git.sesse.net Git - rdpsrv/blob - 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
   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
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "rdesktop.h"
  23
  24 #define MAX_CHANNELS                    4
  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_num_channels >= MAX_CHANNELS)
  52         {
  53                 error("Channel table full, increase MAX_CHANNELS\n");
  54                 return NULL;
  55         }
  56
  57         channel = &g_channels[g_num_channels];
  58         channel->mcs_id = MCS_GLOBAL_CHANNEL + 1 + g_num_channels;
  59         strncpy(channel->name, name, 8);
  60         channel->flags = flags;
  61         channel->process = callback;
  62         g_num_channels++;
  63         return channel;
  64 }
  65
  66 STREAM
  67 channel_init(VCHANNEL * channel, uint32 length)
  68 {
  69         STREAM s;
  70
  71         s = sec_init(/*g_encryption ? SEC_ENCRYPT :*/ 0, length + 8);
  72         s_push_layer(s, channel_hdr, 8);
  73         return s;
  74 }
  75
  76 void
  77 channel_send(STREAM s, VCHANNEL * channel)
  78 {
  79         uint32 length, flags;
  80         uint32 thislength, remaining;
  81         uint8 *data;
  82
  83         /* first fragment sent in-place */
  84         s_pop_layer(s, channel_hdr);
  85         length = s->end - s->p - 8;
  86
  87         DEBUG_CLIPBOARD(("channel_send, length = %d\n", length));
  88
  89         thislength = MIN(length, CHANNEL_CHUNK_LENGTH);
  90 /* Note: In the original clipboard implementation, this number was
  91    1592, not 1600. However, I don't remember the reason and 1600 seems
  92    to work so.. This applies only to *this* length, not the length of
  93    continuation or ending packets. */
  94         remaining = length - thislength;
  95         flags = (remaining == 0) ? CHANNEL_FLAG_FIRST | CHANNEL_FLAG_LAST : CHANNEL_FLAG_FIRST;
  96         if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
  97                 flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
  98
  99         out_uint32_le(s, length);
 100         out_uint32_le(s, flags);
 101         data = s->end = s->p + thislength;
 102         DEBUG_CLIPBOARD(("Sending %d bytes with FLAG_FIRST\n", thislength));
 103         sec_send_to_channel(s, /*g_encryption ? SEC_ENCRYPT :*/ 0, channel->mcs_id);
 104
 105         /* subsequent segments copied (otherwise would have to generate headers backwards) */
 106         while (remaining > 0)
 107         {
 108                 thislength = MIN(remaining, CHANNEL_CHUNK_LENGTH);
 109                 remaining -= thislength;
 110                 flags = (remaining == 0) ? CHANNEL_FLAG_LAST : 0;
 111                 if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
 112                         flags |= CHANNEL_FLAG_SHOW_PROTOCOL;
 113
 114                 DEBUG_CLIPBOARD(("Sending %d bytes with flags %d\n", thislength, flags));
 115
 116                 s = sec_init(/*g_encryption ? SEC_ENCRYPT : */0, thislength + 8);
 117                 out_uint32_le(s, length);
 118                 out_uint32_le(s, flags);
 119                 out_uint8p(s, data, thislength);
 120                 s_mark_end(s);
 121                 sec_send_to_channel(s, /*g_encryption ? SEC_ENCRYPT : */0, channel->mcs_id);
 122
 123                 data += thislength;
 124         }
 125 }
 126
 127 void
 128 channel_process(STREAM s, uint16 mcs_channel)
 129 {
 130         uint32 length, flags;
 131         uint32 thislength;
 132         VCHANNEL *channel = NULL;
 133         unsigned int i;
 134         STREAM in;
 135
 136         for (i = 0; i < g_num_channels; i++)
 137         {
 138                 channel = &g_channels[i];
 139                 if (channel->mcs_id == mcs_channel)
 140                         break;
 141         }
 142
 143         if (i >= g_num_channels)
 144                 return;
 145
 146         in_uint32_le(s, length);
 147         in_uint32_le(s, flags);
 148         if ((flags & CHANNEL_FLAG_FIRST) && (flags & CHANNEL_FLAG_LAST))
 149         {
 150                 /* single fragment - pass straight up */
 151                 channel->process(s);
 152         }
 153         else
 154         {
 155                 /* add fragment to defragmentation buffer */
 156                 in = &channel->in;
 157                 if (flags & CHANNEL_FLAG_FIRST)
 158                 {
 159                         if (length > in->size)
 160                         {
 161                                 in->data = xrealloc(in->data, length);
 162                                 in->size = length;
 163                         }
 164                         in->p = in->data;
 165                 }
 166
 167                 thislength = MIN(s->end - s->p, in->data + in->size - in->p);
 168                 memcpy(in->p, s->p, thislength);
 169                 in->p += thislength;
 170
 171                 if (flags & CHANNEL_FLAG_LAST)
 172                 {
 173                         in->end = in->p;
 174                         in->p = in->data;
 175                         channel->process(in);
 176                 }
 177         }
 178 }