path: root/tinySIGCOMP/src/tcomp_message.c

/*
* Copyright (C) 2010-2011 Mamadou Diop.
*
* Contact: Mamadou Diop <diopmamadou(at)doubango[dot]org>
*
* This file is part of Open Source Doubango Framework.
*
* DOUBANGO 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 3 of the License, or
* (at your option) any later version.
*
* DOUBANGO 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.
*
* You should have received a copy of the GNU General Public License
* along with DOUBANGO.
*
*/

/**@file tcomp_message.c
 * @brief  SIGCOMP message as per RFC 3320 subclause 7.
 * A message sent from the compressor dispatcher to the decompressordispatcher.  In case of a message-based transport such as UDP, a
 * SigComp message corresponds to exactly one datagram.  For a stream-based transport such as TCP, the SigComp messages are
 * separated by reserved delimiters.
 *
 * @author Mamadou Diop <diopmamadou(at)yahoo.fr>
 *

 */
#include "tcomp_message.h"
#include "tcomp_nack_codes.h"

#include "tsk_memory.h"
#include "tsk_debug.h"
#include "tsk_binaryutils.h"
#include "tsk_sha1.h"

#include <string.h>

#define MIN_LEN 2
#define HEADER_GET_LEN(message)		(message->headerSigComp & 0x03)
#define HEADER_GET_T(message)		(message->headerSigComp & 0x04)
#define HEADER_IS_VALID(message)	(message->headerSigComp >= 0xf8)

#define HEADER_GET_DEST_VALUE(destination) ( sigcomp_encoding_destination[destination] )
#define HEADER_GET_STATE_LENGTH(length) ( sigcomp_encoding_partial_id_length[length] )

static void initFeedbackItem(tcomp_message_t *message, uint8_t** start_ptr);
static void initStateId(tcomp_message_t *message, uint8_t** start_ptr, uint8_t state_len);
static void initStateful(tcomp_message_t *message, uint8_t** start_ptr, uint8_t* end_ptr);
static void initStateless(tcomp_message_t *message, uint8_t** start_ptr, uint8_t* end_ptr, int32_t *nack_code);
static void initNack(tcomp_message_t *message, uint8_t** start_ptr, uint8_t* end_ptr, int32_t* nack_code);

/*
Creates new SigComp message.
*/
tcomp_message_t* tcomp_message_create(const void* input_ptr, tsk_size_t input_size, tsk_bool_t stream, int32_t* nack_code)
{
    tcomp_message_t *message;

    if(!nack_code) {
        TSK_DEBUG_ERROR("Invalid parameter");
        return tsk_null;
    }

    if(!input_ptr) {
        TSK_DEBUG_ERROR("Invalid parameter");
        *nack_code = NACK_INTERNAL_ERROR;
        return tsk_null;
    }

    if(input_size < MIN_LEN) {
        TSK_DEBUG_ERROR("MESSAGE_TOO_SHORT");
        *nack_code = NACK_MESSAGE_TOO_SHORT;
        return tsk_null;
    }

    if((message = tsk_object_new(tcomp_message_def_t))) {
        uint8_t *dummy_ptr, *end_ptr;
        uint8_t state_len;

        message->startPtr = input_ptr;
        message->stateId = tcomp_buffer_create_null();
        message->remaining_sigcomp_buffer = tcomp_buffer_create_null();
        message->uploaded_UDVM_buffer = tcomp_buffer_create_null();
        message->ret_feedback_buffer= tcomp_buffer_create_null();

        message->isNack = 0;
        dummy_ptr = ((uint8_t*)input_ptr);
        end_ptr = (dummy_ptr + input_size);

        //
        message->totalSize = input_size;
        message->stream_based = stream;
        message->bytecodes_destination = 0;

        /* Get sigcomp header */
        message->headerSigComp = *dummy_ptr;
        dummy_ptr++;

        /* Check message validity --> magic code (11111)? */
        message->isOK = HEADER_IS_VALID(message);
        if(!message->isOK) {
            TSK_DEBUG_ERROR("SigComp Message not valid (magic code mismatch)");
            *nack_code = NACK_INTERNAL_ERROR;
            goto bail;
        }

        /* Feedback item */
        if((HEADER_GET_T(message)!=0)) {
            initFeedbackItem(message, &dummy_ptr);
            if(!message->isOK) {
                goto bail;
            }
        }

