/****************************************************************************
 * net/socket/sendto.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 <nuttx/config.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/cancelpt.h>
#include <nuttx/kmalloc.h>
#include <nuttx/net/net.h>

#include "socket/socket.h"

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

/****************************************************************************
 * Name: psock_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
 *   to       Address of recipient
 *   tolen    The length of the address structure
 *
 * Returned Value:
 *   On success, returns the number of characters sent.  On a negated errno
 *   value is returned.  One of:
 *
 *   EAGAIN or EWOULDBLOCK
 *     The socket is marked non-blocking and the requested operation
 *     would block.
 *   EBADF
 *     An invalid descriptor was specified.
 *   ECONNRESET
 *     Connection reset by peer.
 *   EDESTADDRREQ
 *     The socket is not connection-mode, and no peer address is set.
 *   EFAULT
 *      An invalid user space address was specified for a parameter.
 *   EINTR
 *      A signal occurred before any data was transmitted.
 *   EINVAL
 *      Invalid argument passed.
 *   EISCONN
 *     The connection-mode socket was connected already but a recipient
 *     was specified. (Now either this error is returned, or the recipient
 *     specification is ignored.)
 *   EMSGSIZE
 *     The socket type requires that message be sent atomically, and the
 *     size of the message to be sent made this impossible.
 *   ENOBUFS
 *     The output queue for a network interface was full. This generally
 *     indicates that the interface has stopped sending, but may be
 *     caused by transient congestion.
 *   ENOMEM
 *     No memory available.
 *   ENOTCONN
 *     The socket is not connected, and no target has been given.
 *   ENOTSOCK
 *     The argument s is not a socket.
 *   EOPNOTSUPP
 *     Some bit in the flags argument is inappropriate for the socket
 *     type.
 *   EPIPE
 *     The local end has been shut down on a connection oriented socket.
 *     In this case the process will also receive a SIGPIPE unless
 *     MSG_NOSIGNAL is set.
 *
 ****************************************************************************/

ssize_t psock_sendto(FAR struct socket *psock, FAR const void *buf,
                     size_t len, int flags, FAR const struct sockaddr *to,
                     socklen_t tolen)
{
  struct iovec iov;
  struct msghdr msg;

  if (tolen != 0 && to == NULL)
    {
      return -EINVAL;
    }

  iov.iov_base = (FAR void *)buf;
  iov.iov_len = len;
  msg.msg_name = (FAR struct sockaddr *)to;
  msg.msg_namelen = tolen;
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;
  msg.msg_control = NULL;
  msg.msg_controllen = 0;
  msg.msg_flags = 0;

  /* And let psock_sendmsg do all of the work */

  return psock_sendmsg(psock, &msg, flags);
}

/****************************************************************************
 * Name: 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:
 *   sockfd   Socket descriptor of socket
 *   buf      Data to send
 *   len      Length of data to send
 *   flags    Send flags
 *   to       Address of recipient
 *   tolen    The length of the address structure
 *
 * Returned Value:
 *   On success, returns the number of characters sent.  On error,
 *   -1 is returned, and errno is set appropriately:
 *
 *   EAGAIN or EWOULDBLOCK
 *     The socket is marked non-blocking and the requested operation
 *     would block.
 *   EBADF
 *     An invalid descriptor was specified.
 *   ECONNRESET
 *     Connection reset by peer.
 *   EDESTADDRREQ
 *     The socket is not connection-mode, and no peer address is set.
 *   EFAULT
 *      An invalid user space address was specified for a parameter.
 *   EINTR
 *      A signal occurred before any data was transmitted.
 *   EINVAL
 *      Invalid argument passed.
 *   EISCONN
 *     The connection-mode socket was connected already but a recipient
 *     was specified. (Now either this error is returned, or the recipient
 *     specification is ignored.)
 *   EMSGSIZE
 *     The socket type requires that message be sent atomically, and the
 *     size of the message to be sent made this impossible.
 *   ENOBUFS
 *     The output queue for a network interface was full. This generally
 *     indicates that the interface has stopped sending, but may be
 *     caused by transient congestion.
 *   ENOMEM
 *     No memory available.
 *   ENOTCONN
 *     The socket is not connected, and no target has been given.
 *   ENOTSOCK
 *     The argument s is not a socket.
 *   EOPNOTSUPP
 *     Some bit in the flags argument is inappropriate for the socket
 *     type.
 *   EPIPE
 *     The local end has been shut down on a connection oriented socket.
 *     In this case the process will also receive a SIGPIPE unless
 *     MSG_NOSIGNAL is set.
 *
 ****************************************************************************/

ssize_t sendto(int sockfd, FAR const void *buf, size_t len, int flags,
               FAR const struct sockaddr *to, socklen_t tolen)
{
  FAR struct socket *psock;
  FAR struct file *filep;
  ssize_t ret;
#ifdef CONFIG_BUILD_KERNEL
  struct sockaddr_storage kaddr;
  FAR void *kbuf;
#endif

  /* sendto() is a cancellation point */

  enter_cancellation_point();

#ifdef CONFIG_BUILD_KERNEL
  /* Allocate memory and copy user buffer to kernel */

  kbuf = kmm_malloc(len);
  if (!kbuf)
    {
      /* Out of memory */

      ret = -ENOMEM;
      goto errout_with_cancelpt;
    }

  memcpy(kbuf, buf, len);
  buf = kbuf;

  /* Copy the address data to kernel */

  if (to)
    {
      memcpy(&kaddr, to, tolen);
      to = (FAR const struct sockaddr *)&kaddr;
    }
#endif

  /* Get the underlying socket structure */

  ret = sockfd_socket(sockfd, &filep, &psock);

  /* And let psock_sendto do all of the work */

  if (ret == OK)
    {
      ret = psock_sendto(psock, buf, len, flags, to, tolen);
      fs_putfilep(filep);
    }

#ifdef CONFIG_BUILD_KERNEL
  kmm_free(kbuf);

errout_with_cancelpt:
#endif

  leave_cancellation_point();

  if (ret < 0)
    {
      set_errno(-ret);
      ret = ERROR;
    }

  return ret;
}