/****************************************************************************
 * net/icmpv6/icmpv6_sockif.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>

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

#include <nuttx/mm/iob.h>
#include <nuttx/net/net.h>
#include <socket/socket.h>

#include "icmpv6/icmpv6.h"

#ifdef CONFIG_NET_ICMPv6_SOCKET

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

static int        icmpv6_setup(FAR struct socket *psock);
static sockcaps_t icmpv6_sockcaps(FAR struct socket *psock);
static void       icmpv6_addref(FAR struct socket *psock);
static int        icmpv6_listen(FAR struct socket *psock, int backlog);
static int        icmpv6_connect(FAR struct socket *psock,
                    FAR const struct sockaddr *addr, socklen_t addrlen);
static int        icmpv6_accept(FAR struct socket *psock,
                    FAR struct sockaddr *addr, FAR socklen_t *addrlen,
                    FAR struct socket *newsock);
static int        icmpv6_netpoll(FAR struct socket *psock,
                    FAR struct pollfd *fds, bool setup);
static int        icmpv6_close(FAR struct socket *psock);

/****************************************************************************
 * Public Data
 ****************************************************************************/

const struct sock_intf_s g_icmpv6_sockif =
{
  icmpv6_setup,       /* si_setup */
  icmpv6_sockcaps,    /* si_sockcaps */
  icmpv6_addref,      /* si_addref */
  NULL,               /* si_bind */
  NULL,               /* si_getsockname */
  NULL,               /* si_getpeername */
  icmpv6_listen,      /* si_listen */
  icmpv6_connect,     /* si_connect */
  icmpv6_accept,      /* si_accept */
  icmpv6_netpoll,     /* si_poll */
  icmpv6_sendmsg,     /* si_sendmsg */
  icmpv6_recvmsg,     /* si_recvmsg */
  icmpv6_close,       /* si_close */
  icmpv6_ioctl        /* si_ioctl */
};

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

/****************************************************************************
 * Name: icmpv6_setup
 *
 * Description:
 *   Called for socket() to verify that the provided socket type and
 *   protocol are usable by this address family.  Perform any family-
 *   specific socket fields.
 *
 * Input Parameters:
 *   psock    A pointer to a user allocated socket structure to be
 *            initialized.
 *
 * Returned Value:
 *   Zero (OK) is returned on success.  Otherwise, a negated errno value is
 *   returned.
 *
 ****************************************************************************/

static int icmpv6_setup(FAR struct socket *psock)
{
  /* SOCK_DGRAM or SOCK_CTRL and IPPROTO_ICMP6 are supported */

  if ((psock->s_type == SOCK_DGRAM || psock->s_type == SOCK_CTRL) &&
      psock->s_proto == IPPROTO_ICMP6)
    {
      /* Allocate the IPPROTO_ICMP6 socket connection structure and save in
       * the new socket instance.
       */

      FAR struct icmpv6_conn_s *conn = icmpv6_alloc();
      if (conn == NULL)
        {
          /* Failed to reserve a connection structure */

          return -ENOMEM;
        }

      /* Set the reference count on the connection structure.
       * This reference count will be incremented only if the socket is
       * dup'ed
       */

      DEBUGASSERT(conn->crefs == 0);
      conn->crefs = 1;

      /* Save the pre-allocated connection in the socket structure */

      psock->s_conn = conn;
      return OK;
    }
  else
    {
      return -EPROTONOSUPPORT;
    }
}

/****************************************************************************
 * Name: icmpv6_sockcaps
 *
 * Description:
 *   Return the bit encoded capabilities of this socket.
 *
 * Input Parameters:
 *   psock - Socket structure of the socket whose capabilities are being
 *           queried.
 *
 * Returned Value:
 *   The set of socket cababilities is returned.
 *
 ****************************************************************************/

static sockcaps_t icmpv6_sockcaps(FAR struct socket *psock)
{
  return SOCKCAP_NONBLOCKING;
}

/****************************************************************************
 * Name: icmpv6_addref
 *
 * Description:
 *   Increment the reference count on the underlying connection structure.
 *
 * Input Parameters:
 *   psock - Socket structure of the socket whose reference count will be
 *           incremented.
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void icmpv6_addref(FAR struct socket *psock)
{
  FAR struct icmpv6_conn_s *conn;

  DEBUGASSERT(psock != NULL && psock->s_conn != NULL);

  conn = psock->s_conn;
  DEBUGASSERT(conn->crefs > 0 && conn->crefs < 255);
  conn->crefs++;
}

/****************************************************************************
 * Name: icmpv6_connect
 *
 * Description:
 *   icmpv6_connect() connects the local socket referred to by the structure
 *   'psock' to the address specified by 'addr'. The addrlen argument
 *   specifies the size of 'addr'.  The format of the address in 'addr' is
 *   determined by the address space of the socket 'psock'.
 *
 *   If the socket 'psock' is of type SOCK_DGRAM then 'addr' is the address
 *   to which datagrams are sent by default, and the only address from which
 *   datagrams are received. If the socket is of type SOCK_STREAM or
 *   SOCK_SEQPACKET, this call attempts to make a connection to the socket
 *   that is bound to the address specified by 'addr'.
 *
 *   Generally, connection-based protocol sockets may successfully
 *   icmpv6_connect() only once; connectionless protocol sockets may use
 *   icmpv6_connect() multiple times to change their association.
 *   Connectionless sockets may dissolve the association by connecting to
 *   an address with the sa_family member of sockaddr set to AF_UNSPEC.
 *
 * Input Parameters:
 *   psock     Pointer to a socket structure initialized by psock_socket()
 *   addr      Server address (form depends on type of socket)
 *   addrlen   Length of actual 'addr'
 *
 * Returned Value:
 *   0 on success; a negated errno value on failure.  See connect() for the
 *   list of appropriate errno values to be returned.
 *
 ****************************************************************************/

static int icmpv6_connect(FAR struct socket *psock,
                       FAR const struct sockaddr *addr, socklen_t addrlen)
{
  return -EAFNOSUPPORT;
}

