Floodlight Static Flow Pusher API

什么是 Static Flow Pusher?

Static Flow Pusher 是一个 Floodlight 模块，使用的是REST API接口,允许用户在OpenFlow 网络中插入流表 。

主动式和反应式流插入

OpenFlow 支持两种流表插入: 主动式和反应式。当数据包抵达OpenFlow交换机，而交换机没有该包对应的匹配流表时，反应时流表插入起作用。该数据包被送到控制器，由控制器进行评估，并向交换机添加相应的流表，从而把该数据包正确的转发出去。主动式插入则是在数据包到达之前就插入相应的流表，这就是两种方式的区别。

Static Flow Pusher 对于主动式流表插入很有用。Floodlight 默认会加载 Forwarding模块， 该模块使用反应式流插入 ，如果你只想使用静态流，你可以在floodlight.properties配置文件中删除 Forwarding。

API 概要

URI	Description	Arguments
/wm/staticflowentrypusher/json	静态流添加或删除操作	HTTP POST data (add flow), HTTP DELETE (for deletion)
/wm/staticflowentrypusher/list//json	列举交换机的静态流表	switch: Valid Switch DPID (XX:XX:XX:XX:XX:XX:XX:XX) or "all"
/wm/staticflowentrypusher/clear//json	清除交换机的静态流表	switch: Valid Switch DPID (XX:XX:XX:XX:XX:XX:XX:XX) or "all"

添加静态流操作

静态流添加是通过REST API接口来进行的。例如，在交换机1上插入一条让数据包从端口1进端口2出的流表，则可以使用curl命令。 第二个命令可以显示插入的流表。

curl -d '{"switch": "00:00:00:00:00:00:00:01", "name":"flow-mod-1", "priority":"32768", "ingress-port":"1","active":"true", "actions":"output=2"}' http://:8080/wm/staticflowentrypusher/json

curl http://:8080/wm/core/switch/1/flow/json;

删除静态流操作

通过包含流表名字的 HTTP DELETE命令来删除指定流表。

curl -X DELETE -d '{"name":"flow-mod-1"}' http://:8080/wm/staticflowentrypusher/json

 flow entry的可能属性

Key	Value	Notes
switch		ID of the switch (data path) that this rule should be added to   xx:xx:xx:xx:xx:xx:xx:xx
name		Name of the flow entry, this is the primary key, it MUST be unique
actions	=	See table of actions below   Specify multiple actions using a comma-separated list   Specifying no actions will cause the packets to be dropped
priority		default is 32767   maximum value is 32767
active
wildcards
ingress-port		switch port on which the packet is received   Can be hexadecimal (with leading 0x) or decimal
src-mac		xx:xx:xx:xx:xx:xx
dst-mac		xx:xx:xx:xx:xx:xx
vlan-id		Can be hexadecimal (with leading 0x) or decimal
vlan-priority		Can be hexadecimal (with leading 0x) or decimal
ether-type		Can be hexadecimal (with leading 0x) or decimal
tos-bits		Can be hexadecimal (with leading 0x) or decimal
protocol		Can be hexadecimal (with leading 0x) or decimal
src-ip		xx.xx.xx.xx
dst-ip		xx.xx.xx.xx
src-port		Can be hexadecimal (with leading 0x) or decimal
dst-port		Can be hexadecimal (with leading 0x) or decimal

Possible actions within the "action" field:

Key	Value	Notes
output	all   controller   local   ingress-port   normal   flood	no "drop" option   (instead, specify no action to drop packets)
enqueue	:	First number is port number, second is queue ID   Can be hexadecimal (with leading 0x) or decimal
strip-vlan
set-vlan-id		Can be hexadecimal (with leading 0x) or decimal
set-vlan-priority		Can be hexadecimal (with leading 0x) or decimal
set-src-mac		xx:xx:xx:xx:xx:xx
set-dst-mac		xx:xx:xx:xx:xx:xx
set-tos-bits
set-src-ip		xx.xx.xx.xx
set-dst-ip		xx.xx.xx.xx
set-src-port		Can be hexadecimal (with leading 0x) or decimal
set-dst-port		Can be hexadecimal (with leading 0x) or decimal

静态流表插入的实际应用

我们可以使用Python脚本写流表操作， 例如, 使用mininet产生一个简单的拓扑，并连接上控制器,默认的拓扑是一个交换机（s1）和两个主机（h2和h3）。

sudo mn --controller=remote --ip= --port=6633

下面的代码插入从h2到h3的流和h3到h2的流。

import httplib
import json

class StaticFlowPusher(object):

    def __init__(self, server):
        self.server = server

    def get(self, data):
        ret = self.rest_call({}, 'GET')
        return json.loads(ret[2])

    def set(self, data):
        ret = self.rest_call(data, 'POST')
        return ret[0] == 200

    def remove(self, objtype, data):
        ret = self.rest_call(data, 'DELETE')
        return ret[0] == 200

    def rest_call(self, data, action):
        path = '/wm/staticflowentrypusher/json'
        headers = {
            'Content-type': 'application/json',
            'Accept': 'application/json',
            }
        body = json.dumps(data)
        conn = httplib.HTTPConnection(self.server, 8080)
        conn.request(action, path, body, headers)
        response = conn.getresponse()
        ret = (response.status, response.reason, response.read())
        print ret
        conn.close()
        return ret

pusher = StaticFlowPusher('"00:00:00:00:00:00:00:01",
    "name":"flow-mod-1",
    "cookie":"0",
    "priority":"32768",
    "ingress-port":"1",
    "active":"true",
    "actions":"output=flood"
    }

flow2 =	{
    'switch':"00:00:00:00:00:00:00:01",
    "name":"flow-mod-2",
    "cookie":"0",
    "priority":"32768",
    "ingress-port":"2",
    "active":"true",
    "actions":"output=flood"
    }

pusher.set(flow1)
pusher.set(flow2)

通过ping命令进行测试

 mininet> h2 ping h3

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