Fix bug in TAI sorting, limit the TAI list for UE

Signed-off-by: Ulas Kozat <kozat@fb.com>
magma · May 5, 2021 · 15a4948 · 15a4948
1 parent 7d33d4a
commit 15a4948
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Showing 2 changed files with 18 additions and 2 deletions.
diff --git a/lte/gateway/c/oai/tasks/mme_app/mme_config.c b/lte/gateway/c/oai/tasks/mme_app/mme_config.c
@@ -763,6 +763,11 @@ int mme_config_parse_file(mme_config_t* config_pP) {
                 config_pP->served_tai.plmn_mnc[i];
             config_pP->served_tai.plmn_mnc[i] = swap16;
 
+            swap16 = config_pP->served_tai.plmn_mnc_len[i - 1];
+            config_pP->served_tai.plmn_mnc_len[i - 1] =
+                config_pP->served_tai.plmn_mnc_len[i];
+            config_pP->served_tai.plmn_mnc_len[i] = swap16;
+
             swap16                           = config_pP->served_tai.tac[i - 1];
             config_pP->served_tai.tac[i - 1] = config_pP->served_tai.tac[i];
             config_pP->served_tai.tac[i]     = swap16;

diff --git a/lte/gateway/c/oai/tasks/nas/api/mme/mme_api.c b/lte/gateway/c/oai/tasks/nas/api/mme/mme_api.c
@@ -107,8 +107,9 @@ int mme_api_get_emm_config(
       LOG_NAS, "Number of GUMMEIs supported = %d\n", mme_config_p->gummei.nb);
 
   config->tai_list.numberoflists = 0;
-  // TODO actually we support only one partial TAI list.
-  // reminder mme_config_p->served_tai is sorted in ascending order of TAIs
+  // We can store 16 TAIs per list and have 16 partial lists maximum
+  // As per TS 124.301 V15.4.0 Section 9.9.3.33, we will be sending at most
+  // 16 TAIs for which UE data is set during
   switch (mme_config_p->served_tai.list_type) {
     case TRACKING_AREA_IDENTITY_LIST_TYPE_ONE_PLMN_CONSECUTIVE_TACS: {
       int tai_list_i = 0, tac_i = 0;
@@ -529,6 +530,16 @@ int mme_api_new_guti(
             0, "BAD TAI list configuration, unknown TAI list type %u",
             _emm_data.conf.tai_list.partial_tai_list[i].typeoflist);
     }
+
+    // TS 124.301 V15.4.0 Section 9.9.3.33:
+    // "The Tracking area identity list is a type 4 information element,
+    // with a minimum length of 8 octets and a maximum length of 98 octets.
+    // The list can contain a maximum of 16 different tracking area identities."
+    // We will limit the number to 1 partial list which can have maximum of 16
+    // TAIs.
+    if (j == 1) {
+      break;  // for loop
+    }
   }
   tai_list->numberoflists = j;
   OAILOG_INFO(