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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 socket
 *  @{
 */

/** @file
 *  Socket application program interface (API) implementation.
 *  @see socket.h for more information.
 *  This is a part of the network application library.
 */

#include <assert.h>
#include <async.h>
#include <fibril_sync.h>

#include <ipc/services.h>

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

#include "../include/in.h"
#include "../include/socket.h"
#include "../include/socket_errno.h"

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

#include "socket_messages.h"

/** Initial received packet queue size.
 */
#define SOCKET_INITIAL_RECEIVED_SIZE    4

/** Maximum received packet queue size.
 */
#define SOCKET_MAX_RECEIVED_SIZE        64

/** Initial waiting sockets queue size.
 */
#define SOCKET_INITIAL_ACCEPTED_SIZE    1

/** Maximum waiting sockets queue size.
 */
#define SOCKET_MAX_ACCEPTED_SIZE        64

/** Type definition of the socket specific data.
 *  @see socket
 */
typedef struct socket   socket_t;

/** Type definition of the socket specific data pointer.
 *  @see socket
 */
typedef socket_t *  socket_ref;

/** Socket specific data.
 *  Each socket lock locks only its structure part and any number of them may be locked simultaneously.
 */
struct socket{
    /** Socket identifier.
     */
    int                 socket_id;
    /** Parent module phone.
     */
    int                 phone;
    /** Parent module service.
     */
    services_t          service;
    /** Underlying protocol header size.
     *  Sending and receiving optimalization.
     */
    size_t              header_size;
    /** Packet data fragment size.
     *  Sending optimalization.
     */
    size_t              data_fragment_size;
    /** Sending safety lock.
     *  Locks the header_size and data_fragment_size attributes.
     */
    fibril_rwlock_t     sending_lock;
    /** Received packets queue.
     */
    dyn_fifo_t          received;
    /** Received packets safety lock.
     *  Used for receiving and receive notifications.
     *  Locks the received attribute.
     */
    fibril_mutex_t      receive_lock;
    /** Received packets signaling.
     *  Signaled upon receive notification.
     */
    fibril_condvar_t    receive_signal;
    /** Waiting sockets queue.
     */
    dyn_fifo_t          accepted;
    /** Waiting sockets safety lock.
     *  Used for accepting and accept notifications.
     *  Locks the accepted attribute.
     */
    fibril_mutex_t      accept_lock;
    /** Waiting sockets signaling.
     *  Signaled upon accept notification.
     */
    fibril_condvar_t    accept_signal;
    /** The number of blocked functions called.
     *  Used while waiting for the received packets or accepted sockets.
     */
    int                 blocked;
};

/** Sockets map.
 *  Maps socket identifiers to the socket specific data.
 *  @see int_map.h
 */
INT_MAP_DECLARE( sockets, socket_t );

/** Socket client library global data.
 */
static struct socket_client_globals {
    /** TCP module phone.
     */
    int tcp_phone;
    /** UDP module phone.
     */
    int udp_phone;
    /** Active sockets.
     */
    sockets_ref sockets;
    /** Safety lock.
     *  Write lock is used only for adding or removing sockets.
     *  When locked for writing, no other socket locks need to be locked.
     *  When locked for reading, any other socket locks may be locked.
     *  No socket lock may be locked if this lock is unlocked.
     */
    fibril_rwlock_t lock;
} socket_globals = {
    .tcp_phone = -1,
    .udp_phone = -1,
    .sockets = NULL,
    .lock = {
        .readers = 0,
        .writers = 0,
        .waiters = {
            .prev = & socket_globals.lock.waiters,
            .next = & socket_globals.lock.waiters
        }
    }
};

INT_MAP_IMPLEMENT( sockets, socket_t );

/** Returns the TCP module phone.
 *  Connects to the TCP module if necessary.
 *  @returns The TCP module phone.
 */
static int  socket_get_tcp_phone( void );

/** Returns the UDP module phone.
 *  Connects to the UDP module if necessary.
 *  @returns The UDP module phone.
 */
static int  socket_get_udp_phone( void );

