/* Parse an ASN.1 BER header */
RD_BOOL
ber_parse_header(rdpMcs * mcs, STREAM s, int tagval, int *length)
{
int tag, len;
if (tagval > 0xff)
{
in_uint16_be(s, tag);
}
else
{
in_uint8(s, tag);
}
if (tag != tagval)
{
ui_error(mcs->sec->rdp->inst, "expected tag %d, got %d\n", tagval, tag);
return False;
}
in_uint8(s, len);
if (len & 0x80)
{
len &= ~0x80;
*length = 0;
while (len--)
next_be(s, *length);
}
else
*length = len;
return s_check(s);
}
/* Receive a message on the ISO layer, return code */
static STREAM
iso_recv_msg(uint8 * code, uint8 * rdpver)
{
STREAM s;
uint16 length;
uint8 version;
s = tcp_recv(NULL, 4);
if (s == NULL)
return NULL;
in_uint8(s, version);
if (rdpver != NULL)
*rdpver = version;
if (version == 3)
{
in_uint8s(s, 1); /* pad */
in_uint16_be(s, length);
}
else
{
in_uint8(s, length);
if (length & 0x80)
{
length &= ~0x80;
next_be(s, length);
}
}
if (length < 4)
{
error("Bad packet header\n");
return NULL;
}
s = tcp_recv(s, length - 4);
if (s == NULL)
return NULL;
if (version != 3)
return s;
in_uint8s(s, 1); /* hdrlen */
in_uint8(s, *code);
if (*code == ISO_PDU_DT)
{
in_uint8s(s, 1); /* eot */
return s;
}
in_uint8s(s, 5); /* dst_ref, src_ref, class */
return s;
}
/* Receive a packet from tcp and return stream.
* If no ptype then only TPKT header with X.224 is accepted.
* If ptype then Fast-Path packets are accepted too.
* Return NULL on error. */
STREAM
tpkt_recv(rdpIso * iso, uint8 * pcode, isoRecvType * ptype)
{
STREAM s;
int length;
s = tcp_recv(iso->tcp, NULL, 4);
if (s == NULL)
return NULL;
length = tpkt_input_header(s);
if (length >= 0)
{
/* Valid TPKT header, payload is X.224 TPDU */
if (ptype != NULL)
*ptype = ISO_RECV_X224;
s = x224_recv(iso, s, length, pcode);
return s;
}
else if (ptype != NULL)
{
/* Fast-Path header */
uint8 fpInputHeader;
in_uint8(s, fpInputHeader);
ASSERT((fpInputHeader & 3) == 0); /* assume actionCode FASTPATH_OUTPUT_ACTION_FASTPATH */
*ptype = (fpInputHeader & 0x80) ? ISO_RECV_FAST_PATH_ENCRYPTED : ISO_RECV_FAST_PATH;
/* TODO: 0x40 FASTPATH_OUTPUT_SECURE_CHECKSUM indicates salted MAC */
in_uint8(s, length);
if (length & 0x80)
{
length &= ~0x80;
next_be(s, length);
}
s = tcp_recv(iso->tcp, s, length - 4);
return s;
}
return NULL; /* Fast-Path not allowed */
}
/* Receive a message on the ISO layer, return code */
static STREAM
iso_recv_msg(RDPCLIENT * This, uint8 * code, uint8 * rdpver)
{
STREAM s;
uint16 length;
uint8 version;
s = tcp_recv(This, NULL, 4);
if (s == NULL)
return NULL;
in_uint8(s, version);
if (rdpver != NULL)
*rdpver = version;
if (version == 3)
{
in_uint8s(s, 1); /* pad */
in_uint16_be(s, length);
}
else
{
in_uint8(s, length);
if (length & 0x80)
{
length &= ~0x80;
next_be(s, length);
}
}
s = tcp_recv(This, s, length - 4);
if (s == NULL)
return NULL;
if (version != 3)
return s;
in_uint8s(s, 1); /* hdrlen */
in_uint8(s, *code);
if (*code == ISO_PDU_DT)
{
in_uint8s(s, 1); /* eot */
return s;
}
in_uint8s(s, 5); /* dst_ref, src_ref, class */
return s;
}
