基于RYU的拓扑发现
基于RYU的拓扑发现
前言
本次实验是一个基于RYU的拓扑发现功能。参考了呈神的实现方式，并加了一些自己实现方式，做了一些数据结构的改动。
数据结构
-
link_to_port 字典
有两种关系：
一是记录交换机与交换机之间的链接 （src_dpid, src_port_no) => (dst_dpid, dst_port_no)
一是记录交换机与控制器之间的链接 (dpid, port_no) =>(mac, ip)
-
host_or_switch 字典
用来记录交换机连的端口连接的为何种类型的设备 （dpid, port_no) =>
1：交换机
2：主机
其他：没有连接
-
switch_port_table 字段
用来记录交换机的端口 , (dpid) => [1,2,....]
相关API的使用
API是基于ryu源代码topology/switches下的使用，并使用了三个api
- get_switch 获取交换机列表
- get_link 获取链路信息
- get_host 获取主机信息
实验代码
#-*- coding: UTF-8 -*-
import logging
from ryu.base import app_manager
from ryu.controller import ofp_event
from ryu.controller.handler import MAIN_DISPATCHER, DEAD_DISPATCHER
from ryu.controller.handler import CONFIG_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_0
from ryu.ofproto import ofproto_v1_2
from ryu.ofproto import ofproto_v1_3
from ryu.lib.packet import packet
from ryu.lib import hub
from ryu.topology import event, switches
from ryu.topology.api import get_switch, get_link, get_host
from ryu import cfg
CONF = cfg.CONF
class test_wpq(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION,
ofproto_v1_3.OFP_VERSION]
def __init__(self, *args, **kwargs):
super(test_wpq, self).__init__(*args, **kwargs)
self.topology_api_app = self
self.link_to_port = {}
self.host_or_switch = {}
self.switch_port_table = {}
self.name = "wpq"
self.discover_thread = hub.spawn(self._discover_links)
#A thread to output the information of topology
def _discover_links(self):
while True:
self.get_topology(None)
try:
self.show_topology()
except Exception as err:
print "please input pingall in mininet and wait a memment"
hub.sleep(5)
#add entry of table-miss
@set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
def switch_feature_handle(self, ev):
msg = ev.msg
print msg
datapath = msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
self.logger.info("switch %s is connected", datapath.id)
match = parser.OFPMatch()
actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER)]
self.add_flow(datapath=datapath, priority=0, actions=actions, match=match)
def add_flow(self, datapath, priority, actions, match, idle_timeout=0, hard_timeout=0):
ofp = datapath.ofproto
parser = datapath.ofproto_parser
inst = [parser.OFPInstructionActions(ofp.OFPIT_APPLY_ACTIONS,
actions)]
mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
idle_timeout=idle_timeout,
hard_timeout=hard_timeout,
match=match, instructions=inst)
datapath.send_msg(mod)
#fill the port of switch imformation
def create_map(self, switch_list):
for sw in switch_list:
dpid = sw.dp.id
self.switch_port_table.setdefault(dpid, set())
for p in sw.ports:
self.switch_port_table[dpid].add(p.port_no)
# print "--------------交换机端口情况---------------"
# print self.switch_port_table
#fill the link information
def create_link_port(self, link_list, host_list):
for link in link_list:
src = link.src
dst = link.dst
self.link_to_port[(src.dpid, src.port_no)] = (dst.dpid, dst.port_no)
self.link_to_port[(dst.dpid, dst.port_no)] = (src.dpid, src.port_no)
self.host_or_switch[(src.dpid, src.port_no)] = 1
self.host_or_switch[(dst.dpid, dst.port_no)] = 1
for host in host_list:
port = host.port
self.link_to_port[(port.dpid, port.port_no)] = (host.mac, host.ipv4)
self.host_or_switch[(port.dpid, port.port_no)] = 2
#packein message handler (it is useless in this function)
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def packetin_handler(self, ev):
# print ev.msg
msg = ev.msg
pkt = packet.Packet(msg.data)
# print pkt.get_protocols
dpid = msg.datapath.id
port = msg.match['in_port']
self.get_topology(None)
events = [event.EventSwitchEnter,
event.EventSwitchLeave, event.EventPortAdd,
event.EventPortDelete, event.EventPortModify,
event.EventLinkAdd, event.EventLinkDelete]
#monitor the change in link information
@set_ev_cls(events)
def get_topology(self, ev):
self.create_map(get_switch(self.topology_api_app))
# print get_host(self.topology_api_app)
# print type(get_host(self.topology_api_app))
self.create_link_port(get_link(self.topology_api_app), get_host(self.topology_api_app))
# self.show_topology()
#some command line output typesetting
def show_topology(self):
i = 1
print ""
print ""
print ""
print "----------------" * 2, "physical topology", "----------------" * 6
for dpid in self.switch_port_table.keys():
print "switch%d ----------dpid---------- " % i,
for port_no in self.switch_port_table[dpid]:
print "-----------port %s-----------" % port_no,
print ""
print " ", "%11d" % dpid ,"%12s" % " ",
# # print self.switch_port_table[dpid]
try:
for port_no in self.switch_port_table[dpid]:
if self.host_or_switch[(dpid, port_no)] == 1:
print "%10s" % "switch", "%d" % self.link_to_port[(dpid, port_no)][0], " port %d" % self.link_to_port[(dpid, port_no)][1], " ",
elif self.host_or_switch[(dpid, port_no)] == 2:
print "%s" % "host", "mac: %s" % self.link_to_port[(dpid, port_no)][0],
else:
print "%28s" % "None"
print ""
print " ", "%23s" % " ",
for port_no in self.switch_port_table[dpid]:
if self.host_or_switch[(dpid, port_no)] == 2:
print " ipv4 :", self.link_to_port[(dpid, port_no)][1],
else:
print "%28s" % " ",
print
except Exception as error:
print "please input pingall in mininet and wait a momment until it's finished"
i = i + 1
print "------------------" * 8
print ""
print ""
print ""
细节点
这也是我调了半天的一个bug，使用hub.spawn与hub.sleep配合的函数，应该可以达到停几秒休息一次的作用，尝试很多无果，后来自己随便建了一个没有消息处理机制的函数进行测试，发现其却能正常运行。究其原因，后面原来是自己没有异常处理。异常处理很重要！！！
实验效果图
实验缺陷
对于不同的终端可能适配不一样，尽量放大到全屏看的比较直观，如果设备多了，这个显示依然是一片模糊，后期将加入一个做成json，做成web可视化
实验总结
这个程序有一大部分得感谢呈神的参考，还有其他部分也是自己对python的一些类似循环，字典的一些应用，懂得去debug，对python不会那么陌生。
