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 /* GIO - GLib Input, Output and Streaming Library
 *
 * Copyright (C) 2008, 2010 Collabora, Ltd.
 * Copyright (C) 2008 Nokia Corporation. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 * Author:  Youness Alaoui <youness.alaoui@collabora.co.uk
 *
 * Contributors:
 *          Nicolas Dufresne <nicolas.dufresne@collabora.co.uk>
 */

#include "config.h"

#include "gsocks5proxy.h"

#include <string.h>

#include "giomodule.h"
#include "giomodule-priv.h"
#include "giostream.h"
#include "ginetaddress.h"
#include "ginputstream.h"
#include "glibintl.h"
#include "goutputstream.h"
#include "gproxy.h"
#include "gproxyaddress.h"
#include "gtask.h"

#define SOCKS5_VERSION            0x05

#define SOCKS5_CMD_CONNECT        0x01
#define SOCKS5_CMD_BIND           0x02
#define SOCKS5_CMD_UDP_ASSOCIATE  0x03

#define SOCKS5_ATYP_IPV4          0x01
#define SOCKS5_ATYP_DOMAINNAME    0x03
#define SOCKS5_ATYP_IPV6          0x04

#define SOCKS5_AUTH_VERSION       0x01

#define SOCKS5_AUTH_NONE          0x00
#define SOCKS5_AUTH_GSSAPI        0x01
#define SOCKS5_AUTH_USR_PASS      0x02
#define SOCKS5_AUTH_NO_ACCEPT     0xff

#define SOCKS5_MAX_LEN            255
#define SOCKS5_RESERVED           0x00

#define SOCKS5_REP_SUCCEEDED      0x00
#define SOCKS5_REP_SRV_FAILURE    0x01
#define SOCKS5_REP_NOT_ALLOWED    0x02
#define SOCKS5_REP_NET_UNREACH    0x03
#define SOCKS5_REP_HOST_UNREACH   0x04
#define SOCKS5_REP_REFUSED        0x05
#define SOCKS5_REP_TTL_EXPIRED    0x06
#define SOCKS5_REP_CMD_NOT_SUP    0x07
#define SOCKS5_REP_ATYPE_NOT_SUP  0x08


struct _GSocks5Proxy
{
  GObject parent;
};

struct _GSocks5ProxyClass
{
  GObjectClass parent_class;
};

static void g_socks5_proxy_iface_init (GProxyInterface *proxy_iface);

#define g_socks5_proxy_get_type _g_socks5_proxy_get_type
G_DEFINE_TYPE_WITH_CODE (GSocks5Proxy, g_socks5_proxy, G_TYPE_OBJECT,
                         G_IMPLEMENT_INTERFACE (G_TYPE_PROXY,
                                                g_socks5_proxy_iface_init)
                         _g_io_modules_ensure_extension_points_registered ();
                         g_io_extension_point_implement (G_PROXY_EXTENSION_POINT_NAME,
                                                         g_define_type_id,
                                                         "socks5",
                                                         0))

static void
g_socks5_proxy_finalize (GObject *object)
{
  /* must chain up */
  G_OBJECT_CLASS (g_socks5_proxy_parent_class)->finalize (object);
}

static void
g_socks5_proxy_init (GSocks5Proxy *proxy)
{
}

/*
 * +----+----------+----------+
 * |VER | NMETHODS | METHODS  |
 * +----+----------+----------+
 * | 1  |    1     | 1 to 255 |
 * +----+----------+----------+
 */
#define SOCKS5_NEGO_MSG_LEN       4
static gint
set_nego_msg (guint8 *msg, gboolean has_auth)
{
  gint len = 3;

  msg[0] = SOCKS5_VERSION;
  msg[1] = 0x01; /* number of methods supported */
  msg[2] = SOCKS5_AUTH_NONE;

