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incubator-nuttx/net/tcp/tcp_close.c

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/****************************************************************************
* net/tcp/tcp_close.c
*
* Copyright (C) 2020 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>
#ifdef CONFIG_NET_TCP
#include <errno.h>
#include <debug.h>
#include <assert.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/tcp.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "tcp/tcp.h"
#include "socket/socket.h"
/****************************************************************************
* Private Types
****************************************************************************/
struct tcp_close_s
{
FAR struct devif_callback_s *cl_cb; /* Reference to TCP callback instance */
FAR struct socket *cl_psock; /* Reference to the TCP socket */
sem_t cl_sem; /* Signals disconnect completion */
int cl_result; /* The result of the close */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_close_eventhandler
****************************************************************************/
static uint16_t tcp_close_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvconn, FAR void *pvpriv,
uint16_t flags)
{
FAR struct tcp_close_s *pstate = (FAR struct tcp_close_s *)pvpriv;
FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn;
DEBUGASSERT(pstate != NULL && conn != NULL);
ninfo("conn: %p flags: %04x\n", conn, flags);
/* TCP_DISCONN_EVENTS:
* TCP_CLOSE: The remote host has closed the connection
* TCP_ABORT: The remote host has aborted the connection
* TCP_TIMEDOUT: The remote did not respond, the connection timed out
* NETDEV_DOWN: The network device went down
*/
if ((flags & TCP_DISCONN_EVENTS) != 0)
{
/* The disconnection is complete. Wake up the waiting thread with an
* appropriate result. Success is returned in these cases:
*
* * TCP_CLOSE indicates normal successful closure. The TCP_CLOSE
* event is sent when the remote ACKs the outgoing FIN in the
* FIN_WAIT_1 state. That is the appropriate time for the
* application to close the socket.
*
* NOTE: The underlying connection, however, will persist, waiting
* for the FIN to be returned by the remote in the TIME_WAIT state.
*
* * TCP_ABORT is less likely but still means that the socket was
* closed, albeit abnormally due to a RST from the remote.
*
* * TCP_TIMEDOUT would be reported in this context if there is no
* ACK response to the FIN in the FIN_WAIT_2 state. The socket will
* again be closed abnormally.
*
* This is the only true error case.
*
* * NETDEV_DOWN would indicate that the network went down before the
* close completed. A non-standard ENODEV error will be returned
* in this case. The socket will be left in a limbo state if the
* network is taken down but should recover later when the
* NETWORK_DOWN event is processed further.
*/
if ((flags & NETDEV_DOWN) != 0)
{
pstate->cl_result = -ENODEV;
}
else
{
pstate->cl_result = OK;
}
goto end_wait;
}
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
/* Check if all outstanding bytes have been ACKed */
else if (conn->tx_unacked != 0 || !sq_empty(&conn->write_q))
{
/* No... we are still waiting for ACKs. Drop any received data, but
* do not yet report TCP_CLOSE in the response.
*/
dev->d_len = 0;
flags &= ~TCP_NEWDATA;
}
#endif /* CONFIG_NET_TCP_WRITE_BUFFERS */
else
{
/* Drop data received in this state and make sure that TCP_CLOSE
* is set in the response
*/
dev->d_len = 0;
flags = (flags & ~TCP_NEWDATA) | TCP_CLOSE;
}
UNUSED(conn); /* May not be used */
return flags;
end_wait:
pstate->cl_cb->flags = 0;
pstate->cl_cb->priv = NULL;
pstate->cl_cb->event = NULL;
nxsem_post(&pstate->cl_sem);
ninfo("Resuming\n");
return flags;
}
/****************************************************************************
* Name: tcp_close_txnotify
*
* Description:
* Notify the appropriate device driver that we are have data ready to
* be send (TCP)
*
* Input Parameters:
* psock - Socket state structure
* conn - The TCP connection structure
*
* Returned Value:
* None
*
****************************************************************************/
static inline void tcp_close_txnotify(FAR struct socket *psock,
FAR struct tcp_conn_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 */
}
/****************************************************************************
* Name: tcp_close_disconnect
*
* Description:
* Break any current TCP connection
*
* Input Parameters:
* conn - TCP connection structure
*
* Returned Value:
* None
*
* Assumptions:
* Called from normal user-level logic
*
****************************************************************************/
static inline int tcp_close_disconnect(FAR struct socket *psock)
{
struct tcp_close_s state;
FAR struct tcp_conn_s *conn;
int ret = OK;
/* Interrupts are disabled here to avoid race conditions */
net_lock();
conn = (FAR struct tcp_conn_s *)psock->s_conn;
DEBUGASSERT(conn != NULL);
#ifdef CONFIG_NET_SOLINGER
/* SO_LINGER
* Lingers on a close() if data is present. This option controls the
* action taken when unsent messages queue on a socket and close() is
* performed. If SO_LINGER is set, the system shall block the calling
* thread during close() until it can transmit the data or until the
* time expires. If SO_LINGER is not specified, and close() is issued,
* the system handles the call in a way that allows the calling thread
* to continue as quickly as possible. This option takes a linger
* structure, as defined in the <sys/socket.h> header, to specify the
* state of the option and linger interval.
