/**
 * xrdp: A Remote Desktop Protocol server.
 *
 * Copyright (C) Jay Sorg 2004-2013
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * librdp mcs layer
 */

#include "rdp.h"
#include "log.h"

/*****************************************************************************/
struct rdp_mcs *APP_CC
rdp_mcs_create(struct rdp_sec *owner,
               struct stream *client_mcs_data,
               struct stream *server_mcs_data)
{
    struct rdp_mcs *self;

    self = (struct rdp_mcs *)g_malloc(sizeof(struct rdp_mcs), 1);
    self->sec_layer = owner;
    self->userid = 1;
    self->client_mcs_data = client_mcs_data;
    self->server_mcs_data = server_mcs_data;
    self->iso_layer = rdp_iso_create(self);
    return self;
}

/*****************************************************************************/
void APP_CC
rdp_mcs_delete(struct rdp_mcs *self)
{
    if (self == 0)
    {
        return;
    }

    rdp_iso_delete(self->iso_layer);
    g_free(self);
}

/*****************************************************************************/
/* returns error */
int APP_CC
rdp_mcs_recv(struct rdp_mcs *self, struct stream *s, int *chan)
{
    int appid;
    int opcode;
    int len;

    DEBUG(("  in rdp_mcs_recv"));

    if (rdp_iso_recv(self->iso_layer, s) != 0)
    {
        return 1;
    }

    in_uint8(s, opcode);
    appid = opcode >> 2;

    if (appid != MCS_SDIN)
    {
        DEBUG(("  out rdp_mcs_recv error"));
        return 1;
    }

    in_uint8s(s, 2);
    in_uint16_be(s, *chan);
    in_uint8s(s, 1);
    in_uint8(s, len);

    if (len & 0x80)
    {
        in_uint8s(s, 1);
    }

    DEBUG(("  out rdp_mcs_recv"));
    return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_ber_out_header(struct rdp_mcs *self, struct stream *s,
                       int tag_val, int len)
{
    if (tag_val > 0xff)
    {
        out_uint16_be(s, tag_val);
    }
    else
    {
        out_uint8(s, tag_val);
    }

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

    return 0;
}

#if 0
/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_ber_out_int8(struct rdp_mcs *self, struct stream *s, int value)
{
    rdp_mcs_ber_out_header(self, s, BER_TAG_INTEGER, 1);
    out_uint8(s, value);
    return 0;
}
#endif

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_ber_out_int16(struct rdp_mcs *self, struct stream *s, int value)
{
    rdp_mcs_ber_out_header(self, s, BER_TAG_INTEGER, 2);
    out_uint8(s, (value >> 8));
    out_uint8(s, value);
    return 0;
}

#if 0
/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_ber_out_int24(struct rdp_mcs *self, struct stream *s, int value)
{
    rdp_mcs_ber_out_header(self, s, BER_TAG_INTEGER, 3);
    out_uint8(s, (value >> 16));
    out_uint8(s, (value >> 8));
    out_uint8(s, value);
    return 0;
}
#endif

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_out_domain_params(struct rdp_mcs *self, struct stream *s,
                          int max_channels,
                          int max_users, int max_tokens,
                          int max_pdu_size)
{
    rdp_mcs_ber_out_header(self, s, MCS_TAG_DOMAIN_PARAMS, 32);
    rdp_mcs_ber_out_int16(self, s, max_channels);
    rdp_mcs_ber_out_int16(self, s, max_users);
    rdp_mcs_ber_out_int16(self, s, max_tokens);
    rdp_mcs_ber_out_int16(self, s, 1);
    rdp_mcs_ber_out_int16(self, s, 0);
    rdp_mcs_ber_out_int16(self, s, 1);
    rdp_mcs_ber_out_int16(self, s, max_pdu_size);
    rdp_mcs_ber_out_int16(self, s, 2);
    return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_send_connection_initial(struct rdp_mcs *self)
{
    int data_len;
    int len;
    struct stream *s;

    make_stream(s);
    init_stream(s, 8192);
    data_len = self->client_mcs_data->end - self->client_mcs_data->data;
    len = 7 + 3 * 34 + 4 + data_len;