/** Returns the active sockets.
 *  @returns The active sockets.
 */
static sockets_ref  socket_get_sockets( void );

/** Default thread for new connections.
 *  @param iid The initial message identifier. Input parameter.
 *  @param icall The initial message call structure. Input parameter.
 */
void    socket_connection( ipc_callid_t iid, ipc_call_t * icall );

/** Sends message to the socket parent module with specified data.
 *  @param socket_id Socket identifier. Input parameter.
 *  @param message The action message. Input parameter.
 *  @param arg2 The second message parameter. Input parameter.
 *  @param data The data to be sent. Input parameter.
 *  @param datalength The data length. Input parameter.
 *  @returns EOK on success.
 *  @returns ENOTSOCK if the socket is not found.
 *  @returns EBADMEM if the data parameter is NULL.
 *  @returns NO_DATA if the datalength parameter is zero (0).
 *  @returns Other error codes as defined for the spcific message.
 */
int socket_send_data( int socket_id, ipcarg_t message, ipcarg_t arg2, const void * data, size_t datalength );

/** Initializes a new socket specific data.
 *  @param socket The socket to be initialized. Input/output parameter.
 *  @param socket_id The new socket identifier. Input parameter.
 *  @param phone The parent module phone. Input parameter.
 *  @param service The parent module service. Input parameter.
 */
void    socket_initialize( socket_ref socket, int socket_id, int phone, services_t service );

/** Clears and destroys the socket.
 *  @param socket The socket to be destroyed. Input parameter.
 */
void    socket_destroy( socket_ref socket );

/** Receives data via the socket.
 *  @param message The action message. Input parameter.
 *  @param socket_id Socket identifier. Input parameter.
 *  @param data The data buffer to be filled. Output parameter.
 *  @param datalength The data length. Input parameter.
 *  @param flags Various receive flags. Input parameter.
 *  @param fromaddr The source address. May be NULL for connected sockets. Output parameter.
 *  @param addrlen The address length. The maximum address length is read. The actual address length is set. Used only if fromaddr is not NULL. Input/output parameter.
 *  @returns EOK on success.
 *  @returns ENOTSOCK if the socket is not found.
 *  @returns EBADMEM if the data parameter is NULL.
 *  @returns NO_DATA if the datalength or addrlen parameter is zero (0).
 *  @returns Other error codes as defined for the spcific message.
 */
int recvfrom_core( ipcarg_t message, int socket_id, void * data, size_t datalength, int flags, struct sockaddr * fromaddr, socklen_t * addrlen );

/** Sends data via the socket to the remote address.
 *  Binds the socket to a free port if not already connected/bound.
 *  @param message The action message. Input parameter.
 *  @param socket_id Socket identifier. Input parameter.
 *  @param data The data to be sent. Input parameter.
 *  @param datalength The data length. Input parameter.
 *  @param flags Various send flags. Input parameter.
 *  @param toaddr The destination address. May be NULL for connected sockets. Input parameter.
 *  @param addrlen The address length. Used only if toaddr is not NULL. Input parameter.
 *  @returns EOK on success.
 *  @returns ENOTSOCK if the socket is not found.
 *  @returns EBADMEM if the data or toaddr parameter is NULL.
 *  @returns NO_DATA if the datalength or the addrlen parameter is zero (0).
 *  @returns Other error codes as defined for the NET_SOCKET_SENDTO message.
 */
int sendto_core( ipcarg_t message, int socket_id, const void * data, size_t datalength, int flags, const struct sockaddr * toaddr, socklen_t addrlen );

static int socket_get_tcp_phone( void ){
    if( socket_globals.tcp_phone < 0 ){
        socket_globals.tcp_phone = bind_service( SERVICE_TCP, 0, 0, SERVICE_TCP, socket_connection );
    }
    return socket_globals.tcp_phone;
}

static int socket_get_udp_phone( void ){
    if( socket_globals.udp_phone < 0 ){
        socket_globals.udp_phone = bind_service( SERVICE_UDP, 0, 0, SERVICE_UDP, socket_connection );
    }
    return socket_globals.udp_phone;
}

