/****************************************************************************
 * net/usrsock/usrsock_sendto.c
 *
 *  Copyright (C) 2015, 2017 Haltian Ltd. All rights reserved.
 *  Author: Jussi Kivilinna <jussi.kivilinna@haltian.com>
 *
 * 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 <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_USRSOCK)

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

#include <arch/irq.h>

#include <sys/socket.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include <nuttx/net/usrsock.h>

#include "usrsock/usrsock.h"

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

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

  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;

      if (pstate->result >= 0 || pstate->result == -EAGAIN)
        {
          /* After reception of data, mark input not ready. Daemon will
           * send event to restore this flag. */

          conn->flags &= ~USRSOCK_EVENT_SENDTO_READY;
        }

      /* 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_REMOTE_CLOSED)
    {
      ninfo("remote closed.\n");

      pstate->result = -EPIPE;

      /* 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_SENDTO_READY)
    {
      ninfo("sendto ready.\n");

      /* Do not let other waiters to claim new data. */

      flags &= ~USRSOCK_EVENT_SENDTO_READY;

      /* 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_sendto_request
 ****************************************************************************/

static int do_sendto_request(FAR struct usrsock_conn_s *conn,
                             FAR const void *buf, size_t buflen,
                             FAR const struct sockaddr *addr,
                             socklen_t addrlen)
{
  struct usrsock_request_sendto_s req = {};
  struct iovec bufs[3];

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

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

  /* Prepare request for daemon to read. */

  req.head.reqid = USRSOCK_REQUEST_SENDTO;
  req.usockid = conn->usockid;
  req.addrlen = addrlen;
  req.buflen = buflen;

  bufs[0].iov_base = (FAR void *)&req;
  bufs[0].iov_len = sizeof(req);
  bufs[1].iov_base = (FAR void *)addr;
  bufs[1].iov_len = addrlen;
  bufs[2].iov_base = (FAR void *)buf;
  bufs[2].iov_len = buflen;

  return usrsockdev_do_request(conn, bufs, ARRAY_SIZE(bufs));
}

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

/****************************************************************************
 * Name: usrsock_sendto
 *
 * Description:
 *   If sendto() is used on a connection-mode (SOCK_STREAM, SOCK_SEQPACKET)
 *   socket, the parameters to and 'tolen' are ignored (and the error EISCONN
 *   may be returned when they are not NULL and 0), and the error ENOTCONN is
 *   returned when the socket was not actually connected.
 *
 * Input Parameters:
 *   psock    A pointer to a NuttX-specific, internal socket structure
 *   buf      Data to send
 *   len      Length of data to send
 *   flags    Send flags (ignored)
 *   to       Address of recipient
 *   tolen    The length of the address structure
 *
 ****************************************************************************/

ssize_t usrsock_sendto(FAR struct socket *psock, FAR const void *buf,
                       size_t len, int flags, FAR const struct sockaddr *to,
                       socklen_t tolen)
{
  FAR struct usrsock_conn_s *conn = psock->s_conn;
  struct usrsock_reqstate_s state = {};
  ssize_t ret;
#ifdef CONFIG_NET_SOCKOPTS
  struct timespec abstime;
#endif
  struct timespec *ptimeo = NULL;

  DEBUGASSERT(conn);

  net_lock();

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

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

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

  if (conn->type == SOCK_STREAM || conn->type == SOCK_SEQPACKET)
    {
      if (!conn->connected)
        {
          if (conn->state == USRSOCK_CONN_STATE_CONNECTING)
            {
              /* Connecting. */

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

              ret = -EAGAIN;
              goto errout_unlock;
            }
          else
            {
              /* Not connected. */

              ret = -ENOTCONN;
              goto errout_unlock;
            }
        }

      if (to || tolen)
        {
          /* Address provided for connection-mode socket */

          ret = -EISCONN;
          goto errout_unlock;
        }
    }

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

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

      ret = -EAGAIN;
      goto errout_unlock;
    }

#ifdef CONFIG_NET_SOCKOPTS
  if (psock->s_sndtimeo != 0)
    {
      DEBUGVERIFY(clock_gettime(CLOCK_REALTIME, &abstime));

      /* Prepare timeout value for sendto. */

      abstime.tv_sec += psock->s_sndtimeo / DSEC_PER_SEC;
      abstime.tv_nsec += (psock->s_sndtimeo % DSEC_PER_SEC) * NSEC_PER_DSEC;
      if (abstime.tv_nsec >= NSEC_PER_SEC)
        {
          abstime.tv_sec++;
          abstime.tv_nsec -= NSEC_PER_SEC;
        }

      ptimeo = &abstime;
    }
#endif

  do
    {
      /* Check if remote end has closed connection. */

      if (conn->flags & USRSOCK_EVENT_REMOTE_CLOSED)
        {
          ninfo("usockid=%d; remote closed.\n", conn->usockid);

          ret = -EPIPE;
          goto errout_unlock;
        }

      /* Check if need to wait for send to become ready. */

      if (!(conn->flags & USRSOCK_EVENT_SENDTO_READY))
        {
          if (_SS_ISNONBLOCK(psock->s_flags))
            {
              /* Send busy at daemon side. */

              ret = -EAGAIN;
              goto errout_unlock;
            }

          /* Wait send to become ready. */

          ret = usrsock_setup_request_callback(conn, &state, sendto_event,
                                               USRSOCK_EVENT_ABORT |
                                               USRSOCK_EVENT_SENDTO_READY |
                                               USRSOCK_EVENT_REMOTE_CLOSED);
          if (ret < 0)
            {
              nwarn("usrsock_setup_request_callback failed: %d\n", ret);
              goto errout_unlock;
            }

          /* Wait for send-ready (or abort, or timeout, or signal). */

          ret = net_timedwait(&state.recvsem, ptimeo);
          if (ret < 0)
            {
              if (ret == -ETIMEDOUT)
                {
                  ninfo("sendto timedout\n");

                  ret = -EAGAIN;
                }
              else if (ret == -EINTR)
                {
                  ninfo("sendto interrupted\n");
                }
              else
                {
                  nerr("net_timedwait errno: %d\n", ret);
                  DEBUGASSERT(false);
                }
            }

          usrsock_teardown_request_callback(&state);

          /* Did wait timeout or got signal? */

          if (ret != 0)
            {
              goto errout_unlock;
            }

          /* Was socket aborted? */

          if (conn->state == USRSOCK_CONN_STATE_ABORTED)
            {
              ret = -EPIPE;
              goto errout_unlock;
            }

          /* Did remote disconnect? */

          if (conn->flags & USRSOCK_EVENT_REMOTE_CLOSED)
            {
              ret = -EPIPE;
              goto errout_unlock;
            }

          DEBUGASSERT(conn->flags & USRSOCK_EVENT_SENDTO_READY);
        }

      /* Set up event callback for usrsock. */

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

      /* Request user-space daemon to close socket. */

      ret = do_sendto_request(conn, buf, len, to, tolen);
      if (ret >= 0)
        {
          /* Wait for completion of request. */

          while ((ret = net_lockedwait(&state.recvsem)) < 0)
            {
              DEBUGASSERT(ret == -EINTR || ret == -ECANCELED);
            }

          ret = state.result;

          DEBUGASSERT(ret <= (ssize_t)len);
        }

      usrsock_teardown_request_callback(&state);
    }
  while (ret == -EAGAIN);

errout_unlock:
  net_unlock();
  return ret;
}

#endif /* CONFIG_NET && CONFIG_NET_USRSOCK */