/* GIO - GLib Input, Output and Streaming Library

 *

 * Copyright (C) 2010 Collabora, Ltd.

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * 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: Nicolas Dufresne <nicolas.dufresne@collabora.co.uk>

 */

#include "config.h"

#include "gproxyaddressenumerator.h"

#include <string.h>

#include "gasyncresult.h"

#include "ginetaddress.h"

#include "gioerror.h"

#include "glibintl.h"

#include "glib-private.h"

#include "gnetworkaddress.h"

#include "gnetworkingprivate.h"

#include "gproxy.h"

#include "gproxyaddress.h"

#include "gproxyresolver.h"

#include "gtask.h"

#include "gresolver.h"

#include "gsocketaddress.h"

#include "gsocketaddressenumerator.h"

#include "gsocketconnectable.h"

/**

 * GProxyAddressEnumerator:

 *

 * `GProxyAddressEnumerator` is a wrapper around

 * [class@Gio.SocketAddressEnumerator] which takes the [class@Gio.SocketAddress]

 * instances returned by the [class@Gio.SocketAddressEnumerator]

 * and wraps them in [class@Gio.ProxyAddress] instances, using the given

 * [property@Gio.ProxyAddressEnumerator:proxy-resolver].

 *

 * This enumerator will be returned (for example, by

 * [method@Gio.SocketConnectable.enumerate]) as appropriate when a proxy is

 * configured; there should be no need to manually wrap a

 * [class@Gio.SocketAddressEnumerator] instance with one.

 */

#define GET_PRIVATE(o) (G_PROXY_ADDRESS_ENUMERATOR (o)->priv)

enum

{

  PROP_0,

  PROP_URI,

  PROP_DEFAULT_PORT,

  PROP_CONNECTABLE,

  PROP_PROXY_RESOLVER

};

struct _GProxyAddressEnumeratorPrivate

{

  /* Destination address */

  GSocketConnectable *connectable;

  gchar              *dest_uri;

  guint16             default_port;

  gchar              *dest_hostname;

  guint16             dest_port;

  GList              *dest_ips;

  /* Proxy enumeration */

  GProxyResolver           *proxy_resolver;

  gchar                   **proxies;

  gchar                   **next_proxy;

  GSocketAddressEnumerator *addr_enum;

  GSocketAddress           *proxy_address;

  const gchar              *proxy_uri;

  gchar                    *proxy_type;

  gchar                    *proxy_username;

  gchar                    *proxy_password;

  gboolean                  supports_hostname;

  GList                    *next_dest_ip;

  GError                   *last_error;

  /* ever_enumerated is TRUE after we've returned a result for the first time

   * via g_proxy_address_enumerator_next() or _next_async(). If FALSE, we have

   * never returned yet, and should return an error if returning NULL because

   * it does not make sense for a proxy resolver to return NULL except on error.

   * (Whereas a DNS resolver would return NULL with no error to indicate "no

   * results", a proxy resolver would want to return "direct://" instead, so

   * NULL without error does not make sense for us.)

   *

   * But if ever_enumerated is TRUE, then we must not report any further errors

   * (except for G_IO_ERROR_CANCELLED), because this is an API contract of

   * GSocketAddressEnumerator.

   */

  gboolean                  ever_enumerated;

};

G_DEFINE_TYPE_WITH_PRIVATE (GProxyAddressEnumerator, g_proxy_address_enumerator, G_TYPE_SOCKET_ADDRESS_ENUMERATOR)

static void

save_userinfo (GProxyAddressEnumeratorPrivate *priv,

               const gchar *proxy)

{

  g_clear_pointer (&priv->proxy_username, g_free);

  g_clear_pointer (&priv->proxy_password, g_free);

  g_uri_split_with_user (proxy, G_URI_FLAGS_HAS_PASSWORD, NULL,

                         &priv->proxy_username, &priv->proxy_password,

                         NULL, NULL, NULL, NULL, NULL, NULL, NULL);

