Enable multiple RC subscriptions

  - create hash table to save riq_req_id (key) and array of ran_param_id(s) (values), per each subscription
  - create RB tree to store list of riq_req_id(s) for each ran_param_id
    => when the async event occurs, it is easier and faster to search per ran_param_id and send the indication message to all xApps (riq_req_id(s)) subscribed to the same ran_param_id
  - it is important to mention that both data structures need to be maintained, especially when unsubscription occurs (free_aperiodic_subscription)

openair2/E2AP/RAN_FUNCTION/O-RAN/ran_func_rc.c

@@ -30,12 +30,93 @@
 #include <stdio.h>
 #include <pthread.h>
 #include <unistd.h>
+#include "common/utils/hashtable/hashtable.h"
 #include "common/utils/assertions.h"
 #include "common/ran_context.h"
 
-static const int rrc_state_changed_to = 202;
-static bool subs_rrc_state_change = false;
-static uint32_t riq_req_id = 0;
+#define MAX_NUM_RIQ_REQ_ID 64
+
+typedef enum {
+  RRC_STATE_CHANGED_TO_E2SM_RC_RAN_PARAM_ID = 202,   // 8.2.4  RAN Parameters for Report Service Style 4
+
+  END_E2SM_RC_RAN_PARAM_ID
+} ran_param_id_e;
+
+typedef struct rb_riq_req_id_s {
+  RB_ENTRY(rb_riq_req_id_s) entries;
+  uint32_t riq_req_id;
+} rb_riq_req_id_t;
+
+typedef struct {
+  RB_HEAD(riq_id_2_param_id, rb_riq_req_id_s) arr[END_E2SM_RC_RAN_PARAM_ID];
+  hash_table_t* riq_id_2_param_id_mapping;
+} rc_subs_data_t;
+
+int riq_req_id_compare(struct rb_riq_req_id_s *c1_pP, struct rb_riq_req_id_s *c2_pP)
+{
+  if (c1_pP->riq_req_id > c2_pP->riq_req_id) {
+    return 1;
+  }
+
+  if (c1_pP->riq_req_id < c2_pP->riq_req_id) {
+    return -1;
+  }
+
+  return 0;
+}
+
+RB_GENERATE(riq_id_2_param_id, rb_riq_req_id_s, entries, riq_req_id_compare);
+
+typedef struct{
+  size_t len;
+  ran_param_id_e* ran_param_id;
+} arr_ran_param_id_t;
+
+static rc_subs_data_t rc_subs_data = {0};
+static pthread_mutex_t rc_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static void init_rc_subs_data(void)
+{
+  pthread_mutex_lock(&rc_mutex);
+  // Initialize RB tree
+  for (size_t i = 0; i < END_E2SM_RC_RAN_PARAM_ID; i++) {
+    RB_INIT(&rc_subs_data.arr[i]);
+  }
+
+  // Initialize hash table
+  DevAssert(rc_subs_data.riq_id_2_param_id_mapping == NULL);
+  rc_subs_data.riq_id_2_param_id_mapping = hashtable_create(MAX_NUM_RIQ_REQ_ID, NULL, free);
+  assert(rc_subs_data.riq_id_2_param_id_mapping != NULL && "Memory exhausted");
+  pthread_mutex_unlock(&rc_mutex);
+}
+
+static void insert_rc_subs_data(uint32_t riq_req_id, arr_ran_param_id_t* arr_ran_param_id)
+{
+  pthread_mutex_lock(&rc_mutex);
+
+  // Insert in hash table
+  DevAssert(rc_subs_data.riq_id_2_param_id_mapping != NULL);
+  uint64_t key = riq_req_id;
+  // Check if the subscription already exists
+  if (hashtable_is_key_exists(rc_subs_data.riq_id_2_param_id_mapping, key) == HASH_TABLE_OK) {
+    pthread_mutex_unlock(&rc_mutex);
+    return;
+  }
+  void* value = (void*)arr_ran_param_id;
+  hashtable_rc_t ret = hashtable_insert(rc_subs_data.riq_id_2_param_id_mapping, key, value);
+  assert(ret == HASH_TABLE_OK  && "Hash table not ok");
+
+  // Insert in RB tree
+  for (size_t i = 0; i < arr_ran_param_id->len; i++) {
+    struct rb_riq_req_id_s *node = (struct rb_riq_req_id_s *)malloc(sizeof(struct rb_riq_req_id_s));
+    assert(node != NULL);
+
+    node->riq_req_id = riq_req_id;
+    RB_INSERT(riq_id_2_param_id, &rc_subs_data.arr[arr_ran_param_id->ran_param_id[i]], node);
+  }
+
+  pthread_mutex_unlock(&rc_mutex);
+}
 
