/*
   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.

   Copyright (C) Jay Sorg 2004

   mcs layer

*/

#include "xrdp.h"

/*****************************************************************************/
struct xrdp_mcs* xrdp_mcs_create(struct xrdp_sec* owner)
{
  struct xrdp_mcs* self;

  self = (struct xrdp_mcs*)g_malloc(sizeof(struct xrdp_mcs), 1);
  self->sec_layer = owner;
  self->in_s = owner->in_s;
  self->out_s = owner->out_s;
  self->userid = 1;
  self->chanid = 1001;
  self->client_mcs_data = &owner->client_mcs_data;
  self->server_mcs_data = &owner->server_mcs_data;
  self->iso_layer = xrdp_iso_create(self);
  return self;
}

/*****************************************************************************/
void xrdp_mcs_delete(struct xrdp_mcs* self)
{
  if (self == 0)
    return;
  xrdp_iso_delete(self->iso_layer);
  g_free(self);
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_send_cjcf(struct xrdp_mcs* self, int chanid)
{
  if (xrdp_iso_init(self->iso_layer, 8) != 0)
    return 1;
  out_uint8(self->out_s, (MCS_CJCF << 2) | 2);
  out_uint8(self->out_s, 0);
  out_uint16_be(self->out_s, self->userid);
  out_uint16_be(self->out_s, chanid);
  out_uint16_be(self->out_s, chanid);
  s_mark_end(self->out_s);
  if (xrdp_iso_send(self->iso_layer) != 0)
    return 1;
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_recv(struct xrdp_mcs* self, int* chan)
{
  int appid;
  int opcode;
  int len;

  DEBUG(("  in xrdp_mcs_recv\n\r"));
  while (1)
  {
    if (xrdp_iso_recv(self->iso_layer) != 0)
      return 1;
    in_uint8(self->in_s, opcode);
    appid = opcode >> 2;
    if (appid == MCS_DPUM)
      return 1;
    if (appid == MCS_CJRQ)
    {
      xrdp_mcs_send_cjcf(self, self->userid + MCS_USERCHANNEL_BASE);
      continue;
    }
    break;
  }
  if (appid != MCS_SDRQ)
  {
    DEBUG(("  out xrdp_mcs_recv err got 0x%x need MCS_SDRQ\n\r", appid));
    return 1;
  }
  in_uint8s(self->in_s, 2);
  in_uint16_be(self->in_s, *chan);
  in_uint8s(self->in_s, 1);
  in_uint8(self->in_s, len);
  if (len & 0x80)
    in_uint8s(self->in_s, 1);
  DEBUG(("  out xrdp_mcs_recv\n\r"));
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_ber_parse_header(struct xrdp_mcs* self, int tag_val, int* len)
{
  int tag;
  int l;
  int i;

  if (tag_val > 0xff)
  {
    in_uint16_be(self->in_s, tag);
  }
  else
  {
    in_uint8(self->in_s, tag);
  }
  if (tag != tag_val)
    return 1;
  in_uint8(self->in_s, l);
  if (l & 0x80)
  {
    l = l & ~0x80;
    *len = 0;
    while (l > 0)
    {
      in_uint8(self->in_s, i);
      *len = (*len << 8) | i;
      l--;
    }
  }
  else
    *len = l;
  if (s_check(self->in_s))
    return 0;
  else
    return 1;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_parse_domain_params(struct xrdp_mcs* self)
{
  int len;

  if (xrdp_mcs_ber_parse_header(self, MCS_TAG_DOMAIN_PARAMS, &len) != 0)
    return 1;
  in_uint8s(self->in_s, len);
  if (s_check(self->in_s))
    return 0;
  else
    return 1;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_recv_connect_initial(struct xrdp_mcs* self)
{
  int len;

