nuttx/net/socket/getsockopt.c

/****************************************************************************
 * net/socket/getsockopt.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_SOCKOPTS)

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

#include "socket/socket.h"
#include "utils/utils.h"

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

/****************************************************************************
 * Name: psock_socketlevel_option
 *
 * Description:
 *   getsockopt() retrieve the value for the option specified by the
 *   'option' argument for the socket specified by the 'psock' argument.  If
 *   the size of the option value is greater than 'value_len', the value
 *   stored in the object pointed to by the 'value' argument will be silently
 *   truncated. Otherwise, the length pointed to by the 'value_len' argument
 *   will be modified to indicate the actual length of the 'value'.
 *
 *   The 'level' argument specifies the protocol level of the option. To
 *   retrieve options at the socket level, specify the level argument as
 *   SOL_SOCKET; to retrieve options at the TCP-protocol level, the level
 *   argument is SOL_TCP.
 *
 *   See <sys/socket.h> a complete list of values for the socket-level
 *   'option' argument.  Protocol-specific options are are protocol specific
 *   header files (such as netinet/tcp.h for the case of the TCP protocol).
 *
 * Input Parameters:
 *   psock     Socket structure of the socket to query
 *   level     Protocol level to set the option
 *   option    identifies the option to get
 *   value     Points to the argument value
 *   value_len The length of the argument value
 *
 * Returned Value:
 *   Returns zero (OK) on success.  On failure, it returns a negated errno
 *   value to indicate the nature of the error.  See psock_getsockopt() for
 *   the complete list of appropriate return error codes.
 *
 ****************************************************************************/

static int psock_socketlevel_option(FAR struct socket *psock, int option,
                                    FAR void *value,
                                    FAR socklen_t *value_len)
{
  FAR struct socket_conn_s *conn = psock->s_conn;

  /* Verify that the socket option if valid (but might not be supported ) */

  if (!value || !value_len)
    {
      return -EINVAL;
    }

  /* Process the options always handled locally */

  switch (option)
    {
      /* The following are valid only if the OS CLOCK feature is enabled */

      case SO_RCVTIMEO:
      case SO_SNDTIMEO:
        {
          socktimeo_t timeo;

          /* Verify that option is the size of an 'int'.  Should also check
           * that 'value' is properly aligned for an 'int'
           */

          if (*value_len < sizeof(struct timeval))
            {
              return -EINVAL;
            }

          /* Get the timeout value.  This is a atomic operation and should
         * require no special operation.
         */

          if (option == SO_RCVTIMEO)
            {
              timeo = conn->s_rcvtimeo;
            }
          else
            {
              timeo = conn->s_sndtimeo;
            }

          /* Then return the timeout value to the caller */

          net_dsec2timeval(timeo, (FAR struct timeval *)value);
          *value_len = sizeof(struct timeval);
          return OK;
        }

      case SO_ACCEPTCONN: /* Reports whether socket listening is enabled */
        {
          if (*value_len < sizeof(int))
            {
              return -EINVAL;
            }

          *(FAR int *)value = _SS_ISLISTENING(conn->s_flags);
          *value_len        = sizeof(int);
        }
        break;

      /* The following options take a point to an integer boolean value.
       * We will blindly report the bit here although the implementation
       * is outside of the scope of getsockopt.
       */

      case SO_BROADCAST:  /* Permits sending of broadcast messages */
      case SO_DEBUG:      /* Enables recording of debugging information */
      case SO_DONTROUTE:  /* Requests outgoing messages bypass standard routing */
      case SO_KEEPALIVE:  /* Verifies TCP connections active by enabling the
                           * periodic transmission of probes */
      case SO_OOBINLINE:  /* Leaves received out-of-band data inline */
      case SO_REUSEADDR:  /* Allow reuse of local addresses */
        {
          sockopt_t optionset;

          /* Verify that option is the size of an 'int'.  Should also check
           * that 'value' is properly aligned for an 'int'
           */

          if (*value_len < sizeof(int))
            {
              return -EINVAL;
           }

          /* Sample the current options.  This is atomic operation and so
           * should not require any special steps for thread safety. We
           * this outside of the macro because you can never be sure what
           * a macro will do.
           */

          optionset         = conn->s_options;
          *(FAR int *)value = _SO_GETOPT(optionset, option);
          *value_len        = sizeof(int);
        }
        break;

      case SO_TYPE:       /* Reports the socket type */
        {
          /* Verify that option is the size of an 'int'.  Should also check
           * that 'value' is properly aligned for an 'int'
           */

          if (*value_len < sizeof(int))
            {
              return -EINVAL;
            }

          /* Return the socket type */

          *(FAR int *)value = psock->s_type;
          *value_len        = sizeof(int);
        }
        break;

      case SO_ERROR:      /* Reports and clears error status. */
        {
          if (*value_len != sizeof(int))
            {
              return -EINVAL;
            }