 static ue_id_e2sm_t fill_ue_id_data(const gNB_RRC_UE_t *rrc_ue_context)
 {
@@ -88,7 +169,7 @@ static seq_ran_param_t fill_rrc_state_change_seq_ran(const rc_sm_rrc_state_e rrc
 {
   seq_ran_param_t seq_ran_param = {0};
 
-  seq_ran_param.ran_param_id = rrc_state_changed_to;
+  seq_ran_param.ran_param_id = RRC_STATE_CHANGED_TO_E2SM_RC_RAN_PARAM_ID;
   seq_ran_param.ran_param_val.type = ELEMENT_KEY_FLAG_FALSE_RAN_PARAMETER_VAL_TYPE;
   seq_ran_param.ran_param_val.flag_false = calloc(1, sizeof(ran_parameter_value_t));
   assert(seq_ran_param.ran_param_val.flag_false != NULL && "Memory exhausted");
@@ -132,15 +213,22 @@ static rc_ind_data_t* fill_ue_rrc_state_change(const gNB_RRC_UE_t *rrc_ue_contex
   return rc_ind;
 }
 
-
 void signal_rrc_state_changed_to(const gNB_RRC_UE_t *rrc_ue_context, const rc_sm_rrc_state_e rrc_state)
-{
-  AssertFatal(subs_rrc_state_change == true, "xApp should be subscribed to E2 node before sending the RIC INDICATION Message\n");
+{ 
+  pthread_mutex_lock(&rc_mutex);
+  if (rc_subs_data.riq_id_2_param_id_mapping == NULL)
+    return;
   
-  rc_ind_data_t* rc_ind_data = fill_ue_rrc_state_change(rrc_ue_context, rrc_state);
+  struct rb_riq_req_id_s *currentNode;
+  RB_FOREACH(currentNode, riq_id_2_param_id, &rc_subs_data.arr[RRC_STATE_CHANGED_TO_E2SM_RC_RAN_PARAM_ID]) {
+    rc_ind_data_t* rc_ind_data = fill_ue_rrc_state_change(rrc_ue_context, rrc_state);
 
-  async_event_agent_api(riq_req_id, rc_ind_data);
-  printf("Event for RIC Req ID %u generated\n", riq_req_id);
+    // Needs review: memory ownership of the type rc_ind_data_t is transferred to the E2 Agent. Bad
+    async_event_agent_api(currentNode->riq_req_id, rc_ind_data);
+    printf("Event for RIC Req ID %u generated\n", currentNode->riq_req_id);
+  }
+  
+  pthread_mutex_unlock(&rc_mutex);
 }
 
 bool read_rc_sm(void* data)
@@ -158,6 +246,8 @@ void read_rc_setup_sm(void* data)
 //  assert(data->type == RAN_CTRL_V1_3_AGENT_IF_E2_SETUP_ANS_V0);
   rc_e2_setup_t* rc = (rc_e2_setup_t*)data;
   rc->ran_func_def = fill_rc_ran_func_def();
+
+  init_rc_subs_data();
 }
 
 sm_ag_if_ans_t write_ctrl_rc_sm(void const* data)
@@ -205,14 +295,34 @@ sm_ag_if_ans_t write_ctrl_rc_sm(void const* data)
   return ans;
 }
 
