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nuttx/net/tcp/tcp_netpoll.c

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/****************************************************************************
* 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 <poll.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/wqueue.h>
#include <nuttx/mm/iob.h>
#include <nuttx/net/net.h>
#include "devif/devif.h"
#include "netdev/netdev.h"
#include "socket/socket.h"
#include "inet/inet.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 */
#if defined(CONFIG_NET_TCP_WRITE_BUFFERS) && defined(CONFIG_IOB_NOTIFIER)
int16_t key; /* Needed to cancel pending notification */
#endif
};
/****************************************************************************
* 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;
}
/* A poll is a sign that we are free to send data.
* REVISIT: This is bogus: If CONFIG_TCP_WRITE_BUFFERS=y then
* we never have to wait to send; otherwise, we always have to
* wait to send. Receiving a poll is irrelevant.
*/
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 */
tcp_lost_connection(info->psock, info->cb, flags);
eventset |= (POLLERR | POLLHUP);
}
/* 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;
}
/****************************************************************************
* Name: tcp_iob_work
*
* Description:
* Work thread callback function execute when an IOB because available.
*
* Input Parameters:
* psock - Socket state structure
*
* Returned Value:
* None
*
****************************************************************************/
#if defined(CONFIG_NET_TCP_WRITE_BUFFERS) && defined(CONFIG_IOB_NOTIFIER)
static inline void tcp_iob_work(FAR void *arg)
{
FAR struct work_notifier_entry_s *entry;
FAR struct work_notifier_s *ninfo;
FAR struct tcp_poll_s *pinfo;
FAR struct socket *psock;
FAR struct pollfd *fds;
entry = (FAR struct work_notifier_entry_s *)arg;
DEBUGASSERT(entry != NULL);
ninfo = &entry->info;
DEBUGASSERT(ninfo->arg != NULL);
pinfo = (FAR struct tcp_poll_s *)ninfo->arg;
DEBUGASSERT(pinfo->psock != NULL && pinfo->fds != NULL);
psock = pinfo->psock;
fds = pinfo->fds;
/* Verify that we still have a connection */
if (!_SS_ISCONNECTED(psock->s_flags) && !_SS_ISLISTENING(psock->s_flags))
{
/* Don't report more than once. Might happen in a race condition */
if ((fds->revents & (POLLERR | POLLHUP)) == 0)
{
/* 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);
nxsem_post(fds->sem);
}
}
/* Handle a race condition. Check if we have already posted the POLLOUT
* event. If so, don't do it again and don't setup notification again.
*/
else if ((fds->events && POLLWRNORM) == 0 ||
(fds->revents && POLLWRNORM) != 0)
{
/* Check if we are now able to send */
if (psock_tcp_cansend(psock) >= 0)
{
/* Yes.. then signal the poll logic */
fds->revents |= POLLWRNORM;
nxsem_post(fds->sem);
}
else
{
/* No.. ask for the IOB free notification again */
pinfo->key = iob_notifier_setup(LPWORK, tcp_iob_work, pinfo);
}
}
/* Protocol for the use of the IOB notifier is that we free the argument
* after the notification has been processed.
*/
kmm_free(arg);
}
#endif
/****************************************************************************
* Name: tcp_poll_txnotify
*
* Description:
* Notify the appropriate device driver that we are have data ready to
* be sent (TCP)
*
* Input Parameters:
* psock - Socket state structure
*
* Returned Value:
* None
*
****************************************************************************/
#if !defined(CONFIG_NET_TCP_WRITE_BUFFERS) || !defined(CONFIG_IOB_NOTIFIER)
static inline void tcp_poll_txnotify(FAR struct socket *psock)
{
FAR struct tcp_conn_s *conn = psock->s_conn;
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
/* If both IPv4 and IPv6 support are enabled, then we will need to select
* the device driver using the appropriate IP domain.
*/
if (psock->s_domain == PF_INET)
#endif
{
/* Notify the device driver that send data is available */
netdev_ipv4_txnotify(conn->u.ipv4.laddr, conn->u.ipv4.raddr);
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else /* if (psock->s_domain == PF_INET6) */
#endif /* CONFIG_NET_IPv4 */
{
/* Notify the device driver that send data is available */
DEBUGASSERT(psock->s_domain == PF_INET6);
netdev_ipv6_txnotify(conn->u.ipv6.laddr, conn->u.ipv6.raddr);
}
#endif /* CONFIG_NET_IPv6 */
}
#endif
/****************************************************************************
* 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;
/* 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 */
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;
#if defined(CONFIG_NET_TCP_WRITE_BUFFERS) && defined(CONFIG_IOB_NOTIFIER)
info->key = 0;
#endif
/* 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_eventhandler;
/* 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 */
nxsem_post(fds->sem);
}
#if defined(CONFIG_NET_TCP_WRITE_BUFFERS) && defined(CONFIG_IOB_NOTIFIER)
/* If (1) revents == 0, (2) write buffering is enabled, and (3) the
* POLLOUT event is needed, then setup to receive a notification an IOB
* is freed.
*/
else if ((fds->events & POLLOUT) != 0)
{
/* Ask for the IOB free notification */
info->key = iob_notifier_setup(LPWORK, tcp_iob_work, info);
}
#else
/* If (1) the socket is in a bound state, (2) revents == 0, (3) write
* buffering is not enabled (determined by a configuration setting), and
* (4) the POLLOUT event is needed then request an immediate Tx poll from
* the device associated with the binding.
*/
else if (_SS_ISBOUND(psock->s_flags) && (fds->events & POLLOUT) != 0)
{
/* Note that the notification will fail if the socket is bound to
* INADDR_ANY or the IPv6 unspecified address! In that case the
* notification will fail.
*/
tcp_poll_txnotify(psock);
}
#endif
net_unlock();
return OK;
errout_with_lock:
kmm_free(info);
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)
{
#if defined(CONFIG_NET_TCP_WRITE_BUFFERS) && defined(CONFIG_IOB_NOTIFIER)
/* Cancel any pending IOB free notification */
if (info->key > 0)
{
/* Ask for the IOB free notification */
iob_notifier_teardown(info->key);
}
#endif
/* Release the callback */
net_lock();
tcp_callback_free(conn, info->cb);
net_unlock();
/* 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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