odh.c

mcf5307实验源代码

/*  No inputs to the function                                               */
/*                                                                          */
/* OUTPUTS                                                                  */
/*                                                                          */
/*  No outputs from this function                                           */
/*                                                                          */
/* HISTORY                                                                  */
/*                                                                          */
/*  NAME                   DATE        REMARKS                              */
/*                                                                          */
/*  Glen Johnson         03/13/95    Initial version.                       */
/*                                                                          */
/****************************************************************************/
int16 NU_Deallocate_Buffer(int16 socketd, char *buffer)
{
    struct pqueue HUGE * item;
    struct pqueue HUGE * buf_ptr;
    int16     return_status;


    /*  Validate the socket number.  */
    if ((socketd < 0) || (socketd >= NSOCKETS) ||
        (socket_list[socketd] == NU_NULL))
        return(NU_INVALID_SOCKET);

    /* Make sure that ODH for recv is enabled. */
    if (!(socket_list[socketd]->odh_flag & NU_ODH_RECEIVE))
        return (NU_ODH_DISABLED);

    /*  Don't let anyone else in until we are through.  */
#ifdef PLUS
    NU_Obtain_Semaphore(&TCP_Resource, NU_SUSPEND);
#else
    NU_Request_Resource(TCP_Resource, NU_WAIT_FOREVER);
#endif
      
    /* Calculate the starting address of the buffer. */
    buf_ptr = (struct pqueue HUGE *)(buffer - sizeof(DLAYER)
                                            - sizeof(IPLAYER)
                                            - sizeof(TCPLAYER)
                                            - PQ_HEADER_SIZE);

    /*  Search the linked list until item is found or the end of the list
     *  is reached. */
    for(item = odh_list.head; ( (item) && (item != buf_ptr) );
        item = item->next)
    ;

    /* If the item was not found then return an error status. */
    if (!item) {
         return_status = NU_INVALID_BUF_PTR;
    }
    /* The item was found, so move it from the ODH list to the
       buffer_freelist. */
    else
    {
         dll_remove((tqe_t *)&odh_list, (tqe_t *)buf_ptr);
         dll_enqueue((tqe_t *)&buffer_freelist, (tqe_t *)buf_ptr);
         return_status = NU_SUCCESS;
    }

#ifdef PLUS
    NU_Release_Semaphore(&TCP_Resource);
#else
    NU_Release_Resource(TCP_Resource);
#endif

    return(return_status);

}  /* end NU_Deallocate_Buffer */

/****************************************************************************/
/* FUNCTION                                                                 */
/*                                                                          */
/*  NU_ODH_Recv                                                             */
/*                                                                          */
/* DESCRIPTION                                                              */
/*                                                                          */
/*  This fuction is responsible for recving data when ODH is being used.    */
/*                                                                          */
/* AUTHOR                                                                   */
/*                                                                          */
/*  Glen Johnson, Accelerated Technology Inc.                               */
/*                                                                          */
/*  CALLED FROM                                                             */
/*                                                                          */
/*      User Applications                                                   */
/*                                                                          */
/* CALLS                                                                    */
/*                                                                          */
/*      NU_Recv                                                             */
/*                                                                          */
/* INPUTS                                                                   */
/*                                                                          */
/*  No inputs to the function                                               */
/*                                                                          */
/* OUTPUTS                                                                  */
/*                                                                          */
/*  No outputs from this function                                           */
/*                                                                          */
/* HISTORY                                                                  */
/*                                                                          */
/*  NAME                   DATE        REMARKS                              */
/*                                                                          */
/*  Glen Johnson         03/13/95    Initial version.                       */
/*                                                                          */
/****************************************************************************/
int16 NU_ODH_Recv (int16 socketd, char **buff, int16 flags)
{
    int32 addr;
    int16 bytes_returned;
    int16 nbytes = 1;


    /*  Validate the socket number.  */
    if ((socketd < 0) || (socketd >= NSOCKETS) ||
        (socket_list[socketd] == NU_NULL))
        return(NU_INVALID_SOCKET);

    /* Make sure that ODH for recv is enabled. */
    if (!(socket_list[socketd]->odh_flag & NU_ODH_RECEIVE))
        return(NU_ODH_DISABLED);

    /* Get the pointer to a buffer. */
    bytes_returned = NU_Recv (socketd, (char *)&addr, nbytes, flags);

    /* Convert the int32 to a memory address. */
    *buff = (char *)addr;

    /* return the number of bytes in the buffer. */
    return(bytes_returned);

} /* end NU_ODH_Recv */

/******************************************************************************/
/* FUNCTION                                                                   */
/*                                                                            */
/*  ODH_Init                                                                  */
/*                                                                            */
/* DESCRIPTION                                                                */
/*                                                                            */
/*  Performs initialization required by the ODH module.                       */
/*                                                                            */
/* AUTHOR                                                                     */
/*                                                                            */
/*  Glen Johnson, Accelerated Technology Inc.                                 */
/*                                                                            */
/*  CALLED FROM                                                               */
/*                                                                            */
/*      protinit                                                              */
/*                                                                            */
/* CALLS                                                                      */
/*                                                                            */
/*      none                                                                  */
/*                                                                            */
/* INPUTS                                                                     */
/*                                                                            */
/*  No inputs to the function                                                 */
/*                                                                            */
/* OUTPUTS                                                                    */
/*                                                                            */
/*  No outputs from this function                                             */
/*                                                                            */
/* HISTORY                                                                    */
/*                                                                            */
/*  NAME                   DATE        REMARKS                                */
/*                                                                            */
/*  Glen Johnson         09/26/96    Initial version.                         */
/*                                                                            */
/******************************************************************************/
STATUS ODH_Init(VOID)
{
    odh_list.head = odh_list.tail = NU_NULL;

    return (NU_SUCCESS);
}