path: root/src/lacconnection.c

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- */

/*  Lac - Library for asynchronous communication
 *  Copyright (C) 2000, 2001, 2002, 2003  Søren Sandmann
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the 
 *  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 *  Boston, MA  02111-1307, USA.
 */

#include "lac.h"
#include <string.h>

/*
 * Prototypes for a primitive abstraction covering TCP and SSL
 */

typedef struct Socket Socket;

static Socket * socket_new_tcp      (GError            **err);
static Socket * socket_new_ssl      (GError            **err);
static gboolean socket_connect      (Socket             *socket,
                                     LacAddress         *address,
                                     gint                port,
                                     GError            **err);
static gboolean socket_is_connected (Socket             *socket);
static gint     socket_send         (Socket             *socket,
                                     const guint8       *msg,
                                     guint               len,
                                     GError            **err);
static gint     socket_recv         (Socket             *socket,
                                     guint8             *buf,
                                     guint               size,
                                     GError            **err);
#if 0
static int      socket_get_fd       (Socket             *socket);
#endif
static void     socket_flush        (Socket             *socket);
static gboolean socket_shutdown     (Socket             *socket,
                                     LacShutdownMethod   how,
                                     GError            **err);
static gboolean socket_set_blocking (Socket             *socket,
                                     gboolean            blocking,
                                     GError            **err);
static gboolean socket_close        (Socket             *socket,
                                     GError            **err);
static void     socket_add_watch    (Socket             *socket,
                                     gpointer            data);
static void     socket_remove_watch (Socket             *socket);
static void     socket_set_read_cb  (Socket           *socket,
                                     LacWatchCallback  read_cb);
static void     socket_set_write_cb (Socket           *socket,
                                     LacWatchCallback  write_cb);


typedef enum {
    UNDEFINED,
    CONNECT_IN_PROGRESS,
    CONNECTED,
    DISCONNECTED,
} ConnectionState;

struct _LacConnection {
    Socket *            socket;
    LacAddress *        address;
    gint                port;
    LacConnectionFunc   callback;
    gpointer            data;

    GQueue *            pending_events;
    
    ConnectionState     state;
    LacByteQueue *      unwritten;
    
    gboolean            has_fd;
    gboolean            write_shutdown;
    gboolean            in_emit_events;
    gboolean            need_flush;
    gint                ref_count;
};


static void
event_free (LacConnectionEvent *event)
{
    if (event->type == LAC_CONNECTION_EVENT_READ)
        g_free ((gchar *)event->read.data);
    else if (event->type == LAC_CONNECTION_EVENT_ERROR)
        g_error_free ((GError *)event->error.err);
    
    g_free (event);
}

static void
queue_connect (LacConnection *connection)
{
    LacConnectionEvent *event = g_new (LacConnectionEvent, 1);

    event->type = LAC_CONNECTION_EVENT_CONNECT;

    g_queue_push_tail (connection->pending_events, event);
}

static void
queue_read (LacConnection *connection, const guint8 *data, guint len)
{
    LacConnectionEvent *event = g_new (LacConnectionEvent, 1);
    
    event->type = LAC_CONNECTION_EVENT_READ;
    event->read.data = g_memdup (data, len);
    event->read.len = len;

    g_queue_push_tail (connection->pending_events, event);
}

static void
queue_close (LacConnection *connection, gboolean remote)
{
    LacConnectionEvent *event = g_new (LacConnectionEvent, 1);

    event->type = LAC_CONNECTION_EVENT_CLOSE;
    event->close.remote_closed = remote;

    g_queue_push_tail (connection->pending_events, event);
}

static void
queue_error (LacConnection *connection, const GError *err)
{
    LacConnectionEvent *event = g_new (LacConnectionEvent, 1);
    
    event->type = LAC_CONNECTION_EVENT_ERROR;
    event->error.err = g_error_copy (err);

    g_queue_push_tail (connection->pending_events, event);
}

static void
emit_events (LacConnection *connection)
{
    LacConnectionEvent *event;

