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/*

 * 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 server implementation.

 */

#include <align.h>

#include <async.h>

#include <errno.h>

#include <futex.h>

//#include <stdio.h>

#include <unistd.h>

#include <ipc/ipc.h>

#include <sys/mman.h>

#include "../../err.h"

#include "../../messages.h"

#include "packet.h"

#include "packet_header.h"

#include "packet_server.h"

/** The default address length reserved for new packets.

 */

#define DEFAULT_ADDR_LEN    32

/** The default prefix reserved for new packets.

 */

#define DEFAULT_PREFIX      0

/** The default suffix reserved for new packets.

 */

#define DEFAULT_SUFFIX      0

/** Returns the packet identifier message parameter.

 */

#define IPC_GET_ID( call )          ( packet_id_t ) IPC_GET_ARG1( * call )

/** Returns the maximal content length message parameter.

 */

#define IPC_GET_CONTENT( call )     ( size_t ) IPC_GET_ARG1( * call )

/** Returns the maximal address length message parameter.

 */

#define IPC_GET_ADDR_LEN( call )    ( size_t ) IPC_GET_ARG2( * call )

/** Returns the maximal prefix length message parameter.

 */

#define IPC_GET_PREFIX( call )      ( size_t ) IPC_GET_ARG3( * call )

/** Returns the maximal suffix length message parameter.

 */

#define IPC_GET_SUFFIX( call )      ( size_t ) IPC_GET_ARG4( * call )

#define FREE_QUEUES_COUNT   7

/** Packet server global data.

 */

static struct{

    /** Safety lock.

     */

    futex_t lock;

    /** Free packet queues.

     */

    packet_t free[ FREE_QUEUES_COUNT ];

    /** Packet length upper bounds of the free packet queues.

     *  The maximal lengths of packets in each queue in the ascending order.

     *  The last queue is not limited.

     */

    size_t sizes[ FREE_QUEUES_COUNT ];

    /** Total packets allocated.

     */

    unsigned int count;

} ps_globals = {

    { 1 },

    { NULL, NULL, NULL, NULL, NULL, NULL, NULL },

    { PAGE_SIZE, PAGE_SIZE * 2, PAGE_SIZE * 4, PAGE_SIZE * 8, PAGE_SIZE * 16, PAGE_SIZE * 32, PAGE_SIZE * 64 },

};

/** Releases the packet and returns it to the appropriate free packet queue.

 *  Should be used only when the global data are locked.

 *  @param packet The packet to be released. Input parameter.

 */

void packet_release( packet_t packet );

/** Returns the packet of dimensions at least as given.

 *  Tries to reuse free packets first.

 *  Creates a new packet aligned to the memory page size if none available.

 *  Locks the global data during its processing.

 *  @param addr_len The source and destination addresses maximal length in bytes. Input parameter.

 *  @param max_prefix The maximal prefix length in bytes. Input parameter.

 *  @param max_content The maximal content length in bytes. Input parameter.

 *  @param max_suffix The maximal suffix length in bytes. Input parameter.

 *  @returns The packet of dimensions at least as given.

 *  @returns NULL if there is not enough memory left.

 */

packet_t packet_get( size_t addr_len, size_t max_prefix, size_t max_content, size_t max_suffix );

/** Creates a new packet of dimensions at least as given.

 *  Should be used only when the global data are locked.

 *  @param length The total length of the packet, including the header, the addresses and the data of the packet. Input parameter.

 *  @param addr_len The source and destination addresses maximal length in bytes. Input parameter.

 *  @param max_prefix The maximal prefix length in bytes. Input parameter.

 *  @param max_content The maximal content length in bytes. Input parameter.

 *  @param max_suffix The maximal suffix length in bytes. Input parameter.

 *  @returns The packet of dimensions at least as given.

 *  @returns NULL if there is not enough memory left.

 */

packet_t    packet_create( size_t length, size_t addr_len, size_t max_prefix, size_t max_content, size_t max_suffix );

/** Initializes the packet according to the given dimensions.

 *  @param packet The packet to be initialized. Input parameter.

 *  @param addr_len The source and destination addresses maximal length in bytes. Input parameter.

 *  @param max_prefix The maximal prefix length in bytes. Input parameter.

 *  @param max_content The maximal content length in bytes. Input parameter.

 *  @param max_suffix The maximal suffix length in bytes. Input parameter.

 */

void    packet_init( packet_t packet, size_t addr_len, size_t max_prefix, size_t max_content, size_t max_suffix );

/** Shares the packet memory block.

 *  @param packet The packet to be shared.

 *  @returns EOK on success.

 *  @returns EINVAL if the packet is not valid.

 *  @returns EINVAL if the calling module does not accept the memory.

 *  @returns ENOMEM if the desired and actual sizes differ.

 *  @returns Other error codes as defined for the ipc_share_in_finalize() function.

