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IP屬地：湖北 上傳時間：2022-09-22 格式：DOCX 頁數(shù)：19 大?。?15.53KB 積分：30 舉報 版權(quán)申訴

1、姓名：# 學號：# 專業(yè)：計算機科學與技術(shù)簡單的路由程序設(shè)計實驗報告姓名：#學號：#專業(yè)：計算機科學與技術(shù)完成日期：2014/6/4目錄 TOC o 1-3 h z u HYPERLINK l _Toc389738459 實驗環(huán)境 PAGEREF _Toc389738459 h 3 HYPERLINK l _Toc389738460 簡單的路由程序設(shè)計 PAGEREF _Toc389738460 h 3 HYPERLINK l _Toc389738461 路由軟件應(yīng)該處理的主要內(nèi)容 PAGEREF _Toc389738461 h 3 HYPERLINK l _Toc389738462 程序運行

2、流程圖解 PAGEREF _Toc389738462 h 4 HYPERLINK l _Toc389738463 程序代碼詳解 PAGEREF _Toc389738463 h 6 HYPERLINK l _Toc389738464 路由表處理函數(shù)： PAGEREF _Toc389738464 h 6 HYPERLINK l _Toc389738465 初始化操作 PAGEREF _Toc389738465 h 8 HYPERLINK l _Toc389738466 路由表操作： PAGEREF _Toc389738466 h 9 HYPERLINK l _Toc389738467 數(shù)據(jù)報的捕獲

3、與轉(zhuǎn)發(fā) PAGEREF _Toc389738467 h 12 HYPERLINK l _Toc389738468 實驗結(jié)果 PAGEREF _Toc389738468 h 17 HYPERLINK l _Toc389738469 實驗總結(jié)與心得體會 PAGEREF _Toc389738469 h 18 HYPERLINK l _Toc389738470 實驗中遇到的困難 PAGEREF _Toc389738470 h 18 HYPERLINK l _Toc389738471 實驗心得 PAGEREF _Toc389738471 h 19實驗環(huán)境本實驗要求用VC編寫簡單路由程序，實現(xiàn)IP數(shù)據(jù)包的

4、轉(zhuǎn)發(fā)。在局域網(wǎng)中進行調(diào)試，實驗使用的以太網(wǎng)可以是共享式以太網(wǎng)也可以是交換式以太網(wǎng)。實驗環(huán)境如下圖所示。路由R1、R2運行自主編寫的路由程序，綁定雙IP，通過路由程序添加路由表，對接收的數(shù)據(jù)包進行分析和轉(zhuǎn)發(fā)，實現(xiàn)處于不同網(wǎng)絡(luò)中的主機I和II的相互通信。通信測試由ping命令執(zhí)行，可以通過tracer +IP地址 來追蹤數(shù)據(jù)包在網(wǎng)絡(luò)中的轉(zhuǎn)發(fā)路徑。簡單的路由程序設(shè)計路由軟件應(yīng)該處理的主要內(nèi)容編制一個較為完整的路由軟件相當復(fù)雜包含如下工作：為經(jīng)過的IP 數(shù)據(jù)報選擇路由：路由器基本功能，對接受的IP數(shù)據(jù)報提取目的IP地址，根據(jù)自己的路由表信息為該數(shù)據(jù)報選擇最優(yōu)的轉(zhuǎn)發(fā)路徑。處理IP 數(shù)據(jù)報的TTL域中的數(shù)

5、值，拋棄TTLnext=NULL;router_size+;return true;if(router_size=1) rc-next=new router_chart;memcpy(rc-next,addroute,sizeof(struct router_chart);rc-next-next=NULL;router_size+;return true;router_chart *temp;for(temp=rc;temp-next!=NULL;temp=temp-next)if(temp-desnet=addroute-desnet)&(temp-netmask=addroute-net

6、mask)return false;/重復(fù)添加temp-next=new router_chart;memcpy(temp-next,addroute,sizeof(struct router_chart);router_size+;temp-next-next=NULL;return true;-編輯路由表選項：BOOL edit_route(router_chart *rc,int choice,router_chart *editroute)if(router_size=0|choicerouter_size)return false;router_chart *temp;temp=rc