}

static void

next_enumerator (GProxyAddressEnumeratorPrivate *priv)

{

  if (priv->proxy_address)

    return;

  while (priv->addr_enum == NULL && *priv->next_proxy)

    {

      GSocketConnectable *connectable = NULL;

      GProxy *proxy;

      priv->proxy_uri = *priv->next_proxy++;

      g_free (priv->proxy_type);

      priv->proxy_type = g_uri_parse_scheme (priv->proxy_uri);

      if (priv->proxy_type == NULL)

  continue;

      /* Assumes hostnames are supported for unknown protocols */

      priv->supports_hostname = TRUE;

      proxy = g_proxy_get_default_for_protocol (priv->proxy_type);

      if (proxy)

        {

    priv->supports_hostname = g_proxy_supports_hostname (proxy);

    g_object_unref (proxy);

        }

      if (strcmp ("direct", priv->proxy_type) == 0)

  {

    if (priv->connectable)

      connectable = g_object_ref (priv->connectable);

    else

      connectable = g_network_address_new (priv->dest_hostname,

             priv->dest_port);

  }

      else

  {

    GError *error = NULL;

    int default_port;

    default_port = GLIB_PRIVATE_CALL (g_uri_get_default_scheme_port) (priv->proxy_type);

    if (default_port == -1)

      default_port = 0;

    connectable = g_network_address_parse_uri (priv->proxy_uri, default_port, &error);

    if (error)

      {

        g_warning ("Invalid proxy URI '%s': %s",

       priv->proxy_uri, error->message);

        g_error_free (error);

      }

    save_userinfo (priv, priv->proxy_uri);

  }

      if (connectable)

  {

    priv->addr_enum = g_socket_connectable_enumerate (connectable);

    g_object_unref (connectable);

  }

    }

}

static GSocketAddress *

g_proxy_address_enumerator_next (GSocketAddressEnumerator  *enumerator,

         GCancellable              *cancellable,

         GError                   **error)

{

  GProxyAddressEnumeratorPrivate *priv = GET_PRIVATE (enumerator);

  GSocketAddress *result = NULL;

  GError *first_error = NULL;

  if (!priv->ever_enumerated)

    {

      g_assert (priv->proxies == NULL);

      priv->proxies = g_proxy_resolver_lookup (priv->proxy_resolver,

                 priv->dest_uri,

                 cancellable,

                 error);

      priv->next_proxy = priv->proxies;

      if (priv->proxies == NULL)

  {

    priv->ever_enumerated = TRUE;

    return NULL;

  }

    }

  while (result == NULL && (*priv->next_proxy || priv->addr_enum))

    {

      gchar *dest_hostname;

      gchar *dest_protocol;

      GInetSocketAddress *inetsaddr;

      GInetAddress *inetaddr;

      guint16 port;

      next_enumerator (priv);

      if (!priv->addr_enum)

  continue;

      if (priv->proxy_address == NULL)

  {

    priv->proxy_address = g_socket_address_enumerator_next (

            priv->addr_enum,

            cancellable,

            first_error ? NULL : &first_error);

  }

      if (priv->proxy_address == NULL)

  {

    g_object_unref (priv->addr_enum);

    priv->addr_enum = NULL;

    if (priv->dest_ips)

      {

        g_resolver_free_addresses (priv->dest_ips);

        priv->dest_ips = NULL;

      }

    continue;

  }

      if (strcmp ("direct", priv->proxy_type) == 0)

  {

    result = priv->proxy_address;

    priv->proxy_address = NULL;

    continue;

  }

      if (!priv->supports_hostname)

  {

    GInetAddress *dest_ip;

    if (!priv->dest_ips)

      {

        GResolver *resolver;

        resolver = g_resolver_get_default();

        priv->dest_ips = g_resolver_lookup_by_name (resolver,

                priv->dest_hostname,

                cancellable,

                first_error ? NULL : &first_error);

        g_object_unref (resolver);

        if (!priv->dest_ips)

