rdesktop/trunk/mcs.c

/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Protocol services - Multipoint Communications Service
   Copyright (C) Matthew Chapman 1999-2002
   
   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"

uint16 g_mcs_userid;
extern BOOL use_rdp5;

/* Parse an ASN.1 BER header */
static BOOL
ber_parse_header(STREAM s, int tagval, int *length)
{
        int tag, len;

        if (tagval > 0xff)
        {
                in_uint16_be(s, tag);
        }
        else
        {
        in_uint8(s, tag)}

        if (tag != tagval)
        {
                error("expected tag %d, got %d\n", tagval, tag);
                return False;
        }

        in_uint8(s, len);

        if (len & 0x80)
        {
                len &= ~0x80;
                *length = 0;
                while (len--)
                        next_be(s, *length);
        }
        else
                *length = len;

        return s_check(s);
}

/* Output an ASN.1 BER header */
static void
ber_out_header(STREAM s, int tagval, int length)
{
        if (tagval > 0xff)
        {
                out_uint16_be(s, tagval);
        }
        else
        {
                out_uint8(s, tagval);
        }

        if (length >= 0x80)
        {
                out_uint8(s, 0x82);
                out_uint16_be(s, length);
        }
        else
                out_uint8(s, length);
}

/* Output an ASN.1 BER integer */
static void
ber_out_integer(STREAM s, int value)
{
        ber_out_header(s, BER_TAG_INTEGER, 2);
        out_uint16_be(s, value);
}

/* Output a DOMAIN_PARAMS structure (ASN.1 BER) */
static void
mcs_out_domain_params(STREAM s, int max_channels, int max_users, int max_tokens, int max_pdusize)
{
        ber_out_header(s, MCS_TAG_DOMAIN_PARAMS, 32);
        ber_out_integer(s, max_channels);
        ber_out_integer(s, max_users);
        ber_out_integer(s, max_tokens);
        ber_out_integer(s, 1);  /* num_priorities */
        ber_out_integer(s, 0);  /* min_throughput */
        ber_out_integer(s, 1);  /* max_height */
        ber_out_integer(s, max_pdusize);
        ber_out_integer(s, 2);  /* ver_protocol */
}

/* Parse a DOMAIN_PARAMS structure (ASN.1 BER) */
static BOOL
mcs_parse_domain_params(STREAM s)
{
        int length;

        ber_parse_header(s, MCS_TAG_DOMAIN_PARAMS, &length);
        in_uint8s(s, length);

        return s_check(s);
}

/* Send an MCS_CONNECT_INITIAL message (ASN.1 BER) */
static void
mcs_send_connect_initial(STREAM mcs_data)
{
        int datalen = mcs_data->end - mcs_data->data;
        int length = 9 + 3 * 34 + 4 + datalen;
        STREAM s;

        s = iso_init(length + 5);

        ber_out_header(s, MCS_CONNECT_INITIAL, length);
        ber_out_header(s, BER_TAG_OCTET_STRING, 1);     /* calling domain */
        out_uint8(s, 1);
        ber_out_header(s, BER_TAG_OCTET_STRING, 1);     /* called domain */
        out_uint8(s, 1);

        ber_out_header(s, BER_TAG_BOOLEAN, 1);
        out_uint8(s, 0xff);     /* upward flag */

        mcs_out_domain_params(s, 34, 2, 0, 0xffff);     /* target params */
        mcs_out_domain_params(s, 1, 1, 1, 0x420);       /* min params */
        mcs_out_domain_params(s, 0xffff, 0xfc17, 0xffff, 0xffff);       /* max params */

        ber_out_header(s, BER_TAG_OCTET_STRING, datalen);
        out_uint8p(s, mcs_data->data, datalen);

        s_mark_end(s);
        iso_send(s);
}

/* Expect a MCS_CONNECT_RESPONSE message (ASN.1 BER) */
static BOOL
mcs_recv_connect_response(STREAM mcs_data)
{
        uint8 result;
        int length;
        STREAM s;

        s = iso_recv();
        if (s == NULL)
                return False;

        ber_parse_header(s, MCS_CONNECT_RESPONSE, &length);

        ber_parse_header(s, BER_TAG_RESULT, &length);
        in_uint8(s, result);
        if (result != 0)
        {
                error("MCS connect: %d\n", result);
                return False;
        }

