TCP协议学习记录 (三) Ping程序 RR选项 记录路由hop

一开始想直接在上个程序改,自己构造IP包头,但后来发现不行,微软不让干了,所以后来选用libcap库来收发包

代码写的很乱..

 #pragma pack(4)

 #define  ECHO_REQUEST       8
 #define  DATASIZE           65500
 #define  PACKETSIZE         65535
 #define  IPCOUNT            9
 #define  MACSIZE            6
 #define  OPTION_RR          7

 struct ethhdr
 {
     char  mac_dst[MACSIZE];
     char  mac_src[MACSIZE];

     unsigned short eth_protocol;
     char  eth_data[DATASIZE];
 };

 struct iphdr
 {
     unsigned char  ip_hdr_len : ; //包头长度
     unsigned char  ip_version : ; //版本
     unsigned char  ip_tos;

     unsigned short ip_length;  //总长度
     unsigned short ip_identify;//标识
     unsigned short ip_offset;//片偏移
     unsigned char  ip_ttl;
     unsigned char  ip_protocol;
     unsigned short ip_cksum;

     struct in_addr ip_src; //源地址
     struct in_addr ip_dst; //目的地址

     unsigned char  ip_code;
     unsigned char  ip_len;
     unsigned char  ip_ptr;

     struct in_addr ip_router[IPCOUNT];

     char  ip_data[DATASIZE];
 };

 struct icmphdr
 {
     unsigned char  icmp_type; //8位类型
     unsigned char  icmp_code; //8位代码
     unsigned short icmp_cksum; //16位的校验和

     unsigned short icmp_identify;
     unsigned short icmp_seq;

     LONGLONG       icmp_timestamp;
     char           icmp_data[DATASIZE];
 };

 bool ping_rr(char * target,int payload,int count)
 {
     WSADATA wsaData;
     WSAStartup(MAKEWORD(, ), &wsaData);

     if(payload > DATASIZE)
     {
         printf("发送的字节数有错误,有效范围从 0 到 %d",DATASIZE);
         return false;
     }

     payload = payload - sizeof(LONGLONG); 

     struct hostent* phostent  = gethostbyname(target);
     if (!phostent)
     {
         printf("解析IP失败!\n");
         return false;
     }

     struct in_addr addrSrv = {};
     addrSrv.S_un.S_addr    = *(u_long *)phostent->h_addr_list[];

     printf("正在 Ping %s [%s] 具有 %d 字节的数据: \n",target,inet_ntoa(addrSrv),payload + sizeof(LONGLONG));

     icmphdr ihdr        = {};
     iphdr   ip_hdr      = {};
     ethhdr  eth_hdr     = {};

     unsigned char mac_src[] = "\x68\xf7\x28\x7f\xc2\x71"; //本机MAC地址
     unsigned char mac_dst[] = "\x84\xd9\x31\xb9\x21\x98"; //目的MAC地址

     memcpy((void *)eth_hdr.mac_src,(void *)mac_src,sizeof(mac_src) -);
     memcpy((void *)eth_hdr.mac_dst,(void *)mac_dst,sizeof(mac_dst) -);

     eth_hdr.eth_protocol  = htons(); //0x0800 //链路层IP数据报

     ip_hdr.ip_hdr_len      = 0xf; //包头设置为最大长度
     ip_hdr.ip_version      = ;
     ip_hdr.ip_identify     = (unsigned short)GetCurrentProcessId();
     ip_hdr.ip_offset       = ;
     ip_hdr.ip_ttl          = 0x40;//默认设置为64
     ip_hdr.ip_protocol     = IPPROTO_ICMP;
     ip_hdr.ip_src.s_addr   = inet_addr("172.30.1.145"); //本机IP
     ip_hdr.ip_dst.s_addr   = *(u_long *)phostent->h_addr_list[];
     ip_hdr.ip_code         = OPTION_RR;    //RR选项为7
     ip_hdr.ip_len          = 0x27;          //39字节 最多能存9个IP地址
     ip_hdr.ip_ptr          = ;
     ip_hdr.ip_cksum        = ;

     memset((void *)ip_hdr.ip_router,,sizeof(struct in_addr) * IPCOUNT);

     memset((void *)ihdr.icmp_data,,DATASIZE);
     memset((void *)ip_hdr.ip_data,,DATASIZE);

     packet_pad(ihdr.icmp_data,payload); //填充数据

     ihdr.icmp_type       = ECHO_REQUEST;
     ihdr.icmp_identify   = (unsigned short)GetCurrentProcessId();

     int hdr_len           = payload + sizeof(icmphdr) - DATASIZE;
     int datalen           = hdr_len + (ip_hdr.ip_hdr_len << );
     int sendlen           = datalen + sizeof(ethhdr) - DATASIZE;
     ip_hdr.ip_length      = htons(datalen);

