core: early out in handle_incoming_tx if already in pool or blockchain

src/cryptonote_core/cryptonote_core.cpp

@@ -496,6 +496,18 @@ namespace cryptonote
       return false;
     }
 
+    if(m_mempool.have_tx(tx_hash))
+    {
+      LOG_PRINT_L2("tx " << tx_hash << "already have transaction in tx_pool");
+      return true;
+    }
+
+    if(m_blockchain_storage.have_tx(tx_hash))
+    {
+      LOG_PRINT_L2("tx " << tx_hash << " already have transaction in blockchain");
+      return true;
+    }
+
     if(!check_tx_syntax(tx))
     {
       LOG_PRINT_L1("WRONG TRANSACTION BLOB, Failed to check tx " << tx_hash << " syntax, rejected");