charon-tkm: Implement SPI generator

The get_spi callback returns a random SPI with a label encoded according
to the spi_label and spi_mask parameters read from the strongswan.conf.

src/charon-tkm/src/tkm/tkm_spi_generator.c

@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2015 Reto Buerki
+ * Copyright (C) 2015 Adrian-Ken Rueegsegger
+ * 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 <inttypes.h>
+#include <library.h>
+#include <daemon.h>
+
+#include "tkm_spi_generator.h"
+
+/**
+ * Get SPI callback arguments
+ */
+typedef struct {
+	rng_t *rng;
+	u_int64_t spi_mask;
+	u_int64_t spi_label;
+} get_spi_args_t;
+
+static get_spi_args_t *spi_args;
+
+/**
+ * Callback called to generate an IKE SPI.
+ *
+ * @param this			Callback args containing rng_t and spi mask & label
+ * @return				labeled SPI
+ */
+CALLBACK(tkm_get_spi, u_int64_t,
+	const get_spi_args_t const *this)
+{
+	u_int64_t spi;
+
+	if (!this->rng->get_bytes(this->rng, sizeof(spi), (u_int8_t*)&spi))
+	{
+		return 0;
+	}
+
+	return (spi & ~this->spi_mask) | this->spi_label;
+}
+
+bool tkm_spi_generator_register(plugin_t *plugin,
+                                plugin_feature_t *feature,
+                                bool reg, void *cb_data)
+{
+	u_int64_t spi_mask, spi_label;
+	char *spi_val;
+	rng_t *rng;
+
+	if (reg)
+	{
+		rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+		if (!rng)
+		{
+			return FALSE;
+		}
+
+		spi_val = lib->settings->get_str(lib->settings, "%s.spi_mask", NULL,
+										 lib->ns);
+		spi_mask = settings_value_as_uint64(spi_val, 0);
+
+		spi_val = lib->settings->get_str(lib->settings, "%s.spi_label", NULL,
+										 lib->ns);
+		spi_label = settings_value_as_uint64(spi_val, 0);
+
+		INIT(spi_args,
+			.rng = rng,
+			.spi_mask = spi_mask,
+			.spi_label = spi_label,
+		);
+
+		charon->ike_sa_manager->set_spi_cb(charon->ike_sa_manager,
+				tkm_get_spi, spi_args);
+		DBG1(DBG_IKE, "using SPI label 0x%.16"PRIx64" and mask 0x%.16"PRIx64,
+			 spi_label, spi_mask);
+	}
+	else
+	{
+		if (spi_args)
+		{
+			DESTROY_IF(spi_args->rng);
+			free(spi_args);
+		}
+	}
+
+	return TRUE;
+}

src/charon-tkm/src/tkm/tkm_spi_generator.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2015 Reto Buerki
+ * Copyright (C) 2015 Adrian-Ken Rueegsegger
+ * 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.
+ */
+
+/**
+ * @defgroup tkm-spi-generator spi generator
+ * @{ @ingroup tkm
+ */
+
+#ifndef TKM_SPI_GENERATOR_H_
+#define TKM_SPI_GENERATOR_H_
+
+#include <plugins/plugin.h>
+
+/**
+ * Register the TKM SPI generator callback.
+ *
+ * @return			TRUE on success
+ */
+bool tkm_spi_generator_register(plugin_t *plugin,
+                                plugin_feature_t *feature,
+                                bool reg, void *cb_data);
+
+#endif /** TKM_SPI_GENERATOR_H_ @}*/