2019 SDN上机第5次作业
1.浏览RYU官网学习RYU控制器的安装和RYU开发入门教程,提交你对于教程代码的理解,包括但不限于:
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描述官方教程实现了一个什么样的交换机功能?
将接收到的数据包发送到所有端口的功能
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控制器设定交换机支持什么版本的OpenFlow?
OpenFlow v1.0
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控制器设定了交换机如何处理数据包?
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): #设置想要向交换机协商的OpenFlow版本号 OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION] #控制器会自动交换Hello包,协商版本号,接着协商完成之后,它再自动执行交换Features包,进行握手 def __init__(self, *args, **kwargs): super(L2Switch, self).__init__(*args, **kwargs) ##握手完成后,使用set_ev_cls函数处理Features响应包 @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER) def packet_in_handler(self, ev):#这里调用处理函数,并解析返回包的字段 msg = ev.msg dp = msg.datapath ofp = dp.ofproto ofp_parser = dp.ofproto_parser actions = [ofp_parser.OFPActionOutput(ofp.OFPP_FLOOD)] out = ofp_parser.OFPPacketOut( datapath=dp, buffer_id=msg.buffer_id, in_port=msg.in_port, actions=actions) dp.send_msg(out)#datapath类的send_msg方法,Ryu生成联机数据格式并将其发送到交换机
2.根据官方教程和提供的示例代码(SimpleSwitch.py),将具有自学习功能的交换机代码(SelfLearning.py)补充完整
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
from ryu.lib.mac import haddr_to_bin
from ryu.lib.packet import packet
from ryu.lib.packet import ethernet
from ryu.lib.packet import ether_types
class SimpleSwitch(app_manager.RyuApp):
# TODO define OpenFlow 1.0 version for the switch
# add your code here
OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION]#
def __init__(self, *args, **kwargs):
super(SimpleSwitch, self).__init__(*args, **kwargs)
self.mac_to_port = {}
def add_flow(self, datapath, in_port, dst, src, actions):
ofproto = datapath.ofproto
match = datapath.ofproto_parser.OFPMatch(
in_port=in_port,
dl_dst=haddr_to_bin(dst), dl_src=haddr_to_bin(src))
mod = datapath.ofproto_parser.OFPFlowMod(
datapath=datapath, match=match, cookie=0,
command=ofproto.OFPFC_ADD, idle_timeout=0, hard_timeout=0,
priority=ofproto.OFP_DEFAULT_PRIORITY,
flags=ofproto.OFPFF_SEND_FLOW_REM, actions=actions)
# TODO send modified message out
# add your code here
datapath.send_msg(mod)#
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
pkt = packet.Packet(msg.data)
eth = pkt.get_protocol(ethernet.ethernet)
if eth.ethertype == ether_types.ETH_TYPE_LLDP:
# ignore lldp packet
return
if eth.ethertype == ether_types.ETH_TYPE_IPV6:
# ignore ipv6 packet
return
dst = eth.dst
src = eth.src
dpid = datapath.id
self.mac_to_port.setdefault(dpid, {})
self.logger.info("packet in DPID:%s MAC_SRC:%s MAC_DST:%s IN_PORT:%s", dpid, src, dst, msg.in_port)
# learn a mac address to avoid FLOOD next time.
self.mac_to_port[dpid][src] = msg.in_port
if dst in self.mac_to_port[dpid]:
out_port = self.mac_to_port[dpid][dst]
else:
out_port = ofproto.OFPP_FLOOD
# TODO define the action for output
# add your code here
actions = [datapath.ofproto_parser.OFPActionOutput(out_port)]
# install a flow to avoid packet_in next time
if out_port != ofproto.OFPP_FLOOD:
self.logger.info("add flow s:DPID:%s Match:[ MAC_SRC:%s MAC_DST:%s IN_PORT:%s ], Action:[OUT_PUT:%s] ", dpid, src, dst, msg.in_port, out_port)
self.add_flow(datapath, msg.in_port, dst, src, actions)
data = None
if msg.buffer_id == ofproto.OFP_NO_BUFFER:
data = msg.data
# TODO define the OpenFlow Packet Out
# add your code here
out = datapath.ofproto_parser.OFPPacketOut(
datapath=datapath,
buffer_id=msg.buffer_id,
in_port=msg.in_port,
actions=actions, data=data)
datapath.send_msg(out)
print ("PACKET_OUT...")
3.在mininet创建一个最简拓扑,并连接RYU控制器
开启具有SelfLearning功能的控制器 并创建拓扑
4.验证自学习交换机的功能,提交分析过程和验证结果
进行h1对h2的ping操作 ,ryu控制器 显示出预期信息
mininet查看流表
5.写下你的实验体会
python代码的缩进要注意,改了很久很久很久。
增加代码的四个地方,头两个简单的通过参考样例代码可以知道,后面的两个它通过参考同学的代码解决了问题。