source: mainline/uspace/srv/net/tl/icmp/icmp.c@ 7d31f7c

/*
 * 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 icmp
 *  @{
 */

/** @file
 *  ICMP module implementation.
 *  @see icmp.h
 */

#include <async.h>
#include <atomic.h>
#include <fibril.h>
#include <fibril_synch.h>
#include <stdint.h>

#include <ipc/ipc.h>
#include <ipc/services.h>

#include <sys/time.h>
#include <sys/types.h>

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

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

#include "../../include/byteorder.h"
#include "../../include/checksum.h"
#include "../../include/icmp_api.h"
#include "../../include/icmp_client.h"
#include "../../include/icmp_codes.h"
#include "../../include/icmp_common.h"
#include "../../include/icmp_interface.h"
#include "../../include/il_interface.h"
#include "../../include/inet.h"
#include "../../include/ip_client.h"
#include "../../include/ip_interface.h"
#include "../../include/ip_protocols.h"
#include "../../include/net_interface.h"
#include "../../include/socket_codes.h"
#include "../../include/socket_errno.h"

#include "../../tl/tl_messages.h"

#include "icmp.h"
#include "icmp_header.h"
#include "icmp_messages.h"
#include "icmp_module.h"

/** Default ICMP error reporting.
 */
#define NET_DEFAULT_ICMP_ERROR_REPORTING        true

/** Default ICMP echo replying.
 */
#define NET_DEFAULT_ICMP_ECHO_REPLYING          true

/** Original datagram length in bytes transfered to the error notification message.
 */
#define ICMP_KEEP_LENGTH        8

/** Free identifier numbers pool start.
 */
#define ICMP_FREE_IDS_START     1

/** Free identifier numbers pool end.
 */
#define ICMP_FREE_IDS_END       MAX_UINT16

/** Computes the ICMP datagram checksum.
 *  @param[in,out] header The ICMP datagram header.
 *  @param[in] length The total datagram length.
 *  @returns The computed checksum.
 */
#define ICMP_CHECKSUM( header, length )         htons( ip_checksum(( uint8_t * ) ( header ), ( length )))

/** An echo request datagrams pattern.
 */
#define ICMP_ECHO_TEXT                                  "Hello from HelenOS."

/** Computes an ICMP reply data key.
 *  @param[in] id The message identifier.
 *  @param[in] sequence The message sequence number.
 *  @returns The computed ICMP reply data key.
 */
#define ICMP_GET_REPLY_KEY( id, sequence )      ((( id ) << 16 ) | ( sequence & 0xFFFF ))

/** Processes the received ICMP packet.
 *  Is used as an entry point from the underlying IP module.
 *  Releases the packet on error.
 *  @param device_id The device identifier. Ignored parameter.
 *  @param[in,out] packet The received packet.
 *  @param receiver The target service. Ignored parameter.
 *  @param[in] error The packet error reporting service. Prefixes the received packet.
 *  @returns EOK on success.
 *  @returns Other error codes as defined for the icmp_process_packet() function.
 */
int     icmp_received_msg( device_id_t device_id, packet_t packet, services_t receiver, services_t error );

/** Processes the received ICMP packet.
 *  Notifies the destination socket application.
 *  @param[in,out] packet The received packet.
 *  @param[in] error The packet error reporting service. Prefixes the received packet.
 *  @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     icmp_process_packet( packet_t packet, services_t error );

/** Processes the client messages.
 *  Remembers the assigned identifier and sequence numbers.
 *  Runs until the client module disconnects.
 *  @param[in] callid The message identifier.
 *  @param[in] call The message parameters.
 *  @returns EOK.
 *  @see icmp_interface.h
 *  @see icmp_api.h
 */
int icmp_process_client_messages( ipc_callid_t callid, ipc_call_t call );

/** Processes the generic client messages.
 *  @param[in] call The message parameters.
 *  @returns EOK on success.
 *  @returns ENOTSUP if the message is not known.
 *  @returns Other error codes as defined for the packet_translate() function.
 *  @returns Other error codes as defined for the icmp_destination_unreachable_msg() function.
 *  @returns Other error codes as defined for the icmp_source_quench_msg() function.
 *  @returns Other error codes as defined for the icmp_time_exceeded_msg() function.
 *  @returns Other error codes as defined for the icmp_parameter_problem_msg() function.
 *  @see icmp_interface.h
 */
int     icmp_process_message( ipc_call_t * call );

