Subversion Repositories HelenOS

/*

 * Copyright (c) 2008 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 udp

 *  @{

 */

/** @file

 *  UDP module implementation.

 *  @see udp.h

 */

#include <async.h>

#include <fibril_sync.h>

#include <malloc.h>

#include <ipc/ipc.h>

#include <ipc/services.h>

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

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

#include "../../modules.h"

#include "../../structures/dynamic_fifo.h"

#include "../../structures/packet/packet_client.h"

#include "../../include/in.h"

#include "../../include/inet.h"

#include "../../include/ip_client.h"

#include "../../include/ip_interface.h"

#include "../../include/ip_protocols.h"

#include "../../include/icmp_client.h"

#include "../../include/icmp_interface.h"

#include "../../include/socket.h"

#include "../../include/socket_errno.h"

#include "../../socket/socket_core.h"

#include "../../socket/socket_messages.h"

#include "../tl_messages.h"

#include "udp.h"

#include "udp_header.h"

#include "udp_module.h"

/** Maximum UDP fragment size.

 */

#define MAX_UDP_FRAGMENT_SIZE   65535

/** Free ports pool start.

 */

#define UDP_FREE_PORTS_START    1025

/** Free ports pool end.

 */

#define UDP_FREE_PORTS_END      65535

/** Processes the received UDP packet queue.

 *  Is used as an entry point from the underlying IP module.

 *  Notifies the destination socket application.

 *  Releases the packet on error or send an ICMP error notification..

 *  @param device_id The device identifier. Ignored parameter.

 *  @param packet The received packet queue. Input/output parameter.

 *  @param receiver The target service. Ignored parameter.

 *  @param error The packet error reporting service. Prefixes the received packet. Input parameter.

 *  @returns EOK on success.

 *  @returns EINVAL if the packet is not valid.

 *  @returns EINVAL if the stored packet address is not the an_addr_t.

 *  @returns EINVAL if the packet does not contain any data.

 *  @returns NO_DATA if the packet content is shorter than the user datagram header.

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

 *  @returns EADDRNOTAVAIL if the destination socket does not exist.

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

 */

int udp_received_msg( device_id_t device_id, packet_t packet, services_t receiver, services_t error );

/** Releases the packet and returns the result.

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

 *  @param result The result to be returned. Input parameter.

 *  @return The result parameter.

 */

static int  release_and_return( packet_t packet, int result );

/** Sends the port unreachable ICMP notification.

 *  Sends the first packet and releases all the others.

 *  Releases the packet queu on error.

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

 *  @param error The packet error reporting service. Prefixes the received packet. Input parameter.

 */

void    udp_send_icmp_port_unreachable( packet_t packet, services_t error );

/** @name Socket messages processing functions

 */

/*@{*/

/** Processes the socket client messages.

 *  Runs until the client module disconnects.

 *  @param callid The message identifier. Input parameter.

 *  @param call The message parameters. Input parameter.

 *  @returns EOK on success.

 *  @see socket.h

 */

int process_client_messages( ipc_callid_t callid, ipc_call_t call );

/** Sends data from the socket to the remote address.

 *  Binds the socket to a free port if not already connected/bound.

 *  Handles the NET_SOCKET_SENDTO message.

 *  @param local_sockets The application local sockets. Input/output parameter.

 *  @param socket_id Socket identifier. Input parameter.

 *  @param addr The destination address. Input parameter.

 *  @param addrlen The address length. Input parameter.

 *  @param fragments The number of data fragments. Input parameter.

 *  @param flags Various send flags. Input parameter.

 *  @returns EOK on success.

 *  @returns EAFNOTSUPPORT if the address family is not supported.

 *  @returns ENOTSOCK if the socket is not found.

 *  @returns EINVAL if the address is invalid.

 *  @returns ENOTCONN if the sending socket is not and cannot be bound.

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

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

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

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

 */

int udp_sendto_message( socket_cores_ref local_sockets, int socket_id, void * addr, size_t addrlen, int fragments, int flags );

/** Receives data to the socket.

 *  Handles the NET_SOCKET_RECVFROM message.

 *  @param local_sockets The application local sockets. Input parameter.

 *  @param socket_id Socket identifier. Input parameter.

 *  @param flags Various receive flags. Input parameter.

 *  @returns The number of bytes received.

 *  @returns ENOTSOCK if the socket is not found.

 *  @returns NO_DATA if there are no received packets or data.

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

 *  @returns EINVAL if the received address is not an IP address.

