北邮计算机网络课程设计DNS服务器(共10页).doc

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1、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 = re

2、verse_map = key_record = 0client_wait = s.bind(,porttime_rest = 0request_general = print runningwhile 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 =

3、answer = list(msgprint Type:Remote Responseprint 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+re

4、quest1for 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 Requestprint ip and port:

5、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 = ma

6、keframe.make(re_ip0,msgs.sendto(zhen,(client,portelse:print need to ask remote serverkey_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(cl

7、ient# select authority DNS server as you wishs.sendto(msg,(10.3.9.4,53time_rest = time_rest+1try:if(time_rest = 50:print pay attentionprint #mydic.updateCache(print #the_dic = mydic.get_web_ip(time_rest = 0except:print not valid frequenceprint -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

8、 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.txtfor each_line in data:try:(ip,sitecopy = each_line.split( ,1(site,nothing = str(sitecopy.spl

9、it(n,1d_web_ipsite = ip,1d_ip_webip = siteexcept:print file errordata.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

10、 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

11、,with ip +add_frequen0 return add_frequen1else:update_dicweb_site = add,1print record for a new sitereturn 1def updateCache(:global update_dicm = update_dic.copy(t = threading.Thread(target = my_thread,kwargs = m print ready to update local cachet.start(t.join(def my_thread(*argu,*arg:frequence = re

12、main_dic = for each_key in arg:tmp = argeach_keyif(tmp1 not in frequence:frequence.append(tmp1if(tmp0 = 0.0.0.0:remain_diceach_key = 0.0.0.0print 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(

13、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,wfor each_key in new_dic:word = str(new_diceach_k

14、ey + + 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

15、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

16、 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_li

17、st0 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