base/applications/mstsc/channels.c

   1 /* -*- c-basic-offset: 8 -*-
   2    rdesktop: A Remote Desktop Protocol client.
   3    Protocol services - Virtual channels
   4    Copyright (C) Erik Forsberg <forsberg@cendio.se> 2003
   5    Copyright (C) Matthew Chapman 2003-2005
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License along
  18    with this program; if not, write to the Free Software Foundation, Inc.,
  19    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include <precomp.h>
  23
  24 #define MAX_CHANNELS                    6
  25 #define CHANNEL_CHUNK_LENGTH            1600
  26 #define CHANNEL_FLAG_FIRST              0x01
  27 #define CHANNEL_FLAG_LAST               0x02
  28 #define CHANNEL_FLAG_SHOW_PROTOCOL      0x10
  29
  30 extern BOOL g_use_rdp5;
  31 extern BOOL g_encryption;
  32
  33 VCHANNEL g_channels[MAX_CHANNELS];
  34 unsigned int g_num_channels;
  35
  36 /* FIXME: We should use the information in TAG_SRV_CHANNELS to map RDP5
  37    channels to MCS channels.
  38
  39    The format of TAG_SRV_CHANNELS seems to be
  40
  41    global_channel_no (uint16le)
  42    number_of_other_channels (uint16le)
  43    ..followed by uint16les for the other channels.
  44 */
  45
  46 VCHANNEL *
  47 channel_register(char *name, uint32 flags, void (*callback) (STREAM))
  48 {
  49         VCHANNEL *channel;
  50
  51         if (!g_use_rdp5)
  52                 return NULL;
  53
  54         if (g_num_channels >= MAX_CHANNELS)
  55         {
  56                 error("Channel table full, increase MAX_CHANNELS\n");
  57                 return NULL;
  58         }
  59
  60         channel = &g_channels[g_num_channels];
  61         channel->mcs_id = MCS_GLOBAL_CHANNEL + 1 + g_num_channels;
  62         strncpy(channel->name, name, 8);
  63         channel->flags = flags;
  64         channel->process = callback;
  65         g_num_channels++;
  66         return channel;
  67 }
  68
  69 STREAM
  70 channel_init(VCHANNEL * channel, uint32 length)
  71 {
  72         STREAM s;
  73
  74         s = sec_init(g_encryption ? SEC_ENCRYPT : 0, length + 8);
  75         s_push_layer(s, channel_hdr, 8);
  76         return s;
  77 }
  78
  79 void
  80 channel_send(STREAM s, VCHANNEL * channel)
  81 {
  82         uint32 length, flags;
  83         uint32 thislength, remaining;
  84         uint8 *data;
  85
  86         /* first fragment sent in-place */
  87         s_pop_layer(s, channel_hdr);
  88         length = s->end - s->p - 8;
  89
  90         DEBUG_CHANNEL(("channel_send, length = %d\n", length));
  91
  92         thislength = MIN(length, CHANNEL_CHUNK_LENGTH);
  93 /* Note: In the original clipboard implementation, this number was
  94    1592, not 1600. However, I don't remember the reason and 1600 seems
  95    to work so.. This applies only to *this* length, not the length of
  96    continuation or ending packets. */
  97         remaining = length - thislength;
  98         flags = (remaining == 0) ? CHANNEL_FLAG_FIRST | CHANNEL_FLAG_LAST : CHANNEL_FLAG_FIRST;
  99         if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
 100                 flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
 101
 102         out_uint32_le(s, length);
 103         out_uint32_le(s, flags);
 104         data = s->end = s->p + thislength;
 105         DEBUG_CHANNEL(("Sending %d bytes with FLAG_FIRST\n", thislength));
 106         sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
 107
 108         /* subsequent segments copied (otherwise would have to generate headers backwards) */
 109         while (remaining > 0)
 110         {
 111                 thislength = MIN(remaining, CHANNEL_CHUNK_LENGTH);
 112                 remaining -= thislength;
 113                 flags = (remaining == 0) ? CHANNEL_FLAG_LAST : 0;
 114                 if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
 115                         flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
 116
 117                 DEBUG_CHANNEL(("Sending %d bytes with flags %d\n", thislength, flags));
 118
 119                 s = sec_init(g_encryption ? SEC_ENCRYPT : 0, thislength + 8);
 120                 out_uint32_le(s, length);
 121                 out_uint32_le(s, flags);
 122                 out_uint8p(s, data, thislength);
 123                 s_mark_end(s);
 124                 sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
 125
 126                 data += thislength;
 127         }
 128 }
 129
 130 void
 131 channel_process(STREAM s, uint16 mcs_channel)
 132 {
 133         uint32 length, flags;
 134         uint32 thislength;
 135         VCHANNEL *channel = NULL;
 136         unsigned int i;
 137         STREAM in;
 138
 139         for (i = 0; i < g_num_channels; i++)
 140         {
 141                 channel = &g_channels[i];
 142                 if (channel->mcs_id == mcs_channel)
 143                         break;
 144         }
 145
 146         if (i >= g_num_channels)
 147                 return;
 148
 149         in_uint32_le(s, length);
 150         in_uint32_le(s, flags);
 151         if ((flags & CHANNEL_FLAG_FIRST) && (flags & CHANNEL_FLAG_LAST))
 152         {
 153                 /* single fragment - pass straight up */
 154                 channel->process(s);
 155         }
 156         else
 157         {
 158                 /* add fragment to defragmentation buffer */
 159                 in = &channel->in;
 160                 if (flags & CHANNEL_FLAG_FIRST)
 161                 {
 162                         if (length > in->size)
 163                         {
 164                                 in->data = (uint8 *) xrealloc(in->data, length);
 165                                 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;
 178                         channel->process(in);
 179                 }
 180         }
 181 }