北邮计算机网络课程设计DNS服务器.doc

北邮计算机网络课程设计DNS服务器1 环境操作系统随意，语言python2.7 2. 文件Socket.py 说明 完成缓存检测，确定是回应，还是转发，如果是回应，确定是本地回应还是外部应答转发import socketimport mydicimport charhandleimport makeframes = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)port = 53the_dic = mydic.get_web_ip()client_request = client_request_index = reverse_map = key_record = 0client_wait = s.bind(,port)time_rest = 0request_general = print runningwhile True: try: msg , (client,port) = s.recvfrom(1024) except: print Time out! continue request = request = list(msg) requre_web = charhandle.get_request(request12:) website = .join(requre_web) if(port = 53): answer = answer = list(msg) print Type:Remote Response print remote answer is: response_ip = msg-4+msg-3+msg-2+msg-1 char_ip = socket.inet_ntoa(response_ip) print website + has the ip : +char_ip fre = mydic.storeForUpdate(website,char_ip ) print with the frequence of + str(fre) #real_request = client_requestrequest0+request1 for each_client in client_wait: my_key = client_requestrequest0+request1+str(each_client) if client_request_index.get(my_key) != None : s.sendto(msg,client_request_indexmy_key) print Response to ip and Client port: print client_request_indexmy_key break else: print Type: Client Request print ip and port： print (client,port) # requre_web = charhandle.get_request(request12:) # website = .join(requre_web) print Request website:+website if(the_dic.get(website) != None): print Found in local cache: re_ip = the_dic.get(website) print re_ip fre = mydic.storeForUpdate(website) print re_ip0+ with frequence +str(fre) zhen = makeframe.make(re_ip0,msg) s.sendto(zhen,(client,port) else: print need to ask remote server key_record = key_record + 1 request_general = key_record client_requestrequest0+request1+str(client) = request_general client_request_indexrequest_general = (client,port) if client not in client_wait: client_wait.append(client) # select authority DNS server as you wish s.sendto(msg,(10.3.9.4,53) time_rest = time_rest+1 try: if(time_rest = 50): print pay attention print # mydic.updateCache() print # the_dic = mydic.get_web_ip() time_rest = 0 except: print not valid frequence print -s.close()Mydic.py 完成本地查询，LRU算法维护本地缓存，socket.py第97行的time_request值可以确定更新缓存的频率，可以直接输出在dnsrelay.txt内，但是为了方便观测变化，我输出到了dnsrelaycopy.txt里面，运行一段时间之后，可以去看看学习到的新条目import pickleimport osimport threadingA=d_web_ip = d_ip_web = update_dic = data = open(dnsrelay.txt)for each_line in data: try: (ip,sitecopy) = each_line.split( ,1) (site,nothing) = str(sitecopy).split(n,1) d_web_ipsite = ip,1 d_ip_webip = site except: print file errordata.close()try: with open(newdnsrelay.pickle,wb) as newdnsrelay_file: pickle.dump(d_web_ip,newdnsrelay_file)except IOError as err: print File error:+str(err)except pickle.PickleError as perr: print Pickling error:+str(perr)def get_web_ip(): with open(newdnsrelay.pickle,rb) as f: global update_dic update_dic = pickle.load(f) return update_dic.copy() return(None)def storeForUpdate(web_site, add = None): global update_dic if(update_dic.get(web_site) != None): add_frequen = update_dicweb_site add_frequen1 = add_frequen1 + 1 print web_site+ frequence incrase 1,with ip +add_frequen0 return add_frequen1 else: update_dicweb_site = add,1 print record for a new site return 1def updateCache(): global update_dic m = update_dic.copy() t = threading.Thread(target = my_thread,kwargs = m) print ready to update local cache t.start() t.join()def my_thread(*argu,*arg): frequence = remain_dic = for each_key in arg: tmp = argeach_key if(tmp1 not in frequence): frequence.append(tmp1) if(tmp0 = 0.0.0.0): remain_diceach_key = 0.0.0.0 print various frequence: for each in frequence: print have + str(each) for each_key in remain_dic: arg.pop(each_key)#enimilate ban i = 0 while(i 30): max_frequence = max(frequence) for each_key in arg: tmp = argeach_key if(tmp1 = max_frequence): remain_diceach_key = tmp0 i = i + 1 if(i = 30): break; frequence.remove(max_frequence) if(not frequence):#no more break; updateFile(remain_dic)def updateFile(new_dic): f = open(dnsrelaycopy.txt,w) for each_key in new_dic: word = str(new_diceach_key) + + str(each_key) f.write(word) f.write(n) new_diceach_key = new_diceach_key,0 try: with open(newdnsrelay.pickle,wb) as newdnsrelay_file: pickle.dump(new_dic,newdnsrelay_file) except IOError as err: print File error:+str(err) except pickle.PickleError as perr: print Pickling error:+str(perr) Makefram.py 成帧模块，形成对外围权威服务器的询问帧import socketdef make(re_ip,msg): tmp_list = for ch in msg: tmp_list.append(ch) tmp_list4:12 = x00,x01,x00,x01,x00,x00,x00,x00 tmp_list = tmp_list+xc0,x0c,x00,x01,x00,x01,x00,x00,x02,x58,x00,x04 dive_ip = socket.inet_aton(re_ip) ch_ip = for each_ch in dive_ip: ch_ip.append(each_ch) tmp_list = tmp_list + ch_ip re_msg = .join(tmp_list) return re_msgCharhandle.py 提取出报文中的urldef get_request(your_list): my_list = new_list = my_list.extend(your_list) re_list = thelen = ord(my_list0) try: while thelen != 0: new_list = new_list + my_list1:thelen+1 my_list0:thelen+1 = thelen = ord(my_list0) new_list.append(.) except IndexError: print bao