/**************************************************************************** * net/tcp/tcp_monitor.c * * Copyright (C) 2007-2013, 2017-2018 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include "devif/devif.h" #include "socket/socket.h" #include "tcp/tcp.h" #ifdef NET_TCP_HAVE_STACK /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static void tcp_close_connection(FAR struct socket *psock, uint16_t flags); static uint16_t tcp_disconnect_event(FAR struct net_driver_s *dev, FAR void *pvconn, FAR void *pvpriv, uint16_t flags); /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_close_connection * * Description: * Called when a loss-of-connection event has occurred. * * Input Parameters: * psock The TCP socket structure associated. * flags Set of connection events events * * Returned Value: * None * * Assumptions: * The caller holds the network lock. * ****************************************************************************/ static void tcp_close_connection(FAR struct socket *psock, uint16_t flags) { /* These loss-of-connection events may be reported: * * TCP_CLOSE: The remote host has closed the connection * TCP_ABORT: The remote host has aborted the connection * TCP_TIMEDOUT: Connection aborted due to too many retransmissions. * NETDEV_DOWN: The network device went down * * And we need to set these two socket status bits appropriately: * * _SF_CONNECTED==1 && _SF_CLOSED==0 - the socket is connected * _SF_CONNECTED==0 && _SF_CLOSED==1 - the socket was gracefully disconnected * _SF_CONNECTED==0 && _SF_CLOSED==0 - the socket was rudely disconnected */ if ((flags & TCP_CLOSE) != 0) { /* The peer gracefully closed the connection. Marking the * connection as disconnected will suppress some subsequent * ENOTCONN errors from receive. A graceful disconnection is * not handle as an error but as an "end-of-file" */ psock->s_flags &= ~_SF_CONNECTED; psock->s_flags |= _SF_CLOSED; } else if ((flags & (TCP_ABORT | TCP_TIMEDOUT | NETDEV_DOWN)) != 0) { /* The loss of connection was less than graceful. This will (eventually) * be reported as an ENOTCONN error. */ psock->s_flags &= ~(_SF_CONNECTED | _SF_CLOSED); } } /**************************************************************************** * Name: tcp_disconnect_event * * Description: * Some connection related event has occurred * * Input Parameters: * dev The device which as active when the event was detected. * 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_disconnect_event(FAR struct net_driver_s *dev, FAR void *pvconn, FAR void *pvpriv, uint16_t flags) { FAR struct socket *psock = (FAR struct socket *)pvpriv; if (psock != NULL) { ninfo("flags: %04x s_flags: %02x\n", flags, psock->s_flags); /* TCP_DISCONN_EVENTS: TCP_CLOSE, TCP_ABORT, TCP_TIMEDOUT, or * NETDEV_DOWN. All loss-of-connection events. */ if ((flags & TCP_DISCONN_EVENTS) != 0) { tcp_close_connection(psock, flags); } /* TCP_CONNECTED: The socket is successfully connected */ else if ((flags & TCP_CONNECTED) != 0) { #if 0 /* REVISIT: Assertion fires. Why? */ FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)psock->s_conn; /* Make sure that this is the device bound to the connection */ DEBUGASSERT(conn->dev == NULL || conn->dev == dev); conn->dev = dev; #endif /* If there is no local address assigned to the socket (perhaps * because it was INADDR_ANY), then assign it the address of the * connecting device. * * TODO: Implement this. */ /* Indicate that the socket is now connected */ psock->s_flags |= _SF_CONNECTED; psock->s_flags &= ~_SF_CLOSED; } } return flags; } /**************************************************************************** * Name: tcp_shutdown_monitor * * Description: * Stop monitoring TCP connection changes for a given socket. * * Input Parameters: * conn - The TCP connection of interest * flags - Indicates the type of shutdown. TCP_CLOSE or TCP_ABORT * * Returned Value: * None * * Assumptions: * The caller holds the network lock (if not, it will be locked momentarily * by this function). * ****************************************************************************/ static void tcp_shutdown_monitor(FAR struct tcp_conn_s *conn, uint16_t flags) { DEBUGASSERT(conn); /* Perform callbacks to assure that all sockets, including dup'ed copies, * are informed of the loss of connection event. */ net_lock(); (void)tcp_callback(conn->dev, conn, flags); /* Free all allocated connection event callback structures */ while (conn->connevents != NULL) { devif_conn_callback_free(conn->dev, conn->connevents, &conn->connevents); } net_unlock(); } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_start_monitor * * Description: * Set up to receive TCP connection state changes for a given socket * * Input Parameters: * psock - The socket of interest * * Returned Value: * On success, tcp_start_monitor returns OK; On any failure, * tcp_start_monitor will return a negated errno value. The only failure * that can occur is if the socket has already been closed and, in this * case, -ENOTCONN is returned. * * Assumptions: * The caller holds the network lock (if not, it will be locked momentarily * by this function). * ****************************************************************************/ int tcp_start_monitor(FAR struct socket *psock) { FAR struct tcp_conn_s *conn; FAR struct devif_callback_s *cb; DEBUGASSERT(psock != NULL && psock->s_conn != NULL); conn = (FAR struct tcp_conn_s *)psock->s_conn; /* Check if the connection has already been closed before any callbacks * have been registered. (Maybe the connection is lost before accept has * registered the monitoring callback.) */ net_lock(); if (!