static sockets_ref socket_get_sockets( void ){
    if( ! socket_globals.sockets ){
        socket_globals.sockets = ( sockets_ref ) malloc( sizeof( sockets_t ));
        if( ! socket_globals.sockets ) return NULL;
        if( sockets_initialize( socket_globals.sockets ) != EOK ){
            free( socket_globals.sockets );
            socket_globals.sockets = NULL;
        }
    }
    return socket_globals.sockets;
}

void socket_initialize( socket_ref socket, int socket_id, int phone, services_t service ){
    socket->socket_id = socket_id;
    socket->phone = phone;
    socket->service = service;
    dyn_fifo_initialize( & socket->received, SOCKET_INITIAL_RECEIVED_SIZE );
    dyn_fifo_initialize( & socket->accepted, SOCKET_INITIAL_ACCEPTED_SIZE );
    fibril_mutex_initialize( & socket->receive_lock );
    fibril_condvar_initialize( & socket->receive_signal );
    fibril_mutex_initialize( & socket->accept_lock );
    fibril_condvar_initialize( & socket->accept_signal );
    fibril_rwlock_initialize( & socket->sending_lock );
}

void socket_connection( ipc_callid_t iid, ipc_call_t * icall ){
    ERROR_DECLARE;

    ipc_callid_t    callid;
    ipc_call_t      call;
    socket_ref      socket;
    socket_ref      new_socket;

    while( true ){

        callid = async_get_call( & call );
        switch( IPC_GET_METHOD( call )){
                // TODO remember the data_fragment_size
            case NET_SOCKET_RECEIVED:
                fibril_rwlock_read_lock( & socket_globals.lock );
                // find the socket
                socket = sockets_find( socket_get_sockets(), SOCKET_GET_SOCKET_ID( call ));
                if( ! socket ){
                    ERROR_CODE = ENOTSOCK;
                }else{
                    fibril_mutex_lock( & socket->receive_lock );
                    // push the number of received packet fragments
                    if( ! ERROR_OCCURRED( dyn_fifo_push( & socket->received, SOCKET_GET_DATA_FRAGMENTS( call ), SOCKET_MAX_RECEIVED_SIZE ))){
                        // signal the received packet
                        fibril_condvar_signal( & socket->receive_signal );
                    }
                    fibril_mutex_unlock( & socket->receive_lock );
                }
                fibril_rwlock_read_unlock( & socket_globals.lock );
                break;
            case NET_SOCKET_ACCEPTED:
                fibril_rwlock_read_lock( & socket_globals.lock );
                // find the socket
                socket = sockets_find( socket_get_sockets(), SOCKET_GET_SOCKET_ID( call ));
                if( ! socket ){
                    ERROR_CODE = ENOTSOCK;
                }else{
                    // create a new scoket
                    new_socket = ( socket_ref ) malloc( sizeof( socket_t ));
                    if( ! new_socket ){
                        ERROR_CODE = ENOMEM;
                    }else{
                        bzero( socket, sizeof( * socket ));
                        socket_initialize( new_socket, SOCKET_GET_SOCKET_ID( call ), socket->phone, socket->service );
                        ERROR_CODE = sockets_add( socket_get_sockets(), new_socket->socket_id, new_socket );
                        if( ERROR_CODE < 0 ){
                            free( new_socket );
                        }else{
                            // push the new socket identifier
                            fibril_mutex_lock( & socket->accept_lock );
                            if( ERROR_OCCURRED( dyn_fifo_push( & socket->accepted, new_socket->socket_id, SOCKET_MAX_ACCEPTED_SIZE ))){
                                sockets_exclude( socket_get_sockets(), new_socket->socket_id );
                                free( new_socket );
                            }else{
                                // signal the accepted socket
                                fibril_condvar_signal( & socket->accept_signal );
                            }
                            fibril_mutex_unlock( & socket->accept_lock );
                            ERROR_CODE = EOK;
                        }
                    }
                }
                fibril_rwlock_read_unlock( & socket_globals.lock );
                break;
            // TODO obsolete?
            case NET_SOCKET_DATA_FRAGMENT_SIZE:
                fibril_rwlock_read_lock( & socket_globals.lock );
                // find the socket
                socket = sockets_find( socket_get_sockets(), SOCKET_GET_SOCKET_ID( call ));
                if( ! socket ){
                    ERROR_CODE = ENOTSOCK;
                }else{
                    fibril_rwlock_write_lock( & socket->sending_lock );
                    // set the data fragment size
                    socket->data_fragment_size = SOCKET_GET_DATA_FRAGMENT_SIZE( call );
                    fibril_rwlock_write_unlock( & socket->sending_lock );
                    ERROR_CODE = EOK;
                }
                fibril_rwlock_read_unlock( & socket_globals.lock );
                break;
            default:
                ERROR_CODE = ENOTSUP;
        }
        ipc_answer_0( callid, ( ipcarg_t ) ERROR_CODE );
    }
}