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

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

 */

int udp_recvfrom_message( socket_cores_ref local_sockets, int socket_id, int flags );

/*@}*/

/** Receives data from the socket.

 *  The received data buffer is allocated and returned.

 *  @param data The data buffer to be filled. Output parameter.

 *  @param length The buffer length. Output parameter.

 *  @returns EOK on success.

 *  @returns EBADMEM if the data or the length parameter is NULL.

 *  @returns EINVAL if the client does not send data.

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

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

 */

int socket_read_data( void ** data, size_t * length );

/** Receives data from the socket into a packet.

 *  @param packet The new created packet. Output parameter.

 *  @param prefix Reserved packet data prefix length. Input parameter.

 *  @param address_in The destination address to be set. Input parameter.

 *  @returns Number of bytes received.

 *  @returns EINVAL if the client does not send data.

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

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

 */

int socket_read_packet_data( packet_ref packet, size_t prefix, struct sockaddr_in * address_in );

/** Replies the data to the socket.

 *  @param data The data buffer to be sent. Input parameter.

 *  @param data_length The buffer length. Input parameter.

 *  @returns EOK on success.

 *  @returns EINVAL if the client does not expect all the data.

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

 */

int socket_write_data( void * data, size_t data_length );

/** UDP global data.

 */

udp_globals_t   udp_globals;

int udp_initialize( async_client_conn_t client_connection ){

    ERROR_DECLARE;

    fibril_rwlock_initialize( & udp_globals.lock );

    fibril_rwlock_write_lock( & udp_globals.lock );

    udp_globals.icmp_phone = icmp_connect_module( SERVICE_ICMP );

    if( udp_globals.icmp_phone < 0 ){

        return udp_globals.icmp_phone;

    }

    udp_globals.ip_phone = ip_bind_service( SERVICE_IP, IPPROTO_UDP, SERVICE_UDP, client_connection, udp_received_msg );

    if( udp_globals.ip_phone < 0 ){

        return udp_globals.ip_phone;

    }

    ERROR_PROPAGATE( ip_packet_size_req( udp_globals.ip_phone, -1, & udp_globals.addr_len, & udp_globals.prefix, & udp_globals.content, & udp_globals.suffix ));

    ERROR_PROPAGATE( socket_ports_initialize( & udp_globals.sockets ));

    udp_globals.prefix += sizeof( udp_header_t );

    udp_globals.content -= sizeof( udp_header_t );

    udp_globals.last_used_port = UDP_FREE_PORTS_START - 1;

    fibril_rwlock_write_unlock( & udp_globals.lock );

    return EOK;

}

int udp_received_msg( device_id_t device_id, packet_t packet, services_t receiver, services_t error ){

    ERROR_DECLARE;

    int             length;

    int             offset;

    uint8_t *       data;

    udp_header_ref  header;

    socket_core_ref *   socket;

    packet_t        next_packet;

    int             total_length;

//  uint16_t        checksum;

    int             fragments;

    packet_t        tmp_packet;

    icmp_type_t     type;

    icmp_code_t     code;

    if( error ){

        switch( error ){

            case SERVICE_ICMP:

                // process error

                // TODO remove debug dump

                // length = icmp_client_header_length( packet );

                length = icmp_client_process_packet( packet, & type, & code, NULL, NULL );

                if( length < 0 ){

                    return release_and_return( packet, length );

                }

                printf( "ICMP error %d (%d) in packet %d\n", type, code, packet_get_id( packet ) );

                if( ERROR_OCCURRED( packet_trim( packet, length, 0 ))){

                    return release_and_return( packet, ERROR_CODE );

                }

                break;

            default:

                return release_and_return( packet, ENOTSUP );

        }

    }

    // TODO process received ipopts?

    offset = ip_client_process_packet( packet, NULL, NULL, NULL, NULL, NULL );

    if( offset < 0 ){

        return release_and_return( packet, offset );

    }

    length = packet_get_data_length( packet );

    if( length <= 0 ){

        return release_and_return( packet, EINVAL );

    }

    if( length < sizeof( udp_header_t ) + offset ){

        return release_and_return( packet, NO_DATA );

    }

    data = packet_get_data( packet );

    if( ! data ){

        return release_and_return( packet, NO_DATA );

    }

    // get udp header

    header = ( udp_header_ref )( data + offset );

    // find the destination socket

    socket = socket_ports_find( & udp_globals.sockets, ntohs( header->dest ));

    if( ! socket ){

        udp_send_icmp_port_unreachable( packet, error );

        return EADDRNOTAVAIL;

    }

    // trim after successful processing to be able to send an ICMP error message!

