diff --git a/Makefile b/Makefile
index d0eca05..ccd016e 100644
--- a/Makefile
+++ b/Makefile
@@ -25,7 +25,6 @@ CPPFLAGS += -DEXECUTOR_PATH=\"${EXECUTOR_PATH}\"
 
 
 LIBIFUPDOWN_SRC = \
-	libifupdown/compar.c \
 	libifupdown/list.c \
 	libifupdown/dict.c \
 	libifupdown/interface.c \
diff --git a/libifupdown/compar.c b/libifupdown/compar.c
deleted file mode 100644
index 8705404..0000000
--- a/libifupdown/compar.c
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * libifupdown/compar.c
- * Purpose: comparators
- *
- * Copyright (c) 2020 Maximilian Wilhelm <max@sdn.clinic>
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * This software is provided 'as is' and without any warranty, express or
- * implied.  In no event shall the authors be liable for any damages arising
- * from the use of this software.
- */
-
-#include <string.h>
-#include "libifupdown/compar.h"
-
-int
-compar_str (const void *a, const void *b)
-{
-	const char *str_a = (const char *)a;
-	const char *str_b = (const char *)b;
-
-	return strcmp (str_a, str_b);
-}
diff --git a/libifupdown/compar.h b/libifupdown/compar.h
deleted file mode 100644
index 8652a26..0000000
--- a/libifupdown/compar.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * libifupdown/compar.h
- * Purpose: Comparators
- *
- * Copyright (c) 2020 Maximilian Wilhelm <max@sdn.clinic>
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * This software is provided 'as is' and without any warranty, express or
- * implied.  In no event shall the authors be liable for any damages arising
- * from the use of this software.
- */
-
-#ifndef LIBIFUPDOWN_COMPAR_H__GUARD
-#define LIBIFUPDOWN_COMPAR_H__GUARD
-
-int compar_str (const void *a, const void *b);
-
-#endif
diff --git a/libifupdown/dict.c b/libifupdown/dict.c
index 3f5b1e1..4906f26 100644
--- a/libifupdown/dict.c
+++ b/libifupdown/dict.c
@@ -53,7 +53,7 @@ lif_dict_add(struct lif_dict *dict, const char *key, void *data)
 
 struct lif_dict_entry *
 lif_dict_add_once(struct lif_dict *dict, const char *key, void *data,
-                  int (*compar)(const void *, const void *))
+                  lif_dict_cmp_t compar)
 {
 	struct lif_list *existing = lif_dict_find_all(dict, key);
 	if (existing != NULL)
diff --git a/libifupdown/dict.h b/libifupdown/dict.h
index 2332c05..9a48ad2 100644
--- a/libifupdown/dict.h
+++ b/libifupdown/dict.h
@@ -35,10 +35,12 @@ struct lif_dict_entry {
 #define LIF_DICT_FOREACH_SAFE(iter, iter_next, dict) \
 	LIF_LIST_FOREACH_SAFE((iter), (iter_next), (dict)->list.head)
 
+typedef int (*lif_dict_cmp_t)(const void *, const void *);
+
 extern void lif_dict_init(struct lif_dict *dict);
 extern void lif_dict_fini(struct lif_dict *dict);
 extern struct lif_dict_entry *lif_dict_add(struct lif_dict *dict, const char *key, void *data);
-extern struct lif_dict_entry *lif_dict_add_once(struct lif_dict *dict, const char *key, void *data, int (*compar)(const void *, const void *));
+extern struct lif_dict_entry *lif_dict_add_once(struct lif_dict *dict, const char *key, void *data, lif_dict_cmp_t compar);
 extern struct lif_dict_entry *lif_dict_find(struct lif_dict *dict, const char *key);
 extern struct lif_list *lif_dict_find_all(struct lif_dict *dict, const char *key);
 extern void lif_dict_delete(struct lif_dict *dict, const char *key);
diff --git a/libifupdown/interface-file.c b/libifupdown/interface-file.c
index 205c920..c451d47 100644
--- a/libifupdown/interface-file.c
+++ b/libifupdown/interface-file.c
@@ -19,7 +19,6 @@
 #include "libifupdown/interface-file.h"
 #include "libifupdown/fgetline.h"
 #include "libifupdown/tokenize.h"
-#include "libifupdown/compar.h"
 
 bool
 lif_interface_file_parse(struct lif_dict *collection, const char *filename)
@@ -146,7 +145,8 @@ lif_interface_file_parse(struct lif_dict *collection, const char *filename)
 			{
 				/* Copy word1 to not mangle *token */
 				char *addon = strndup(token, word_end - token);
-				lif_dict_add_once(&cur_iface->vars, "use", addon, compar_str);
+				if (lif_dict_add_once(&cur_iface->vars, "use", addon, (lif_dict_cmp_t) strcmp) == NULL)
+					free(addon);
 
 				/* pass requires as compatibility env vars to appropriate executors (bridge, bond) */
 				if (!strcmp(addon, "dhcp"))