一：實驗簡介
（一）網絡拓撲信息：
其中1,2,3表示該交換機對應的端口號！！！
（二）用鄰接矩陣展示
其中左側列S1,S2,S3,S4表示出節點，----->，上面S1,S2,S3,S4表示入節點。
（m,0），m表示出節點的端口--->入節點，0暫時表示兩個節點之間的時延信息！
（三）主機信息展示
二：代碼實現
（一）導入模塊
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數據路徑的狀態 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 #需要設置線程鎖
（二）數據結構
DELAY_MONITOR_PERIOD = 5
LOCK = threading.RLock() #實現線程鎖
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 #用於保持對象本身，后面get_switch等方法需要（我們也可以直接傳入self） self.link_list = None #保存所有的link信息，由get_link獲得 self.switch_list = None #保存所有的switch信息，由get_switch獲得 self.host_list = None #保存所有的host信息，由get_host獲得 self.dpid2id = {} #獲取交換機dpid,以及自定義id--->{dpid:id} self.id2dpid = {} #對應上面的self.dpid2id,翻轉即可，因為我們使用id進行建立鄰接矩陣，這兩個結構方便查找 self.dpid2switch = {} #保存dpid和對應的交換機全部信息---->通過矩陣獲得id,然后獲得dpid,最后獲得交換機對象信息 self.ip2host = {} #根據ip，保存主機對象信息--->{ip:host} self.ip2switch = {} #根據ip,獲取當前主機是連接到哪個交換機--->{ip:dpid} self.net_size = 0 #記錄交換機個數（網絡拓撲大小） self.net_topo = [] #用於保存鄰接矩陣 self.net_flag = False #標識：用於表示拓撲網絡拓撲self.net_topo是否已經更新完成
self.net_arrived = 0 #標識：用於表示網絡中交換機消息到達，每當一個交換機到達以后，我們設置+1
self.monitor_thread = hub.spawn(self._monitor) #協程實現定時檢測網絡拓撲
（三）實現基本openflow消息處理
@set_ev_cls(ofp_event.EventOFPSwitchFeatures,CONFIG_DISPATCHER) def switch_feature_handle(self,ev): """ datapath中有配置消息到達 """
LOCK.acquire()
self.net_arrived += 1 #表示有1個交換機到達
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：對於packet_in消息，我們沒有處理，所以整個網絡（交換機之間的鏈路）是無法工作通信的，
但是各個交換機可以與控制器通信（switch_feature_handle實現），主機也可以和邊緣交換機通信，
所以控制器可以獲取網絡拓撲信息！！！
（四）實現拓撲發現功能
def _monitor(self): """ 協程實現偽並發，探測拓撲狀態 """ while True: #print("------------------_monitor") self._host_add_handler(None) #主機單獨提取處理 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): #主機信息單獨處理，不屬於網絡拓撲 self.host_list = get_host(self.topology_api_app) #3.需要使用pingall,主機通過與邊緣交換機連接，才能告訴控制器 #獲取主機信息字典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") #獲取所有的交換機、鏈路 self.switch_list = get_switch(self.topology_api_app) #1.只要交換機與控制器聯通，就可以獲取 self.link_list = get_link(self.topology_api_app) #2.在ryu啟動時，加上--observe-links即可用於拓撲發現 #獲取交換機字典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 #根據鏈路信息，開始獲取拓撲信息 self.net_size = len(self.id2dpid) #表示網絡中交換機個數 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：這里0表示存在鏈路，后面可以修改為時延 self.net_topo[did][sid] = [dst_port,0] #注意：修改為列表，不要用元組，元組無法修改，我們后面要修改時延 self.net_flag = True #表示網絡拓撲創建成功
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）全部代碼
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數據路徑的狀態 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): """ 協程實現偽並發，探測拓撲狀態 """ while True: #print("------------------_monitor") self._host_add_handler(None) #主機單獨提取處理 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中有配置消息到達 """ #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): #主機信息單獨處理，不屬於網絡拓撲 self.host_list = get_host(self.topology_api_app) #3.需要使用pingall,主機通過與邊緣交換機連接，才能告訴控制器 #獲取主機信息字典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") #獲取所有的交換機、鏈路 self.switch_list = get_switch(self.topology_api_app) #1.只要交換機與控制器聯通，就可以獲取 self.link_list = get_link(self.topology_api_app) #2.在ryu啟動時，加上--observe-links即可用於拓撲發現 #獲取交換機字典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 #根據鏈路信息，開始獲取拓撲信息 self.net_size = len(self.id2dpid) #表示網絡中交換機個數 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：這里0表示存在鏈路，后面可以修改為時延 self.net_topo[did][sid] = [dst_port,0] #注意：修改為列表，不要用元組，元組無法修改，我們后面要修改時延 self.net_flag = True #表示網絡拓撲創建成功 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：實驗驗證
（一）啟動Ryu控制器
ryu-manager TopoDetect.py --verbose --observe-links
其中--observe-links用於拓撲發現，添加之后用於鏈路的信息獲取！！
（二）啟動mininet
sudo mn --topo=linear,4 --switch=ovsk --controller=remote --link=tc
注意：需要在mininet中使用pingall，才能使得交換機獲得host存在，從而使得控制器獲取host消息！！
（三）結果顯示
