【网络编程】之十三、ping程序实现

使用原始套接字：SOCK_RAW

需要ICMP

代码如下：

 #include
 #include

 using namespace std;

 #pragma comment(lib, "WS2_32.lib")

 typedef struct icmp_hdr{
     unsigned char icmp_type;
     unsigned char icmp_code;
     unsigned short icmp_checksum;
     unsigned short icmp_id;
     unsigned short icmp_sequence;
     unsigned long icmp_timnestamp;
 }ICMP_HDR, *PICMP_HDR;


 typedef struct _IPHeader{
     UCHAR iphVerLen;
     UCHAR ipTOS;
     USHORT ipLength;
     USHORT ipID;
     USHORT ipFlags;
     UCHAR ipTTL;
     UCHAR ipProtocol;
     USHORT ipChecksum;
     ULONG ipSource;
     ULONG ipDestination;
 }IPHeader, *PIPHeader;

 USHORT checksum(USHORT* buffer, int size)
 {
     unsigned long cksum = 0;

     while(size > 1)
     {
         cksum += *buffer++;
         size -= sizeof(USHORT);
     }

     // 奇数，将最后一个字节扩展到双字， 再累加
     if(size)
         cksum += *(UCHAR*)buffer;

     //高16  低16相加，取反
     cksum = (cksum >> 16) + (cksum & 0xffff);
     cksum += (cksum >> 16);
     return (USHORT)(~cksum);
 }

 int main(void)
 {
     char szDestIp[] = "127.0.0.1";
     SOCKET sRaw= ::socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
     //SetTimeout(sRaw, 1000, TRUE);

     SOCKADDR_IN dest;
     dest.sin_family = AF_INET;
     dest.sin_port = htons(5674);
     dest.sin_addr.S_un.S_addr = inet_addr(szDestIp);

     char buff[sizeof(ICMP_HDR) + 32];
     ICMP_HDR *pIcmp = (ICMP_HDR*)buff;
     pIcmp->icmp_type = 8;
     pIcmp->icmp_code = 0;
     pIcmp->icmp_id = (USHORT)::GetCurrentProcess();
     pIcmp->icmp_checksum = 0;
     pIcmp->icmp_sequence = 0;
     memset(&buff[sizeof(ICMP_HDR)], 'E', 32);

     //发送
     USHORT nSeq = 0;
     char recvBuf[1024];
     SOCKADDR_IN from;
     int nLen = sizeof(from);
     while(TRUE)
     {
         static int nCount = 0;
         int nRet;
         if(nCount++ == 4)
             break;
         pIcmp->icmp_checksum = 0;
         pIcmp->icmp_timnestamp = ::GetTickCount();
         pIcmp->icmp_sequence = nSeq++;
         pIcmp->icmp_checksum = checksum((USHORT*)buff, sizeof(ICMP_HDR) + 32);
         nRet = ::sendto(sRaw, buff, sizeof(ICMP_HDR) + 32, 0, (SOCKADDR*)&dest, sizeof(dest));
         if(nRet == SOCKET_ERROR)
         {
             cout << "sendto error:" << ::WSAGetLastError() << endl;
             return -1;
         }

         nRet = ::recvfrom(sRaw, recvBuf, 1024, 0, (sockaddr*)&from, &nLen);
         if(nRet == SOCKET_ERROR)
         {
             if(::WSAGetLastError() == WSAETIMEDOUT)
             {
                 cout << "time out" << endl;
                 continue;
             }
             cout << "recvfrom failed:" << ::WSAGetLastError() << endl;
             return -1;
         }

         //解析
         int nTick = ::GetTickCount();
         if(nRet < sizeof(IPHeader) + sizeof(ICMP_HDR))
         {
             cout << "Too few bytes from " << ::inet_ntoa(from.sin_addr) << endl;
         }

         ICMP_HDR *pRecvIcmp = (ICMP_HDR*)(recvBuf + sizeof(IPHeader));
         if(pRecvIcmp->icmp_type != 0)
         {
             cout << "nonecho type " << pRecvIcmp->icmp_type << " recvd" << endl;
             return -1;
         }
         if(pRecvIcmp->icmp_id != ::GetCurrentProcessId())
         {
             cout << "someone ele's packet!" << endl;
             return -1;
         }

         cout << nRet << " bytes from " << inet_ntoa(from.sin_addr) ;
         cout << "icmp_seq = " << pRecvIcmp->icmp_sequence ;
         cout << "time: " << nTick - pRecvIcmp->icmp_timnestamp << " ms";
         cout << endl;
         Sleep(1000);
     }


     return 0;
 }

                                                                                                         jofranks  13.7.24 于南昌

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