  if (xrdp_iso_recv(self->iso_layer) != 0)
    return 1;
  if (xrdp_mcs_ber_parse_header(self, MCS_CONNECT_INITIAL, &len) != 0)
    return 1;
  if (xrdp_mcs_ber_parse_header(self, BER_TAG_OCTET_STRING, &len) != 0)
    return 1;
  in_uint8s(self->in_s, len);
  if (xrdp_mcs_ber_parse_header(self, BER_TAG_OCTET_STRING, &len) != 0)
    return 1;
  in_uint8s(self->in_s, len);
  if (xrdp_mcs_ber_parse_header(self, BER_TAG_BOOLEAN, &len) != 0)
    return 1;
  in_uint8s(self->in_s, len);
  if (xrdp_mcs_parse_domain_params(self) != 0)
    return 1;
  if (xrdp_mcs_parse_domain_params(self) != 0)
    return 1;
  if (xrdp_mcs_parse_domain_params(self) != 0)
    return 1;
  if (xrdp_mcs_ber_parse_header(self, BER_TAG_OCTET_STRING, &len) != 0)
    return 1;
  /* make a copy of client mcs data */
  init_stream(self->client_mcs_data, len);
  out_uint8a(self->client_mcs_data, self->in_s->p, len);
  in_uint8s(self->in_s, len);
  s_mark_end(self->client_mcs_data);
  if (s_check_end(self->in_s))
    return 0;
  else
    return 1;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_recv_edrq(struct xrdp_mcs* self)
{
  int opcode;

  if (xrdp_iso_recv(self->iso_layer) != 0)
    return 1;
  in_uint8(self->in_s, opcode);
  if ((opcode >> 2) != MCS_EDRQ)
    return 1;
  in_uint8s(self->in_s, 2);
  in_uint8s(self->in_s, 2);
  if (opcode & 2)
  {
    in_uint16_be(self->in_s, self->userid);
  }
  if (!(s_check_end(self->in_s)))
    return 1;
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_recv_aurq(struct xrdp_mcs* self)
{
  int opcode;

  if (xrdp_iso_recv(self->iso_layer) != 0)
    return 1;
  in_uint8(self->in_s, opcode);
  if ((opcode >> 2) != MCS_AURQ)
    return 1;
  if (opcode & 2)
  {
    in_uint16_be(self->in_s, self->userid);
  }
  if (!(s_check_end(self->in_s)))
    return 1;
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_send_aucf(struct xrdp_mcs* self)
{
  if (xrdp_iso_init(self->iso_layer, 4) != 0)
    return 1;
  out_uint8(self->out_s, ((MCS_AUCF << 2) | 2));
  out_uint8s(self->out_s, 1);
  out_uint16_be(self->out_s, self->userid);
  s_mark_end(self->out_s);
  if (xrdp_iso_send(self->iso_layer) != 0)
    return 1;
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_recv_cjrq(struct xrdp_mcs* self)
{
  int opcode;

  if (xrdp_iso_recv(self->iso_layer) != 0)
    return 1;
  in_uint8(self->in_s, opcode);
  if ((opcode >> 2) != MCS_CJRQ)
    return 1;
  in_uint8s(self->in_s, 4);
  if (opcode & 2)
  {
    in_uint8s(self->in_s, 2);
  }
  if (!(s_check_end(self->in_s)))
    return 1;
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_ber_out_header(struct xrdp_mcs* self, int tag_val, int len)
{
  if (tag_val > 0xff)
  {
    out_uint16_be(self->out_s, tag_val);
  }
  else
  {
    out_uint8(self->out_s, tag_val);
  }
  if (len >= 0x80)
  {
    out_uint8(self->out_s, 0x82);
    out_uint16_be(self->out_s, len);
  }
  else
  {
    out_uint8(self->out_s, len);
  }
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_ber_out_int8(struct xrdp_mcs* self, int value)
{
  xrdp_mcs_ber_out_header(self, BER_TAG_INTEGER, 1);
  out_uint8(self->out_s, value);
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_ber_out_int16(struct xrdp_mcs* self, int value)
{
  xrdp_mcs_ber_out_header(self, BER_TAG_INTEGER, 2);
  out_uint8(self->out_s, value >> 8);
  out_uint8(self->out_s, value);
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_ber_out_int24(struct xrdp_mcs* self, int value)
{
  xrdp_mcs_ber_out_header(self, BER_TAG_INTEGER, 3);
  out_uint8(self->out_s, value >> 16);
  out_uint8(self->out_s, value >> 8);
  out_uint8(self->out_s, value);
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_out_domain_params(struct xrdp_mcs* self, int max_channels,
                               int max_users, int max_tokens,
                               int max_pdu_size)
{
  xrdp_mcs_ber_out_header(self, MCS_TAG_DOMAIN_PARAMS, 26);
  xrdp_mcs_ber_out_int8(self, max_channels);
  xrdp_mcs_ber_out_int8(self, max_users);
  xrdp_mcs_ber_out_int8(self, max_tokens);
  xrdp_mcs_ber_out_int8(self, 1);
  xrdp_mcs_ber_out_int8(self, 0);
  xrdp_mcs_ber_out_int8(self, 1);
  xrdp_mcs_ber_out_int24(self, max_pdu_size);
  xrdp_mcs_ber_out_int8(self, 2);
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_send_connect_response(struct xrdp_mcs* self)
{
  int data_len;

