1 files changed, 102 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..98d0c15a6
--- /dev/null
+++ b/src/libstrongswan/crypto/iv/iv_gen_seq.c
@@ -0,0 +1,102 @@
+/*
+ * 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;
+
+	/**
+	 * Salt to mask counter
+	 */
+	u_int8_t *salt;
+};
+
+METHOD(iv_gen_t, get_iv, bool,
+	private_iv_gen_t *this, u_int64_t seq, size_t size, u_int8_t *buffer)
+{
+	u_int8_t iv[sizeof(u_int64_t)];
+	size_t len = size;
+
+	if (!this->salt)
+	{
+		return FALSE;
+	}
+	if (len > sizeof(u_int64_t))
+	{
+		len = sizeof(u_int64_t);
+		memset(buffer, 0, size - len);
+	}
+	htoun64(iv, seq);
+	memxor(iv, this->salt, sizeof(u_int64_t));
+	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, u_int64_t seq, size_t size, chunk_t *chunk)
+{
+	*chunk = chunk_alloc(size);
+	if (!get_iv(this, seq, chunk->len, chunk->ptr))
+	{
+		chunk_free(chunk);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(iv_gen_t, destroy, void,
+	private_iv_gen_t *this)
+{
+	free(this->salt);
+	free(this);
+}
+
+iv_gen_t *iv_gen_seq_create()
+{
+	private_iv_gen_t *this;
+	rng_t *rng;
+
+	INIT(this,
+		.public = {
+			.get_iv = _get_iv,
+			.allocate_iv = _allocate_iv,
+			.destroy = _destroy,
+		},
+	);
+
+	rng = lib->crypto->create_rng(lib->crypto, RNG_STRONG);
+	if (rng)
+	{
+		this->salt = malloc(sizeof(u_int64_t));
+		if (!rng->get_bytes(rng, sizeof(u_int64_t), this->salt))
+		{
+			free(this->salt);
+			this->salt = NULL;
+		}
+		rng->destroy(rng);
+	}
+
+	return &this->public;
+}