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Viewing changes to channels.c

  • Committer: Bazaar Package Importer
  • Author(s): Sam Johnston
  • Date: 2004-02-04 17:52:26 UTC
  • Revision ID: james.westby@ubuntu.com-20040204175226-87kz4bzs1nimji68
Tags: upstream-1.3.1
Import upstream version 1.3.1

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channels.c
 
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/* -*- c-basic-offset: 8 -*-
 
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   rdesktop: A Remote Desktop Protocol client.
 
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   Protocol services - Virtual channels
 
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   Copyright (C) Erik Forsberg <forsberg@cendio.se> 2003
 
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   Copyright (C) Matthew Chapman 2003
 
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   This program is free software; you can redistribute it and/or modify
 
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   it under the terms of the GNU General Public License as published by
 
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   the Free Software Foundation; either version 2 of the License, or
 
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   (at your option) any later version.
 
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   This program is distributed in the hope that it will be useful,
 
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
 
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
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   GNU General Public License for more details.
 
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   You should have received a copy of the GNU General Public License
 
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   along with this program; if not, write to the Free Software
 
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   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
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*/
 
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#include "rdesktop.h"
 
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#define MAX_CHANNELS                    4
 
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#define CHANNEL_CHUNK_LENGTH            1600
 
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#define CHANNEL_FLAG_FIRST              0x01
 
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#define CHANNEL_FLAG_LAST               0x02
 
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#define CHANNEL_FLAG_SHOW_PROTOCOL      0x10
 
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extern BOOL g_use_rdp5;
 
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extern BOOL g_encryption;
 
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VCHANNEL g_channels[MAX_CHANNELS];
 
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unsigned int g_num_channels;
 
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/* FIXME: We should use the information in TAG_SRV_CHANNELS to map RDP5
 
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   channels to MCS channels.
 
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   The format of TAG_SRV_CHANNELS seems to be
 
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   global_channel_no (uint16le)
 
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   number_of_other_channels (uint16le)
 
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   ..followed by uint16les for the other channels.
 
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*/
 
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VCHANNEL *
 
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channel_register(char *name, uint32 flags, void (*callback) (STREAM))
 
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{
 
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        VCHANNEL *channel;
 
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        if (!g_use_rdp5)
 
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                return NULL;
 
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        if (g_num_channels >= MAX_CHANNELS)
 
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        {
 
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                error("Channel table full, increase MAX_CHANNELS\n");
 
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                return NULL;
 
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        }
 
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        channel = &g_channels[g_num_channels];
 
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        channel->mcs_id = MCS_GLOBAL_CHANNEL + 1 + g_num_channels;
 
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        strncpy(channel->name, name, 8);
 
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        channel->flags = flags;
 
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        channel->process = callback;
 
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        g_num_channels++;
 
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        return channel;
 
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}
 
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STREAM
 
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channel_init(VCHANNEL * channel, uint32 length)
 
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{
 
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        STREAM s;
 
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        s = sec_init(g_encryption ? SEC_ENCRYPT : 0, length + 8);
 
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        s_push_layer(s, channel_hdr, 8);
 
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        return s;
 
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}
 
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void
 
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channel_send(STREAM s, VCHANNEL * channel)
 
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{
 
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        uint32 length, flags;
 
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        uint32 thislength, remaining;
 
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        uint8 *data;
 
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        /* first fragment sent in-place */
 
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        s_pop_layer(s, channel_hdr);
 
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        length = s->end - s->p - 8;
 
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        DEBUG_CLIPBOARD(("channel_send, length = %d\n", length));
 
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        thislength = MIN(length, CHANNEL_CHUNK_LENGTH);
 
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/* Note: In the original clipboard implementation, this number was
 
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   1592, not 1600. However, I don't remember the reason and 1600 seems
 
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   to work so.. This applies only to *this* length, not the length of
 
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   continuation or ending packets. */
 
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        remaining = length - thislength;
 
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        flags = (remaining == 0) ? CHANNEL_FLAG_FIRST | CHANNEL_FLAG_LAST : CHANNEL_FLAG_FIRST;
 
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        if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
 
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                flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
 
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        out_uint32_le(s, length);
 
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        out_uint32_le(s, flags);
 
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        data = s->end = s->p + thislength;
 
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        DEBUG_CLIPBOARD(("Sending %d bytes with FLAG_FIRST\n", thislength));
 
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        sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
 
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        /* subsequent segments copied (otherwise would have to generate headers backwards) */
 
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        while (remaining > 0)
 
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        {
 
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                thislength = MIN(remaining, CHANNEL_CHUNK_LENGTH);
 
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                remaining -= thislength;
 
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                flags = (remaining == 0) ? CHANNEL_FLAG_LAST : 0;
 
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                if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
 
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                        flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
 
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                DEBUG_CLIPBOARD(("Sending %d bytes with flags %d\n", thislength, flags));
 
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                s = sec_init(g_encryption ? SEC_ENCRYPT : 0, thislength + 8);
 
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                out_uint32_le(s, length);
 
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                out_uint32_le(s, flags);
 
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                out_uint8p(s, data, thislength);
 
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                s_mark_end(s);
 
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                sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
 
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                data += thislength;
 
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        }
 
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}
 
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void
 
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channel_process(STREAM s, uint16 mcs_channel)
 
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{
 
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        uint32 length, flags;
 
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        uint32 thislength;
 
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        VCHANNEL *channel = NULL;
 
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        unsigned int i;
 
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        STREAM in;
 
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        for (i = 0; i < g_num_channels; i++)
 
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        {
 
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                channel = &g_channels[i];
 
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                if (channel->mcs_id == mcs_channel)
 
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                        break;
 
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        }
 
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        if (i >= g_num_channels)
 
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                return;
 
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        in_uint32_le(s, length);
 
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        in_uint32_le(s, flags);
 
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        if ((flags & CHANNEL_FLAG_FIRST) && (flags & CHANNEL_FLAG_LAST))
 
152
        {
 
153
                /* single fragment - pass straight up */
 
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                channel->process(s);
 
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        }
 
156
        else
 
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        {
 
158
                /* add fragment to defragmentation buffer */
 
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                in = &channel->in;
 
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                if (flags & CHANNEL_FLAG_FIRST)
 
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                {
 
162
                        if (length > in->size)
 
163
                        {
 
164
                                in->data = xrealloc(in->data, length);
 
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                                in->size = length;
 
166
                        }
 
167
                        in->p = in->data;
 
168
                }
 
169
 
 
170
                thislength = MIN(s->end - s->p, in->data + in->size - in->p);
 
171
                memcpy(in->p, s->p, thislength);
 
172
                in->p += thislength;
 
173
 
 
174
                if (flags & CHANNEL_FLAG_LAST)
 
175
                {
 
176
                        in->end = in->p;
 
177
                        in->p = in->data;
 
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                        channel->process(in);
 
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                }
 
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        }
 
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}