 */

int packet_reply( const packet_t packet );

int packet_server_message( ipc_callid_t callid, ipc_call_t * call, ipc_call_t * answer, int * answer_count ){

    packet_t packet;

    * answer_count = 0;

    switch( IPC_GET_METHOD( * call )){

        case IPC_M_PHONE_HUNGUP:

            return EOK;

        case NET_PACKET_CREATE_1:

            packet = packet_get( DEFAULT_ADDR_LEN, DEFAULT_PREFIX, IPC_GET_CONTENT( call ), DEFAULT_SUFFIX );

            if( ! packet ) return ENOMEM;

            * answer_count = 2;

            IPC_SET_ARG1( * answer, packet->packet_id );

            IPC_SET_ARG2( * answer, packet->length );

            return EOK;

        case NET_PACKET_CREATE_4:

            packet = packet_get( IPC_GET_ADDR_LEN( call ), IPC_GET_PREFIX( call ), IPC_GET_CONTENT( call ), IPC_GET_SUFFIX( call ));

            if( ! packet ) return ENOMEM;

            * answer_count = 2;

            IPC_SET_ARG1( * answer, packet->packet_id );

            IPC_SET_ARG2( * answer, packet->length );

            return EOK;

        case NET_PACKET_GET:

            packet = pm_find( IPC_GET_ID( call ));

            if( ! packet_is_valid( packet )) return ENOENT;

            return packet_reply( packet );

        case NET_PACKET_GET_SIZE:

            packet = pm_find( IPC_GET_ID( call ));

            if( ! packet_is_valid( packet )) return ENOENT;

            * answer_count = 1;

            IPC_SET_ARG1( * answer, packet->length );

            return EOK;

        case NET_PACKET_RELEASE:

            packet = pm_find( IPC_GET_ID( call ));

            if( ! packet_is_valid( packet )) return ENOENT;

            futex_down( & ps_globals.lock );

            pq_destroy( packet, packet_release );

            futex_up( & ps_globals.lock );

            return EOK;

    }

    return ENOTSUP;

}

void packet_release( packet_t packet ){

    int index;

    for( index = 0; ( index < FREE_QUEUES_COUNT - 1 ) && ( packet->length > ps_globals.sizes[ index ] ); ++ index );

    ps_globals.free[ index ] = pq_add( ps_globals.free[ index ], packet, packet->length, packet->length );

}

packet_t packet_get( size_t addr_len, size_t max_prefix, size_t max_content, size_t max_suffix ){

    int index;

    packet_t packet;

    size_t length;

    length = ALIGN_UP( sizeof( struct packet ) + 2 * addr_len + max_prefix + max_content + max_suffix, PAGE_SIZE );

    futex_down( & ps_globals.lock );

    for( index = 0; index < FREE_QUEUES_COUNT - 1; ++ index ){

        if( length <= ps_globals.sizes[ index ] ){

            packet = ps_globals.free[ index ];

            while( packet_is_valid( packet ) && ( packet->length < length )){

                packet = pm_find( packet->next );

            }

            if( packet ){

                packet_init( packet, addr_len, max_prefix, max_content, max_suffix );

                futex_up( & ps_globals.lock );

                return packet;

            }

        }

    }

    packet = packet_create( length, addr_len, max_prefix, max_content, max_suffix );

    futex_up( & ps_globals.lock );

    return packet;

}

packet_t packet_create( size_t length, size_t addr_len, size_t max_prefix, size_t max_content, size_t max_suffix ){

    ERROR_DECLARE;

    packet_t    packet;

    // already locked

    packet = ( packet_t ) mmap( NULL, length, PROTO_READ | PROTO_WRITE, MAP_SHARED | MAP_ANONYMOUS, 0, 0 );

    if( packet == MAP_FAILED ) return NULL;

    ++ ps_globals.count;

    packet->packet_id = ps_globals.count;

    packet->length = length;

    packet_init( packet, addr_len, max_prefix, max_content, max_suffix );

    packet->magic_value = PACKET_MAGIC_VALUE;

    if( ERROR_OCCURRED( pm_add( packet ))){

        munmap( packet, packet->length );

        return NULL;

    }

    packet_release( packet );

    return packet;

}

void packet_init( packet_t packet, size_t addr_len, size_t max_prefix, size_t max_content, size_t max_suffix ){

    packet->order = 0;

    packet->metric = 0;

    packet->previous = 0;

    packet->next = 0;

    packet->addr_len = addr_len;

    packet->src_addr = sizeof( struct packet );

    packet->dest_addr = packet->src_addr + packet->addr_len;

    packet->max_prefix = max_prefix;

    packet->max_content = max_content;

    packet->data_start = packet->dest_addr + packet->addr_len + packet->max_prefix;

    packet->data_end = packet->data_start;

}

int packet_reply( const packet_t packet ){

    ipc_callid_t    callid;

    size_t          size;

    if( ! packet_is_valid( packet )) return EINVAL;

    if( ipc_share_in_receive( & callid, & size ) <= 0 ) return EINVAL;

    if( size != packet->length ) return ENOMEM;

    return ipc_share_in_finalize( callid, packet, PROTO_READ | PROTO_WRITE );

}

/** @}

 */