一、实验目的
1、能够独立部署RYU控制器;
2、能够理解RYU控制器实现软件定义的集线器原理;
3、能够理解RYU控制器实现软件定义的交换机原理。
二、实验环境
Ubuntu 20.04 Desktop amd64
三、实验要求
(一)基本要求
1、搭建下图所示SDN拓扑,协议使用Open Flow 1.0,并连接Ryu控制器,通过Ryu的图形界面查看网络拓扑。
构建topo
sudo mn --topo=single,3 --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow10
连接ryu控制器
ryu-manager ../ryu/ryu/app/gui_topology/gui_topology.py --observe-links
通过Ryu的图形界面查看网络拓扑,在浏览器中输入127.0.0.1:8080
2、阅读Ryu文档的The First Application一节,运行当中的L2Switch,h1 ping h2或h3,在目标主机使用 tcpdump 验证L2Switch,分析L2Switch和POX的Hub模块有何不同。
- 编写L2Switch.py
-
from ryu.base import app_manager from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER from ryu.controller.handler import set_ev_cls from ryu.ofproto import ofproto_v1_0 class L2Switch(app_manager.RyuApp): OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION] def __init__(self, *args, **kwargs): super(L2Switch, self).__init__(*args, **kwargs) @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER) def packet_in_handler(self, ev): msg = ev.msg dp = msg.datapath ofp = dp.ofproto ofp_parser = dp.ofproto_parser actions = [ofp_parser.OFPActionOutput(ofp.OFPP_FLOOD)] data = None if msg.buffer_id == ofp.OFP_NO_BUFFER: data = msg.data out = ofp_parser.OFPPacketOut( datapath=dp, buffer_id=msg.buffer_id, in_port=msg.in_port, actions=actions, data = data) dp.send_msg(out)
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运行L2Switch.py
重新构建拓扑,并对h2、h3节点进行抓包
h1 ping h2
h1 ping h3
查看流表
pox下查看拓扑流表
对比可得,ryu下查不到流表,而在pox下可查看流表!
3、编程修改L2Switch.py,另存为L2xxxxxxxxx.py,使之和POX的Hub模块的变得一致?(xxxxxxxxx为学号)
- L2_212006236.py
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from ryu.base import app_manager from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER from ryu.controller.handler import set_ev_cls from ryu.ofproto import ofproto_v1_3 class L2Switch(app_manager.RyuApp): OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self, *args, **kwargs): super(L2Switch, self).__init__(*args, **kwargs) @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER) def switch_features_handler(self, ev): datapath = ev.msg.datapath ofproto = datapath.ofproto parser = datapath.ofproto_parser # install table-miss flow entry # # We specify NO BUFFER to max_len of the output action due to # OVS bug. At this moment, if we specify a lesser number, e.g., # 128, OVS will send Packet-In with invalid buffer_id and # truncated packet data. In that case, we cannot output packets # correctly. The bug has been fixed in OVS v2.1.0. match = parser.OFPMatch() actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER, ofproto.OFPCML_NO_BUFFER)] self.add_flow(datapath, 0, match, actions) def add_flow(self, datapath, priority, match, actions, buffer_id=None): ofproto = datapath.ofproto parser = datapath.ofproto_parser inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS, actions)] if buffer_id: mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id, priority=priority, match=match, instructions=inst) else: mod = parser.OFPFlowMod(datapath=datapath, priority=priority, match=match, instructions=inst) datapath.send_msg(mod) @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER) def packet_in_handler(self, ev): msg = ev.msg dp = msg.datapath ofp = dp.ofproto ofp_parser = dp.ofproto_parser in_port = msg.match['in_port'] actions = [ofp_parser.OFPActionOutput(ofp.OFPP_FLOOD)] data = None if msg.buffer_id == ofp.OFP_NO_BUFFER: data = msg.data out = ofp_parser.OFPPacketOut( datapath=dp, buffer_id=msg.buffer_id, in_port=in_port, actions=actions, data = data) dp.send_msg(out)
运行L2_212006158.py
-
ryu-manager L2_212006158.py
创建topo
-
sudo mn --topo=single,3 --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13
测试
-
pingall
查看流表
-
dpctl dump-flows
![](/i/l/?n=22&i=blog/2980642/202211/2980642-20221106164914121-1838711087.png)
(二)进阶要求
1、阅读Ryu关于simple_switch.py和simple_switch_1x.py的实现,以simple_switch_13.py为例,完成其代码的注释工作,并回答下列问题:
simple_switch_13.py分析
