source: mainline/uspace/lib/c/include/net/packet_header.h@ 753bca3

/*
 * 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 libc 
 *  @{
 */

/** @file
 * Packet header.
 */

#ifndef LIBC_PACKET_HEADER_H_
#define LIBC_PACKET_HEADER_H_

#include <net/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

/** @}
 */