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实验7：基于REST API的SDN北向应用实践

jjjcjazrr 2021-10-27 16:22 原文

一、实验目的

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

二、实验环境

1.下载虚拟机软件Oracle VisualBox或VMware；
2.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；

./distribution-karaf-0.6.4-Carbon/bin/karaf 
sudo mn --topo=single,3 --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13
pingall

（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。

#delete.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/'

headers = {'Content-Type': 'application/json'}

res = requests.delete(url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))

print (res.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。

# delay.py
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('delay.json') as f:

jstr = f.read()

resp = http_put(url,jstr)

print (resp.content)

# delay.json
{          //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": "flow1",
"priority": "65535",
"hard-timeout": "20",
"cookie": "2",
"table_id": "0"
} ] }

（4） 编写Python程序，调用OpenDaylight的北向接口获取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.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。

import requests

if name == "main":

url = 'http://127.0.0.1:8080/stats/flowentry/add'

with open("./RyuDelay.json") as f:

jstr = f.read()

headers = {'Content-Type': 'application/json'}

res = requests.post(url, jstr, headers=headers)

print (res.content)

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

]



}

（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。

 

 

#topo.py
from mininet.topo import Topo

class MyTopo(Topo):

def init(self):

# initilaize topology

Topo.init(self)


    self.addSwitch(</span><span style="color: #800000;">"</span><span style="color: #800000;">s1</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addSwitch(</span><span style="color: #800000;">"</span><span style="color: #800000;">s2</span><span style="color: #800000;">"</span><span style="color: #000000;">)

    self.addHost(</span><span style="color: #800000;">"</span><span style="color: #800000;">h1</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addHost(</span><span style="color: #800000;">"</span><span style="color: #800000;">h2</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addHost(</span><span style="color: #800000;">"</span><span style="color: #800000;">h3</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addHost(</span><span style="color: #800000;">"</span><span style="color: #800000;">h4</span><span style="color: #800000;">"</span><span style="color: #000000;">)

    self.addLink(</span><span style="color: #800000;">"</span><span style="color: #800000;">s1</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">h1</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addLink(</span><span style="color: #800000;">"</span><span style="color: #800000;">s1</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">h2</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addLink(</span><span style="color: #800000;">"</span><span style="color: #800000;">s2</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">h3</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addLink(</span><span style="color: #800000;">"</span><span style="color: #800000;">s2</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">h4</span><span style="color: #800000;">"</span><span style="color: #000000;">)
    self.addLink(</span><span style="color: #800000;">"</span><span style="color: #800000;">s1</span><span style="color: #800000;">"</span>, <span style="color: #800000;">"</span><span style="color: #800000;">s2</span><span style="color: #800000;">"</span><span style="color: #000000;">)



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

 

 

（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。

 

 

# vlan.py
# 将主机1，2发送来的数据包打上vlan标记
curl -X POST -d '{
    "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
        }
    ]
 }' http://localhost:8080/stats/flowentry/add

 curl -X POST -d '{
    "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
        }
    ]
 }' http://localhost:8080/stats/flowentry/add

# 将主机3，4发送来的数据包取出vlan标记

curl -X POST -d '{

"dpid": 1,

"priority": 1,

"match":{

"vlan_vid": 0

},

"actions":[

{

"type": "POP_VLAN",

"ethertype": 33024

},

{

"type": "OUTPUT",

"port": 1

}

]

}' http://localhost:8080/stats/flowentry/add



curl -X POST -d '{

"dpid": 1,

"priority": 1,

"match":{

"vlan_vid": 1

},

"actions":[

{

"type": "POP_VLAN",

"ethertype": 33024

},

{

"type": "OUTPUT",

"port": 2

}

]

}' http://localhost:8080/stats/flowentry/add


# 将主机3，4发送来的数据包打上vlan标记

curl -X POST -d '{

"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

}

]

}' http://localhost:8080/stats/flowentry/add



curl -X POST -d '{

"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

}

]

}' http://localhost:8080/stats/flowentry/add



curl -X POST -d '{

"dpid": 2,

"priority": 1,

"match":{

"vlan_vid": 0

},

"actions":[

{

"type": "POP_VLAN",

"ethertype": 33024

},

{

"type": "OUTPUT",

"port": 1

}

]

}' http://localhost:8080/stats/flowentry/add



curl -X POST -d '{

"dpid": 2,

"priority": 1,

"match":{

"vlan_vid": 1

},

"actions":[

{

"type": "POP_VLAN",

"ethertype": 33024

},

{

"type": "OUTPUT",

"port": 2

}

]

}' http://localhost:8080/stats/flowentry/add

 

 

四.个人总结

这次实验耗时较长，解决了上次实验中没能完成的ryu安装问题，也学会了如何用终端口令直接创造py文件，以及使用终端下发流表，让我对ODL的操作以及ryu的操作都有了进一步深刻的理解。另外我发现建立拓扑后立刻执行pingall指令会出现无法连接的问题，但是稍等片刻或重新搭建拓扑后问题得以解决。

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