    ERROR_PROPAGATE( packet_trim( packet, offset, 0 ));

    // count the received packet fragments

    next_packet = packet;

    fragments = 0;

    total_length = ntohs( header->len );

    do{

        ++ fragments;

        length = packet_get_data_length( packet );

        if( ! length ){

            return release_and_return( packet, NO_DATA );

        }

        if( total_length < length ){

            // cut of the suffix if too long

            if( ERROR_OCCURRED( packet_trim( next_packet, 0, length - total_length ))){

                return release_and_return( packet, ERROR_CODE );

            }

            // relese the rest of the packet fragments

            tmp_packet = pq_next( next_packet );

            while( tmp_packet ){

                next_packet = pq_detach( tmp_packet );

                pq_release( udp_globals.net_phone, packet_get_id( tmp_packet ));

                tmp_packet = next_packet;

            }

            break;

        }

        total_length -= length;

    /*  if( header->header_checksum ){

        }

    */

    }while(( next_packet = pq_next( next_packet )) && ( total_length > 0 ));

    // queue the received packet

    if( ERROR_OCCURRED( dyn_fifo_push( &( ** socket ).received, packet_get_id( packet ), SOCKET_MAX_RECEIVED_SIZE ))){

        return release_and_return( packet, ERROR_CODE );

    }

    // notify the destination socket

    async_msg_2(( ** socket ).phone, NET_SOCKET_RECEIVED, ( ** socket ).socket_id, fragments );

    return EOK;

}

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

    ERROR_DECLARE;

    packet_t    packet;

    * answer_count = 0;

    switch( IPC_GET_METHOD( * call )){

        case NET_TL_RECEIVED:

            fibril_rwlock_read_lock( & udp_globals.lock );

            if( ! ERROR_OCCURRED( packet_translate( udp_globals.net_phone, & packet, IPC_GET_PACKET( call )))){

                ERROR_CODE = udp_received_msg( IPC_GET_DEVICE( call ), packet, SERVICE_UDP, IPC_GET_ERROR( call ));

            }

            fibril_rwlock_read_unlock( & udp_globals.lock );

            return ERROR_CODE;

        case IPC_M_CONNECT_TO_ME:

            return process_client_messages( callid, * call );

    }

    return ENOTSUP;

}

int process_client_messages( ipc_callid_t callid, ipc_call_t call ){

    ERROR_DECLARE;

    int                     res;

    bool                    keep_on_going = true;

    socket_cores_t          local_sockets;

    int                     app_phone = IPC_GET_PHONE( & call );

    void *                  addr;

    size_t                  addrlen;

    fibril_rwlock_t         lock;

    ipc_call_t              answer;

    int                     answer_count;

    /*

     * Accept the connection

     *  - Answer the first IPC_M_CONNECT_ME_TO call.

     */

    ipc_answer_0( callid, EOK );

    socket_cores_initialize( & local_sockets );

    fibril_rwlock_initialize( & lock );

    while( keep_on_going ){

        // refresh data

        answer_count = 0;

        IPC_SET_RETVAL( answer, 0 );

        // just to be precize

        IPC_SET_METHOD( answer, 0 );

        IPC_SET_ARG1( answer, 0 );

        IPC_SET_ARG2( answer, 0 );

        IPC_SET_ARG3( answer, 0 );

        IPC_SET_ARG4( answer, 0 );

        IPC_SET_ARG5( answer, 0 );

        callid = async_get_call( & call );

//      printf( "message %d\n", IPC_GET_METHOD( * call ));

        switch( IPC_GET_METHOD( call )){

            case IPC_M_PHONE_HUNGUP:

                keep_on_going = false;

                res = EOK;

                break;

            case NET_SOCKET:

                fibril_rwlock_write_lock( & lock );

                res = socket_create( & local_sockets, app_phone, SOCKET_SET_SOCKET_ID( answer ));

                fibril_rwlock_write_unlock( & lock );

                * SOCKET_SET_HEADER_SIZE( answer ) = sizeof( udp_header_t );

                * SOCKET_SET_DATA_FRAGMENT_SIZE( answer ) = MAX_UDP_FRAGMENT_SIZE;

                answer_count = 3;

                break;

            case NET_SOCKET_BIND:

                if( ERROR_OCCURRED( socket_read_data( & addr, & addrlen ))){

                    res = ERROR_CODE;

                    break;

