diff --git a/src/rspro/ber_tlv_length.c b/src/rspro/ber_tlv_length.c
new file mode 100644
index 0000000..b87e75e
--- /dev/null
+++ b/src/rspro/ber_tlv_length.c
@@ -0,0 +1,178 @@
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#include <asn_internal.h>
+#include <ber_tlv_length.h>
+#include <ber_tlv_tag.h>
+
+ssize_t
+ber_fetch_length(int _is_constructed, const void *bufptr, size_t size,
+		ber_tlv_len_t *len_r) {
+	const uint8_t *buf = (const uint8_t *)bufptr;
+	unsigned oct;
+
+	if(size == 0)
+		return 0;	/* Want more */
+
+	oct = *(const uint8_t *)buf;
+	if((oct & 0x80) == 0) {
+		/*
+		 * Short definite length.
+		 */
+		*len_r = oct;	/* & 0x7F */
+		return 1;
+	} else {
+		ber_tlv_len_t len;
+		size_t skipped;
+
+		if(_is_constructed && oct == 0x80) {
+			*len_r = -1;	/* Indefinite length */
+			return 1;
+		}
+
+		if(oct == 0xff) {
+			/* Reserved in standard for future use. */
+			return -1;
+		}
+
+		oct &= 0x7F;	/* Leave only the 7 LS bits */
+		for(len = 0, buf++, skipped = 1;
+			oct && (++skipped <= size); buf++, oct--) {
+
+			len = (len << 8) | *buf;
+			if(len < 0
+			|| (len >> ((8 * sizeof(len)) - 8) && oct > 1)) {
+				/*
+				 * Too large length value.
+				 */
+				return -1;
+			}
+		}
+
+		if(oct == 0) {
+			ber_tlv_len_t lenplusepsilon = (size_t)len + 1024;
+			/*
+			 * Here length may be very close or equal to 2G.
+			 * However, the arithmetics used in some decoders
+			 * may add some (small) quantities to the length,
+			 * to check the resulting value against some limits.
+			 * This may result in integer wrap-around, which
+			 * we try to avoid by checking it earlier here.
+			 */
+			if(lenplusepsilon < 0) {
+				/* Too large length value */
+				return -1;
+			}
+
+			*len_r = len;
+			return skipped;
+		}
+
+		return 0;	/* Want more */
+	}
+
+}
+
+ssize_t
+ber_skip_length(asn_codec_ctx_t *opt_codec_ctx,
+		int _is_constructed, const void *ptr, size_t size) {
+	ber_tlv_len_t vlen;	/* Length of V in TLV */
+	ssize_t tl;		/* Length of L in TLV */
+	ssize_t ll;		/* Length of L in TLV */
+	size_t skip;
+
+	/*
+	 * Make sure we didn't exceed the maximum stack size.
+	 */
+	if(_ASN_STACK_OVERFLOW_CHECK(opt_codec_ctx))
+		return -1;
+
+	/*
+	 * Determine the size of L in TLV.
+	 */
+	ll = ber_fetch_length(_is_constructed, ptr, size, &vlen);
+	if(ll <= 0) return ll;
+
+	/*
+	 * Definite length.
+	 */
+	if(vlen >= 0) {
+		skip = ll + vlen;
+		if(skip > size)
+			return 0;	/* Want more */
+		return skip;
+	}
+
+	/*
+	 * Indefinite length!
+	 */
+	ASN_DEBUG("Skipping indefinite length");
+	for(skip = ll, ptr = ((const char *)ptr) + ll, size -= ll;;) {
+		ber_tlv_tag_t tag;
+
+		/* Fetch the tag */
+		tl = ber_fetch_tag(ptr, size, &tag);
+		if(tl <= 0) return tl;
+
+		ll = ber_skip_length(opt_codec_ctx,
+			BER_TLV_CONSTRUCTED(ptr),
+			((const char *)ptr) + tl, size - tl);
+		if(ll <= 0) return ll;
+
+		skip += tl + ll;
+
+		/*
+		 * This may be the end of the indefinite length structure,
+		 * two consecutive 0 octets.
+		 * Check if it is true.
+		 */
+		if(((const uint8_t *)ptr)[0] == 0
+		&& ((const uint8_t *)ptr)[1] == 0)
+			return skip;
+
+		ptr = ((const char *)ptr) + tl + ll;
+		size -= tl + ll;
+ 	}
+
+	/* UNREACHABLE */
+}
+
+size_t
+der_tlv_length_serialize(ber_tlv_len_t len, void *bufp, size_t size) {
+	size_t required_size;	/* Size of len encoding */
+	uint8_t *buf = (uint8_t *)bufp;
+	uint8_t *end;
+	size_t i;
+
+	if(len <= 127) {
+		/* Encoded in 1 octet */
+		if(size) *buf = (uint8_t)len;
+		return 1;
+	}
+
+	/*
+	 * Compute the size of the subsequent bytes.
+	 */
+	for(required_size = 1, i = 8; i < 8 * sizeof(len); i += 8) {
+		if(len >> i)
+			required_size++;
+		else
+			break;
+	}
+
+	if(size <= required_size)
+		return required_size + 1;
+
+	*buf++ = (uint8_t)(0x80 | required_size);  /* Length of the encoding */
+
+	/*
+	 * Produce the len encoding, space permitting.
+	 */
+	end = buf + required_size;
+	for(i -= 8; buf < end; i -= 8, buf++)
+		*buf = (uint8_t)(len >> i);
+
+	return required_size + 1;
+}
+