fifo_policy.c

最新rtlinux内核源码

/*********************************************************************************/
/* This file has been written by Sergio Perez Alca駃z <[e-mail]>    */
/*            Departamento de Inform醫ica de Sistemas y Computadores             */
/*            Universidad Polit閏nica de Valencia                                */
/*            Valencia (Spain)                                                   */
/*                                                                               */
/* The RTL-lwIP project has been supported by the Spanish Government Research    */
/* Office (CICYT) under grant TIC2002-04123-C03-03                               */
/*                                                                               */
/* Copyright (c) March, 2003 SISTEMAS DE TIEMPO REAL EMPOTRADOS, FIABLES Y       */
/* DISTRIBUIDOS BASADOS EN COMPONENTES                                           */
/*                                                                               */
/*  This program is free software; you can redistribute it and/or modify         */
/*  it under the terms of the GNU General Public License as published by         */
/*  the Free Software Foundation; either version 2 of the License, or            */
/*  (at your option) any later version.                                          */
/*                                                                               */
/*  This program is distributed in the hope that it will be useful,              */
/*  but WITHOUT ANY WARRANTY; without even the implied warrabnty of              */
/*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                */
/*  GNU General Public License for more details.                                 */
/*                                                                               */
/*  You should have received a copy of the GNU General Public License            */
/*  along with this program; if not, write to the Free Software                  */
/*  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA    */
/*                                                                               */
/*  Linking RTL-lwIP statically or dynamically with other modules is making a    */
/*  combined work based on RTL-lwIP.  Thus, the terms and conditions of the GNU  */
/*  General Public License cover the whole combination.                          */
/*                                                                               */
/*  As a special exception, the copyright holders of RTL-lwIP give you           */
/*  permission to link RTL-lwIP with independent modules that communicate with   */
/*  RTL-lwIP solely through the interfaces, regardless of the license terms of   */
/*  these independent modules, and to copy and distribute the resulting combined */
/*  work under terms of your choice, provided that every copy of the combined    */
/*  work is accompanied by a complete copy of the source code of RTL-lwIP (the   */
/*  version of RTL-lwIP used to produce the combined work), being distributed    */
/*  under the terms of the GNU General Public License plus this exception.  An   */
/*  independent module is a module which is not derived from or based on         */
/*  RTL-lwIP.                                                                    */
/*                                                                               */
/*  Note that people who make modified versions of RTL-lwIP are not obligated to */
/*  grant this special exception for their modified versions; it is their choice */
/*  whether to do so.  The GNU General Public License gives permission to        */
/*  release a modified version without this exception; this exception also makes */
/*  it possible to release a modified version which carries forward this         */
/*  exception.                                                                   */
/*********************************************************************************/

#include "netif/net_policy/FIFO_policy.h"
#include <rtl_malloc.h>
#include "memcopy.h"

/*************************************************************************************/
void FIFO_initialize_rx_buffer(void *rx_buffer){
  struct fifo_rx_buffer_t *fifo_rx_buffer = (struct fifo_rx_buffer_t *) rx_buffer;
  struct fifo_rx_slot_t *tmp;
  int i;
  tmp = fifo_rx_buffer->first = fifo_rx_buffer->add = fifo_rx_buffer->extract = rtl_malloc(sizeof(struct fifo_rx_slot_t));

  for(i=0;i<(MAX_FIFO_RX_BUFFER_ENTRIES-1); i++){ 
    tmp->next = rtl_malloc(sizeof(struct fifo_rx_slot_t));
    tmp->read = 0x01;
    tmp->length = 0;
    tmp->data =  rtl_malloc(PKT_BUF_SZ);
    tmp = tmp->next;
  }
  tmp->next = fifo_rx_buffer->first;
  tmp->read = 0x01;
  tmp->data = rtl_malloc(PKT_BUF_SZ);

  return;
}

/*************************************************************************************/
void FIFO_dealloc_rx_buffer(void *rx_buffer){
  struct fifo_rx_buffer_t *fifo_rx_buffer = (struct fifo_rx_buffer_t *) rx_buffer;
  struct fifo_rx_slot_t *tmp = fifo_rx_buffer->first->next, *actual;
  int i;

  for(i=0;i<(MAX_FIFO_RX_BUFFER_ENTRIES-1); i++){
    actual = tmp->next;
    if(tmp->data != NULL)
      rtl_free(tmp->data);
    rtl_free(tmp);
    tmp = actual;
  }  
  if(fifo_rx_buffer->first->data != NULL)
    rtl_free(fifo_rx_buffer->first->data);
  rtl_free(fifo_rx_buffer->first);

  return;
}

/*************************************************************************************/
int FIFO_add_frame_to_buffer(void *rx_buffer, unsigned char *data, int len){
  struct fifo_rx_buffer_t *fifo_rx_buffer = (struct fifo_rx_buffer_t *) rx_buffer;
  
  /* If the packet in the position that we're writting hasn't still been read is */
  /* because we're receiving too much packets, so we need to drop it.            */ 


  if(fifo_rx_buffer->add->read !=  0x00){
    fifo_rx_buffer->add->length = len;
    
    memcpy(fifo_rx_buffer->add->data,data, len);
    
    fifo_rx_buffer->add->read = 0x00;
    fifo_rx_buffer->add = fifo_rx_buffer->add->next;
    
    return 0;
  }else
    // The packet is dropped  
    return -1;
}

/*************************************************************************************/
int FIFO_extract_frame_of_buffer(void *rx_buffer, void *data){
  struct fifo_rx_buffer_t *fifo_rx_buffer = (struct fifo_rx_buffer_t *) rx_buffer;
  struct fifo_rx_slot_t *tmp = fifo_rx_buffer->extract;

  ((struct memory *)data)->mem = tmp->data;
  tmp->read = 0x01;
  fifo_rx_buffer->extract = fifo_rx_buffer->extract->next;
  
  return tmp->length;
}