                }

                fibril_rwlock_write_lock( & lock );

                fibril_rwlock_write_lock( & udp_globals.lock );

                res = socket_bind( & local_sockets, & udp_globals.sockets, SOCKET_GET_SOCKET_ID( call ), addr, addrlen, UDP_FREE_PORTS_START, UDP_FREE_PORTS_END, udp_globals.last_used_port );

                fibril_rwlock_write_unlock( & udp_globals.lock );

                fibril_rwlock_write_unlock( & lock );

                free( addr );

                break; 

            case NET_SOCKET_SENDTO:

                if( ERROR_OCCURRED( socket_read_data( & addr, & addrlen ))){

                    res = ERROR_CODE;

                    break;

                }

                fibril_rwlock_read_lock( & lock );

                fibril_rwlock_read_lock( & udp_globals.lock );

                res = udp_sendto_message( & local_sockets, SOCKET_GET_SOCKET_ID( call ), addr, addrlen, SOCKET_GET_DATA_FRAGMENTS( call ), SOCKET_GET_FLAGS( call ));

                fibril_rwlock_read_unlock( & udp_globals.lock );

                fibril_rwlock_read_unlock( & lock );

                free( addr );

                break;

            case NET_SOCKET_RECVFROM:

                fibril_rwlock_read_lock( & lock );

                fibril_rwlock_read_lock( & udp_globals.lock );

                res = udp_recvfrom_message( & local_sockets, SOCKET_GET_SOCKET_ID( call ), SOCKET_GET_FLAGS( call ));

                fibril_rwlock_read_unlock( & udp_globals.lock );

                fibril_rwlock_read_unlock( & lock );

                if( res > 0 ){

                    * SOCKET_SET_READ_DATA_LENGTH( answer ) = res;

                    * SOCKET_SET_ADDRESS_LENGTH( answer ) = sizeof( struct sockaddr_in );

                    answer_count = 2;

                    res = EOK;

                }

                break;

            case NET_SOCKET_CLOSE:

                fibril_rwlock_write_lock( & lock );

                fibril_rwlock_write_lock( & udp_globals.lock );

                res = socket_destroy( udp_globals.net_phone, SOCKET_GET_SOCKET_ID( call ), & local_sockets, & udp_globals.sockets );

                fibril_rwlock_write_unlock( & udp_globals.lock );

                fibril_rwlock_write_unlock( & lock );

                break;

            case NET_SOCKET_GETSOCKOPT:

            case NET_SOCKET_SETSOCKOPT:

            default:

                res = ENOTSUP;

                break;

        }

//      printf( "res = %d\n", res );

        switch( answer_count ){

            case 0:     ipc_answer_0( callid, res );

                    continue;

            case 1:     ipc_answer_1( callid, res, IPC_GET_ARG1( answer ));

                    continue;

            case 2:     ipc_answer_2( callid, res, IPC_GET_ARG1( answer ), IPC_GET_ARG2( answer ));

                    continue;

            case 3:     ipc_answer_3( callid, res, IPC_GET_ARG1( answer ), IPC_GET_ARG2( answer ), IPC_GET_ARG3( answer ));

                    continue;

            case 4:     ipc_answer_4( callid, res, IPC_GET_ARG1( answer ), IPC_GET_ARG2( answer ), IPC_GET_ARG3( answer ), IPC_GET_ARG4( answer ));

                    continue;

            default:    ipc_answer_5( callid, res, IPC_GET_ARG1( answer ), IPC_GET_ARG2( answer ), IPC_GET_ARG3( answer ), IPC_GET_ARG4( answer ), IPC_GET_ARG5( answer ));

                    continue;

        }

    }

    socket_cores_destroy( & local_sockets );

    return EOK;

}

int udp_sendto_message( socket_cores_ref local_sockets, int socket_id, void * addr, size_t addrlen, int fragments, int flags ){

    ERROR_DECLARE;

    socket_core_ref         socket;

    struct sockaddr *       address;

    struct sockaddr_in *    address_in;

    packet_t                packet;

    packet_t                next_packet;

    udp_header_ref          header;

    int                     index;

    int                     total_length;

    int                     length;

    if( addrlen < sizeof( struct sockaddr )) return EINVAL;

    address = ( struct sockaddr * ) addr;

    switch( address->sa_family ){

        case AF_INET:

            if( addrlen != sizeof( struct sockaddr_in )) return EINVAL;

            address_in = ( struct sockaddr_in * ) addr;

            socket = socket_cores_find( local_sockets, socket_id );

            if( ! socket ) return ENOTSOCK;

