/**************************************************************************** * net/tcp/tcp_netpoll.c * * 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 #include #include #include "devif/devif.h" #include "netdev/netdev.h" #include "socket/socket.h" #include "inet/inet.h" #include "tcp/tcp.h" /**************************************************************************** * 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 * pvpriv An instance of struct tcp_poll_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_poll_eventhandler(FAR struct net_driver_s *dev, FAR void *pvpriv, uint16_t flags) { FAR struct tcp_poll_s *info = pvpriv; int reason; ninfo("flags: %04x\n", flags); DEBUGASSERT(info == NULL || (info->conn != 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; } /* Non-blocking connection */ if ((flags & TCP_CONNECTED) != 0) { eventset |= POLLOUT; } /* Check for a loss of connection events. */ if ((flags & TCP_DISCONN_EVENTS) != 0) { /* TCP_TIMEDOUT: Connection aborted due to too many * retransmissions. */ if ((flags & TCP_TIMEDOUT) != 0) { /* Indicate that the connection timedout?) */ reason = ETIMEDOUT; } else if ((flags & NETDEV_DOWN) != 0) { /* The network device went down. Indicate that the remote host * is unreachable. */ reason = ENETUNREACH; } /* TCP_CLOSE: The remote host has closed the connection * TCP_ABORT: The remote host has aborted the connection */ else { /* Indicate that remote host refused the connection */ reason = ECONNREFUSED; } #ifdef CONFIG_NET_SOCKOPTS info->conn->sconn.s_error = reason; #endif set_errno(reason); /* Mark that the connection has been lost */ tcp_lost_connection(info->conn, info->cb, flags); eventset |= (POLLERR | POLLHUP); } /* A poll is a sign that we are free to send data. */ /* Wake up poll() speculatively on TCP_ACKDATA. * Note: our event handler is usually executed before * psock_send_eventhandler, which might free IOBs/WRBs on TCP_ACKDATA. * Revisit: consider some kind of priority for devif callback to allow * this callback to be inserted after psock_send_eventhandler. */ else if (psock_tcp_cansend(info->conn) >= 0 #if defined(CONFIG_NET_TCP_WRITE_BUFFERS) || (flags & TCP_ACKDATA) != 0 #endif ) { eventset |= POLLOUT; } /* Awaken the caller of poll() if requested event occurred. */ poll_notify(&info->fds, 1, eventset); if (info->fds->revents != 0) { /* Stop further callbacks */ info->cb->flags = 0; info->cb->priv = NULL; info->cb->event = NULL; } } return flags; } /**************************************************************************** * 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; FAR struct tcp_poll_s *info; FAR struct devif_callback_s *cb; pollevent_t eventset = 0; bool nonblock_conn; int ret = OK; /* Some of the following must be atomic */ net_lock(); conn = psock->s_conn; /* Sanity check */ if (!conn || !fds) { ret = -EINVAL; goto errout_with_lock; } /* Non-blocking connection ? */ nonblock_conn = (conn->tcpstateflags == TCP_SYN_SENT && _SS_ISNONBLOCK(conn->sconn.s_flags)); /* Find a container to hold the poll information */ info = conn->pollinfo; while (info->conn != NULL) { if (++info >= &conn->pollinfo[CONFIG_NET_TCP_NPOLLWAITERS]) { ret = -ENOMEM; goto errout_with_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->conn = conn; info->fds = fds; info->cb = cb; /* 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_DISCONN_EVENTS; cb->priv = (FAR void *)info; cb->event = tcp_poll_eventhandler; if ((fds->events & POLLOUT) != 0) { cb->flags |= TCP_POLL #if defined(CONFIG_NET_TCP_WRITE_BUFFERS) | TCP_ACKDATA #endif ; /* Monitor the connected event */ if (nonblock_conn) { cb->flags |= TCP_CONNECTED; } } if ((fds->events & POLLIN) != 0) { cb->flags |= TCP_NEWDATA | TCP_BACKLOG; } /* 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; /* Check for read data or backlogged connection availability now */ if (conn->readahead != NULL || tcp_backlogavailable(conn)) { /* Normal data may be read without blocking. */ eventset |= POLLRDNORM; } /* 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 (!nonblock_conn && !_SS_ISCONNECTED(conn->sconn.s_flags) && !_SS_ISLISTENING(conn->sconn.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. */ eventset |= POLLERR | POLLHUP; } else if (_SS_ISCONNECTED(conn->sconn.s_flags) && psock_tcp_cansend(conn) >= 0) { eventset |= POLLWRNORM; } /* Check if any requested events are already in effect */ poll_notify(&fds, 1, eventset); errout_with_lock: 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; FAR struct tcp_poll_s *info; /* Some of the following must be atomic */ net_lock(); conn = psock->s_conn; /* Sanity check */ if (!conn || !fds->priv) { net_unlock(); return -EINVAL; } /* Recover the socket descriptor poll state info from the poll structure */ info = (FAR struct tcp_poll_s *)fds->priv; DEBUGASSERT(info->fds != NULL && info->cb != NULL); if (info != NULL) { /* Release the callback */ tcp_callback_free(conn, info->cb); /* Release the poll/select data slot */ info->fds->priv = NULL; /* Then free the poll info container */ info->conn = NULL; } net_unlock(); return OK; }