实验7：基于REST API的SDN北向应用实践

2024-01-14 14:55:22

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；

（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
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)

（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。

python文件：

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

json文件：

{
"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。

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/operational/opendaylight-inventory:nodes/node/openflow:1/flow-node-inventory:table/0/opendaylight-flow-table-statistics:flow-table-statistics'
with open('test.json') as f:
jstr = f.read()
resp = http_get(url)
print(resp.content)

3.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
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('ryutest.json') as f:
jstr = f.read()
resp = http_post(url,jstr)
print (resp.content)

{
"dpid": 1,
"match": {
"in-port": "1",
"dl_dst": "00:00:00:00:00:01"
},
"priority": 65535,
"hard_timeout": 20,
"cookie": "2",
"table_id": 0,
"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。

（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_ID|Hosts|
|:--|:--|
|0|h1 h3|
|1|h2 h4|

注：输入方式是命令行

curl -X POST -d '{
"dpid": 1,
"match": {
"in_port": 1
},
"actions": [
{
"type": "PUSH_VLAN",
"ethertype": 33024
},
{
"type": "SET_FIELD",
"field": "vlan_vid",
"value": 4096
},
{
"type":"OUTPUT",
"port": 3
}
],
"priority":5
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '
{
"dpid": 1,
"priority":5,
"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": 1,
"match": {
"vlan_vid": 0
},
"actions": [
{
"type": "POP_VLAN",
"ethertype": 33024
},
{
"type":"OUTPUT",
"port": 1
}
],
"priority":5
}
' http://localhost:8080/stats/flowentry/add

curl -X POST -d'
{
"dpid": 1,
"match": {
"vlan_vid": 1
},
"actions": [
{
"type": "POP_VLAN",
"ethertype": 33024
},
{
"type":"OUTPUT",
"port": 2
}
],
"priority":5
}
' http://localhost:8080/stats/flowentry/add

curl -X POST -d '{
"dpid": 2,
"match": {
"in_port": 1
},
"actions": [
{
"type": "PUSH_VLAN",
"ethertype": 33024
},
{
"type": "SET_FIELD",
"field": "vlan_vid",
"value": 4096
},
{
"type":"OUTPUT",
"port": 3
}
],
"priority":5
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '
{
"dpid": 2,
"match": {
"in_port": 2
},
"actions": [
{
"type": "PUSH_VLAN",
"ethertype": 33024
},
{
"type": "SET_FIELD",
"field": "vlan_vid",
"value": 4097
},
{
"type":"OUTPUT",
"port": 3
}
],
"priority":5
}' http://localhost:8080/stats/flowentry/add

curl -X POST -d '
{
"dpid": 2,
"match": {
"vlan_vid": 0
},
"actions": [
{
"type": "POP_VLAN",
"ethertype": 33024
},
{
"type":"OUTPUT",
"port": 1
}
],
"priority":5
}
' http://localhost:8080/stats/flowentry/add

curl -X POST -d'
{
"dpid": 2,
"match": {
"vlan_vid": 1
},
"actions": [
{
"type": "POP_VLAN",
"ethertype": 33024
},
{
"type":"OUTPUT",
"port": 2
}
],
"priority":5
}' http://localhost:8080/stats/flowentry/add

（二）进阶要求

编程实现基本要求第2部分Ryu（3）中的VLAN划分。

四、实验心得

本次实验是基于REST API的SDN北向应用实践，对于流表下发完全没有基础，实验效果也完全不明，全靠张炜龙等一系列先完成的同学，摸着石头过河完成的。实验现象还有许多不明确：

删除流表不配合下发硬超时会报{"errors":{"error":[{"error-type"错误，不清楚删除流表的实验现象；不知道是我的原因还是就是这个流程，我的ryu中的app和ryu视图不能同时启动，导致流程是先启动ryu的switch，然后mininet连接，断开switch.py连接视图，然后启动硬超时python代码，注dl_dst是调整主机的连通性00:00:00:00:00:01是主机1，以此类推。

实验整体迷迷糊糊的，搜索了很多资料，勉勉强强完成。看得出来这部分应该还是基础内容，估摸着接下来的实验和大作业估计够呛。

存一下链接以后估计用的上：https://ryu.readthedocs.io/en/latest/app/ofctl_rest.html#update-the-switch-stats

　　　　　　　　　　　　https://blog.csdn.net/qq_34039018/article/details/89136146

　　　　　　　　　　　　https://blog.csdn.net/weixin_39793434/article/details/111509659

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