Add basic E2 agent through git submodule

- Add E2 agent that leverages FlexRIC e2ap library
- Add documentation in openair2/E2AP/README.md
- Currently, statistics exported are random

executables/nr-softmodem.c

@@ -82,6 +82,12 @@ unsigned short config_frames[4] = {2,9,11,13};
 #include "openair2/E1AP/e1ap_common.h"
 #include "openair2/E1AP/e1ap_api.h"
 
+#ifdef E2_AGENT
+#include "openair2/E2AP/flexric/src/agent/e2_agent_api.h"
+#include "openair2/E2AP/RAN_FUNCTION/init_ran_func.h"
+#endif
+
+
 pthread_cond_t nfapi_sync_cond;
 pthread_mutex_t nfapi_sync_mutex;
 int nfapi_sync_var=-1; //!< protected by mutex \ref nfapi_sync_mutex
@@ -683,6 +689,53 @@ int main( int argc, char **argv ) {
 
   config_sync_var=0;
 
+
+
+
+#ifdef E2_AGENT
+
+//////////////////////////////////
+//////////////////////////////////
+//// Init the E2 Agent
+ 
+  sm_io_ag_ran_t io = init_ran_func_ag();
+  fr_args_t args = init_fr_args(0, NULL);
+  
+  // OAI Wrapper 
+  e2_agent_args_t oai_args = RCconfig_NR_E2agent();
+  if(oai_args.sm_dir != NULL)
+    memcpy(args.libs_dir, oai_args.sm_dir, 128);
+
+  sleep(1);
+  const gNB_RRC_INST* rrc = RC.nrrrc[0];
+  assert(rrc != NULL && "rrc cannot be NULL");
+
+  const int mcc = rrc->configuration.mcc[0];
+  const int mnc = rrc->configuration.mnc[0];
+  const int mnc_digit_len = rrc->configuration.mnc_digit_length[0];
+  const ngran_node_t node_type = rrc->node_type;
+  int nb_id = 0;
+  int cu_du_id = 0;
+  if (node_type == ngran_gNB) {
+    nb_id = rrc->configuration.cell_identity;
+  } else if (node_type == ngran_gNB_DU) {
+    cu_du_id = rrc->node_id + 1; // Hack to avoid been 0
+    nb_id = rrc->configuration.cell_identity;
+  } else if (node_type == ngran_gNB_CU) {
+    cu_du_id = rrc->node_id + 1;
+    nb_id = rrc->configuration.cell_identity;
+  } else {
+    LOG_E(NR_RRC, "not supported ran type detect\n");
+  }
+     
+  printf("[E2 NODE]: mcc = %d mnc = %d mnc_digit = %d nb_id = %d \n", mcc, mnc, mnc_digit_len, nb_id);
+
+  init_agent_api(mcc, mnc, mnc_digit_len, nb_id, cu_du_id, node_type, io, &args);
+//   }
+
+#endif // E2_AGENT
+
+
   if (NFAPI_MODE==NFAPI_MODE_PNF) {
     wait_nfapi_init("main?");
   }