北邮计算机网络课程设计DNS服务器(共10页).doc

精选优质文档-倾情为你奉上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 python2.72. 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_DGRAMport = 53the_dic = mydic.get_web_ip(client_request = client_request_index = reverse_map = key_record = 0client_wait = s.bind('',porttime_rest = 0request_general = ''print 'running'while True:try:msg , (client,port = s.recvfrom(1024except:print 'Time out! 'continuerequest = request = list(msgrequre_web = charhandle.get_request(request12:website = ''.join(requre_webif(port = 53:answer = answer = list(msgprint "Type:Remote Response"print "remote answer is: "response_ip = msg-4+msg-3+msg-2+msg-1char_ip = socket.inet_ntoa(response_ipprint website + ' has the ip : '+char_ipfre = mydic.storeForUpdate(website,char_ip print 'with the frequence of '+ str(fre#real_request = client_requestrequest0+request1for 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_keyprint "Response to ip and Client port:"print client_request_indexmy_keybreakelse:print "Type: Client Request"print "ip and port:"print (client,port# requre_web = charhandle.get_request(request12:# website = ''.join(requre_webprint "Request website:"+websiteif(the_dic.get(website != None:print "Found in local cache:"re_ip = the_dic.get(websiteprint re_ipfre = mydic.storeForUpdate(websiteprint re_ip0+' with frequence '+str(frezhen = makeframe.make(re_ip0,msgs.sendto(zhen,(client,portelse:print "need to ask remote server"key_record = key_record + 1request_general = key_recordclient_requestrequest0+request1+str(client = request_generalclient_request_indexrequest_general = (client,portif client not in client_wait:client_wait.append(client# select authority DNS server as you wishs.sendto(msg,('10.3.9.4',53time_rest = time_rest+1try:if(time_rest = 50:print 'pay attention'print '#'mydic.updateCache(print '#'the_dic = mydic.get_web_ip(time_rest = 0except: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',1d_web_ipsite = ip,1d_ip_webip = siteexcept:print 'file error'data.close(try:with open('newdnsrelay.pickle','wb' as newdnsrelay_file:pickle.dump(d_web_ip,newdnsrelay_fileexcept IOError as err:print 'File error:'+str(errexcept pickle.PickleError as perr:print 'Pickling error:'+str(perrdef get_web_ip(:with open('newdnsrelay.pickle','rb' as f:global update_dicupdate_dic = pickle.load(freturn update_dic.copy(return(Nonedef storeForUpdate(web_site, add = None:global update_dicif(update_dic.get(web_site != None:add_frequen = update_dicweb_siteadd_frequen1 = add_frequen1 + 1print web_site+' frequence incrase 1,with ip '+add_frequen0 return add_frequen1else:update_dicweb_site = add,1print 'record for a new site'return 1def updateCache(:global update_dicm = 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_keyif(tmp1 not in frequence:frequence.append(tmp1if(tmp0 = '0.0.0.0':remain_diceach_key = '0.0.0.0'print 'various frequence:'for each in frequence:print 'have '+ str(eachfor each_key in remain_dic:arg.pop(each_key#enimilate bani = 0while(i < 30:max_frequence = max(frequencefor each_key in arg:tmp = argeach_keyif(tmp1 = max_frequence:remain_diceach_key = tmp0i = i + 1if(i = 30:break;frequence.remove(max_frequenceif(not frequence:#no morebreak;updateFile(remain_dicdef updateFile(new_dic:f = open('dnsrelaycopy.txt','w'for each_key in new_dic:word = str(new_diceach_key + ' ' + str(each_key f.write(wordf.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 socket def 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_msg Charhandle.py 提取出报文中的 url def 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 wen ge shi bu dui" new_list.pop( return new_list 原始的 dnsrelay.txt 老师给出了，自己去弄，把四个 py 文件放一个目录下，再放一个 dnsrelay.txt 然后，用 python shell 打开 socket.py 从 python shell 运行，或者直接 F5，记得 把本地 dns 手动指向本机。 P.S：本人亲测，蒋老师没用过 python，从头到尾就是我讲他听，从不为难我，我说有 个 LRU 算法，他还说我做的好！ 如果有不懂的 联系作者： 学妹优先 专心-专注-专业