实验7：基于REST API的SDN北向应用实践

 

一、实验目的

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

二、实验环境

  1. 下载虚拟机软件Oracle VisualBox或VMware；
  2. 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

  1. 编写Python程序，调用OpenDaylight的北向接口实现以下功能
    （1） 利用Mininet平台搭建下图所示网络拓扑，并连接OpenDaylight；

    （2） 下发指令删除s1上的流表数据。

     1 #!/usr/bin/python
 2 import requests
 3 from requests.auth import HTTPBasicAuth
 4 
 5 def http_delete(url):
 6     url= url
 7     headers = {'Content-Type':'application/json'}
 8     resp = requests.delete(url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
 9     return resp
10 
11 if __name__ == "__main__":
12     url = 'http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/'
13     resp = http_delete(url)
14     print(resp.content)

     

  2. （3） 下发硬超时流表，实现拓扑内主机h1和h3网络中断20s。

    timeout.py

     1 # timeout.py
 2 import requests
 3 from requests.auth import HTTPBasicAuth
 4 if __name__ == "__main__":
 5     url = 'http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/flow-node-inventory:table/0/flow/1'
 6     with open("./timeOut.json") as file:
 7         str = file.read()
 8     headers = {'Content-Type': 'application/json'}
 9     res = requests.put(url, str, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
10     print (res.content)

    timeout.json

     1 # timeout.json
 2 {
 3     "flow": [
 4       {
 5         "id": "1",
 6         "match": {
 7           "in-port": "1",
 8           "ethernet-match": {
 9             "ethernet-type": {
10               "type": "0x0800"
11             }
12           },
13           "ipv4-destination": "10.0.0.3/32"
14         },
15         "instructions": {
16           "instruction": [
17             {
18               "order": "0",
19               "apply-actions": {
20                 "action": [
21                   {
22                     "order": "0",
23                     "drop-action": {}
24                   }
25                 ]
26               }
27             }
28           ]
29         },
30         "flow-name": "flow",
31         "priority": "65535",
32         "hard-timeout": "20",
33         "cookie": "2",
34         "table_id": "0"
35       }
36     ]
37   }

     

    （4） 获取s1上活动的流表数。

     

    getflow.py

    1 # getflow.py
2 import requests
3 from requests.auth import HTTPBasicAuth
4 if __name__ == "__main__":
5     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'
6     headers = {'Content-Type': 'application/json'}
7     res = requests.get(url,headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
8     print (res.content)

     

  3. 编写Python程序，调用Ryu的北向接口实现以下功能
    （1） 实现上述OpenDaylight实验拓扑上相同的硬超时流表下发。

    ryu_timeout.py

    1 # ryu_timeout.py
2 import requests
3 if __name__ == "__main__":
4     url = 'http://127.0.0.1:8080/stats/flowentry/add'
5     with open("./ryu_timeOut.json") as file:
6         str = file.read()
7     headers = {'Content-Type': 'application/json'}
8     res = requests.post(url, str, headers=headers)
9     print (res.content)

    ryu_timeout.json

    # ryu_timeout.json
{
    "dpid": 1,
    "cookie": 1,
    "cookie_mask": 1,
    "table_id": 0,
    "hard_timeout": 20,
    "priority": 65535,
    "flags": 1,
    "match":{
        "in_port":1
    },
    "actions":[
]
}

     

    （2） 参考Ryu REST API的文档，基于VLAN实验的网络拓扑，编程实现相同的VLAN配置。
    提示：拓扑生成后需连接Ryu，且Ryu应能够提供REST API服务

