SDN实验---Ryu的应用开发（五）网络拓扑发现
一：实验简介
（一）网络拓扑信息：
其中1,2,3表示该交换机对应的端口号！！！
（二）用邻接矩阵展示
其中左侧列S1,S2,S3,S4表示出节点，----->，上面S1,S2,S3,S4表示入节点。
（m,0），m表示出节点的端口--->入节点，0暂时表示两个节点之间的时延信息！
（三）主机信息展示
二：代码实现
（一）导入模块
from ryu.base import app_manager from ryu.ofproto import ofproto_v1_3 from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER,CONFIG_DISPATCHER,DEAD_DISPATCHER #只是表示datapath数据路径的状态 from ryu.controller.handler import set_ev_cls from ryu.lib import hub from ryu.lib.packet import packet,ethernet from ryu.topology import event,switches from ryu.topology.api import get_switch,get_link,get_host
import threading #需要设置线程锁
（二）数据结构
DELAY_MONITOR_PERIOD = 5
LOCK = threading.RLock() #实现线程锁
class TopoDetect(app_manager.RyuApp): OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self,*args,**kwargs): super(TopoDetect,self).__init__(*args,**kwargs) self.topology_api_app = self #用于保持对象本身，后面get_switch等方法需要（我们也可以直接传入self） self.link_list = None #保存所有的link信息，由get_link获得 self.switch_list = None #保存所有的switch信息，由get_switch获得 self.host_list = None #保存所有的host信息，由get_host获得 self.dpid2id = {} #获取交换机dpid,以及自定义id--->{dpid:id} self.id2dpid = {} #对应上面的self.dpid2id,翻转即可，因为我们使用id进行建立邻接矩阵，这两个结构方便查找 self.dpid2switch = {} #保存dpid和对应的交换机全部信息---->通过矩阵获得id,然后获得dpid,最后获得交换机对象信息 self.ip2host = {} #根据ip，保存主机对象信息--->{ip:host} self.ip2switch = {} #根据ip,获取当前主机是连接到哪个交换机--->{ip:dpid} self.net_size = 0 #记录交换机个数（网络拓扑大小） self.net_topo = [] #用于保存邻接矩阵 self.net_flag = False #标识：用于表示拓扑网络拓扑self.net_topo是否已经更新完成
self.net_arrived = 0 #标识：用于表示网络中交换机消息到达，每当一个交换机到达以后，我们设置+1
self.monitor_thread = hub.spawn(self._monitor) #协程实现定时检测网络拓扑
（三）实现基本openflow消息处理
@set_ev_cls(ofp_event.EventOFPSwitchFeatures,CONFIG_DISPATCHER) def switch_feature_handle(self,ev): """ datapath中有配置消息到达 """
LOCK.acquire()
self.net_arrived += 1 #表示有1个交换机到达
LOCK.release() #print("------XXXXXXXXXXX------%d------XXXXXXXXXXX------------switch_feature_handle"%self.net_arrived) msg = ev.msg datapath = msg.datapath ofproto = datapath.ofproto ofp_parser = datapath.ofproto_parser match = ofp_parser.OFPMatch() actions = [ofp_parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,ofproto.OFPCML_NO_BUFFER)] self.add_flow(datapath=datapath,priority=0,match=match,actions=actions,extra_info="config infomation arrived!!") def add_flow(self,datapath,priority,match,actions,idle_timeout=0,hard_timeout=0,extra_info=None): #print("------------------add_flow:") if extra_info != None: print(extra_info) ofproto = datapath.ofproto ofp_parser = datapath.ofproto_parser inst = [ofp_parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,actions)] mod = ofp_parser.OFPFlowMod(datapath=datapath,priority=priority, idle_timeout=idle_timeout, hard_timeout=hard_timeout, match=match,instructions=inst) datapath.send_msg(mod); @set_ev_cls(ofp_event.EventOFPPacketIn,MAIN_DISPATCHER) def packet_in_handler(self,ev): #print("------------------packet_in_handler") msg = ev.msg datapath = msg.datapath ofproto = datapath.ofproto ofp_parser = datapath.ofproto_parser dpid = datapath.id in_port = msg.match['in_port'] pkt = packet.Packet(msg.data) eth_pkt = pkt.get_protocol(ethernet.ethernet) dst = eth_pkt.dst src = eth_pkt.src #self.logger.info("------------------Controller %s get packet, Mac address from: %s send to: %s , send from datapath: %s,in port is: %s" # ,dpid,src,dst,dpid,in_port) #self.get_topology(None)
注意：对于packet_in消息，我们没有处理，所以整个网络（交换机之间的链路）是无法工作通信的，
但是各个交换机可以与控制器通信（switch_feature_handle实现），主机也可以和边缘交换机通信，
所以控制器可以获取网络拓扑信息！！！
（四）实现拓扑发现功能
def _monitor(self): """ 协程实现伪并发，探测拓扑状态 """ while True: #print("------------------_monitor") self._host_add_handler(None) #主机单独提取处理 self.get_topology(None) if self.net_flag: try: self.show_topology() except Exception as err: print("Please use cmd: pingall to detect topology and wait a moment") hub.sleep(DELAY_MONITOR_PERIOD) #5秒一次
