[AMF,SMF] Prevent mapped HPLMN SST to always be set

In case that mapped HPLMN SST was not set by the UE in the request to
Establish PDU Session, AMF/SMF would assume it is set to 0 (since the
recent change to allow SST value 0).

lib/nas/5gs/types.c

@@ -147,7 +147,8 @@ void ogs_nas_build_s_nssai(
         pos += 3;
     }
 
-    nas_s_nssai->buffer[pos++] = nas_s_nssai_ie->mapped_hplmn_sst;
+    if (nas_s_nssai_ie->mapped_hplmn_sst_presence)
+        nas_s_nssai->buffer[pos++] = nas_s_nssai_ie->mapped_hplmn_sst;
 
     if (nas_s_nssai_ie->mapped_hplmn_sd.v != OGS_S_NSSAI_NO_SD_VALUE) {
         v = ogs_htobe24(nas_s_nssai_ie->mapped_hplmn_sd);
@@ -166,14 +167,19 @@ void ogs_nas_build_s_nssai2(
 
     ogs_assert(nas_s_nssai);
     ogs_assert(s_nssai);
-    ogs_assert(mapped_hplmn);
 
     memset(&ie, 0, sizeof(ie));
 
     ie.sst = s_nssai->sst;
     ie.sd.v = s_nssai->sd.v;
-    ie.mapped_hplmn_sst = mapped_hplmn->sst;
+
-    ie.mapped_hplmn_sd.v = mapped_hplmn->sd.v;
+    if (mapped_hplmn) {
+        ie.mapped_hplmn_sst_presence = true;
+        ie.mapped_hplmn_sst = mapped_hplmn->sst;
+        ie.mapped_hplmn_sd.v = mapped_hplmn->sd.v;
+    } else {
+        ie.mapped_hplmn_sd.v = OGS_S_NSSAI_NO_SD_VALUE;
+    }
 
     ogs_nas_build_s_nssai(nas_s_nssai, &ie);
 }
@@ -237,8 +243,10 @@ int ogs_nas_parse_s_nssai(
         pos += 3;
     }
 
-    if (mapped_hplmn_sst)
+    if (mapped_hplmn_sst) {
         nas_s_nssai_ie->mapped_hplmn_sst = nas_s_nssai->buffer[pos++];
+        nas_s_nssai_ie->mapped_hplmn_sst_presence = true;
+    }
 
     if (mapped_hplmn_sd) {
         memcpy(&v, nas_s_nssai->buffer+pos, 3);

lib/nas/5gs/types.h

@@ -66,6 +66,7 @@ typedef struct ogs_nas_s_nssai_ie_s {
     uint8_t sst;
     ogs_uint24_t sd;
     uint8_t mapped_hplmn_sst;
+    bool mapped_hplmn_sst_presence;
     ogs_uint24_t mapped_hplmn_sd;
 } __attribute__ ((packed)) ogs_nas_s_nssai_ie_t;
 

src/amf/context.c

@@ -2265,6 +2265,7 @@ amf_sess_t *amf_sess_add(amf_ue_t *amf_ue, uint8_t psi)
 
     sess->s_nssai.sst = 0;
     sess->s_nssai.sd.v = OGS_S_NSSAI_NO_SD_VALUE;
+    sess->mapped_hplmn_presence = false;
     sess->mapped_hplmn.sst = 0;
     sess->mapped_hplmn.sd.v = OGS_S_NSSAI_NO_SD_VALUE;
 
@@ -2887,6 +2888,8 @@ bool amf_update_allowed_nssai(amf_ue_t *amf_ue)
 
                 allowed->sst = requested->sst;
                 allowed->sd.v = requested->sd.v;
+                allowed->mapped_hplmn_sst_presence =
+                        requested->mapped_hplmn_sst_presence;
                 allowed->mapped_hplmn_sst = requested->mapped_hplmn_sst;
                 allowed->mapped_hplmn_sd.v = requested->mapped_hplmn_sd.v;
 
@@ -2923,6 +2926,7 @@ bool amf_update_allowed_nssai(amf_ue_t *amf_ue)
 
                 allowed->sst = slice->s_nssai.sst;
                 allowed->sd.v = slice->s_nssai.sd.v;
+                allowed->mapped_hplmn_sst_presence = false;
                 allowed->mapped_hplmn_sst = 0;
                 allowed->mapped_hplmn_sd.v = OGS_S_NSSAI_NO_SD_VALUE;
 

src/amf/context.h

@@ -834,6 +834,7 @@ typedef struct amf_sess_s {
 
     ogs_s_nssai_t s_nssai;
     ogs_s_nssai_t mapped_hplmn;
+    bool mapped_hplmn_presence;
     char *dnn;
 