        ber_parse_header(s, BER_TAG_INTEGER, &length);
        in_uint8s(s, length);   /* connect id */
        mcs_parse_domain_params(s);

        ber_parse_header(s, BER_TAG_OCTET_STRING, &length);

        sec_process_mcs_data(s);
        /*
           if (length > mcs_data->size)
           {
           error("MCS data length %d, expected %d\n", length,
           mcs_data->size);
           length = mcs_data->size;
           }

           in_uint8a(s, mcs_data->data, length);
           mcs_data->p = mcs_data->data;
           mcs_data->end = mcs_data->data + length;
         */
        return s_check_end(s);
}

/* Send an EDrq message (ASN.1 PER) */
static void
mcs_send_edrq(void)
{
        STREAM s;

        s = iso_init(5);

        out_uint8(s, (MCS_EDRQ << 2));
        out_uint16_be(s, 1);    /* height */
        out_uint16_be(s, 1);    /* interval */

        s_mark_end(s);
        iso_send(s);
}

/* Send an AUrq message (ASN.1 PER) */
static void
mcs_send_aurq(void)
{
        STREAM s;

        s = iso_init(1);

        out_uint8(s, (MCS_AURQ << 2));

        s_mark_end(s);
        iso_send(s);
}

/* Expect a AUcf message (ASN.1 PER) */
static BOOL
mcs_recv_aucf(uint16 * mcs_userid)
{
        uint8 opcode, result;
        STREAM s;

        s = iso_recv();
        if (s == NULL)
                return False;

        in_uint8(s, opcode);
        if ((opcode >> 2) != MCS_AUCF)
        {
                error("expected AUcf, got %d\n", opcode);
                return False;
        }

        in_uint8(s, result);
        if (result != 0)
        {
                error("AUrq: %d\n", result);
                return False;
        }

        if (opcode & 2)
                in_uint16_be(s, *mcs_userid);

        return s_check_end(s);
}

/* Send a CJrq message (ASN.1 PER) */
static void
mcs_send_cjrq(uint16 chanid)
{
        STREAM s;

        s = iso_init(5);

        out_uint8(s, (MCS_CJRQ << 2));
        out_uint16_be(s, g_mcs_userid);
        out_uint16_be(s, chanid);

        s_mark_end(s);
        iso_send(s);
}

/* Expect a CJcf message (ASN.1 PER) */
static BOOL
mcs_recv_cjcf(void)
{
        uint8 opcode, result;
        STREAM s;

        s = iso_recv();
        if (s == NULL)
                return False;

        in_uint8(s, opcode);
        if ((opcode >> 2) != MCS_CJCF)
        {
                error("expected CJcf, got %d\n", opcode);
                return False;
        }

        in_uint8(s, result);
        if (result != 0)
        {
                error("CJrq: %d\n", result);
                return False;
        }

        in_uint8s(s, 4);        /* mcs_userid, req_chanid */
        if (opcode & 2)
                in_uint8s(s, 2);        /* join_chanid */

        return s_check_end(s);
}

/* Initialise an MCS transport data packet */
STREAM
mcs_init(int length)
{
        STREAM s;

        s = iso_init(length + 8);
        s_push_layer(s, mcs_hdr, 8);

        return s;
}

/* Send an MCS transport data packet */
void
mcs_send(STREAM s)
{
        uint16 length;

        s_pop_layer(s, mcs_hdr);
        length = s->end - s->p - 8;
        length |= 0x8000;

        out_uint8(s, (MCS_SDRQ << 2));
        out_uint16_be(s, g_mcs_userid);
        out_uint16_be(s, MCS_GLOBAL_CHANNEL);
        out_uint8(s, 0x70);     /* flags */
        out_uint16_be(s, length);

        iso_send(s);
}

/* Receive an MCS transport data packet */
STREAM
mcs_recv(uint16 * channel)
{
        uint8 opcode, appid, length;
        STREAM s;

        s = iso_recv();
        if (s == NULL)
                return NULL;

        in_uint8(s, opcode);
        appid = opcode >> 2;
        if (appid != MCS_SDIN)
        {
                if (appid != MCS_DPUM)
                {
                        error("expected data, got %d\n", opcode);
                }
                return NULL;
        }

