/****************************************************************************
 * net/usrsock/usrsock_listen.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 <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_USRSOCK)

#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/net/net.h>
#include <nuttx/net/usrsock.h>

#include "usrsock/usrsock.h"

/****************************************************************************
 * Private Functions
 ****************************************************************************/

static uint16_t listen_event(FAR struct net_driver_s *dev,
                             FAR void *pvpriv, uint16_t flags)
{
  FAR struct usrsock_reqstate_s *pstate = pvpriv;
  FAR struct usrsock_conn_s *conn = pstate->conn;

  if (flags & USRSOCK_EVENT_ABORT)
    {
      ninfo("socket aborted.\n");

      pstate->result = -ECONNABORTED;

      /* Stop further callbacks */

      pstate->cb->flags = 0;
      pstate->cb->priv  = NULL;
      pstate->cb->event = NULL;

      /* Wake up the waiting thread */

      nxsem_post(&pstate->recvsem);
    }
  else if (flags & USRSOCK_EVENT_REQ_COMPLETE)
    {
      ninfo("request completed.\n");

      pstate->result = conn->resp.result;

      /* Stop further callbacks */

      pstate->cb->flags = 0;
      pstate->cb->priv  = NULL;
      pstate->cb->event = NULL;

      /* Wake up the waiting thread */

      nxsem_post(&pstate->recvsem);
    }

  return flags;
}

/****************************************************************************
 * Name: do_listen_request
 ****************************************************************************/

static int do_listen_request(FAR struct usrsock_conn_s *conn, int backlog)
{
  struct usrsock_request_listen_s req =
  {
  };

  struct iovec bufs[1];

  if (backlog > UINT16_MAX)
    {
      backlog = UINT16_MAX;
    }

  /* Prepare request for daemon to read. */

  req.head.reqid = USRSOCK_REQUEST_LISTEN;
  req.usockid = conn->usockid;
  req.backlog = backlog;

  bufs[0].iov_base = &req;
  bufs[0].iov_len = sizeof(req);

  return usrsock_do_request(conn, bufs, nitems(bufs));
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: usrsock_listen
 *
 * Description:
 *   To accept connections, a socket is first created with psock_socket(), a
 *   willingness to accept incoming connections and a queue limit for
 *   incoming connections are specified with psock_listen(), and then the
 *   connections are accepted with psock_accept().  For the case of AFINET
 *   and AFINET6 sockets, psock_listen() calls this function.  The
 *   psock_listen() call applies only to sockets of type SOCK_STREAM or
 *   SOCK_SEQPACKET.
 *
 * Parameters:
 *   psock    Reference to an internal, bound socket structure.
 *   backlog  The maximum length the queue of pending connections may grow.
 *            If a connection request arrives with the queue full, the client
 *            may receive an error with an indication of ECONNREFUSED or,
 *            if the underlying protocol supports retransmission, the request
 *            may be ignored so that retries succeed.
 *
 * Returned Value:
 *   On success, zero is returned. On error, a negated errno value is
 *   returned.  See listen() for the set of appropriate error values.
 *
 ****************************************************************************/

int usrsock_listen(FAR struct socket *psock, int backlog)
{
  FAR struct usrsock_conn_s *conn = psock->s_conn;
  struct usrsock_reqstate_s state =
  {
  };

  int ret;

  net_lock();

  if (conn->state == USRSOCK_CONN_STATE_UNINITIALIZED ||
      conn->state == USRSOCK_CONN_STATE_ABORTED)
    {
      /* Invalid state or closed by daemon. */

      ninfo("usockid=%d; listen() with uninitialized usrsock.\n",
            conn->usockid);

      ret = (conn->state == USRSOCK_CONN_STATE_ABORTED) ? -EPIPE :
            -ECONNREFUSED;
      goto errout_unlock;
    }

  if (conn->connected)
    {
      /* Already connected. */

      ret = -EISCONN;
      goto errout_unlock;
    }

  if (conn->state == USRSOCK_CONN_STATE_CONNECTING)
    {
      /* Already connecting. */

      ninfo("usockid=%d; socket already connecting.\n",
            conn->usockid);

      ret = -EALREADY;
      goto errout_unlock;
    }

  /* Set up event callback for usrsock. */

  ret = usrsock_setup_request_callback(conn, &state, listen_event,
                                       USRSOCK_EVENT_ABORT |
                                       USRSOCK_EVENT_REQ_COMPLETE);
  if (ret < 0)
    {
      nwarn("usrsock_setup_request_callback failed: %d\n", ret);

      goto errout_unlock;
    }

  /* Mark conn as listening(reuse connecting here) one. */

  conn->state = USRSOCK_CONN_STATE_CONNECTING;

  /* Send request. */

  ret = do_listen_request(conn, backlog);
  if (ret < 0)
    {
      goto errout_teardown;
    }

  /* Wait for completion of request (or signal). */

  ret = net_sem_wait(&state.recvsem);
  if (ret < 0)
    {
      /* Wait interrupted, exit early. */

      goto errout_teardown;
    }

  ret = state.result;

errout_teardown:
  usrsock_teardown_request_callback(&state);
errout_unlock:
  net_unlock();
  return ret;
}

#endif /* CONFIG_NET && CONFIG_NET_USRSOCK */
