Commit c1e32b90 authored by Patrick Griffis's avatar Patrick Griffis Committed by Patrick Griffis

gsocketclient: Improve handling of slow initial connections

Currently a new connection will not be attempted until the previous
one has timed out and as the current API only exposes a single
timeout value in practice it often means that it will wait 30 seconds
(or forever with 0 (the default)) on each connection.

This is unacceptable so we are now trying to follow the behavior
RFC 8305 recommends by making multiple connection attempts if
the connection takes longer than 250ms. The first connection
to make it to completion then wins.
parent 35e41862
......@@ -2,6 +2,7 @@
*
* Copyright © 2008, 2009 codethink
* Copyright © 2009 Red Hat, Inc
* Copyright © 2018 Igalia S.L.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
......@@ -49,6 +50,10 @@
#include <gio/ginetaddress.h>
#include "glibintl.h"
/* As recommended by RFC 8305 this is the time it waits
* on a connection before starting another concurrent attempt.
*/
#define HAPPY_EYEBALLS_CONNECTION_ATTEMPT_TIMEOUT_MS 250
/**
* SECTION:gsocketclient
......@@ -1328,28 +1333,82 @@ typedef struct
GSocketConnectable *connectable;
GSocketAddressEnumerator *enumerator;
GProxyAddress *proxy_addr;
GSocketAddress *current_addr;
GSocket *current_socket;
GSocket *socket;
GIOStream *connection;
GSList *connection_attempts;
GError *last_error;
} GSocketClientAsyncConnectData;
static void connection_attempt_unref (gpointer attempt);
static void
g_socket_client_async_connect_data_free (GSocketClientAsyncConnectData *data)
{
g_clear_object (&data->connectable);
g_clear_object (&data->enumerator);
g_clear_object (&data->proxy_addr);
g_clear_object (&data->current_addr);
g_clear_object (&data->current_socket);
g_clear_object (&data->socket);
g_clear_object (&data->connection);
g_slist_free_full (data->connection_attempts, connection_attempt_unref);
g_clear_error (&data->last_error);
g_slice_free (GSocketClientAsyncConnectData, data);
}
typedef struct
{
GSocketAddress *address;
GSocket *socket;
GIOStream *connection;
GSocketClientAsyncConnectData *data; /* unowned */
GSource *timeout_source;
GCancellable *cancellable;
grefcount ref;
} ConnectionAttempt;
static ConnectionAttempt *
connection_attempt_new (void)
{
ConnectionAttempt *attempt = g_new0 (ConnectionAttempt, 1);
g_ref_count_init (&attempt->ref);
return attempt;
}
static ConnectionAttempt *
connection_attempt_ref (ConnectionAttempt *attempt)
{
g_ref_count_inc (&attempt->ref);
return attempt;
}
static void
connection_attempt_unref (gpointer pointer)
{
ConnectionAttempt *attempt = pointer;
if (g_ref_count_dec (&attempt->ref))
{
g_clear_object (&attempt->address);
g_clear_object (&attempt->socket);
g_clear_object (&attempt->connection);
g_clear_object (&attempt->cancellable);
if (attempt->timeout_source)
{
g_source_destroy (attempt->timeout_source);
g_source_unref (attempt->timeout_source);
}
g_free (attempt);
}
}
static void
connection_attempt_remove (ConnectionAttempt *attempt)
{
attempt->data->connection_attempts = g_slist_remove (attempt->data->connection_attempts, attempt);
connection_attempt_unref (attempt);
}
static void
g_socket_client_async_connect_complete (GSocketClientAsyncConnectData *data)
{
......@@ -1359,8 +1418,7 @@ g_socket_client_async_connect_complete (GSocketClientAsyncConnectData *data)
{
GSocketConnection *wrapper_connection;
wrapper_connection = g_tcp_wrapper_connection_new (data->connection,
data->current_socket);
wrapper_connection = g_tcp_wrapper_connection_new (data->connection, data->socket);
g_object_unref (data->connection);
data->connection = (GIOStream *)wrapper_connection;
}
......@@ -1389,8 +1447,7 @@ static void
enumerator_next_async (GSocketClientAsyncConnectData *data)
{
/* We need to cleanup the state */
g_clear_object (&data->current_socket);
g_clear_object (&data->current_addr);
g_clear_object (&data->socket);
g_clear_object (&data->proxy_addr);
g_clear_object (&data->connection);
......@@ -1485,34 +1542,68 @@ g_socket_client_connected_callback (GObject *source,
GAsyncResult *result,
gpointer user_data)
{
GSocketClientAsyncConnectData *data = user_data;
ConnectionAttempt *attempt = user_data;
GSocketClientAsyncConnectData *data = attempt->data;
GSList *l;
GError *error = NULL;
GProxy *proxy;
const gchar *protocol;
if (g_task_return_error_if_cancelled (data->task))
/* data is NULL once the task is completed */
if (data && g_task_return_error_if_cancelled (data->task))
{
g_object_unref (data->task);