int socket( int domain, int type, int protocol ){
    ERROR_DECLARE;

    socket_ref  socket;
    int         phone;
    int         socket_id;
    services_t  service;

    // find the appropriate service
    switch( domain ){
        case PF_INET:
            switch( type ){
                case SOCK_STREAM:
                    if( ! protocol ) protocol = IPPROTO_TCP;
                    switch( protocol ){
                        case IPPROTO_TCP:
                            phone = socket_get_tcp_phone();
                            service = SERVICE_TCP;
                            break;
                        default:
                            return EPROTONOSUPPORT;
                    }
                    break;
                case SOCK_DGRAM:
                    if( ! protocol ) protocol = IPPROTO_UDP;
                    switch( protocol ){
                        case IPPROTO_UDP:
                            phone = socket_get_udp_phone();
                            service = SERVICE_UDP;
                            break;
                        default:
                            return EPROTONOSUPPORT;
                    }
                    break;
                case SOCK_RAW:
                default:
                    return ESOCKTNOSUPPORT;
            }
            break;
        // TODO IPv6
        default:
            return EPFNOSUPPORT;
    }
    // create a new socket structure
    socket = ( socket_ref ) malloc( sizeof( socket_t ));
    if( ! socket ) return ENOMEM;
    bzero( socket, sizeof( * socket ));
    // request a new socket
    if( ERROR_OCCURRED(( int ) async_req_3_3( phone, NET_SOCKET, 0, 0, service, ( ipcarg_t * ) & socket_id, ( ipcarg_t * ) & socket->data_fragment_size, ( ipcarg_t * ) & socket->header_size ))){
        free( socket );
        return ERROR_CODE;
    }
    // finish the new socket initialization
    socket_initialize( socket, socket_id, phone, service );
    // store the new socket
    fibril_rwlock_write_lock( & socket_globals.lock );
    ERROR_CODE = sockets_add( socket_get_sockets(), socket_id, socket );
    fibril_rwlock_write_unlock( & socket_globals.lock );
    if( ERROR_CODE < 0 ){
        dyn_fifo_destroy( & socket->received );
        dyn_fifo_destroy( & socket->accepted );
        free( socket );
        async_msg_3( phone, NET_SOCKET_CLOSE, ( ipcarg_t ) socket_id, 0, service );
        return ERROR_CODE;
    }

    return socket_id;
}

int socket_send_data( int socket_id, ipcarg_t message, ipcarg_t arg2, const void * data, size_t datalength ){
    socket_ref      socket;
    aid_t           message_id;
    ipcarg_t        result;

    if( ! data ) return EBADMEM;
    if( ! datalength ) return NO_DATA;

    fibril_rwlock_read_lock( & socket_globals.lock );
    // find the socket
    socket = sockets_find( socket_get_sockets(), socket_id );
    if( ! socket ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        return ENOTSOCK;
    }
    // request the message
    message_id = async_send_3( socket->phone, message, ( ipcarg_t ) socket->socket_id, arg2, socket->service, NULL );
    // send the address
    ipc_data_write_start( socket->phone, data, datalength );
    fibril_rwlock_read_unlock( & socket_globals.lock );
    async_wait_for( message_id, & result );
    return ( int ) result;
}