    {

      g_object_unref (priv->proxy_address);

      priv->proxy_address = NULL;

      continue;

    }

      }

    if (!priv->next_dest_ip)

      priv->next_dest_ip = priv->dest_ips;

    dest_ip = G_INET_ADDRESS (priv->next_dest_ip->data);

    dest_hostname = g_inet_address_to_string (dest_ip);

    priv->next_dest_ip = g_list_next (priv->next_dest_ip);

  }

      else

  {

    dest_hostname = g_strdup (priv->dest_hostname);

  }

      g_assert (G_IS_INET_SOCKET_ADDRESS (priv->proxy_address));

      dest_protocol = g_uri_parse_scheme (priv->dest_uri);

      inetsaddr = G_INET_SOCKET_ADDRESS (priv->proxy_address);

      inetaddr = g_inet_socket_address_get_address (inetsaddr);

      port = g_inet_socket_address_get_port (inetsaddr);

      result = g_object_new (G_TYPE_PROXY_ADDRESS,

           "address", inetaddr,

           "port", port,

           "protocol", priv->proxy_type,

           "destination-protocol", dest_protocol,

           "destination-hostname", dest_hostname,

           "destination-port", priv->dest_port,

           "username", priv->proxy_username,

           "password", priv->proxy_password,

           "uri", priv->proxy_uri,

           NULL);

      g_free (dest_hostname);

      g_free (dest_protocol);

      if (priv->supports_hostname || priv->next_dest_ip == NULL)

  {

    g_object_unref (priv->proxy_address);

    priv->proxy_address = NULL;

  }

    }

  if (result == NULL && first_error && (!priv->ever_enumerated || g_error_matches (first_error, G_IO_ERROR, G_IO_ERROR_CANCELLED)))

    g_propagate_error (error, first_error);

  else if (first_error)

    g_error_free (first_error);

  if (result == NULL && error != NULL && *error == NULL && !priv->ever_enumerated)

    g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED, _("Unspecified proxy lookup failure"));

  priv->ever_enumerated = TRUE;

  return result;

}

static void

complete_async (GTask *task)

{

  GProxyAddressEnumeratorPrivate *priv = g_task_get_task_data (task);

  if (priv->last_error && (!priv->ever_enumerated || g_error_matches (priv->last_error, G_IO_ERROR, G_IO_ERROR_CANCELLED)))

    {

      g_task_return_error (task, priv->last_error);

      priv->last_error = NULL;

    }

  else if (!priv->ever_enumerated)

    {

      g_task_return_new_error_literal (task, G_IO_ERROR, G_IO_ERROR_FAILED,

                                       _("Unspecified proxy lookup failure"));

    }

  else

    {

      g_task_return_pointer (task, NULL, NULL);

    }

  priv->ever_enumerated = TRUE;

  g_clear_error (&priv->last_error);

  g_object_unref (task);

}

static void

return_result (GTask *task)

{

  GProxyAddressEnumeratorPrivate *priv = g_task_get_task_data (task);

  GSocketAddress *result;

  if (strcmp ("direct", priv->proxy_type) == 0)

    {

      result = priv->proxy_address;

      priv->proxy_address = NULL;

    }

  else

    {

      gchar *dest_hostname, *dest_protocol;

      GInetSocketAddress *inetsaddr;

      GInetAddress *inetaddr;

      guint16 port;

      if (!priv->supports_hostname)

  {

    GInetAddress *dest_ip;

    if (!priv->next_dest_ip)

      priv->next_dest_ip = priv->dest_ips;

    dest_ip = G_INET_ADDRESS (priv->next_dest_ip->data);

    dest_hostname = g_inet_address_to_string (dest_ip);

    priv->next_dest_ip = g_list_next (priv->next_dest_ip);

  }

      else

  {

    dest_hostname = g_strdup (priv->dest_hostname);