connection_attempt_unref (attempt);
return;
}
if (attempt->timeout_source)
{
g_source_destroy (attempt->timeout_source);
g_clear_pointer (&attempt->timeout_source, g_source_unref);
}
if (!g_socket_connection_connect_finish (G_SOCKET_CONNECTION (source),
result, &error))
{
clarify_connect_error (error, data->connectable,
data->current_addr);
set_last_error (data, error);
if (!g_cancellable_is_cancelled (attempt->cancellable))
{
clarify_connect_error (error, data->connectable, attempt->address);
set_last_error (data, error);
}
else
g_clear_error (&error);
if (data)
{
connection_attempt_remove (attempt);
enumerator_next_async (data);
}
else
connection_attempt_unref (attempt);
/* try next one */
enumerator_next_async (data);
return;
}
data->socket = g_steal_pointer (&attempt->socket);
data->connection = g_steal_pointer (&attempt->connection);
for (l = data->connection_attempts; l; l = g_slist_next (l))
{
ConnectionAttempt *attempt_entry = l->data;
g_cancellable_cancel (attempt_entry->cancellable);
attempt_entry->data = NULL;
connection_attempt_unref (attempt_entry);
}
g_slist_free (data->connection_attempts);
data->connection_attempts = NULL;
connection_attempt_unref (attempt);
g_socket_connection_set_cached_remote_address ((GSocketConnection*)data->connection, NULL);
g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_CONNECTED, data->connectable, data->connection);
/* wrong, but backward compatible */
g_socket_set_blocking (data->current_socket, TRUE);
g_socket_set_blocking (data->socket, TRUE);
if (!data->proxy_addr)
{
......@@ -1565,6 +1656,26 @@ g_socket_client_connected_callback (GObject *source,
}
}
static gboolean
on_connection_attempt_timeout (gpointer data)
{
ConnectionAttempt *attempt = data;
enumerator_next_async (attempt->data);
g_clear_pointer (&attempt->timeout_source, g_source_unref);
return G_SOURCE_REMOVE;
}
static void
on_connection_cancelled (GCancellable *cancellable,
gpointer data)
{
GCancellable *attempt_cancellable = data;
g_cancellable_cancel (attempt_cancellable);
}
static void
g_socket_client_enumerator_callback (GObject *object,
GAsyncResult *result,
......@@ -1573,6 +1684,7 @@ g_socket_client_enumerator_callback (GObject *object,
GSocketClientAsyncConnectData *data = user_data;
GSocketAddress *address = NULL;
GSocket *socket;
ConnectionAttempt *attempt;
GError *error = NULL;
if (g_task_return_error_if_cancelled (data->task))
......@@ -1585,6 +1697,9 @@ g_socket_client_enumerator_callback (GObject *object,
result, &error);
if (address == NULL)
{
if (data->connection_attempts)
return;
g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_COMPLETE, data->connectable, NULL);
if (!error)
{
......@@ -1621,16 +1736,27 @@ g_socket_client_enumerator_callback (GObject *object,
return;
}
data->current_socket = socket;
data->current_addr = address;
data->connection = (GIOStream *) g_socket_connection_factory_create_connection (socket);
g_socket_connection_set_cached_remote_address ((GSocketConnection*)data->connection, address);
g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_CONNECTING, data->connectable, data->connection);
g_socket_connection_connect_async (G_SOCKET_CONNECTION (data->connection),
attempt = connection_attempt_new ();
attempt->data = data;
attempt->socket = socket;
attempt->address = address;
attempt->cancellable = g_cancellable_new ();
attempt->connection = (GIOStream *)g_socket_connection_factory_create_connection (socket);
attempt->timeout_source = g_timeout_source_new (HAPPY_EYEBALLS_CONNECTION_ATTEMPT_TIMEOUT_MS);
g_source_set_callback (attempt->timeout_source, on_connection_attempt_timeout, attempt, NULL);
g_source_attach (attempt->timeout_source, g_main_context_get_thread_default ());
data->connection_attempts = g_slist_append (data->connection_attempts, attempt);
if (g_task_get_cancellable (data->task))
g_cancellable_connect (g_task_get_cancellable (data->task), G_CALLBACK (on_connection_cancelled),
g_object_ref (attempt->cancellable), g_object_unref);
g_socket_connection_set_cached_remote_address ((GSocketConnection *)attempt->connection, address);
g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_CONNECTING, data->connectable, attempt->connection);
g_socket_connection_connect_async (G_SOCKET_CONNECTION (attempt->connection),
address,
g_task_get_cancellable (data->task),
g_socket_client_connected_callback, data);
attempt->cancellable,
g_socket_client_connected_callback, connection_attempt_ref (attempt));
}
/**
......
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