358 lines
9.7 KiB
C
358 lines
9.7 KiB
C
/****************************************************************************
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* net/tcp/tcp_netpoll.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <assert.h>
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#include <poll.h>
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#include <debug.h>
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#include <nuttx/net/net.h>
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#include <nuttx/semaphore.h>
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#include "devif/devif.h"
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#include "netdev/netdev.h"
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#include "socket/socket.h"
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#include "inet/inet.h"
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#include "tcp/tcp.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tcp_poll_eventhandler
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*
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* Description:
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* This function is called to perform the actual TCP receive operation via
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* the device interface layer.
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*
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* Input Parameters:
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* dev The structure of the network driver that caused the event
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* conn The connection structure associated with the socket
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* flags Set of events describing why the callback was invoked
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*
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* Returned Value:
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* None
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*
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* Assumptions:
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* The network is locked
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*
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****************************************************************************/
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static uint16_t tcp_poll_eventhandler(FAR struct net_driver_s *dev,
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FAR void *conn,
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FAR void *pvpriv, uint16_t flags)
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{
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FAR struct tcp_poll_s *info = (FAR struct tcp_poll_s *)pvpriv;
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ninfo("flags: %04x\n", flags);
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DEBUGASSERT(info == NULL || (info->psock != NULL && info->fds != NULL));
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/* 'priv' might be null in some race conditions (?) */
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if (info != NULL)
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{
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pollevent_t eventset = 0;
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/* Check for data or connection availability events. */
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if ((flags & (TCP_NEWDATA | TCP_BACKLOG)) != 0)
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{
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eventset |= POLLIN & info->fds->events;
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}
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/* Check for a loss of connection events. */
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if ((flags & TCP_DISCONN_EVENTS) != 0)
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{
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/* Mark that the connection has been lost */
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tcp_lost_connection(info->psock, info->cb, flags);
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eventset |= (POLLERR | POLLHUP);
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}
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/* A poll is a sign that we are free to send data. */
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/* Wake up poll() speculatively on TCP_ACKDATA.
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* Note: our event handler is usually executed before
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* psock_send_eventhandler, which might free IOBs/WRBs on TCP_ACKDATA.
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* Revisit: consider some kind of priority for devif callback to allow
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* this callback to be inserted after psock_send_eventhandler.
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*/
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else if (psock_tcp_cansend(info->psock) >= 0
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#if defined(CONFIG_NET_TCP_WRITE_BUFFERS)
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|| (flags & TCP_ACKDATA) != 0
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#endif
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)
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{
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eventset |= (POLLOUT & info->fds->events);
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}
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/* Awaken the caller of poll() if requested event occurred. */
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if (eventset != 0)
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{
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/* Stop further callbacks */
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info->cb->flags = 0;
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info->cb->priv = NULL;
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info->cb->event = NULL;
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info->fds->revents |= eventset;
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nxsem_post(info->fds->sem);
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}
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}
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return flags;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tcp_pollsetup
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*
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* Description:
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* Setup to monitor events on one TCP/IP socket
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*
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* Input Parameters:
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* psock - The TCP/IP socket of interest
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* fds - The structure describing the events to be monitored, OR NULL if
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* this is a request to stop monitoring events.
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*
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* Returned Value:
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* 0: Success; Negated errno on failure
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*
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****************************************************************************/
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int tcp_pollsetup(FAR struct socket *psock, FAR struct pollfd *fds)
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{
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FAR struct tcp_conn_s *conn = psock->s_conn;
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FAR struct tcp_poll_s *info;
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FAR struct devif_callback_s *cb;
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int ret = OK;
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/* Sanity check */
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#ifdef CONFIG_DEBUG_FEATURES
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if (!conn || !fds)
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{
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return -EINVAL;
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}
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#endif
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/* Some of the following must be atomic */
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net_lock();
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/* Find a container to hold the poll information */
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info = conn->pollinfo;
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while (info->psock != NULL)
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{
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if (++info >= &conn->pollinfo[CONFIG_NET_TCP_NPOLLWAITERS])
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{
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ret = -ENOMEM;
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goto errout_with_lock;
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}
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}
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/* Allocate a TCP/IP callback structure */
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cb = tcp_callback_alloc(conn);
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if (!cb)
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{
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ret = -EBUSY;
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goto errout_with_lock;
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}
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/* Initialize the poll info container */
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info->psock = psock;
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info->fds = fds;
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info->cb = cb;
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/* Initialize the callback structure. Save the reference to the info
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* structure as callback private data so that it will be available during
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* callback processing.