        /*
        * If the len field is non-zero, then the SigComp message contains a state identifier
        * to access a state item at the receiving endpoint.
        */
        state_len = HEADER_GET_STATE_LENGTH( HEADER_GET_LEN(message) );
        if(state_len) {
            initStateId(message, &dummy_ptr, state_len);
            initStateful(message, &dummy_ptr, end_ptr);
            TSK_DEBUG_INFO("SigComp - Decompressing stateful message with state id =");
            tcomp_buffer_print(message->stateId);
        }
        else {
            if( !*dummy_ptr && !(*(dummy_ptr+1)&0xf0) ) {
                // "code_len" field of zero --> it's a nack
                initNack(message, &dummy_ptr, end_ptr, nack_code);
            }
            else {
                initStateless(message, &dummy_ptr, end_ptr, nack_code);
            }
        }

        /*
        * The fields (RFC 3320 section 7) except for the "remaining SigComp message" are referred to
        * as the "SigComp header" (note that this may include the uploaded UDVM bytecode).
        */
        if(message->isOK) {
            message->header_size = ( message->totalSize - tcomp_buffer_getSize(message->remaining_sigcomp_buffer));
        }
    }
    else {
        TSK_DEBUG_ERROR("Failed to create new SigComp message");
    }

bail:
    if(message && !message->isOK) {
        TSK_OBJECT_SAFE_FREE(message);
    }

    return message;
}

/*
Iniatizes the feedback item field.
*/
static void initFeedbackItem(tcomp_message_t *message, uint8_t** start_ptr)
{
    /*
     0   1   2   3   4   5   6   7       0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    | 0 |  returned_feedback_field  |   | 1 | returned_feedback_length  |
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
                                       |                               |
                                       :    returned_feedback_field    :
                                       |                               |
                                       +---+---+---+---+---+---+---+---+
    */
    if((**start_ptr) <= 128) {
        tcomp_buffer_referenceBuff(message->ret_feedback_buffer, *start_ptr, 1);
        (void)(*start_ptr++);
    }
    else {
        tcomp_buffer_referenceBuff(message->ret_feedback_buffer, *start_ptr, 1+(**start_ptr&0x7f));
        *start_ptr += tcomp_buffer_getSize(message->ret_feedback_buffer);
    }
}

/*
Initializes the state identifier field.
*/
static void initStateId(tcomp_message_t *message, uint8_t** start_ptr, uint8_t state_len)
{
    tcomp_buffer_referenceBuff(message->stateId, *start_ptr, state_len);
    *start_ptr += state_len;
}

/*
Initializes a stateful SigComp message.
*/
static void initStateful(tcomp_message_t *message, uint8_t** start_ptr, uint8_t* end_ptr)
{
    /*
    +---+---+---+---+---+---+---+---+
    |                               |
    :   partial state identifier    :
    |                               |
    +---+---+---+---+---+---+---+---+
    |                               |
    :   remaining SigComp message   :
    |                               |
    +---+---+---+---+---+---+---+---+
    */
    message->isOK &= (*start_ptr<=end_ptr);
    if(message->isOK) {
        tcomp_buffer_referenceBuff(message->remaining_sigcomp_buffer, *start_ptr,
                                   ((end_ptr-*start_ptr)));
    }
}

/*
Initializes a stateless SigComp message.
*/
static void initStateless(tcomp_message_t *message, uint8_t** start_ptr, uint8_t* end_ptr, int32_t *nack_code)
{
    int has_bytecode = (HEADER_GET_LEN(message) == 0); // No state ==> message contains udvm bytecode
    message->isOK &= has_bytecode;
    if(!message->isOK) {
        return;
    }

    /*
    +---+---+---+---+---+---+---+---+
    |           code_len            |
    +---+---+---+---+---+---+---+---+
    |   code_len    |  destination  |
    +---+---+---+---+---+---+---+---+
    |                               |
    :    uploaded UDVM bytecode     :
    |                               |
    +---+---+---+---+---+---+---+---+
    |                               |
    :   remaining SigComp message   :
    |                               |
    +---+---+---+---+---+---+---+---+
    */
    {
        uint32_t code_len1, bytecodes_len;
        uint8_t code_len2, destination, *bytecodes_uploaded_udvm, *remaining_SigComp_message;

        uint8_t* dummy_ptr = ((uint8_t*)*start_ptr);

        /* Code_len --> 12bits [8+4] */
        code_len1 = *dummy_ptr;
        dummy_ptr++; /* skip first code_len 8bits */
        code_len2 = (*dummy_ptr) & 0xf0; /* code_len 4 remaining bits */
        destination = (*dummy_ptr) & 0x0f; /* 4bits after code_len */
        dummy_ptr++; /* skip code_len 4bits + destination 4bits ==> 1-byte */

        /* Get bytecodes length (12bits) */
        bytecodes_len = ( (code_len1<<4)|(code_len2>>4) );