# Copyright (C) 2011 Nippon Telegraph and Telephone Corporation. # # Licensed 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. # 引入包 from ryu.base import app_manager from ryu.controller import ofp_event from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER from ryu.controller.handler import set_ev_cls from ryu.ofproto import ofproto_v1_3 from ryu.lib.packet import packet from ryu.lib.packet import ethernet from ryu.lib.packet import ether_types class SimpleSwitch13(app_manager.RyuApp): # 指定OpenFlow版本为1.3 OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self, *args, **kwargs): super(SimpleSwitch13, self).__init__(*args, **kwargs) self.mac_to_port = {} # 一个保存(交换机id, mac地址)到转发端口的字典 # 处理EventOFPSwitchFeatures事件 @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER) def switch_features_handler(self, ev): datapath = ev.msg.datapath ofproto = datapath.ofproto parser = datapath.ofproto_parser # install table-miss flow entry # # We specify NO BUFFER to max_len of the output action due to # OVS bug. At this moment, if we specify a lesser number, e.g., # 128, OVS will send Packet-In with invalid buffer_id and # truncated packet data. In that case, we cannot output packets # correctly. The bug has been fixed in OVS v2.1.0. match = parser.OFPMatch()#match:流表项匹配,OFPMatch():不匹配任何信息 actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER, ofproto.OFPCML_NO_BUFFER)] self.add_flow(datapath, 0, match, actions)#添加流表项 # 添加流表 def add_flow(self, datapath, priority, match, actions, buffer_id=None): # 获取交换机信息 ofproto = datapath.ofproto parser = datapath.ofproto_parser # 包装action inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS, actions)] # 判断是否有buffer_id,生成相应的mod对象 if buffer_id: mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id, priority=priority, match=match, instructions=inst) else: mod = parser.OFPFlowMod(datapath=datapath, priority=priority, match=match, instructions=inst) # 发送mod datapath.send_msg(mod) # 触发packet in事件时,调用_packet_in_handler函数 @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER) def _packet_in_handler(self, ev): # If you hit this you might want to increase # the "miss_send_length" of your switch if ev.msg.msg_len < ev.msg.total_len: self.logger.debug("packet truncated: only %s of %s bytes", ev.msg.msg_len, ev.msg.total_len) # 获取Packet_In报文中的各种信息:包信息,交换机信息,协议等等 msg = ev.msg datapath = msg.datapath ofproto = datapath.ofproto parser = datapath.ofproto_parser in_port = msg.match['in_port'] pkt = packet.Packet(msg.data) eth = pkt.get_protocols(ethernet.ethernet)[0] # 忽略LLDP类型 if eth.ethertype == ether_types.ETH_TYPE_LLDP: # ignore lldp packet return # 获取源端口,目的端口 dst = eth.dst src = eth.src dpid = format(datapath.id, "d").zfill(16) self.mac_to_port.setdefault(dpid, {}) self.logger.info("packet in %s %s %s %s", dpid, src, dst, in_port) # 学习包的源地址,和交换机上的入端口绑定 # learn a mac address to avoid FLOOD next time. self.mac_to_port[dpid][src] = in_port # 在字典中查找目的mac地址是否有对应的出端口 if dst in self.mac_to_port[dpid]: out_port = self.mac_to_port[dpid][dst] # 没有就进行洪泛 else: out_port = ofproto.OFPP_FLOOD actions = [parser.OFPActionOutput(out_port)] # 下发流表处理后续包,不再触发 packet in 事件 # install a flow to avoid packet_in next time if out_port != ofproto.OFPP_FLOOD: match = parser.OFPMatch(in_port=in_port, eth_dst=dst, eth_src=src) # verify if we have a valid buffer_id, if yes avoid to send both # flow_mod & packet_out if msg.buffer_id != ofproto.OFP_NO_BUFFER: self.add_flow(datapath, 1, match, actions, msg.buffer_id) return else: self.add_flow(datapath, 1, match, actions) data = None if msg.buffer_id == ofproto.OFP_NO_BUFFER: data = msg.data # 发送Packet_out数据包 out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id, in_port=in_port, actions=actions, data=data) # 发送流表 datapath.send_msg(out)
a) 代码当中的mac_to_port的作用是什么?
保存mac地址到交换机端口的映射
b) simple_switch和simple_switch_13在dpid的输出上有何不同?
simple_switch.py : dpid = datapath.id
simple_switch 直接输出dpid
simple_switch_13.py:dpid = format(datapath.id, "d").zfill(16)
simple_switch_13将dpid填充0至16位
c) 相比simple_switch,simple_switch_13增加的switch_feature_handler实现了什么功能?
switch_feature_handler的作用是:将缺失流表项添加到流表中,当封包没有匹配到流表项时,就触发packet_in
d) simple_switch_13是如何实现流规则下发的?
