Enable IP TUN interface configuration upon reception of PDU Session Establishment Accept NAS message

-User plane traffic validation with OAI UE and OAI CN:

-Downlink ping initiated from the CN is received at the IP interface of the UE. However it seems that there is some packet corruption preventing the generaration of ping reply.

-Uplink ping initiated from the UE reaches the OAI CN machine. However no ping reply is seen yet either.

openair2/LAYER2/nr_pdcp/nr_pdcp_oai_api.c

@@ -459,7 +459,8 @@ static void deliver_sdu_drb(void *_ue, nr_pdcp_entity_t *entity,
   int rb_id;
   int i;
 
-  if(IS_SOFTMODEM_NOS1){
+  if(UE_NAS_USE_TUN){
+    LOG_D(PDCP, "IP packet received, to be sent to UE TUN interface"); 
     len = write(nas_sock_fd[0], buf, size);
     if (len != size) {
       LOG_E(PDCP, "%s:%d:%s: fatal\n", __FILE__, __LINE__, __FUNCTION__);

openair3/NAS/NR_UE/nr_nas_msg_sim.c

@@ -38,7 +38,8 @@
 #include "aka_functions.h"
 #include "secu_defs.h"
 #include "PduSessionEstablishRequest.h"
-# include "intertask_interface.h"
+#include "intertask_interface.h"
+#include "openair2/RRC/NAS/nas_config.h"
 
 /*char netName[] = "5G:mnc093.mcc208.3gppnetwork.org";
 char imsi[] = "2089300007487";
@@ -57,6 +58,7 @@ const uint8_t opc[16] = {0xc4, 0x24, 0x49, 0x36, 0x3b, 0xba, 0xd0, 0x2b, 0x66, 0
 
 uint8_t  *registration_request_buf;
 uint32_t  registration_request_len;
+extern char *baseNetAddress; 
 
 static int nas_protected_security_header_encode(
   char                                       *buffer,
@@ -816,6 +818,16 @@ void *nas_nrue_task(void *args_p)
             LOG_I(NAS, "Send NAS_UPLINK_DATA_REQ message(PduSessionEstablishRequest)\n");
           }
         }
+        else if((pdu_buffer + 16) != NULL){
+          msg_type = *(pdu_buffer + 16);
+          if(msg_type == FGS_PDU_SESSION_ESTABLISHMENT_ACC){
+            sprintf(baseNetAddress, "%d.%d", *(pdu_buffer + 39),*(pdu_buffer + 40));
+            int third_octet = *(pdu_buffer + 41);
+            int fourth_octet = *(pdu_buffer + 42);
+            LOG_I(NAS, "Received PDU Session Establishment Accept\n");
+            nas_config(1,third_octet,fourth_octet,"ue");
+          }
+        }
 
         break;
       }

openair3/NAS/NR_UE/nr_nas_msg_sim.h

@@ -59,6 +59,7 @@
 
 // message type for 5GS session management
 #define FGS_PDU_SESSION_ESTABLISHMENT_REQ                  0b11000001 /* 193= 0xc1 */
+#define FGS_PDU_SESSION_ESTABLISHMENT_ACC                  0b11000010 /* 194= 0xc2 */
 
 #define INITIAL_REGISTRATION                               0b001