rdesktop/trunk/channels.c

/* -*- 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 2003-2008

   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      0x10

extern 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;
}

STREAM
channel_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;
}

void
channel_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
}

void
channel_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);
                }
        }
}
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 2003-2008
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 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 RD_BOOL g_use_rdp5;
31	extern RD_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	#ifdef WITH_SCARD
87	scard_lock(SCARD_LOCK_CHANNEL);
88	#endif
89
90	/* first fragment sent in-place */
91	s_pop_layer(s, channel_hdr);
92	length = s->end - s->p - 8;
93
94	DEBUG_CHANNEL(("channel_send, length = %d\n", length));
95
96	thislength = MIN(length, CHANNEL_CHUNK_LENGTH);
97	/* Note: In the original clipboard implementation, this number was
98	1592, not 1600. However, I don't remember the reason and 1600 seems
99	to work so.. This applies only to this length, not the length of
100	continuation or ending packets. */
101	remaining = length - thislength;
102	flags = (remaining == 0) ? CHANNEL_FLAG_FIRST \| CHANNEL_FLAG_LAST : CHANNEL_FLAG_FIRST;
103	if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
104	flags \|= CHANNEL_FLAG_SHOW_PROTOCOL;
105
106	out_uint32_le(s, length);
107	out_uint32_le(s, flags);
108	data = s->end = s->p + thislength;
109	DEBUG_CHANNEL(("Sending %d bytes with FLAG_FIRST\n", thislength));
110	sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
111
112	/* subsequent segments copied (otherwise would have to generate headers backwards) */
113	while (remaining > 0)
114	{
115	thislength = MIN(remaining, CHANNEL_CHUNK_LENGTH);
116	remaining -= thislength;
117	flags = (remaining == 0) ? CHANNEL_FLAG_LAST : 0;
118	if (channel->flags & CHANNEL_OPTION_SHOW_PROTOCOL)
119	flags \|= CHANNEL_FLAG_SHOW_PROTOCOL;
120
121	DEBUG_CHANNEL(("Sending %d bytes with flags %d\n", thislength, flags));
122
123	s = sec_init(g_encryption ? SEC_ENCRYPT : 0, thislength + 8);
124	out_uint32_le(s, length);
125	out_uint32_le(s, flags);
126	out_uint8p(s, data, thislength);
127	s_mark_end(s);
128	sec_send_to_channel(s, g_encryption ? SEC_ENCRYPT : 0, channel->mcs_id);
129
130	data += thislength;
131	}
132
133	#ifdef WITH_SCARD
134	scard_unlock(SCARD_LOCK_CHANNEL);
135	#endif
136	}
137
138	void
139	channel_process(STREAM s, uint16 mcs_channel)
140	{
141	uint32 length, flags;
142	uint32 thislength;
143	VCHANNEL *channel = NULL;
144	unsigned int i;
145	STREAM in;
146
147	for (i = 0; i < g_num_channels; i++)
148	{
149	channel = &g_channels[i];
150	if (channel->mcs_id == mcs_channel)
151	break;
152	}
153
154	if (i >= g_num_channels)
155	return;
156
157	in_uint32_le(s, length);
158	in_uint32_le(s, flags);
159	if ((flags & CHANNEL_FLAG_FIRST) && (flags & CHANNEL_FLAG_LAST))
160	{
161	/* single fragment - pass straight up */
162	channel->process(s);
163	}
164	else
165	{
166	/* add fragment to defragmentation buffer */
167	in = &channel->in;
168	if (flags & CHANNEL_FLAG_FIRST)
169	{
170	if (length > in->size)
171	{
172	in->data = (uint8 *) xrealloc(in->data, length);
173	in->size = length;
174	}
175	in->p = in->data;
176	}
177
178	thislength = MIN(s->end - s->p, in->data + in->size - in->p);
179	memcpy(in->p, s->p, thislength);
180	in->p += thislength;
181
182	if (flags & CHANNEL_FLAG_LAST)
183	{
184	in->end = in->p;
185	in->p = in->data;
186	channel->process(in);
187	}
188	}
189	}