/*
 * Copyright (c) 2009 Lukas Mejdrech
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup packet
 *  @{
 */

/** @file
 *  Packet header.
 */

#ifndef __NET_PACKET_HEADER_H__
#define __NET_PACKET_HEADER_H__

#include "packet.h"

/** Returns the actual packet data length.
 *  @param[in] header The packet header.
 */
#define PACKET_DATA_LENGTH( header )		(( header )->data_end - ( header )->data_start )

/** Returns the maximum packet address length.
 *  @param[in] header The packet header.
 */
#define PACKET_MAX_ADDRESS_LENGTH( header )		(( header )->dest_addr - ( header )->src_addr )

/** Returns the minimum packet suffix.
 *  @param[in] header The packet header.
 */
#define PACKET_MIN_SUFFIX( header )		(( header )->length - ( header )->data_start - ( header )->max_content )

/** Packet integrity check magic value.
 */
#define PACKET_MAGIC_VALUE	0x11227788

/** Packet header.
 */
struct packet{
	/** Packet identifier.
	 */
	packet_id_t		packet_id;
	/** Packet queue sorting value.
	 *  The packet queue is sorted the ascending order.
	 */
	size_t			order;
	/** Packet metric.
	 */
	size_t			metric;
	/** Previous packet in the queue.
	 */
	packet_id_t		previous;
	/** Next packet in the queue.
	 */
	packet_id_t		next;
	/** Total length of the packet.
	 *  Contains the header, the addresses and the data of the packet.
	 *  Corresponds to the mapped sharable memory block.
	 */
	size_t			length;
	/** Stored source and destination addresses length.
	 */
	size_t			addr_len;
	/** Souce address offset in bytes from the beginning of the packet header.
	 */
	size_t			src_addr;
	/** Destination address offset in bytes from the beginning of the packet header.
	 */
	size_t			dest_addr;
	/** Reserved data prefix length in bytes.
	 */
	size_t			max_prefix;
	/** Reserved content length in bytes.
	 */
	size_t			max_content;
	/** Actual data start offset in bytes from the beginning of the packet header.
	 */
	size_t			data_start;
	/** Actual data end offset in bytes from the beginning of the packet header.
	 */
	size_t			data_end;
	/** Integrity check magic value.
	 */
	int				magic_value;
};

/** Returns whether the packet is valid.
 *  @param[in] packet The packet to be checked.
 *  @returns true if the packet is not NULL and the magic value is correct.
 *  @returns false otherwise.
 */
static inline int	packet_is_valid( const packet_t packet ){
	return packet && ( packet->magic_value == PACKET_MAGIC_VALUE );
}

#endif

/** @}
 */