int bind( int socket_id, const struct sockaddr * my_addr, socklen_t addrlen ){
    if( addrlen <= 0 ) return EINVAL;
    // send the address
    return socket_send_data( socket_id, NET_SOCKET_BIND, 0, my_addr, ( size_t ) addrlen );
}

int listen( int socket_id, int backlog ){
    socket_ref  socket;
    int         result;

    if( backlog <= 0 ) return EINVAL;
    fibril_rwlock_read_lock( & socket_globals.lock );
    // find the socket
    socket = sockets_find( socket_get_sockets(), socket_id );
    if( ! socket ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        return ENOTSOCK;
    }
    // request listen backlog change
    result = ( int ) async_req_3_0( socket->phone, NET_SOCKET_LISTEN, ( ipcarg_t ) socket->socket_id, ( ipcarg_t ) backlog, socket->service );
    fibril_rwlock_read_unlock( & socket_globals.lock );
    return result;
}

int accept( int socket_id, struct sockaddr * cliaddr, socklen_t * addrlen ){
    socket_ref      socket;
    aid_t           message_id;
    int             result;

    if(( ! cliaddr ) || ( ! addrlen )) return EBADMEM;

    fibril_rwlock_read_lock( & socket_globals.lock );
    // find the socket
    socket = sockets_find( socket_get_sockets(), socket_id );
    if( ! socket ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        return ENOTSOCK;
    }
    fibril_mutex_lock( & socket->accept_lock );
    // wait for an accepted socket
    ++ socket->blocked;
    while( dyn_fifo_value( & socket->accepted ) <= 0 ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        fibril_condvar_wait( & socket->accept_signal, & socket->accept_lock );
        fibril_rwlock_read_lock( & socket_globals.lock );
    }
    -- socket->blocked;
    // request accept
    message_id = async_send_3( socket->phone, NET_SOCKET_ACCEPT, ( ipcarg_t ) socket->socket_id, ( ipcarg_t ) dyn_fifo_value( & socket->accepted ), socket->service, NULL );
    // read address
    ipc_data_read_start( socket->phone, cliaddr, * addrlen );
    fibril_rwlock_read_unlock( & socket_globals.lock );
    async_wait_for( message_id, ( ipcarg_t * ) & result );
    if( result > 0 ){
        // dequeue the accepted apcket if successful
        dyn_fifo_pop( & socket->accepted );
    }
    fibril_mutex_unlock( & socket->accept_lock );
    return result;
}

int connect( int socket_id, const struct sockaddr * serv_addr, socklen_t addrlen ){
    if( ! serv_addr ) return EDESTADDRREQ;
    if( ! addrlen ) return EDESTADDRREQ;
    // send the address
    return socket_send_data( socket_id, NET_SOCKET_CONNECT, 0, serv_addr, addrlen );
}

int closesocket( int socket_id ){
    ERROR_DECLARE;

    socket_ref      socket;

    fibril_rwlock_write_lock( & socket_globals.lock );
    socket = sockets_find( socket_get_sockets(), socket_id );
    if( ! socket ){
        fibril_rwlock_write_unlock( & socket_globals.lock );
        return ENOTSOCK;
    }
    if( socket->blocked ){
        fibril_rwlock_write_unlock( & socket_globals.lock );
        return EINPROGRESS;
    }
    // request close
    ERROR_PROPAGATE(( int ) async_req_3_0( socket->phone, NET_SOCKET_CLOSE, ( ipcarg_t ) socket->socket_id, 0, socket->service ));
    // free the socket structure
    socket_destroy( socket );
    fibril_rwlock_write_unlock( & socket_globals.lock );
    return EOK;
}

void socket_destroy( socket_ref socket ){
    int accepted_id;