  }

      dest_protocol = g_uri_parse_scheme (priv->dest_uri);

      g_assert (G_IS_INET_SOCKET_ADDRESS (priv->proxy_address));

      inetsaddr = G_INET_SOCKET_ADDRESS (priv->proxy_address);

      inetaddr = g_inet_socket_address_get_address (inetsaddr);

      port = g_inet_socket_address_get_port (inetsaddr);

      result = g_object_new (G_TYPE_PROXY_ADDRESS,

           "address", inetaddr,

           "port", port,

           "protocol", priv->proxy_type,

           "destination-protocol", dest_protocol,

           "destination-hostname", dest_hostname,

           "destination-port", priv->dest_port,

           "username", priv->proxy_username,

           "password", priv->proxy_password,

           "uri", priv->proxy_uri,

           NULL);

      g_free (dest_hostname);

      g_free (dest_protocol);

      if (priv->supports_hostname || priv->next_dest_ip == NULL)

  {

    g_object_unref (priv->proxy_address);

    priv->proxy_address = NULL;

  }

    }

  priv->ever_enumerated = TRUE;

  g_task_return_pointer (task, result, g_object_unref);

  g_object_unref (task);

}

static void address_enumerate_cb (GObject      *object,

          GAsyncResult *result,

          gpointer  user_data);

static void

next_proxy (GTask *task)

{

  GProxyAddressEnumeratorPrivate *priv = g_task_get_task_data (task);

  if (*priv->next_proxy)

    {

      g_object_unref (priv->addr_enum);

      priv->addr_enum = NULL;

      if (priv->dest_ips)

  {

    g_resolver_free_addresses (priv->dest_ips);

    priv->dest_ips = NULL;

  }

      next_enumerator (priv);

      if (priv->addr_enum)

  {

    g_socket_address_enumerator_next_async (priv->addr_enum,

              g_task_get_cancellable (task),

              address_enumerate_cb,

              task);

    return;

  }

    }

  complete_async (task);

}

static void

dest_hostname_lookup_cb (GObject           *object,

       GAsyncResult      *result,

       gpointer           user_data)

{

  GTask *task = user_data;

  GProxyAddressEnumeratorPrivate *priv = g_task_get_task_data (task);

  g_clear_error (&priv->last_error);

  priv->dest_ips = g_resolver_lookup_by_name_finish (G_RESOLVER (object),

                 result,

                 &priv->last_error);

  if (priv->dest_ips)

    return_result (task);

  else

    {

      g_clear_object (&priv->proxy_address);

      next_proxy (task);

    }

}

static void

address_enumerate_cb (GObject    *object,

          GAsyncResult *result,

          gpointer      user_data)

{

  GTask *task = user_data;

  GProxyAddressEnumeratorPrivate *priv = g_task_get_task_data (task);

  g_clear_error (&priv->last_error);

  priv->proxy_address =

    g_socket_address_enumerator_next_finish (priv->addr_enum,

               result,

               &priv->last_error);

  if (priv->proxy_address)

    {

      if (!priv->supports_hostname && !priv->dest_ips)

  {

    GResolver *resolver;

    resolver = g_resolver_get_default();

    g_resolver_lookup_by_name_async (resolver,

             priv->dest_hostname,

             g_task_get_cancellable (task),

             dest_hostname_lookup_cb,

             task);

    g_object_unref (resolver);

    return;

  }

      return_result (task);

    }

  else

    next_proxy (task);

}

static void

proxy_lookup_cb (GObject      *object,

     GAsyncResult *result,

     gpointer      user_data)

{

  GTask *task = user_data;

  GProxyAddressEnumeratorPrivate *priv = g_task_get_task_data (task);

  g_clear_error (&priv->last_error);

  priv->proxies = g_proxy_resolver_lookup_finish (G_PROXY_RESOLVER (object),

              result,

              &priv->last_error);

  priv->next_proxy = priv->proxies;

  if (priv->last_error)

    {

      complete_async (task);

      return;

    }

  else

    {

      next_enumerator (priv);

      if (priv->addr_enum)