        in_uint8s(s, 2);        /* userid */
        in_uint16_be(s, *channel);
        in_uint8s(s, 1);        /* flags */
        in_uint8(s, length);
        if (length & 0x80)
                in_uint8s(s, 1);        /* second byte of length */

        return s;
}

/* Establish a connection up to the MCS layer */
BOOL
mcs_connect(char *server, STREAM mcs_data, char *username)
{
        if (!iso_connect(server, username))
                return False;

        mcs_send_connect_initial(mcs_data);
        if (!mcs_recv_connect_response(mcs_data))
                goto error;

        mcs_send_edrq();

        mcs_send_aurq();
        if (!mcs_recv_aucf(&g_mcs_userid))
                goto error;

        mcs_send_cjrq(g_mcs_userid + 1001);
        if (!mcs_recv_cjcf())
                goto error;

        mcs_send_cjrq(MCS_GLOBAL_CHANNEL);
        if (!mcs_recv_cjcf())
                goto error;

        if (use_rdp5)
        {
                /* Note: If we send this cjrq after telling the server we support RDP4 only,
                   the server won't respond with a cjcf and we will hang. */
                mcs_send_cjrq(MCS_GLOBAL_CHANNEL + 1);  /* hack - clipboard */
                if (!mcs_recv_cjcf())
                        goto error;
        }

        return True;