    if (connection->in_emit_events)
        return;

    connection->in_emit_events = TRUE;
    lac_connection_ref (connection);

    while ((event = g_queue_pop_head (connection->pending_events)))
    {
        if (connection->state != DISCONNECTED)
        {
            if (event->type == LAC_CONNECTION_EVENT_CLOSE ||
                event->type == LAC_CONNECTION_EVENT_ERROR)
            {
                connection->state = DISCONNECTED;

                if (connection->has_fd)
                {
                    socket_remove_watch (connection->socket);
                    socket_close (connection->socket, NULL);
                    connection->has_fd = FALSE;
                }
            }
            
            connection->callback (connection, event);
        }
        
        event_free (event);
    }

    connection->in_emit_events = FALSE;
    lac_connection_unref (connection);
}

static gboolean
emit_events_idle_handler (gpointer data)
{
    LacConnection *connection = data;
    emit_events (connection);

    lac_connection_unref (connection);

    return FALSE; /* don't call me again */
}

static void
emit_events_idle (LacConnection *connection)
{
    if (!g_queue_is_empty (connection->pending_events))
    {
        g_idle_add (
            emit_events_idle_handler, lac_connection_ref (connection));
    }
}

static void
lac_connection_do_reads (gpointer data)
{
    LacConnection *connection = data;
    gint len;
    
    enum { BUF_SIZE = 8280 };

    do
    {
        guint8 buf [BUF_SIZE];
        GError *err = NULL;
        
        len = socket_recv (connection->socket, buf, BUF_SIZE, &err);
        if (len < 0)
        {
            g_assert (err);
            
            if (!g_error_matches (
                    err, LAC_SOCKET_ERROR, LAC_SOCKET_ERROR_AGAIN))
            {
                queue_error (connection, err);
            }

            g_error_free (err);
        }
        else if (len == 0)
        {
            queue_close (connection, TRUE);
        }
        else
        {
            queue_read (connection, buf, len);
        }

        /* FIXME: check that we haven't used too much time? */
    }
    while (len == BUF_SIZE);
}

static void lac_connection_writable (gpointer data);

static void
lac_connection_do_writes (LacConnection *connection)
{
    if (connection->state != CONNECTED)
    {
        socket_set_write_cb (connection->socket, lac_connection_writable);
        return;
    }
    
    while (lac_byte_queue_get_length (connection->unwritten) > 0)
    {
        GError       *err = NULL;
        const guint8 *unwritten;
        gsize         len, sent;
        
        unwritten = lac_byte_queue_get_data (connection->unwritten, &len);

        sent = socket_send (connection->socket, unwritten, len, &err);

        lac_byte_queue_append (
            connection->unwritten, unwritten, err? len : len - sent);
        
        if (err)
        {
            lac_byte_queue_append (connection->unwritten, unwritten, len);
            
            if (g_error_matches (
                err, LAC_SOCKET_ERROR, LAC_SOCKET_ERROR_AGAIN))
            {
                socket_set_write_cb (
                    connection->socket, lac_connection_writable);
            }
            else
            {
                queue_error (connection, err);
            }

            g_error_free (err);
            return;
        }

        /* FIXME check that we haven't used too much time? */
    }

    socket_set_write_cb (connection->socket, NULL);
    
    if (connection->need_flush)
    {
        socket_flush (connection->socket);

        connection->need_flush = FALSE;
    }

    if (connection->write_shutdown)
    {
        GError *err = NULL;
        
        socket_shutdown (connection->socket, LAC_SHUTDOWN_WRITE, &err);
        if (err)
        {
            queue_error (connection, err);
            g_error_free (err);
        }
    }
}

static void
lac_connection_readable (gpointer data)
{
    LacConnection *connection = data;
    
    lac_connection_do_reads (connection);
    emit_events (connection);
}

static void
lac_connection_writable (gpointer data)
{
    LacConnection *connection = data;
    
    if (connection->state == CONNECT_IN_PROGRESS)
    {
        if (!socket_is_connected (connection->socket))
            return;
        
