strongSwan

/*

 * Copyright (C) 2005-2009 Martin Willi

 * Copyright (C) 2005 Jan Hutter

 * Hochschule fuer Technik Rapperswil

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation; either version 2 of the License, or (at your

 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * for more details.

 */

#include <stdlib.h>

#include <string.h>

#include <arpa/inet.h>

#include <stdio.h>

#include "generator.h"

#include <library.h>

#include <daemon.h>

#include <utils/linked_list.h>

#include <encoding/payloads/payload.h>

#include <encoding/payloads/proposal_substructure.h>

#include <encoding/payloads/transform_substructure.h>

#include <encoding/payloads/sa_payload.h>

#include <encoding/payloads/ke_payload.h>

#include <encoding/payloads/notify_payload.h>

#include <encoding/payloads/nonce_payload.h>

#include <encoding/payloads/id_payload.h>

#include <encoding/payloads/auth_payload.h>

#include <encoding/payloads/cert_payload.h>

#include <encoding/payloads/certreq_payload.h>

#include <encoding/payloads/ts_payload.h>

#include <encoding/payloads/delete_payload.h>

#include <encoding/payloads/vendor_id_payload.h>

#include <encoding/payloads/cp_payload.h>

#include <encoding/payloads/configuration_attribute.h>

#include <encoding/payloads/eap_payload.h>

typedef struct private_generator_t private_generator_t;

/**

 * Private part of a generator_t object.

 */

struct private_generator_t {

    /**

     * Public part of a generator_t object.

     */

     generator_t public;

    /**

     * Buffer used to generate the data into.

     */

    u_int8_t *buffer;

    /**

     * Current write position in buffer (one byte aligned).

     */

    u_int8_t *out_position;

    /**

     * Position of last byte in buffer.

     */

    u_int8_t *roof_position;

    /**

     * Current bit writing to in current byte (between 0 and 7).

     */

    u_int8_t current_bit;

    /**

     * Associated data struct to read informations from.

     */

    void *data_struct;

    /*

     * Last payload length position offset in the buffer.

     */

    u_int32_t last_payload_length_position_offset;

    /**

     * Offset of the header length field in the buffer.

     */

    u_int32_t header_length_position_offset;

    /**

     * Last SPI size.

     */

    u_int8_t last_spi_size;

    /**

     * Attribute format of the last generated transform attribute.

     *

     * Used to check if a variable value field is used or not for

     * the transform attribute value.

     */

    bool attribute_format;

    /**

     * Depending on the value of attribute_format this field is used

     * to hold the length of the transform attribute in bytes.

     */

    u_int16_t attribute_length;

};

/**

 * Get size of current buffer in bytes.

 */

static int get_size(private_generator_t *this)

{

    return this->roof_position - this->buffer;

}

/**

 * Get free space of current buffer in bytes.

 */

static int get_space(private_generator_t *this)

{

    return this->roof_position - this->out_position;

}

/**

 * Get length of data in buffer (in bytes).

 */

static int get_length(private_generator_t *this)

{

    return this->out_position - this->buffer;

}

/**

 * Get current offset in buffer (in bytes).

 */

static u_int32_t get_offset(private_generator_t *this)

{

    return this->out_position - this->buffer;

}

/**

 * Makes sure enough space is available in buffer to store amount of bits.

 */

static void make_space_available(private_generator_t *this, int bits)

{

    while ((get_space(this) * 8 - this->current_bit) < bits)

    {

        int old_buffer_size, new_buffer_size, out_position_offset;

        old_buffer_size = get_size(this);

        new_buffer_size = old_buffer_size + GENERATOR_DATA_BUFFER_INCREASE_VALUE;

        out_position_offset = this->out_position - this->buffer;

        DBG2(DBG_ENC, "increasing gen buffer from %d to %d byte",

             old_buffer_size, new_buffer_size);

        this->buffer = realloc(this->buffer,new_buffer_size);

        this->out_position = (this->buffer + out_position_offset);

        this->roof_position = (this->buffer + new_buffer_size);

    }

}

/**

 * Writes a specific amount of byte into the buffer.

 */

static void write_bytes_to_buffer(private_generator_t *this, void *bytes,

                                  int number_of_bytes)

{

    int i;

    u_int8_t *read_position = (u_int8_t *)bytes;

    make_space_available(this, number_of_bytes * 8);

    for (i = 0; i < number_of_bytes; i++)

    {

        *(this->out_position) = *(read_position);

        read_position++;

        this->out_position++;

    }

}

/**

 * Writes a specific amount of byte into the buffer at a specific offset.