    // destroy all accepted sockets
    while(( accepted_id = dyn_fifo_pop( & socket->accepted )) >= 0 ){
        socket_destroy( sockets_find( socket_get_sockets(), accepted_id ));
    }
    dyn_fifo_destroy( & socket->received );
    dyn_fifo_destroy( & socket->accepted );
    sockets_exclude( socket_get_sockets(), socket->socket_id );
}

int send( int socket_id, void * data, size_t datalength, int flags ){
    // without the address
    return sendto_core( NET_SOCKET_SEND, socket_id, data, datalength, flags, NULL, 0 );
}

int sendto( int socket_id, const void * data, size_t datalength, int flags, const struct sockaddr * toaddr, socklen_t addrlen ){
    if( ! toaddr ) return EDESTADDRREQ;
    if( ! addrlen ) return EDESTADDRREQ;
    // with the address
    return sendto_core( NET_SOCKET_SENDTO, socket_id, data, datalength, flags, toaddr, addrlen );
}

int sendto_core( ipcarg_t message, int socket_id, const void * data, size_t datalength, int flags, const struct sockaddr * toaddr, socklen_t addrlen ){
    socket_ref      socket;
    aid_t           message_id;
    ipcarg_t        result;
    size_t          fragments;

    if( ! data ) return EBADMEM;
    if( ! datalength ) return NO_DATA;
    fibril_rwlock_read_lock( & socket_globals.lock );
    // find socket
    socket = sockets_find( socket_get_sockets(), socket_id );
    if( ! socket ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        return ENOTSOCK;
    }
    fibril_rwlock_read_lock( & socket->sending_lock );
    // compute data fragment count
    fragments = ( datalength + socket->header_size ) / socket->data_fragment_size;
    if(( datalength + socket->header_size ) % socket->data_fragment_size ) ++ fragments;
    // request send
    message_id = async_send_5( socket->phone, message, ( ipcarg_t ) socket->socket_id, socket->data_fragment_size, socket->service, ( ipcarg_t ) flags, fragments, NULL );
    // send the address if given
    if(( ! toaddr ) || ( ipc_data_write_start( socket->phone, toaddr, addrlen ) == EOK )){
        if( fragments == 1 ){
            // send all if only one fragment
            ipc_data_write_start( socket->phone, data, datalength );
        }else{
            // send the first fragment
            ipc_data_write_start( socket->phone, data, socket->data_fragment_size - socket->header_size );
            data = (( const uint8_t * ) data ) + socket->data_fragment_size - socket->header_size;
            // send the middle fragments
            while(( -- fragments ) > 1 ){
                ipc_data_write_start( socket->phone, data, socket->data_fragment_size );
                data = (( const uint8_t * ) data ) + socket->data_fragment_size;
            }
            // send the last fragment
            ipc_data_write_start( socket->phone, data, ( datalength + socket->header_size ) % socket->data_fragment_size );
        }
    }
    fibril_rwlock_read_unlock( & socket->sending_lock );
    fibril_rwlock_read_unlock( & socket_globals.lock );
    async_wait_for( message_id, & result );
    return ( int ) result;
}

int recv( int socket_id, void * data, size_t datalength, int flags ){
    // without the address
    return recvfrom_core( NET_SOCKET_RECV, socket_id, data, datalength, flags, NULL, NULL );
}

int recvfrom( int socket_id, void * data, size_t datalength, int flags, struct sockaddr * fromaddr, socklen_t * addrlen ){
    if( ! fromaddr ) return EBADMEM;
    if( ! addrlen ) return NO_DATA;
    // with the address
    return recvfrom_core( NET_SOCKET_RECVFROM, socket_id, data, datalength, flags, fromaddr, addrlen );
}

int recvfrom_core( ipcarg_t message, int socket_id, void * data, size_t datalength, int flags, struct sockaddr * fromaddr, socklen_t * addrlen ){
    socket_ref      socket;
    aid_t           message_id;
    int             result;
    size_t          fragments;
    size_t *        lengths;
    size_t          index;
    ipc_call_t      answer;

