SDN实验---Ryu的应用开发（六）网络拓扑时延探测
一：预备知识
SDN实验---Ryu的应用开发（五）网络拓扑发现
Ryu源码之模块功能分析
Ryu源码之拓扑发现原理分析
二：实验原理
网络时延探测应用利用了Ryu自带的Switches模块的数据，获取到了LLDP数据发送时的时间戳，然后和收到的时间戳进行相减，得到了LLDP数据包从控制器下发到交换机A，然后从交换机A到交换机B，再上报给控制器的时延T1，示例见图1的蓝色箭头。
同理反向的时延T2由绿色的箭头组成。
此外，控制器到交换机的往返时延由一个蓝色箭头和一个绿色箭头组成，此部分时延由echo报文测试，分别为Ta，Tb。最后链路的前向后向平均时延T=（T1+T2-Ta-Tb）/2。
三：时延探测代码实现
（一）拓扑发现模块（已修改）
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): #修改，只获取拓扑，不主动显示！！！ """ 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) 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))
（二）模块导入
from ryu.base import app_manager from ryu.base.app_manager import lookup_service_brick from ryu.ofproto import ofproto_v1_3 from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER,CONFIG_DISPATCHER,DEAD_DISPATCHER,HANDSHAKE_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.switches import Switches from ryu.topology.switches import LLDPPacket import time
（三）数据结构
ECHO_REQUEST_INTERVAL = 0.05 DELAY_DETECTING_PERIOD = 5 class DelayDetect(app_manager.RyuApp): OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self,*args,**kwargs): super(DelayDetect,self).__init__(*args,**kwargs) self.name = "delay" self.topology = lookup_service_brick("topology") #注意：我们使用lookup_service_brick加载模块实例时，对于我们自己定义的app,我们需要在类中定义self.name。 self.switches = lookup_service_brick("switches") #此外，最重要的是：我们启动本模块DelayDetect时，必须同时启动自定义的模块！！！ 比如：ryu-manager ./TopoDetect.py ./DelayDetect.py --verbose --observe-links self.dpid2switch = {} #或者直接为{}，也可以。下面_state_change_handler也会添加进去 self.dpid2echoDelay = {} #记录echo时延 self.src_sport_dst2Delay = {} #记录LLDP报文测量的时延。实际上可以直接更新，这里单独记录，为了单独展示 {”src_dpid-srt_port-dst_dpid“：delay} self.detector_thread = hub.spawn(self._detector)
（四）协程获取链路时延
def _detector(self): """ 协程实现伪并发，探测链路时延 """ while True: if self.topology == None: self.topology = lookup_service_brick("topology") if self.topology.net_flag: #print("------------------_detector------------------") self._send_echo_request() self.get_link_delay() if self.topology.net_flag: try: self.show_delay() self.topology.show_topology() #拓扑显示 except Exception as err: print("------------------Detect delay failure!!!------------------") hub.sleep(DELAY_DETECTING_PERIOD) #5秒一次
（五）获取Echo时延
def _send_echo_request(self): """ 发生echo报文到datapath """ for datapath in self.dpid2switch.values(): parser = datapath.ofproto_parser echo_req = parser.OFPEchoRequest(datapath,data=bytes("%.12f"%time.time(),encoding="utf8")) #获取当前时间 datapath.send_msg(echo_req) #重要！不要同时发送echo请求，因为它几乎同时会生成大量echo回复。 #在echo_reply_处理程序中处理echo reply时，会产生大量队列等待延迟。 hub.sleep(ECHO_REQUEST_INTERVAL) @set_ev_cls(ofp_event.EventOFPEchoReply,[MAIN_DISPATCHER,CONFIG_DISPATCHER,HANDSHAKE_DISPATCHER]) def echo_reply_handler(self,ev): """ 处理echo响应报文，获取控制器到交换机的链路往返时延 Controller | echo latency | `|‘ Switch """ now_timestamp = time.time() try: echo_delay = now_timestamp - eval(ev.msg.data) self.dpid2echoDelay[ev.msg.datapath.id] = echo_delay except: return
（六）获取LLDP时延
补充：前面我们通过lookup_service_brick("switches")，实例化了switches模块。详细见：https://www.cnblogs.com/ssyfj/p/14193150.html。该模块中通过协程实现了周期0.05s发送LLDP数据包。所以我们下面可以直接获取LLDP数据报。