            // bind the socket to a random free port if not bound

            if( socket->port <= 0 ){

                // try to find a free port

                fibril_rwlock_read_unlock( & udp_globals.lock );

                fibril_rwlock_write_lock( & udp_globals.lock );

                ERROR_PROPAGATE( socket_bind_free_port( & udp_globals.sockets, socket, UDP_FREE_PORTS_START, UDP_FREE_PORTS_END, udp_globals.last_used_port ));

                fibril_rwlock_write_unlock( & udp_globals.lock );

                fibril_rwlock_read_lock( & udp_globals.lock );

                // set the next port as the search starting port number

                udp_globals.last_used_port = socket->port;

            }

            // TODO do not ask all the time

            ERROR_PROPAGATE( ip_packet_size_req( udp_globals.ip_phone, -1, & udp_globals.addr_len, & udp_globals.prefix, & udp_globals.content, & udp_globals.suffix ));

            // read the first packet fragment

            total_length = socket_read_packet_data( & packet, sizeof( udp_header_t ), address_in );

            if( total_length < 0 ) return total_length;

            // prefix the udp header

            header = PACKET_PREFIX( packet, udp_header_t );

            if( ! header ){

                pq_release( udp_globals.net_phone, packet_get_id( packet ));

                return ENOMEM;

            }

            // read the rest of the packet fragments

            for( index = 1; index < fragments; ++ index ){

                length = socket_read_packet_data( & next_packet, 0, address_in );

                if( length < 0 ){

                    pq_release( udp_globals.net_phone, packet_get_id( packet ));

                    return length;

                }

                packet = pq_add( packet, next_packet, index, 0 );

                total_length += length;

            }

            // set the udp header

            header->source = ( socket->port < 0 ) ? 0 : htons( socket->port );

            header->dest = htons( address_in->sin_port );

            header->len = htons( total_length + sizeof( udp_header_t ));

            // TODO my ip address for the pseudo header checksum

            header->check = 0;

            // prepare the first packet fragment

            if( ERROR_OCCURRED( ip_client_prepare_packet( packet, IPPROTO_UDP, 0, 0, 0, 0 ))){

                pq_release( udp_globals.net_phone, packet_get_id( packet ));

                return ERROR_CODE;

            }

            // send the packet

            return ip_send_msg( udp_globals.ip_phone, socket->device_id, packet, SERVICE_UDP, 0 );

        // TODO IPv6

        default:

            return EAFNOSUPPORT;

    }

    return EOK;

}

int udp_recvfrom_message( socket_cores_ref local_sockets, int socket_id, int flags ){

    ERROR_DECLARE;

    socket_core_ref socket;

    int             packet_id;

    packet_t        packet;

    udp_header_ref  header;

    struct sockaddr_in      address;

    int             length;

    packet_t        next_packet;

    void *          data;

    int             fragments;

    int *           lengths;

    int             index;

    uint8_t *       addr;

    // find the socket

    socket = socket_cores_find( local_sockets, socket_id );

    if( ! socket ) return ENOTSOCK;

    // get the next received packet

    packet_id = dyn_fifo_value( & socket->received );

    if( packet_id < 0 ) return NO_DATA;

    ERROR_PROPAGATE( packet_translate( udp_globals.net_phone, & packet, packet_id ));

    // get udp header

    data = packet_get_data( packet );

    if( ! data ){

        pq_release( udp_globals.net_phone, packet_id );

        return NO_DATA;

    }

    header = ( udp_header_ref ) data;

    // set the source address

    address.sin_family = PF_INET;

    address.sin_port = ntohs( header->source );

    length = packet_get_addr( packet, & addr, NULL );

    if( length != sizeof( address.sin_addr.s_addr )){

        pq_release( udp_globals.net_phone, packet_id );

        return EINVAL;

    }

    address.sin_addr.s_addr = *(( uint32_t * ) addr );

    bzero( & address.sin_zero, sizeof( address.sin_zero ));

    // send the source address

    ERROR_PROPAGATE( socket_write_data( & address, sizeof( address )));

    next_packet = pq_next( packet );

    if( ! next_packet ){

        // write all if only one fragment

        ERROR_PROPAGATE( socket_write_data( data + sizeof( udp_header_t ), packet_get_data_length( packet ) - sizeof( udp_header_t )));

        // store the total length

        length = packet_get_data_length( packet ) - sizeof( udp_header_t );

    }else{

        // count the packet fragments

        fragments = 1;

        next_packet = pq_next( packet );

        while(( next_packet = pq_next( next_packet ))){

            ++ fragments;