    if( ! data ) return EBADMEM;
    if( ! datalength ) return NO_DATA;
    if( fromaddr && ( ! addrlen )) return EINVAL;
    fibril_rwlock_read_lock( & socket_globals.lock );
    // find the socket
    socket = sockets_find( socket_get_sockets(), socket_id );
    if( ! socket ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        return ENOTSOCK;
    }
    fibril_mutex_lock( & socket->receive_lock );
    // wait for a received packet
    ++ socket->blocked;
    while(( result = dyn_fifo_value( & socket->received )) <= 0 ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        fibril_condvar_wait( & socket->receive_signal, & socket->receive_lock );
        fibril_rwlock_read_lock( & socket_globals.lock );
    }
    -- socket->blocked;
    fragments = ( size_t ) result;
    // prepare lengths if more fragments
    if( fragments > 1 ){
        lengths = ( size_t * ) malloc( sizeof( size_t ) * fragments + sizeof( size_t ));
        if( ! lengths ){
            fibril_mutex_unlock( & socket->receive_lock );
            fibril_rwlock_read_unlock( & socket_globals.lock );
            return ENOMEM;
        }
        // request packet data
        message_id = async_send_4( socket->phone, message, ( ipcarg_t ) socket->socket_id, 0, socket->service, ( ipcarg_t ) flags, & answer );
        // read the address if desired
        if(( ! fromaddr ) || ( ipc_data_read_start( socket->phone, fromaddr, * addrlen ) == EOK )){
        // read the fragment lengths
            if( ipc_data_read_start( socket->phone, lengths, sizeof( int ) * ( fragments + 1 )) == EOK ){
                if( lengths[ fragments ] <= datalength ){
                    // read all fragments if long enough
                    for( index = 0; index < fragments; ++ index ){
                        ipc_data_read_start( socket->phone, data, lengths[ index ] );
                        data = (( uint8_t * ) data ) + lengths[ index ];
                    }
                }
            }
        }
        free( lengths );
    }else{
        // request packet data
        message_id = async_send_4( socket->phone, message, ( ipcarg_t ) socket->socket_id, 0, socket->service, ( ipcarg_t ) flags, & answer );
        // read the address if desired
        if(( ! fromaddr ) || ( ipc_data_read_start( socket->phone, fromaddr, * addrlen ) == EOK )){
            // read all if only one fragment
            ipc_data_read_start( socket->phone, data, datalength );
        }
    }
    async_wait_for( message_id, ( ipcarg_t * ) & result );
    // if successful
    if( result == EOK ){
        // dequeue the received packet
        dyn_fifo_pop( & socket->received );
        // return read data length
        result = SOCKET_GET_READ_DATA_LENGTH( answer );
        // set address length
        if( fromaddr && addrlen ) * addrlen = SOCKET_GET_ADDRESS_LENGTH( answer );
    }
    fibril_mutex_unlock( & socket->receive_lock );
    fibril_rwlock_read_unlock( & socket_globals.lock );
    return result;
}

int getsockopt( int socket_id, int level, int optname, void * value, size_t * optlen ){
    socket_ref      socket;
    aid_t           message_id;
    ipcarg_t        result;

    if( !( value && optlen )) return EBADMEM;
    if( !( * optlen )) return NO_DATA;
    fibril_rwlock_read_lock( & socket_globals.lock );
    // find the socket
    socket = sockets_find( socket_get_sockets(), socket_id );
    if( ! socket ){
        fibril_rwlock_read_unlock( & socket_globals.lock );
        return ENOTSOCK;
    }
    // request option value
    message_id = async_send_3( socket->phone, NET_SOCKET_GETSOCKOPT, ( ipcarg_t ) socket->socket_id, ( ipcarg_t ) optname, socket->service, NULL );
    // read the length
    if( ipc_data_read_start( socket->phone, optlen, sizeof( * optlen )) == EOK ){
        // read the value
        ipc_data_read_start( socket->phone, value, * optlen );
    }
    fibril_rwlock_read_unlock( & socket_globals.lock );
    async_wait_for( message_id, & result );
    return ( int ) result;
}

int setsockopt( int socket_id, int level, int optname, const void * value, size_t optlen ){
    // send the value
    return socket_send_data( socket_id, NET_SOCKET_SETSOCKOPT, ( ipcarg_t ) optname, value, optlen );

}

/** @}
 */