@set_ev_cls(ofp_event.EventOFPPacketIn,MAIN_DISPATCHER) def packet_in_handler(self,ev): #处理到达的LLDP报文，从而获得LLDP时延 """ Controller | /|\ \|/ | Switch----->Switch """ msg = ev.msg try: src_dpid,src_outport = LLDPPacket.lldp_parse(msg.data) #获取两个相邻交换机的源交换机dpid和port_no(与目的交换机相连的端口) dst_dpid = msg.datapath.id #获取目的交换机（第二个），因为来到控制器的消息是由第二个（目的）交换机上传过来的 dst_inport = msg.match['in_port'] if self.switches is None: self.switches = lookup_service_brick("switches") #获取交换机模块实例 #获得key（Port类实例）和data（PortData类实例） for port in self.switches.ports.keys(): #开始获取对应交换机端口的发送时间戳 if src_dpid == port.dpid and src_outport == port.port_no: #匹配key port_data = self.switches.ports[port] #获取满足key条件的values值PortData实例，内部保存了发送LLDP报文时的timestamp信息 timestamp = port_data.timestamp if timestamp: delay = time.time() - timestamp self._save_delay_data(src=src_dpid,dst=dst_dpid,src_port=src_outport,lldpdealy=delay) except: return def _save_delay_data(self,src,dst,src_port,lldpdealy): key = "%s-%s-%s"%(src,src_port,dst) self.src_sport_dst2Delay[key] = lldpdealy
（七）根据LLDP和Echo时延，更新网络拓扑图中的权值信息
def get_link_delay(self): """ 更新图中的权值信息 """ print("--------------get_link_delay-----------") for src_sport_dst in self.src_sport_dst2Delay.keys(): src,sport,dst = tuple(map(eval,src_sport_dst.split("-"))) if src in self.dpid2echoDelay.keys() and dst in self.dpid2echoDelay.keys(): sid,did = self.topology.dpid2id[src],self.topology.dpid2id[dst] if self.topology.net_topo[sid][did] != 0: if self.topology.net_topo[sid][did][0] == sport: s_d_delay = self.src_sport_dst2Delay[src_sport_dst]-(self.dpid2echoDelay[src]+self.dpid2echoDelay[dst])/2; if s_d_delay < 0: #注意：可能出现单向计算时延导致最后小于0，这是不允许的。则不进行更新，使用上一次原始值 continue self.topology.net_topo[sid][did][1] = self.src_sport_dst2Delay[src_sport_dst]-(self.dpid2echoDelay[src]+self.dpid2echoDelay[dst])/2
（八）显示网络拓扑图和Echo、LLDP时延信息
@set_ev_cls(ofp_event.EventOFPStateChange,[MAIN_DISPATCHER, DEAD_DISPATCHER]) def _state_change_handler(self, ev): datapath = ev.datapath if ev.state == MAIN_DISPATCHER: if not datapath.id in self.dpid2switch: self.logger.debug('Register datapath: %016x', datapath.id) self.dpid2switch[datapath.id] = datapath elif ev.state == DEAD_DISPATCHER: if datapath.id in self.dpid2switch: self.logger.debug('Unregister datapath: %016x', datapath.id) del self.dpid2switch[datapath.id] if self.topology == None: self.topology = lookup_service_brick("topology") print("-----------------------_state_change_handler-----------------------") print(self.topology.show_topology()) print(self.switches) def show_delay(self): print("-----------------------show echo delay-----------------------") for key,val in self.dpid2echoDelay.items(): print("s%d----%.12f"%(key,val)) print("-----------------------show LLDP delay-----------------------") for key,val in self.src_sport_dst2Delay.items(): print("%s----%.12f"%(key,val))
（九）全部代码
from ryu.base import app_manager from ryu.base.app_manager import lookup_service_brick from ryu.ofproto import ofproto_v1_3 from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER,CONFIG_DISPATCHER,DEAD_DISPATCHER,HANDSHAKE_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.switches import Switches from ryu.topology.switches import LLDPPacket import time ECHO_REQUEST_INTERVAL = 0.05 DELAY_DETECTING_PERIOD = 5 class DelayDetect(app_manager.RyuApp): OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self,*args,**kwargs): super(DelayDetect,self).__init__(*args,**kwargs) self.name = "delay" self.topology = lookup_service_brick("topology") #注意：我们使用lookup_service_brick加载模块实例时，对于我们自己定义的app,我们需要在类中定义self.name。 self.switches = lookup_service_brick("switches") #此外，最重要的是：我们启动本模块DelayDetect时，必须同时启动自定义的模块！！！ 