 */

static void write_bytes_to_buffer_at_offset(private_generator_t *this,

                        void *bytes, int number_of_bytes, u_int32_t offset)

{

    int i;

    u_int8_t *read_position = (u_int8_t *)bytes;

    u_int8_t *write_position;

    u_int32_t free_space_after_offset = get_size(this) - offset;

    /* check first if enough space for new data is available */

    if (number_of_bytes > free_space_after_offset)

    {

        make_space_available(this,

                             (number_of_bytes - free_space_after_offset) * 8);

    }

    write_position = this->buffer + offset;

    for (i = 0; i < number_of_bytes; i++)

    {

        *write_position = *read_position;

        read_position++;

        write_position++;

    }

}

/**

 * Generates a U_INT-Field type and writes it to buffer.

 */

static void generate_u_int_type(private_generator_t *this,

                                encoding_type_t int_type,u_int32_t offset)

{

    int number_of_bits = 0;

    /* find out number of bits of each U_INT type to check for enough space */

    switch (int_type)

    {

        case U_INT_4:

            number_of_bits = 4;

            break;

        case TS_TYPE:

        case U_INT_8:

            number_of_bits = 8;

            break;

        case U_INT_16:

        case CONFIGURATION_ATTRIBUTE_LENGTH:

            number_of_bits = 16;

            break;

        case U_INT_32:

            number_of_bits = 32;

            break;

        case ATTRIBUTE_TYPE:

            number_of_bits = 15;

            break;

        case IKE_SPI:

            number_of_bits = 64;

            break;

        default:

            DBG1(DBG_ENC, "U_INT Type %N is not supported",

                 encoding_type_names, int_type);

            return;

    }

    if ((number_of_bits % 8) == 0 && this->current_bit != 0)

    {

        DBG1(DBG_ENC, "U_INT Type %N is not 8 Bit aligned",

             encoding_type_names, int_type);

        return;

    }

    make_space_available(this, number_of_bits);

    switch (int_type)

    {

        case U_INT_4:

        {

            u_int8_t high, low;

            if (this->current_bit == 0)

            {

                /* high of current byte in buffer has to be set to the new value*/

                high = *((u_int8_t *)(this->data_struct + offset)) << 4;

                /* low in buffer is not changed */

                low = *(this->out_position) & 0x0F;

                /* high is set, low_val is not changed */

                *(this->out_position) = high | low;

                DBG3(DBG_ENC, "   => %d", *(this->out_position));

                /* write position is not changed, just bit position is moved */

                this->current_bit = 4;

            }

            else if (this->current_bit == 4)

            {

                /* high in buffer is not changed */

                high = *(this->out_position) & 0xF0;

                /* low of current byte in buffer has to be set to the new value*/

                low = *((u_int8_t *)(this->data_struct + offset)) & 0x0F;

                *(this->out_position) = high | low;

                DBG3(DBG_ENC, "   => %d", *(this->out_position));

                this->out_position++;

                this->current_bit = 0;

            }

            else

            {

                DBG1(DBG_ENC, "U_INT_4 Type is not 4 Bit aligned");

                /* 4 Bit integers must have a 4 bit alignment */

                return;

            }

            break;

        }

        case TS_TYPE:

        case U_INT_8:

        {

            /* 8 bit values are written as they are */

            *this->out_position = *((u_int8_t *)(this->data_struct + offset));

            DBG3(DBG_ENC, "   => %d", *(this->out_position));

            this->out_position++;

            break;

        }

        case ATTRIBUTE_TYPE:

        {

            u_int8_t attribute_format_flag;

            u_int16_t val;

            /* attribute type must not change first bit of current byte */

            if (this->current_bit != 1)

            {

                DBG1(DBG_ENC, "ATTRIBUTE FORMAT flag is not set");

                return;

            }

            attribute_format_flag = *(this->out_position) & 0x80;

            /* get attribute type value as 16 bit integer*/

            val = *((u_int16_t*)(this->data_struct + offset));

            /* unset most significant bit */

            val &= 0x7FFF;

            if (attribute_format_flag)

            {

                val |= 0x8000;

            }

            val = htons(val);

            DBG3(DBG_ENC, "   => %d", val);

            /* write bytes to buffer (set bit is overwritten) */

            write_bytes_to_buffer(this, &val, sizeof(u_int16_t));

            this->current_bit = 0;

            break;

