decode.c

wm PNE 3.3 source code, running at more than vxworks6.x version.

		   ATVALUE_T	id,
		   bits8_t	flags)
{
bits8_t buff;

if ((A_DecodeTypeClass(stream) != flags) ||
    (A_DecodeTypeValue(stream, errp) != id)) {
    if (*errp == 0)
        *errp = AE_WRONG_TYPE;
    return(0);
    }

if ((A_DecodeLength(stream, errp) != 1) || *errp) {
    if (*errp == 0)
        *errp = AE_WRONG_LENGTH;
    return(0);
    }

if (Lcl_Read(stream, &buff, 1) != 1) {
    *errp = AE_WRONG_LENGTH;
    return(0);
    }

return(buff);
}

/********************
A_DecodeIntegerData

PURPOSE:  Pull an integer from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the data field.
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	ALENGTH_T	Length of contents field, from the ASN.1 header
	int *		Receives an error code, if any.

Returns: INT_32_T	(See note below)

NOTE: If the received value is really unsigned, then the caller should
merely cast the value returned by this procedure to an UINT_32_T.

WARNING: If the integer occupies more than 4 octets, then high order precision
will be lost, including the sign bit.  For unsigned values in which the
basic value occupies all 4 octets, the sign octet, containing a zero sign
bit, will be lost but will not damage the returned value.
********************/
INT_32_T
  A_DecodeIntegerData(LCL_FILE  *stream,
		      ALENGTH_T	 length,
		      int       *errp)
{
  INT_32_T ivalue = 0;
  int	 firstone = 1;
  OCTET_T	 oct;

  while(length-- != 0) {
    oct = (OCTET_T) Lcl_Getc(stream);
    if (Lcl_Eof(stream)) {
        *errp = AE_PREMATURE_END;
        return ivalue;
	}

    /* See whether we are receiving something that has the sign bit set, or
       if this is a 5 byte unsigned int check the first byte, it must be 0 */
    if (firstone) {
	firstone = 0;
	if ((length == 4) && (oct != 0)) {
	    *errp = AE_WRONG_VALUE;
	    return ivalue;
	    }
	if (oct & (OCTET_T)0x80)
	    ivalue = (INT_32_T)-1;
	}
/*lint -e703	*/
    ivalue <<= 8;
/*lint +e703	*/
    ivalue |= oct;	/* 'oct' better not be sign extended!!!	*/
    }
  return ivalue;
}

/********************
A_DecodeInteger

PURPOSE:  Pull an integer from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the integer's ASN.1 type field.
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	int *		Receives an error code, if any.

Returns: INT_32_T;
********************/
INT_32_T
  A_DecodeInteger(LCL_FILE *stream,
		  int      *errp)
{
  ALENGTH_T int_length;

  (void) A_DecodeTypeValue(stream, errp);
  int_length = A_DecodeLength(stream, errp);
  if (*errp == 0) {
    if (int_length > 5)
      *errp = AE_WRONG_VALUE;
    else
      return A_DecodeIntegerData(stream, int_length, errp);
  }

  return(0);

}

/********************
A_DecodeIntegerWTC

PURPOSE:  Pull an integer from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the integer's ASN.1 type field.
	  As we pull off the class and type we check them against
	  the arguments to make sure they are correct.
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	int *		Receives an error code, if any.
	ATVALUE_T	The type value
	OCTET_T		A_IDC_MASK flag values

Returns: INT_32_T;
********************/
INT_32_T
  A_DecodeIntegerWTC(LCL_FILE *	stream,
		     int      *	errp,
		     ATVALUE_T	id,
		     OCTET_T	flags)
{
  ALENGTH_T int_length;

  if ((A_DecodeTypeClass(stream) != flags) ||
      (A_DecodeTypeValue(stream, errp) != id)) {
      if (*errp == 0)
	  *errp = AE_WRONG_TYPE;
      return (0);
      }

  int_length = A_DecodeLength(stream, errp);
  if (*errp == 0) {
    if (int_length > 5)
      *errp = AE_WRONG_VALUE;
    else
      return A_DecodeIntegerData(stream, int_length, errp);
  }

  return(0);

}

/********************
A_DecodeObjectIdData

PURPOSE:  Pull an object identifier from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the data field.
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	ALENGTH_T	Length of contents field, from the ASN.1 header
	OBJ_ID_T *	Object identifier structure to receive the object id.
			The "component_list" will be "malloc"ed.
			component_list == (OIDC_T *)0 indicates that
			there is no component_list.
	int *		Receives an error code, if any.