        /* Starting memory address (code destination address). In UDVM. */
        message->bytecodes_destination = HEADER_GET_DEST_VALUE(destination);
        if((message->bytecodes_destination < 128) || (message->bytecodes_destination > 1024)) {
            TSK_DEBUG_ERROR("INVALID_CODE_LOCATION");
            *nack_code = NACK_INVALID_CODE_LOCATION;
            message->isOK = 0;
            return;
        }

        /* Uploaded UDVM pointer */
        bytecodes_uploaded_udvm = dummy_ptr; /* SigComp header, feedback_item, code_len and destination have been skipped */

        /* Skip uploaded udvm */
        dummy_ptr += bytecodes_len;

        /* remaining SigComp message */
        remaining_SigComp_message = dummy_ptr;

        /* check that remaining sigcomp message is valide */
        if( !(message->isOK &= (remaining_SigComp_message <= end_ptr )) ) {
            TSK_DEBUG_ERROR("MESSAGE_TOO_SHORT");
            *nack_code = NACK_MESSAGE_TOO_SHORT;
            return;
        }

        //
        // Setting buffers
        //
        tcomp_buffer_referenceBuff(message->uploaded_UDVM_buffer, bytecodes_uploaded_udvm, bytecodes_len);
        tcomp_buffer_referenceBuff(message->remaining_sigcomp_buffer, remaining_SigComp_message, ((end_ptr-remaining_SigComp_message)));
    }
}

/*
Initializes a NACK message as per RFC 4077.
*/
static void initNack(tcomp_message_t *message, uint8_t** start_ptr, uint8_t* end_ptr, int32_t* nack_code)
{
    /*
    +---+---+---+---+---+---+---+---+
    |         code_len = 0          |
    +---+---+---+---+---+---+---+---+
    | code_len = 0  |  version = 1  |
    +---+---+---+---+---+---+---+---+
    |          Reason Code          |
    +---+---+---+---+---+---+---+---+
    |  OPCODE of failed instruction |
    +---+---+---+---+---+---+---+---+
    |   PC of failed instruction    |
    |                               |
    +---+---+---+---+---+---+---+---+
    |                               |
    : SHA-1 Hash of failed message  :
    |                               |
    +---+---+---+---+---+---+---+---+
    |                               |
    :         Error Details         :
    |                               |
    +---+---+---+---+---+---+---+---+*/

    uint8_t* dummy_ptr;
    message->isNack = 1;
    if( (end_ptr - *start_ptr)<25 ) {
        *nack_code = NACK_MESSAGE_TOO_SHORT;
        TSK_DEBUG_ERROR("MESSAGE_TOO_SHORT");
        message->isOK = 0;
        return;
    }

    dummy_ptr = ((uint8_t*)*start_ptr);
    dummy_ptr++; /* skip first code_len byte */
    if(!(message->isOK = (*dummy_ptr++ == NACK_VERSION))) {
        return;
    }

    if(!message->nack_info) {
        message->nack_info = tcomp_nackinfo_create();
    }

    message->nack_info->reasonCode = *dummy_ptr++;
    message->nack_info->opcode = *dummy_ptr++;
    message->nack_info->pc = TSK_BINARY_GET_2BYTES(dummy_ptr);
    dummy_ptr+=2;
    memcpy(message->nack_info->sha1, dummy_ptr, TSK_SHA1_DIGEST_SIZE);
    dummy_ptr += TSK_SHA1_DIGEST_SIZE;
    if(dummy_ptr < end_ptr) {
        /* Has error details */
        tcomp_buffer_appendBuff(message->nack_info->details, dummy_ptr, (end_ptr-dummy_ptr));
    }
}





//========================================================
//	SigComp message object definition
//

static tsk_object_t* tcomp_message_ctor(tsk_object_t *self, va_list * app)
{
    tcomp_message_t *message = self;

    if(message) {
    }

    return self;
}

static tsk_object_t* tcomp_message_dtor(tsk_object_t *self)
{
    tcomp_message_t *message = self;

    if(message) {
        TSK_OBJECT_SAFE_FREE(message->stateId);
        TSK_OBJECT_SAFE_FREE(message->remaining_sigcomp_buffer);
        TSK_OBJECT_SAFE_FREE(message->uploaded_UDVM_buffer);
        TSK_OBJECT_SAFE_FREE(message->ret_feedback_buffer);
        TSK_OBJECT_SAFE_FREE(message->nack_info);
    }
    else {
        TSK_DEBUG_WARN("NULL SigComp message.");
    }

    return self;
}

static const tsk_object_def_t tcomp_message_def_s = {
    sizeof(tcomp_message_t),
    tcomp_message_ctor,
    tcomp_message_dtor,
    tsk_null
};
const tsk_object_def_t* tcomp_message_def_t = &tcomp_message_def_s;