--- embedaddon/iftop/hash.c	2012/02/21 16:57:34	1.1.1.1
+++ embedaddon/iftop/hash.c	2016/10/18 14:04:50	1.1.1.2
@@ -76,6 +76,11 @@ hash_status_enum hash_find(hash_type* hash_table, void
 
 hash_status_enum hash_next_item(hash_type* hash_table, hash_node_type** ppnode) {
     int i;
+
+    if (hash_table == 0) {
+      return HASH_STATUS_KEY_NOT_FOUND;
+    }
+
     if(*ppnode != NULL) {
         if((*ppnode)->next != NULL) {
             *ppnode = (*ppnode)->next;
@@ -101,6 +106,11 @@ hash_status_enum hash_next_item(hash_type* hash_table,
 void hash_delete_all(hash_type* hash_table) {
     int i;
     hash_node_type *n, *nn;
+
+    if(hash_table == 0) {
+      return;
+    }
+
     for(i = 0; i < hash_table->size; i++) {
         n = hash_table->table[i];
         while(n != NULL) {