/**
* @brief Try to read a complete PDU (NLA, fast-path or tpkt) from the underlying transport.
*
* If possible a complete PDU is read, in case of non blocking transport this might not succeed.
* Except in case of an error the passed stream will point to the last byte read (correct
* position). When the pdu read is completed the stream is sealed and the pointer set to 0
*
* @param[in] transport rdpTransport
* @param[in] s wStream
* @return < 0 on error; 0 if not enough data is available (non blocking mode); > 0 number of
* bytes of the *complete* pdu read
*/
int transport_read_pdu(rdpTransport* transport, wStream* s)
{
int status;
int position;
int pduLength;
BYTE* header;
position = 0;
pduLength = 0;
if (!transport)
return -1;
if (!s)
return -1;
position = Stream_GetPosition(s);
/* Make sure there is enough space for the longest header within the stream */
if (!Stream_EnsureCapacity(s, 4))
return -1;
/* Make sure at least two bytes are read for further processing */
if (position < 2 && (status = transport_read_layer_bytes(transport, s, 2 - position)) != 1)
{
/* No data available at the moment */
return status;
}
/* update position value for further checks */
position = Stream_GetPosition(s);
header = Stream_Buffer(s);
if (transport->NlaMode)
{
/*
* In case NlaMode is set TSRequest package(s) are expected
* 0x30 = DER encoded data with these bits set:
* bit 6 P/C constructed
* bit 5 tag number - sequence
*/
if (header[0] == 0x30)
{
/* TSRequest (NLA) */
if (header[1] & 0x80)
{
if ((header[1] & ~(0x80)) == 1)
{
/* check for header bytes already was readed in previous calls */
if (position < 3
&& (status = transport_read_layer_bytes(transport, s, 3 - position)) != 1)
return status;
pduLength = header[2];
pduLength += 3;
}
else if ((header[1] & ~(0x80)) == 2)
{
/* check for header bytes already was readed in previous calls */
if (position < 4
&& (status = transport_read_layer_bytes(transport, s, 4 - position)) != 1)
return status;
pduLength = (header[2] << 8) | header[3];
pduLength += 4;
}
else
{
WLog_ERR(TAG, "Error reading TSRequest!");
return -1;
}
}
else
{
pduLength = header[1];
pduLength += 2;
}
}
}
else
{
if (header[0] == 0x03)
{
/* TPKT header */
/* check for header bytes already was readed in previous calls */
if (position < 4
&& (status = transport_read_layer_bytes(transport, s, 4 - position)) != 1)
return status;
pduLength = (header[2] << 8) | header[3];
/* min and max values according to ITU-T Rec. T.123 (01/2007) section 8 */
if (pduLength < 7 || pduLength > 0xFFFF)
{
WLog_ERR(TAG, "tpkt - invalid pduLength: %d", pduLength);
return -1;
}
}
else
{
/* Fast-Path Header */
if (header[1] & 0x80)
{
/* check for header bytes already was readed in previous calls */
if (position < 3
&& (status = transport_read_layer_bytes(transport, s, 3 - position)) != 1)
return status;
pduLength = ((header[1] & 0x7F) << 8) | header[2];
}
else
pduLength = header[1];
/*
* fast-path has 7 bits for length so the maximum size, including headers is 0x8000
* The theoretical minimum fast-path PDU consists only of two header bytes plus one
* byte for data (e.g. fast-path input synchronize pdu)
*/
if (pduLength < 3 || pduLength > 0x8000)
{
WLog_ERR(TAG, "fast path - invalid pduLength: %d", pduLength);
return -1;
}
}
}
if (!Stream_EnsureCapacity(s, Stream_GetPosition(s) + pduLength))
return -1;
status = transport_read_layer_bytes(transport, s, pduLength - Stream_GetPosition(s));
if (status != 1)
return status;
if (Stream_GetPosition(s) >= pduLength)
WLog_Packet(WLog_Get(TAG), WLOG_TRACE, Stream_Buffer(s), pduLength, WLOG_PACKET_INBOUND);
Stream_SealLength(s);
Stream_SetPosition(s, 0);
return Stream_Length(s);
}
/**
* @brief Try to read a complete PDU (NLA, fast-path or tpkt) from the underlying transport.
