/* -*- c-basic-offset: 8 -*-   rdesktop: A Remote Desktop Protocol client.   Protocol services - Virtual channels   Copyright (C) Erik Forsberg <forsberg@cendio.se> 2003   Copyright (C) Matthew Chapman 2003-2007   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.*/#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	0x10extern RD_BOOL g_use_rdp5;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_use_rdp5)		return NULL;	if (g_num_channels >= MAX_CHANNELS)	{		error("Channel table full, increase MAX_CHANNELS\n");		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;}STREAMchannel_init(VCHANNEL * channel, uint32 length){	STREAM s;	s = sec_init(g_encryption ? SEC_ENCRYPT : 0, length + 8);	s_push_layer(s, channel_hdr, 8);	return s;}voidchannel_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;	DEBUG_CHANNEL(("channel_send, length = %d\n", 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;	DEBUG_CHANNEL(("Sending %d bytes with FLAG_FIRST\n", 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;		DEBUG_CHANNEL(("Sending %d bytes with flags %d\n", 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}voidchannel_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);		}	}}