      error:
        iso_disconnect();
        return False;
}

/* Disconnect from the MCS layer */
void
mcs_disconnect(void)
{
        iso_disconnect();
}
1	forsberg	348	/* -- c-basic-offset: 8 --
2	matty	3	rdesktop: A Remote Desktop Protocol client.
3			Protocol services - Multipoint Communications Service
4	matthewc	207	Copyright (C) Matthew Chapman 1999-2002
5	matty	3
6			This program is free software; you can redistribute it and/or modify
7			it under the terms of the GNU General Public License as published by
8			the Free Software Foundation; either version 2 of the License, or
9			(at your option) any later version.
10
11			This program is distributed in the hope that it will be useful,
12			but WITHOUT ANY WARRANTY; without even the implied warranty of
13			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			GNU General Public License for more details.
15
16			You should have received a copy of the GNU General Public License
17			along with this program; if not, write to the Free Software
18			Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19			*/
20
21	matty	10	#include "rdesktop.h"
22	matty	3
23	jsorg71	381	uint16 g_mcs_userid;
24	forsberg	348	extern BOOL use_rdp5;
25	matty	10
26			/* Parse an ASN.1 BER header */
27	matty	25	static BOOL
28			ber_parse_header(STREAM s, int tagval, int *length)
29	matty	3	{
30	matty	10	int tag, len;
31	matty	3
32	matty	10	if (tagval > 0xff)
33	matty	3	{
34	matty	10	in_uint16_be(s, tag);
35	matty	3	}
36	matty	10	else
37	matty	3	{
38	matty	24	in_uint8(s, tag)}
39	matty	3
40	matty	10	if (tag != tagval)
41	matty	3	{
42	matty	30	error("expected tag %d, got %d\n", tagval, tag);
43	matty	10	return False;
44	matty	3	}
45
46	matty	10	in_uint8(s, len);
47	matty	3
48	matty	10	if (len & 0x80)
49	matty	3	{
50	matty	10	len &= ~0x80;
51			*length = 0;
52			while (len--)
53			next_be(s, *length);
54	matty	3	}
55	matty	24	else
56			*length = len;
57	matty	3
58	matty	10	return s_check(s);
59	matty	3	}
60
61	matty	10	/* Output an ASN.1 BER header */
62	matty	25	static void
63			ber_out_header(STREAM s, int tagval, int length)
64	matty	3	{
65	matty	10	if (tagval > 0xff)
66	matty	3	{
67	matty	10	out_uint16_be(s, tagval);
68	matty	3	}
69	matty	10	else
70			{
71			out_uint8(s, tagval);
72			}
73	matty	3
74	matty	10	if (length >= 0x80)
75	matty	3	{
76	matty	10	out_uint8(s, 0x82);
77			out_uint16_be(s, length);
78	matty	3	}
79	matty	24	else
80			out_uint8(s, length);
81	matty	3	}
82
83	matty	10	/* Output an ASN.1 BER integer */
84	matty	25	static void
85			ber_out_integer(STREAM s, int value)
86	matty	3	{
87	matty	10	ber_out_header(s, BER_TAG_INTEGER, 2);
88			out_uint16_be(s, value);
89	matty	3	}
90
91	matty	10	/* Output a DOMAIN_PARAMS structure (ASN.1 BER) */
92	matty	25	static void
93	astrand	82	mcs_out_domain_params(STREAM s, int max_channels, int max_users, int max_tokens, int max_pdusize)
94	matty	3	{
95	matty	10	ber_out_header(s, MCS_TAG_DOMAIN_PARAMS, 32);
96			ber_out_integer(s, max_channels);
97			ber_out_integer(s, max_users);
98			ber_out_integer(s, max_tokens);
99	matty	24	ber_out_integer(s, 1); /* num_priorities */
100			ber_out_integer(s, 0); /* min_throughput */
101			ber_out_integer(s, 1); /* max_height */
102	matty	10	ber_out_integer(s, max_pdusize);
103	matty	24	ber_out_integer(s, 2); /* ver_protocol */
104	matty	3	}
105
106	matty	10	/* Parse a DOMAIN_PARAMS structure (ASN.1 BER) */
107	matty	25	static BOOL
108			mcs_parse_domain_params(STREAM s)
109	matty	3	{
110	matty	10	int length;
111	matty	3
112	matty	10	ber_parse_header(s, MCS_TAG_DOMAIN_PARAMS, &length);
113			in_uint8s(s, length);
114
115			return s_check(s);
116	matty	3	}
117
118	matty	10	/* Send an MCS_CONNECT_INITIAL message (ASN.1 BER) */
119	matty	25	static void
120			mcs_send_connect_initial(STREAM mcs_data)
121	matty	3	{
122	matty	10	int datalen = mcs_data->end - mcs_data->data;
123	forsberg	348	int length = 9 + 3 * 34 + 4 + datalen;
124	matty	10	STREAM s;
