实验7:基于REST API的SDN北向应用实践

(1) 利用Mininet平台搭建下图所示网络拓扑,并连接OpenDaylight;

(2) 编写Python程序,delet.py,调用OpenDaylight的北向接口下发指令删除s1上的流表数据。

点击查看代码
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/'
    headers = {'Content-Type': 'application/json'}
    response = requests.delete(url=url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
    print(response.content)


(3) 编写Python程序,调用OpenDaylight的北向接口下发硬超时流表,实现拓扑内主机h1和h3网络中断20s
.timeout.py

点击查看代码
#!/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)

.json
点击查看代码
{
    "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) 编写Python程序,get_flows.py,调用OpenDaylight的北向接口获取s1上活动的流表数。

点击查看代码
#!/usr/bin/python
import requests
from requests.auth import HTTPBasicAuth
def http_get(url):
    url= url
    headers = {'Content-Type':'application/json'}
    resp = requests.get(url,headers=headers,auth=HTTPBasicAuth('admin','admin'))
    return resp

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'
    resp = http_get(url)
    print(resp.content)

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

.ryu_timeout.py

点击查看代码
import requests
from requests.auth import HTTPBasicAuth

if __name__ == '__main__':
    url = 'http://127.0.0.1:8080/stats/flowentry/add'
    headers = {'Content-Type': 'application/json'}
    json = open('ryu_timeout.json').read()
    response = requests.post(url, data=json, headers=headers)
    print(response.content)

.ryu_timeout.json

点击查看代码
{
    "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_ID HOST
0 h1、h3
1 h2、h4

.根据VLAN实验的网络拓扑编写ryu_topo.py

点击查看代码
from mininet.topo import Topo
 
class ryu_topo(Topo):
    def __init__(self):
        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 = {'ryu_topo': (lambda: ryu_topo())}


.编写符合vlan的set.py代码

点击查看代码
#!/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)


连接ryu,构建拓扑,执行set.py

三.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。
(1)get.py

点击查看代码
import requests
import time
import re


class GetInformation:
    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 get_flow_table(self):
        url = 'http://' + self.ip + '/stats/flow/%d'
        list_switch = self.get_switch_id()
        all_flow = []
        for switch in list_switch:
            new_url = format(url % int(switch, 16))
            re_switch_flow = requests.get(url=new_url).json()
            all_flow.append(re_switch_flow)
        return all_flow

    def show_flow(self):
        list_flow = self.get_flow_table()
        for flow in list_flow:
            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)
                    
    def show_name(self):
        list_flow = self.get_flow_table()
        for flow in list_flow:
            for dpid in flow.keys():
                dp_id = dpid
                switchnum= '{1}'.format(hex(int(dp_id)), int(dp_id))        
                print('s'+switchnum)
                switchnum = int(switchnum)
            for list_table in flow.values():
                count = 0
                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')
                        if num == '1' and switchnum == 1:
                            print('h2')
                        if num == '0' and switchnum == 2:
                            print('h3')
                        if num == '1' and switchnum == 2:
                            print('h4')

S1 = GetInformation("127.0.0.1:8080");
S1.show_name();
S1.show_flow();

四.个人总结
本次实验我学到了编写程序调用OpenDaylight REST API和Ryu REST API实现特定网络功能。本次实验的编写程序对我来说比较困难。用到了之前OpenDaylight和Ryu的相关知识,经过复习才顺利完成。经过这次实验,我大致了编写程序调用OpenDaylight REST API和Ryu REST API实现特定网络功能。重新回顾PDF文档熟悉了相关控制器的使用,对控制器的启动,下发流表等操作更熟悉了,并且在实践中通过阅读相关文档,查阅资料,了解到了北向接口API其实并没有一个统一的标准,不同的控制器对应着的API也有所区别,体会到了SDN框架的灵活性和可编程性。实验的第一部分总体比较简单,使我困惑的地方在配置vlan时无法实现,删除流表的工具也出了问题,最后改了代码发现不需要删除流表,代码有所参考,实验的第二部分有一定难度,有所参考后最终解决了问题

posted @ 2022-11-02 20:08  212002125王昊  阅读(15)  评论(0编辑  收藏  举报