 } amf_sess_t;

src/amf/gmm-handler.c

@@ -1287,8 +1287,11 @@ int gmm_handle_ul_nas_transport(ran_ue_t *ran_ue, amf_ue_t *amf_ue,
                         if (ie.sst == amf_ue->slice[i].s_nssai.sst &&
                             ie.sd.v == amf_ue->slice[i].s_nssai.sd.v) {
 
-                            sess->mapped_hplmn.sst = ie.mapped_hplmn_sst;
+                            if (ie.mapped_hplmn_sst_presence) {
-                            sess->mapped_hplmn.sd.v = ie.mapped_hplmn_sd.v;
+                                sess->mapped_hplmn_presence = true;
+                                sess->mapped_hplmn.sst = ie.mapped_hplmn_sst;
+                                sess->mapped_hplmn.sd.v = ie.mapped_hplmn_sd.v;
+                            }
 
                             /* PASS */
 

src/amf/nsmf-build.c

@@ -133,9 +133,11 @@ ogs_sbi_request_t *amf_nsmf_pdusession_build_create_sm_context(
     sNssai.sd = ogs_s_nssai_sd_to_string(sess->s_nssai.sd);
     SmContextCreateData.s_nssai = &sNssai;
 
-    hplmnSnssai.sst = sess->mapped_hplmn.sst;
+    if (sess->mapped_hplmn_presence) {
-    hplmnSnssai.sd = ogs_s_nssai_sd_to_string(sess->mapped_hplmn.sd);
+        hplmnSnssai.sst = sess->mapped_hplmn.sst;
-    SmContextCreateData.hplmn_snssai = &hplmnSnssai;
+        hplmnSnssai.sd = ogs_s_nssai_sd_to_string(sess->mapped_hplmn.sd);
+        SmContextCreateData.hplmn_snssai = &hplmnSnssai;
+    }
 
     SmContextCreateData.guami = ogs_sbi_build_guami(amf_ue->guami);
     if (!SmContextCreateData.guami) {

src/smf/context.h

@@ -379,6 +379,7 @@ typedef struct smf_sess_s {
     /* S_NSSAI */
     ogs_s_nssai_t s_nssai;
     ogs_s_nssai_t mapped_hplmn;
+    bool mapped_hplmn_presence;
 
     /* PDN Configuration */
     ogs_session_t session;

src/smf/gsm-build.c

@@ -186,7 +186,8 @@ ogs_pkbuf_t *gsm_build_pdu_session_establishment_accept(smf_sess_t *sess)
     /* S-NSSAI */
     pdu_session_establishment_accept->presencemask |=
         OGS_NAS_5GS_PDU_SESSION_ESTABLISHMENT_ACCEPT_S_NSSAI_PRESENT;
-    ogs_nas_build_s_nssai2(nas_s_nssai, &sess->s_nssai, &sess->mapped_hplmn);
+    ogs_nas_build_s_nssai2(nas_s_nssai, &sess->s_nssai,
+        (sess->mapped_hplmn_presence) ? &sess->mapped_hplmn : NULL);
 
     /* QoS flow descriptions */
     memset(&qos_flow_description, 0, sizeof(qos_flow_description));

src/smf/nsmf-handler.c

@@ -236,6 +236,7 @@ bool smf_nsmf_handle_create_sm_context(
     sess->s_nssai.sst = sNssai->sst;
     sess->s_nssai.sd = ogs_s_nssai_sd_from_string(sNssai->sd);
     if (SmContextCreateData->hplmn_snssai) {
+        sess->mapped_hplmn_presence = true;
         sess->mapped_hplmn.sst = SmContextCreateData->hplmn_snssai->sst;
         sess->mapped_hplmn.sd = ogs_s_nssai_sd_from_string(
                                     SmContextCreateData->hplmn_snssai->sd);

tests/common/context.c

@@ -1174,6 +1174,7 @@ test_ue_t *test_ue_add_by_suci(
 
             s_nssai->sst = 0;
             s_nssai->sd.v = OGS_S_NSSAI_NO_SD_VALUE;
+            s_nssai->mapped_hplmn_sst_presence = false;
             s_nssai->mapped_hplmn_sst = 0;
             s_nssai->mapped_hplmn_sd.v = OGS_S_NSSAI_NO_SD_VALUE;
 

tests/slice/same-dnn-test.c

@@ -426,6 +426,8 @@ static void test2_func(abts_case *tc, void *data)
         sst = 2;
     test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].
         sd.v = OGS_S_NSSAI_NO_SD_VALUE;
+    test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].
+        mapped_hplmn_sst_presence = false;
     test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].
         mapped_hplmn_sst = 0;
     test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].
@@ -436,6 +438,8 @@ static void test2_func(abts_case *tc, void *data)
         sst = 3;
     test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].
         sd.v = 0x000080;
+    test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].
+        mapped_hplmn_sst_presence = false;
     test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].
         mapped_hplmn_sst = 0;
     test_ue->requested_nssai.s_nssai[test_ue->requested_nssai.num_of_s_nssai].