_CommonId(imsi_hex2oct(g_pars.imsi)))
- repeat;
+ if (not exp_service_acc) {
+ /* Because we stop processing early, we need to consume
the CommonID */
+
BSSAP.receive(tr_RANAP_CommonId(imsi_hex2oct(g_pars.imsi)));
+ setverdict(pass);
+ } else {
+ /* This repeat would be wrong if you follow the spec
correct. Because:
+ * a) the UE is in PMM Idle and in this case the
exp_service_acc would be true
+ * b) the UE is in PMM Connected and in this case the
Iu Connection should be already secure and this would fail.
+ * The old osmo-sgsn is doing for UE in PMM Idle both a
Security Command and a Service Accept, after the VLR change, the
+ * osmo-sgsn will follow the spec correct.
+ */
+ repeat;
+ }
}
}
@@ -671,7 +695,7 @@
}
alt {
- [] as_service_request(ran_index) { setverdict(pass); }
+ [] as_service_request(exp_service_acc := true, ran_index := ran_index)
{ setverdict(pass); }
[] BSSAP.receive { repeat; }
[] T.timeout {
Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail,
--
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Gerrit-MessageType: merged
Gerrit-Project: osmo-ttcn3-hacks
Gerrit-Branch: master
Gerrit-Change-Id: I29237997e414aea80f254247da54f909410a4b36
Gerrit-Change-Number: 38397
Gerrit-PatchSet: 8
Gerrit-Owner: lynxis lazus <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: lynxis lazus <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