        }

        case U_INT_16:

        case CONFIGURATION_ATTRIBUTE_LENGTH:

        {

            u_int16_t val = htons(*((u_int16_t*)(this->data_struct + offset)));

            DBG3(DBG_ENC, "   => %b", &val, sizeof(u_int16_t));

            write_bytes_to_buffer(this, &val, sizeof(u_int16_t));

            break;

        }

        case U_INT_32:

        {

            u_int32_t val = htonl(*((u_int32_t*)(this->data_struct + offset)));

            DBG3(DBG_ENC, "   => %b", &val, sizeof(u_int32_t));

            write_bytes_to_buffer(this, &val, sizeof(u_int32_t));

            break;

        }

        case IKE_SPI:

        {

            /* 64 bit are written as-is, no host order conversion */

            write_bytes_to_buffer(this, this->data_struct + offset,

                                  sizeof(u_int64_t));

            DBG3(DBG_ENC, "   => %b", this->data_struct + offset,

                 sizeof(u_int64_t));

            break;

        }

        default:

        {

            DBG1(DBG_ENC, "U_INT Type %N is not supported",

                 encoding_type_names, int_type);

            return;

        }

    }

}

/**

 * Generate a reserved bit or byte

 */

static void generate_reserved_field(private_generator_t *this, int bits)

{

    /* only one bit or 8 bit fields are supported */

    if (bits != 1 && bits != 8)

    {

        DBG1(DBG_ENC, "reserved field of %d bits cannot be generated", bits);

        return ;

    }

    make_space_available(this, bits);

    if (bits == 1)

    {

        u_int8_t reserved_bit = ~(1 << (7 - this->current_bit));

        *(this->out_position) = *(this->out_position) & reserved_bit;

        if (this->current_bit == 0)

        {

            /* memory must be zero */

            *(this->out_position) = 0x00;

        }

        this->current_bit++;

        if (this->current_bit >= 8)

        {

            this->current_bit = this->current_bit % 8;

            this->out_position++;

        }

    }

    else

    {

        if (this->current_bit > 0)

        {

            DBG1(DBG_ENC, "reserved field cannot be written cause "

                 "alignement of current bit is %d", this->current_bit);

            return;

        }

        *(this->out_position) = 0x00;

        this->out_position++;

    }

}

/**

 * Generate a FLAG filed

 */

static void generate_flag(private_generator_t *this, u_int32_t offset)

{

    u_int8_t flag_value;

    u_int8_t flag;

    flag_value = (*((bool *) (this->data_struct + offset))) ? 1 : 0;

    /* get flag position */

    flag = (flag_value << (7 - this->current_bit));

    /* make sure one bit is available in buffer */

    make_space_available(this, 1);

    if (this->current_bit == 0)

    {

        /* memory must be zero */

        *(this->out_position) = 0x00;

    }

    *(this->out_position) = *(this->out_position) | flag;

    DBG3(DBG_ENC, "   => %d", *this->out_position);

    this->current_bit++;

    if (this->current_bit >= 8)

    {

        this->current_bit = this->current_bit % 8;

        this->out_position++;

    }

}

/**

 * Generates a bytestream from a chunk_t.

 */

static void generate_from_chunk(private_generator_t *this, u_int32_t offset)

{

    chunk_t *value;

    if (this->current_bit != 0)

    {

        DBG1(DBG_ENC, "can not generate a chunk at Bitpos %d", this->current_bit);

        return ;

    }

    value = (chunk_t *)(this->data_struct + offset);

    DBG3(DBG_ENC, "   => %B", value);

    write_bytes_to_buffer(this, value->ptr, value->len);

}

/**

 * Implementation of private_generator_t.write_to_chunk.

 */

static void write_to_chunk(private_generator_t *this,chunk_t *data)

{

    int data_length = get_length(this);

    u_int32_t header_length_field = data_length;

    /* write length into header length field */

    if (this->header_length_position_offset > 0)

    {

        u_int32_t val = htonl(header_length_field);

        write_bytes_to_buffer_at_offset(this, &val, sizeof(u_int32_t),

                                        this->header_length_position_offset);

    }

    if (this->current_bit > 0)

    {

        data_length++;

    }

    *data = chunk_alloc(data_length);

    memcpy(data->ptr, this->buffer, data_length);

    DBG3(DBG_ENC, "generated data of this generator %B", data);

}

/**

 * Implementation of private_generator_t.generate_payload.