  /* add support for authentication method */
  if (has_auth)
    {
      msg[1] = 0x02; /* number of methods supported */
      msg[3] = SOCKS5_AUTH_USR_PASS;
      len++;
    }

  return len;
}


/*
 * +----+--------+
 * |VER | METHOD |
 * +----+--------+
 * | 1  |   1    |
 * +----+--------+
 */
#define SOCKS5_NEGO_REP_LEN       2
static gboolean
parse_nego_reply (const guint8 *data,
                  gboolean     has_auth,
                  gboolean    *must_auth,
                  GError     **error)
{
  if (data[0] != SOCKS5_VERSION)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                           _("The server is not a SOCKSv5 proxy server."));
      return FALSE;
    }

  switch (data[1])
    {
      case SOCKS5_AUTH_NONE:
        *must_auth = FALSE;
        break;

      case SOCKS5_AUTH_USR_PASS:
        if (!has_auth)
          {
            g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_NEED_AUTH,
                           _("The SOCKSv5 proxy requires authentication."));
            return FALSE;
          }
        *must_auth = TRUE;
        break;

      case SOCKS5_AUTH_GSSAPI:
      case SOCKS5_AUTH_NO_ACCEPT:
      default:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_AUTH_FAILED,
                             _("The SOCKSv5 proxy requires an authentication "
                               "method that is not supported by GLib."));
        return FALSE;
        break;
    }

  return TRUE;
}

#define SOCKS5_AUTH_MSG_LEN       515
static gint
set_auth_msg (guint8      *msg,
              const gchar *username,
              const gchar *password,
              GError **error)
{
  gint len = 0;
  gint ulen = 0; /* username length */
  gint plen = 0; /* Password length */

  if (username)
    ulen = strlen (username);

  if (password)
    plen = strlen (password);

  if (ulen > SOCKS5_MAX_LEN || plen > SOCKS5_MAX_LEN)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                           _("Username or password is too long for SOCKSv5 "
                             "protocol."));
      return -1;
    }

  msg[len++] = SOCKS5_AUTH_VERSION;
  msg[len++] = ulen;

  if (ulen > 0)
    memcpy (msg + len, username, ulen);

  len += ulen;
  msg[len++] = plen;

  if (plen > 0)
    memcpy (msg + len, password, plen);

  len += plen;

  return len;
}


static gboolean
check_auth_status (const guint8 *data, GError **error)
{
  if (data[0] != SOCKS5_VERSION
      || data[1] != SOCKS5_REP_SUCCEEDED)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_AUTH_FAILED,
                           _("SOCKSv5 authentication failed due to wrong "
                             "username or password."));
      return FALSE;
    }
  return TRUE;
}

/*
 * +----+-----+-------+------+----------+----------+
 * |VER | CMD |  RSV  | ATYP | DST.ADDR | DST.PORT |
 * +----+-----+-------+------+----------+----------+
 * | 1  |  1  | X'00' |  1   | Variable |    2     |
 * +----+-----+-------+------+----------+----------+
 * DST.ADDR is a string with first byte being the size. So DST.ADDR may not be
 * longer then 256 bytes.
 */
#define SOCKS5_CONN_MSG_LEN       262
static gint
set_connect_msg (guint8       *msg,
                 const gchar *hostname,
                 guint16      port,
                 GError     **error)
{
  guint len = 0;

  msg[len++] = SOCKS5_VERSION;
  msg[len++] = SOCKS5_CMD_CONNECT;
  msg[len++] = SOCKS5_RESERVED;

  if (g_hostname_is_ip_address (hostname))
    {
      GInetAddress *addr = g_inet_address_new_from_string (hostname);
      gsize addr_len = g_inet_address_get_native_size (addr);

      /* We are cheating for simplicity, here's the logic:
       *   1 = IPV4 = 4 bytes / 4
       *   4 = IPV6 = 16 bytes / 4 */
      msg[len++] = addr_len / 4;
      memcpy (msg + len, g_inet_address_to_bytes (addr), addr_len);
      len += addr_len;

      g_object_unref (addr);
    }
  else
    {
      gsize host_len = strlen (hostname);

      if (host_len > SOCKS5_MAX_LEN)
        {
          g_set_error (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                       _("Hostname '%s' is too long for SOCKSv5 protocol"),
                       hostname);
          return -1;
        }

      msg[len++] = SOCKS5_ATYP_DOMAINNAME;
      msg[len++] = (guint8) host_len;
      memcpy (msg + len, hostname, host_len);
      len += host_len;
    }