    if (rdp_iso_init(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    rdp_mcs_ber_out_header(self, s, MCS_CONNECT_INITIAL, len);
    rdp_mcs_ber_out_header(self, s, BER_TAG_OCTET_STRING, 0); /* calling domain */
    rdp_mcs_ber_out_header(self, s, BER_TAG_OCTET_STRING, 0); /* called domain */
    rdp_mcs_ber_out_header(self, s, BER_TAG_BOOLEAN, 1);
    out_uint8(s, 0xff); /* upward flag */
    rdp_mcs_out_domain_params(self, s, 2, 2, 0, 0xffff); /* target params */
    rdp_mcs_out_domain_params(self, s, 1, 1, 1, 0x420); /* min params */
    rdp_mcs_out_domain_params(self, s, 0xffff, 0xfc17, 0xffff, 0xffff); /* max params */
    rdp_mcs_ber_out_header(self, s, BER_TAG_OCTET_STRING, data_len);
    out_uint8p(s, self->client_mcs_data->data, data_len);
    s_mark_end(s);

    if (rdp_iso_send(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    free_stream(s);
    return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_ber_parse_header(struct rdp_mcs *self, struct stream *s,
                         int tag_val, int *len)
{
    int tag;
    int l;
    int i;

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

    if (tag != tag_val)
    {
        return 1;
    }

    in_uint8(s, l);

    if (l & 0x80)
    {
        l = l & ~0x80;
        *len = 0;

        while (l > 0)
        {
            in_uint8(s, i);
            *len = (*len << 8) | i;
            l--;
        }
    }
    else
    {
        *len = l;
    }

    if (s_check(s))
    {
        return 0;
    }
    else
    {
        return 1;
    }
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_parse_domain_params(struct rdp_mcs *self, struct stream *s)
{
    int len;

    if (rdp_mcs_ber_parse_header(self, s, MCS_TAG_DOMAIN_PARAMS, &len) != 0)
    {
        return 1;
    }

    in_uint8s(s, len);

    if (s_check(s))
    {
        return 0;
    }
    else
    {
        return 1;
    }
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_recv_connection_response(struct rdp_mcs *self)
{
    int len;
    int res;
    struct stream *s;

    make_stream(s);
    init_stream(s, 8192);

    if (rdp_iso_recv(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    rdp_mcs_ber_parse_header(self, s, MCS_CONNECT_RESPONSE, &len);
    rdp_mcs_ber_parse_header(self, s, BER_TAG_RESULT, &len);
    in_uint8(s, res);

    if (res != 0)
    {
        free_stream(s);
        return 1;
    }

    rdp_mcs_ber_parse_header(self, s, BER_TAG_INTEGER, &len);
    in_uint8s(s, len); /* connect id */
    rdp_mcs_parse_domain_params(self, s);
    rdp_mcs_ber_parse_header(self, s, BER_TAG_OCTET_STRING, &len);

    if (len > self->server_mcs_data->size)
    {
        len = self->server_mcs_data->size;
    }

    in_uint8a(s, self->server_mcs_data->data, len);
    self->server_mcs_data->p = self->server_mcs_data->data;
    self->server_mcs_data->end = self->server_mcs_data->data + len;

    if (s_check_end(s))
    {
        free_stream(s);
        return 0;
    }
    else
    {
        free_stream(s);
        return 1;
    }
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_send_edrq(struct rdp_mcs *self)
{
    struct stream *s;

    make_stream(s);
    init_stream(s, 8192);

    if (rdp_iso_init(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    out_uint8(s, (MCS_EDRQ << 2));
    out_uint16_be(s, 0x100); /* height */
    out_uint16_be(s, 0x100); /* interval */
    s_mark_end(s);

    if (rdp_iso_send(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    free_stream(s);
    return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_send_aurq(struct rdp_mcs *self)
{
    struct stream *s;

    make_stream(s);
    init_stream(s, 8192);

    if (rdp_iso_init(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

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

    if (rdp_iso_send(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    free_stream(s);
    return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_recv_aucf(struct rdp_mcs *self)
{
    int opcode;
    int res;
    struct stream *s;

    make_stream(s);
    init_stream(s, 8192);

    if (rdp_iso_recv(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    in_uint8(s, opcode);

    if ((opcode >> 2) != MCS_AUCF)
    {
        free_stream(s);
        return 1;
    }

    in_uint8(s, res);