 */

static void generate_payload (private_generator_t *this,payload_t *payload)

{

    int i, offset_start;

    size_t rule_count;

    encoding_rule_t *rules;

    payload_type_t payload_type;

    this->data_struct = payload;

    payload_type = payload->get_type(payload);

    /* spi size has to get reseted */

    this->last_spi_size = 0;

    offset_start = this->out_position - this->buffer;

    DBG2(DBG_ENC, "generating payload of type %N",

         payload_type_names, payload_type);

    /* each payload has its own encoding rules */

    payload->get_encoding_rules(payload, &rules, &rule_count);

    for (i = 0; i < rule_count;i++)

    {

        DBG2(DBG_ENC, "  generating rule %d %N",

             i, encoding_type_names, rules[i].type);

        switch (rules[i].type)

        {

            case U_INT_4:

            case U_INT_8:

            case U_INT_16:

            case U_INT_32:

            case IKE_SPI:

            case TS_TYPE:

            case ATTRIBUTE_TYPE:

            case CONFIGURATION_ATTRIBUTE_LENGTH:

            {

                generate_u_int_type(this, rules[i].type, rules[i].offset);

                break;

            }

            case RESERVED_BIT:

            {

                generate_reserved_field(this, 1);

                break;

            }

            case RESERVED_BYTE:

            {

                generate_reserved_field(this, 8);

                break;

            }

            case FLAG:

            {

                generate_flag(this, rules[i].offset);

                break;

            }

            case PAYLOAD_LENGTH:

            {

                this->last_payload_length_position_offset = get_offset(this);

                generate_u_int_type(this, U_INT_16,rules[i].offset);

                break;

            }

            case HEADER_LENGTH:

            {

                this->header_length_position_offset = get_offset(this);

                generate_u_int_type(this ,U_INT_32, rules[i].offset);

                break;

            }

            case SPI_SIZE:

                generate_u_int_type(this, U_INT_8, rules[i].offset);

                this->last_spi_size = *((u_int8_t *)(this->data_struct +

                                                     rules[i].offset));

                break;

            case ADDRESS:

            {

                generate_from_chunk(this, rules[i].offset);

                break;

            }

            case SPI:

            {

                generate_from_chunk(this, rules[i].offset);

                break;

            }

            case KEY_EXCHANGE_DATA:

            case NOTIFICATION_DATA:

            case NONCE_DATA:

            case ID_DATA:

            case AUTH_DATA:

            case CERT_DATA:

            case CERTREQ_DATA:

            case SPIS:

            case CONFIGURATION_ATTRIBUTE_VALUE:

            case VID_DATA:

            case EAP_DATA:

            {

                u_int32_t payload_length_position_offset;

                u_int16_t length_of_payload;

                u_int16_t header_length = 0;

                u_int16_t length_in_network_order;

                switch(rules[i].type)

                {

                    case KEY_EXCHANGE_DATA:

                        header_length = KE_PAYLOAD_HEADER_LENGTH;

                        break;

                    case NOTIFICATION_DATA:

                        header_length = NOTIFY_PAYLOAD_HEADER_LENGTH +

                                                        this->last_spi_size;

                        break;

                    case NONCE_DATA:

                        header_length = NONCE_PAYLOAD_HEADER_LENGTH;

                        break;

                    case ID_DATA:

                        header_length = ID_PAYLOAD_HEADER_LENGTH;

                        break;

                    case AUTH_DATA:

                        header_length = AUTH_PAYLOAD_HEADER_LENGTH;

                        break;

                    case CERT_DATA:

                        header_length = CERT_PAYLOAD_HEADER_LENGTH;

                        break;

                    case CERTREQ_DATA:

                        header_length = CERTREQ_PAYLOAD_HEADER_LENGTH;

                        break;

                    case SPIS:

                        header_length = DELETE_PAYLOAD_HEADER_LENGTH;

                        break;

                    case VID_DATA:

                        header_length = VENDOR_ID_PAYLOAD_HEADER_LENGTH;

                        break;

                    case CONFIGURATION_ATTRIBUTE_VALUE:

                        header_length = CONFIGURATION_ATTRIBUTE_HEADER_LENGTH;

                        break;

                    case EAP_DATA:

                        header_length = EAP_PAYLOAD_HEADER_LENGTH;

                        break;

                    default:

                        break;