    {
      guint16 hp = g_htons (port);
      memcpy (msg + len, &hp, 2);
      len += 2;
    }

  return len;
}

/*
 * +----+-----+-------+------+----------+----------+
 * |VER | REP |  RSV  | ATYP | BND.ADDR | BND.PORT |
 * +----+-----+-------+------+----------+----------+
 * | 1  |  1  | X'00' |  1   | Variable |    2     |
 * +----+-----+-------+------+----------+----------+
 * This reply need to be read by small part to determin size. Buffer
 * size is determined in function of the biggest part to read.
 *
 * The parser only requires 4 bytes.
 */
#define SOCKS5_CONN_REP_LEN       255
static gboolean
parse_connect_reply (const guint8 *data, gint *atype, GError **error)
{
  if (data[0] != SOCKS5_VERSION)
    {
      g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                           _("The server is not a SOCKSv5 proxy server."));
      return FALSE;
    }

  switch (data[1])
    {
      case SOCKS5_REP_SUCCEEDED:
        if (data[2] != SOCKS5_RESERVED)
          {
            g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                           _("The server is not a SOCKSv5 proxy server."));
            return FALSE;
          }

        switch (data[3])
          {
          case SOCKS5_ATYP_IPV4:
          case SOCKS5_ATYP_IPV6:
          case SOCKS5_ATYP_DOMAINNAME:
            *atype = data[3];
            break;

          default:
            g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                           _("The SOCKSv5 proxy server uses unknown address type."));
            return FALSE;
          }
        break;

      case SOCKS5_REP_SRV_FAILURE:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                             _("Internal SOCKSv5 proxy server error."));
        return FALSE;
        break;

      case SOCKS5_REP_NOT_ALLOWED:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_NOT_ALLOWED,
                             _("SOCKSv5 connection not allowed by ruleset."));
        return FALSE;
        break;

      case SOCKS5_REP_TTL_EXPIRED:
      case SOCKS5_REP_HOST_UNREACH:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_HOST_UNREACHABLE,
                             _("Host unreachable through SOCKSv5 server."));
        return FALSE;
        break;

      case SOCKS5_REP_NET_UNREACH:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NETWORK_UNREACHABLE,
                             _("Network unreachable through SOCKSv5 proxy."));
        return FALSE;
        break;

      case SOCKS5_REP_REFUSED:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CONNECTION_REFUSED,
                             _("Connection refused through SOCKSv5 proxy."));
        return FALSE;
        break;

      case SOCKS5_REP_CMD_NOT_SUP:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                             _("SOCKSv5 proxy does not support 'connect' command."));
        return FALSE;
        break;

      case SOCKS5_REP_ATYPE_NOT_SUP:
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                             _("SOCKSv5 proxy does not support provided address type."));
        return FALSE;
        break;

      default: /* Unknown error */
        g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_PROXY_FAILED,
                             _("Unknown SOCKSv5 proxy error."));
        return FALSE;
        break;
    }

  return TRUE;
}

static GIOStream *
g_socks5_proxy_connect (GProxy            *proxy,
                        GIOStream         *io_stream,
                        GProxyAddress     *proxy_address,
                        GCancellable      *cancellable,
                        GError          **error)
{
  gboolean has_auth;
  GInputStream *in;
  GOutputStream *out;
  const gchar *hostname;
  guint16 port;
  const gchar *username;
  const gchar *password;

  hostname = g_proxy_address_get_destination_hostname (proxy_address);
  port = g_proxy_address_get_destination_port (proxy_address);
  username = g_proxy_address_get_username (proxy_address);
  password = g_proxy_address_get_password (proxy_address);

  has_auth = username || password;
  
  in = g_io_stream_get_input_stream (io_stream);
  out = g_io_stream_get_output_stream (io_stream);

  /* Send SOCKS5 handshake */
    {
      guint8 msg[SOCKS5_NEGO_MSG_LEN];
      gint len;

      len = set_nego_msg (msg, has_auth);

      if (!g_output_stream_write_all (out, msg, len, NULL,
                                      cancellable, error))
        goto error;
    }