+static void free_aperiodic_subscription(uint32_t riq_req_id)
+{
+  pthread_mutex_lock(&rc_mutex);
+  DevAssert(rc_subs_data.riq_id_2_param_id_mapping != NULL);
+
+  // Remove riq_req_id with its ran_param_id(s) from hash table
+  uint64_t key = riq_req_id;
+  hashtable_rc_t ret = hashtable_remove(rc_subs_data.riq_id_2_param_id_mapping, key);
+  assert(ret == HASH_TABLE_OK  && "Hash table not ok");
+  
+  // Remove riq_req_id from each tree of ran_param_id(s), if subscribed
+  rb_riq_req_id_t *node = calloc(1, sizeof(rb_riq_req_id_t));
+  assert(node != NULL);
+  node->riq_req_id = riq_req_id;
+  for (size_t i = 0; i < END_E2SM_RC_RAN_PARAM_ID; i++) {
+    if (rc_subs_data.arr[i].rbh_root == NULL)
+      continue;
+    RB_REMOVE(riq_id_2_param_id, &rc_subs_data.arr[i], node);
+  }
+  pthread_mutex_unlock(&rc_mutex);
+}
+
 sm_ag_if_ans_t write_subs_rc_sm(void const* src)
 {
   assert(src != NULL); // && src->type == RAN_CTRL_SUBS_V1_03);
 
   wr_rc_sub_data_t* wr_rc = (wr_rc_sub_data_t*)src;
 
-  riq_req_id = wr_rc->ric_req_id;  // store the ric_req_id to generate asynchronous event
-
   assert(wr_rc->rc.ad != NULL && "Cannot be NULL");
 
   // 9.2.1.2  RIC ACTION DEFINITION IE
@@ -221,13 +331,15 @@ sm_ag_if_ans_t write_subs_rc_sm(void const* src)
   case FORMAT_1_E2SM_RC_ACT_DEF: {
     // Parameters to be Reported List
     // [1-65535]
-    for(size_t i = 0; i < wr_rc->rc.ad->frmt_1.sz_param_report_def; i++) {
-      if (wr_rc->rc.ad->frmt_1.param_report_def[i].ran_param_id == rrc_state_changed_to) {
-        subs_rrc_state_change = true;
-      } else {
-        AssertFatal(wr_rc->rc.ad->frmt_1.param_report_def[i].ran_param_id == rrc_state_changed_to, "RAN Parameter ID %d not yet implemented\n", wr_rc->rc.ad->frmt_1.param_report_def[i].ran_param_id);
-      }
+    arr_ran_param_id_t* arr_values = calloc(1, sizeof(arr_ran_param_id_t));
+    assert(arr_values != NULL && "Memory exhausted");
+    arr_values->len = wr_rc->rc.ad->frmt_1.sz_param_report_def;
+    arr_values->ran_param_id = calloc(arr_values->len, sizeof(ran_param_id_e));
+    
+    for(size_t i = 0; i < arr_values->len; i++) {    
+      arr_values->ran_param_id[i] = wr_rc->rc.ad->frmt_1.param_report_def[i].ran_param_id;
     }
+    insert_rc_subs_data(wr_rc->ric_req_id, arr_values);
     break;
   }
   
@@ -235,7 +347,9 @@ sm_ag_if_ans_t write_subs_rc_sm(void const* src)
     AssertFatal(wr_rc->rc.ad->format == FORMAT_1_E2SM_RC_ACT_DEF, "Action Definition Format %d not yet implemented", wr_rc->rc.ad->format);
   }
 
-  sm_ag_if_ans_t ans = {0}; 
+  sm_ag_if_ans_t ans = {.type = SUBS_OUTCOME_SM_AG_IF_ANS_V0};
+  ans.subs_out.type = APERIODIC_SUBSCRIPTION_FLRC;
+  ans.subs_out.aper.free_aper_subs = free_aperiodic_subscription;
 
   return ans;
 }