比如：ryu-manager ./TopoDetect.py ./DelayDetect.py --verbose --observe-links self.dpid2switch = {} #或者直接为{}，也可以。下面_state_change_handler也会添加进去 self.dpid2echoDelay = {} self.src_sport_dst2Delay = {} #记录LLDP报文测量的时延。实际上可以直接更新，这里单独记录，为了单独展示 {”src_dpid-srt_port-dst_dpid“：delay} self.detector_thread = hub.spawn(self._detector) def _detector(self): """ 协程实现伪并发，探测链路时延 """ while True: if self.topology == None: self.topology = lookup_service_brick("topology") if self.topology.net_flag: #print("------------------_detector------------------") self._send_echo_request() self.get_link_delay() if self.topology.net_flag: try: self.show_delay() self.topology.show_topology() except Exception as err: print("------------------Detect delay failure!!!------------------") hub.sleep(DELAY_DETECTING_PERIOD) #5秒一次 def get_link_delay(self): """ 更新图中的权值信息 """ #print("--------------get_link_delay-----------") for src_sport_dst in self.src_sport_dst2Delay.keys(): src,sport,dst = tuple(map(eval,src_sport_dst.split("-"))) if src in self.dpid2echoDelay.keys() and dst in self.dpid2echoDelay.keys(): sid,did = self.topology.dpid2id[src],self.topology.dpid2id[dst] if self.topology.net_topo[sid][did] != 0: if self.topology.net_topo[sid][did][0] == sport: s_d_delay = self.src_sport_dst2Delay[src_sport_dst]-(self.dpid2echoDelay[src]+self.dpid2echoDelay[dst])/2; if s_d_delay < 0: #注意：可能出现单向计算时延导致最后小于0，这是不允许的。则不进行更新，使用上一次原始值 continue self.topology.net_topo[sid][did][1] = self.src_sport_dst2Delay[src_sport_dst]-(self.dpid2echoDelay[src]+self.dpid2echoDelay[dst])/2 def _send_echo_request(self): """ 发生echo报文到datapath """ #print("==========_send_echo_request==============") #print(self.dpid2switch) for datapath in self.dpid2switch.values(): parser = datapath.ofproto_parser echo_req = parser.OFPEchoRequest(datapath,data=bytes("%.12f"%time.time(),encoding="utf8")) #获取当前时间 #print("==========_send_echo_request=========2=====") datapath.send_msg(echo_req) #重要！不要同时发送echo请求，因为它几乎同时会生成大量echo回复。 #在echo_reply_处理程序中处理echo reply时，会产生大量队列等待延迟。 hub.sleep(ECHO_REQUEST_INTERVAL) @set_ev_cls(ofp_event.EventOFPEchoReply,[MAIN_DISPATCHER,CONFIG_DISPATCHER,HANDSHAKE_DISPATCHER]) def echo_reply_handler(self,ev): """ 处理echo响应报文，获取控制器到交换机的链路往返时延 Controller | echo latency | `|‘ Switch """ #print("================================") #print(ev) #print("================================") now_timestamp = time.time() try: echo_delay = now_timestamp - eval(ev.msg.data) self.dpid2echoDelay[ev.msg.datapath.id] = echo_delay except: return @set_ev_cls(ofp_event.EventOFPPacketIn,MAIN_DISPATCHER) def packet_in_handler(self,ev): #处理到达的LLDP报文，从而获得LLDP时延 """ Controller | /|\ \|/ | Switch----->Switch """ msg = ev.msg try: src_dpid,src_outport = LLDPPacket.lldp_parse(msg.data) #获取两个相邻交换机的源交换机dpid和port_no(与目的交换机相连的端口) dst_dpid = msg.datapath.id #获取目的交换机（第二个），因为来到控制器的消息是由第二个（目的）交换机上传过来的 dst_inport = msg.match['in_port'] if self.switches is None: self.switches = lookup_service_brick("switches") #获取交换机模块实例 #获得key（Port类实例）和data（PortData类实例） for port in self.switches.ports.keys(): #开始获取对应交换机端口的发送时间戳 if src_dpid == port.dpid and src_outport == port.port_no: #匹配key port_data = self.switches.ports[port] #获取满足key条件的values值PortData实例，内部保存了发送LLDP报文时的timestamp信息 timestamp = port_data.timestamp if timestamp: delay = time.time() - timestamp self._save_delay_data(src=src_dpid,dst=dst_dpid,src_port=src_outport,lldpdealy=delay) except: return def _save_delay_data(self,src,dst,src_port,lldpdealy): key = "%s-%s-%s"%(src,src_port,dst) self.src_sport_dst2Delay[key] = lldpdealy @set_ev_cls(ofp_event.EventOFPStateChange,[MAIN_DISPATCHER, DEAD_DISPATCHER]) def _state_change_handler(self, ev): datapath = ev.datapath if ev.state == MAIN_DISPATCHER: if not datapath.id in self.dpid2switch: self.logger.debug('Register datapath: %016x', datapath.id) self.dpid2switch[datapath.id] = datapath elif ev.state == DEAD_DISPATCHER: if datapath.id in self.dpid2switch: self.logger.debug('Unregister datapath: %016x', datapath.id) del self.dpid2switch[datapath.id] if self.topology == None: self.topology = lookup_service_brick("topology") #print("-----------------------_state_change_handler-----------------------") #print(self.topology.show_topology()) #print(self.switches) def show_delay(self): #print("-----------------------show echo delay-----------------------") for key,val in self.dpid2echoDelay.items(): print("s%d----%.12f"%(key,val)) #print("-----------------------show LLDP delay-----------------------") for key,val in self.src_sport_dst2Delay.items(): print("%s----%.12f"%(key,val))
四：实验测试
回顾：拓扑代码和时延代码
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) 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))
from ryu.base import app_manager from ryu.base.app_manager import lookup_service_brick from ryu.ofproto import ofproto_v1_3 from ryu.controller import ofp_event from ryu.controller.handler import MAIN_DISPATCHER,CONFIG_DISPATCHER,DEAD_DISPATCHER,HANDSHAKE_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.switches import Switches from ryu.topology.switches import LLDPPacket import time ECHO_REQUEST_INTERVAL = 0.05 DELAY_DETECTING_PERIOD = 5 class DelayDetect(app_manager.RyuApp): OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION] def __init__(self,*args,**kwargs): super(DelayDetect,self).__init__(*args,**kwargs) self.name = "delay" self.topology = lookup_service_brick("topology") #注意：我们使用lookup_service_brick加载模块实例时，对于我们自己定义的app,我们需要在类中定义self.name。 self.switches = lookup_service_brick("switches") #此外，最重要的是：我们启动本模块DelayDetect时，必须同时启动自定义的模块！！！ 比如：ryu-manager ./TopoDetect.py ./DelayDetect.py --verbose --observe-links self.dpid2switch = {} #或者直接为{}，也可以。下面_state_change_handler也会添加进去 self.dpid2echoDelay = {} self.src_sport_dst2Delay = {} #记录LLDP报文测量的时延。实际上可以直接更新，这里单独记录，为了单独展示 {”src_dpid-srt_port-dst_dpid“：delay} self.detector_thread = hub.spawn(self._detector) def _detector(self): """ 协程实现伪并发，探测链路时延 """ while True: if self.topology == None: self.topology = lookup_service_brick("topology") if self.topology.net_flag: #print("------------------_detector------------------") self._send_echo_request() self.get_link_delay() if self.topology.net_flag: try: self.show_delay() self.topology.show_topology() except Exception as err: print("------------------Detect delay failure!!!------------------") hub.sleep(DELAY_DETECTING_PERIOD) #5秒一次 def get_link_delay(self): """ 更新图中的权值信息 """ #print("--------------get_link_delay-----------") for src_sport_dst in self.src_sport_dst2Delay.keys(): src,sport,dst = tuple(map(eval,src_sport_dst.split("-"))) if src in self.dpid2echoDelay.keys() and dst in self.dpid2echoDelay.keys(): sid,did = self.topology.dpid2id[src],self.topology.dpid2id[dst] if self.topology.net_topo[sid][did] != 0: if self.topology.net_topo[sid][did][0] == sport: s_d_delay = self.src_sport_dst2Delay[src_sport_dst]-(self.dpid2echoDelay[src]+self.dpid2echoDelay[dst])/2; if s_d_delay < 0: #注意：可能出现单向计算时延导致最后小于0，这是不允许的。