     char recv[PACKETSIZE]   = {};

     unsigned long interval  = ;
     unsigned long avgdelay  = ;
     unsigned long maxdelay  = ;
     unsigned long mindelay  = ~;

     unsigned int  sendcnt   = count;
     unsigned int  losscnt   = ;

     char strErrorbuf[PCAP_ERRBUF_SIZE] = {};

     std::string strNickName = "\\Device\\NPF_{D8AECAAE-F28C-4161-BA6B-BCA1B807F2E5}"; //本机网卡

     pcap_t* pcap_handle  = NULL;
     if ((pcap_handle = pcap_open_live(strNickName.c_str(),,,,strErrorbuf))==NULL)
     {
         return false;
     }

     if( pcap_datalink(pcap_handle) != DLT_EN10MB )
     {
         return false;
     }

     unsigned int netip,netmask;
     if (pcap_lookupnet(strNickName.c_str(),&netip,&netmask,strErrorbuf) < )
     {
         return false;
     }

     std::string strFilter = "icmp"; //协议过滤  只抓icmp的包
     struct bpf_program nFcode;
     if ( pcap_compile(pcap_handle, &nFcode,strFilter.c_str(), , netmask) <  )
     {
         return false;
     }

     if ( pcap_setfilter(pcap_handle, &nFcode) <  )
     {
         return false;
     }

     int next = ;

     struct pcap_pkthdr *  header    = NULL;
     const unsigned char*  pkt_data  = NULL;

     for(int seq = ; seq < count; ++seq)
     {
         memset((void *)ip_hdr.ip_router,,sizeof(struct in_addr) * IPCOUNT);

         ihdr.icmp_seq        = seq;
         ihdr.icmp_cksum      = ;
         ihdr.icmp_timestamp  = GetSysTickCount64(); //发送时间
         ihdr.icmp_cksum      = checksum(hdr_len,(unsigned short *)&ihdr);

         memcpy((void *)ip_hdr.ip_data,(void *)&ihdr,hdr_len);

         ip_hdr.ip_cksum      = ;
         ip_hdr.ip_ptr        = ;
         ip_hdr.ip_cksum      = checksum(datalen,(unsigned short *)&ip_hdr);

         memcpy((void *)eth_hdr.eth_data,(void *)&ip_hdr,datalen);

         if(pcap_sendpacket(pcap_handle,(unsigned char *)&eth_hdr,sendlen) != ) //发送数据包
         {
             --sendcnt;
             continue;
         }

         while(next = pcap_next_ex(pcap_handle, &header, &pkt_data))
         {
             iphdr* piphdr = (iphdr *) (pkt_data + sizeof(ethhdr) - DATASIZE);

             if(checksum(piphdr->ip_hdr_len << ,(unsigned short *)piphdr) != )
             {
                 printf("invalid ip packet!\n");
                 continue;
             }

             icmphdr* pichdr = (icmphdr *)(pkt_data + sendlen - hdr_len);
             if(checksum(hdr_len,(unsigned short *)pichdr) != )
             {
                 printf("invalid icmp packet!\n");
                 continue;
             }

             if(piphdr->ip_ptr == )
             {
                 continue;
             }

             memcpy((void *)piphdr->ip_router,(void *)((char *)piphdr->ip_router -),sizeof(struct in_addr) * IPCOUNT);//内存对齐问题 

             interval = GetSysTickCount64() - pichdr->icmp_timestamp;
             avgdelay+= interval;

             maxdelay = interval > maxdelay ? interval : maxdelay;
             mindelay = interval > mindelay ? mindelay : interval;

             int record = (piphdr->ip_ptr-) >> ;

             printf("来自 %s 的回复: 字节=%d 时间=%dms TTL=%u\n",inet_ntoa(addrSrv),payload + sizeof(LONGLONG),interval,piphdr->ip_ttl);

             printf("    路由: %s -->\n",inet_ntoa(piphdr->ip_router[]));
             for(int i = ; i < record;i++)
             {
                 printf("           %s -->\n",inet_ntoa(piphdr->ip_router[i]));
             }

             break;
         }

         if(next == -)
         {
             losscnt++;
         }

     }

     printf("\n");
     printf("%s 的 Ping 统计信息: \n",inet_ntoa(addrSrv));
     printf("    数据包: 已发送 = %d, 已接收 = %d, 丢失 = %d (%.2f%% 丢失),\n",sendcnt,sendcnt-losscnt,losscnt,(losscnt * ) / (double)sendcnt);
     printf("往返行程的估计时间(以毫秒为单位):\n");
     printf("    最短 = %dms, 最长 = %dms, 平均 = %dms\n",mindelay,maxdelay,avgdelay / sendcnt);
     printf("\n");

     return true;
 }