标签：__ url self flow REST headers API SDN requests

实验7：基于REST API的SDN北向应用实践

基础要求

1.编写Python程序，调用OpenDaylight的北向接口实现以下功能

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

下发指令删除s1上的流表数据

import requests as rq
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 = rq.delete(url=url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
    print(response.content)

下发硬超时流表，实现拓扑内主机h1和h3网络中断20s。

# timeout.py
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
{
    "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"
      }
    ]
  }

获取s1上活动的流表数。

# 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)

2.编写Python程序，调用Ryu的北向接口实现以下功能

实现上述OpenDaylight实验拓扑上相同的硬超时流表下发

# ryu_timeout.py
import requests
if __name__ == "__main__":
    url = 'http://127.0.0.1:8080/stats/flowentry/add'
    with open("./timeout_ryu.json") as file:
        str = file.read()
    headers = {'Content-Type': 'application/json'}
    res = requests.post(url, str, headers=headers)
    print (res.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":[

    ]
 }

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

# ryu_topo.py
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())}
# ryu_vlan.py
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)

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

# getall.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()

个人总结

在本次实验中，学习了SDN应用层与控制层之间的北向接口REST API。通过前几次实验所使用到的控制器对交换机以可编程的方式进行转发控制。与此同时，我又重新回顾熟悉了相关控制器的使用，对控制器的启动，下发流表等操作基本能快速顺利地完成，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，最后也得知了如何在程序中调用北向接口API，动态地修改控制流表，算是真正实际地体会到了SDN框架的灵活性和可编程性。在一开始的实验中，我发现自己对ODL、RYU等控制器的使用都还是比较生疏，尽管这些控制器在前几次的实验中均有涉及。因此，我重新复习了老师发过的几次实验指南书以及我之前撰写的实验报告博客，熟悉并巩固了对于这些常用控制器的使用，之后完成实验的速度明显加快，对于ODL和RYU等控制器的操作也愈发娴熟。

标签：__,url,self,flow,REST,headers,API,SDN,requests
From： https://www.cnblogs.com/032002427obk/p/16828196.html

实验7：基于REST API的SDN北向应用实践

实验7：基于REST API的SDN北向应用实践

基础要求

1.编写Python程序，调用OpenDaylight的北向接口实现以下功能

2.编写Python程序，调用Ryu的北向接口实现以下功能

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

个人总结

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