        connection->state = CONNECTED;
        queue_connect (connection);
    }

    lac_connection_do_writes (connection);
    emit_events (connection);
}

static void
lac_connection_connect (LacConnection *connection)
{
    GError *err = NULL;
    
    socket_connect (connection->socket,
                    connection->address, connection->port,
                    &err);

    if (err)
    {
        if (g_error_matches (
            err, LAC_SOCKET_ERROR, LAC_SOCKET_ERROR_IN_PROGRESS))
        {
            connection->state = CONNECT_IN_PROGRESS;
        }
        else
        {
            queue_error (connection, err);
        }

        g_error_free (err);
    }
    else
    {
        connection->state = CONNECTED;
        queue_connect (connection);
        lac_connection_do_writes (connection);
    }
}

static void
lac_connection_discard_pending_events (LacConnection *connection)
{
    LacConnectionEvent *event;

    while ((event = g_queue_pop_head (connection->pending_events)))
        event_free (event);
}

static void
lac_connection_add_watch (LacConnection *connection)
{
    socket_add_watch (connection->socket, connection);

    socket_set_read_cb (connection->socket, lac_connection_readable);
    socket_set_write_cb (connection->socket, lac_connection_writable);
}

LacConnection *
lac_connection_new (const LacAddress  *address,
                    gint               port,
                    LacConnectionFunc  callback,
                    gpointer           data)
{
    LacConnection *connection;
    GError *err = NULL;
    
    g_return_val_if_fail (address != NULL, NULL);
    g_return_val_if_fail (port > 0, NULL);
    g_return_val_if_fail (callback != NULL, NULL);
    
    connection = g_new (LacConnection, 1);
    
    connection->ref_count = 1;
    
    connection->address = lac_address_copy (address);
    connection->port = port;
    connection->callback = callback;
    connection->data = data;

    connection->pending_events = g_queue_new ();
    
    connection->state = UNDEFINED;
    connection->has_fd = FALSE;
    connection->unwritten = lac_byte_queue_new ();
    
    connection->write_shutdown = FALSE;
    connection->in_emit_events = FALSE;
    connection->need_flush = FALSE;
        
    connection->socket = socket_new_tcp (&err);
    if (err)
    {
        queue_error (connection, err);
        emit_events_idle (connection);
        g_error_free (err);
        return connection;
    }

    connection->has_fd = TRUE;
    
    socket_set_blocking (connection->socket, FALSE, &err);
    if (err)
    {
        queue_error (connection, err);
        emit_events_idle (connection);
        g_error_free (err);
        return connection;
    }

    lac_connection_add_watch (connection);
    lac_connection_connect (connection);

    emit_events_idle (connection);
    
    return connection;
}

gpointer
lac_connection_get_data (LacConnection     *connection)
{
    g_return_val_if_fail (connection != NULL, NULL);
    
    return connection->data;
}

void
lac_connection_write (LacConnection     *connection,
                      const guint8      *data,
                      guint              len)
{
    gboolean do_writes;

    g_return_if_fail (connection != NULL);
    g_return_if_fail (data != NULL);
    g_return_if_fail (!connection->write_shutdown);
    g_return_if_fail (connection->state != DISCONNECTED);

    if (len == 0)
        return;
    
    do_writes = (lac_byte_queue_get_length (connection->unwritten) == 0);

    lac_byte_queue_append (connection->unwritten, data, len);

    if (do_writes)
    {
        lac_connection_do_writes (connection);
        emit_events (connection);
    }
}

void
lac_connection_write_cstr (LacConnection     *connection,
                           const gchar       *data)
{
    guint len;
    
    g_return_if_fail (connection != NULL);
    g_return_if_fail (data != NULL);
    g_return_if_fail (!connection->write_shutdown);

    len = strlen (data);
    
    if (len > 0)
        lac_connection_write (connection, (const guint8 *)data, len);
}

void
lac_connection_shutdown_write (LacConnection     *connection)
{
    g_return_if_fail (connection != NULL);
    