/** Releases the packet and returns the result.
 *  @param[in] packet The packet queue to be released.
 *  @param[in] result The result to be returned.
 *  @returns The result parameter.
 */
int     icmp_release_and_return( packet_t packet, int result );

/** Requests an echo message.
 *  Sends a packet with specified parameters to the target host and waits for the reply upto the given timeout.
 *  Blocks the caller until the reply or the timeout occurres.
 *  @param[in] id The message identifier.
 *  @param[in] sequence The message sequence parameter.
 *  @param[in] size The message data length in bytes.
 *  @param[in] timeout The timeout in miliseconds.
 *  @param[in] ttl The time to live.
 *  @param[in] tos The type of service.
 *  @param[in] dont_fragment The value indicating whether the datagram must not be fragmented. Is used as a MTU discovery.
 *  @param[in] addr The target host address.
 *  @param[in] addrlen The torget host address length.
 *  @returns ICMP_ECHO on success.
 *  @returns ETIMEOUT if the reply has not arrived before the timeout.
 *  @returns ICMP type of the received error notification. 
 *  @returns EINVAL if the addrlen parameter is less or equal to zero (<=0).
 *  @returns ENOMEM if there is not enough memory left.
 *  @returns EPARTY if there was an internal error.
 */
int     icmp_echo( icmp_param_t id, icmp_param_t sequence, size_t size, mseconds_t timeout, ip_ttl_t ttl, ip_tos_t tos, int dont_fragment, const struct sockaddr * addr, socklen_t addrlen );

/** Prepares the ICMP error packet.
 *  Truncates the original packet if longer than ICMP_KEEP_LENGTH bytes.
 *  Prefixes and returns the ICMP header.
 *  @param[in,out] packet The original packet.
 *  @returns The prefixed ICMP header.
 *  @returns NULL on errors.
 */
icmp_header_ref icmp_prepare_packet( packet_t packet );

/** Sends the ICMP message.
 *  Sets the message type and code and computes the checksum.
 *  Error messages are sent only if allowed in the configuration.
 *  Releases the packet on errors.
 *  @param[in] type The message type.
 *  @param[in] code The message code.
 *  @param[in] packet The message packet to be sent.
 *  @param[in] header The ICMP header.
 *  @param[in] error The error service to be announced. Should be SERVICE_ICMP or zero (0).
 *  @param[in] ttl The time to live.
 *  @param[in] tos The type of service.
 *  @param[in] dont_fragment The value indicating whether the datagram must not be fragmented. Is used as a MTU discovery.
 *  @returns EOK on success.
 *  @returns EPERM if the error message is not allowed.
 */
int     icmp_send_packet( icmp_type_t type, icmp_code_t code, packet_t packet, icmp_header_ref header, services_t error, ip_ttl_t ttl, ip_tos_t tos, int dont_fragment );

/** Tries to set the pending reply result as the received message type.
 *  If the reply data are still present, the reply timeouted and the parent fibril is awaken.
 *  The global lock is not released in this case to be reused by the parent fibril.
 *  Releases the packet.
 *  @param[in] packet The received reply message.
 *  @param[in] header The ICMP message header.
 *  @param[in] type The received reply message type.
 *  @param[in] code The received reply message code.
 *  @returns EOK.
 */
int     icmp_process_echo_reply( packet_t packet, icmp_header_ref header, icmp_type_t type, icmp_code_t code );

/** Assigns a new identifier for the connection.
 *  Fills the echo data parameter with the assigned values.
 *  @param[in,out] echo_data The echo data to be bound.
 *  @returns Index of the inserted echo data.
 *  @returns EBADMEM if the echo_data parameter is NULL.
 *  @returns ENOTCONN if no free identifier have been found.
 */
int     icmp_bind_free_id( icmp_echo_ref echo_data );

/** ICMP global data.
 */
icmp_globals_t  icmp_globals;

INT_MAP_IMPLEMENT( icmp_replies, icmp_reply_t );

