实验7：基于REST API的SDN北向应用实践

（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；                                                                                                                                                                                      

        • 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/1 
        curl -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。

         

原文地址：http://www.cnblogs.com/tldhgy/p/16854197.html

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