(conn->tcpstateflags == TCP_ESTABLISHED || conn->tcpstateflags == TCP_SYN_RCVD)) { /* Invoke the TCP_CLOSE connection event now */ tcp_shutdown_monitor(conn, TCP_CLOSE); /* And return -ENOTCONN to indicate the monitor was not started * because the socket was already disconnected. */ net_unlock(); return -ENOTCONN; } /* Allocate a callback structure that we will use to get callbacks if * the network goes down. */ cb = devif_callback_alloc(conn->dev, &conn->connevents); if (cb != NULL) { cb->event = tcp_disconnect_event; cb->priv = (FAR void *)psock; cb->flags = TCP_DISCONN_EVENTS; } net_unlock(); return OK; } /**************************************************************************** * Name: tcp_stop_monitor * * Description: * Stop monitoring TCP connection changes for a sockets associated with * a given TCP connection stucture. * * Input Parameters: * conn - The TCP connection of interest * flags Set of disconnection events * * Returned Value: * None * * Assumptions: * The caller holds the network lock (if not, it will be locked momentarily * by this function). * ****************************************************************************/ void tcp_stop_monitor(FAR struct tcp_conn_s *conn, uint16_t flags) { DEBUGASSERT(conn != NULL); /* Stop the network monitor */ tcp_shutdown_monitor(conn, flags); } /**************************************************************************** * Name: tcp_close_monitor * * Description: * One socket in a group of dup'ed sockets has been closed. We need to * selectively terminate just those things that are waiting of events * from this specific socket. And also recover any resources that are * committed to monitoring this socket. * * Input Parameters: * psock - The TCP socket structure that is closed * * Returned Value: * None * * Assumptions: * The caller holds the network lock (if not, it will be locked momentarily * by this function). * ****************************************************************************/ void tcp_close_monitor(FAR struct socket *psock) { FAR struct tcp_conn_s *conn; FAR struct devif_callback_s *cb; DEBUGASSERT(psock != NULL && psock->s_conn != NULL); conn = (FAR struct tcp_conn_s *)psock->s_conn; /* Find and free the the connection event callback */ net_lock(); for (cb = conn->connevents; cb != NULL && cb->priv != (FAR void *)psock; cb = cb->nxtconn) { } if (cb != NULL) { devif_conn_callback_free(conn->dev, cb, &conn->connevents); } /* Make sure that this socket is explicitly marked as closed */ tcp_close_connection(psock, TCP_CLOSE); /* Now notify any sockets waiting for events from this particular sockets. * Other dup'ed sockets sharing the same connection must not be effected. */ /* REVISIT: The following logic won't work: There is no way to compare * psocks to check for a match. This missing logic could only be an issue * if the same socket were being used on one thread, but then closed on * another. Some redesign would be required to find only those event * handlers that are waiting specifically for this socket (vs. a dup of * this socket) */ #if 0 for (cb = conn->list; cb != NULL; cb = cb->nxtconn) { if (cb->event != NULL && (cb->flags & TCP_CLOSE) != 0) { (void)cb->event(conn->dev, conn, cb->priv, TCP_CLOSE); } } #endif net_unlock(); } /**************************************************************************** * Name: tcp_lost_connection * * Description: * Called when a loss-of-connection event has been detected by network * event handling logic. Perform operations like tcp_stop_monitor but (1) * explicitly mark this socket and (2) disable further callbacks the to the * event handler. * * Input Parameters: * psock - The TCP socket structure whose connection was lost. * cb - devif callback structure * flags - Set of connection events events * * Returned Value: * None * * Assumptions: * The caller holds the network lock (if not, it will be locked momentarily * by this function). * ****************************************************************************/ void tcp_lost_connection(FAR struct socket *psock, FAR struct devif_callback_s *cb, uint16_t flags) { DEBUGASSERT(psock != NULL && psock->s_conn != NULL); /* Nullify the callback structure so that recursive callbacks are not * received by the event handler due to disconnection processing. * * NOTE: In a configuration with CONFIG_NET_TCP_WRITE_BUFFERS=y, * the "semi-permanent" callback structure may have already been * nullified. */ if (cb != NULL) { cb->flags = 0; cb->priv = NULL; cb->event = NULL; } /* Make sure that this socket is explicitly marked. It may not get a * callback due to the above nullification. */ tcp_close_connection(psock, flags); /* Then stop the network monitor for all sockets. */ tcp_shutdown_monitor((FAR struct tcp_conn_s *)psock->s_conn, flags); } #endif /* NET_TCP_HAVE_STACK */