1 files changed, 159 insertions, 0 deletions
diff --git a/skeletons/ber_tlv_length.c b/skeletons/ber_tlv_length.c
new file mode 100644
index 00000000..cd08f6ab
--- /dev/null
+++ b/skeletons/ber_tlv_length.c
@@ -0,0 +1,159 @@
+/*-
+ * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#include <constr_TYPE.h>
+#include <ber_tlv_length.h>
+#include <ber_tlv_tag.h>
+
+ssize_t
+ber_fetch_length(int _is_constructed, void *bufptr, size_t size,
+		ber_tlv_len_t *len_r) {
+	uint8_t *buf = bufptr;
+	unsigned oct;
+
+	if(size == 0)
+		return 0;	/* Want more */
+
+	oct = *(uint8_t *)buf;
+	if((oct & 0x80) == 0) {
+		/*
+		 * Short definite length.
+		 */
+		*len_r = (oct & 0x7F);
+		return 1;
+	} else {
+		ber_tlv_len_t len;
+		ssize_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) {
+			*len_r = len;
+			return skipped;
+		}
+
+		return 0;	/* Want more */
+	}
+
+}
+
+ssize_t
+ber_skip_length(int _is_constructed, 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 */
+	ssize_t skip;
+
+	/*
+	 * 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 += 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(BER_TLV_CONSTRUCTED(ptr),
+			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(((uint8_t *)ptr)[0] == 0
+		&& ((uint8_t *)ptr)[1] == 0)
+			return skip;
+
+		ptr  += tl + ll;
+		size -= tl + ll;
+ 	}
+
+	/* UNREACHABLE */
+}
+
+ssize_t
+der_tlv_length_serialize(ber_tlv_len_t len, void *bufp, size_t size) {
+	ssize_t computed_size;	/* Size of len encoding */
+	uint8_t *buf = bufp;
+	uint8_t *end;
+	int i;
+
+	if(len <= 127) {
+		/* Encoded in 1 octet */
+		if(size) *buf = len;
+		return 1;
+	}
+
+	/*
+	 * Compute the size of the subsequent bytes.
+	 */
+	computed_size = sizeof(len);	/* assert(sizeof(len)<128), n.p. */
+	for(i = (8*(sizeof(len)-1)); i > 0; i -= 8) {
+		if((len >> i) & 0xFF) break;
+		computed_size--;
+	}
+
+	if(size) {
+		*buf++ = 0x80 | computed_size;	/* Length of the encoding */
+		size--;
+	}
+
+	/*
+	 * Produce the len encoding, space permitting.
+	 */
+	if(size > computed_size)
+		end = buf + computed_size;
+	else
+		end = buf + size;
+	for((void)i /* Reuse bits count */; buf < end; i -= 8, buf++) {
+		*buf = (len >> i) & 0xFF;
+	}
+
+	return computed_size + 1;
+}
+