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

  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；
  • sudo mn --topo=single,3 --mac --controller=remote,ip=127.0.0.1,port=6633 --switch ovsk,protocols=OpenFlow13构建拓扑

（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。

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

def del_flowtable(url):
	resp = requests.delete(url, headers=headers)
	return resp

if __name__ == "__main__":
	url = "http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/"
	resp = del_flowtable(url)
	print(resp.content)
  • 执行结果

（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。

import requests
from requests.auth import HTTPBasicAuth

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

def dump_flowtable(url, jstr):
	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("./flowtable1.json") as f:
		jstr = f.read()
	resp = dump_flowtable(url, jstr)
	print(resp.content)
  • 其中， flowtable1.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"
    }
  ]
}
  • 执行结果

（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
from requests.auth import HTTPBasicAuth

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

def get_flowtable(url):
	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"
	resp = get_flowtable(url)
	print(resp.content)
  • 执行结果
  1. Ryu
  • 开启Ryu控制器 ryu-manager ryu.app.simple_switch_13 ryu.app.ofctl_rest
    （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

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

def dump_flowtable(url, jstr):
	resp = requests.put(url, jstr, headers=headers)
	return resp

if __name__ == "__main__":
	url = "http://127.0.0.1:8080/stats/flowentry/add"
	with open("./flowtable2.json") as f:
		jstr = f.read()
	resp = dump_flowtable(url, jstr)
	print(resp.content)
  • 其中， flowtable2.json
{
    "dpid": 1,
    "cookie": 1,
    "cookie_mask": 1,
    "table_id": 0,
    "hard_timeout": 20,
    "priority": 65535,
    "flags": 1,
    "match":{
        "in_port":1
    },
    "actions":[

    ]
 }
  • 执行结果

（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。

  • 其中， 拓扑代码
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())}
  • 构建拓扑
    sudo 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。

VLAN_ID Hosts
0 h1 h3
1 h2 h4
  • 删除流表
curl -X DELETE http://localhost:8080/stats/flowentry/clear/1
curl -X DELETE http://localhost:8080/stats/flowentry/clear/2
  • Shell脚本
# 将主机1，2发送来的包打上vlan标记
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

# 将主机3，4发送来的包取出vlan标记
 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

# 将主机3，4发送来的包打上vlan标记
 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
  • 执行结果

（二）进阶要求

编程实现基本要求第2部分Ryu（3）中的VLAN划分。

  • Python代码
#!/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",     # 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
            }
        ]
    }
    flow2 = {
        "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
            }
        ]
    }
    flow3 = {
        "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
            }
        ]
    }
    flow4 = {
        "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
            }
        ]
    }
    flow5 = {
        "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
            }
        ]
    }
    flow6 = {
        "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
            }
        ]
    }
    flow7 = {
        "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
            }
        ]
    }
    flow8 = {
        "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
            }
        ]
    }
    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)
  • 执行结果

个人总结

实验难度

总体适中，shell脚本和进阶部分较难，花费时间较久
本次实验主要任务在于动手实践编写程序调用OpenDaylight REST API实现特定网络功能 以及 编写程序调用Ryu REST API实现特定网络功能。本次实验的实验内容主要内容在先前实验的基础上进行，因此兼顾综合之前大部分的实验内容与知识。也因此，实验内容的难度也相应有所提升，所以本次实验所耗费时间相对较久。但同时也让我对于Open DayLight 和 Ryu的使用和北向API都有了更加深刻的了解，对于request包的使用也有了一定量的复习。

遇到问题

  • 遭遇问题：使用ryu-manager ryu.app.simple_switch_13 但是总是无法正常使用编写好的代码下发流表, 具体情况如下
  • 解决方法：之后参考Ryu官方文档和与其他同学交流，发先必须加上ryu.app.ofctl_rest，才能正常操作8080端口
  • 遭遇问题：以及我的虚拟机的ODL又双叒叕连不上（详情见实验四PTSD），但这次好像之前的解决方法不太奏效
  • 解决方法：因为重启和sudo mn -c重复几次了都没有用，所以我干脆直接重装了ODL
cd ./OpenDaylight
rm -rf distribution-karaf-0.6.4-Carbon

然后再重新解压安装装feature，最后薛定谔般的正常了。

实验心得

本次实验通过实践动手进行python编程，练习了如何使用OpenDaylight REST API和Ryu REST API实现调用网络功能。在动手过程中，再次复习之前实验中的相关知识及mininet指令和shell脚本，使我对ODL 以及 Ryu的知识理解记忆更加鲜明且深刻，对mininet指令使用更加熟练。同时，在本次的进阶实验中，为了完成实验，我也去阅读查看了Ryu和ODL的官方文档，吸收理解了一定与其有关的官方专业知识，也为我们SDN大作业的实现方法，进一步定下了一定实现基础。

posted @ 2021-10-23 21:47  Excalibur_Morgan  阅读(161)  评论(0)  编辑  收藏  举报