  data_len = self->server_mcs_data->end - self->server_mcs_data->data;
  xrdp_iso_init(self->iso_layer, 512);
  xrdp_mcs_ber_out_header(self, MCS_CONNECT_RESPONSE, 313);
  xrdp_mcs_ber_out_header(self, BER_TAG_RESULT, 1);
  out_uint8(self->out_s, 0);
  xrdp_mcs_ber_out_header(self, BER_TAG_INTEGER, 1);
  out_uint8(self->out_s, 0);
  xrdp_mcs_out_domain_params(self, 2, 2, 0, 0xffff);
  xrdp_mcs_ber_out_header(self, BER_TAG_OCTET_STRING, data_len);
  /* mcs data */
  out_uint8a(self->out_s, self->server_mcs_data->data, data_len);
  s_mark_end(self->out_s);
  if (xrdp_iso_send(self->iso_layer) != 0)
    return 1;
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_incoming(struct xrdp_mcs* self)
{
  DEBUG(("  in xrdp_mcs_incoming\n\r"));
  if (xrdp_iso_incoming(self->iso_layer) != 0)
    return 1;
  if (xrdp_mcs_recv_connect_initial(self) != 0)
    return 1;
  if (xrdp_mcs_send_connect_response(self) != 0)
    return 1;
  if (xrdp_mcs_recv_edrq(self) != 0)
    return 1;
  if (xrdp_mcs_recv_aurq(self) != 0)
    return 1;
  if (xrdp_mcs_send_aucf(self) != 0)
    return 1;
  if (xrdp_mcs_recv_cjrq(self) != 0)
    return 1;
  if (xrdp_mcs_send_cjcf(self, self->userid + MCS_USERCHANNEL_BASE) != 0)
    return 1;
  if (xrdp_mcs_recv_cjrq(self) != 0)
    return 1;
  if (xrdp_mcs_send_cjcf(self, MCS_GLOBAL_CHANNEL) != 0)
    return 1;
  DEBUG(("  out xrdp_mcs_incoming\n\r"));
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_init(struct xrdp_mcs* self, int len)
{
  xrdp_iso_init(self->iso_layer, len + 8);
  s_push_layer(self->out_s, mcs_hdr, 8);
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_send(struct xrdp_mcs* self)
{
  int len;

  DEBUG(("  in xrdp_mcs_send\n\r"));
  s_pop_layer(self->out_s, mcs_hdr);
  len = (self->out_s->end - self->out_s->p) - 8;
  len = len | 0x8000;
  out_uint8(self->out_s, MCS_SDIN << 2);
  out_uint16_be(self->out_s, self->userid);
  out_uint16_be(self->out_s, MCS_GLOBAL_CHANNEL);
  out_uint8(self->out_s, 0x70);
  out_uint16_be(self->out_s, len);
  if (xrdp_iso_send(self->iso_layer) != 0)
    return 1;
  DEBUG(("  out xrdp_mcs_send\n\r"));
  return 0;
}

/*****************************************************************************/
/* returns error */
int xrdp_mcs_disconnect(struct xrdp_mcs* self)
{
  int len;

  xrdp_mcs_init(self, 100);
  s_mark_end(self->out_s);
  s_pop_layer(self->out_s, mcs_hdr);
  len = (self->out_s->end - self->out_s->p) - 8;
  len = len | 0x8000;
  out_uint8(self->out_s, MCS_DPUM << 2);
  out_uint16_be(self->out_s, self->userid);
  out_uint16_be(self->out_s, MCS_GLOBAL_CHANNEL);
  out_uint8(self->out_s, 0x70);
  out_uint16_be(self->out_s, len);
  if (xrdp_iso_send(self->iso_layer) != 0)
    return 1;
  return 0;
}