实验7：基于REST API的SDN北向应用实践

一、实验目的

能够编写程序调用OpenDaylight REST API实现特定网络功能；
能够编写程序调用Ryu REST API实现特定网络功能。

二、实验环境

下载虚拟机软件Oracle VisualBox或VMware；
在虚拟机中安装Ubuntu 20.04 Desktop amd64，并完整安装Mininet、OpenDaylight（Carbon版本）、Postman和Ryu；

三、实验要求

（一）基本要求

OpenDaylight
（1）利用Mininet平台搭建下图所示网络拓扑，并连接OpenDaylight；

sudo mn --topo=single,3 --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13

（2）编写Python程序，调用OpenDaylight的北向接口下发指令删除s1上的流表数据。

import requests
from requests.auth import HTTPBasicAuth

if __name__ == "__main__":
  url = 'http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/'
  headers = {'Content-Type': 'application/json'}
  res = requests.delete(url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
  print (res.content)

（3）编写Python程序，调用OpenDaylight的北向接口下发硬超时流表，实现拓扑内主机h1和h3网络中断20s。

import requests
from requests.auth import HTTPBasicAuth

if __name__ == "__main__":
  url = 'http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/flow-node-inventory:table/0/flow/1'
  with open("./flowtable.json") as f:
      jstr = f.read()
  headers = {'Content-Type': 'application/json'}
  res = requests.put(url, jstr, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
  print (res.content)

json文件:

"flow": [
  {
    "id": "1",
    "match": {
      "in-port": "1",
      "ethernet-match": {
        "ethernet-type": {
          "type": "0x0800"
        }
      },
      "ipv4-destination": "10.0.0.3/32"
    },
    "instructions": {
      "instruction": [
        {
          "order": "0",
          "apply-actions": {
            "action": [
              {
                "order": "0",
                "drop-action": {}
              }
            ]
          }
        }
      ]
    },
    "flow-name": "flow1",
    "priority": "65535",
    "hard-timeout": "20",
    "cookie": "2",
    "table_id": "0"
  }
]
}

（4）编写Python程序，调用OpenDaylight的北向接口获取s1上活动的流表数。

import requests
from requests.auth import HTTPBasicAuth

if __name__ == "__main__":
  url = 'http://127.0.0.1:8181/restconf/operational/opendaylight-inventory:nodes/node/openflow:1/flow-node-inventory:table/0/opendaylight-flow-table-statistics:flow-table-statistics'
  headers = {'Content-Type': 'application/json'}
  res = requests.get(url,headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
  print (res.content)

2. Ryu
（1）编写Python程序，调用Ryu的北向接口，实现上述OpenDaylight实验拓扑上相同的硬超时流表下发。
ryu-manager ryu.app.simple_switch_13 ryu.app.ofctl_rest

import requests

if __name__ == "__main__":
  url = 'http://127.0.0.1:8080/stats/flowentry/add'
  with open("./flowtable.json") as f:
      jstr = f.read()
  headers = {'Content-Type': 'application/json'}
  res = requests.post(url, jstr, headers=headers)
  print (res.content)

（2）利用Mininet平台搭建下图所示网络拓扑，要求支持OpenFlow 1.3协议，主机名、交换机名以及端口对应正确。拓扑生成后需连接Ryu，且Ryu应能够提供REST API服务。

sudo sudo mn --custom myTopo.py --topo mytopo --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13

from mininet.topo import Topo

class MyTopo(Topo):
  def __init__(self):
      # initilaize topology
      Topo.__init__(self)

      self.addSwitch("s1")
      self.addSwitch("s2")

      self.addHost("h1")
      self.addHost("h2")
      self.addHost("h3")
      self.addHost("h4")

      self.addLink("s1", "h1")
      self.addLink("s1", "h2")
      self.addLink("s2", "h3")
      self.addLink("s2", "h4")
      self.addLink("s1", "s2")

