mcs.c

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/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Protocol services - Multipoint Communications Service
   Copyright (C) Matthew Chapman 1999-2005

   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.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include <precomp.h>

uint16 g_mcs_userid;
extern VCHANNEL g_channels[];
extern unsigned int g_num_channels;

/* 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(NULL);
    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(NULL);
    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;

    DEBUG_RDP5(("Sending CJRQ for channel #%d\n", chanid));

    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(NULL);
    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 to a specific channel */
void
mcs_send_to_channel(STREAM s, uint16 channel)
{
    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, channel);
    out_uint8(s, 0x70); /* flags */
    out_uint16_be(s, length);

    iso_send(s);
}

/* Send an MCS transport data packet to the global channel */
void
mcs_send(STREAM s)
{
    mcs_send_to_channel(s, MCS_GLOBAL_CHANNEL);
}

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

    s = iso_recv(rdpver);
    if (s == NULL)
        return NULL;
    if (rdpver != NULL)
        if (*rdpver != 3)
            return s;
    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)
{
    unsigned int i;

    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((uint16) (g_mcs_userid + MCS_USERCHANNEL_BASE));

    if (!mcs_recv_cjcf())
        goto error;

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

    for (i = 0; i < g_num_channels; i++)
    {
        mcs_send_cjrq(g_channels[i].mcs_id);
        if (!mcs_recv_cjcf())
            goto error;
    }
    return True;

      error:
    iso_disconnect();
    return False;
}

/* Establish a connection up to the MCS layer */
BOOL
mcs_reconnect(char *server, STREAM mcs_data)
{
    unsigned int i;

    if (!iso_reconnect(server))
        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((uint16) (g_mcs_userid + MCS_USERCHANNEL_BASE));

    if (!mcs_recv_cjcf())
        goto error;

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

    for (i = 0; i < g_num_channels; i++)
    {
        mcs_send_cjrq(g_channels[i].mcs_id);
        if (!mcs_recv_cjcf())
            goto error;
    }
    return True;

      error:
    iso_disconnect();
    return False;
}

/* Disconnect from the MCS layer */
void
mcs_disconnect(void)
{
    iso_disconnect();
}

/* reset the state of the mcs layer */
void
mcs_reset_state(void)
{
    g_mcs_userid = 0;
    iso_reset_state();
}