/**************************************************************************** * net/tcp/tcp_monitor.c * * SPDX-License-Identifier: Apache-2.0 * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * 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 tcp_conn_s *conn, uint16_t flags); static uint16_t tcp_monitor_event(FAR struct net_driver_s *dev, FAR void *pvpriv, uint16_t flags); /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_close_connection * * Description: * Called when a loss-of-connection event has occurred. * * Input Parameters: * conn The TCP connection structure * flags Set of connection events events * * Returned Value: * None * * Assumptions: * The caller holds the network lock. * ****************************************************************************/ static void tcp_close_connection(FAR struct tcp_conn_s *conn, 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" */ conn->sconn.s_flags &= ~_SF_CONNECTED; conn->sconn.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. */ conn->sconn.s_flags &= ~(_SF_CONNECTED | _SF_CLOSED); } } /**************************************************************************** * Name: tcp_monitor_event * * Description: * Some connection related event has occurred * * Input Parameters: * dev The device which as active when the event was detected. * pvpriv An instance of struct tcp_conn_s cast to void* * flags Set of events describing why the callback was invoked * * Returned Value: * None * * Assumptions: * The network is locked. * ****************************************************************************/ static uint16_t tcp_monitor_event(FAR struct net_driver_s *dev, FAR void *pvpriv, uint16_t flags) { FAR struct tcp_conn_s *conn = pvpriv; if (conn != NULL) { ninfo("flags: %04x s_flags: %02x\n", flags, conn->sconn.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(conn, 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 = 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. */ /* Clear the socket error */ _SO_CONN_SETERRNO(conn, OK); /* Indicate that the socket is now connected */ conn->sconn.s_flags |= (_SF_BOUND | _SF_CONNECTED); conn->sconn.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) { /* Perform callbacks to assure that all sockets, including dup'ed copies, * are informed of the loss of connection event. */ net_lock(); /* Free all allocated connection event callback structures */ while (conn->connevents != NULL) { devif_conn_callback_free(conn->dev, conn->connevents, &conn->connevents, &conn->connevents_tail); } 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 devif_callback_s *cb; FAR struct tcp_conn_s *conn; bool nonblock_conn; conn = psock->s_conn; net_lock(); /* Non-blocking connection ? */ nonblock_conn = (conn->tcpstateflags == TCP_SYN_SENT && _SS_ISNONBLOCK(conn->sconn.s_flags)); /* 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.) */ if (!(conn->tcpstateflags == TCP_ESTABLISHED || conn->tcpstateflags == TCP_SYN_RCVD || nonblock_conn)) { /* Invoke the TCP_CLOSE connection event now */ tcp_shutdown_monitor(conn, TCP_CLOSE); /* If the peer close the connection before we call accept, * in order to allow user to read the readahead data, * return OK. */ if (conn->tcpstateflags == TCP_CLOSED || conn->tcpstateflags == TCP_LAST_ACK) { net_unlock(); return OK; } /* 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, &conn->connevents_tail); if (cb != NULL) { cb->event = tcp_monitor_event; cb->priv = (FAR void *)conn; cb->flags = TCP_DISCONN_EVENTS; /* Monitor the connected event */ if (nonblock_conn) { cb->flags |= TCP_CONNECTED; } } net_unlock(); return OK; } /**************************************************************************** * Name: tcp_stop_monitor * * Description: * Stop monitoring TCP connection changes for a sockets associated with * a given TCP connection structure. * * 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_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: * conn - The TCP connection of interest * 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 tcp_conn_s *conn, FAR struct devif_callback_s *cb, uint16_t flags) { DEBUGASSERT(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(conn, flags); /* Then stop the network monitor for all sockets. */ tcp_shutdown_monitor(conn, flags); } #endif /* NET_TCP_HAVE_STACK */