125	matty	3
126	matty	10	s = iso_init(length + 5);
127	matty	3
128	matty	10	ber_out_header(s, MCS_CONNECT_INITIAL, length);
129	forsberg	348	ber_out_header(s, BER_TAG_OCTET_STRING, 1); /* calling domain */
130			out_uint8(s, 1);
131			ber_out_header(s, BER_TAG_OCTET_STRING, 1); /* called domain */
132			out_uint8(s, 1);
133	matty	3
134	matty	10	ber_out_header(s, BER_TAG_BOOLEAN, 1);
135	matty	24	out_uint8(s, 0xff); /* upward flag */
136	matty	3
137	forsberg	348	mcs_out_domain_params(s, 34, 2, 0, 0xffff); /* target params */
138	matty	24	mcs_out_domain_params(s, 1, 1, 1, 0x420); /* min params */
139			mcs_out_domain_params(s, 0xffff, 0xfc17, 0xffff, 0xffff); /* max params */
140	matty	3
141	matty	10	ber_out_header(s, BER_TAG_OCTET_STRING, datalen);
142			out_uint8p(s, mcs_data->data, datalen);
143	matty	3
144	matty	10	s_mark_end(s);
145			iso_send(s);
146	matty	3	}
147
148	matty	10	/* Expect a MCS_CONNECT_RESPONSE message (ASN.1 BER) */
149	matty	25	static BOOL
150			mcs_recv_connect_response(STREAM mcs_data)
151	matty	3	{
152	matty	10	uint8 result;
153			int length;
154			STREAM s;
155	matty	3
156	matty	10	s = iso_recv();
157			if (s == NULL)
158	matty	7	return False;
159
160	matty	10	ber_parse_header(s, MCS_CONNECT_RESPONSE, &length);
161	matty	3
162	matty	10	ber_parse_header(s, BER_TAG_RESULT, &length);
163			in_uint8(s, result);
164			if (result != 0)
165	matty	7	{
166	matty	30	error("MCS connect: %d\n", result);
167	matty	3	return False;
168			}
169
170	matty	10	ber_parse_header(s, BER_TAG_INTEGER, &length);
171	matty	24	in_uint8s(s, length); /* connect id */
172	matty	10	mcs_parse_domain_params(s);
173
174			ber_parse_header(s, BER_TAG_OCTET_STRING, &length);
175	matty	3
176	forsberg	348	sec_process_mcs_data(s);
177			/*
178			if (length > mcs_data->size)
179			{
180	jsorg71	381	error("MCS data length %d, expected %d\n", length,
181	forsberg	348	mcs_data->size);
182			length = mcs_data->size;
183			}
184	matty	3
185	forsberg	348	in_uint8a(s, mcs_data->data, length);
186			mcs_data->p = mcs_data->data;
187			mcs_data->end = mcs_data->data + length;
188			*/
189	matty	10	return s_check_end(s);
190	matty	3	}
191
192	matty	10	/* Send an EDrq message (ASN.1 PER) */
193	matty	25	static void
194	matthewc	192	mcs_send_edrq(void)
195	matty	3	{
196	matty	10	STREAM s;
197	matty	3
198	matty	10	s = iso_init(5);
199	matty	3
200	matty	10	out_uint8(s, (MCS_EDRQ << 2));
201	matty	24	out_uint16_be(s, 1); /* height */
202			out_uint16_be(s, 1); /* interval */
203	matty	3
204	matty	10	s_mark_end(s);
205			iso_send(s);
206	matty	3	}
207
208	matty	10	/* Send an AUrq message (ASN.1 PER) */
209	matty	25	static void
210	matthewc	192	mcs_send_aurq(void)
211	matty	3	{
212	matty	10	STREAM s;
213	matty	3
214	matty	10	s = iso_init(1);
215	matty	3
216	matty	10	out_uint8(s, (MCS_AURQ << 2));
217	matty	3
218	matty	10	s_mark_end(s);
219			iso_send(s);
220	matty	3	}
221
222	matty	10	/* Expect a AUcf message (ASN.1 PER) */
223	matty	25	static BOOL
224	astrand	64	mcs_recv_aucf(uint16 * mcs_userid)
225	matty	3	{
226	matty	10	uint8 opcode, result;
227			STREAM s;
228	matty	3
229	matty	10	s = iso_recv();
230			if (s == NULL)
231	matty	3	return False;
232
233	matty	10	in_uint8(s, opcode);
234			if ((opcode >> 2) != MCS_AUCF)
235	matty	3	{
236	matty	30	error("expected AUcf, got %d\n", opcode);
237	matty	3	return False;
238			}
239
240	matty	10	in_uint8(s, result);
241			if (result != 0)
242			{
243	matty	30	error("AUrq: %d\n", result);
244	matty	10	return False;
245			}
246	matty	3
247	matty	10	if (opcode & 2)
248			in_uint16_be(s, *mcs_userid);
249	matty	3
250	matty	10	return s_check_end(s);
251	matty	3	}
252
253	matty	10	/* Send a CJrq message (ASN.1 PER) */
254	matty	25	static void
255			mcs_send_cjrq(uint16 chanid)
256	matty	3	{
257	matty	10	STREAM s;
258	matty	3
259	matty	10	s = iso_init(5);
260	matty	3
261	matty	10	out_uint8(s, (MCS_CJRQ << 2));
262	jsorg71	381	out_uint16_be(s, g_mcs_userid);
