• 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

    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。

    def del_flow_table():
        url = 'http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/'
        res = requests.delete(url, auth=HTTPBasicAuth('admin', 'admin'))
        print(f"resp of del request is: {str(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。

    def out_flow_table():
        url = 'http://127.0.0.1:8181/restconf/config/opendaylight-inventory:nodes/node/openflow:1/flow-node-inventory:table/0/flow/1'
           data = {
       	  "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"
       		}
       	  ]
       	}
           res = requests.put(url, json=data, auth=HTTPBasicAuth('admin', 'admin'))
           print(f"resp of out table request is: {str(res.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。

    def get_flow_table():
        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'
        res = requests.get(url, auth=HTTPBasicAuth('admin', 'admin'))
        print(f"resp of get table request is: {str(res.content)}")
    
    1. 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'
        data = {
    		"dpid": 1,
    		"cookie": 1,
    		"cookie_mask": 1,
    		"table_id": 0,
    		"hard_timeout": 20,
    		"priority": 65535,
    		"flags": 1,
    		"match":{
    		    "in_port":1
    		},
    		"actions":[
    
    		]
    	}
        res = requests.post(url, json=data)
        print (res.content)
    

    (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

    # mytopo.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())}
    
    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
    # scripts.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
    

    (二)进阶要求

    编程实现基本要求第2部分Ryu(3)中的VLAN划分。

    import json
    
    import requests
    
    if __name__ == "__main__":
        url = 'http://127.0.0.1:8080/stats/flowentry/add'
        flow1 = {
            "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
                }
            ]
        }
        flow2 = {
            "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
                }
            ]
        }
        flow3 = {
            "dpid": 1,
            "priority": 1,
            "match":{
                "vlan_vid": 0
            },
            "actions":[
                {
                    "type": "POP_VLAN",    
                    "ethertype": 33024     
                },
                {
                    "type": "OUTPUT",
                    "port": 1
                }
            ]
        }
        flow4 = {
            "dpid": 1,
            "priority": 1,
            "match": {
                "vlan_vid": 1
            },
            "actions": [
                {
                    "type": "POP_VLAN", 
                    "ethertype": 33024  
                },
                {
                    "type": "OUTPUT",
                    "port": 2
                }
            ]
        }
        flow5 = {
            "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
                }
            ]
        }
        flow6 = {
            "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
                }
            ]
        }
        flow7 = {
            "dpid": 2,
            "priority": 1,
            "match": {
                "vlan_vid": 0
            },
            "actions": [
                {
                    "type": "POP_VLAN", 
                    "ethertype": 33024  
                },
                {
                    "type": "OUTPUT",
                    "port": 1
                }
            ]
        }
        flow8 = {
            "dpid": 2,
            "priority": 1,
            "match": {
                "vlan_vid": 1
            },
            "actions": [
                {
                    "type": "POP_VLAN", 
                    "ethertype": 33024  
                },
                {
                    "type": "OUTPUT",
                    "port": 2
                }
            ]
        }
        res1 = requests.post(url, json=flow1)
        res2 = requests.post(url, json=flow2)
        res3 = requests.post(url, json=flow3)
        res4 = requests.post(url, json=flow4)
        res5 = requests.post(url, json=flow5)
        res6 = requests.post(url, json=flow6)
        res7 = requests.post(url, json=flow7)
        res8 = requests.post(url, json=flow8)
    

    实验总结

    1. 实验中遇到的问题
      运行ryu却无法ping通
      解决办法:curl -X GET http://localhost:8080/stats/flow/1查看流表,将OpenFlow协议由1.0改为1.3以后可以ping通
    2. 实验心得
      本次实验难度真的可以说是很大。主要涉及了python的requests库,OpenDaylight及Ryu的RestfulAPI,对于这些方面,我之前不是很熟悉,利用本次机会进行了一番学习。本次实验对源码分析和对openflow协议的理解的要求进一步提高,在OpenFlow协议方面遇到了一些问题,但还是通过查资料以及询问同学很好的解决了。在学习完本次实验后,我已经能够编写程序调用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。通过本次实验进一步加深了我对代码的理解,对我的学习有很大的帮助。
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  • 原文地址:https://www.cnblogs.com/zhaoruiyan955/p/15452059.html
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