/****************************************************************************
 * Name: icmpv6_accept
 *
 * Description:
 *   The icmpv6_accept function is used with connection-based socket types
 *   (SOCK_STREAM, SOCK_SEQPACKET and SOCK_RDM). It extracts the first
 *   connection request on the queue of pending connections, creates a new
 *   connected socket with mostly the same properties as 'sockfd', and
 *   allocates a new socket descriptor for the socket, which is returned. The
 *   newly created socket is no longer in the listening state. The original
 *   socket 'sockfd' is unaffected by this call.  Per file descriptor flags
 *   are not inherited across an icmpv6_accept.
 *
 *   The 'sockfd' argument is a socket descriptor that has been created with
 *   socket(), bound to a local address with bind(), and is listening for
 *   connections after a call to listen().
 *
 *   On return, the 'addr' structure is filled in with the address of the
 *   connecting entity. The 'addrlen' argument initially contains the size
 *   of the structure pointed to by 'addr'; on return it will contain the
 *   actual length of the address returned.
 *
 *   If no pending connections are present on the queue, and the socket is
 *   not marked as non-blocking, icmpv6_accept blocks the caller until a
 *   connection is present. If the socket is marked non-blocking and no
 *   pending connections are present on the queue, icmpv6_accept returns
 *   EAGAIN.
 *
 * Input Parameters:
 *   psock    Reference to the listening socket structure
 *   addr     Receives the address of the connecting client
 *   addrlen  Input: allocated size of 'addr',
 *            Return: returned size of 'addr'
 *   newsock  Location to return the accepted socket information.
 *
 * Returned Value:
 *   Returns 0 (OK) on success.  On failure, it returns a negated errno
 *   value.  See accept() for a description of the appropriate error value.
 *
 * Assumptions:
 *   The network is locked.
 *
 ****************************************************************************/

static int icmpv6_accept(FAR struct socket *psock, FAR struct sockaddr *addr,
                      FAR socklen_t *addrlen, FAR struct socket *newsock)
{
  return -EAFNOSUPPORT;
}

/****************************************************************************
 * Name: icmpv6_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 raw
 *   packet sockets, psock_listen() calls this function.  The psock_listen()
 *   call applies only to sockets of type SOCK_STREAM or SOCK_SEQPACKET.
 *
 * Input Parameters:
 *   psock    Reference to an internal, boound 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 icmpv6_listen(FAR struct socket *psock, int backlog)
{
  return -EOPNOTSUPP;
}

/****************************************************************************
 * Name: icmpv6_netpoll
 *
 * Description:
 *   The standard poll() operation redirects operations on socket descriptors
 *   to net_poll which, indiectly, calls to function.
 *
 * Input Parameters:
 *   psock - An instance of the internal socket structure.
 *   fds   - The structure describing the events to be monitored, OR NULL if
 *           this is a request to stop monitoring events.
 *   setup - true: Setup up the poll; false: Teardown the poll
 *
 * Returned Value:
 *  0: Success; Negated errno on failure
 *
 ****************************************************************************/

static int icmpv6_netpoll(FAR struct socket *psock, FAR struct pollfd *fds,
                        bool setup)
{
  /* Check if we are setting up or tearing down the poll */

  if (setup)
    {
      /* Perform the ICMPv6 poll() setup */

      return icmpv6_pollsetup(psock, fds);
    }
  else
    {
      /* Perform the ICMPv6 poll() teardown */

      return icmpv6_pollteardown(psock, fds);
    }
}

/****************************************************************************
 * Name: icmpv6_close
 *
 * Description:
 *   Performs the close operation on a raw packet socket instance
 *
 * Input Parameters:
 *   psock   Socket instance
 *
 * Returned Value:
 *   0 on success; a negated errno value is returned on any failure.
 *
 * Assumptions:
 *
 ****************************************************************************/

static int icmpv6_close(FAR struct socket *psock)
{
  FAR struct icmpv6_conn_s *conn;

  DEBUGASSERT(psock != NULL && psock->s_conn != NULL);
  conn = psock->s_conn;

  /* Is this the last reference to the connection structure (there could be\
   * more if the socket was dup'ed).
   */

  DEBUGASSERT(conn->crefs > 0);

  if (conn->crefs <= 1)
    {
      /* Yes... free any read-ahead data */

      iob_free_queue(&conn->readahead);

      /* Then free the connection structure */

      conn->crefs = 0;             /* No more references on the connection */
      icmpv6_free(psock->s_conn);  /* Free network resources */
    }
  else
    {
      /* No.. Just decrement the reference count */

      conn->crefs--;
    }

  return OK;
}

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

#endif /* CONFIG_NET_ICMPv6_SOCKET */