  {

    g_socket_address_enumerator_next_async (priv->addr_enum,

              g_task_get_cancellable (task),

              address_enumerate_cb,

              task);

    return;

  }

    }

  complete_async (task);

}

static void

g_proxy_address_enumerator_next_async (GSocketAddressEnumerator *enumerator,

               GCancellable             *cancellable,

               GAsyncReadyCallback       callback,

               gpointer                  user_data)

{

  GProxyAddressEnumeratorPrivate *priv = GET_PRIVATE (enumerator);

  GTask *task;

  task = g_task_new (enumerator, cancellable, callback, user_data);

  g_task_set_source_tag (task, g_proxy_address_enumerator_next_async);

  g_task_set_task_data (task, priv, NULL);

  if (priv->proxies == NULL)

    {

      g_proxy_resolver_lookup_async (priv->proxy_resolver,

             priv->dest_uri,

             cancellable,

             proxy_lookup_cb,

             task);

      return;

    }

  if (priv->addr_enum)

    {

      if (priv->proxy_address)

  {

    return_result (task);

    return;

  }

      else

  {

    g_socket_address_enumerator_next_async (priv->addr_enum,

              cancellable,

              address_enumerate_cb,

              task);

    return;

  }

    }

  complete_async (task);

}

static GSocketAddress *

g_proxy_address_enumerator_next_finish (GSocketAddressEnumerator  *enumerator,

          GAsyncResult              *result,

          GError                   **error)

{

  g_return_val_if_fail (g_task_is_valid (result, enumerator), NULL);

  return g_task_propagate_pointer (G_TASK (result), error);

}

static void

g_proxy_address_enumerator_constructed (GObject *object)

{

  GProxyAddressEnumeratorPrivate *priv = GET_PRIVATE (object);

  GSocketConnectable *conn;

  guint port;

  if (priv->dest_uri)

    {

      conn = g_network_address_parse_uri (priv->dest_uri, priv->default_port, NULL);

      if (conn)

        {

          g_object_get (conn,

                        "hostname", &priv->dest_hostname,

                        "port", &port,

                        NULL);

          priv->dest_port = port;

          g_object_unref (conn);

        }

      else

        g_warning ("Invalid URI '%s'", priv->dest_uri);

    }

  G_OBJECT_CLASS (g_proxy_address_enumerator_parent_class)->constructed (object);

}

static void

g_proxy_address_enumerator_get_property (GObject        *object,

                                         guint           property_id,

                                         GValue         *value,

                                         GParamSpec     *pspec)

{

  GProxyAddressEnumeratorPrivate *priv = GET_PRIVATE (object);

  switch (property_id)

    {

    case PROP_URI:

      g_value_set_string (value, priv->dest_uri);

      break;

    case PROP_DEFAULT_PORT:

      g_value_set_uint (value, priv->default_port);

      break;

    case PROP_CONNECTABLE:

      g_value_set_object (value, priv->connectable);

      break;

    case PROP_PROXY_RESOLVER:

      g_value_set_object (value, priv->proxy_resolver);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);

    }

}

static void

g_proxy_address_enumerator_set_property (GObject        *object,

                                         guint           property_id,

                                         const GValue   *value,

                                         GParamSpec     *pspec)

{

  GProxyAddressEnumeratorPrivate *priv = GET_PRIVATE (object);

  switch (property_id)

    {

    case PROP_URI:

      priv->dest_uri = g_value_dup_string (value);

      break;

    case PROP_DEFAULT_PORT:

      priv->default_port = g_value_get_uint (value);

      break;

    case PROP_CONNECTABLE:

      priv->connectable = g_value_dup_object (value);

      break;

    case PROP_PROXY_RESOLVER:

      if (priv->proxy_resolver)

        g_object_unref (priv->proxy_resolver);

      priv->proxy_resolver = g_value_get_object (value);

      if (!priv->proxy_resolver)

        priv->proxy_resolver = g_proxy_resolver_get_default ();

      g_object_ref (priv->proxy_resolver);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);

