iv_gen: Add IV generator that allocates IVs sequentially

1 files changed, 87 insertions, 0 deletions

diff --git a/src/libstrongswan/crypto/iv/iv_gen_seq.c b/src/libstrongswan/crypto/iv/iv_gen_seq.c
new file mode 100644
index 000000000..d8a5a2909
--- /dev/null
+++ b/src/libstrongswan/crypto/iv/iv_gen_seq.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2013 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "iv_gen_seq.h"
+
+typedef struct private_iv_gen_t private_iv_gen_t;
+
+/**
+ * Private data of an iv_gen_t object.
+ */
+struct private_iv_gen_t {
+
+	/**
+	 * Public iv_gen_t interface.
+	 */
+	iv_gen_t public;
+
+	/**
+	 * sequence number
+	 */
+	u_int64_t seq;
+};
+
+METHOD(iv_gen_t, get_iv, bool,
+	private_iv_gen_t *this, size_t size, u_int8_t *buffer)
+{
+	u_int8_t iv[sizeof(u_int64_t)];
+	size_t len = size;
+
+	if (this->seq == UINT64_MAX || len < sizeof(u_int64_t))
+	{
+		return FALSE;
+	}
+	if (len > sizeof(u_int64_t))
+	{
+		len = sizeof(u_int64_t);
+		memset(buffer, 0, size - len);
+	}
+	htoun64(iv, this->seq++);
+	memcpy(buffer + size - len, iv + sizeof(u_int64_t) - len, len);
+	return TRUE;
+}
+
+METHOD(iv_gen_t, allocate_iv, bool,
+	private_iv_gen_t *this, size_t size, chunk_t *chunk)
+{
+	*chunk = chunk_alloc(size);
+	if (!get_iv(this, chunk->len, chunk->ptr))
+	{
+		chunk_free(chunk);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(iv_gen_t, destroy, void,
+	private_iv_gen_t *this)
+{
+	free(this);
+}
+
+iv_gen_t *iv_gen_seq_create()
+{
+	private_iv_gen_t *this;
+
+	INIT(this,
+		.public = {
+			.get_iv = _get_iv,
+			.allocate_iv = _allocate_iv,
+			.destroy = _destroy,
+		},
+	);
+
+	return &this->public;
+}