text: /**************************************************************************/
  /*                                                                        */
  /*       Copyright (c) Microsoft Corporation. All rights reserved.        */
  /*                                                                        */
  /*       This software is licensed under the Microsoft Software License   */
  /*       Terms for Microsoft Azure RTOS. Full text of the license can be  */
  /*       found in the LICENSE file at https://aka.ms/AzureRTOS_EULA       */
  /*       and in the root directory of this software.                      */
  /*                                                                        */
  /**************************************************************************/
  
  
  /**************************************************************************/
  /**************************************************************************/
  /**                                                                       */
  /** NetX Component                                                        */
  /**                                                                       */
  /**   User Datagram Protocol (UDP)                                        */
  /**                                                                       */
  /**************************************************************************/
  /**************************************************************************/
  
  #define NX_SOURCE_CODE
  
  
  /* Include necessary system files.  */
  
  #include "nx_api.h"
  #include "nx_udp.h"
  
  
  /**************************************************************************/
  /*                                                                        */
  /*  FUNCTION                                               RELEASE        */
  /*                                                                        */
  /*    _nx_udp_socket_create                               PORTABLE C      */
  /*                                                           6.1          */
  /*  AUTHOR                                                                */
  /*                                                                        */
  /*    Yuxin Zhou, Microsoft Corporation                                   */
  /*                                                                        */
  /*  DESCRIPTION                                                           */
  /*                                                                        */
  /*    This function creates a UDP socket for the specified IP instance.   */
  /*                                                                        */
  /*  INPUT                                                                 */
  /*                                                                        */
  /*    ip_ptr                                IP instance pointer           */
  /*    socket_ptr                            Pointer to new UDP socket     */
  /*    name                                  Name of new UDP socket        */
  /*    type_of_service                       Type of service for this UDP  */
  /*                                            socket                      */
  /*    fragment                              Flag to enable IP fragmenting */
  /*    time_to_live                          Time to live value for socket */
  /*    queue_maximum                         Maximum depth of receive queue*/
  /*                                                                        */
  /*  OUTPUT                                                                */
  /*                                                                        */
  /*    status                                Completion status             */
  /*                                                                        */
  /*  CALLS                                                                 */
  /*                                                                        */
  /*    tx_mutex_get                          Obtain protection mutex       */
  /*    tx_mutex_put                          Release protection mutex      */
  /*                                                                        */
  /*  CALLED BY                                                             */
  /*                                                                        */
  /*    Application Code                                                    */
  /*                                                                        */
  /*  RELEASE HISTORY                                                       */
  /*                                                                        */
  /*    DATE              NAME                      DESCRIPTION             */
  /*                                                                        */
  /*  05-19-2020     Yuxin Zhou               Initial Version 6.0           */
  /*  09-30-2020     Yuxin Zhou               Modified comment(s),          */
  /*                                            resulting in version 6.1    */
  /*                                                                        */
  /**************************************************************************/
  UINT  _nx_udp_socket_create(NX_IP *ip_ptr, NX_UDP_SOCKET *socket_ptr, CHAR *name,
                              ULONG type_of_service, ULONG fragment, UINT time_to_live, ULONG queue_maximum)
  {
  TX_INTERRUPT_SAVE_AREA
  
  NX_UDP_SOCKET *tail_ptr;
  
  
      /* Initialize the TCP control block to zero.  */
      memset((void *)socket_ptr, 0, sizeof(NX_UDP_SOCKET));
  
      /* Fill in the basic information in the new UDP socket structure.  */
  
      /* Remember the associated IP structure.  */
      socket_ptr -> nx_udp_socket_ip_ptr =  ip_ptr;
  
      /* Save the UDP socket's name.  */
      socket_ptr -> nx_udp_socket_name =  name;
  
      /* Save the type of service input parameter.  */
      socket_ptr -> nx_udp_socket_type_of_service =  type_of_service;
  
      /* Save the fragment input parameter.  */
      socket_ptr -> nx_udp_socket_fragment_enable =  fragment & NX_DONT_FRAGMENT;
  
