unit-tests: Add mock nonce generator

We don't make the full nonces configurable but only the first byte,
which should be enough to force a nonce to be smaller than others.

src/libcharon/tests/Makefile.am

@@ -29,6 +29,7 @@ exchange_tests_SOURCES = \
   utils/exchange_test_helper.h utils/exchange_test_helper.c \
   utils/mock_dh.h utils/mock_dh.c \
   utils/mock_ipsec.h utils/mock_ipsec.c \
+  utils/mock_nonce_gen.h utils/mock_nonce_gen.c \
   utils/mock_sender.h utils/mock_sender.c \
   utils/sa_asserts.h \
   exchange_tests.h exchange_tests.c

src/libcharon/tests/utils/mock_nonce_gen.c

@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2016 Tobias Brunner
+ * HSR 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 "mock_nonce_gen.h"
+
+typedef struct private_nonce_gen_t private_nonce_gen_t;
+
+struct private_nonce_gen_t {
+
+	/**
+	 * Public interface
+	 */
+	nonce_gen_t public;
+
+	/**
+	 * Random number generator
+	 */
+	rng_t* rng;
+
+	/**
+	 * First byte to set to the nonces
+	 */
+	u_char first;
+};
+
+METHOD(nonce_gen_t, get_nonce, bool,
+	private_nonce_gen_t *this, size_t size, uint8_t *buffer)
+{
+	if (size > 0)
+	{
+		buffer[0] = this->first;
+		buffer++;
+		size--;
+	}
+	return this->rng->get_bytes(this->rng, size, buffer);
+}
+
+METHOD(nonce_gen_t, allocate_nonce, bool,
+	private_nonce_gen_t *this, size_t size, chunk_t *chunk)
+{
+	*chunk = chunk_alloc(size);
+	if (!get_nonce(this, chunk->len, chunk->ptr))
+	{
+		chunk_free(chunk);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(nonce_gen_t, destroy, void,
+	private_nonce_gen_t *this)
+{
+	DESTROY_IF(this->rng);
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+nonce_gen_t *mock_nonce_gen_create(u_char first)
+{
+	private_nonce_gen_t *this;
+
+	INIT(this,
+		.public = {
+			.get_nonce = _get_nonce,
+			.allocate_nonce = _allocate_nonce,
+			.destroy = _destroy,
+		},
+		.rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK),
+		.first = first,
+	);
+	if (!this->rng)
+	{
+		destroy(this);
+		return NULL;
+	}
+	return &this->public;
+}

src/libcharon/tests/utils/mock_nonce_gen.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2016 Tobias Brunner
+ * HSR 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.
+ */
+
+/**
+ * Special nonce generator that sets the first byte of the generated nonces to
+ * a fixed specified value.
+ *
+ * @defgroup mock_nonce_gen mock_nonce_gen
+ * @{ @ingroup test_utils_c
+ */
+
+#ifndef MOCK_NONCE_GEN_H_
+#define MOCK_NONCE_GEN_H_
+
+#include <crypto/nonce_gen.h>
+
+/**
+ * Creates a nonce_gen_t instance.
+ *
+ * @param first		first byte to set in generated nonces
+ * @return			created object
+ */
+nonce_gen_t *mock_nonce_gen_create(u_char first);
+
+#endif /** MOCK_NONCE_GEN_H_ @} */