                }

                generate_from_chunk(this, rules[i].offset);

                payload_length_position_offset =

                                    this->last_payload_length_position_offset;

                length_of_payload = header_length +

                        ((chunk_t *)(this->data_struct + rules[i].offset))->len;

                length_in_network_order = htons(length_of_payload);

                write_bytes_to_buffer_at_offset(this, &length_in_network_order,

                            sizeof(u_int16_t), payload_length_position_offset);

                break;

            }

            case PROPOSALS:

            {

                u_int32_t payload_length_position_offset =

                                    this->last_payload_length_position_offset;

                /* Length of SA_PAYLOAD is calculated */

                u_int16_t length_of_sa_payload = SA_PAYLOAD_HEADER_LENGTH;

                u_int16_t int16_val;

                linked_list_t *proposals = *((linked_list_t **)

                                        (this->data_struct + rules[i].offset));

                iterator_t *iterator;

                payload_t *current_proposal;

                iterator = proposals->create_iterator(proposals,TRUE);

                while (iterator->iterate(iterator, (void**)&current_proposal))

                {

                    u_int32_t before_generate_position_offset;

                    u_int32_t after_generate_position_offset;

                    before_generate_position_offset = get_offset(this);

                    generate_payload(this, current_proposal);

                    after_generate_position_offset = get_offset(this);

                    length_of_sa_payload += (after_generate_position_offset -

                                             before_generate_position_offset);

                }

                iterator->destroy(iterator);

                int16_val = htons(length_of_sa_payload);

                write_bytes_to_buffer_at_offset(this, &int16_val,

                            sizeof(u_int16_t),payload_length_position_offset);

                break;

            }

            case TRANSFORMS:

            {

                u_int32_t payload_length_position_offset =

                                    this->last_payload_length_position_offset;

                u_int16_t length_of_proposal =

                    PROPOSAL_SUBSTRUCTURE_HEADER_LENGTH + this->last_spi_size;

                u_int16_t int16_val;

                linked_list_t *transforms = *((linked_list_t **)

                                        (this->data_struct + rules[i].offset));

                iterator_t *iterator;

                payload_t *current_transform;

                iterator = transforms->create_iterator(transforms,TRUE);

                while (iterator->iterate(iterator, (void**)&current_transform))

                {

                    u_int32_t before_generate_position_offset;

                    u_int32_t after_generate_position_offset;

                    before_generate_position_offset = get_offset(this);

                    generate_payload(this, current_transform);

                    after_generate_position_offset = get_offset(this);

                    length_of_proposal += (after_generate_position_offset -

                                           before_generate_position_offset);

                }

                iterator->destroy(iterator);

                int16_val = htons(length_of_proposal);

                write_bytes_to_buffer_at_offset(this, &int16_val,

                            sizeof(u_int16_t), payload_length_position_offset);

                break;

            }

            case TRANSFORM_ATTRIBUTES:

            {

                u_int32_t transform_length_position_offset =

                                    this->last_payload_length_position_offset;

                u_int16_t length_of_transform =

                                    TRANSFORM_SUBSTRUCTURE_HEADER_LENGTH;

                u_int16_t int16_val;

                linked_list_t *transform_attributes =*((linked_list_t **)

                                    (this->data_struct + rules[i].offset));

                iterator_t *iterator;

                payload_t *current_attribute;

                iterator = transform_attributes->create_iterator(

                                                    transform_attributes, TRUE);

                while (iterator->iterate(iterator, (void**)&current_attribute))

                {

                    u_int32_t before_generate_position_offset;

                    u_int32_t after_generate_position_offset;

                    before_generate_position_offset = get_offset(this);

                    generate_payload(this, current_attribute);

                    after_generate_position_offset = get_offset(this);

                    length_of_transform += (after_generate_position_offset -

                                            before_generate_position_offset);

                }

                iterator->destroy(iterator);

                int16_val = htons(length_of_transform);

                write_bytes_to_buffer_at_offset(this, &int16_val,

                            sizeof(u_int16_t),transform_length_position_offset);

                break;

            }

            case CONFIGURATION_ATTRIBUTES:

            {

                u_int32_t configurations_length_position_offset =

                                    this->last_payload_length_position_offset;

                u_int16_t length_of_configurations = CP_PAYLOAD_HEADER_LENGTH;

                u_int16_t int16_val;

                linked_list_t *configuration_attributes = *((linked_list_t **)

                                        (this->data_struct + rules[i].offset));

                iterator_t *iterator;

                payload_t *current_attribute;

                iterator = configuration_attributes->create_iterator(

                                                configuration_attributes,TRUE);

                while (iterator->iterate(iterator, (void**)&current_attribute))

