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strongswan/src/charon/encoding/generator.c

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/*
* Copyright (C) 2005-2006 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.
*
* $Id$
*/
#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).
*/
size_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 size_t get_current_buffer_size(private_generator_t *this)
{
return this->roof_position - this->buffer;
}
/**
* Get free space of current buffer in bytes.
*/
static size_t get_current_buffer_space(private_generator_t *this)
{
return this->roof_position - this->out_position;
}
/**
* Get length of data in buffer (in bytes).
*/
static size_t get_current_data_length(private_generator_t *this)
{
return this->out_position - this->buffer;
}
/**
* Get current offset in buffer (in bytes).
*/
static u_int32_t get_current_buffer_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, size_t bits)
{
while ((get_current_buffer_space(this) * 8 - this->current_bit) < bits)
{
/* must increase buffer */
size_t old_buffer_size = get_current_buffer_size(this);
size_t new_buffer_size = old_buffer_size + GENERATOR_DATA_BUFFER_INCREASE_VALUE;
size_t out_position_offset = ((this->out_position) - (this->buffer));
DBG2(DBG_ENC, "increased gen buffer from %d to %d byte",
old_buffer_size, new_buffer_size);
/* Reallocate space for new buffer */
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,
size_t 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, size_t 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_current_buffer_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.
*
* @param this private_generator_t object
* @param int_type type of U_INT field (U_INT_4, U_INT_8, etc.)
* ATTRIBUTE_TYPE is also generated in this function
* @param offset offset of value in data struct
* @param generator_contexts generator_contexts_t object where the context is written or read from
*/
static void generate_u_int_type(private_generator_t *this,
encoding_type_t int_type,u_int32_t offset)
{
size_t number_of_bits = 0;
/* find out number of bits of each U_INT type to check for enough space
in buffer */
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 U_INT_64:
number_of_bits = 64;
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;
}
/* U_INT Types of multiple then 8 bits must be aligned */
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);
/* current bit has to be zero for values multiple of 8 bits */
return;
}
/* make sure enough space is available in buffer */
make_space_available(this, number_of_bits);
/* now handle each u int type differently */
switch (int_type)
{
case U_INT_4:
{
if (this->current_bit == 0)
{
/* highval of current byte in buffer has to be set to the new value*/
u_int8_t high_val = *((u_int8_t *)(this->data_struct + offset)) << 4;
/* lowval in buffer is not changed */
u_int8_t low_val = *(this->out_position) & 0x0F;
/* highval is set, low_val is not changed */
*(this->out_position) = high_val | low_val;
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)
{
/* highval in buffer is not changed */
u_int high_val = *(this->out_position) & 0xF0;
/* lowval of current byte in buffer has to be set to the new value*/
u_int low_val = *((u_int8_t *)(this->data_struct + offset)) & 0x0F;
*(this->out_position) = high_val | low_val;
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:
{
/* attribute type must not change first bit uf current byte ! */
if (this->current_bit != 1)
{
DBG1(DBG_ENC, "ATTRIBUTE FORMAT flag is not set");
/* first bit has to be set! */
return;
}
/* get value of attribute format flag */
u_int8_t attribute_format_flag = *(this->out_position) & 0x80;
/* get attribute type value as 16 bit integer*/
u_int16_t int16_val = *((u_int16_t*)(this->data_struct + offset));
/* unset most significant bit */
int16_val &= 0x7FFF;
if (attribute_format_flag)
{
int16_val |= 0x8000;
}
int16_val = htons(int16_val);
DBG3(DBG_ENC, " => %d", int16_val);
/* write bytes to buffer (set bit is overwritten)*/
write_bytes_to_buffer(this, &int16_val, sizeof(u_int16_t));
this->current_bit = 0;
break;
}
case U_INT_16:
case CONFIGURATION_ATTRIBUTE_LENGTH:
{
u_int16_t int16_val = htons(*((u_int16_t*)(this->data_struct + offset)));
DBG3(DBG_ENC, " => %b", (void*)&int16_val, sizeof(int16_val));
write_bytes_to_buffer(this, &int16_val, sizeof(u_int16_t));
break;
}
case U_INT_32:
{
u_int32_t int32_val = htonl(*((u_int32_t*)(this->data_struct + offset)));
DBG3(DBG_ENC, " => %b", (void*)&int32_val, sizeof(int32_val));
write_bytes_to_buffer(this, &int32_val, sizeof(u_int32_t));
break;
}
case U_INT_64:
{
/* 64 bit integers are written as two 32 bit integers */
u_int32_t int32_val_low = htonl(*((u_int32_t*)(this->data_struct + offset)));
u_int32_t int32_val_high = htonl(*((u_int32_t*)(this->data_struct + offset) + 1));
DBG3(DBG_ENC, " => %b %b",
(void*)&int32_val_low, sizeof(int32_val_low),
(void*)&int32_val_high, sizeof(int32_val_high));
/* TODO add support for big endian machines */
write_bytes_to_buffer(this, &int32_val_high, sizeof(u_int32_t));
write_bytes_to_buffer(this, &int32_val_low, sizeof(u_int32_t));
break;
}
case IKE_SPI:
{
/* 64 bit are written as they come :-) */
write_bytes_to_buffer(this, this->data_struct + offset, sizeof(u_int64_t));
DBG3(DBG_ENC, " => %b", (void*)(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 sure enough space is available in buffer */
make_space_available(this, bits);
if (bits == 1)
{
/* one bit processing */
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
{
/* one byte processing*/
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)
{
/* value of current flag */
u_int8_t flag_value;
/* position of flag in current byte */
u_int8_t flag;
/* if the value in the data_struct is TRUE, flag_value is set to 1, 0 otherwise */
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)
{
if (this->current_bit != 0)
{
DBG1(DBG_ENC, "can not generate a chunk at Bitpos %d", this->current_bit);
return ;
}
/* position in buffer */
chunk_t *attribute_value = (chunk_t *)(this->data_struct + offset);
DBG3(DBG_ENC, " => %B", attribute_value);
/* use write_bytes_to_buffer function to do the job */
write_bytes_to_buffer(this, attribute_value->ptr, attribute_value->len);
}
/**
* Implementation of private_generator_t.write_to_chunk.