*
* If possible a complete PDU is read, in case of non blocking transport this might not succeed.
* Except in case of an error the passed stream will point to the last byte read (correct
* position). When the pdu read is completed the stream is sealed and the pointer set to 0
*
* @param[in] transport rdpTransport
* @param[in] s wStream
* @return < 0 on error; 0 if not enough data is available (non blocking mode); > 0 number of
* bytes of the *complete* pdu read
*/
int transport_read_pdu(rdpTransport* transport, wStream* s)
{
int status;
int position;
int pduLength;
BYTE *header;
position = 0;
pduLength = 0;
if (!transport)
return -1;
if (!s)
return -1;
position = Stream_GetPosition(s);
/* Make sure there is enough space for the longest header within the stream */
Stream_EnsureCapacity(s, 4);
/* Make sure at least two bytes are read for futher processing */
if (position < 2 && (status = transport_read_layer_bytes(transport, s, 2 - position)) != 1)
{
/* No data available at the moment */
return status;
}
header = Stream_Buffer(s);
if (transport->NlaMode)
{
/*
* In case NlaMode is set TSRequest package(s) are expected
* 0x30 = DER encoded data with these bits set:
* bit 6 P/C constructed
* bit 5 tag number - sequence
*/
if (header[0] == 0x30)
{
/* TSRequest (NLA) */
if (header[1] & 0x80)
{
if ((header[1] & ~(0x80)) == 1)
{
if ((status = transport_read_layer_bytes(transport, s, 1)) != 1)
return status;
pduLength = header[2];
pduLength += 3;
}
else if ((header[1] & ~(0x80)) == 2)
{
if ((status = transport_read_layer_bytes(transport, s, 2)) != 1)
return status;
pduLength = (header[2] << 8) | header[3];
pduLength += 4;
}
else
{
fprintf(stderr, "Error reading TSRequest!\n");
return -1;
}
}
else
{
pduLength = header[1];
pduLength += 2;
}
}
}
else
{
if (header[0] == 0x03)
{
/* TPKT header */
if ((status = transport_read_layer_bytes(transport, s, 2)) != 1)
return status;
pduLength = (header[2] << 8) | header[3];
/* min and max values according to ITU-T Rec. T.123 (01/2007) section 8 */
if (pduLength < 7 || pduLength > 0xFFFF)
{
fprintf(stderr, "%s: tpkt - invalid pduLength: %d\n", __FUNCTION__, pduLength);
return -1;
}
}
else
{
/* Fast-Path Header */
if (header[1] & 0x80)
{
if ((status = transport_read_layer_bytes(transport, s, 1)) != 1)
return status;
pduLength = ((header[1] & 0x7F) << 8) | header[2];
}
else
pduLength = header[1];
/*
* fast-path has 7 bits for length so the maximum size, including headers is 0x8000
* The theoretical minimum fast-path PDU consists only of two header bytes plus one
* byte for data (e.g. fast-path input synchronize pdu)
*/
if (pduLength < 3 || pduLength > 0x8000)
{
fprintf(stderr, "%s: fast path - invalid pduLength: %d\n", __FUNCTION__, pduLength);
return -1;
}
}
}
Stream_EnsureCapacity(s, Stream_GetPosition(s) + pduLength);
status = transport_read_layer_bytes(transport, s, pduLength - Stream_GetPosition(s));
if (status != 1)
return status;
#ifdef WITH_DEBUG_TRANSPORT
/* dump when whole PDU is read */
if (Stream_GetPosition(s) >= pduLength)
{
fprintf(stderr, "Local < Remote\n");
winpr_HexDump(Stream_Buffer(s), pduLength);
}
#endif
if (Stream_GetPosition(s) >= pduLength)
WLog_Packet(transport->log, WLOG_TRACE, Stream_Buffer(s), pduLength, WLOG_PACKET_INBOUND);
Stream_SealLength(s);
Stream_SetPosition(s, 0);
return Stream_Length(s);
}
