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/* -*- c-basic-offset: 8 -*-
rdesktop: A Remote Desktop Protocol client.
Protocol services - Virtual channels
Copyright 2003 Erik Forsberg <forsberg@cendio.se> for Cendio AB
Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 2003-2008
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "rdesktop.h"
#define MAX_CHANNELS 6
#define CHANNEL_CHUNK_LENGTH 1600
#define CHANNEL_FLAG_FIRST 0x01
#define CHANNEL_FLAG_LAST 0x02
#define CHANNEL_FLAG_SHOW_PROTOCOL 0x10
extern RDP_VERSION g_rdp_version;
extern RD_BOOL g_encryption;
VCHANNEL g_channels[MAX_CHANNELS];
unsigned int g_num_channels;
/* FIXME: We should use the information in TAG_SRV_CHANNELS to map RDP5
channels to MCS channels.
The format of TAG_SRV_CHANNELS seems to be
global_channel_no (uint16le)
number_of_other_channels (uint16le)
..followed by uint16les for the other channels.
*/
VCHANNEL *
channel_register(char *name, uint32 flags, void (*callback) (STREAM))
{
VCHANNEL *channel;
if (g_rdp_version < RDP_V5)
return NULL;
if (g_num_channels >= MAX_CHANNELS)
{
logger(Core, Error,
"channel_register(), channel table full, increase MAX_CHANNELS");
return NULL;
}
channel = &g_channels[g_num_channels];
channel->mcs_id = MCS_GLOBAL_CHANNEL + 1 + g_num_channels;
strncpy(channel->name, name, 8);
channel->flags = flags;
channel->process = callback;
g_num_channels++;
return channel;
}
STREAM
channel_init(VCHANNEL * channel, uint32 length)
{
UNUSED(channel);
STREAM s;
s = sec_init(g_encryption ? SEC_ENCRYPT : 0, length + 8);
s_push_layer(s, channel_hdr, 8);
return s;
}
void
channel_send(STREAM s, VCHANNEL * channel)
{
uint32 length, flags;
uint32 thislength, remaining;
uint8 *data;
#ifdef WITH_SCARD
scard_lock(SCARD_LOCK_CHANNEL);
#endif
/* first fragment sent in-place */
s_pop_layer(s, channel_hdr);
length = s->end - s->p - 8;
logger(Protocol, Debug, "channel_send(), channel = %d, length = %d", channel->mcs_id, length);
thislength = MIN(length, CHANNEL_CHUNK_LENGTH);
/* Note: In the original clipboard implementation, this number was
1592, not 1600. However, I don't remember the reason and 1600 seems
to work so.. This applies only to *this* length, not the length of
continuation or ending packets. */
remaining = length - thislength;
flags = (remaining == 0) ? CHANNEL_FLAG_FIRST | CHANNEL_FLAG_LAST : CHANNEL_FLAG_FIRST;
if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
out_uint32_le(s, length);
out_uint32_le(s, flags);
data = s->end = s->p + thislength;
logger(Protocol, Debug, "channel_send(), sending %d bytes with FLAG_FIRST set", thislength);
sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
/* subsequent segments copied (otherwise would have to generate headers backwards) */
while (remaining > 0)
{
thislength = MIN(remaining, CHANNEL_CHUNK_LENGTH);
remaining -= thislength;
flags = (remaining == 0) ? CHANNEL_FLAG_LAST : 0;
if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
logger(Protocol, Debug, "channel_send(), sending %d bytes with flags 0x%x",
thislength, flags);
s = sec_init(g_encryption ? SEC_ENCRYPT : 0, thislength + 8);
out_uint32_le(s, length);
out_uint32_le(s, flags);
out_uint8p(s, data, thislength);
s_mark_end(s);
sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
data += thislength;
}
#ifdef WITH_SCARD
scard_unlock(SCARD_LOCK_CHANNEL);
#endif
}
void
channel_process(STREAM s, uint16 mcs_channel)
{
uint32 length, flags;
uint32 thislength;
VCHANNEL *channel = NULL;
unsigned int i;
STREAM in;
for (i = 0; i < g_num_channels; i++)
{
channel = &g_channels[i];
if (channel->mcs_id == mcs_channel)
break;
}
if (i >= g_num_channels)
return;
in_uint32_le(s, length);
in_uint32_le(s, flags);
if ((flags & CHANNEL_FLAG_FIRST) && (flags & CHANNEL_FLAG_LAST))
{
/* single fragment - pass straight up */
channel->process(s);
}
else
{
/* add fragment to defragmentation buffer */
in = &channel->in;
if (flags & CHANNEL_FLAG_FIRST)
{
if (length > in->size)
{
in->data = (uint8 *) xrealloc(in->data, length);
in->size = length;
}
in->p = in->data;
}
thislength = MIN(s->end - s->p, in->data + in->size - in->p);
memcpy(in->p, s->p, thislength);
in->p += thislength;
if (flags & CHANNEL_FLAG_LAST)
{
in->end = in->p;
in->p = in->data;
channel->process(in);
}
}
}
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