source: mainline/uspace/lib/socket/include/packet/packet_header.h@ 849ed54

/*
 * 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/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

/** @}
 */