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

一、实验目的

能够编写程序调用OpenDaylight REST API实现特定网络功能；
能够编写程序调用Ryu REST API实现特定网络功能。

二、实验环境

下载虚拟机软件Oracle VisualBox或VMware；
在虚拟机中安装Ubuntu 20.04 Desktop amd64，并完整安装Mininet、OpenDaylight（Carbon版本）、Postman和Ryu；

三、实验要求

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

创建拓扑：sudo mn --topo=single,3 --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow10


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

#!/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/'
    headers = {'Content-Type':'application/json'}
    resp = requests.delete(url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
    print(resp)

（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。

#!/usr/bin/python
import requests
from requests.auth import HTTPBasicAuth

timeoutJson = {
    "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"
        }
    ]
}
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'
    jstr = str(timeoutJson)
    headers = {'Content-Type': 'application/json'}
    resp = requests.put(url, jstr, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
    print(resp.content,jstr)

（4） 编写Python程序，调用OpenDaylight的北向接口获取s1上活动的流表数。

# ！/usr/bin/python
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'}
    resp = requests.get(url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
    print(resp.content)

2.Ryu
（1） 编写Python程序，调用Ryu的北向接口，实现上述OpenDaylight实验拓扑上相同的硬超时流表下发。

#!/usr/bin/python
import requests

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

    ]
}
if __name__ == "__main__":
    url = 'http://127.0.0.1:8080/stats/flowentry/add'

    headers = {'Content-Type': 'application/json'}
    res = requests.post(url, str(timeoutJson), headers=headers)
    print(res.content)

（2） 利用Mininet平台搭建下图所示网络拓扑，要求支持OpenFlow 1.3协议，主机名、交换机名以及端口对应正确。拓扑生成后需连接Ryu，且Ryu应能够提供REST API服务。

#!/usr/bin/env python
from mininet.topo import Topo

class MyTopo(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 = {'mytopo': (lambda: MyTopo())}

连接ryu：ryu-manager ryu.app.simple_switch_13 ryu.app.ofctl_rest
创建拓扑：　sudo mn --custom myTopo.py --topo mytopo --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13

（3） 整理一个Shell脚本，参考Ryu REST API的文档，利用curl命令，实现和实验2相同的VLAN。

#!/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)

四、实验个人总结

- 实验难度　 本次实验难度较难，需要编写较多的代码，虽然有前几次实验的经验，但许多知识没经常使用又忘记了，一开始做起来没有头绪。要去查看之前实验的教程与相关文档，才顺利做完实验。 -　遇到的问题 使用ryu的接口时惯性使用OpenFlow1.0，导致下发流表之前的拓扑无法ping通 解决方案：建立拓扑时使用OpenFlow1.3即可以解决 -　实验感想 本次实验让我进一步了解了OpenDaylight和Ryu的使用，还复习了一遍有关的知识，巩固了有关知识点，了解了相关API的使用。