topos = {'mytopo': (lambda: MyTopo())}

（3）整理一个Shell脚本，参考Ryu REST API的文档，利用curl命令，实现和实验2相同的VLAN命令行运行

VLAN_ID	Hosts
0	h1 h3
1	h2 h4
shell脚本:

curl -X POST -d '{
  "dpid": 1,
  "priority": 1,
  "match":{
      "in_port": 1
  },
  "actions":[
      {
          "type": "PUSH_VLAN",     
          "ethertype": 33024       
      },
      {
          "type": "SET_FIELD",
          "field": "vlan_vid",    
          "value": 4096            
      },
      {
          "type": "OUTPUT",
          "port": 3
      }
  ]
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '{
  "dpid": 1,
  "priority": 1,
  "match":{
      "in_port": 2
  },
  "actions":[
      {
          "type": "PUSH_VLAN",    
          "ethertype": 33024      
      },
      {
          "type": "SET_FIELD",
          "field": "vlan_vid",     
          "value": 4097           
      },
      {
          "type": "OUTPUT",
          "port": 3
      }
  ]
}' http://localhost:8080/stats/flowentry/add

# 将主机3，4发送来的数据包取出vlan标记
curl -X POST -d '{
  "dpid": 1,
  "priority": 1,
  "match":{
      "vlan_vid": 0
  },
  "actions":[
      {
          "type": "POP_VLAN",    
          "ethertype": 33024       
      },
      {
          "type": "OUTPUT",
          "port": 1
      }
  ]
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '{
  "dpid": 1,
  "priority": 1,
  "match":{
      "vlan_vid": 1
  },
  "actions":[
      {
          "type": "POP_VLAN",    
          "ethertype": 33024      
      },
      {
          "type": "OUTPUT",
          "port": 2
      }
  ]
}' http://localhost:8080/stats/flowentry/add

# 将主机3，4发送来的数据包打上vlan标记
curl -X POST -d '{
  "dpid": 2,
  "priority": 1,
  "match":{
      "in_port": 1
  },
  "actions":[
      {
          "type": "PUSH_VLAN",    
          "ethertype": 33024      
      },
      {
          "type": "SET_FIELD",
          "field": "vlan_vid",    
          "value": 4096          
      },
      {
          "type": "OUTPUT",
          "port": 3
      }
  ]
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '{
  "dpid": 2,
  "priority": 1,
  "match":{
      "in_port": 2
  },
  "actions":[
      {
          "type": "PUSH_VLAN",    
          "ethertype": 33024      
      },
      {
          "type": "SET_FIELD",
          "field": "vlan_vid",   
          "value": 4097           
      },
      {
          "type": "OUTPUT",
          "port": 3
      }
  ]
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '{
  "dpid": 2,
  "priority": 1,
  "match":{
      "vlan_vid": 0
  },
  "actions":[
      {
          "type": "POP_VLAN",    
          "ethertype": 33024      
      },
      {
          "type": "OUTPUT",
          "port": 1
      }
  ]
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '{
  "dpid": 2,
  "priority": 1,
  "match":{
      "vlan_vid": 1
  },
  "actions":[
      {
          "type": "POP_VLAN",    
          "ethertype": 33024      
      },
      {
          "type": "OUTPUT",
          "port": 2
      }
  ]
}' http://localhost:8080/stats/flowentry/add