263	matty	10	out_uint16_be(s, chanid);
264
265			s_mark_end(s);
266			iso_send(s);
267	matty	3	}
268
269	matty	10	/* Expect a CJcf message (ASN.1 PER) */
270	matty	25	static BOOL
271	matthewc	192	mcs_recv_cjcf(void)
272	matty	3	{
273	matty	10	uint8 opcode, result;
274			STREAM s;
275	matty	3
276	matty	10	s = iso_recv();
277			if (s == NULL)
278			return False;
279	matty	3
280	matty	10	in_uint8(s, opcode);
281			if ((opcode >> 2) != MCS_CJCF)
282			{
283	matty	30	error("expected CJcf, got %d\n", opcode);
284	matty	10	return False;
285			}
286	matty	3
287	matty	10	in_uint8(s, result);
288			if (result != 0)
289	matty	3	{
290	matty	30	error("CJrq: %d\n", result);
291	matty	3	return False;
292			}
293
294	matty	24	in_uint8s(s, 4); /* mcs_userid, req_chanid */
295	matty	10	if (opcode & 2)
296	matty	24	in_uint8s(s, 2); /* join_chanid */
297	matty	3
298	matty	10	return s_check_end(s);
299	matty	3	}
300
301	matty	10	/* Initialise an MCS transport data packet */
302	matty	25	STREAM
303			mcs_init(int length)
304	matty	3	{
305	matty	10	STREAM s;
306	matty	3
307	matty	10	s = iso_init(length + 8);
308			s_push_layer(s, mcs_hdr, 8);
309	matty	3
310	matty	10	return s;
311	matty	3	}
312
313	matty	10	/* Send an MCS transport data packet */
314	matty	25	void
315			mcs_send(STREAM s)
316	matty	3	{
317	matty	10	uint16 length;
318	matty	3
319	matty	10	s_pop_layer(s, mcs_hdr);
320			length = s->end - s->p - 8;
321			length \|= 0x8000;
322	matty	3
323	matty	10	out_uint8(s, (MCS_SDRQ << 2));
324	jsorg71	381	out_uint16_be(s, g_mcs_userid);
325	matty	10	out_uint16_be(s, MCS_GLOBAL_CHANNEL);
326	matty	24	out_uint8(s, 0x70); /* flags */
327	matty	10	out_uint16_be(s, length);
328	matty	3
329	matty	10	iso_send(s);
330	matty	3	}
331
332	matty	10	/* Receive an MCS transport data packet */
333	matty	25	STREAM
334	forsberg	348	mcs_recv(uint16 * channel)
335	matty	3	{
336	matty	10	uint8 opcode, appid, length;
337			STREAM s;
338	matty	3
339	matty	10	s = iso_recv();
340			if (s == NULL)
341			return NULL;
342
343			in_uint8(s, opcode);
344			appid = opcode >> 2;
345			if (appid != MCS_SDIN)
346	matty	3	{
347	matty	10	if (appid != MCS_DPUM)
348			{
349	matty	30	error("expected data, got %d\n", opcode);
350	matty	10	}
351			return NULL;
352	matty	3	}
353
354	forsberg	348	in_uint8s(s, 2); /* userid */
355			in_uint16_be(s, *channel);
356			in_uint8s(s, 1); /* flags */
357	matty	10	in_uint8(s, length);
358			if (length & 0x80)
359	matty	24	in_uint8s(s, 1); /* second byte of length */
360	matty	3
361	matty	10	return s;
362	matty	3	}
363
364	matty	10	/* Establish a connection up to the MCS layer */
365	matty	25	BOOL
366	forsberg	348	mcs_connect(char server, STREAM mcs_data, char username)
367	matty	3	{
368	forsberg	348	if (!iso_connect(server, username))
369	matty	3	return False;
370
371	matty	10	mcs_send_connect_initial(mcs_data);
372			if (!mcs_recv_connect_response(mcs_data))
373			goto error;
374	matty	3
375	matty	10	mcs_send_edrq();
376	matty	3
377	matty	10	mcs_send_aurq();
378	jsorg71	381	if (!mcs_recv_aucf(&g_mcs_userid))
379	matty	10	goto error;
380	matty	3
381	jsorg71	381	mcs_send_cjrq(g_mcs_userid + 1001);
382	matty	10	if (!mcs_recv_cjcf())
383			goto error;
384	matty	3
385	matty	10	mcs_send_cjrq(MCS_GLOBAL_CHANNEL);
386			if (!mcs_recv_cjcf())
387			goto error;
388	matty	3
389	forsberg	348	if (use_rdp5)
390			{
391	jsorg71	381	/* Note: If we send this cjrq after telling the server we support RDP4 only,
392	forsberg	348	the server won't respond with a cjcf and we will hang. */
393			mcs_send_cjrq(MCS_GLOBAL_CHANNEL + 1); /* hack - clipboard */
394			if (!mcs_recv_cjcf())
395			goto error;
396			}
397
398	matty	10	return True;
399	matty	7
400	matty	24	error:
401	matty	10	iso_disconnect();
402			return False;
403	matty	3	}
404	matty	7
405	matty	10	/* Disconnect from the MCS layer */
406	matty	25	void
407	matthewc	192	mcs_disconnect(void)
408	matty	10	{
409			iso_disconnect();
410			}