1 files changed, 136 insertions, 0 deletions
diff --git a/src/libstrongswan/plugins/padlock/padlock_rng.c b/src/libstrongswan/plugins/padlock/padlock_rng.c
new file mode 100644
index 000000000..50d9f0c43
--- /dev/null
+++ b/src/libstrongswan/plugins/padlock/padlock_rng.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2008 Martin Willi
+ * 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.
+ *
+ * $Id$
+ */
+
+#include "padlock_rng.h"
+
+typedef struct private_padlock_rng_t private_padlock_rng_t;
+typedef enum padlock_quality_factor_t padlock_quality_factor_t;
+
+/**
+ * Padlock RNG quality factors
+ */
+enum padlock_quality_factor_t {
+	/* Lowest quality: Reads 8 bytes */
+	PADLOCK_QF0 = 0x00,
+	/* Medium quality: Reads 4 bytes */
+	PADLOCK_QF1 = 0x01,
+	/* Better quality: Reads 2 bytes */
+	PADLOCK_QF2 = 0x10,
+	/* Highest quality: Reads 1 byte */
+	PADLOCK_QF3 = 0x11,
+};
+
+/**
+ * Private data of an padlock_rng_t object.
+ */
+struct private_padlock_rng_t {
+	
+	/**
+	 * Public padlock_rng_t interface.
+	 */
+	padlock_rng_t public;
+	
+	/**
+	 * Padlock quality factor
+	 */
+	padlock_quality_factor_t quality;
+};
+
+/**
+ * Get bytes from Padlock RNG. buf should have space for (len + 7)
+ */
+static void rng(char *buf, int len, int quality)
+{
+	while (len > 0)
+	{
+		int status;
+		
+		/* run XSTORE until we have all bytes needed. We do not use REP, as
+		 * this should not be performance critical and it's easier this way. */
+		asm volatile (
+			".byte 0x0F,0xA7,0xC0 \n\t"
+			: "=D"(buf), "=a"(status)
+			: "d"(quality), "D"(buf));
+		
+		/* bits[0..4] of status word contains the number of bytes read */
+		len -= status & 0x1F;
+	}
+}
+
+/**
+ * Implementation of padlock_rng_t.allocate_bytes.
+ */
+static void allocate_bytes(private_padlock_rng_t *this, size_t bytes,
+						   chunk_t *chunk)
+{
+	chunk->len = bytes;
+	/* padlock requires some additional bytes */
+	chunk->ptr = malloc(bytes + 7);
+	
+	rng(chunk->ptr, chunk->len, this->quality);
+}
+
+/**
+ * Implementation of padlock_rng_t.get_bytes.
+ */
+static void get_bytes(private_padlock_rng_t *this, size_t bytes,
+					  u_int8_t *buffer)
+{
+	chunk_t chunk;
+	
+	/* Padlock needs a larger buffer than "bytes", we need a new buffer */
+	allocate_bytes(this, bytes, &chunk);
+	memcpy(buffer, chunk.ptr, bytes);
+	chunk_clear(&chunk);
+}
+
+/**
+ * Implementation of padlock_rng_t.destroy.
+ */
+static void destroy(private_padlock_rng_t *this)
+{
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+padlock_rng_t *padlock_rng_create(rng_quality_t quality)
+{
+	private_padlock_rng_t *this = malloc_thing(private_padlock_rng_t);
+	
+	this->public.rng.get_bytes = (void (*) (rng_t *, size_t, u_int8_t*)) get_bytes;
+	this->public.rng.allocate_bytes = (void (*) (rng_t *, size_t, chunk_t*)) allocate_bytes;
+	this->public.rng.destroy = (void (*) (rng_t *))destroy;
+	
+	/* map RNG quality to Padlock quality factor */
+	switch (quality)
+	{
+		case RNG_WEAK:
+			this->quality = PADLOCK_QF0;
+			break;
+		case RNG_STRONG:
+			this->quality = PADLOCK_QF1;
+			break;
+		case RNG_REAL:
+			this->quality = PADLOCK_QF3;
+			break;
+	}
+	
+	return &this->public;
+}
+