（二）进阶要求

编程实现基本要求第2部分Ryu（3）中的VLAN划分。

import json

import requests

if __name__ == "__main__":
  url = 'http://127.0.0.1:8080/stats/flowentry/add'
  headers = {'Content-Type': 'application/json'}
  flow1 = {
      "dpid": 1,
      "priority": 1,
      "match":{
          "in_port": 1
      },
      "actions":[
          {
              "type": "PUSH_VLAN",    
              "ethertype": 33024      
          },
          {
              "type": "SET_FIELD",
              "field": "vlan_vid",    
              "value": 4096           
          },
          {
              "type": "OUTPUT",
              "port": 3
          }
      ]
  }
  flow2 = {
      "dpid": 1,
      "priority": 1,
      "match":{
          "in_port": 2
      },
      "actions":[
          {
              "type": "PUSH_VLAN",     
              "ethertype": 33024      
          },
          {
              "type": "SET_FIELD",
              "field": "vlan_vid",     
              "value": 4097           
          },
          {
              "type": "OUTPUT",
              "port": 3
          }
      ]
  }
  flow3 = {
      "dpid": 1,
      "priority": 1,
      "match":{
          "vlan_vid": 0
      },
      "actions":[
          {
              "type": "POP_VLAN",    
              "ethertype": 33024     
          },
          {
              "type": "OUTPUT",
              "port": 1
          }
      ]
  }
  flow4 = {
      "dpid": 1,
      "priority": 1,
      "match": {
          "vlan_vid": 1
      },
      "actions": [
          {
              "type": "POP_VLAN", 
              "ethertype": 33024  
          },
          {
              "type": "OUTPUT",
              "port": 2
          }
      ]
  }
  flow5 = {
      "dpid": 2,
      "priority": 1,
      "match": {
          "in_port": 1
      },
      "actions": [
          {
              "type": "PUSH_VLAN", 
              "ethertype": 33024 
          },
          {
              "type": "SET_FIELD",
              "field": "vlan_vid", 
              "value": 4096  
          },
          {
              "type": "OUTPUT",
              "port": 3
          }
      ]
  }
  flow6 = {
      "dpid": 2,
      "priority": 1,
      "match": {
          "in_port": 2
      },
      "actions": [
          {
              "type": "PUSH_VLAN",  
              "ethertype": 33024  
          },
          {
              "type": "SET_FIELD",
              "field": "vlan_vid",  
              "value": 4097 
          },
          {
              "type": "OUTPUT",
              "port": 3
          }
      ]
  }
  flow7 = {
      "dpid": 2,
      "priority": 1,
      "match": {
          "vlan_vid": 0
      },
      "actions": [
          {
              "type": "POP_VLAN", 
              "ethertype": 33024  
          },
          {
              "type": "OUTPUT",
              "port": 1
          }
      ]
  }
  flow8 = {
      "dpid": 2,
      "priority": 1,
      "match": {
          "vlan_vid": 1
      },
      "actions": [
          {
              "type": "POP_VLAN", 
              "ethertype": 33024  
          },
          {
              "type": "OUTPUT",
              "port": 2
          }
      ]
  }
  res1 = requests.post(url, json.dumps(flow1), headers=headers)
  res2 = requests.post(url, json.dumps(flow2), headers=headers)
  res3 = requests.post(url, json.dumps(flow3), headers=headers)
  res4 = requests.post(url, json.dumps(flow4), headers=headers)
  res5 = requests.post(url, json.dumps(flow5), headers=headers)
  res6 = requests.post(url, json.dumps(flow6), headers=headers)
  res7 = requests.post(url, json.dumps(flow7), headers=headers)
  res8 = requests.post(url, json.dumps(flow8), headers=headers)

四、个人总结

实验难度：难，需要写很多代码，还有新的工具和命令
遇到的问题：
- 做完一个部分以后没有及时地清除流表导致最后的实验结果与预期结果不同
- 在做Ryu时没有退出ODL导致端口被占用报错
- 运行脚本文件时curl未安装
个人感想：
在这次的实验过程中学会了编写python代码来调用API，使用OpenDaylight和Ryu的REST API实现特定网络功能，了解了安装并且使用curl的命令，巩固了关于这两个控制器的使用方式并且对于这两个控制器的API使用有了新的认识。实验中遇到了像没有清空流表导致实验结果与预期不符合的问题，最后通过询问同学解决。这次实验的主要难度还是在于文档资料的阅读还有代码的编写，而自己在这方面的能力有所欠缺因此这次实验做的时间很长不是很顺，感觉自己在阅读文档找资料还有编程方面还需要加强

posted @ 2021-10-26 19:31 ZbShi 阅读(22) 评论(0) 编辑收藏举报

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