diff --git a/shared/nm-utils/nm-shared-utils.c b/shared/nm-utils/nm-shared-utils.c
index c41b5e68c2..bd67647b10 100644
--- a/shared/nm-utils/nm-shared-utils.c
+++ b/shared/nm-utils/nm-shared-utils.c
@@ -608,6 +608,50 @@ _nm_utils_ascii_str_to_int64 (const char *str, guint base, gint64 min, gint64 ma
 	return v;
 }
 
+guint64
+_nm_utils_ascii_str_to_uint64 (const char *str, guint base, guint64 min, guint64 max, guint64 fallback)
+{
+	guint64 v;
+	const char *s = NULL;
+
+	if (str) {
+		while (g_ascii_isspace (str[0]))
+			str++;
+	}
+	if (!str || !str[0]) {
+		errno = EINVAL;
+		return fallback;
+	}
+
+	errno = 0;
+	v = g_ascii_strtoull (str, (char **) &s, base);
+
+	if (errno != 0)
+		return fallback;
+	if (s[0] != '\0') {
+		while (g_ascii_isspace (s[0]))
+			s++;
+		if (s[0] != '\0') {
+			errno = EINVAL;
+			return fallback;
+		}
+	}
+	if (v > max || v < min) {
+		errno = ERANGE;
+		return fallback;
+	}
+
+	if (   v != 0
+	    && str[0] == '-') {
+		/* I don't know why, but g_ascii_strtoull() accepts minus signs ("-2" gives 18446744073709551614).
+		 * For "-0" that is OK, but otherwise not. */
+		errno = ERANGE;
+		return fallback;
+	}
+
+	return v;
+}
+
 /*****************************************************************************/
 
 /* like nm_strcmp_p(), suitable for g_ptr_array_sort_with_data().
diff --git a/shared/nm-utils/nm-shared-utils.h b/shared/nm-utils/nm-shared-utils.h
index 7ee76799bd..bfa51def49 100644
--- a/shared/nm-utils/nm-shared-utils.h
+++ b/shared/nm-utils/nm-shared-utils.h
@@ -408,7 +408,8 @@ gboolean nm_utils_parse_inaddr_prefix (int addr_family,
                                        char **out_addr,
                                        int *out_prefix);
 
-gint64 _nm_utils_ascii_str_to_int64 (const char *str, guint base, gint64 min, gint64 max, gint64 fallback);
+gint64  _nm_utils_ascii_str_to_int64  (const char *str, guint base, gint64  min, gint64  max, gint64  fallback);
+guint64 _nm_utils_ascii_str_to_uint64 (const char *str, guint base, guint64 min, guint64 max, guint64 fallback);
 
 int _nm_utils_ascii_str_to_bool (const char *str,
                                   int default_value);