Returns: Nothing
********************/
void
  A_DecodeObjectIdData(LCL_FILE  *stream,
		       ALENGTH_T  length,
		       OBJ_ID_T  *objp,
		       int       *errp)
{
  ALENGTH_T content_offset;	/* Offset in stream where contents begins */
  int left;			/* Count of unused contents bytes */
  int subids;			/* Number of subidentifiers	*/
  int subid_num;

  OIDC_T	subid_val;	/* Value of a subidentifier */
  OIDC_T	*cp;
  unsigned char	c, first_c;

  objp->num_components = 0;
  objp->component_list = 0;

  /* Remember where the contents begins */
  content_offset = Lcl_Tell(stream);

  /* Count the number of components */
  for(subids = 0, left = (int)length; left > 0;) {
    first_c = (unsigned char)Lcl_Getc(stream);
    if (Lcl_Eof(stream)) {
      *errp = AE_PREMATURE_END;
      return;
    }
    left--;

    /* if its not the last (only) byte, step through the rest of the bytes */
    if (first_c & 0x80) {
      int subid_bytes;		/* number of bytes in this sub id */
      int subid_done;		/* flag to see if the sub id is finished */

      for(subid_bytes = 2, subid_done = 0; left; subid_bytes++) {
	c = (unsigned char)Lcl_Getc(stream);
	if (Lcl_Eof(stream)) {
	  *errp = AE_PREMATURE_END;
	  return;
	}
	left--;

	if ((c & 0x80) == 0) {
	  subid_done = 1;
	  break;
	}
      }

      if ((subid_done == 0) || (subid_bytes > 5) ||
	  ((subid_bytes == 5) && (first_c > 0x8f))) {
	*errp = AE_WRONG_LENGTH;
	return;
      }
    }

    /* finally update the count of the subids */
    subids++;

    if (subids > 128) {
      *errp = AE_WRONG_LENGTH;
      return;
    }
  }

  (void) Lcl_Seek(stream, content_offset, 0);

  /* Null object id if no subidentifier fields */
  if (subids == 0)
    return;

  /* Try to get space for the components list */
  cp = (OIDC_T *)SNMP_memory_alloc((unsigned int)(sizeof(OIDC_T) * (subids + 1)));
  if (cp == 0) {
    *errp = AE_ALLOC_FAILURE;
    return;
  }

  objp->num_components = subids + 1;
  objp->component_list = cp;

  /* Decode the subids and components */
  for (subid_num = 0; subid_num < subids; subid_num++) {
    /* Decode the subidentifier */
    for (subid_val = 0;;) {
      c = (unsigned char)Lcl_Getc(stream);
      if (Lcl_Eof(stream)) {
	*errp = AE_PREMATURE_END;
	SNMP_memory_free(objp->component_list);
	objp->component_list = 0;
	objp->num_components = 0;
	return;
      }
      subid_val <<= 7;
      subid_val |= (OIDC_T)(c & 0x7F);
      if (!(c & 0x80))
	break;
    }

    /* Is this the first subidentifier?			*/
    /* i.e. the one that contains TWO components?	*/
    if (subid_num == 0) {
      if (subid_val < 40) {
	*cp++ = 0;
	*cp++ = subid_val;
      }
      else {
	if (subid_val < 80) {
	  *cp++ = 1;
	  *cp++ = subid_val - 40;
	}
	else {
	  *cp++ = 2;
	  *cp++ = subid_val - 80;
	}
      }
    }
    else { /* subid_num != 0, i.e. this is not the first subidentifier */
      *cp++ = subid_val;
    }
  }

  return;
}

/********************
A_DecodeObjectId

PURPOSE:  Pull an object identifer from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the object identifier's ASN.1 type field.
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	OBJ_ID_T *	Object identifier structure to receive the object id.
			The "component_list" will be "malloc"ed.
			component_list == (OIDC_T *)0 indicates that
			there is no component_list.
	int *		Receives an error code, if any.
		
