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
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。
delete.py
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)
（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)
-
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
# ryu_timeout.py import requests if __name__ == "__main__": url = 'http://127.0.0.1:8080/stats/flowentry/add' with open("./ryu_timeOut.json") as file: str = file.read() headers = {'Content-Type': 'application/json'} res = requests.post(url, str, headers=headers) print (res.content)ryu_timeOut.json
1 # ryu_timeout.json 2 { 3 "dpid": 1, 4 "cookie": 1, 5 "cookie_mask": 1, 6 "table_id": 0, 7 "hard_timeout": 20, 8 "priority": 65535, 9 "flags": 1, 10 "match":{ 11 "in_port":1 12 }, 13 "actions":[ 14 ] 15 16 }
（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_ID | Hosts |
|---|---|
| 0 | h1 h3 |
| 1 | h2 h4 |
topo.py
1 #!/usr/bin/env python
2 from mininet.topo import Topo
3
4 class MyTopo(Topo):
5 def __init__(self):
6 # initilaize topology
7 Topo.__init__(self)
8
9 self.addSwitch("s1")
10 self.addSwitch("s2")
11
12 self.addHost("h1")
13 self.addHost("h2")
14 self.addHost("h3")
15 self.addHost("h4")
16
17 self.addLink("s1", "h1")
18 self.addLink("s1", "h2")
19 self.addLink("s2", "h3")
20 self.addLink("s2", "h4")
21 self.addLink("s1", "s2")
22
23 topos = {'mytopo': (lambda: MyTopo())}
（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）实验报告
这次的实验对我来说难度还是比较大的，主要是代码的编写，通过编写代码来实现网络的超时功能，对于我来说还是有很大的挑战。也是在查阅资料和请教同学的情况下才完成了这次实验。
标签：__,url,self,flow,REST,API,requests,SDN,id From： https://www.cnblogs.com/zwf6698/p/16852593.html