Ping程序示例

#include
#include
#include

struct ICMPheader
{
    unsigned char    byType;
    unsigned char    byCode;
    unsigned short    nChecksum;
    unsigned short    nId;
    unsigned short    nSequence;
};

struct IPheader
{
    unsigned char    byVerLen;       
    unsigned char    byTos;      
    unsigned short    nTotalLength;  
    unsigned short    nId;           
    unsigned short    nOffset;       
    unsigned char    byTtl;         
    unsigned char    byProtocol;    
    unsigned short    nChecksum;     
    unsigned int    nSrcAddr;      
    unsigned int    nDestAddr;     
};

using namespace std;

unsigned short CalcChecksum (char *pBuffer, int nLen);
bool ValidateChecksum (char *pBuffer, int nLen);
bool Initialize ();
bool UnInitialize ();
bool ResolveIP (char *pszRemoteHost, char **pszIPAddress);
void PrintUsage ();

int main(int argc, char* argv[])
{
    if (argc < 2 || argc > 5)
    {
        PrintUsage ();
        return 0;
    }

    if (Initialize () == false)
    {
        return -1;
    }

    int nSequence = 0;
    int nMessageSize = 32;    // ICMP包大小
    int nTimeOut = 5000;    // 请求超时值 (毫秒)
    int nCount = 4;            // 请求发送次数

    char *pszRemoteIP = NULL, *pSendBuffer = NULL, *pszRemoteHost = NULL;

    pszRemoteHost = argv [1];
   
    for (int i = 2; i < argc; ++i)
    {
        switch (i)
        {
        case 2:           
            nCount = atoi (argv [2]);
            break;
        case 3:
            nMessageSize = atoi (argv [3]);
            break;
        case 4:
            nTimeOut = atoi (argv [4]);
            break;
        }
    }

    if (ResolveIP (pszRemoteHost, &pszRemoteIP) == false)
    {
        cout << "Ping request could not find host " << pszRemoteHost << ".";
        cout << "Please check the name and try again." <<  endl;
        return -1;
    }

    cout << "Pinging " << pszRemoteHost << " [" << pszRemoteIP << "] with " << nMessageSize << " bytes of data." << endl << endl;
    ICMPheader sendHdr;

    SOCKET sock;
    sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);    // 创建原始套接字

    SOCKADDR_IN dest;             // 目标地址
    dest.sin_addr.S_un.S_addr = inet_addr (pszRemoteIP);
    dest.sin_family = AF_INET;
    dest.sin_port = rand ();    // 随机端口

    int nResult = 0;

    fd_set fdRead;
    SYSTEMTIME timeSend, timeRecv;
    int nTotalRoundTripTime = 0, nMaxRoundTripTime = 0, nMinRoundTripTime = -1, nRoundTripTime = 0;
    int nPacketsSent = 0, nPacketsReceived = 0;

    timeval timeInterval = {0, 0};
    timeInterval.tv_usec = nTimeOut * 1000;
   
    sendHdr.nId = htons (rand());    // 设置事务ID

    while (nPacketsSent < nCount)
    {
        // 创建消息缓冲区
        pSendBuffer = new char[sizeof (ICMPheader) + nMessageSize];

        sendHdr.byCode = 0;        // ICMP反射和应答
        sendHdr.nSequence = htons (nSequence++);
        sendHdr.byType = 8;        // ICMP反射
        sendHdr.nChecksum = 0;    // Checksum

        memcpy_s(pSendBuffer, sizeof (ICMPheader), &sendHdr, sizeof (ICMPheader));    // 拷贝消息头
        memset(pSendBuffer + sizeof (ICMPheader), 'x', nMessageSize);   

        // 计算checksum包括ICMP头和消息
        sendHdr.nChecksum = htons(CalcChecksum (pSendBuffer, sizeof (ICMPheader) + nMessageSize));   

        memcpy_s(pSendBuffer, sizeof (ICMPheader), &sendHdr, sizeof (ICMPheader));

        nResult = sendto(sock, pSendBuffer, sizeof (ICMPheader) + nMessageSize, 0, (SOCKADDR *)&dest, sizeof (SOCKADDR_IN));
       