7、;if(choice=1)temp=rc-next;memcpy(rc,editroute,sizeof(struct router_chart);rc-next=temp;return true;for(int i=2;temp;temp=temp-next)if(i=choice)memcpy(temp-next,editroute,sizeof(struct router_chart);/*temp-desnet=editroute-desnet;temp-netmask=editroute-netmask;temp-NextHop=editroute-NextHop;*/return

8、true;return false;-刪除路由表選項：BOOL del_route(router_chart *rc,int choice)if(router_size=0|choicerouter_size)return false;router_chart *temp;temp=rc;if (choice=1)rc=rc-next;for(int i=2;temp;i+,temp=temp-next)if(i=choice)temp-next=temp-next-next;router_size-;return true;return false;/路由表中不存在所選項-匹配路由表選項：U

9、LONG match(router_chart *rc, ULONG desIP)ULONG N_Hop=-1;router_chart *temp;temp=rc;ULONG longest=0;for(;temp;temp=temp-next)if(temp-netmask&desIP)=temp-desnet)if(temp-netmask=longest)longest=temp-netmask;N_Hop=temp-NextHop;if(N_Hop=-1)return 0 xffffffff;/沒有匹配項elsereturn N_Hop;初始化操作獲得計算機上的設(shè)備列表，選擇一個設(shè)備

10、進行偵聽，利用虛假地址請求本地MAC地址。此為第二次實驗內(nèi)容，代碼相同，不再列出。添加默認路由，網(wǎng)絡(luò)和子網(wǎng)掩碼為本機所處的環(huán)境，下一跳步為“直接投遞”。/添加投遞本地的路由選項for(a=Dev_addr;a!=NULL;a=a-next)coutadding!addr-sa_family=AF_INET)/是否IP地址ULONG r_netmask,r_desnet,r_nexthop;r_netmask=IfInfo.IPMask;r_desnet=(IfInfo.IPAddrtest2)&IfInfo.IPMask;/網(wǎng)絡(luò)地址=IP地址&子網(wǎng)掩碼test2+;r_nexthop=0;/本

11、路由所在網(wǎng)絡(luò)，直接投遞數(shù)據(jù)報router_chart *rc_ini;rc_ini=new router_chart;rc_ini-netmask=r_netmask;rc_ini-desnet=r_desnet;rc_ini-NextHop=r_nexthop;if(add_route(rc,rc_ini)coutYou have successfully insert the first route item!n;foutrc.close();flush_rctxt(rc);/將數(shù)據(jù)緩沖到router_chart.txt文檔中foutrc.open(router_chart.txt,ios

12、:out|ios:app)；elsecoutError occurs in the initial router_chart insertion.n;pcap_freealldevs(alldevs);路由表操作：提示用戶是否要對路由表進行操作，可以進行的操作為増、刪、改。每次修改后會顯示路由表。char goon;router_chart *temprc;temprc=new router_chart;doint tempi=1;coutnext)couttempinetmask);t2=htonl(temprc-desnet);t3=htonl(temprc-NextHop);memcpy

13、(&addr_temp,&t1,4);coutinet_ntoa(addr_temp)t;memcpy(&addr_temp,&t2,4);coutinet_ntoa(addr_temp)tt;memcpy(&addr_temp,&t3,4);coutinet_ntoa(addr_temp)n;tempi+;coutDo you want to edit the router chart?(Y or y or yes,others for no)n;cout(a for add,e for edit,d for delete, others for quit)n;couteditrc;if(e

14、ditrc=a|editrc=e)ULONG NM,DN,NH;int edit;char cnm16,cdn16,cnh16;if(editrc=e)docoutedit;while(edit=router_size);docoutcnm;NM=(htonl)(inet_addr(cnm);while(NM=INADDR_NONE);docoutcdn;DN=(htonl)(inet_addr(cdn);while(DN=INADDR_NONE);docoutcnh;NH=(htonl)(inet_addr(cnh);while(NH=INADDR_NONE);router_chart *t