@set_ev_cls([event.EventHostAdd]) def _host_add_handler(self,ev): #主机信息单独处理，不属于网络拓扑 self.host_list = get_host(self.topology_api_app) #3.需要使用pingall,主机通过与边缘交换机连接，才能告诉控制器 #获取主机信息字典ip2host{ipv4:host object} ip2switch{ipv4:dpid} for i,host in enumerate(self.host_list): self.ip2switch["%s"%host.ipv4] = host.port.dpid self.ip2host["%s"%host.ipv4] = host events = [event.EventSwitchEnter, event.EventSwitchLeave, event.EventSwitchReconnected, event.EventPortAdd, event.EventPortDelete, event.EventPortModify, event.EventLinkAdd, event.EventLinkDelete] @set_ev_cls(events) def get_topology(self,ev): if not self.net_arrived: return
LOCK.acquire()
self.net_arrived -= 1
if self.net_arrived < 0:
self.net_arrived = 0
LOCK.release()
self.net_flag = False self.net_topo = [] print("-----------------get_topology") #获取所有的交换机、链路 self.switch_list = get_switch(self.topology_api_app) #1.只要交换机与控制器联通，就可以获取 self.link_list = get_link(self.topology_api_app) #2.在ryu启动时，加上--observe-links即可用于拓扑发现 #获取交换机字典id2dpid{id:dpid} dpid2switch{dpid:switch object} for i,switch in enumerate(self.switch_list): self.id2dpid[i] = switch.dp.id self.dpid2id[switch.dp.id] = i self.dpid2switch[switch.dp.id] = switch #根据链路信息，开始获取拓扑信息 self.net_size = len(self.id2dpid) #表示网络中交换机个数 for i in range(self.net_size): self.net_topo.append([0]*self.net_size) for link in self.link_list: src_dpid = link.src.dpid src_port = link.src.port_no dst_dpid = link.dst.dpid dst_port = link.dst.port_no try: sid = self.dpid2id[src_dpid] did = self.dpid2id[dst_dpid] except KeyError as e: print("--------------Error:get KeyError with link infomation(%s)"%e) return self.net_topo[sid][did] = [src_port,0] #注意：这里0表示存在链路，后面可以修改为时延 self.net_topo[did][sid] = [dst_port,0] #注意：修改为列表，不要用元组，元组无法修改，我们后面要修改时延 self.net_flag = True #表示网络拓扑创建成功
def show_topology(self): print("-----------------show_topology") print("----------switch network----------") line_info = " " for i in range(self.net_size): line_info+=" s%-5d "%self.id2dpid[i] print(line_info) for i in range(self.net_size): line_info = "s%d "%self.id2dpid[i] for j in range(self.net_size): if self.net_topo[i][j] == 0: line_info+="%-22d"%0 else: line_info+="(%d,%.12f) "%tuple(self.net_topo[i][j]) print(line_info) print("----------host 2 switch----------") for key,val in self.ip2switch.items(): print("%s---s%d"%(key,val))
（五）全部代码
from ryu.base import app_manager from ryu.ofproto import ofproto_v1_3 from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER,CONFIG_DISPATCHER,DEAD_DISPATCHER #只是表示datapath数据路径的状态 from ryu.controller.handler import set_ev_cls from ryu.lib import hub from ryu.lib.packet import packet,ethernet from ryu.topology import event,switches from ryu.topology.api import get_switch,get_link,get_host import threading,time,random DELAY_MONITOR_PERIOD = 5 class TopoDetect(app_manager.RyuApp): OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self,*args,**kwargs): super(TopoDetect,self).__init__(*args,**kwargs) self.topology_api_app = self self.name = "topology" self.link_list = None self.switch_list = None self.host_list = None self.dpid2id = {} self.id2dpid = {} self.dpid2switch = {} self.ip2host = {} self.ip2switch = {} self.net_size = 0 self.net_topo = [] self.net_flag = False self.net_arrived = 0 self.monitor_thread = hub.spawn(self._monitor) def _monitor(self): """ 协程实现伪并发，探测拓扑状态 """ while True: #print("------------------_monitor") self._host_add_handler(None) #主机单独提取处理 self.get_topology(None) if self.net_flag: try: self.show_topology() except Exception as err: print("Please use cmd: pingall to detect topology and wait a moment") hub.sleep(DELAY_MONITOR_PERIOD) #5秒一次 @set_ev_cls(ofp_event.EventOFPSwitchFeatures,CONFIG_DISPATCHER) def switch_feature_handle(self,ev): """ datapath中有配置消息到达 """ #print("------XXXXXXXXXXX------%d------XXXXXXXXXXX------------switch_feature_handle"%self.net_arrived) #print("----%s----------",ev.msg) msg = ev.msg datapath = msg.datapath ofproto = datapath.ofproto ofp_parser = datapath.ofproto_parser match = ofp_parser.OFPMatch() actions = [ofp_parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,ofproto.OFPCML_NO_BUFFER)] self.add_flow(datapath=datapath,priority=0,match=match,actions=actions,extra_info="config infomation arrived!!") def add_flow(self,datapath,priority,match,actions,idle_timeout=0,hard_timeout=0,extra_info=None): #print("------------------add_flow:") if extra_info != None: print(extra_info) ofproto = datapath.ofproto ofp_parser = datapath.ofproto_parser inst = [ofp_parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,actions)] mod = ofp_parser.OFPFlowMod(datapath=datapath,priority=priority, idle_timeout=idle_timeout, hard_timeout=hard_timeout, match=match,instructions=inst) datapath.send_msg(mod); @set_ev_cls(ofp_event.EventOFPPacketIn,MAIN_DISPATCHER) def packet_in_handler(self,ev): #print("------------------packet_in_handler") msg = ev.msg datapath = msg.datapath ofproto = datapath.ofproto ofp_parser = datapath.ofproto_parser dpid = datapath.id in_port = msg.match['in_port'] pkt = packet.Packet(msg.data) eth_pkt = pkt.get_protocol(ethernet.ethernet) dst = eth_pkt.dst src = eth_pkt.src #self.logger.info("------------------Controller %s get packet, Mac address from: %s send to: %s , send from datapath: %s,in port is: %s" # ,dpid,src,dst,dpid,in_port) self.get_topology(None) @set_ev_cls([event.EventHostAdd]) def _host_add_handler(self,ev): #主机信息单独处理，不属于网络拓扑 self.host_list = get_host(self.topology_api_app) #3.需要使用pingall,主机通过与边缘交换机连接，才能告诉控制器 #获取主机信息字典ip2host{ipv4:host object} ip2switch{ipv4:dpid} for i,host in enumerate(self.host_list): self.ip2switch["%s"%host.ipv4] = host.port.dpid self.ip2host["%s"%host.ipv4] = host events = [event.EventSwitchEnter, event.EventSwitchLeave, event.EventSwitchReconnected, event.EventPortAdd, event.EventPortDelete, event.EventPortModify, event.EventLinkAdd, event.EventLinkDelete] @set_ev_cls(events) def get_topology(self,ev): #print("------+++++++++++------%d------+++++++++++------------get_topology"%self.net_arrived) self.net_flag = False self.net_topo = [] #print("-----------------get_topology") #获取所有的交换机、链路 self.switch_list = get_switch(self.topology_api_app) #1.只要交换机与控制器联通，就可以获取 self.link_list = get_link(self.topology_api_app) #2.在ryu启动时，加上--observe-links即可用于拓扑发现 #获取交换机字典id2dpid{id:dpid} dpid2switch{dpid:switch object} for i,switch in enumerate(self.switch_list): self.id2dpid[i] = switch.dp.id self.dpid2id[switch.dp.id] = i self.dpid2switch[switch.dp.id] = switch #根据链路信息，开始获取拓扑信息 self.net_size = len(self.id2dpid) #表示网络中交换机个数 for i in range(self.net_size): self.net_topo.append([0]*self.net_size) for link in self.link_list: src_dpid = link.src.dpid src_port = link.src.port_no dst_dpid = link.dst.dpid dst_port = link.dst.port_no try: sid = self.dpid2id[src_dpid] did = self.dpid2id[dst_dpid] except KeyError as e: #print("--------------Error:get KeyError with link infomation(%s)"%e) return self.net_topo[sid][did] = [src_port,0] #注意：这里0表示存在链路，后面可以修改为时延 self.net_topo[did][sid] = [dst_port,0] #注意：修改为列表，不要用元组，元组无法修改，我们后面要修改时延 self.net_flag = True #表示网络拓扑创建成功 def show_topology(self): print("-----------------show_topology") print("----------switch network----------") line_info = " " for i in range(self.net_size): line_info+=" s%-5d "%self.id2dpid[i] print(line_info) for i in range(self.net_size): line_info = "s%d "%self.id2dpid[i] for j in range(self.net_size): if self.net_topo[i][j] == 0: line_info+="%-22d"%0 else: line_info+="(%d,%.12f) "%tuple(self.net_topo[i][j]) print(line_info) print("----------host 2 switch----------") for key,val in self.ip2switch.items(): print("%s---s%d"%(key,val))
三：实验验证
（一）启动Ryu控制器
ryu-manager TopoDetect.py --verbose --observe-links
其中--observe-links用于拓扑发现，添加之后用于链路的信息获取！！
（二）启动mininet
sudo mn --topo=linear,4 --switch=ovsk --controller=remote --link=tc
注意：需要在mininet中使用pingall，才能使得交换机获得host存在，从而使得控制器获取host消息！！
（三）结果显示