        // 保存发送时间
        ::GetSystemTime(&timeSend);

        ++nPacketsSent;

        if (nResult == SOCKET_ERROR)
        {
            cerr << endl << "An error occured in sendto operation: " << "WSAGetLastError () = " << WSAGetLastError () << endl;
            UnInitialize ();
            delete []pSendBuffer;
            return -1;
        }
       
        FD_ZERO(&fdRead);
        FD_SET(sock, &fdRead);

        if ((nResult = select (0, &fdRead, NULL, NULL, &timeInterval))
            == SOCKET_ERROR)
        {
            cerr << endl << "An error occured in select operation: " << "WSAGetLastError () = " <<
                WSAGetLastError () << endl;
            delete []pSendBuffer;
            return -1;
        }

        if (nResult > 0 && FD_ISSET(sock, &fdRead))
        {
            // 分配空间给接收缓冲区
            char *pRecvBuffer = new char[1500];

            if ((nResult = recvfrom (sock, pRecvBuffer, 1500, 0, 0, 0))
                == SOCKET_ERROR)
            {
                cerr << endl << "An error occured in recvfrom operation: " << "WSAGetLastError () = " <<
                    WSAGetLastError () << endl;
                UnInitialize ();
                delete []pSendBuffer;
                delete []pRecvBuffer;
                return -1;
            }
           
            // 得到接收时间
            ::GetSystemTime(&timeRecv);

            ICMPheader recvHdr;
            char *pICMPbuffer = NULL;
 
            // 接收包含IP头
            pICMPbuffer = pRecvBuffer + sizeof(IPheader);

            int nICMPMsgLen = nResult - sizeof(IPheader);

            // 得到ICMP头
            memcpy_s(&recvHdr, sizeof(recvHdr), pICMPbuffer, sizeof(recvHdr));

            // 得到IP头
            IPheader ipHdr;
            memcpy_s(&ipHdr, sizeof(ipHdr), pRecvBuffer, sizeof(ipHdr));

            recvHdr.nId = recvHdr.nId;
            recvHdr.nSequence = recvHdr.nSequence;
            recvHdr.nChecksum = ntohs (recvHdr.nChecksum);

            // 检查事务ID和checksum
            if (recvHdr.byType == 0 &&
                recvHdr.nId == sendHdr.nId &&
                recvHdr.nSequence == sendHdr.nSequence &&
                ValidateChecksum (pICMPbuffer, nICMPMsgLen)  &&
                memcmp (pSendBuffer + sizeof(ICMPheader), pRecvBuffer + sizeof (ICMPheader) + sizeof(IPheader),
                    nResult - sizeof (ICMPheader) - sizeof(IPheader)) == 0)
            {
                int nSec = timeRecv.wSecond - timeSend.wSecond;
                if (nSec < 0)
                {
                    nSec = nSec + 60;
                }

                int nMilliSec = abs (timeRecv.wMilliseconds - timeSend.wMilliseconds);

                int nRoundTripTime = 0;
                nRoundTripTime = abs (nSec * 1000 - nMilliSec);

                cout << "Reply from " << pszRemoteIP << ": bytes = " << nResult - sizeof (ICMPheader) - sizeof (IPheader)
                    << ", time = " << nRoundTripTime << "ms, TTL = " << (int)ipHdr.byTtl << endl;

                nTotalRoundTripTime = nTotalRoundTripTime + nRoundTripTime;

                if (nMinRoundTripTime == -1)
                {
                    nMinRoundTripTime = nRoundTripTime;
                    nMaxRoundTripTime = nRoundTripTime;
                }
                else if (nRoundTripTime < nMinRoundTripTime)
                {
                    nMinRoundTripTime = nRoundTripTime;
                }
                else if (nRoundTripTime > nMaxRoundTripTime)
                {
                    nMaxRoundTripTime = nRoundTripTime;
                }