INT_MAP_IMPLEMENT( icmp_echo_data, icmp_echo_t );

int icmp_echo_msg( int icmp_phone, size_t size, mseconds_t timeout, ip_ttl_t ttl, ip_tos_t tos, int dont_fragment, const struct sockaddr * addr, socklen_t addrlen ){
        icmp_echo_ref   echo_data;
        int                             res;

        fibril_rwlock_write_lock( & icmp_globals.lock );
        // use the phone as the echo data index
        echo_data = icmp_echo_data_find( & icmp_globals.echo_data, icmp_phone );
        if( ! echo_data ){
                res = ENOENT;
        }else{
                res = icmp_echo( echo_data->identifier, echo_data->sequence_number, size, timeout, ttl, tos, dont_fragment, addr, addrlen );
                if( echo_data->sequence_number < MAX_UINT16 ){
                        ++ echo_data->sequence_number;
                }else{
                        echo_data->sequence_number = 0;
                }
        }
        fibril_rwlock_write_unlock( & icmp_globals.lock );
        return res;
}

int icmp_echo( icmp_param_t id, icmp_param_t sequence, size_t size, mseconds_t timeout, ip_ttl_t ttl, ip_tos_t tos, int dont_fragment, const struct sockaddr * addr, socklen_t addrlen ){
        ERROR_DECLARE;

        icmp_header_ref header;
        packet_t                packet;
        size_t                  length;
        uint8_t *               data;
        icmp_reply_ref                  reply;
        int                             reply_key;
        int                             result;
        int                             index;

        if( addrlen <= 0 ){
                return EINVAL;
        }
        length = ( size_t ) addrlen;
        // TODO do not ask all the time
        ERROR_PROPAGATE( ip_packet_size_req( icmp_globals.ip_phone, -1, & icmp_globals.packet_dimension ));
        packet = packet_get_4( icmp_globals.net_phone, size, icmp_globals.packet_dimension.addr_len, ICMP_HEADER_SIZE + icmp_globals.packet_dimension.prefix, icmp_globals.packet_dimension.suffix );
        if( ! packet ) return ENOMEM;

        // prepare the requesting packet
        // set the destination address
        if( ERROR_OCCURRED( packet_set_addr( packet, NULL, ( const uint8_t * ) addr, length ))){
                return icmp_release_and_return( packet, ERROR_CODE );
        }
        // allocate space in the packet
        data = ( uint8_t * ) packet_suffix( packet, size );
        if( ! data ){
                return icmp_release_and_return( packet, ENOMEM );
        }
        // fill the data
        length = 0;
        while( size > length + sizeof( ICMP_ECHO_TEXT )){
                memcpy( data + length, ICMP_ECHO_TEXT, sizeof( ICMP_ECHO_TEXT ));
                length += sizeof( ICMP_ECHO_TEXT );
        }
        memcpy( data + length, ICMP_ECHO_TEXT, size - length );
        // prefix the header
        header = PACKET_PREFIX( packet, icmp_header_t );
        if( ! header ){
                return icmp_release_and_return( packet, ENOMEM );
        }
        bzero( header, sizeof( * header ));
        header->un.echo.identifier = id;
        header->un.echo.sequence_number = sequence;

        // prepare the reply structure
        reply = malloc( sizeof( * reply ));
        if( ! reply ){
                return icmp_release_and_return( packet, ENOMEM );
        }
        fibril_mutex_initialize( & reply->mutex );
        fibril_mutex_lock( & reply->mutex );
        fibril_condvar_initialize( & reply->condvar );
        reply_key = ICMP_GET_REPLY_KEY( header->un.echo.identifier, header->un.echo.sequence_number );
        index = icmp_replies_add( & icmp_globals.replies, reply_key, reply );
        if( index < 0 ){
                free( reply );
                return icmp_release_and_return( packet, index );
        }

        // unlock the globals and wait for a reply
        fibril_rwlock_write_unlock( & icmp_globals.lock );

        // send the request
        icmp_send_packet( ICMP_ECHO, 0, packet, header, 0, ttl, tos, dont_fragment );

        // wait for a reply
        // timeout in microseconds
        if( ERROR_OCCURRED( fibril_condvar_wait_timeout( & reply->condvar, & reply->mutex, timeout * 1000 ))){
                result = ERROR_CODE;

                // drop the reply mutex
                fibril_mutex_unlock( & reply->mutex );
                // lock the globals again and clean up
                fibril_rwlock_write_lock( & icmp_globals.lock );
        }else{
                // read the result
                result = reply->result;

                // release the reply structure
                fibril_mutex_unlock( & reply->mutex );
        }