          *(FAR int *)value = (int)conn->s_error;
          conn->s_error = 0;
        }
        break;

      default:
        return -ENOPROTOOPT;
    }

  return OK;
}

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

/****************************************************************************
 * Name: psock_getsockopt
 *
 * Description:
 *   getsockopt() retrieve the value for the option specified by the
 *   'option' argument for the socket specified by the 'psock' argument.  If
 *   the size of the option value is greater than 'value_len', the value
 *   stored in the object pointed to by the 'value' argument will be silently
 *   truncated. Otherwise, the length pointed to by the 'value_len' argument
 *   will be modified to indicate the actual length of the 'value'.
 *
 *   The 'level' argument specifies the protocol level of the option. To
 *   retrieve options at the socket level, specify the level argument as
 *   SOL_SOCKET; to retrieve options at the TCP-protocol level, the level
 *   argument is SOL_TCP.
 *
 *   See <sys/socket.h> a complete list of values for the socket-level
 *   'option' argument.  Protocol-specific options are are protocol specific
 *   header files (such as netinet/tcp.h for the case of the TCP protocol).
 *
 * Input Parameters:
 *   psock     Socket structure of the socket to query
 *   level     Protocol level to set the option
 *   option    identifies the option to get
 *   value     Points to the argument value
 *   value_len The length of the argument value
 *
 * Returned Value:
 *   Returns zero (OK) on success.  On failure, it returns a negated errno
 *   value to indicate the nature of the error.
 *
 *   EINVAL
 *     The specified option is invalid at the specified socket 'level' or the
 *     socket has been shutdown.
 *   ENOPROTOOPT
 *     The 'option' is not supported by the protocol.
 *   ENOTSOCK
 *     The 'psock' argument does not refer to a socket.
 *   ENOBUFS
 *     Insufficient resources are available in the system to complete the
 *     call.
 *
 ****************************************************************************/

int psock_getsockopt(FAR struct socket *psock, int level, int option,
                     FAR void *value, FAR socklen_t *value_len)
{
  int ret = -ENOPROTOOPT;

  /* Verify that the sockfd corresponds to valid, allocated socket */

  if (psock == NULL || psock->s_conn == NULL)
    {
      return -EBADF;
    }

  /* Perform the socket interface operation */

  if (psock->s_sockif->si_getsockopt != NULL)
    {
      ret = psock->s_sockif->si_getsockopt(psock, level, option,
                                           value, value_len);
    }

  /* Try socket level if the socket interface operation is not available */

  if (ret == -ENOPROTOOPT && level == SOL_SOCKET)
    {
      ret = psock_socketlevel_option(psock, option, value, value_len);
    }

  /* -ENOTTY really mean -ENOPROTOOPT, but skip the default action */

  else if (ret == -ENOTTY)
    {
      ret = -ENOPROTOOPT;
    }

  return ret;
}

/****************************************************************************
 * Name: getsockopt
 *
 * Description:
 *   getsockopt() retrieve the value for the option specified by the
 *   'option' argument for the socket specified by the 'sockfd' argument. If
 *   the size of the option value is greater than 'value_len', the value
 *   stored in the object pointed to by the 'value' argument will be silently
 *   truncated. Otherwise, the length pointed to by the 'value_len' argument
 *   will be modified to indicate the actual length of the 'value'.
 *
 *   The 'level' argument specifies the protocol level of the option. To
 *   retrieve options at the socket level, specify the level argument as
 *   SOL_SOCKET; to retrieve options at the TCP-protocol level, the level
 *   argument is SOL_TCP.
 *
 *   See <sys/socket.h> a complete list of values for the socket-level
 *   'option' argument.  Protocol-specific options are are protocol specific
 *   header files (such as netinet/tcp.h for the case of the TCP protocol).
 *
 * Input Parameters:
 *   sockfd    Socket descriptor of socket
 *   level     Protocol level to set the option
 *   option    identifies the option to get
 *   value     Points to the argument value
 *   value_len The length of the argument value
 *
 * Returned Value:
 *   Returns zero (OK) on success.  On failure, -1 (ERROR) is returned and th
 *   errno variable is set appropriately:
 *
 *   EBADF
 *     The 'sockfd' argument is not a valid socket descriptor.
 *   EINVAL
 *     The specified option is invalid at the specified socket 'level' or the
 *     socket has been shutdown.
 *   ENOPROTOOPT
 *     The 'option' is not supported by the protocol.
 *   ENOTSOCK
 *     The 'sockfd' argument does not refer to a socket.
 *   ENOBUFS
 *     Insufficient resources are available in the system to complete the
 *     call.
 *
 ****************************************************************************/

int getsockopt(int sockfd, int level, int option,
               void *value, socklen_t *value_len)
{
  FAR struct socket *psock;
  int ret;

  /* Get the underlying socket structure */

  ret = sockfd_socket(sockfd, &psock);

  /* Then let psock_getsockopt() do all of the work */

  if (ret == OK)
    {
      ret = psock_getsockopt(psock, level, option, value, value_len);
    }

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

  return ret;
}

#endif /* CONFIG_NET && CONFIG_NET_SOCKOPTS */