在接收到packetin事件后,首先获取包学习,交换机信息,以太网信息,协议信息等。 如果以太网类型是LLDP类型,则不予处理。 如果不是,则获取源端口目的端口,以及交换机id,先学习源地址对应的交换机的入端口,再查看是否已经学习目的mac地址,如果没有则进行洪泛转发。 如果学习过该mac地址,则查看是否有buffer_id,如果有的话,则在添加流动作时加上buffer_id,向交换机发送流表。
e) switch_features_handler和_packet_in_handler两个事件在发送流规则的优先级上有何不同?
switch_features_handler下发流表的优先级更高
2、编程实现和ODL实验的一样的硬超时功能。
通过控制开断L2_212006236.py来实现
-
修改simple_switch_13.py代码实现硬超时功能
# Copyright (C) 2011 Nippon Telegraph and Telephone Corporation. # # Licensed 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. # 引入包 from ryu.base import app_manager from ryu.controller import ofp_event from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER from ryu.controller.handler import set_ev_cls from ryu.ofproto import ofproto_v1_3 from ryu.lib.packet import packet from ryu.lib.packet import ethernet from ryu.lib.packet import ether_types class SimpleSwitch13(app_manager.RyuApp): # 指定OpenFlow版本为1.3 OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self, *args, **kwargs): super(SimpleSwitch13, self).__init__(*args, **kwargs) self.mac_to_port = {} # 一个保存(交换机id, mac地址)到转发端口的字典 # 处理EventOFPSwitchFeatures事件 @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER) def switch_features_handler(self, ev): datapath = ev.msg.datapath ofproto = datapath.ofproto parser = datapath.ofproto_parser # install table-miss flow entry # # We specify NO BUFFER to max_len of the output action due to # OVS bug. At this moment, if we specify a lesser number, e.g., # 128, OVS will send Packet-In with invalid buffer_id and # truncated packet data. In that case, we cannot output packets # correctly. The bug has been fixed in OVS v2.1.0. match = parser.OFPMatch()#match:流表项匹配,OFPMatch():不匹配任何信息 actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER, ofproto.OFPCML_NO_BUFFER)] self.add_flow(datapath, 0, match, actions)#添加流表项 # 添加流表 def add_flow(self, datapath, priority, match, actions, buffer_id=None,hard_timeout=0): # 获取交换机信息 ofproto = datapath.ofproto parser = datapath.ofproto_parser # 包装action inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS, actions)] # 判断是否有buffer_id,生成相应的mod对象 if buffer_id: mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id, priority=priority, match=match, instructions=inst,hard_timeout=hard_timeout) else: mod = parser.OFPFlowMod(datapath=datapath, priority=priority, match=match, instructions=inst,hard_timeout=hard_timeout) # 发送mod datapath.send_msg(mod) # 触发packet in事件时,调用_packet_in_handler函数 @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER) def _packet_in_handler(self, ev): # If you hit this you might want to increase # the "miss_send_length" of your switch if ev.msg.msg_len < ev.msg.total_len: self.logger.debug("packet truncated: only %s of %s bytes", ev.msg.msg_len, ev.msg.total_len) # 获取Packet_In报文中的各种信息:包信息,交换机信息,协议等等 msg = ev.msg datapath = msg.datapath ofproto = datapath.ofproto parser = datapath.ofproto_parser in_port = msg.match['in_port'] pkt = packet.Packet(msg.data) eth = pkt.get_protocols(ethernet.ethernet)[0] # 忽略LLDP类型 if eth.ethertype == ether_types.ETH_TYPE_LLDP: # ignore lldp packet return # 获取源端口,目的端口 dst = eth.dst src = eth.src dpid = format(datapath.id, "d").zfill(16) self.mac_to_port.setdefault(dpid, {}) self.logger.info("packet in %s %s %s %s", dpid, src, dst, in_port) # 学习包的源地址,和交换机上的入端口绑定 # learn a mac address to avoid FLOOD next time. self.mac_to_port[dpid][src] = in_port # 在字典中查找目的mac地址是否有对应的出端口 if dst in self.mac_to_port[dpid]: out_port = self.mac_to_port[dpid][dst] # 没有就进行洪泛 else: out_port = ofproto.OFPP_FLOOD actions = [parser.OFPActionOutput(out_port)] actions_timeout = [] # 下发流表处理后续包,不再触发 packet in 事件 # install a flow to avoid packet_in next time if out_port != ofproto.OFPP_FLOOD: match = parser.OFPMatch(in_port=in_port, eth_dst=dst, eth_src=src) # verify if we have a valid buffer_id, if yes avoid to send both # flow_mod & packet_out if msg.buffer_id != ofproto.OFP_NO_BUFFER: self.add_flow(datapath, 2, match, actions_timeout, msg.buffer_id,hard_timeout=10) self.add_flow(datapath, 1, match, actions, msg.buffer_id) return else: self.add_flow(datapath, 2, match, actions_timeout,hard_timeout=10) self.add_flow(datapath, 1, match, actions) data = None if msg.buffer_id == ofproto.OFP_NO_BUFFER: data = msg.data # 发送Packet_out数据包 out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id, in_port=in_port, actions=actions, data=data) # 发送流表 datapath.send_msg(out)
(三)个人感想
本次实验考验了对ryu的使用以及在ping通期间的一些注意
也依旧考验了对于学生的代码认知能力。
标签:控制器,parser,datapath,port,msg,开源,ofproto,RYU,id From: https://www.cnblogs.com/123456aabbssdd/p/16863059.html