    connection->write_shutdown = TRUE;

    lac_connection_do_writes (connection);
    emit_events (connection);
}

void
lac_connection_close (LacConnection    *connection)
{
    g_return_if_fail (connection != NULL);

    lac_connection_discard_pending_events (connection);

    queue_close (connection, FALSE);
    emit_events (connection);
}

LacConnection *
lac_connection_ref (LacConnection     *connection)
{
    ++connection->ref_count;
    
    return connection;
}

void
lac_connection_unref (LacConnection     *connection)
{
    if (--connection->ref_count == 0)
    {
        lac_address_free (connection->address);

        lac_connection_discard_pending_events (connection);
        g_queue_free (connection->pending_events);

        lac_byte_queue_free (connection->unwritten, TRUE);
        
        if (connection->has_fd)
        {
            socket_remove_watch (connection->socket);
            socket_close (connection->socket, NULL);
        }

        g_free (connection);
    }
}

G_CONST_RETURN LacAddress *
lac_connection_get_address (LacConnection     *connection)
{
    return connection->address;
}

gint
lac_connection_get_port    (LacConnection     *connection)
{
    return connection->port;
}

gboolean
lac_connection_is_connected (LacConnection *connection)
{
    return connection->state == CONNECTED;
}

void
lac_connection_flush (LacConnection     *connection)
{
    connection->need_flush = TRUE;

    if (lac_byte_queue_get_length (connection->unwritten) == 0)
        lac_connection_do_writes (connection);
}


/*
 * Socket abstraction
 */
struct Socket
{
    gboolean ssl;

    union
    {
        struct
        {
            int         fd;
        } tcp;

        struct
        {
            int                 fd;
            LacTLS             *tls;
            gboolean            override;
            gpointer            data;
            LacWatchCallback    read_cb;
            LacWatchCallback    write_cb;
        } ssl;
    } u;
};

static Socket *
socket_new_tcp (GError **err)
{
    Socket *socket;    
    int fd;

    fd = lac_socket_tcp (err);

    if (fd < 0)
        return NULL;
    
    socket = g_new0 (Socket, 1);
    socket->u.ssl.tls = FALSE;
    socket->u.ssl.fd = fd;
    socket->u.ssl.override = FALSE;
    socket->u.ssl.read_cb = NULL;
    socket->u.ssl.write_cb = NULL;
    
    return socket;
}

static Socket *
socket_new_ssl (GError **err)
{
    Socket *socket;
    int fd;

    fd = lac_socket_tcp (err);
    if (fd < 0)
        return NULL;

    socket = g_new0 (Socket, 1);
    socket->ssl = TRUE;
    socket->u.ssl.fd = fd;
    socket->u.ssl.tls = NULL; // lac_tls

    return socket;
}

static gboolean
socket_connect (Socket       *socket,
                LacAddress   *address,
                gint          port,
                GError      **err)
{
    if (socket->ssl)
    {
        lac_connect (socket->u.ssl.fd, address, port, err);
        
    }
    else
    {
        return lac_connect (socket->u.tcp.fd, address, port, err);
    }
}

static gboolean
socket_is_connected (Socket  *socket)
{
    /* We only get called when the fd is writable, which
     * for TCP sockets means it's connected
     */
    return TRUE;
}

static void
set_normal_callbacks (Socket *socket)
{
    g_assert (socket->ssl);
    
    lac_fd_set_read_callback (socket->u.ssl.fd, socket->u.ssl.read_cb);
    lac_fd_set_write_callback (socket->u.ssl.fd, socket->u.ssl.write_cb);

    socket->u.ssl.override = FALSE;
}

static void
override_readable (gpointer data)
{
    Socket *socket = data;

    if (socket->u.ssl.read_cb)
        socket->u.ssl.read_cb (socket->u.ssl.data);

    set_normal_callbacks (socket);
}

static void
override_writable (gpointer data)
{
    Socket *socket = data;