        }

        // compute and store the fragment lengths

        lengths = ( int * ) malloc( sizeof( int ) * ( fragments + 1 ));

        if( ! lengths ) return ENOMEM;

        lengths[ 0 ] = packet_get_data_length( packet ) - sizeof( udp_header_t );

        lengths[ fragments ] = lengths[ 0 ];

        next_packet = pq_next( packet );

        for( index = 1; index < fragments; ++ index ){

            lengths[ index ] = packet_get_data_length( next_packet );

            lengths[ fragments ] += lengths[ index ];

            next_packet = pq_next( packet );

        }while( next_packet );

        // write the fragment lengths

        ERROR_PROPAGATE( socket_write_data( lengths, sizeof( int ) * ( fragments + 1 )));

        // write the first fragment

        ERROR_PROPAGATE( socket_write_data( data + sizeof( udp_header_t ), lengths[ 0 ] ));

        next_packet = pq_next( packet );

        // write the rest of the fragments

        for( index = 1; index < fragments; ++ index ){

            ERROR_PROPAGATE( socket_write_data( packet_get_data( next_packet ), lengths[ index ] ));

            next_packet = pq_next( packet );

        }while( next_packet );

        // store the total length

        length = lengths[ fragments ];

        free( lengths );

    }

    // release the packet

    dyn_fifo_pop( & socket->received );

    pq_release( udp_globals.net_phone, packet_get_id( packet ));

    // return the total length

    return length;

}

int socket_write_data( void * data, size_t data_length ){

    size_t          length;

    ipc_callid_t    callid;

    if(( ! ipc_data_read_receive( & callid, & length ))

    || ( length < data_length )){

        return EINVAL;

    }

    return ipc_data_read_finalize( callid, data, data_length );

}

int socket_read_data( void ** data, size_t * length ){

    ERROR_DECLARE;

    ipc_callid_t    callid;

    if( !( data && length )) return EBADMEM;

    if( ! ipc_data_write_receive( & callid, length )) return EINVAL;

    * data = malloc( * length );

    if( !( * data )) return ENOMEM;

    if( ERROR_OCCURRED( ipc_data_write_finalize( callid, * data, * length ))){

        free( data );

        return ERROR_CODE;

    }

    return EOK;

}

int socket_read_packet_data( packet_ref packet, size_t prefix, struct sockaddr_in * address_in ){

    ERROR_DECLARE;

    ipc_callid_t    callid;

    size_t          length;

    void *          data;

    // get the data length

    if( ! ipc_data_write_receive( & callid, & length )) return EINVAL;

    // get a new packet

    * packet = packet_get_4( udp_globals.net_phone, length, udp_globals.addr_len, prefix + udp_globals.prefix, udp_globals.suffix );

    if( ! packet ) return ENOMEM;

    // allocate space in the packet

    data = packet_suffix( * packet, length );

    if( ! data ){

        pq_release( udp_globals.net_phone, packet_get_id( * packet ));

        return ENOMEM;

    }

    // read the data into the packet

    if( ERROR_OCCURRED( ipc_data_write_finalize( callid, data, length ))

    // set the packet destination address

    || ERROR_OCCURRED( packet_set_addr( * packet, NULL, ( uint8_t * ) & address_in->sin_addr.s_addr, sizeof( address_in->sin_addr.s_addr )))){

        pq_release( udp_globals.net_phone, packet_get_id( * packet ));

        return ERROR_CODE;

    }

    return length;

}

static int  release_and_return( packet_t packet, int result ){

    pq_release( udp_globals.net_phone, packet_get_id( packet ));

    return result;

}

void udp_send_icmp_port_unreachable( packet_t packet, services_t error ){

    packet_t    next;

    uint8_t *   src;

    int         length;

    // detach the first packet and release the others

    next = pq_detach( packet );

    if( next ){

        pq_release( udp_globals.net_phone, packet_get_id( next ));

    }

    length = packet_get_addr( packet, & src, NULL );

    if(( length > 0 )

    && ( ! error )

    && ( udp_globals.icmp_phone >= 0 )

    // set both addresses to the source one (avoids the source address deletion before setting the destination one)

    && ( packet_set_addr( packet, src, src, length ) == EOK )){

        icmp_destination_unreachable_msg( udp_globals.icmp_phone, ICMP_PORT_UNREACH, 0, packet );

    }else{

        return release_and_return( packet, EINVAL );

    }

}

/** @}

 */