        // destroy the reply structure
        icmp_replies_exclude_index( & icmp_globals.replies, index );
        return result;
}

int icmp_destination_unreachable_msg( int icmp_phone, icmp_code_t code, icmp_param_t mtu, packet_t packet ){
        icmp_header_ref header;

        header = icmp_prepare_packet( packet );
        if( ! header ){
                return icmp_release_and_return( packet, ENOMEM );
        }
        if( mtu ){
                header->un.frag.mtu = mtu;
        }
        return icmp_send_packet( ICMP_DEST_UNREACH, code, packet, header, SERVICE_ICMP, 0, 0, 0 );
}

int icmp_source_quench_msg( int icmp_phone, packet_t packet ){
        icmp_header_ref header;

        header = icmp_prepare_packet( packet );
        if( ! header ){
                return icmp_release_and_return( packet, ENOMEM );
        }
        return icmp_send_packet( ICMP_SOURCE_QUENCH, 0, packet, header, SERVICE_ICMP, 0, 0, 0 );
}

int icmp_time_exceeded_msg( int icmp_phone, icmp_code_t code, packet_t packet ){
        icmp_header_ref header;

        header = icmp_prepare_packet( packet );
        if( ! header ){
                return icmp_release_and_return( packet, ENOMEM );
        }
        return icmp_send_packet( ICMP_TIME_EXCEEDED, code, packet, header, SERVICE_ICMP, 0, 0, 0 );
}

int icmp_parameter_problem_msg( int icmp_phone, icmp_code_t code, icmp_param_t pointer, packet_t packet ){
        icmp_header_ref header;

        header = icmp_prepare_packet( packet );
        if( ! header ){
                return icmp_release_and_return( packet, ENOMEM );
        }
        header->un.param.pointer = pointer;
        return icmp_send_packet( ICMP_PARAMETERPROB, code, packet, header, SERVICE_ICMP, 0, 0, 0 );
}

icmp_header_ref icmp_prepare_packet( packet_t packet ){
        icmp_header_ref header;
        size_t                  header_length;
        size_t                  total_length;

        total_length = packet_get_data_length( packet );
        if( total_length <= 0 ) return NULL;
        header_length = ip_client_header_length( packet );
        if( header_length <= 0 ) return NULL;
        // truncate if longer than 64 bits (without the IP header)
        if(( total_length > header_length + ICMP_KEEP_LENGTH )
        && ( packet_trim( packet, 0, total_length - header_length - ICMP_KEEP_LENGTH ) != EOK )){
                return NULL;
        }
        header = PACKET_PREFIX( packet, icmp_header_t );
        if( ! header ) return NULL;
        bzero( header, sizeof( * header ));
        return header;
}

int icmp_send_packet( icmp_type_t type, icmp_code_t code, packet_t packet, icmp_header_ref header, services_t error, ip_ttl_t ttl, ip_tos_t tos, int dont_fragment ){
        ERROR_DECLARE;

        // do not send an error if disabled
        if( error && ( ! icmp_globals.error_reporting )){
                return icmp_release_and_return( packet, EPERM );
        }
        header->type = type;
        header->code = code;
        header->checksum = 0;
        header->checksum = ICMP_CHECKSUM( header, packet_get_data_length( packet ));
        if( ERROR_OCCURRED( ip_client_prepare_packet( packet, IPPROTO_ICMP, ttl, tos, dont_fragment, 0 ))){
                return icmp_release_and_return( packet, ERROR_CODE );
        }
        return ip_send_msg( icmp_globals.ip_phone, -1, packet, SERVICE_ICMP, error );
}

int icmp_connect_module( services_t service, suseconds_t timeout ){
        icmp_echo_ref   echo_data;
        icmp_param_t    id;
        int                             index;

        echo_data = ( icmp_echo_ref ) malloc( sizeof( * echo_data ));
        if( ! echo_data ) return ENOMEM;
        // assign a new identifier
        fibril_rwlock_write_lock( & icmp_globals.lock );
        index = icmp_bind_free_id( echo_data );
        if( index < 0 ){
                free( echo_data );
                fibril_rwlock_write_unlock( & icmp_globals.lock );
                return index;
        }else{
                id = echo_data->identifier;
                fibril_rwlock_write_unlock( & icmp_globals.lock );
                // return the echo data identifier as the ICMP phone
                return id;
        }
}

int icmp_initialize( async_client_conn_t client_connection ){
        ERROR_DECLARE;