    if (socket->u.ssl.write_cb)
        socket->u.ssl.write_cb (socket->u.ssl.data);

    set_normal_callbacks (socket);
}

static gboolean
lactls_needs_write (LacTLS *tls)
{
    return FALSE;
}

static void
override_callbacks (Socket           *socket,
                    LacWatchCallback  func)
{
    gboolean needs_write;
    
    g_assert (socket->ssl);

    needs_write = lactls_needs_write (socket->u.ssl.tls);

    lac_fd_set_write_callback (socket->u.ssl.fd, needs_write? func : NULL);
    lac_fd_set_read_callback (socket->u.ssl.fd, needs_write? NULL : func);

#if 0
    socket->u.ssl.overridden = TRUE;
#endif
}

static gint
socket_send (Socket       *socket,
             const guint8 *msg,
             guint         len,
             GError      **err)
{
    if (socket->ssl)
    {
        GError *err = NULL;
        
#if 0
        lac_tls_send (socket->u.ssl.tls, msg, len, &err);
#endif

        if (err)
        {
#if 0
            if (AGAIN)
                override_callbacks (socket, override_writable);
#endif
        }
    }
    else
    {
        return lac_send (socket->u.tcp.fd, msg, len, err);
    }
}

static gint
socket_recv (Socket       *socket,
             guint8       *buf,
             guint         size,
             GError      **err)
{
    if (socket->ssl)
    {
    }
    else
    {
        return lac_recv (socket->u.tcp.fd, (gchar *)buf, size, err);
    }
}

static gboolean
socket_close   (Socket       *socket,
                GError      **err)
{
    if (socket->ssl)
    {
    }
    else
    {
        return lac_close (socket->u.tcp.fd, err);
    }
}

static void
socket_flush (Socket *socket)
{
    if (socket->ssl)
    {
    }
    else
    {
        /* Turn Nagle off, then on, to make the kernel send everything it
         * has queued up.
         */
        
        lac_set_nagle (socket->u.tcp.fd, FALSE, NULL);
        lac_set_nagle (socket->u.tcp.fd, TRUE, NULL);
    }
    
}

static gboolean
socket_set_blocking (Socket             *socket,
                     gboolean            blocking,
                     GError            **err)
{
    if (socket->ssl)
    {
    }
    else
    {
        return lac_set_blocking (socket->u.tcp.fd, blocking, err);
    }
}

static gboolean
socket_shutdown (Socket *socket,
                 LacShutdownMethod   how,
                 GError **err)
{
    if (socket->ssl)
    {
    }
    else
    {
        return lac_shutdown (socket->u.tcp.fd, how, err);
    }
}

static void
socket_add_watch (Socket *socket,
                  gpointer data)
{
    if (socket->ssl)
    {
        socket->u.ssl.data = data;
        lac_fd_add_watch (socket->u.ssl.fd, data);
    }
    else
    {
        lac_fd_add_watch (socket->u.tcp.fd, data);
    }
}

static void
socket_remove_watch (Socket *socket)
{
    if (socket->ssl)
    {
        socket->u.ssl.data = NULL;
        lac_fd_remove_watch (socket->u.ssl.fd);
    }
    else
    {
        lac_fd_remove_watch (socket->u.tcp.fd);
    }
}

static void
socket_set_read_cb (Socket           *socket,
                    LacWatchCallback  read_cb)
{
    if (socket->ssl)
    {
    }
    else
    {
        lac_fd_set_read_callback (socket->u.tcp.fd, read_cb);
        lac_fd_set_hangup_callback (socket->u.tcp.fd, read_cb);
        lac_fd_set_error_callback (socket->u.tcp.fd, read_cb);
        lac_fd_set_write_callback (socket->u.tcp.fd, read_cb);
    }
}

static void
socket_set_write_cb (Socket           *socket,
                     LacWatchCallback  write_cb)
{
    if (socket->ssl)
    {
    }
    else
    {
        lac_fd_set_write_callback (socket->u.tcp.fd, write_cb);
    }
}