1 files changed, 156 insertions, 0 deletions
diff --git a/src/libstrongswan/crypto/prf_plus.c b/src/libstrongswan/crypto/prf_plus.c
new file mode 100644
index 000000000..6bd444b1f
--- /dev/null
+++ b/src/libstrongswan/crypto/prf_plus.c
@@ -0,0 +1,156 @@
+/**
+ * @file prf_plus.c
+ * 
+ * @brief Implementation of prf_plus_t.
+ * 
+ */
+
+/*
+ * Copyright (C) 2005-2006 Martin Willi
+ * Copyright (C) 2005 Jan Hutter
+ * 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 <string.h>
+
+#include "prf_plus.h"
+
+typedef struct private_prf_plus_t private_prf_plus_t;
+
+/**
+ * Private data of an prf_plus_t object.
+ * 
+ */
+struct private_prf_plus_t {
+	/**
+	 * Public interface of prf_plus_t.
+	 */
+	prf_plus_t public;
+	
+	/**
+	 * PRF to use.
+	 */
+	prf_t *prf;
+	
+	/**
+	 * Initial seed.
+	 */
+	chunk_t seed;
+	
+	/**
+	 * Buffer to store current PRF result.
+	 */
+	chunk_t buffer;
+		
+	/**
+	 * Already given out bytes in current buffer.
+	 */
+	size_t given_out;
+	
+	/**
+	 * Octet which will be appended to the seed.
+	 */
+	u_int8_t appending_octet;
+};
+
+/**
+ * Implementation of prf_plus_t.get_bytes.
+ */
+static void get_bytes(private_prf_plus_t *this, size_t length, u_int8_t *buffer)
+{	
+	chunk_t appending_chunk;
+	size_t bytes_in_round;
+	size_t total_bytes_written = 0;
+	
+	appending_chunk.ptr = &(this->appending_octet);
+	appending_chunk.len = 1;
+	
+	while (length > 0)
+	{	/* still more to do... */
+		if (this->buffer.len == this->given_out)
+		{	/* no bytes left in buffer, get next*/	
+			this->prf->get_bytes(this->prf, this->buffer, NULL);
+			this->prf->get_bytes(this->prf, this->seed, NULL);
+			this->prf->get_bytes(this->prf, appending_chunk, this->buffer.ptr);
+			this->given_out = 0;
+			this->appending_octet++;
+		}
+		/* how many bytes can we write in this round ? */
+		bytes_in_round = min(length, this->buffer.len - this->given_out);
+		/* copy bytes from buffer with offset */
+		memcpy(buffer + total_bytes_written, this->buffer.ptr + this->given_out, bytes_in_round);
+		
+		length -= bytes_in_round;
+		this->given_out += bytes_in_round;
+		total_bytes_written += bytes_in_round;
+	}
+}
+
+/**
+ * Implementation of prf_plus_t.allocate_bytes.
+ */	
+static void allocate_bytes(private_prf_plus_t *this, size_t length, chunk_t *chunk)
+{
+	chunk->ptr = malloc(length);
+	chunk->len = length;
+	this->public.get_bytes(&(this->public), length, chunk->ptr);
+}
+
+/**
+ * Implementation of prf_plus_t.destroy.
+ */
+static void destroy(private_prf_plus_t *this)
+{
+	free(this->buffer.ptr);
+	free(this->seed.ptr);
+	free(this);
+}
+
+/*
+ * Description in header.
+ */
+prf_plus_t *prf_plus_create(prf_t *prf, chunk_t seed)
+{
+	private_prf_plus_t *this;
+	chunk_t appending_chunk;
+	
+	this = malloc_thing(private_prf_plus_t);
+
+	/* set public methods */
+	this->public.get_bytes = (void (*)(prf_plus_t *,size_t,u_int8_t*))get_bytes;
+	this->public.allocate_bytes = (void (*)(prf_plus_t *,size_t,chunk_t*))allocate_bytes;
+	this->public.destroy = (void (*)(prf_plus_t *))destroy;
+	
+	/* take over prf */
+	this->prf = prf;
+	
+	/* allocate buffer for prf output */
+	this->buffer.len = prf->get_block_size(prf);
+	this->buffer.ptr = malloc(this->buffer.len);
+
+	this->appending_octet = 0x01;
+	
+	/* clone seed */
+	this->seed.ptr = clalloc(seed.ptr, seed.len);
+	this->seed.len = seed.len;
+
+	/* do the first run */
+	appending_chunk.ptr = &(this->appending_octet);
+	appending_chunk.len = 1;
+	this->prf->get_bytes(this->prf, this->seed, NULL);
+	this->prf->get_bytes(this->prf, appending_chunk, this->buffer.ptr);
+	this->given_out = 0;
+	this->appending_octet++;
+	
+	return &(this->public);
+}