实验7：基于REST API的SDN北向应用实践
（一）基本要求
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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；- 生成topo
sudo mn --topo=single,3 --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13- 启动OpendDaylight
./distribution-karaf-0.4.4-Beryllium-SR4/bin/karaf
（2） 下发指令删除s1上的流表数据。
- delete.py
（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
- timeout.json
（4）获取s1上活动的流表数
- get_flows.py
2.编写Python程序，调用Ryu的北向接口实现以下功能
- 打开ryu
ryu-manager ryu.app.simple_switch_13 ryu.app.ofctl_rest（1） 实现上述OpenDaylight实验拓扑上相同的硬超时流表下发。
- ryu_timeout.py
#!/usr/bin/python import requests from requests.auth import HTTPBasicAuth def http_post(url,jstr): url = url headers = {'Content-Type':'application/json'} resp = requests.post(url,jstr,headers=headers) return resp if __name__ == "__main__": url = 'http://127.0.0.1:8080/stats/flowentry/add' with open("./ryu_timeout.json") as f: jstr = f.read() resp = http_post(url,jstr) print (resp.content)- 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
ryu_vlan.py
ryu_vlan.json
#!/usr/bin/python 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)- 下载curl
sudo apt install curl- topo连接控制器
sudo mn --custom ryu_topo.py --topo ryu_topo --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13
- 删除流表
curl -X DELETE http://127.0.0.1:8080/stats/flowentry/clear/1curl -X DELETE http://127.0.0.1:8080/stats/flowentry/clear/2
（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。
- getnodes.py
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()- 运行结果
(三)实验心得
这次实验比以往都难很多，对同学的依赖很大，实验也做得不好，代码上也还有很多没理解，本次实验需要不断查阅文档资料，进一步学习到了ODL REST API和Ryu REST API的使用，进一步学习到了ODL和Ryu北向接口的使用。
通过这实验，我对ODL和ryu都有了更深的理解，但也还有很多的不理解，需要更加的努力。
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