                ++nPacketsReceived;
            }
            else
            {
                cout << "The echo reply is not correct!" << endl;
            }

            delete [] pRecvBuffer;
        }
        else
        {
            cout << "Request timed out." << endl;
        }

        delete []pSendBuffer;
    }

    cout << endl << "Ping statistics for " << pszRemoteIP << ":" << endl << '\t' << "Packets: Sent = " << nPacketsSent << ", Received = " <<
        nPacketsReceived << ", Lost = " << (nPacketsSent - nPacketsReceived) << " (" <<
        ((nPacketsSent - nPacketsReceived)/(float)nPacketsSent) * 100 << "% loss)" << endl << '\t';

    if (nPacketsReceived > 0)
    {
        cout << "\rApproximate round trip times in milli-seconds:" << endl << '\t' << "Minimum = " << nMinRoundTripTime <<
            "ms, Maximum = " << nMaxRoundTripTime << "ms, Average = " << nTotalRoundTripTime / (float)nPacketsReceived << "ms" << endl;
    }

    cout << '\r' << endl;

    if (UnInitialize() == false)
    {
        return -1;
    }

    return 0;
}

unsigned short CalcChecksum (char *pBuffer, int nLen)
{
    unsigned short nWord;
    unsigned int nSum = 0;
    int i;
   
    for (i = 0; i < nLen; i = i + 2)
    {
        nWord =((pBuffer [i] << 8)& 0xFF00) + (pBuffer [i + 1] & 0xFF);
        nSum = nSum + (unsigned int)nWord;   
    }
   
    while (nSum >> 16)
    {
        nSum = (nSum & 0xFFFF) + (nSum >> 16);
    }

    nSum = ~nSum;
   
    return ((unsigned short) nSum);
}

bool ValidateChecksum (char *pBuffer, int nLen)
{
    unsigned short nWord;
    unsigned int nSum = 0;
    int i;
   
    for (i = 0; i < nLen; i = i + 2)
    {
        nWord =((pBuffer [i] << 8)& 0xFF00) + (pBuffer [i + 1] & 0xFF);
        nSum = nSum + (unsigned int)nWord;   
    }
   
    while (nSum >> 16)
    {
        nSum = (nSum & 0xFFFF) + (nSum >> 16);
    }

    return ((unsigned short)nSum == 0xFFFF);
}

bool Initialize ()
{
    WSADATA wsaData;

    if (WSAStartup (MAKEWORD (2, 2), &wsaData) == SOCKET_ERROR)
    {
        cerr << endl << "An error occured in WSAStartup operation: " << "WSAGetLastError () = " << WSAGetLastError () << endl;
        return false;
    }

    SYSTEMTIME time;
    ::GetSystemTime(&time);

    srand(time.wMilliseconds);

    return true;
}

bool UnInitialize ()
{
    if (WSACleanup () == SOCKET_ERROR)
    {
        cerr << endl << "An error occured in WSACleanup operation: WSAGetLastError () = " << WSAGetLastError () << endl;
        return false;
    }

    return true;
}

bool ResolveIP (char *pszRemoteHost, char **pszIPAddress)
{
    hostent *pHostent = gethostbyname (pszRemoteHost);
    if (pHostent == NULL)
    {
        cerr << endl << "An error occured in gethostbyname operation: WSAGetLastError () = " << WSAGetLastError () << endl;
        return false;
    }

    in_addr in;
    memcpy_s(∈, sizeof (in_addr), pHostent->h_addr_list [0], sizeof (in_addr));
    *pszIPAddress = inet_ntoa(in);

    return true;
}

void PrintUsage ()
{
    cout << "Usage: ping r n b t" << endl << endl;
    cout << "  r - Remote host" << endl;
    cout << "  n - Number of echo requests to send" << endl;
    cout << "  b - Bytes to send" << endl;
    cout << "  t - Timeout after these many milliseconds" << endl << endl;

    cout << "\rping microsoft.com 4 32 4000" << endl << endl;
}