15、emprc2;temprc2=new router_chart;temprc2-desnet=DN;temprc2-netmask=NM;temprc2-NextHop=NH;in_addr addr_temp;if(editrc=a)if(add_route(rc,temprc2)t1=htonl(temprc2-netmask);t2=htonl(temprc2-desnet);t3=htonl(temprc2-NextHop);foutrcrouter_size:;memcpy(&addr_temp,&t1,4);foutrcinet_ntoa(addr_temp)t;memcpy(&a

16、ddr_temp,&t2,4);foutrcinet_ntoa(addr_temp)tt;memcpy(&addr_temp,&t3,4);foutrcinet_ntoa(addr_temp)n;coutCongraduation! You have just add a route item.;coutPlease check the router_chart.txtn;elsecoutError occurs in the addition!n;elseif(edit_route(rc,edit,temprc)foutrc.close();flush_rctxt(rc);foutrc.op

17、en(router_chart.txt,ios:out|ios:app);else coutError occurs in the edition!n;else if(editrc=d)int del;docoutdel;while(del=router_size);if(del_route(rc,del)foutrc.close();flush_rctxt(rc);foutrc.open(router_chart.txt,ios:out|ios:app);else coutError occurs in the deletion!n;coutgoon;while(goon=Y|goon=y)

18、;數(shù)據(jù)報的捕獲與轉(zhuǎn)發(fā)根據(jù)流程圖，首先篩選出目的IP不是本機IP，目的MAC是本機MAC的IP數(shù)據(jù)報，將其源MAC改為本機MAC,目的MAC 改為下一跳步MAC，TTL值減一，重新計算校驗和，然后整理數(shù)據(jù)報轉(zhuǎn)發(fā)出去。此操作為一個無限循環(huán)，一旦進入則不斷捕獲數(shù)據(jù)報并對符合條件的數(shù)據(jù)報進行操作。do/編譯過濾規(guī)則filter=ip;if(pcap_compile(IfInfo.adhandle,&fcode,filter,1,IfInfo.IPMask)0)coutFail to compile the filtering expression,please check your filtering

19、 expression syntax!n;cout*ERROR in opening interface!*endl;/設(shè)置過濾規(guī)則if(pcap_setfilter(IfInfo.adhandle,&fcode)0)coutFail to set the filter!n;cout*ERROR in opening interface!*endl;/*/pcap_rtn=pcap_next_ex(IfInfo.adhandle,&pkt_header,&pkt_data);IPPacket = (Data_t *)pkt_data; if(pcap_rtn=1) cout*Successfu

20、lly capturing data packet!*FrameHeader.FrameType)=0 x0800)&(memcmp(IPPacket-FrameHeader.DesMAC),IfInfo.MACAddr,6)=0)/00)/為IP 數(shù)據(jù)報u_char *SendIPPacket;int plen=pkt_header-len+sizeof(FrameHeader_t);SendIPPacket=new u_charplen;memcpy(SendIPPacket,pkt_data,plen);/ULONG len;ULONG next_hop;/請求的IP 和由ARP 獲得該

21、IP 的MAC地址UCHAR ReqMAC6;ULONG ReqIP;foutlog.open(routerlog.txt,ios:out|ios:app);foutrc.open(router_chart.txt,ios:out|ios:app);WORD RecvChecksum = IPPacket-IPHeader.Checksum;BYTE *desmac =(IPPacket-FrameHeader.DesMAC);BYTE *srcmac =(IPPacket-FrameHeader.SrcMAC);u_short frametype =(ntohs(IPPacket-Frame

22、Header.FrameType);int ttl =IPPacket-IPHeader.TTL;ULONG src_ip=ntohl(IPPacket-IPHeader.SrcIP);ULONG des_ip=ntohl(IPPacket-IPHeader.DstIP);if(des_ip!=IfInfo.IPAddr0&des_ip!=IfInfo.IPAddr1)/目的MAC地址為本地，但是目的IP不是本地coutntest!n;/SendIPPacket=(Data_t *)pkt_data;cout*Successfully recieved an IPPacket :;foutlo

23、gIPHeader.SrcIP;des_ipaddr.S_un.S_addr=IPPacket-IPHeader.DstIP;src_ip=inet_ntoa(src_ipaddr);des_ip=inet_ntoa(des_ipaddr);coutDesIP &src_ip&des_ipDesMAC ;foutlogDesIP &src_ip&des_ipDesMAC ;mac_out(srcmac);cout;foutlog;mac_out(desmac);if(ttl=0)coutnThe IPPacket has reached its due time(TTL=1), throwin

