entry keep alive flag set to true if entry already exists. (#1675)

Author: deepakvenugopal

source/6LoWPAN/Thread/thread_extension_bbr.c

@@ -776,13 +776,13 @@ static int thread_extension_bbr_dua_cb(int8_t service_id, uint8_t source_address
 
     tr_debug("DUA.req addr:%s ml_eid:%s", trace_array(addr_data_ptr, addr_len), trace_array(ml_eid_ptr, ml_eid_len));
 
-    entry_keep_alive = true;
+    entry_keep_alive = false;
     // TODO add ml_eid to structure saved in info pointer to detect duplicates
     if (thread_bbr_nd_entry_find(this->interface_id, addr_data_ptr) == 0) {
-        entry_keep_alive = false;
+        entry_keep_alive = true;
     }
 
-    if (thread_bbr_nd_entry_add(this->interface_id, addr_data_ptr, 0xFFFFFFFF, NULL, ml_eid_ptr) == -1) {
+    if (thread_bbr_nd_entry_add(this->interface_id, addr_data_ptr, 0xFFFFFFFF, NULL, ml_eid_ptr) != 0) {
         bbr_status = THREAD_BBR_STATUS_RESOURCE_SHORTAGE;
         goto send_response;
     }