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我在这里有一个我正在尝试运行的链接状态路由协议的代码，但是由于某些愚蠢的原因，它给了我一个错误，说远程主机关闭了连接。我的代码采用三个参数，即路由器 ID、端口和包含相邻路由器节点及其成本和端口号的配置文件。

我使用的连接协议是 UDP，而不是 TCP。我似乎遇到的最大问题是代码仍然以某种方式不断产生输出（屏幕截图中的最后三行）。

这是我的输出截图：

输出截图

和我的代码：

    #!/usr/bin/python

import socket
import pickle
import sys
import random
from threading import Thread,Lock
import time
from collections import defaultdict


class Graph:
  def __init__(self):
    self.lock = Lock()
    self.nodes = set()
    self.edges = defaultdict(list)
    self.distances = {}

  def add_node(self, value):
    self.lock.acquire()
    try:
      self.nodes.add(value)
    finally:
      self.lock.release()

  def add_edge(self, from_node, to_node, distance):
    self.lock.acquire()
    try:
      self.edges[from_node].append(to_node)
      self.edges[to_node].append(from_node)
      self.distances[(from_node, to_node)] = distance
      self.distances[(to_node, from_node)] = distance
    finally:
      self.lock.release()


def dijkstra(graph, initial):
  visited = {initial: 0}
  path = {}

  nodes = set(graph.nodes)

  while nodes:
    min_node = None
    for node in nodes:
      if node in visited:
        if min_node is None:
          min_node = node
        elif visited[node] < visited[min_node]:
          min_node = node

    if min_node is None:
      break

    nodes.remove(min_node)
    current_weight = visited[min_node]

    for edge in graph.edges[min_node]:
      weight = current_weight + graph.distances[(min_node, edge)]
      if edge not in visited or weight < visited[edge]:
        visited[edge] = weight
        path[edge] = min_node

  return visited, path

def shortestPath(self,P,target):
  path = []
  while True:
    path.append(target)
    if target == self:
      break
    target = P[target]

  path.reverse()
  return path


def broadcast(s, self, neighbours_cost, neighbours_port):
  while True:
    seq = random.randint(0,10000)
    # seq = 200
    for i, v in enumerate(neighbours_port):
        value = {'from':self,'neighbours':neighbours_cost,'seq':seq}
        packet = pickle.dumps(value)
        s.sendto(packet, ('127.0.0.1',neighbours_port[v]))#v is its neighbours
        # print value['neighbours'][v]
        # print 'sent to %d' %(neighbours_port[v])
    time.sleep(1)


def rebroadcast(s, self, graph, port, neighbours_port, received_lsp):
  #gotta checks for incoming packet, and will rebroadcast while also adding more to the topology
  while True:
    rereceived = False
    # print 'waiting for lsp'
    packet, client = s.recvfrom(1024) #lsp doesn't go over 300
    message = pickle.loads(packet)
    broadcasted_neighbour = message['neighbours']
    source = message['from']

    #checks whether this is a message previously received or not
    if message['seq'] in received_lsp:
      rereceived = True

    #checks if lsp is from source
    if source != self and rereceived == False:
      # print message
      received_lsp.add(message['seq'])
      for i, v in enumerate(broadcasted_neighbour):
        graph.add_node(v)
        graph.add_edge(message['from'],v,broadcasted_neighbour[v])

      for i, v in enumerate(neighbours_port):
        if v != source:
          s.sendto(packet, ('127.0.0.1',neighbours_port[v]))
          # print 'rebroadcasted packet from %s' %(source)


def countShortest(self,graph,received_lsp):
  while True:
    time.sleep(30)
    visited, path = dijkstra(graph, self)
    for node in graph.nodes:
      string = ''
      route = shortestPath(self, path, node)
      for track in route:
        string = string+track
      if string != node:
        print 'least-cost path to node %s: %s and the cost is %.1f' %(node,string,round(visited[node],1))
    print ''
    received_lsp = set()#clears the previous 30 seconds worth of seq nums

#--------------------------------main is here----------------------------------
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

self = sys.argv[1]
port = int(sys.argv[2])
f = open(sys.argv[3],'r')
neighbours_cost = {}
neighbours_port = {}
received_lsp = set()
threads = []
num_of_neighbour = f.readline()
num_of_neighbour = int(num_of_neighbour)

host=''
s.bind((host,port))


graph = Graph()
graph.add_node(self)

for i in range (0,num_of_neighbour):
  read = f.readline()
  read = read.split()
  neighbours_cost[read[0]] = float(read[1])
  neighbours_port[read[0]] = int(read[2])
  graph.add_node(read[0])
  graph.add_edge(self, read[0], float(read[1]))

try:
  #broadcast thread
  print 'starting broadcast thread'
  t1 = Thread(target=broadcast, kwargs={'s':s,'self':self,'neighbours_cost':neighbours_cost,'neighbours_port':neighbours_port})
  t1.daemon = True
  #rebroadcast thread
  print 'starting rebroadcast thread'
  t2 = Thread(target=rebroadcast, kwargs={'s':s,'self':self,'graph':graph,'port':port,'neighbours_port':neighbours_port,'received_lsp':received_lsp})
  t2.daemon = True
  #dijkstra thread
  print 'starting dijkstra thread'
  t3 = Thread(target=countShortest, kwargs={'self':self,'graph':graph, 'received_lsp':received_lsp})
  t3.daemon = True
  threads.append(t1)
  threads.append(t2)
  threads.append(t3)
  t1.start()
  t2.start()
  t3.start()
  while True:
      i = 1
except KeyboardInterrupt:
  print 'keyboard interrupt triggered'
  s.close()
  sys.exit(1)
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