diff --git a/skeletons/asn_internal.h b/skeletons/asn_internal.h
new file mode 100644
index 0000000..6a44cab
--- /dev/null
+++ b/skeletons/asn_internal.h
@@ -0,0 +1,72 @@
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+/*
+ * Declarations internally useful for the ASN.1 support code.
+ */
+#ifndef	_ASN_INTERNAL_H_
+#define	_ASN_INTERNAL_H_
+
+#define	ASN1C_ENVIRONMENT_VERSION	96	/* Compile-time version */
+int get_asn1c_environment_version(void);	/* Run-time version */
+
+#include <asn_types.h>
+#include <constr_TYPE.h>
+
+#define	CALLOC(nmemb, size)	calloc(nmemb, size)
+#define	MALLOC(size)		malloc(size)
+#define	REALLOC(oldptr, size)	realloc(oldptr, size)
+#define	FREEMEM(ptr)		free(ptr)
+
+/*
+ * A macro for debugging the ASN.1 internals.
+ * You may enable or override it.
+ */
+#ifndef	ASN_DEBUG	/* If debugging code is not defined elsewhere... */
+#if	EMIT_ASN_DEBUG == 1	/* And it was asked to emit this code... */
+#ifdef	__GNUC__
+#define	ASN_DEBUG(fmt, args...)	do {		\
+		fprintf(stderr, fmt, ##args);	\
+		fprintf(stderr, "\n");		\
+	} while(0)
+#else	/* !__GNUC__ */
+extern void ASN_DEBUG_f(const char *fmt, ...);
+#define	ASN_DEBUG	ASN_DEBUG_f
+#endif	/* __GNUC__ */
+#else	/* EMIT_ASN_DEBUG != 1 */
+#ifdef	__GNUC__
+#define	ASN_DEBUG(fmt, args...)	((void)0)	/* Emit a no-op operator */
+#else	/* __GNUC__ */
+static void ASN_DEBUG(const char *fmt, ...) { (void)fmt; };
+#endif	/* __GNUC__ */
+#endif	/* EMIT_ASN_DEBUG */
+#endif	/* ASN_DEBUG */
+
+/*
+ * Invoke the application-supplied callback and fail, if something is wrong.
+ */
+#define	__ASN_E_cbc(buf, size)	(cb((buf), (size), app_key) == -1)
+#define	_ASN_E_CALLBACK(foo)	do {					\
+		if(foo)	_ASN_ENCODE_FAILED;				\
+	} while(0)
+#define	_ASN_CALLBACK(buf, size)					\
+	_ASN_E_CALLBACK(__ASN_E_cbc(buf, size))
+#define	_ASN_CALLBACK2(buf1, size1, buf2, size2)			\
+	_ASN_E_CALLBACK(__ASN_E_cbc(buf1, size1) || __ASN_E_cbc(buf2, size2))
+#define	_ASN_CALLBACK3(buf1, size1, buf2, size2, buf3, size3)		\
+	_ASN_E_CALLBACK(__ASN_E_cbc(buf1, size1)			\
+		|| __ASN_E_cbc(buf2, size2)				\
+		|| __ASN_E_cbc(buf3, size3))
+
+#define	_i_ASN_TEXT_INDENT(nl, level) do {				\
+		int __level = (level);					\
+		int __nl = ((nl) != 0);					\
+		int __i;						\
+		if(__nl) _ASN_CALLBACK("\n", 1);			\
+		for(__i = 0; __i < __level; __i++)			\
+			_ASN_CALLBACK("    ", 4);			\
+		er.encoded += __nl + 4 * __level;			\
+} while(0)
+
+#endif	/* _ASN_INTERNAL_H_ */