  /* Receive SOCKS5 response and reply with authentication if required */
    {
      guint8 data[SOCKS5_NEGO_REP_LEN];
      gboolean must_auth = FALSE;

      if (!g_input_stream_read_all (in, data, sizeof (data), NULL,
                                    cancellable, error))
        goto error;

      if (!parse_nego_reply (data, has_auth, &must_auth, error))
          goto error;

      if (must_auth)
        {
          guint8 msg[SOCKS5_AUTH_MSG_LEN];
          gint len;

          len = set_auth_msg (msg, username, password, error);

          if (len < 0)
            goto error;
          
          if (!g_output_stream_write_all (out, msg, len, NULL,
                                          cancellable, error))
            goto error;

          if (!g_input_stream_read_all (in, data, sizeof (data), NULL,
                                        cancellable, error))
            goto error;

          if (!check_auth_status (data, error))
            goto error;
        }
    }

  /* Send SOCKS5 connection request */
    {
      guint8 msg[SOCKS5_CONN_MSG_LEN];
      gint len;
      
      len = set_connect_msg (msg, hostname, port, error);

      if (len < 0)
        goto error;

      if (!g_output_stream_write_all (out, msg, len, NULL,
                                      cancellable, error))
        goto error;
    }

  /* Read SOCKS5 response */
    {
      guint8 data[SOCKS5_CONN_REP_LEN];
      gint atype;

      if (!g_input_stream_read_all (in, data, 4, NULL,
                                    cancellable, error))
        goto error;

      if (!parse_connect_reply (data, &atype, error))
        goto error;

      switch (atype)
        {
          case SOCKS5_ATYP_IPV4:
            if (!g_input_stream_read_all (in, data, 6, NULL,
                                          cancellable, error))
              goto error;
            break;

          case SOCKS5_ATYP_IPV6:
            if (!g_input_stream_read_all (in, data, 18, NULL,
                                          cancellable, error))
              goto error;
            break;

          case SOCKS5_ATYP_DOMAINNAME:
            if (!g_input_stream_read_all (in, data, 1, NULL,
                                          cancellable, error))
              goto error;
            if (!g_input_stream_read_all (in, data, data[0] + 2, NULL,
                                          cancellable, error))
              goto error;
            break;
        }
    }

  return g_object_ref (io_stream);

error:
  return NULL;
}


typedef struct
{
  GIOStream *io_stream;
  gchar *hostname;
  guint16 port;
  gchar *username;
  gchar *password;
  guint8 *buffer;
  gssize length;
  gssize offset;
} ConnectAsyncData;

static void nego_msg_write_cb         (GObject          *source,
                                       GAsyncResult     *res,
                                       gpointer          user_data);
static void nego_reply_read_cb        (GObject          *source,
                                       GAsyncResult     *res,
                                       gpointer          user_data);
static void auth_msg_write_cb         (GObject          *source,
                                       GAsyncResult     *res,
                                       gpointer          user_data);
static void auth_reply_read_cb        (GObject          *source,
                                       GAsyncResult     *result,
                                       gpointer          user_data);
static void send_connect_msg          (GTask            *task);
static void connect_msg_write_cb      (GObject          *source,
                                       GAsyncResult     *result,
                                       gpointer          user_data);
static void connect_reply_read_cb     (GObject          *source,
                                       GAsyncResult     *result,
                                       gpointer          user_data);
static void connect_addr_len_read_cb  (GObject          *source,
                                       GAsyncResult     *result,
                                       gpointer          user_data);
static void connect_addr_read_cb      (GObject          *source,
                                       GAsyncResult     *result,
                                       gpointer          user_data);

static void
free_connect_data (ConnectAsyncData *data)
{
  g_object_unref (data->io_stream);

  g_free (data->hostname);
  g_free (data->username);
  g_free (data->password);
  g_free (data->buffer);

  g_slice_free (ConnectAsyncData, data);
}

static void
do_read (GAsyncReadyCallback callback, GTask *task, ConnectAsyncData *data)
{
   GInputStream *in;
   in = g_io_stream_get_input_stream (data->io_stream);
   g_input_stream_read_async (in,
                              data->buffer + data->offset,
                              data->length - data->offset,
                              g_task_get_priority (task),
                              g_task_get_cancellable (task),
                              callback, task);
}