Returns: Nothing
********************/

void
  A_DecodeObjectId(LCL_FILE *stream,
		   OBJ_ID_T *objp,
  		   int      *errp)
{
  ALENGTH_T leng;
  (void) A_DecodeTypeValue(stream, errp);
  leng = A_DecodeLength(stream, errp);
  if (*errp == 0)
    A_DecodeObjectIdData(stream, leng, objp, errp);
  return;
}

/********************
A_DecodeObjectIdWTC

PURPOSE:  Pull an object identifer from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the object identifier's ASN.1 type field.
	  This version does type checking
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	OBJ_ID_T *	Object identifier structure to receive the object id.
			The "component_list" will be "malloc"ed.
			component_list == (OIDC_T *)0 indicates that
			there is no component_list.
	int *		Receives an error code, if any.
	ATVALUE_T	The type value
	OCTET_T		A_IDC_MASK flag values

		
Returns: Nothing
********************/

void
  A_DecodeObjectIdWTC(LCL_FILE  *stream,
		      OBJ_ID_T  *objp,
		      int       *errp,
		      ATVALUE_T	 id,
		      OCTET_T	 flags)
{
  ALENGTH_T leng;
  if ((A_DecodeTypeClass(stream) != flags) ||
      (A_DecodeTypeValue(stream, errp) != id)) {
      if (*errp == 0)
	  *errp = AE_WRONG_TYPE;
      return;
      }
  leng = A_DecodeLength(stream, errp);
  if (*errp == 0)
    A_DecodeObjectIdData(stream, leng, objp, errp);
  return;
}

/* We only install ui64 routine if the type is installed */
#if (ENVOY_USE_V2_TYPES)
/********************
A_DecodeInteger64Data

PURPOSE:  Pull up to a 64 bit integer from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the data field.
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	ALENGTH_T	Length of contents field, from the ASN.1 header
	UINT_64_T *	Space for the received int
	int *		Receives an error code, if any.

Returns: void

WARNING: If the integer occupies more than 8 octets, then high order precision
will be lost, including the sign bit.  For unsigned values in which the
basic value occupies all 8 octets, the sign octet, containing a zero sign
bit, will be lost but will not damage the returned value.
********************/
void
  A_DecodeInteger64Data(LCL_FILE   *stream,
			 ALENGTH_T  length,
			 UINT_64_T *value,
			 int       *errp)
{
  int	 firstone = 1;
  OCTET_T	 oct;

  value->high = value->low = 0;
  while(length-- != 0) {
    oct = (OCTET_T) Lcl_Getc(stream);
    if (Lcl_Eof(stream)) {
      *errp = AE_PREMATURE_END;
      return;
    }

    /* See whether we are receiving something that has the sign bit set */
    if (firstone) {
      firstone = 0;
      if ((length == 8) && (oct != 0)) {
	*errp = AE_WRONG_VALUE;
	return;
        }

      if (oct & (OCTET_T)0x80) {
	value->high = (UINT_32_T)0xFFFFFFFFL;
	value->low  = (UINT_32_T)0xFFFFFFFFL;
        }
    }

    /* Decide which of the two words to put the octet into   */
    /* if length >= 4 we are working on the high order bytes */
    /* equal sign is because we already decremented length   */
    if (length >= 4) {
	value->high <<= 8;
	value->high |= oct;	/* 'oct' better not be sign extended!!!	*/
        }
    else {
	value->low <<= 8;
	value->low |= oct;	/* 'oct' better not be sign extended!!!	*/
        }
  }
  return;
}

/********************
A_DecodeInteger64

PURPOSE:  Pull up to a 64 bit integer from an ASN.1 stream.
	  The data stream is read using the local I/O package.
	  On entry stream pointer should be positioned to the first byte
	  of the integer's ASN.1 type field.
	  On exit, the stream pointer will be positioned to at the start
	  of the next ASN.1 type field.

PARAMETERS
	LCL_FILE *	Stream descriptor
	UINT_64_T *	Space to receive the int
	int *		Receives an error code, if any.

Returns: INT_32_T;
********************/
void
  A_DecodeInteger64(LCL_FILE  *	stream,
		    UINT_64_T *	value,
		    int       *	errp)
{
  ALENGTH_T int_length;
  
  (void) A_DecodeTypeValue(stream, errp);

  int_length = A_DecodeLength(stream, errp);
  if (*errp == 0) {
    if (int_length > 9)
      *errp = AE_WRONG_VALUE;
    else
      A_DecodeInteger64Data(stream, int_length, value, errp);
  }

  return;
}
#endif /* #if (ENVOY_USE_V2_TYPES) */