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*/
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cb->flags = TCP_DISCONN_EVENTS;
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cb->priv = (FAR void *)info;
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cb->event = tcp_poll_eventhandler;
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if ((fds->events & POLLOUT) != 0)
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{
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cb->flags |= TCP_POLL
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#if defined(CONFIG_NET_TCP_WRITE_BUFFERS)
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| TCP_ACKDATA
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#endif
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;
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}
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if ((fds->events & POLLIN) != 0)
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{
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cb->flags |= TCP_NEWDATA | TCP_BACKLOG;
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}
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/* Save the reference in the poll info structure as fds private as well
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* for use during poll teardown as well.
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*/
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fds->priv = (FAR void *)info;
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/* Check for read data or backlogged connection availability now */
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if (!IOB_QEMPTY(&conn->readahead) || tcp_backlogavailable(conn))
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{
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/* Normal data may be read without blocking. */
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fds->revents |= (POLLRDNORM & fds->events);
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}
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/* Check for a loss of connection events. We need to be careful here.
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* There are four possibilities:
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*
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* 1) The socket is connected and we are waiting for data availability
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* events.
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*
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* __SS_ISCONNECTED(f) == true
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* __SS_ISLISTENING(f) == false
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* __SS_ISCLOSED(f) == false
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*
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* Action: Wait for data availability events
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*
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* 2) This is a listener socket that was never connected and we are
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* waiting for connection events.
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*
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* __SS_ISCONNECTED(f) == false
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* __SS_ISLISTENING(f) == true
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* __SS_ISCLOSED(f) == false
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*
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* Action: Wait for connection events
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*
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* 3) This socket was previously connected, but the peer has gracefully
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* closed the connection.
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*
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* __SS_ISCONNECTED(f) == false
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* __SS_ISLISTENING(f) == false
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* __SS_ISCLOSED(f) == true
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*
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* Action: Return with POLLHUP|POLLERR events
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*
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* 4) This socket was previously connected, but we lost the connection
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* due to some exceptional event.
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*
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* __SS_ISCONNECTED(f) == false
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* __SS_ISLISTENING(f) == false
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* __SS_ISCLOSED(f) == false
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*
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* Action: Return with POLLHUP|POLLERR events
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*/
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if (!_SS_ISCONNECTED(psock->s_flags) && !_SS_ISLISTENING(psock->s_flags))
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{
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/* We were previously connected but lost the connection either due
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* to a graceful shutdown by the remote peer or because of some
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* exceptional event.
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*/
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fds->revents |= (POLLERR | POLLHUP);
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}
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else if (_SS_ISCONNECTED(psock->s_flags) && psock_tcp_cansend(psock) >= 0)
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{
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fds->revents |= (POLLWRNORM & fds->events);
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}
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/* Check if any requested events are already in effect */
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if (fds->revents != 0)
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{
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/* Yes.. then signal the poll logic */
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nxsem_post(fds->sem);
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}
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errout_with_lock:
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net_unlock();
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return ret;
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}
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/****************************************************************************
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* Name: tcp_pollteardown
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*
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* Description:
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* Teardown monitoring of events on an TCP/IP socket
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*
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* Input Parameters:
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* psock - The TCP/IP socket of interest
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* fds - The structure describing the events to be monitored, OR NULL if
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* this is a request to stop monitoring events.
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*
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* Returned Value:
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* 0: Success; Negated errno on failure
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*
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****************************************************************************/
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int tcp_pollteardown(FAR struct socket *psock, FAR struct pollfd *fds)
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{
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FAR struct tcp_conn_s *conn = psock->s_conn;
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FAR struct tcp_poll_s *info;
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/* Sanity check */
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#ifdef CONFIG_DEBUG_FEATURES
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if (!conn || !fds->priv)
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{
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return -EINVAL;
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}
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#endif
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/* Recover the socket descriptor poll state info from the poll structure */
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info = (FAR struct tcp_poll_s *)fds->priv;
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DEBUGASSERT(info != NULL && info->fds != NULL && info->cb != NULL);
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if (info != NULL)
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{
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/* Release the callback */
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tcp_callback_free(conn, info->cb);
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/* Release the poll/select data slot */
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info->fds->priv = NULL;
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/* Then free the poll info container */
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info->psock = NULL;
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}
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return OK;
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}
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