        measured_string_t       names[] = {{ str_dup("ICMP_ERROR_REPORTING"), 20 }, { str_dup("ICMP_ECHO_REPLYING"), 18 }};
        measured_string_ref     configuration;
        size_t                          count = sizeof( names ) / sizeof( measured_string_t );
        char *                          data;

        fibril_rwlock_initialize( & icmp_globals.lock );
        fibril_rwlock_write_lock( & icmp_globals.lock );
        icmp_replies_initialize( & icmp_globals.replies );
        icmp_echo_data_initialize( & icmp_globals.echo_data );
        icmp_globals.ip_phone = ip_bind_service( SERVICE_IP, IPPROTO_ICMP, SERVICE_ICMP, client_connection, icmp_received_msg );
        if( icmp_globals.ip_phone < 0 ){
                return icmp_globals.ip_phone;
        }
        ERROR_PROPAGATE( ip_packet_size_req( icmp_globals.ip_phone, -1, & icmp_globals.packet_dimension ));
        icmp_globals.packet_dimension.prefix += ICMP_HEADER_SIZE;
        icmp_globals.packet_dimension.content -= ICMP_HEADER_SIZE;
        // get configuration
        icmp_globals.error_reporting = NET_DEFAULT_ICMP_ERROR_REPORTING;
        icmp_globals.echo_replying = NET_DEFAULT_ICMP_ECHO_REPLYING;
        configuration = & names[ 0 ];
        ERROR_PROPAGATE( net_get_conf_req( icmp_globals.net_phone, & configuration, count, & data ));
        if( configuration ){
                if( configuration[ 0 ].value ){
                        icmp_globals.error_reporting = ( configuration[ 0 ].value[ 0 ] == 'y' );
                }
                if( configuration[ 1 ].value ){
                        icmp_globals.echo_replying = ( configuration[ 1 ].value[ 0 ] == 'y' );
                }
                net_free_settings( configuration, data );
        }
        fibril_rwlock_write_unlock( & icmp_globals.lock );
        return EOK;
}

int     icmp_received_msg( device_id_t device_id, packet_t packet, services_t receiver, services_t error ){
        ERROR_DECLARE;

        if( ERROR_OCCURRED( icmp_process_packet( packet, error ))){
                return icmp_release_and_return( packet, ERROR_CODE );
        }

        return EOK;
}

int icmp_process_packet( packet_t packet, services_t error ){
        ERROR_DECLARE;

        size_t                  length;
        uint8_t *               src;
        int                             addrlen;
        int                             result;
        void *                  data;
        icmp_header_ref header;
        icmp_type_t             type;
        icmp_code_t             code;

        if( error ){
                switch( error ){
                        case SERVICE_ICMP:
                                // process error
                                result = icmp_client_process_packet( packet, & type, & code, NULL, NULL );
                                if( result < 0 ) return result;
                                length = ( size_t ) result;
                                // remove the error header
                                ERROR_PROPAGATE( packet_trim( packet, length, 0 ));
                                break;
                        default:
                                return ENOTSUP;
                }
        }
        // get rid of the ip header
        length = ip_client_header_length( packet );
        ERROR_PROPAGATE( packet_trim( packet, length, 0 ));