*/
static void write_to_chunk (private_generator_t *this,chunk_t *data)
{
size_t data_length = get_current_data_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 int32_val = htonl(header_length_field);
write_bytes_to_buffer_at_offset(this, &int32_val, sizeof(u_int32_t),
this->header_length_position_offset);
}
if (this->current_bit > 0)
data_length++;
data->ptr = malloc(data_length);
memcpy(data->ptr,this->buffer,data_length);
data->len = 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;
this->data_struct = payload;
size_t rule_count, offset_start;
encoding_rule_t *rules;
payload_type_t payload_type;
/* get payload type */
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 U_INT_64:
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:
{
/* position of payload lenght field is temporary stored */
this->last_payload_length_position_offset = get_current_buffer_offset(this);
/* payload length is generated like an U_INT_16 */
generate_u_int_type(this, U_INT_16,rules[i].offset);
break;
}
case HEADER_LENGTH:
{
/* position of header length field is temporary stored */
this->header_length_position_offset = get_current_buffer_offset(this);
/* header length is generated like an U_INT_32 */
generate_u_int_type(this ,U_INT_32, rules[i].offset);
break;
}
case SPI_SIZE:
/* spi size is handled as 8 bit unsigned integer */
generate_u_int_type(this, U_INT_8, rules[i].offset);
/* last spi size is temporary stored */
this->last_spi_size = *((u_int8_t *)(this->data_struct + rules[i].offset));
break;
case ADDRESS:
{
/* the Address value is generated from chunk */
generate_from_chunk(this, rules[i].offset);
break;
}
case SPI:
{
/* the SPI value is generated from chunk */
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;
}
/* the data value is generated from chunk */
generate_from_chunk(this, rules[i].offset);
payload_length_position_offset = this->last_payload_length_position_offset;
/* Length of payload is calculated */
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:
{
/* before iterative generate the transforms, store the current payload length position */
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;
/* proposals are stored in a linked list and so accessed */
linked_list_t *proposals = *((linked_list_t **)(this->data_struct + rules[i].offset));
iterator_t *iterator;
payload_t *current_proposal;
/* create forward iterator */
iterator = proposals->create_iterator(proposals,TRUE);
/* every proposal is processed (iterative call )*/
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_current_buffer_offset(this);
this->public.generate_payload(&(this->public),current_proposal);
after_generate_position_offset = get_current_buffer_offset(this);
/* increase size of transform */
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:
{
/* before iterative generate the transforms, store the current length position */
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;
/* create forward iterator */
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_current_buffer_offset(this);
this->public.generate_payload(&(this->public),current_transform);
after_generate_position_offset = get_current_buffer_offset(this);
/* increase size of transform */
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:
{
/* before iterative generate the transform attributes, store the current length position */
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;
/* create forward iterator */
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_current_buffer_offset(this);
this->public.generate_payload(&(this->public),current_attribute);
after_generate_position_offset = get_current_buffer_offset(this);
/* increase size of transform */
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:
{
/* before iterative generate the configuration attributes, store the current length position */
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;
/* create forward iterator */
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_current_buffer_offset(this);
this->public.generate_payload(&(this->public),current_attribute);
after_generate_position_offset = get_current_buffer_offset(this);
/* increase size of transform */
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:
{
/* before iterative generate the traffic_selectors, store the current payload length position */
u_int32_t payload_length_position_offset = this->last_payload_length_position_offset;
/* Length of SA_PAYLOAD is calculated */
u_int16_t length_of_ts_payload = TS_PAYLOAD_HEADER_LENGTH;
u_int16_t int16_val;
/* traffic selectors are stored in a linked list and so accessed */
linked_list_t *traffic_selectors = *((linked_list_t **)(this->data_struct + rules[i].offset));
iterator_t *iterator;
payload_t *current_traffic_selector_substructure;
/* create forward iterator */
iterator = traffic_selectors->create_iterator(traffic_selectors,TRUE);
/* every proposal is processed (iterative call )*/
while (iterator->iterate(iterator, (void **)&current_traffic_selector_substructure))
{
u_int32_t before_generate_position_offset;
u_int32_t after_generate_position_offset;
before_generate_position_offset = get_current_buffer_offset(this);
this->public.generate_payload(&(this->public),current_traffic_selector_substructure);
after_generate_position_offset = get_current_buffer_offset(this);
/* increase size of transform */
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;
return &(this->public);
}
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