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
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。
delete.py
#!/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'}
res = requests.delete(url, headers=headers, auth=HTTPBasicAuth('admin', 'admin'))
print (res.content)
（3） 下发硬超时流表，实现拓扑内主机h1和h3网络中断20s。
timeOut.py
#!/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/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
# 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"
}
]
}
（4） 获取s1上活动的流表数。
getflow.py
# 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)
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。
ryu_timeout.py
# ryu_timeout.py
import requests
if __name__ == "__main__":
url = 'http://127.0.0.1:8080/stats/flowentry/add'
with open("./ryu_timeout.json") as file:
str = file.read()
headers = {'Content-Type': 'application/json'}
res = requests.post(url, str, headers=headers)
print (res.content)
ryu_timeout.json
# 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":[
]
}
（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
| VLAN_ID Hosts | |
|---|---|
| 0 | h1 h3 |
| 1 | h2 h4 |
创建拓扑图
sudo mn --custom mytopo.py --topo mytopo --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13
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())}
shell.sh
curl -X POST -d '{
"dpid": 1,
"priority": 1,
"match":{
"in_port": 1
},
"actions":[
{
"type": "PUSH_VLAN", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # Set VLAN ID
"value": 4096 # Describe sum of vlan_id(e.g. 6) | OFPVID_PRESENT(0x1000=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", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # Set VLAN ID
"value": 4097 # Describe sum of vlan_id(e.g. 6) | OFPVID_PRESENT(0x1000=4096)
},
{
"type": "OUTPUT",
"port": 3
}
]
}' http://localhost:8080/stats/flowentry/add
curl -X POST -d '{
"dpid": 1,
"priority": 1,
"match":{
"vlan_vid": 0
},
"actions":[
{
"type": "POP_VLAN", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"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", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"type": "OUTPUT",
"port": 2
}
]
}' http://localhost:8080/stats/flowentry/add
curl -X POST -d '{
"dpid": 2,
"priority": 1,
"match":{
"in_port": 1
},
"actions":[
{
"type": "PUSH_VLAN", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # Set VLAN ID
"value": 4096 # Describe sum of vlan_id(e.g. 6) | OFPVID_PRESENT(0x1000=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", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"type": "SET_FIELD",
"field": "vlan_vid", # Set VLAN ID
"value": 4097 # Describe sum of vlan_id(e.g. 6) | OFPVID_PRESENT(0x1000=4096)
},
{
"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", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"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", # Push a new VLAN tag if a input frame is non-VLAN-tagged
"ethertype": 33024 # Ethertype 0x8100(=33024): IEEE 802.1Q VLAN-tagged frame
},
{
"type": "OUTPUT",
"port": 2
}
]
}' http://localhost:8080/stats/flowentry/add
（三）实验小结
在本次实验中我学习到了如何编写程序调用OpenDaylight REST API实现特定网络功能、如何编写程序调用Ryu REST API实现特定网络功能
。在实验中，我使用了python程序下发指令删除s1上的游标数据、下发硬超时流表，实现拓扑内主机h1和h3网络中断20s、获取s1上活动的流表数。总得来说本次实验难度很大，我是做了几个小时才做完，期间遇到了很多不会的问题，通过百度和询问同学得到了解决。我没有做进阶但实验过程还算顺利，我在本次实验中体验到了如何使用python程序来操控网络功能，本次实验受益良多，希望在接下来的学习中能获得更多的知识。