static void
do_write (GAsyncReadyCallback callback, GTask *task, ConnectAsyncData *data)
{
  GOutputStream *out;
  out = g_io_stream_get_output_stream (data->io_stream);
  g_output_stream_write_async (out,
                               data->buffer + data->offset,
                               data->length - data->offset,
                               g_task_get_priority (task),
                               g_task_get_cancellable (task),
                               callback, task);
}

static void
g_socks5_proxy_connect_async (GProxy               *proxy,
                              GIOStream            *io_stream,
                              GProxyAddress        *proxy_address,
                              GCancellable         *cancellable,
                              GAsyncReadyCallback   callback,
                              gpointer              user_data)
{
  GTask *task;
  ConnectAsyncData *data;

  data = g_slice_new0 (ConnectAsyncData);
  data->io_stream = g_object_ref (io_stream);

  task = g_task_new (proxy, cancellable, callback, user_data);
  g_task_set_task_data (task, data, (GDestroyNotify) free_connect_data);

  g_object_get (G_OBJECT (proxy_address),
                "destination-hostname", &data->hostname,
                "destination-port", &data->port,
                "username", &data->username,
                "password", &data->password,
                NULL);

  data->buffer = g_malloc0 (SOCKS5_NEGO_MSG_LEN);
  data->length = set_nego_msg (data->buffer,
                               data->username || data->password);
  data->offset = 0;

  do_write (nego_msg_write_cb, task, data);
}


static void
nego_msg_write_cb (GObject      *source,
                   GAsyncResult *res,
                   gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize written;

  written = g_output_stream_write_finish (G_OUTPUT_STREAM (source),
                                          res, &error);

  if (written < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += written;

  if (data->offset == data->length)
    {
      g_free (data->buffer);

      data->buffer = g_malloc0 (SOCKS5_NEGO_REP_LEN);
      data->length = SOCKS5_NEGO_REP_LEN;
      data->offset = 0;

      do_read (nego_reply_read_cb, task, data);
    }
  else
    {
      do_write (nego_msg_write_cb, task, data);
    }
}

static void
nego_reply_read_cb (GObject      *source,
                    GAsyncResult *res,
                    gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize read;

  read = g_input_stream_read_finish (G_INPUT_STREAM (source),
                                     res, &error);

  if (read < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += read;
  
  if (data->offset == data->length)
    {
      GError *error = NULL;
      gboolean must_auth = FALSE;
      gboolean has_auth = data->username || data->password;

      if (!parse_nego_reply (data->buffer, has_auth, &must_auth, &error))
        {
          g_task_return_error (task, error);
          g_object_unref (task);
          return;
        }

      if (must_auth)
        {
          g_free (data->buffer);

          data->buffer = g_malloc0 (SOCKS5_AUTH_MSG_LEN);
          data->length = set_auth_msg (data->buffer,
                                       data->username,
                                       data->password,
                                       &error);
          data->offset = 0;

          if (data->length < 0)
            {
              g_task_return_error (task, error);
              g_object_unref (task);
              return;
            }
          
          do_write (auth_msg_write_cb, task, data);
        }
      else
        {
          send_connect_msg (task);
        }
    }
  else
    {
      do_read (nego_reply_read_cb, task, data);
    }
}

static void
auth_msg_write_cb (GObject      *source,
                   GAsyncResult *result,
                   gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize written;

  written = g_output_stream_write_finish (G_OUTPUT_STREAM (source),
                                          result, &error);
  
  if (written < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += written;

  if (data->offset == data->length)
    {
      g_free (data->buffer);

      data->buffer = g_malloc0 (SOCKS5_NEGO_REP_LEN);
      data->length = SOCKS5_NEGO_REP_LEN;
      data->offset = 0;

      do_read (auth_reply_read_cb, task, data);
    }
  else
    {
      do_write (auth_msg_write_cb, task, data);
    }
}

static void
auth_reply_read_cb (GObject      *source,
                    GAsyncResult *result,
                    gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize read;

  read = g_input_stream_read_finish (G_INPUT_STREAM (source),
                                     result, &error);

  if (read < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += read;

  if (data->offset == data->length)
    {
      if (!check_auth_status (data->buffer, &error))
        {
          g_task_return_error (task, error);
          g_object_unref (task);
          return;
        }
        