24、g!;foutlognThe IPPacket has reached its due time(TTLIPHeader.DstIP);des_ipaddr.S_un.S_addr=htonl(next_hop);des_ip=inet_ntoa(des_ipaddr);coutnnextHop: des_ipendl;couthexnext_hopdecendl;if(next_hop=0 xffffffff)/匹配失敗coutn*Failed to match any router chart item!;foutlogIPHeader.DstIP);coutn*Successully f

25、ind the match router chart item, the NextHop is: inet_ntoa(addr_temp) (Direct deliver!);foutlogn*Successully find the match router chart item, the NextHop is: inet_ntoa(addr_temp) (Direct deliver!);elseReqIP=next_hop;coutn*Successully find the match router chart item, the NextHop is: inet_ntoa(addr_

26、temp);foutlogn*Successully find the match router chart item, the NextHop is: inet_ntoa(addr_temp);int ip_addr=0;if(ReqIP&IfInfo.IPMask)=IfInfo.IPAddr1)ip_addr=1;int trycont=1;bool flag=false;/確認是否找到需要的ARP數(shù)據(jù)報while(true)/編譯過濾規(guī)則filter=arp;if(pcap_compile(IfInfo.adhandle,&fcode,filter,1,IfInfo.IPMask)0)

27、coutFail to compile the filtering expression,please check your filtering expression syntax!n;cout*ERROR in opening interface!*endl;/設(shè)置過濾規(guī)則if(pcap_setfilter(IfInfo.adhandle,&fcode)0)coutFail to set the filter!n;cout*ERROR in opening interface!*Operation)=0 x0002)/為ARP應(yīng)答報文if(ntohl(RecvARPFrame-SendIP)

28、=(ReqIP)/為請求的地址memcpy(ReqMAC,RecvARPFrame-SendHa,6);/獲得Mac地址flag=true;break;if(flag)break;addr_temp.S_un.S_addr=ntohl(ReqIP);coutn*ARP Request successed! ;foutlogn*ARP Request successed! ;coutnIP address:inet_ntoa(addr_temp);foutlognIP address:inet_ntoa(addr_temp);cout MAC address:;foutlogMAC addres

29、s:;mac_out(ReqMAC);coutn*endl;coutnDelivering the IPPackete:;foutlogFrameHeader.DesMAC,ReqMAC,6);memcpy(IPPacket-FrameHeader.SrcMAC,IfInfo.MACAddr,6);IPPacket-IPHeader.TTL-;/生存時間減1WORD ip0=MAKEWORD(IPPacket-IPHeader.Ver_HLen,IPPacket-IPHeader.TOS);WORD ip1=IPPacket-IPHeader.TotalLen;WORD ip2=IPPacke

30、t-IPHeader.ID;WORD ip3=IPPacket-IPHeader.Flag_Segment;WORD ip4=MAKEWORD(IPPacket-IPHeader.TTL,IPPacket-IPHeader.Protocol);WORD ip5=0;WORD ip6=HIWORD(IPPacket-IPHeader.SrcIP);WORD ip7=LOWORD(IPPacket-IPHeader.SrcIP);WORD ip8=HIWORD(IPPacket-IPHeader.DstIP);WORD ip9=LOWORD(IPPacket-IPHeader.DstIP);WOR

31、D IP10=ip0,ip1,ip2,ip3,ip4,ip5,ip6,ip7,ip8,ip9;/*校驗和函數(shù)*/WORD ReChecksum;unsigned long cksum=0;for(i=0;i16)+(cksum&0 xffff);cksum+=(cksum16);ReChecksum=cksum;IPPacket-IPHeader.Checksum=ReChecksum;/重新置校驗和/記錄轉(zhuǎn)發(fā)內(nèi)容/in_addr src_ipaddr,des_ipaddr;/char *src_ip,*des_ip;src_ipaddr.S_un.S_addr=IPPacket-IPHeader.SrcIP;des_ipaddr.S_un.S_addr=IPPacket-IPHeader.DstIP;src_ip=inet_n