实验7：基于REST API的SDN北向应用实践

标签：__ url flow REST headers API SDN type requests

（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

    （2） 下发指令删除s1上的流表数据。

    （3） 下发硬超时流表，实现拓扑内主机h1和h3网络中断20s。

    （4） 获取s1上活动的流表数。

 

下发硬超时流表:

#!/usr/bin/python
import requests
from requests.auth import HTTPBasicAuth
def http_put(url,jstr):
    url= url
    headers = {'Content-Type':'application/json'}
    resp = requests.put(url,jstr,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/flow-node-inventory:table/0/flow/1'
    with open('./hto.json') as f:
        jstr = f.read()
    resp = http_put(url,jstr)
    print (resp.content)

{
    "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": "flow1",
            "priority": "65535",
            "hard-timeout": "20",
            "cookie": "2",
            "table_id": "0"
        }
    ]
}

 

 

 

 

查看流表数量:

#！/usr/bin/python
import requests
import json
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/config/opendaylight-inventory:nodes/node/openflow:1/flow-node-inventory:table/0'
    resp = http_get(url)
    res = json.loads(resp.text)
    print(len(res['flow-node-inventory:table'][0]['flow']))

 

 

删除流表：

#!/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)

 

 

 

 

 

 

 

2.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。

    （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

 

下发硬超时流表:

#!/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_hto.json') as f:
        jstr = f.read()
    resp = http_post(url,jstr)
    print (resp.content)

{
    "dpid": 1,
    "cookie": 1,
    "cookie_mask": 1,
    "table_id": 0,
    "hard_timeout": 20,
    "priority": 65535,
    "flags": 1,
    "match":{
        "in_port":1
    },
    "actions":[
    
    ]
 }

 

 

 

 

VLAN配置：

#!/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)

 

 

 

 

 

 

（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 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();

 

 

 

 

 

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。在启动 simple_switch_13.py 时没有一起运行 ofctl_rest.py 开启控制器的北向接口，导致下发流表失败。在编程实现相同的VLAN配置时，运行Python代码后无法实现相同的VLAN配置，经过上网查询后得知需要先使用 curl -X DELETE http://localhost:8080/stats/flowentry/clear/1 和 curl -X DELETE http://localhost:8080/stats/flowentry/clear/2 删除流表。在进阶实验查看流表时报错 s1.mgmt: version negotiation failed (we support version 0x01, peer supports version 0x04)ovs-ofctl: s1: failed to connect to socket (Broken pipe) ，经过上网查询后发现原因是mininet创建拓扑的命令使用了OpenFlow 1.3版本而 dpctl dump-flows 命令默认是1.0版本，因此需要在 dpctl dump-flows 命令中指定OpenFlow 版本，即 dpctl dump-flows -O -OpenFlow13 。

标签：__,url,flow,REST,headers,API,SDN,type,requests
From： https://www.cnblogs.com/zsy222/p/16823541.html