      /* Save the time-to-live input parameter.  */
      socket_ptr -> nx_udp_socket_time_to_live =  time_to_live;
  
      /* By default, have UDP checksum logic enabled.  To disable checksum logic, the
         application must call the nx_udp_checksum disable function for this UDP socket.  */
      socket_ptr -> nx_udp_socket_disable_checksum =  NX_FALSE;
  
      /* Clear the socket bind in progress flag.  */
      socket_ptr -> nx_udp_socket_bind_in_progress =  NX_FALSE;
  
      /* Set various list pointers to NULL.  */
      socket_ptr -> nx_udp_socket_bound_next =            NX_NULL;
      socket_ptr -> nx_udp_socket_bound_previous =        NX_NULL;
      socket_ptr -> nx_udp_socket_bind_suspension_list =  NX_NULL;
      socket_ptr -> nx_udp_socket_bind_suspended_count =  0;
  
      /* Initialize the receive queue parameters.  */
      socket_ptr -> nx_udp_socket_receive_count =         0;
      socket_ptr -> nx_udp_socket_queue_maximum =         queue_maximum;
      socket_ptr -> nx_udp_socket_receive_head =          NX_NULL;
      socket_ptr -> nx_udp_socket_receive_tail =          NX_NULL;
  
      /* Clear the receive notify function pointer.  */
      socket_ptr -> nx_udp_receive_callback =             NX_NULL;
  
      /* If trace is enabled, register this object.  */
      NX_TRACE_OBJECT_REGISTER(NX_TRACE_OBJECT_TYPE_UDP_SOCKET, socket_ptr, name, type_of_service, queue_maximum);
  
      /* If trace is enabled, insert this event into the trace buffer.  */
      NX_TRACE_IN_LINE_INSERT(NX_TRACE_UDP_SOCKET_CREATE, ip_ptr, socket_ptr, type_of_service, queue_maximum, NX_TRACE_IP_EVENTS, 0, 0);
  
      /* Obtain the IP mutex so we can add socket to IP structure.  */
      tx_mutex_get(&(ip_ptr -> nx_ip_protection), TX_WAIT_FOREVER);
  
      /* Disable interrupts while we link the new UDP socket to the IP structure.  */
      TX_DISABLE
  
      /* Load the UDP ID field in the UDP control block.  */
      socket_ptr -> nx_udp_socket_id =  NX_UDP_ID;
  
      /* Place the new UDP control block on the list of created UDP sockets for this IP.  First,
         check for an empty list.  */
      if (ip_ptr -> nx_ip_udp_created_sockets_ptr)
      {
  
          /* Pickup tail pointer.  */
          tail_ptr =  (ip_ptr -> nx_ip_udp_created_sockets_ptr) -> nx_udp_socket_created_previous;
  
          /* Place the new UDP socket control block in the list.  */
          (ip_ptr -> nx_ip_udp_created_sockets_ptr) -> nx_udp_socket_created_previous =  socket_ptr;
          tail_ptr ->  nx_udp_socket_created_next =  socket_ptr;
  
          /* Setup this UDP socket's created links.  */
          socket_ptr -> nx_udp_socket_created_previous =  tail_ptr;
          socket_ptr -> nx_udp_socket_created_next =      ip_ptr -> nx_ip_udp_created_sockets_ptr;
      }
      else
      {
  
          /* The created UDP socket list is empty.  Add UDP socket control block to empty list.  */
          ip_ptr -> nx_ip_udp_created_sockets_ptr =       socket_ptr;
          socket_ptr -> nx_udp_socket_created_previous =  socket_ptr;
          socket_ptr -> nx_udp_socket_created_next =      socket_ptr;
      }
  
      /* Increment the created UDP socket counter.  */
      ip_ptr -> nx_ip_udp_created_sockets_count++;
  
      /* Restore previous interrupt posture.  */
      TX_RESTORE
  
      /* Release the IP protection mutex.  */
      tx_mutex_put(&(ip_ptr -> nx_ip_protection));
  
      /* Return successful completion.  */
      return(NX_SUCCESS);
  }
  
  