diff --git a/src/s1ap/asn1c/asnGenFiles/xer_decoder.h b/src/s1ap/asn1c/asnGenFiles/xer_decoder.h
new file mode 100644
index 0000000..b951c41
--- /dev/null
+++ b/src/s1ap/asn1c/asnGenFiles/xer_decoder.h
@@ -0,0 +1,106 @@
+/*-
+ * Copyright (c) 2004-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	_XER_DECODER_H_
+#define	_XER_DECODER_H_
+
+#include <asn_application.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct asn_TYPE_descriptor_s;	/* Forward declaration */
+
+/*
+ * The XER decoder of any ASN.1 type. May be invoked by the application.
+ * Decodes CANONICAL-XER and BASIC-XER.
+ */
+asn_dec_rval_t xer_decode(
+    const struct asn_codec_ctx_s *opt_codec_ctx,
+    const struct asn_TYPE_descriptor_s *type_descriptor,
+    void **struct_ptr,  /* Pointer to a target structure's pointer */
+    const void *buffer, /* Data to be decoded */
+    size_t size         /* Size of data buffer */
+);
+
+/*
+ * Type of the type-specific XER decoder function.
+ */
+typedef asn_dec_rval_t(xer_type_decoder_f)(
+    const asn_codec_ctx_t *opt_codec_ctx,
+    const struct asn_TYPE_descriptor_s *type_descriptor, void **struct_ptr,
+    const char *opt_mname, /* Member name */
+    const void *buf_ptr, size_t size);
+
+/*******************************
+ * INTERNALLY USEFUL FUNCTIONS *
+ *******************************/
+
+/*
+ * Generalized function for decoding the primitive values.
+ * Used by more specialized functions, such as OCTET_STRING_decode_xer_utf8
+ * and others. This function should not be used by applications, as its API
+ * is subject to changes.
+ */
+asn_dec_rval_t xer_decode_general(
+    const asn_codec_ctx_t *opt_codec_ctx,
+    asn_struct_ctx_t *ctx, /* Type decoder context */
+    void *struct_key,      /* Treated as opaque pointer */
+    const char *xml_tag,   /* Expected XML tag name */
+    const void *buf_ptr, size_t size,
+    int (*opt_unexpected_tag_decoder)(void *struct_key, const void *chunk_buf,
+                                      size_t chunk_size),
+    ssize_t (*body_receiver)(void *struct_key, const void *chunk_buf,
+                             size_t chunk_size, int have_more));
+
+
+/*
+ * Fetch the next XER (XML) token from the stream.
+ * The function returns the number of bytes occupied by the chunk type,
+ * returned in the _ch_type. The _ch_type is only set (and valid) when
+ * the return value is >= 0.
+ */
+  typedef enum pxer_chunk_type {
+	PXER_WMORE,     /* Chunk type is not clear, more data expected. */
+	PXER_TAG,	    /* Complete XER tag */
+	PXER_TEXT,	    /* Plain text between XER tags */
+	PXER_COMMENT	/* A comment, may be part of */
+  } pxer_chunk_type_e;
+ssize_t xer_next_token(int *stateContext,
+	const void *buffer, size_t size, pxer_chunk_type_e *_ch_type);
+
+/*
+ * This function checks the buffer against the tag name is expected to occur.
+ */
+  typedef enum xer_check_tag {
+	XCT_BROKEN	= 0,	/* The tag is broken */
+	XCT_OPENING	= 1,	/* This is the <opening> tag */
+	XCT_CLOSING	= 2,	/* This is the </closing> tag */
+	XCT_BOTH	= 3,	/* This is the <modified/> tag */
+	XCT__UNK__MASK	= 4,	/* Mask of everything unexpected */
+	XCT_UNKNOWN_OP	= 5,	/* Unexpected <opening> tag */
+	XCT_UNKNOWN_CL	= 6,	/* Unexpected </closing> tag */
+	XCT_UNKNOWN_BO	= 7	/* Unexpected <modified/> tag */
+  } xer_check_tag_e;
+xer_check_tag_e xer_check_tag(const void *buf_ptr, int size,
+		const char *need_tag);
+
+/*
+ * Get the number of bytes consisting entirely of XER whitespace characters.
+ * RETURN VALUES:
+ * >=0:	Number of whitespace characters in the string.
+ */
+size_t xer_whitespace_span(const void *chunk_buf, size_t chunk_size);
+
+/*
+ * Skip the series of anticipated extensions.
+ */
+int xer_skip_unknown(xer_check_tag_e tcv, ber_tlv_len_t *depth);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _XER_DECODER_H_ */