欢迎使用CSDN-markdown编辑器Floodlight模块编写——初涉江湖

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我是靠谱客的博主等待咖啡，最近开发中收集的这篇文章主要介绍欢迎使用CSDN-markdown编辑器Floodlight模块编写——初涉江湖，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

Floodlight模块编写——初涉江湖

准备

完成环境配置安装的准备工作，我安装的是最新版的floodlight，配合mininet虚拟环境进行实验

在Eclipse里添加类

1）右键“src/main/java”新建类
2）包名取作“net.floodlightcontroller.mactracker”,类名：“MACTracker”
3)接口选项“Add…”,添加“IOFloodlightModule”、“IOFMessageListener”
4)“finish”创建完成

生成的类包含以下初始代码：

package net.floodlightcontroller.mactracker;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
import org.projectfloodlight.openflow.protocol.OFMessage;
import org.projectfloodlight.openflow.protocol.OFType;
import org.slf4j.Logger;
import net.floodlightcontroller.core.FloodlightContext;
import net.floodlightcontroller.core.IFloodlightProviderService;
import net.floodlightcontroller.core.IOFMessageListener;
import net.floodlightcontroller.core.IOFSwitch;
import net.floodlightcontroller.core.module.FloodlightModuleContext;
import net.floodlightcontroller.core.module.FloodlightModuleException;
import net.floodlightcontroller.core.module.IFloodlightModule;
import net.floodlightcontroller.core.module.IFloodlightService;
public class MACTracker implements IFloodlightModule, IOFMessageListener {
@Override
public String getName() {
// TODO Auto-generated method stub
return null;
}
@Override
public boolean isCallbackOrderingPrereq(OFType type, String name) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean isCallbackOrderingPostreq(OFType type, String name) {
// TODO Auto-generated method stub
return false;
}
@Override
public net.floodlightcontroller.core.IListener.Command receive(IOFSwitch sw, OFMessage msg,
FloodlightContext cntx) {
// TODO Auto-generated method stub
return null;
}
@Override
public Collection<Class<? extends IFloodlightService>> getModuleServices() {
// TODO Auto-generated method stub
return null;
}
@Override
public Map<Class<? extends IFloodlightService>, IFloodlightService> getServiceImpls() {
// TODO Auto-generated method stub
return null;
}
@Override
public Collection<Class<? extends IFloodlightService>> getModuleDependencies() {
// TODO Auto-generated method stub
return null;
}
@Override
public void init(FloodlightModuleContext context) throws FloodlightModuleException {
// TODO Auto-generated method stub
}
@Override
public void startUp(FloodlightModuleContext context) throws FloodlightModuleException {
// TODO Auto-generated method stub
}
}

具体实现模块

模块依赖的建立

由于需要获取OpenFlow消息，必须获取FloodlightProvider模块的服务，下面这个方法用于建立和其他模块的依赖，建立依赖的模块类类型都存储于L这个数组中，从而调用这些模块的功能

protected IFloodlightProviderService floodlightProvider;
...
@Override
public Collection<Class<? extends IFloodlightService>> getModuleDependencies() {
Collection<Class<? extends IFloodlightService>> l =
new ArrayList<Class<? extends IFloodlightService>>();
l.add(IFloodlightProviderService.class);
return l;
}

还需要一个集合set来存储获取到的MAC地址

protected Set<Long> macAddresses;

模块初始化

初始化函数作用是加载依赖关系，并初始化相关数据结构


@Override
public void init(FloodlightModuleContext context) throws FloodlightModuleException {
floodlightProvider = context.getServiceImpl(IFloodlightProviderService.class);
macAddresses = new ConcurrentSkipListSet<Long>();
logger = LoggerFactory.getLogger(MACTracker.class);
}

处理Packet-In消息

首先在startUp（）方法里注册Packet-In消息

@Override
public void startUp(FloodlightModuleContext context) {
floodlightProvider.addOFMessageListener(OFType.PACKET_IN, this);
}

解析来定义当收到该消息时需要做的操作，获取消息的以太网帧类，由Ethrnet类的接口方法得到源MAC地址，完成简单的注册。
这里注意continue表示在这个模块处理完该消息后还允许其他模块继续处理它

@Override
public net.floodlightcontroller.core.IListener.Command receive(IOFSwitch sw, OFMessage msg, FloodlightContext cntx) {
Ethernet eth =
IFloodlightProviderService.bcStore.get(cntx,
IFloodlightProviderService.CONTEXT_PI_PAYLOAD);
Long sourceMACHash = eth.getSourceMACAddress().getLong();
if (!macAddresses.contains(sourceMACHash)) {
macAddresses.add(sourceMACHash);
logger.info("MAC Address: {} seen on switch: {}",
eth.getSourceMACAddress().toString(),
sw.getId().toString());
}
return Command.CONTINUE;
}

想要解析更多的包内数据，可以查看Packet-In handle

关于各模块处理消息顺序问题

交换机发往控制器的消息，同一时间段只能被一个模块所处理。那么这里就有一个先后顺序的问题
isCallbackOrderingPrereq() defines modules that should run before our module when processing a particular type of OpenFlow message.
isCallbackOrderingPostreq() defines modules that should run after our module when processing a particular type of OpenFlow message.
一个最常见的情况是，当我们用自己的算法去自定义了一种流下发策略，那么必须将Forwording模块设置为在自己模块之后，用第二个方法。
而floodlight已实现的模块中也有例可循，如Forwarding模块在计算路径时需要调用设备管理模块的接口，来获取主机的位置，因此DeviceManager模块必须在Forwarding模块之前处理消息

@Override
public boolean isCallbackOrderingPrereq(OFType type, String name) {
return (type.equals(OFType.PACKET_IN) && (name.equals("topology") || name.equals("devicemanager")));
}

添加模块配置文件

第一个文件注册这个模块是存在的，配置文件：src/main/resources/META-INF/services/net.floodlightcontroller.core.module.IFloodlightModule
直接添加：net.floodlightcontroller.mactracker.MACTracker
第二个文件注册这个模块默认被加载，配置文件：src/main/resources/floodlightdefault.properties
按格式添加：net.floodlightcontroller.mactracker.MACTracker