    }

}

static void

g_proxy_address_enumerator_finalize (GObject *object)

{

  GProxyAddressEnumeratorPrivate *priv = GET_PRIVATE (object);

  if (priv->connectable)

    g_object_unref (priv->connectable);

  if (priv->proxy_resolver)

    g_object_unref (priv->proxy_resolver);

  g_free (priv->dest_uri);

  g_free (priv->dest_hostname);

  if (priv->dest_ips)

    g_resolver_free_addresses (priv->dest_ips);

  g_strfreev (priv->proxies);

  if (priv->addr_enum)

    g_object_unref (priv->addr_enum);

  g_free (priv->proxy_type);

  g_free (priv->proxy_username);

  g_free (priv->proxy_password);

  g_clear_error (&priv->last_error);

  G_OBJECT_CLASS (g_proxy_address_enumerator_parent_class)->finalize (object);

}

static void

g_proxy_address_enumerator_init (GProxyAddressEnumerator *self)

{

  self->priv = g_proxy_address_enumerator_get_instance_private (self);

}

static void

g_proxy_address_enumerator_class_init (GProxyAddressEnumeratorClass *proxy_enumerator_class)

{

  GObjectClass *object_class = G_OBJECT_CLASS (proxy_enumerator_class);

  GSocketAddressEnumeratorClass *enumerator_class = G_SOCKET_ADDRESS_ENUMERATOR_CLASS (proxy_enumerator_class);

  object_class->constructed = g_proxy_address_enumerator_constructed;

  object_class->set_property = g_proxy_address_enumerator_set_property;

  object_class->get_property = g_proxy_address_enumerator_get_property;

  object_class->finalize = g_proxy_address_enumerator_finalize;

  enumerator_class->next = g_proxy_address_enumerator_next;

  enumerator_class->next_async = g_proxy_address_enumerator_next_async;

  enumerator_class->next_finish = g_proxy_address_enumerator_next_finish;

  /**

   * GProxyAddressEnumerator:uri:

   *

   * The destination URI. Use `none://` for a generic socket.

   */

  g_object_class_install_property (object_class,

           PROP_URI,

           g_param_spec_string ("uri", NULL, NULL,

              NULL,

              G_PARAM_READWRITE |

              G_PARAM_CONSTRUCT_ONLY |

              G_PARAM_STATIC_STRINGS));

  /**

   * GProxyAddressEnumerator:default-port:

   *

   * The default port to use if #GProxyAddressEnumerator:uri does not

   * specify one.

   *

   * Since: 2.38

   */

  g_object_class_install_property (object_class,

           PROP_DEFAULT_PORT,

           g_param_spec_uint ("default-port", NULL, NULL,

                                                      0, 65535, 0,

                                                      G_PARAM_READWRITE |

                                                      G_PARAM_CONSTRUCT_ONLY |

                                                      G_PARAM_STATIC_STRINGS));

  /**

   * GProxyAddressEnumerator:connectable:

   *

   * The connectable being enumerated.

   */

  g_object_class_install_property (object_class,

           PROP_CONNECTABLE,

           g_param_spec_object ("connectable", NULL, NULL,

              G_TYPE_SOCKET_CONNECTABLE,

              G_PARAM_READWRITE |

              G_PARAM_CONSTRUCT_ONLY |

              G_PARAM_STATIC_STRINGS));

  /**

   * GProxyAddressEnumerator:proxy-resolver:

   *

   * The proxy resolver to use.

   *

   * Since: 2.36

   */

  g_object_class_install_property (object_class,

                                   PROP_PROXY_RESOLVER,

                                   g_param_spec_object ("proxy-resolver", NULL, NULL,

                                                        G_TYPE_PROXY_RESOLVER,

                                                        G_PARAM_READWRITE |

                                                        G_PARAM_CONSTRUCT |

                                                        G_PARAM_STATIC_STRINGS));

}