则不进行更新，使用上一次原始值 continue self.topology.net_topo[sid][did][1] = self.src_sport_dst2Delay[src_sport_dst]-(self.dpid2echoDelay[src]+self.dpid2echoDelay[dst])/2 def _send_echo_request(self): """ 发生echo报文到datapath """ #print("==========_send_echo_request==============") #print(self.dpid2switch) for datapath in self.dpid2switch.values(): parser = datapath.ofproto_parser echo_req = parser.OFPEchoRequest(datapath,data=bytes("%.12f"%time.time(),encoding="utf8")) #获取当前时间 #print("==========_send_echo_request=========2=====") datapath.send_msg(echo_req) #重要！不要同时发送echo请求，因为它几乎同时会生成大量echo回复。 #在echo_reply_处理程序中处理echo reply时，会产生大量队列等待延迟。 hub.sleep(ECHO_REQUEST_INTERVAL) @set_ev_cls(ofp_event.EventOFPEchoReply,[MAIN_DISPATCHER,CONFIG_DISPATCHER,HANDSHAKE_DISPATCHER]) def echo_reply_handler(self,ev): """ 处理echo响应报文，获取控制器到交换机的链路往返时延 Controller | echo latency | `|‘ Switch """ #print("================================") #print(ev) #print("================================") now_timestamp = time.time() try: echo_delay = now_timestamp - eval(ev.msg.data) self.dpid2echoDelay[ev.msg.datapath.id] = echo_delay except: return @set_ev_cls(ofp_event.EventOFPPacketIn,MAIN_DISPATCHER) def packet_in_handler(self,ev): #处理到达的LLDP报文，从而获得LLDP时延 """ Controller | /|\ \|/ | Switch----->Switch """ msg = ev.msg try: src_dpid,src_outport = LLDPPacket.lldp_parse(msg.data) #获取两个相邻交换机的源交换机dpid和port_no(与目的交换机相连的端口) dst_dpid = msg.datapath.id #获取目的交换机（第二个），因为来到控制器的消息是由第二个（目的）交换机上传过来的 dst_inport = msg.match['in_port'] if self.switches is None: self.switches = lookup_service_brick("switches") #获取交换机模块实例 #获得key（Port类实例）和data（PortData类实例） for port in self.switches.ports.keys(): #开始获取对应交换机端口的发送时间戳 if src_dpid == port.dpid and src_outport == port.port_no: #匹配key port_data = self.switches.ports[port] #获取满足key条件的values值PortData实例，内部保存了发送LLDP报文时的timestamp信息 timestamp = port_data.timestamp if timestamp: delay = time.time() - timestamp self._save_delay_data(src=src_dpid,dst=dst_dpid,src_port=src_outport,lldpdealy=delay) except: return def _save_delay_data(self,src,dst,src_port,lldpdealy): key = "%s-%s-%s"%(src,src_port,dst) self.src_sport_dst2Delay[key] = lldpdealy @set_ev_cls(ofp_event.EventOFPStateChange,[MAIN_DISPATCHER, DEAD_DISPATCHER]) def _state_change_handler(self, ev): datapath = ev.datapath if ev.state == MAIN_DISPATCHER: if not datapath.id in self.dpid2switch: self.logger.debug('Register datapath: %016x', datapath.id) self.dpid2switch[datapath.id] = datapath elif ev.state == DEAD_DISPATCHER: if datapath.id in self.dpid2switch: self.logger.debug('Unregister datapath: %016x', datapath.id) del self.dpid2switch[datapath.id] if self.topology == None: self.topology = lookup_service_brick("topology") #print("-----------------------_state_change_handler-----------------------") #print(self.topology.show_topology()) #print(self.switches) def show_delay(self): #print("-----------------------show echo delay-----------------------") for key,val in self.dpid2echoDelay.items(): print("s%d----%.12f"%(key,val)) #print("-----------------------show LLDP delay-----------------------") for key,val in self.src_sport_dst2Delay.items(): print("%s----%.12f"%(key,val))
（一）启动Ryu
ryu-manager ./TopoDetect.py ./DelayDetect.py --verbose --observe-links
（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
