/*
   rdesktop: A Remote Desktop Protocol client.
   Protocol services - ISO layer
   Copyright (C) Matthew Chapman 1999-2000
   
   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"

/* Send a self-contained ISO PDU */
static void
iso_send_msg (uint8 code)
{
  STREAM s;

  s = tcp_init (11);

  out_uint8 (s, 3);		/* version */
  out_uint8 (s, 0);		/* reserved */
  out_uint16_be (s, 11);	/* length */

  out_uint8 (s, 6);		/* hdrlen */
  out_uint8 (s, code);
  out_uint16 (s, 0);		/* dst_ref */
  out_uint16 (s, 0);		/* src_ref */
  out_uint8 (s, 0);		/* class */

  s_mark_end (s);
  tcp_send (s);
}

/* Receive a message on the ISO layer, return code */
static STREAM
iso_recv_msg (uint8 * code)
{
  STREAM s;
  uint16 length;
  uint8 version;

  s = tcp_recv (4);
  if (s == NULL)
    return False;

  in_uint8 (s, version);
  if (version != 3)
    {
      ERROR ("TPKT v%d\n", version);
      return False;
    }

  in_uint8s (s, 1);		/* pad */
  in_uint16_be (s, length);

  s = tcp_recv (length - 4);
  if (s == NULL)
    return False;

  in_uint8s (s, 1);		/* hdrlen */
  in_uint8 (s, *code);

  if (*code == ISO_PDU_DT)
    {
      in_uint8s (s, 1);		/* eot */
      return s;
    }

  in_uint8s (s, 5);		/* dst_ref, src_ref, class */
  return s;
}

/* Initialise ISO transport data packet */
STREAM iso_init (int length)
{
  STREAM s;

  s = tcp_init (length + 7);
  s_push_layer (s, iso_hdr, 7);

  return s;
}

/* Send an ISO data PDU */
void
iso_send (STREAM s)
{
  uint16 length;

  s_pop_layer (s, iso_hdr);
  length = s->end - s->p;

  out_uint8 (s, 3);		/* version */
  out_uint8 (s, 0);		/* reserved */
  out_uint16_be (s, length);

  out_uint8 (s, 2);		/* hdrlen */
  out_uint8 (s, ISO_PDU_DT);	/* code */
  out_uint8 (s, 0x80);		/* eot */

  tcp_send (s);
}

/* Receive ISO transport data packet */
STREAM iso_recv ()
{
  STREAM s;
  uint8 code;

  s = iso_recv_msg (&code);
  if ((s == NULL) || (code != ISO_PDU_DT))
    {
      ERROR ("expected DT, got %d\n", code);
      return False;
    }

  return s;
}

/* Establish a connection up to the ISO layer */
Bool iso_connect (char *server)
{
  uint8 code;

  if (!tcp_connect (server))
    return False;

  iso_send_msg (ISO_PDU_CR);

  if ((iso_recv_msg (&code) == NULL) || (code != ISO_PDU_CC))
    {
      ERROR ("expected CC, got %d\n", code);
      tcp_disconnect ();
      return False;
    }

  return True;
}

/* Disconnect from the ISO layer */
void
iso_disconnect ()
{
  iso_send_msg (ISO_PDU_DR);
  tcp_disconnect ();
}

#ifdef SERVER

/* Establish a connection up to the ISO layer */
Bool iso_listen(char *server)
{
  uint8 code;

  if (!tcp_listen(server))
    return False;

  if ((iso_recv_msg(&code) == NULL) || (code != ISO_PDU_CR))
  {
    ERROR("expected CR, got %d\n", code);
    tcp_disconnect();
    return False;
  }

  iso_send_msg(ISO_PDU_CC);

  return True;
}

#endif /* SERVER */