/* 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 2.1 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 

 *

 * 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_source_tag (task, g_socks5_proxy_connect_async);

  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);