      send_connect_msg (task);
    }
  else
    {
      do_read (auth_reply_read_cb, task, data);
    }
}

static void
send_connect_msg (GTask *task)
{
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;

  g_free (data->buffer);

  data->buffer = g_malloc0 (SOCKS5_CONN_MSG_LEN);
  data->length = set_connect_msg (data->buffer,
                                  data->hostname,
                                  data->port,
                                  &error);
  data->offset = 0;
  
  if (data->length < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  do_write (connect_msg_write_cb, task, data);
}

static void
connect_msg_write_cb (GObject      *source,
                      GAsyncResult *result,
                      gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize written;

  written = g_output_stream_write_finish (G_OUTPUT_STREAM (source),
                                          result, &error);
  
  if (written < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += written;

  if (data->offset == data->length)
    {
      g_free (data->buffer);

      data->buffer = g_malloc0 (SOCKS5_CONN_REP_LEN);
      data->length = 4;
      data->offset = 0;

      do_read (connect_reply_read_cb, task, data);
    }
  else
    {
      do_write (connect_msg_write_cb, task, data);
    }
}

static void
connect_reply_read_cb (GObject       *source,
                       GAsyncResult  *result,
                       gpointer       user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize read;

  read = g_input_stream_read_finish (G_INPUT_STREAM (source),
                                     result, &error);

  if (read < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += read;

  if (data->offset == data->length)
    {
      gint atype;

      if (!parse_connect_reply (data->buffer, &atype, &error))
        {
          g_task_return_error (task, error);
          g_object_unref (task);
          return;
        }

      switch (atype)
        {
          case SOCKS5_ATYP_IPV4:
            data->length = 6;
            data->offset = 0;
            do_read (connect_addr_read_cb, task, data);
            break;

          case SOCKS5_ATYP_IPV6:
            data->length = 18;
            data->offset = 0;
            do_read (connect_addr_read_cb, task, data);
            break;

          case SOCKS5_ATYP_DOMAINNAME:
            data->length = 1;
            data->offset = 0;
            do_read (connect_addr_len_read_cb, task, data);
            break;
        }
    }
  else
    {
      do_read (connect_reply_read_cb, task, data);
    }
}

static void
connect_addr_len_read_cb (GObject      *source,
                          GAsyncResult *result,
                          gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize read;

  read = g_input_stream_read_finish (G_INPUT_STREAM (source),
                                     result, &error);

  if (read < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->length = data->buffer[0] + 2;
  data->offset = 0;

  do_read (connect_addr_read_cb, task, data);
}

static void
connect_addr_read_cb (GObject      *source,
                      GAsyncResult *result,
                      gpointer      user_data)
{
  GTask *task = user_data;
  ConnectAsyncData *data = g_task_get_task_data (task);
  GError *error = NULL;
  gssize read;

  read = g_input_stream_read_finish (G_INPUT_STREAM (source),
                                     result, &error);

  if (read < 0)
    {
      g_task_return_error (task, error);
      g_object_unref (task);
      return;
    }

  data->offset += read;

  if (data->offset == data->length)
    {
      g_task_return_pointer (task, g_object_ref (data->io_stream), g_object_unref);
      g_object_unref (task);
      return;
    }
  else
    {
      do_read (connect_reply_read_cb, task, data);
    }
}

static GIOStream *
g_socks5_proxy_connect_finish (GProxy       *proxy,
                               GAsyncResult *result,
                               GError      **error)
{
  return g_task_propagate_pointer (G_TASK (result), error);
}

static gboolean
g_socks5_proxy_supports_hostname (GProxy *proxy)
{
  return TRUE;
}

static void
g_socks5_proxy_class_init (GSocks5ProxyClass *class)
{
  GObjectClass *object_class;

  object_class = (GObjectClass *) class;
  object_class->finalize = g_socks5_proxy_finalize;
}

static void
g_socks5_proxy_iface_init (GProxyInterface *proxy_iface)
{
  proxy_iface->connect  = g_socks5_proxy_connect;
  proxy_iface->connect_async = g_socks5_proxy_connect_async;
  proxy_iface->connect_finish = g_socks5_proxy_connect_finish;
  proxy_iface->supports_hostname = g_socks5_proxy_supports_hostname;
}