From 8d6b6676c51843f5f5e9aecc344245b15b504fbd Mon Sep 17 00:00:00 2001
From: Robert Schmidt <robert.schmidt@openairinterface.org>
Date: Wed, 7 Aug 2024 16:50:35 +0200
Subject: [PATCH] Reorganize sequence of reestablishment checks
Reorganize the sequence of checks done in reestablishment to make it
more logical:
- check conditions of request (correct C-RNTI)
- check conditions of DU (has MIB/SIB1, MTC)
- check the UE, and from which DU it comes
This will also help to extend it towards reestablishment coming from
different DUs in the case of handover.
---
openair2/RRC/NR/rrc_gNB.c | 34 +++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/openair2/RRC/NR/rrc_gNB.c b/openair2/RRC/NR/rrc_gNB.c
index 14e84861a74..b884a2d8089 100644
--- a/openair2/RRC/NR/rrc_gNB.c
+++ b/openair2/RRC/NR/rrc_gNB.c
@@ -1130,6 +1130,13 @@ static void rrc_handle_RRCReestablishmentRequest(gNB_RRC_INST *rrc,
return;
}
+ // 3GPP TS 38.321 version 15.13.0 Section 7.1 Table 7.1-1: RNTI values
+ if (req->ue_Identity.c_RNTI < 0x1 || req->ue_Identity.c_RNTI > 0xffef) {
+ /* c_RNTI range error should not happen */
+ LOG_E(NR_RRC, "NR_RRCReestablishmentRequest c_RNTI %04lx range error, fallback to RRC setup\n", req->ue_Identity.c_RNTI);
+ goto fallback_rrc_setup;
+ }
+
if (du->mib == NULL || du->sib1 == NULL) {
/* we don't have MIB/SIB1 of the DU, and therefore cannot generate the
* Reestablishment (as we would need the SSB's ARFCN, which we cannot
@@ -1138,12 +1145,22 @@ static void rrc_handle_RRCReestablishmentRequest(gNB_RRC_INST *rrc,
goto fallback_rrc_setup;
}
+ if (du->mtc == NULL) {
+ // some UEs don't send MeasurementTimingConfiguration, so we don't know the
+ // SSB ARFCN and can't do reestablishment. handle it gracefully by doing
+ // RRC setup procedure instead
+ LOG_E(NR_RRC, "no MeasurementTimingConfiguration for this cell, cannot perform reestablishment\n");
+ ngap_cause = NGAP_CAUSE_RADIO_NETWORK_RELEASE_DUE_TO_NGRAN_GENERATED_REASON;
+ goto fallback_rrc_setup;
+ }
+
rnti_t old_rnti = req->ue_Identity.c_RNTI;
ue_context_p = rrc_gNB_get_ue_context_by_rnti(rrc, assoc_id, old_rnti);
if (ue_context_p == NULL) {
LOG_E(NR_RRC, "NR_RRCReestablishmentRequest without UE context, fallback to RRC setup\n");
goto fallback_rrc_setup;
}
+ gNB_RRC_UE_t *UE = &ue_context_p->ue_context;
const f1ap_served_cell_info_t *cell_info = &du->setup_req->cell[0].info;
if (physCellId != cell_info->nr_pci) {
@@ -1160,14 +1177,6 @@ static void rrc_handle_RRCReestablishmentRequest(gNB_RRC_INST *rrc,
goto fallback_rrc_setup;
}
- gNB_RRC_UE_t *UE = &ue_context_p->ue_context;
- // 3GPP TS 38.321 version 15.13.0 Section 7.1 Table 7.1-1: RNTI values
- if (req->ue_Identity.c_RNTI < 0x1 || req->ue_Identity.c_RNTI > 0xffef) {
- /* c_RNTI range error should not happen */
- LOG_E(NR_RRC, "NR_RRCReestablishmentRequest c_RNTI %04lx range error, fallback to RRC setup\n", req->ue_Identity.c_RNTI);
- goto fallback_rrc_setup;
- }
-
if (!UE->as_security_active) {
/* no active security context, need to restart entire connection */
LOG_E(NR_RRC, "UE requested Reestablishment without activated AS security\n");
@@ -1175,15 +1184,6 @@ static void rrc_handle_RRCReestablishmentRequest(gNB_RRC_INST *rrc,
goto fallback_rrc_setup;
}
- if (du->mtc == NULL) {
- // some UEs don't send MeasurementTimingConfiguration, so we don't know the
- // SSB ARFCN and can't do reestablishment. handle it gracefully by doing
- // RRC setup procedure instead
- LOG_E(NR_RRC, "no MeasurementTimingConfiguration for this cell, cannot perform reestablishment\n");
- ngap_cause = NGAP_CAUSE_RADIO_NETWORK_RELEASE_DUE_TO_NGRAN_GENERATED_REASON;
- goto fallback_rrc_setup;
- }
-
/* TODO: start timer in ITTI and drop UE if it does not come back */
// update with new RNTI, and update secondary UE association
--
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