        length = packet_get_data_length( packet );
        if( length <= 0 ) return EINVAL;
        if( length < ICMP_HEADER_SIZE) return EINVAL;
        data = packet_get_data( packet );
        if( ! data ) return EINVAL;
        // get icmp header
        header = ( icmp_header_ref ) data;
        // checksum
        if( header->checksum ){
                while( ICMP_CHECKSUM( header, length ) != IP_CHECKSUM_ZERO ){
                        // set the original message type on error notification
                        // type swap observed in Qemu
                        if( error ){
                                switch( header->type ){
                                        case ICMP_ECHOREPLY:
                                                header->type = ICMP_ECHO;
                                                continue;
                                }
                        }
                        return EINVAL;
                }
        }
        switch( header->type ){
                case ICMP_ECHOREPLY:
                        if( error ){
                                return icmp_process_echo_reply( packet, header, type, code );
                        }else{
                                return icmp_process_echo_reply( packet, header, ICMP_ECHO, 0 );
                        }
                case ICMP_ECHO:
                        if( error ){
                                return icmp_process_echo_reply( packet, header, type, code );
                        // do not send a reply if disabled
                        }else if( icmp_globals.echo_replying ){
                                addrlen = packet_get_addr( packet, & src, NULL );
                                if(( addrlen > 0 )
                                // set both addresses to the source one (avoids the source address deletion before setting the destination one)
                                && ( packet_set_addr( packet, src, src, ( size_t ) addrlen ) == EOK )){
                                        // send the reply
                                        icmp_send_packet( ICMP_ECHOREPLY, 0, packet, header, 0, 0, 0, 0 );
                                        return EOK;
                                }else{
                                        return EINVAL;
                                }
                        }else{
                                return EPERM;
                        }
                case ICMP_DEST_UNREACH:
                case ICMP_SOURCE_QUENCH:
                case ICMP_REDIRECT:
                case ICMP_ALTERNATE_ADDR:
                case ICMP_ROUTER_ADV:
                case ICMP_ROUTER_SOL:
                case ICMP_TIME_EXCEEDED:
                case ICMP_PARAMETERPROB:
                case ICMP_CONVERSION_ERROR:
                case ICMP_REDIRECT_MOBILE:
                case ICMP_SKIP:
                case ICMP_PHOTURIS:
                        ip_received_error_msg( icmp_globals.ip_phone, -1, packet, SERVICE_IP, SERVICE_ICMP );
                        return EOK;
                default:
                        return ENOTSUP;
        }
}

int icmp_process_echo_reply( packet_t packet, icmp_header_ref header, icmp_type_t type, icmp_code_t code ){
        int                             reply_key;
        icmp_reply_ref  reply;

        // compute the reply key
        reply_key = ICMP_GET_REPLY_KEY( header->un.echo.identifier, header->un.echo.sequence_number );
        pq_release( icmp_globals.net_phone, packet_get_id( packet ));
        // lock the globals
        fibril_rwlock_write_lock( & icmp_globals.lock );
        // find the pending reply
        reply = icmp_replies_find( & icmp_globals.replies, reply_key );
        if( reply ){
                // set the result
                reply->result = type;
                // notify the main fibril
                fibril_condvar_signal( & reply->condvar );
        }else{
                // unlock only if no reply
                fibril_rwlock_write_unlock( & icmp_globals.lock );
        }
        return EOK;
}

int icmp_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:
                        if( ! ERROR_OCCURRED( packet_translate( icmp_globals.net_phone, & packet, IPC_GET_PACKET( call )))){
                                ERROR_CODE = icmp_received_msg( IPC_GET_DEVICE( call ), packet, SERVICE_ICMP, IPC_GET_ERROR( call ));
                        }
                        return ERROR_CODE;
                case NET_ICMP_INIT:
                        return icmp_process_client_messages( callid, * call );
                default:
                        return icmp_process_message( call );
        }
        return ENOTSUP;
}

int icmp_process_client_messages( ipc_callid_t callid, ipc_call_t call ){
        ERROR_DECLARE;

        bool                                    keep_on_going = true;
//      fibril_rwlock_t                 lock;
        ipc_call_t                              answer;
        int                                             answer_count;
        size_t                                  length;
        struct sockaddr *               addr;
        ipc_callid_t                    data_callid;
        icmp_echo_ref                   echo_data;

        /*
         * Accept the connection
         *  - Answer the first NET_ICMP_INIT call.
         */
        ipc_answer_0( callid, EOK );

//      fibril_rwlock_initialize( & lock );

        echo_data = ( icmp_echo_ref ) malloc( sizeof( * echo_data ));
        if( ! echo_data ) return ENOMEM;
        // assign a new identifier
        fibril_rwlock_write_lock( & icmp_globals.lock );
        ERROR_CODE = icmp_bind_free_id( echo_data );
        fibril_rwlock_write_unlock( & icmp_globals.lock );
        if( ERROR_CODE < 0 ){
                free( echo_data );
                return ERROR_CODE;
        }

        while( keep_on_going ){
                refresh_answer( & answer, & answer_count );

                callid = async_get_call( & call );

