diff --git a/include/osmocom/rspro/per_decoder.h b/include/osmocom/rspro/per_decoder.h
new file mode 100644
index 0000000..5541bae
--- /dev/null
+++ b/include/osmocom/rspro/per_decoder.h
@@ -0,0 +1,78 @@
+/*-
+ * Copyright (c) 2005, 2007 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	_PER_DECODER_H_
+#define	_PER_DECODER_H_
+
+#include <asn_application.h>
+#include <per_support.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct asn_TYPE_descriptor_s;	/* Forward declaration */
+
+/*
+ * Unaligned PER decoder of a "complete encoding" as per X.691#10.1.
+ * On success, this call always returns (.consumed >= 1), as per X.691#10.1.3.
+ */
+asn_dec_rval_t uper_decode_complete(struct asn_codec_ctx_s *opt_codec_ctx,
+	struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+	void **struct_ptr,	/* Pointer to a target structure's pointer */
+	const void *buffer,	/* Data to be decoded */
+	size_t size		/* Size of data buffer */
+	);
+
+/*
+ * Unaligned PER decoder of any ASN.1 type. May be invoked by the application.
+ * WARNING: This call returns the number of BITS read from the stream. Beware.
+ */
+asn_dec_rval_t uper_decode(struct asn_codec_ctx_s *opt_codec_ctx,
+	struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+	void **struct_ptr,	/* Pointer to a target structure's pointer */
+	const void *buffer,	/* Data to be decoded */
+	size_t size,		/* Size of data buffer */
+	int skip_bits,		/* Number of unused leading bits, 0..7 */
+	int unused_bits		/* Number of unused tailing bits, 0..7 */
+	);
+
+/*
+ * Aligned PER decoder of a "complete encoding" as per X.691#10.1.
+ * On success, this call always returns (.consumed >= 1), as per X.691#10.1.3.
+ */
+asn_dec_rval_t aper_decode_complete(struct asn_codec_ctx_s *opt_codec_ctx,
+									struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+									void **struct_ptr,	/* Pointer to a target structure's pointer */
+									const void *buffer,	/* Data to be decoded */
+									size_t size		/* Size of data buffer */
+									);
+
+/*
+ * Aligned PER decoder of any ASN.1 type. May be invoked by the application.
+ * WARNING: This call returns the number of BITS read from the stream. Beware.
+ */
+asn_dec_rval_t aper_decode(struct asn_codec_ctx_s *opt_codec_ctx,
+						   struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+						   void **struct_ptr,	/* Pointer to a target structure's pointer */
+						   const void *buffer,	/* Data to be decoded */
+						   size_t size,		/* Size of data buffer */
+						   int skip_bits,		/* Number of unused leading bits, 0..7 */
+						   int unused_bits		/* Number of unused tailing bits, 0..7 */
+					       );
+/*
+ * Type of the type-specific PER decoder function.
+ */
+typedef asn_dec_rval_t (per_type_decoder_f)(asn_codec_ctx_t *opt_codec_ctx,
+		struct asn_TYPE_descriptor_s *type_descriptor,
+		asn_per_constraints_t *constraints,
+		void **struct_ptr,
+		asn_per_data_t *per_data
+	);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _PER_DECODER_H_ */