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
#!/usr/bin/python import requests from requests.auth import HTTPBasicAuth def http_delete(url): url= url headers = {'Content-Type':'application/json'} resp = requests.delete(url, headers=headers, auth=HTTPBasicAuth('admin', 'admin')) return resp if __name__ == "__main__": url = 'http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/' resp = http_delete(url) 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
#!/usr/bin/python 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("./timeout.json") as file: str = file.read() headers = {'Content-Type': 'application/json'} res = requests.put(url, str, headers=headers, auth=HTTPBasicAuth('admin', 'admin')) print (res.content)timeout.json
# timeout.json { "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": "flow", "priority": "65535", "hard-timeout": "20", "cookie": "2", "table_id": "0" } ] }
（4） 获取s1上活动的流表数。
getflow.py
# getflow.py 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)
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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。
timeout_2.py
# timeout_2.py import requests if __name__ == "__main__": url = 'http://127.0.0.1:8080/stats/flowentry/add' with open("./timeout_2.json") as file: str = file.read() headers = {'Content-Type': 'application/json'} res = requests.post(url, str, headers=headers) print (res.content)timeout_2.json
# timeout_2.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#!/usr/bin/env python 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())}
（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。
import requests
import time
import re
class GetNodes:
def __init__(self, ip):
self.ip = ip
def get_switch_id(self):
url = 'http://' + self.ip + '/stats/switches'
re_switch_id = requests.get(url=url).json()
switch_id_hex = []
for i in re_switch_id:
switch_id_hex.append(hex(i))
return switch_id_hex
def getflow(self):
url = 'http://' + self.ip + '/stats/flow/%d'
switch_list = self.get_switch_id()
ret_flow = []
for switch in switch_list:
new_url = format(url % int(switch, 16))
re_switch_flow = requests.get(url=new_url).json()
ret_flow.append(re_switch_flow)
return ret_flow
def show(self):
flow_list = self.getflow()
for flow in flow_list:
for dpid in flow.keys():
dp_id = dpid
switchnum= '{1}'.format(hex(int(dp_id)), int(dp_id))
print('s'+switchnum,end = " ")
switchnum = int(switchnum)
for list_table in flow.values():
for table in list_table:
string1 = str(table)
if re.search("'dl_vlan': '(.*?)'", string1) is not None:
num = re.search("'dl_vlan': '(.*?)'", string1).group(1);
if num == '0' and switchnum == 1:
print('h1',end = " ")
if num == '1' and switchnum == 1:
print('h2',end = " ")
if num == '0' and switchnum == 2:
print('h3',end = " ")
if num == '1' and switchnum == 2:
print('h4',end = " ")
print("")
flow_list = self.getflow()
for flow in flow_list:
for dpid in flow.keys():
dp_id = dpid
print('switch_name:s{1}'.format(hex(int(dp_id)), int(dp_id)))
for list_table in flow.values():
for table in list_table:
print(table)
s1 = GetNodes("127.0.0.1:8080")
s1.show()
（三）个人总结
- 请用Markdown排版；
- 将所有本实验相关文件保存在目录/home/用户名/学号/lab7/中；
- （一）只需要提交实现相应Python代码和执行结果截图，其余文字请勿赘述；
- （二）不做必须要求，有完成的同学请提交Python代码和运行结果，文件保存目录参照要求2。
- 个人总结，包括但不限于实验难度、实验过程遇到的困难及解决办法，个人感想，不少于200字。