/****************************************************************************
* net/tcp/tcp_netpoll.c
*
* Copyright (C) 2008-2009, 2011-2016, 2018 Gregory Nutt. All rights
* reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <assert.h>
#include <poll.h>
#include <debug.h>
#include <nuttx/net/net.h>
#include <nuttx/semaphore.h>
#include "devif/devif.h"
#include "netdev/netdev.h"
#include "socket/socket.h"
#include "inet/inet.h"
#include "tcp/tcp.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_poll_eventhandler
*
* Description:
* This function is called to perform the actual TCP receive operation via
* the device interface layer.
*
* Input Parameters:
* dev The structure of the network driver that caused the event
* conn The connection structure associated with the socket
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked
*
****************************************************************************/
static uint16_t tcp_poll_eventhandler(FAR struct net_driver_s *dev,
FAR void *conn,
FAR void *pvpriv, uint16_t flags)
{
FAR struct tcp_poll_s *info = (FAR struct tcp_poll_s *)pvpriv;
ninfo("flags: %04x\n", flags);
DEBUGASSERT(info == NULL || (info->psock != NULL && info->fds != NULL));
/* 'priv' might be null in some race conditions (?) */
if (info != NULL)
{
pollevent_t eventset = 0;
/* Check for data or connection availability events. */
if ((flags & (TCP_NEWDATA | TCP_BACKLOG)) != 0)
{
eventset |= POLLIN & info->fds->events;
}
/* Check for a loss of connection events. */
if ((flags & TCP_DISCONN_EVENTS) != 0)
{
/* Mark that the connection has been lost */
tcp_lost_connection(info->psock, info->cb, flags);
eventset |= (POLLERR | POLLHUP);
}
/* A poll is a sign that we are free to send data. */
else if (psock_tcp_cansend(info->psock) >= 0)
{
eventset |= (POLLOUT & info->fds->events);
}
/* Awaken the caller of poll() if requested event occurred. */
if (eventset != 0)
{
/* Stop further callbacks */
info->cb->flags = 0;
info->cb->priv = NULL;
info->cb->event = NULL;
info->fds->revents |= eventset;
nxsem_post(info->fds->sem);
}
}
return flags;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_pollsetup
*
* Description:
* Setup to monitor events on one TCP/IP socket
*
* Input Parameters:
* psock - The TCP/IP socket of interest
* fds - The structure describing the events to be monitored, OR NULL if
* this is a request to stop monitoring events.
*
* Returned Value:
* 0: Success; Negated errno on failure
*
****************************************************************************/
int tcp_pollsetup(FAR struct socket *psock, FAR struct pollfd *fds)
{
FAR struct tcp_conn_s *conn = psock->s_conn;
FAR struct tcp_poll_s *info;
FAR struct devif_callback_s *cb;
int ret = OK;
/* Sanity check */
#ifdef CONFIG_DEBUG_FEATURES
if (!conn || !fds)
{
return -EINVAL;
}
#endif
/* Some of the following must be atomic */
net_lock();
/* Find a container to hold the poll information */
info = conn->pollinfo;
while (info->psock != NULL)
{
if (++info >= &conn->pollinfo[CONFIG_NET_TCP_NPOLLWAITERS])
{
ret = -ENOMEM;
goto errout_with_lock;
}
}
/* Allocate a TCP/IP callback structure */
cb = tcp_callback_alloc(conn);
if (!cb)
{
ret = -EBUSY;
goto errout_with_lock;
}
/* Initialize the poll info container */
info->psock = psock;
info->fds = fds;
info->cb = cb;
/* Initialize the callback structure. Save the reference to the info
* structure as callback private data so that it will be available during
* callback processing.
*/
cb->flags = TCP_DISCONN_EVENTS;
cb->priv = (FAR void *)info;
cb->event = tcp_poll_eventhandler;
if ((fds->events & POLLOUT) != 0)
{
cb->flags |= TCP_POLL;
}
if ((fds->events & POLLIN) != 0)
{
cb->flags |= TCP_NEWDATA | TCP_BACKLOG;
}
/* Save the reference in the poll info structure as fds private as well
* for use during poll teardown as well.
*/
fds->priv = (FAR void *)info;
/* Check for read data or backlogged connection availability now */
if (!IOB_QEMPTY(&conn->readahead) || tcp_backlogavailable(conn))
{
/* Normal data may be read without blocking. */
fds->revents |= (POLLRDNORM & fds->events);
}
/* Check for a loss of connection events. We need to be careful here.
* There are four possibilities:
*
* 1) The socket is connected and we are waiting for data availability
* events.
*
* __SS_ISCONNECTED(f) == true
* __SS_ISLISTENING(f) == false
* __SS_ISCLOSED(f) == false
*
* Action: Wait for data availability events
*
* 2) This is a listener socket that was never connected and we are
* waiting for connection events.
*
* __SS_ISCONNECTED(f) == false
* __SS_ISLISTENING(f) == true
* __SS_ISCLOSED(f) == false
*
* Action: Wait for connection events
*
* 3) This socket was previously connected, but the peer has gracefully
* closed the connection.
*
* __SS_ISCONNECTED(f) == false
* __SS_ISLISTENING(f) == false
* __SS_ISCLOSED(f) == true
*
* Action: Return with POLLHUP|POLLERR events
*
* 4) This socket was previously connected, but we lost the connection
* due to some exceptional event.
*
* __SS_ISCONNECTED(f) == false
* __SS_ISLISTENING(f) == false
* __SS_ISCLOSED(f) == false
*
* Action: Return with POLLHUP|POLLERR events
*/
if (!_SS_ISCONNECTED(psock->s_flags) && !_SS_ISLISTENING(psock->s_flags))
{
/* We were previously connected but lost the connection either due
* to a graceful shutdown by the remote peer or because of some
* exceptional event.
*/
fds->revents |= (POLLERR | POLLHUP);
}
else if (_SS_ISCONNECTED(psock->s_flags) && psock_tcp_cansend(psock) >= 0)
{
fds->revents |= (POLLWRNORM & fds->events);
}
/* Check if any requested events are already in effect */
if (fds->revents != 0)
{
/* Yes.. then signal the poll logic */
nxsem_post(fds->sem);
}
errout_with_lock:
net_unlock();
return ret;
}
/****************************************************************************
* Name: tcp_pollteardown
*
* Description:
* Teardown monitoring of events on an TCP/IP socket
*
* Input Parameters:
* psock - The TCP/IP socket of interest
* fds - The structure describing the events to be monitored, OR NULL if
* this is a request to stop monitoring events.
*
* Returned Value:
* 0: Success; Negated errno on failure
*
****************************************************************************/
int tcp_pollteardown(FAR struct socket *psock, FAR struct pollfd *fds)
{
FAR struct tcp_conn_s *conn = psock->s_conn;
FAR struct tcp_poll_s *info;
/* Sanity check */
#ifdef CONFIG_DEBUG_FEATURES
if (!conn || !fds->priv)
{
return -EINVAL;
}
#endif
/* Recover the socket descriptor poll state info from the poll structure */
info = (FAR struct tcp_poll_s *)fds->priv;
DEBUGASSERT(info != NULL && info->fds != NULL && info->cb != NULL);
if (info != NULL)
{
/* Release the callback */
tcp_callback_free(conn, info->cb);
/* Release the poll/select data slot */
info->fds->priv = NULL;
/* Then free the poll info container */
info->psock = NULL;
}
return OK;
}