                {

                    u_int32_t before_generate_position_offset;

                    u_int32_t after_generate_position_offset;

                    before_generate_position_offset = get_offset(this);

                    generate_payload(this, current_attribute);

                    after_generate_position_offset = get_offset(this);

                    length_of_configurations += after_generate_position_offset -

                                            before_generate_position_offset;

                }

                iterator->destroy(iterator);

                int16_val = htons(length_of_configurations);

                write_bytes_to_buffer_at_offset(this, &int16_val,

                     sizeof(u_int16_t),configurations_length_position_offset);

                break;

            }

            case ATTRIBUTE_FORMAT:

            {

                generate_flag(this, rules[i].offset);

                /* Attribute format is a flag which is stored in context*/

                this->attribute_format =

                            *((bool *)(this->data_struct + rules[i].offset));

                break;

            }

            case ATTRIBUTE_LENGTH_OR_VALUE:

            {

                if (this->attribute_format == FALSE)

                {

                    generate_u_int_type(this, U_INT_16, rules[i].offset);

                    /* this field hold the length of the attribute */

                    this->attribute_length =

                        *((u_int16_t *)(this->data_struct + rules[i].offset));

                }

                else

                {

                    generate_u_int_type(this, U_INT_16, rules[i].offset);

                }

                break;

            }

            case ATTRIBUTE_VALUE:

            {

                if (this->attribute_format == FALSE)

                {

                    DBG2(DBG_ENC, "attribute value has not fixed size");

                    /* the attribute value is generated */

                    generate_from_chunk(this, rules[i].offset);

                }

                break;

            }

            case TRAFFIC_SELECTORS:

            {

                u_int32_t payload_length_position_offset =

                                    this->last_payload_length_position_offset;

                u_int16_t length_of_ts_payload = TS_PAYLOAD_HEADER_LENGTH;

                u_int16_t int16_val;

                linked_list_t *traffic_selectors = *((linked_list_t **)

                                        (this->data_struct + rules[i].offset));

                iterator_t *iterator;

                payload_t *current_tss;

                iterator = traffic_selectors->create_iterator(

                                                    traffic_selectors,TRUE);

                while (iterator->iterate(iterator, (void **)&current_tss))

                {

                    u_int32_t before_generate_position_offset;

                    u_int32_t after_generate_position_offset;

                    before_generate_position_offset = get_offset(this);

                    generate_payload(this, current_tss);

                    after_generate_position_offset = get_offset(this);

                    length_of_ts_payload += (after_generate_position_offset -

                                             before_generate_position_offset);

                }

                iterator->destroy(iterator);

                int16_val = htons(length_of_ts_payload);

                write_bytes_to_buffer_at_offset(this, &int16_val,

                            sizeof(u_int16_t),payload_length_position_offset);

                break;

            }

            case ENCRYPTED_DATA:

            {

                generate_from_chunk(this, rules[i].offset);

                break;

            }

            default:

                DBG1(DBG_ENC, "field type %N is not supported",

                     encoding_type_names, rules[i].type);

                return;

        }

    }

    DBG2(DBG_ENC, "generating %N payload finished",

         payload_type_names, payload_type);

    DBG3(DBG_ENC, "generated data for this payload %b",

         this->buffer + offset_start,

         this->out_position - this->buffer - offset_start);

}

/**

 * Implementation of generator_t.destroy.

 */

static status_t destroy(private_generator_t *this)

{

    free(this->buffer);

    free(this);

    return SUCCESS;

}

/*

 * Described in header

 */

generator_t *generator_create()

{

    private_generator_t *this;

    this = malloc_thing(private_generator_t);

    /* initiate public functions */

    this->public.generate_payload = (void(*)(generator_t*, payload_t *))generate_payload;

    this->public.destroy = (void(*)(generator_t*)) destroy;

    this->public.write_to_chunk = (void (*) (generator_t *,chunk_t *))write_to_chunk;

    /* allocate memory for buffer */

    this->buffer = malloc(GENERATOR_DATA_BUFFER_SIZE);

    /* initiate private variables */

    this->out_position = this->buffer;

    this->roof_position = this->buffer + GENERATOR_DATA_BUFFER_SIZE;

    this->data_struct = NULL;

    this->current_bit = 0;

    this->last_payload_length_position_offset = 0;

    this->header_length_position_offset = 0;

    this->attribute_format = FALSE;

    this->attribute_length = 0;

    return &(this->public);

}