iso.c

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/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Protocol services - ISO layer
   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>

/* 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);
}

static void
iso_send_connection_request(char *username)
{
    STREAM s;
    int length = 30 + strlen(username);

    s = tcp_init(length);

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

    out_uint8(s, length - 5);   /* hdrlen */
    out_uint8(s, ISO_PDU_CR);
    out_uint16(s, 0);   /* dst_ref */
    out_uint16(s, 0);   /* src_ref */
    out_uint8(s, 0);    /* class */

    out_uint8p(s, "Cookie: mstshash=", strlen("Cookie: mstshash="));
    out_uint8p(s, username, strlen(username));

    out_uint8(s, 0x0d); /* Unknown */
    out_uint8(s, 0x0a); /* Unknown */

    s_mark_end(s);
    tcp_send(s);
}

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

    s = tcp_recv(NULL, 4);
    if (s == NULL)
        return NULL;
    in_uint8(s, version);
    if (rdpver != NULL)
        *rdpver = version;
    if (version == 3)
    {
        in_uint8s(s, 1);    /* pad */
        in_uint16_be(s, length);
    }
    else
    {
        in_uint8(s, length);
        if (length & 0x80)
        {
            length &= ~0x80;
            next_be(s, length);
        }
    }
    s = tcp_recv(s, length - 4);
    if (s == NULL)
        return NULL;
    if (version != 3)
        return s;
    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(uint8 * rdpver)
{
    STREAM s;
    uint8 code = 0;

    s = iso_recv_msg(&code, rdpver);
    if (s == NULL)
        return NULL;
    if (rdpver != NULL)
        if (*rdpver != 3)
            return s;
    if (code != ISO_PDU_DT)
    {
        error("expected DT, got 0x%x\n", code);
        return NULL;
    }
    return s;
}

/* Establish a connection up to the ISO layer */
BOOL
iso_connect(char *server, char *username)
{
    uint8 code = 0;

    if (!tcp_connect(server))
        return False;

    iso_send_connection_request(username);

    if (iso_recv_msg(&code, NULL) == NULL)
        return False;

    if (code != ISO_PDU_CC)
    {
        error("expected CC, got 0x%x\n", code);
        tcp_disconnect();
        return False;
    }

    return True;
}

/* Establish a reconnection up to the ISO layer */
BOOL
iso_reconnect(char *server)
{
    uint8 code = 0;

    if (!tcp_connect(server))
        return False;

    iso_send_msg(ISO_PDU_CR);

    if (iso_recv_msg(&code, NULL) == NULL)
        return False;

    if (code != ISO_PDU_CC)
    {
        error("expected CC, got 0x%x\n", code);
        tcp_disconnect();
        return False;
    }

    return True;
}

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

/* reset the state to support reconnecting */
void
iso_reset_state(void)
{
    tcp_reset_state();
}