VLAN_IDHosts
0 h1 h3
1 h2 h4

拓扑代码ryu_topo.py

# ryu_topo.py
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())}

ryu_vlan.py代码

  1 # ryu_vlan.py
  2 import json
  3 
  4 import requests
  5 
  6 if __name__ == "__main__":
  7     url = 'http://127.0.0.1:8080/stats/flowentry/add'
  8     headers = {'Content-Type': 'application/json'}
  9     flow1 = {
 10         "dpid": 1,
 11         "priority": 1,
 12         "match":{
 13             "in_port": 1
 14         },
 15         "actions":[
 16             {
 17                 "type": "PUSH_VLAN",    
 18                 "ethertype": 33024      
 19             },
 20             {
 21                 "type": "SET_FIELD",
 22                 "field": "vlan_vid",    
 23                 "value": 4096           
 24             },
 25             {
 26                 "type": "OUTPUT",
 27                 "port": 3
 28             }
 29         ]
 30     }
 31     flow2 = {
 32         "dpid": 1,
 33         "priority": 1,
 34         "match":{
 35             "in_port": 2
 36         },
 37         "actions":[
 38             {
 39                 "type": "PUSH_VLAN",     
 40                 "ethertype": 33024      
 41             },
 42             {
 43                 "type": "SET_FIELD",
 44                 "field": "vlan_vid",     
 45                 "value": 4097           
 46             },
 47             {
 48                 "type": "OUTPUT",
 49                 "port": 3
 50             }
 51         ]
 52     }
 53     flow3 = {
 54         "dpid": 1,
 55         "priority": 1,
 56         "match":{
 57             "vlan_vid": 0
 58         },
 59         "actions":[
 60             {
 61                 "type": "POP_VLAN",    
 62                 "ethertype": 33024     
 63             },
 64             {
 65                 "type": "OUTPUT",
 66                 "port": 1
 67             }
 68         ]
 69     }
 70     flow4 = {
 71         "dpid": 1,
 72         "priority": 1,
 73         "match": {
 74             "vlan_vid": 1
 75         },
 76         "actions": [
 77             {
 78                 "type": "POP_VLAN", 
 79                 "ethertype": 33024  
 80             },
 81             {
 82                 "type": "OUTPUT",
 83                 "port": 2
 84             }
 85         ]
 86     }
 87     flow5 = {
 88         "dpid": 2,
 89         "priority": 1,
 90         "match": {
 91             "in_port": 1
 92         },
 93         "actions": [
 94             {
 95                 "type": "PUSH_VLAN", 
 96                 "ethertype": 33024 
 97             },
 98             {
 99                 "type": "SET_FIELD",
100                 "field": "vlan_vid", 
101                 "value": 4096  
102             },
103             {
104                 "type": "OUTPUT",
105                 "port": 3
106             }
107         ]
108     }
109     flow6 = {
110         "dpid": 2,
111         "priority": 1,
112         "match": {
113             "in_port": 2
114         },
115         "actions": [
116             {
117                 "type": "PUSH_VLAN",  
118                 "ethertype": 33024  
119             },
120             {
121                 "type": "SET_FIELD",
122                 "field": "vlan_vid",  
123                 "value": 4097 
124             },
125             {
126                 "type": "OUTPUT",
127                 "port": 3
128             }
129         ]
130     }
131     flow7 = {
132         "dpid": 2,
133         "priority": 1,
134         "match": {
135             "vlan_vid": 0
136         },
137         "actions": [
138             {
139                 "type": "POP_VLAN", 
140                 "ethertype": 33024  
141             },
142             {
143                 "type": "OUTPUT",
144                 "port": 1
145             }
146         ]
147     }
148     flow8 = {
149         "dpid": 2,
150         "priority": 1,
151         "match": {
152             "vlan_vid": 1
153         },
154         "actions": [
155             {
156                 "type": "POP_VLAN", 
157                 "ethertype": 33024  
158             },
159             {
160                 "type": "OUTPUT",
161                 "port": 2
162             }
163         ]
164     }
165     res1 = requests.post(url, json.dumps(flow1), headers=headers)
166     res2 = requests.post(url, json.dumps(flow2), headers=headers)
167     res3 = requests.post(url, json.dumps(flow3), headers=headers)
168     res4 = requests.post(url, json.dumps(flow4), headers=headers)
169     res5 = requests.post(url, json.dumps(flow5), headers=headers)
170     res6 = requests.post(url, json.dumps(flow6), headers=headers)
171     res7 = requests.post(url, json.dumps(flow7), headers=headers)
172     res8 = requests.post(url, json.dumps(flow8), headers=headers)

 

（二）进阶要求

OpenDaylight或Ryu任选其一，编程实现查看前序VLAN实验拓扑中所有节点（含交换机、主机）的名称，以及显示每台交换机的所有流表项。

GetNode.py

 1 import requests
 2 import time
 3 import re
 4 
 5 
 6 class GetNodes:
 7     def __init__(self, ip):
 8         self.ip = ip
 9 
10     def get_switch_id(self):
11         url = 'http://' + self.ip + '/stats/switches'
12         re_switch_id = requests.get(url=url).json()
13         switch_id_hex = []
14         for i in re_switch_id:
15             switch_id_hex.append(hex(i))
16 
17         return switch_id_hex
18 
19     def getflow(self):
20         url = 'http://' + self.ip + '/stats/flow/%d'
21         switch_list = self.get_switch_id()
22         ret_flow = []
23         for switch in switch_list:
24             new_url = format(url % int(switch, 16))
25             re_switch_flow = requests.get(url=new_url).json()
26             ret_flow.append(re_switch_flow)
27         return ret_flow
28 
29     def show(self):
30         flow_list = self.getflow()
31         for flow in flow_list:
32             for dpid in flow.keys():
33                 dp_id = dpid
34                 switchnum= '{1}'.format(hex(int(dp_id)), int(dp_id))
35                 print('s'+switchnum,end = " ")
36                 switchnum = int(switchnum)
37             for list_table in flow.values():
38                 for table in list_table:
39                     string1 = str(table)
40                     if re.search("'dl_vlan': '(.*?)'", string1) is not None:
41                        num = re.search("'dl_vlan': '(.*?)'", string1).group(1);
42                        if num == '0' and switchnum == 1:
43                           print('h1',end = " ")
44                        if num == '1' and switchnum == 1:
45                           print('h2',end = " ")
46                        if num == '0' and switchnum == 2:
47                           print('h3',end = " ")
48                        if num == '1' and switchnum == 2:
49                           print('h4',end = " ")
50         print("")
51         flow_list = self.getflow()
52         for flow in flow_list:
53             for dpid in flow.keys():
54                 dp_id = dpid
55                 print('switch_name:s{1}'.format(hex(int(dp_id)), int(dp_id)))
56             for list_table in flow.values():
57                 for table in list_table:
58                     print(table)
59 s1 = GetNodes("127.0.0.1:8080")
60 s1.show()

（三）个人总结

　　在本次的实验过程中，还是遇到了比较多的问题，第一个是在运行python xxx.py命令的时候会出现requests.exceptions.ProxyError:很长一段报错，百度搜索了很多都没有得到解决，后面发现加上sudo就能够执行了。第二个是本次实验使我能够编写程序调用OpenDaylight REST API、Ryu REST API实现特定网络功能。第二个是在硬超时中断20秒，一直没成功，看了我已经打开的端口发现我的ryu根本没有成功打开，且犯了跟上次实验一样的问题，在运行ryu的时候忘记把ODL关闭了，所以就没有成功打开ryu。个人感觉本次实验难度较大，并且本次实验需要有一定的Python基础，需要通过api来完成各种功能，并且要结合前几次的实验。

posted @ 2022-11-03 10:59  vision0724  阅读(44)  评论(0)    收藏  举报