*/
if (_SO_GETOPT(psock->s_options, SO_LINGER))
{
/* Wait until for the buffered TX data to be sent. */
ret = tcp_txdrain(psock, _SO_TIMEOUT(psock->s_linger));
if (ret < 0)
{
/* tcp_txdrain may fail, but that won't stop us from closing
* the socket.
*/
nerr("ERROR: tcp_txdrain() failed: %d\n", ret);
}
}
#endif
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
/* If we have a semi-permanent write buffer callback in place, then
* is needs to be be nullified.
*
* Commit f1ef2c6cdeb032eaa1833cc534a63b50c5058270:
* "When a socket is closed, it should make sure that any pending write
* data is sent before the FIN is sent. It already would wait for all
* sent data to be acked, however it would discard any pending write
* data that had not been sent at least once.
*
* "This change adds a check for pending write data in addition to unacked
* data. However, to be able to actually send any new data, the send
* callback must be left. The callback should be freed later when the
* socket is actually destroyed."
*
* REVISIT: Where and how exactly is s_sndcb ever freed? Is there a
* memory leak here?
*/
psock->s_sndcb = NULL;
#endif
/* Check for the case where the host beat us and disconnected first */
if (conn->tcpstateflags == TCP_ESTABLISHED &&
(state.cl_cb = tcp_callback_alloc(conn)) != NULL)
{
/* Set up to receive TCP data event callbacks */
state.cl_cb->flags = (TCP_NEWDATA | TCP_POLL | TCP_DISCONN_EVENTS);
state.cl_cb->event = tcp_close_eventhandler;
/* A non-NULL value of the priv field means that lingering is
* enabled.
*/
state.cl_cb->priv = (FAR void *)&state;
/* Set up for the lingering wait */
state.cl_psock = psock;
state.cl_result = -EBUSY;
/* This semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
nxsem_init(&state.cl_sem, 0, 0);
nxsem_setprotocol(&state.cl_sem, SEM_PRIO_NONE);
/* Notify the device driver of the availability of TX data */
tcp_close_txnotify(psock, conn);
/* Wait for the disconnect event */
net_lockedwait(&state.cl_sem);
/* We are now disconnected */
nxsem_destroy(&state.cl_sem);
tcp_callback_free(conn, state.cl_cb);
/* Free the connection
* No more references on the connection
*/
conn->crefs = 0;
/* Get the result of the close */
ret = state.cl_result;
}
/* Free network resources */
tcp_free(conn);
net_unlock();
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_close
*
* Description:
* Break any current TCP connection
*
* Input Parameters:
* psock - An instance of the internal socket structure.
*
* Assumptions:
* Called from normal user-level logic
*
****************************************************************************/
int tcp_close(FAR struct socket *psock)
{
FAR struct tcp_conn_s *conn = psock->s_conn;
int ret;
/* Perform the disconnection now */
tcp_unlisten(conn); /* No longer accepting connections */
conn->crefs = 0; /* Discard our reference to the connection */
/* Break any current connections and close the socket */
ret = tcp_close_disconnect(psock);
if (ret < 0)
{
/* This would normally occur only if there is a timeout
* from a lingering close.
*/
nerr("ERROR: tcp_close_disconnect failed: %d\n", ret);
return ret;
}
/* Stop the network monitor for all sockets */
tcp_stop_monitor(conn, TCP_CLOSE);
return OK;
}
#endif /* CONFIG_NET_TCP */
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