基于REST API的SDN北向应用实践

Posted 2021-10-24 爱打瞌睡

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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。

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或Berrylium版本）、Postman和Ryu；3

基本要求

OpenDaylight

（1）

利用Mininet平台搭建下图所示网络拓扑，并连接OpenDaylight；

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

连接open daylight：./211906129/opendaylight/distribution-karaf-0.6.4-Carbon/bin/karaf

（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。

nano t1.py

def http_detele(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/\'
    with open(\'t1.json\') as f:
        jstr = f.read()
    resp = http_detele(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：

nano t1.py

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(\'t1.json\') as f:
      jstr = f.read()
      resp = http_get(url)
      print(resp.content)

（4）

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

python：

基本要求

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。

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(\'r1.json\') as f:
        jstr = f.read()
    resp = http_post(url,jstr)
    print (resp.content)

json：

{
  "dpid": 1,
  "match": {
    "in-port": "1",
    "dl_dst": "00:00:00:00:00:03"
  },
  "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。

连接Ryu：ryu-manager ryu/ryu/app/gui_topology/gui_topology.py --observe-links

（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

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

个人总结：这次的实验相对前面几次实验是比较难的、比较麻烦的，尝试了很多次，按照前面完成的同学的思路，一步一步来，其中，编写python和json文件时，要用到的是nano ***.py/json。做完实验还是不知道代码是什么意思，然后opendalight部分的中断h1 ping h3 20s时有点瑕疵，我只中断了10s，所以运行了2次python t1.py代码。然后ryu部分利用mininet平台搭建网络拓扑时，出现 File exists 问题，再来就是Shell脚本，这是完全没看懂，就借鉴了同学的代码。对于我来说，代码这块是个问题，所以以后要努努力，不会敲代码，但是至少也要读懂代码。

SDN实验---Ryu的应用开发北向接口RESTAPI

一：推文

软件定义网络基础---REST API概述

软件定义网络基础---REST API的设计规范

二：掌握Ryu基本RESTAPI使用方法

（一）Ryu的RESTAPI

（二） REST应用样例：app/ofctl_rest.py

1.所提供的样例API接口

# REST API
#

# Retrieve the switch stats
#
# get the list of all switches
# GET /stats/switches
#
# get the desc stats of the switch
# GET /stats/desc/<dpid>
#
# get flows desc stats of the switch
# GET /stats/flowdesc/<dpid>
#
# get flows desc stats of the switch filtered by the fields
# POST /stats/flowdesc/<dpid>
#
# get flows stats of the switch
# GET /stats/flow/<dpid>
#
# get flows stats of the switch filtered by the fields
# POST /stats/flow/<dpid>
#
# get aggregate flows stats of the switch
# GET /stats/aggregateflow/<dpid>
#
# get aggregate flows stats of the switch filtered by the fields
# POST /stats/aggregateflow/<dpid>
#
# get table stats of the switch
# GET /stats/table/<dpid>
#
# get table features stats of the switch
# GET /stats/tablefeatures/<dpid>
#
# get ports stats of the switch
# GET /stats/port/<dpid>[/<port>]
# Note: Specification of port number is optional
#
# get queues stats of the switch
# GET /stats/queue/<dpid>[/<port>[/<queue_id>]]
# Note: Specification of port number and queue id are optional
#       If you want to omitting the port number and setting the queue id,
#       please specify the keyword "ALL" to the port number
#       e.g. GET /stats/queue/1/ALL/1
#
# get queues config stats of the switch
# GET /stats/queueconfig/<dpid>[/<port>]
# Note: Specification of port number is optional
#
# get queues desc stats of the switch
# GET /stats/queuedesc/<dpid>[/<port>[/<queue_id>]]
# Note: Specification of port number and queue id are optional
#       If you want to omitting the port number and setting the queue id,
#       please specify the keyword "ALL" to the port number
#       e.g. GET /stats/queuedesc/1/ALL/1
#
# get meter features stats of the switch
# GET /stats/meterfeatures/<dpid>
#
# get meter config stats of the switch
# GET /stats/meterconfig/<dpid>[/<meter_id>]
# Note: Specification of meter id is optional
#
# get meter desc stats of the switch
# GET /stats/meterdesc/<dpid>[/<meter_id>]
# Note: Specification of meter id is optional
#
# get meters stats of the switch
# GET /stats/meter/<dpid>[/<meter_id>]
# Note: Specification of meter id is optional
#
# get group features stats of the switch
# GET /stats/groupfeatures/<dpid>
#
# get groups desc stats of the switch
# GET /stats/groupdesc/<dpid>[/<group_id>]
# Note: Specification of group id is optional (OpenFlow 1.5 or later)
#
# get groups stats of the switch
# GET /stats/group/<dpid>[/<group_id>]
# Note: Specification of group id is optional
#
# get ports description of the switch
# GET /stats/portdesc/<dpid>[/<port_no>]
# Note: Specification of port number is optional (OpenFlow 1.5 or later)

# Update the switch stats
#
# add a flow entry
# POST /stats/flowentry/add
#
# modify all matching flow entries
# POST /stats/flowentry/modify
#
# modify flow entry strictly matching wildcards and priority
# POST /stats/flowentry/modify_strict
#
# delete all matching flow entries
# POST /stats/flowentry/delete
#
# delete flow entry strictly matching wildcards and priority
# POST /stats/flowentry/delete_strict
#
# delete all flow entries of the switch
# DELETE /stats/flowentry/clear/<dpid>
#
# add a meter entry
# POST /stats/meterentry/add
#
# modify a meter entry
# POST /stats/meterentry/modify
#
# delete a meter entry
# POST /stats/meterentry/delete
#
# add a group entry
# POST /stats/groupentry/add
#
# modify a group entry
# POST /stats/groupentry/modify
#
# delete a group entry
# POST /stats/groupentry/delete
#
# modify behavior of the physical port
# POST /stats/portdesc/modify
#
# modify role of controller
# POST /stats/role
#
#
# send a experimeter message
# POST /stats/experimenter/<dpid>

（三）Ryu官方文档：https://ryu.readthedocs.io/en/latest/app/ofctl_rest.html

三：实验开始

（一）开启Ryu控制器

ryu-manager ofctl_rest.py simple_switch_13.py --observe-links --verbose　　#除了使用RESTAPI之外，我们还要保证ryu控制器正常处理交换机逻辑

（二）开启Mininet

sudo mn --controller=remote --mac --topo=tree,2,2

（三）使用Curl发送URL请求

1.获取到所有交换机Get the list of all switches which connected to the controller.

$ curl -X GET http://localhost:8080/stats/switches

2.获取交换机的描述信息Get the desc stats of the switch which specified with Datapath ID in URI.

$ curl -X GET http://localhost:8080/stats/desc/1

3.其他类似

（四）Postman实验（更美观）

1.安装postman

2.获取交换机信息

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