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/*
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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
xrdp: A Remote Desktop Protocol server.
Copyright (C) Jay Sorg 2006
channel layer
*/
#include "libxrdp.h"
/* todo, move these to constants.h */
//#define CHANNEL_CHUNK_LENGTH 1600 /* todo, why is this so small? */
#define CHANNEL_CHUNK_LENGTH 8192
#define CHANNEL_FLAG_FIRST 0x01
#define CHANNEL_FLAG_LAST 0x02
#define CHANNEL_FLAG_SHOW_PROTOCOL 0x10
/*****************************************************************************/
/* returns pointer or nil on error */
static struct mcs_channel_item* APP_CC
xrdp_channel_get_item(struct xrdp_channel* self, int channel_id)
{
struct mcs_channel_item* channel;
channel = (struct mcs_channel_item*)
list_get_item(self->mcs_layer->channel_list, channel_id);
return channel;
}
/*****************************************************************************/
struct xrdp_channel* APP_CC
xrdp_channel_create(struct xrdp_sec* owner, struct xrdp_mcs* mcs_layer)
{
struct xrdp_channel* self;
self = (struct xrdp_channel*)g_malloc(sizeof(struct xrdp_channel), 1);
self->sec_layer = owner;
self->mcs_layer = mcs_layer;
return self;
}
/*****************************************************************************/
/* returns error */
void APP_CC
xrdp_channel_delete(struct xrdp_channel* self)
{
if (self == 0)
{
return;
}
g_free(self);
}
/*****************************************************************************/
/* returns error */
int APP_CC
xrdp_channel_init(struct xrdp_channel* self, struct stream* s)
{
if (xrdp_sec_init(self->sec_layer, s) != 0)
{
return 1;
}
s_push_layer(s, channel_hdr, 8);
return 0;
}
/*****************************************************************************/
/* returns error */
/* This sends data out to the secure layer, breaking up the data to
CHANNEL_CHUNK_LENGTH as needed. This can end up sending many packets. */
int APP_CC
xrdp_channel_send(struct xrdp_channel* self, struct stream* s, int channel_id)
{
int length;
int flags;
int thislength;
int remaining;
char* data;
struct mcs_channel_item* channel;
channel = xrdp_channel_get_item(self, channel_id);
if (channel == 0)
{
return 1;
}
s_pop_layer(s, channel_hdr);
length = (int)((s->end - s->p) - 8);
thislength = MIN(length, CHANNEL_CHUNK_LENGTH);
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);
s->end = s->p + thislength;
data = s->end;
if (xrdp_sec_send(self->sec_layer, s, channel->chanid) != 0)
{
return 1;
}
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;
}
if (xrdp_sec_init(self->sec_layer, s) != 0)
{
return 1;
}
out_uint32_le(s, length);
out_uint32_le(s, flags);
/* this is copying a later part of the stream up to the front */
out_uint8a(s, data, thislength);
s_mark_end(s);
if (xrdp_sec_send(self->sec_layer, s, channel->chanid) != 0)
{
return 1;
}
data += thislength;
}
return 0;
}
/*****************************************************************************/
/* returns error */
/* this will inform the callback, whatever it is that some channel data is
ready. the default for this is a call to xrdp_wm.c. */
static int APP_CC
xrdp_channel_call_callback(struct xrdp_channel* self, struct stream* s,
int channel_id)
{
struct xrdp_session* session;
int rv;
int size;
rv = 0;
session = self->sec_layer->rdp_layer->session;
if (session != 0)
{
if (session->callback != 0)
{
size = (int)(s->end - s->p);
/* in xrdp_wm.c */
rv = session->callback(session->id, 0x5555, channel_id, size,
(long)s->p, 0);
}
else
{
g_writeln("in xrdp_channel_process1, session->callback is nil");
}
}
else
{
g_writeln("in xrdp_channel_process1, session is nil");
}
return rv;
}
/*****************************************************************************/
/* returns error */
/* This is called from the secure layer to process an incomming non global
channel packet. It copies the channel data to a special stream contained
in the channel struct(the one in xrdp_mcs->channel_list) untill the
whole data message is ready.
'chanid' passed in here is the mcs channel id so it MCS_GLOBAL_CHANNEL
plus something. */
int APP_CC
xrdp_channel_process(struct xrdp_channel* self, struct stream* s,
int chanid)
{
int length;
int flags;
int thislength;
int rv;
int channel_id;
struct stream* in_s;
struct mcs_channel_item* channel;
/* this assumes that the channels are in order of chanid(mcs channel id)
but they should be, see xrdp_sec_process_mcs_data_channels
the first channel should be MCS_GLOBAL_CHANNEL + 1, second
one should be MCS_GLOBAL_CHANNEL + 2, and so on */
channel_id = (chanid - MCS_GLOBAL_CHANNEL) - 1;
channel = xrdp_channel_get_item(self, channel_id);
if (channel == 0)
{
g_writeln("xrdp_channel_process, channel not found");
return 1;
}
rv = 0;
in_uint32_le(s, length);
in_uint32_le(s, flags);
if ((flags & CHANNEL_FLAG_FIRST) && (flags & CHANNEL_FLAG_LAST))
{
rv = xrdp_channel_call_callback(self, s, channel_id);
}
else
{
if (channel->in_s == 0)
{
make_stream(channel->in_s);
}
in_s = channel->in_s;
if (flags & CHANNEL_FLAG_FIRST)
{
init_stream(in_s, length);
}
thislength = MIN(s->end - s->p, (in_s->data + in_s->size) - in_s->p);
out_uint8a(in_s, s->p, thislength);
if (flags & CHANNEL_FLAG_LAST)
{
in_s->end = in_s->p;
in_s->p = in_s->data;
rv = xrdp_channel_call_callback(self, in_s, channel_id);
}
}
return rv;
}
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