void rdp_write_header(rdpRdp* rdp, STREAM* s, UINT16 length, UINT16 channel_id)
{
int body_length;
enum DomainMCSPDU MCSPDU;
MCSPDU = (rdp->settings->ServerMode) ? DomainMCSPDU_SendDataIndication : DomainMCSPDU_SendDataRequest;
if ((rdp->sec_flags & SEC_ENCRYPT) && (rdp->settings->EncryptionMethods == ENCRYPTION_METHOD_FIPS))
{
int pad;
body_length = length - RDP_PACKET_HEADER_MAX_LENGTH - 16;
pad = 8 - (body_length % 8);
if (pad != 8)
length += pad;
}
mcs_write_domain_mcspdu_header(s, MCSPDU, length, 0);
per_write_integer16(s, rdp->mcs->user_id, MCS_BASE_CHANNEL_ID); /* initiator */
per_write_integer16(s, channel_id, 0); /* channelId */
stream_write_BYTE(s, 0x70); /* dataPriority + segmentation */
/*
* We always encode length in two bytes, eventhough we could use
* only one byte if length <= 0x7F. It is just easier that way,
* because we can leave room for fixed-length header, store all
* the data first and then store the header.
*/
length = (length - RDP_PACKET_HEADER_MAX_LENGTH) | 0x8000;
stream_write_UINT16_be(s, length); /* userData (OCTET_STRING) */
}
int ber_write_length(wStream* s, int length)
{
if (length > 0x7F)
{
stream_write_BYTE(s, 0x82);
stream_write_UINT16_be(s, length);
return 3;
}
else
{
stream_write_BYTE(s, length);
return 1;
}
}
int ber_write_integer(wStream* s, UINT32 value)
{
ber_write_universal_tag(s, BER_TAG_INTEGER, FALSE);
if (value <= 0xFF)
{
ber_write_length(s, 1);
stream_write_BYTE(s, value);
return 2;
}
else if (value < 0xFF80)
{
ber_write_length(s, 2);
stream_write_UINT16_be(s, value);
return 3;
}
else if (value < 0xFF8000)
{
ber_write_length(s, 3);
stream_write_BYTE(s, (value >> 16));
stream_write_UINT16_be(s, (value & 0xFFFF));
return 4;
}
int der_write_length(wStream* s, int length)
{
if (length > 0x7F && length <= 0xFF)
{
stream_write_BYTE(s, 0x81);
stream_write_BYTE(s, length);
return 2;
}
else if (length > 0xFF)
{
stream_write_BYTE(s, 0x82);
stream_write_UINT16_be(s, length);
return 3;
}
else
{
stream_write_BYTE(s, length);
return 1;
}
}
void tpkt_write_header(wStream* s, UINT16 length)
{
stream_write_BYTE(s, 3); /* version */
stream_write_BYTE(s, 0); /* reserved */
stream_write_UINT16_be(s, length); /* length */
}