    if (res != 0)
    {
        free_stream(s);
        return 1;
    }

    if (opcode & 2)
    {
        in_uint16_be(s, self->userid);
    }

    if (!(s_check_end(s)))
    {
        free_stream(s);
        return 1;
    }

    free_stream(s);
    return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_send_cjrq(struct rdp_mcs *self, int chanid)
{
    struct stream *s;

    make_stream(s);
    init_stream(s, 8192);

    if (rdp_iso_init(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    out_uint8(s, (MCS_CJRQ << 2));
    out_uint16_be(s, self->userid);
    out_uint16_be(s, chanid);
    s_mark_end(s);

    if (rdp_iso_send(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    free_stream(s);
    return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
rdp_mcs_recv_cjcf(struct rdp_mcs *self)
{
    int opcode;
    int res;
    struct stream *s;

    make_stream(s);
    init_stream(s, 8192);

    if (rdp_iso_recv(self->iso_layer, s) != 0)
    {
        free_stream(s);
        return 1;
    }

    in_uint8(s, opcode);

    if ((opcode >> 2) != MCS_CJCF)
    {
        free_stream(s);
        return 1;
    }

    in_uint8(s, res);

    if (res != 0)
    {
        free_stream(s);
        return 1;
    }

    in_uint8s(s, 4); /* mcs_userid, req_chanid */

    if (opcode & 2)
    {
        in_uint8s(s, 2); /* join_chanid */
    }

    if (!(s_check_end(s)))
    {
        free_stream(s);
        return 1;
    }

    free_stream(s);
    return 0;
}

/*****************************************************************************/
/* returns error */
int APP_CC
rdp_mcs_connect(struct rdp_mcs *self, char *ip, char *port)
{
    DEBUG(("  in rdp_mcs_connect"));

    if (rdp_iso_connect(self->iso_layer, ip, port) != 0)
    {
        DEBUG(("  out rdp_mcs_connect error rdp_iso_connect failed"));
        return 1;
    }

    rdp_mcs_send_connection_initial(self);

    if (rdp_mcs_recv_connection_response(self) != 0)
    {
        rdp_iso_disconnect(self->iso_layer);
        DEBUG(("  out rdp_mcs_connect error rdp_mcs_recv_connection_response \
failed"));
        return 1;
    }

    rdp_mcs_send_edrq(self);
    rdp_mcs_send_aurq(self);

    if (rdp_mcs_recv_aucf(self) != 0)
    {
        rdp_iso_disconnect(self->iso_layer);
        DEBUG(("  out rdp_mcs_connect error rdp_mcs_recv_aucf failed"));
        return 1;
    }

    rdp_mcs_send_cjrq(self, self->userid + 1001);

    if (rdp_mcs_recv_cjcf(self) != 0)
    {
        rdp_iso_disconnect(self->iso_layer);
        DEBUG(("  out rdp_mcs_connect error rdp_mcs_recv_cjcf 1 failed"));
        return 1;
    }

    rdp_mcs_send_cjrq(self, MCS_GLOBAL_CHANNEL);

    if (rdp_mcs_recv_cjcf(self) != 0)
    {
        rdp_iso_disconnect(self->iso_layer);
        DEBUG(("  out rdp_mcs_connect error rdp_mcs_recv_cjcf 2 failed"));
        return 1;
    }

    DEBUG(("  out rdp_mcs_connect"));
    return 0;
}

/*****************************************************************************/
/* returns error */
int APP_CC
rdp_mcs_init(struct rdp_mcs *self, struct stream *s)
{
    if (rdp_iso_init(self->iso_layer, s))
        log_message(LOG_LEVEL_ERROR, "rdp_mcs.c: rdp_iso_init() failed");
    s_push_layer(s, mcs_hdr, 8);
    return 0;
}

/*****************************************************************************/
/* returns error */
int APP_CC
rdp_mcs_send(struct rdp_mcs *self, struct stream *s)
{
    int len;

    s_pop_layer(s, mcs_hdr);
    len = (s->end - s->p) - 8;
    len = len | 0x8000;
    out_uint8(s, MCS_SDRQ << 2);
    out_uint16_be(s, self->userid);
    out_uint16_be(s, MCS_GLOBAL_CHANNEL);
    out_uint8(s, 0x70);
    out_uint16_be(s, len);

    if (rdp_iso_send(self->iso_layer, s) != 0)
    {
        return 1;
    }

    return 0;
}