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incubator-nuttx/net/tcp/tcp_netpoll.c

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/****************************************************************************
* net/tcp/tcp_netpoll.c
*
* Copyright (C) 2008-2009, 2011-2016 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 <poll.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/net/net.h>
#include <devif/devif.h>
#include <socket/socket.h>
#include "tcp/tcp.h"
#ifdef HAVE_TCP_POLL
/****************************************************************************
* Private Types
****************************************************************************/
/* This is an allocated container that holds the poll-related information */
struct tcp_poll_s
{
FAR struct socket *psock; /* Needed to handle loss of connection */
struct pollfd *fds; /* Needed to handle poll events */
FAR struct devif_callback_s *cb; /* Needed to teardown the poll */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Function: tcp_poll_interrupt
*
* Description:
* This function is called from the interrupt level to perform the actual
* TCP receive operation via by the device interface layer.
*
* Parameters:
* dev The structure of the network driver that caused the interrupt
* conn The connection structure associated with the socket
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* Running at the interrupt level
*
****************************************************************************/
static uint16_t tcp_poll_interrupt(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 || (info->psock && info->fds));
/* 'priv' might be null in some race conditions (?) */
if (info)
{
pollevent_t eventset = 0;
/* Check for data or connection availability events. */
if ((flags & (TCP_NEWDATA | TCP_BACKLOG)) != 0)
{
eventset |= POLLIN & info->fds->events;
}
/* A poll is a sign that we are free to send data. */
if ((flags & TCP_POLL) != 0)
{
eventset |= (POLLOUT & info->fds->events);
}
/* Check for a loss of connection events. */
if ((flags & TCP_DISCONN_EVENTS) != 0)
{
/* Mark that the connection has been lost */
net_lostconnection(info->psock, flags);
eventset |= (POLLERR | POLLHUP);
}
/* Awaken the caller of poll() if requested event occurred. */
if (eventset)
{
info->fds->revents |= eventset;
sem_post(info->fds->sem);
}
}
return flags;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: 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;
net_lock_t flags;
int ret;
/* Sanity check */
#ifdef CONFIG_DEBUG_FEATURES
if (!conn || !fds)
{
return -EINVAL;
}
#endif
/* Allocate a container to hold the poll information */
info = (FAR struct tcp_poll_s *)kmm_malloc(sizeof(struct tcp_poll_s));
if (!info)
{
return -ENOMEM;
}
/* Some of the following must be atomic */
flags = net_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_NEWDATA | TCP_BACKLOG | TCP_POLL | TCP_DISCONN_EVENTS);
cb->priv = (FAR void *)info;
cb->event = tcp_poll_interrupt;
/* 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;
#ifdef CONFIG_NET_TCPBACKLOG
/* Check for read data or backlogged connection availability now */
if (!IOB_QEMPTY(&conn->readahead) || tcp_backlogavailable(conn))
#else
/* Check for read data availability now */
if (!IOB_QEMPTY(&conn->readahead))
#endif
{
/* 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 */
sem_post(fds->sem);
}
net_unlock(flags);
return OK;
errout_with_lock:
kmm_free(info);
net_unlock(flags);
return ret;
}
/****************************************************************************
* Function: 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;
net_lock_t flags;
/* 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 && info->fds && info->cb);
if (info)
{
/* Release the callback */
flags = net_lock();
tcp_callback_free(conn, info->cb);
net_unlock(flags);
/* Release the poll/select data slot */
info->fds->priv = NULL;
/* Then free the poll info container */
kmm_free(info);
}
return OK;
}
#endif /* HAVE_TCP_POLL */
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