                switch( IPC_GET_METHOD( call )){
                        case IPC_M_PHONE_HUNGUP:
                                keep_on_going = false;
                                ERROR_CODE = EOK;
                                break;
                        case NET_ICMP_ECHO:
//                              fibril_rwlock_write_lock( & lock );
                                if( ! async_data_write_receive( & data_callid, & length )){
                                        ERROR_CODE = EINVAL;
                                }else{
                                        addr = malloc( length );
                                        if( ! addr ){
                                                ERROR_CODE = ENOMEM;
                                        }else{
                                                if( ! ERROR_OCCURRED( async_data_write_finalize( data_callid, addr, length ))){
                                                        fibril_rwlock_write_lock( & icmp_globals.lock );
                                                        ERROR_CODE = icmp_echo( echo_data->identifier, echo_data->sequence_number, ICMP_GET_SIZE( call ), ICMP_GET_TIMEOUT( call ), ICMP_GET_TTL( call ), ICMP_GET_TOS( call ), ICMP_GET_DONT_FRAGMENT( call ), addr, ( socklen_t ) length );
                                                        fibril_rwlock_write_unlock( & icmp_globals.lock );
                                                        free( addr );
                                                        if( echo_data->sequence_number < MAX_UINT16 ){
                                                                ++ echo_data->sequence_number;
                                                        }else{
                                                                echo_data->sequence_number = 0;
                                                        }
                                                }
                                        }
                                }
//                              fibril_rwlock_write_unlock( & lock );
                                break;
                        default:
                                ERROR_CODE = icmp_process_message( & call );
                }

                answer_call( callid, ERROR_CODE, & answer, answer_count );
        }

        // release the identifier
        fibril_rwlock_write_lock( & icmp_globals.lock );
        icmp_echo_data_exclude( & icmp_globals.echo_data, echo_data->identifier );
        fibril_rwlock_write_unlock( & icmp_globals.lock );
        return EOK;
}

int icmp_process_message( ipc_call_t * call ){
        ERROR_DECLARE;

        packet_t        packet;

        switch( IPC_GET_METHOD( * call )){
                case NET_ICMP_DEST_UNREACH:
                        if( ! ERROR_OCCURRED( packet_translate( icmp_globals.net_phone, & packet, IPC_GET_PACKET( call )))){
                                ERROR_CODE = icmp_destination_unreachable_msg( 0, ICMP_GET_CODE( call ), ICMP_GET_MTU( call ), packet );
                        }
                        return ERROR_CODE;
                case NET_ICMP_SOURCE_QUENCH:
                        if( ! ERROR_OCCURRED( packet_translate( icmp_globals.net_phone, & packet, IPC_GET_PACKET( call )))){
                                ERROR_CODE = icmp_source_quench_msg( 0, packet );
                        }
                        return ERROR_CODE;
                case NET_ICMP_TIME_EXCEEDED:
                        if( ! ERROR_OCCURRED( packet_translate( icmp_globals.net_phone, & packet, IPC_GET_PACKET( call )))){
                                ERROR_CODE = icmp_time_exceeded_msg( 0, ICMP_GET_CODE( call ), packet );
                        }
                        return ERROR_CODE;
                case NET_ICMP_PARAMETERPROB:
                        if( ! ERROR_OCCURRED( packet_translate( icmp_globals.net_phone, & packet, IPC_GET_PACKET( call )))){
                                ERROR_CODE = icmp_parameter_problem_msg( 0, ICMP_GET_CODE( call ), ICMP_GET_POINTER( call ), packet );
                        }
                        return ERROR_CODE;
                default:
                        return ENOTSUP;
        }
}

int     icmp_release_and_return( packet_t packet, int result ){
        pq_release( icmp_globals.net_phone, packet_get_id( packet ));
        return result;
}

int icmp_bind_free_id( icmp_echo_ref echo_data ){
        icmp_param_t    index;

        if( ! echo_data ) return EBADMEM;
        // from the last used one
        index = icmp_globals.last_used_id;
        do{
                ++ index;
                // til the range end
                if( index >= ICMP_FREE_IDS_END ){
                        // start from the range beginning
                        index = ICMP_FREE_IDS_START - 1;
                        do{
                                ++ index;
                                // til the last used one
                                if( index >= icmp_globals.last_used_id ){
                                        // none found
                                        return ENOTCONN;
                                }
                        }while( icmp_echo_data_find( & icmp_globals.echo_data, index ) != NULL );
                        // found, break immediately
                        break;
                }
        }while( icmp_echo_data_find( & icmp_globals.echo_data, index ) != NULL );
        echo_data->identifier = index;
        echo_data->sequence_number = 0;
        return icmp_echo_data_add( & icmp_globals.echo_data, index, echo_data );
}

/** @}
 */