//IP数据报头
typedef struct
{
    unsigned char hdr_len : 4;  // 4位首部长度
    unsigned char version : 4;  // 4位版本号
    unsigned char tos;   // 8位服务类型
    unsigned short total_len;  // 16位总长度
    unsigned short identifier;  // 16位标识位
    unsigned short frag_and_flags; // flags
    unsigned char ttl;   // 8位生存时间（TTL）
    unsigned char protocol;  // 8位上层协议
    unsigned short checksum;  // 16位校验和
    unsigned long sourceIP;  // 源IP地址
    unsigned long destIP;   // 目标IP地址
} IP_HEADER;

//ICMP数据报头
typedef struct
{
    BYTE type;  //8位类型
    BYTE code;  //8位代码
    USHORT cksum;  //16位校验和
    USHORT id;   //16位标识符
    USHORT seq;  //16位序列号
} ICMP_HEADER;

Code:

TraceRoute.h

#pragma once

#include <windows.h>

#pragma pack(1)
//IP数据报头
typedef struct
{
    unsigned char hdr_len : 4;  // 4位首部长度
    unsigned char version : 4;  // 4位版本号
    unsigned char tos;   // 8位服务类型
    unsigned short total_len;  // 16位总长度
    unsigned short identifier;  // 16位标识位
    unsigned short frag_and_flags; // flags
    unsigned char ttl;   // 8位生存时间（TTL）
    unsigned char protocol;  // 8位上层协议
    unsigned short checksum;  // 16位校验和
    unsigned long sourceIP;  // 源IP地址
    unsigned long destIP;   // 目标IP地址
} IP_HEADER;

//ICMP数据报头
typedef struct
{
    BYTE type;  //8位类型
    BYTE code;  //8位代码
    USHORT cksum;  //16位校验和
    USHORT id;   //16位标识符
    USHORT seq;  //16位序列号
} ICMP_HEADER;

//解码结果
typedef struct
{
    USHORT usSeqNo;   //包序列号
    DWORD dwRoundTripTime; //往返时间
    in_addr dwIPaddr;  //对端IP地址
} DECODE_RESULT;
#pragma pack()

const BYTE ICMP_ECHO_REQUEST = 8; //请求回显
const BYTE ICMP_ECHO_REPLY = 0; //回显应答
const BYTE ICMP_TIMEOUT = 11; //传输超时

const int DEF_MAX_HOP = 30;    //最大跳站数
const DWORD DEF_ICMP_TIMEOUT = 3000; //默认超时时间，单位ms
const int DEF_ICMP_DATA_SIZE = 32; //默认ICMP数据部分长度
const int MAX_ICMP_PACKET_SIZE = 1024; //最大ICMP数据报的大小

USHORT GenerateChecksum(USHORT* pBuf, int iSize);
BOOL DecodeIcmpResponse(char* pBuf, int iPacketSize, DECODE_RESULT& stDecodeResult);

TraceRoute.cpp

#define _WINSOCK_DEPRECATED_NO_WARNINGS 

#include <iostream>
#include <ws2tcpip.h>
#include <winsock2.h>
#include <iomanip>
#include "TraceRoute.h"

#pragma comment(lib,"ws2_32")

using namespace std;

int main(int argc, char* argv[]) {

    //检查命令行参数
    if (argc != 2)
    {
        cerr << "\nUsage: itracert ip_or_hostname\n";
        return -1;
    }
    //初始化winsock2环境
    WSADATA wsa;
    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
    {
        cerr << "\nFailed to initialize the WinSock2 DLL\n"
            << "error code: " << WSAGetLastError() << endl;
        return -1;
    }

    //将命令行参数转换为IP地址
    u_long ulDestIP = inet_addr(argv[1]);
    if (ulDestIP == INADDR_NONE){

        //转换不成功时按域名解析
        hostent* pHostent = gethostbyname(argv[1]);
        if (pHostent)
        {
            ulDestIP = (*(in_addr*)pHostent->h_addr).s_addr;
            //输出屏幕信息
            cout << "\nTracing route to " << argv[1]
                << " [" << inet_ntoa(*(in_addr*)(&ulDestIP)) << "]"
                << " with a maximum of " << DEF_MAX_HOP << " hops.\n" << endl;
        }
        else //解析主机名失败
        {
            cerr << "\nCould not resolve the host name " << argv[1] << '\n'
                << "error code: " << WSAGetLastError() << endl;
            WSACleanup();
            return -1;
        }
    }
    else{

        //输出屏幕信息
        cout << "\nTracing route to " << argv[1]
            << " with a maximum of " << DEF_MAX_HOP << " hops.\n" << endl;
    }

    //填充目的Socket地址
    sockaddr_in destSockAddr;
    ZeroMemory(&destSockAddr, sizeof(sockaddr_in));
    destSockAddr.sin_family = AF_INET;
    destSockAddr.sin_addr.s_addr = ulDestIP;
    //使用ICMP协议创建Raw Socket
    SOCKET sockRaw = WSASocket(AF_INET, SOCK_RAW, IPPROTO_ICMP, NULL, 0, WSA_FLAG_OVERLAPPED);
    if (sockRaw == INVALID_SOCKET)
    {
        cerr << "\nFailed to create a raw socket\n"
            << "error code: " << WSAGetLastError() << endl;
        WSACleanup();
        return -1;
    }

    //设置端口属性
    int iTimeout = DEF_ICMP_TIMEOUT;
    if (setsockopt(sockRaw, SOL_SOCKET, SO_RCVTIMEO, (char*)&iTimeout, sizeof(iTimeout)) == SOCKET_ERROR)
    {
        cerr << "\nFailed to set recv timeout\n"
            << "error code: " << WSAGetLastError() << endl;
        closesocket(sockRaw);
        WSACleanup();
        return -1;
    }
    //创建ICMP包发送缓冲区和接收缓冲区
    char IcmpSendBuf[sizeof(ICMP_HEADER) + DEF_ICMP_DATA_SIZE];
    memset(IcmpSendBuf, 0, sizeof(IcmpSendBuf));
    char IcmpRecvBuf[MAX_ICMP_PACKET_SIZE];
    memset(IcmpRecvBuf, 0, sizeof(IcmpRecvBuf));

    //填充待发送的ICMP包
    ICMP_HEADER* pIcmpHeader = (ICMP_HEADER*)IcmpSendBuf;
    pIcmpHeader->type = ICMP_ECHO_REQUEST;
    pIcmpHeader->code = 0;
    pIcmpHeader->id = (USHORT)GetCurrentProcessId();
    memset(IcmpSendBuf + sizeof(ICMP_HEADER), 'E', DEF_ICMP_DATA_SIZE);

    //开始探测路由
    DECODE_RESULT stDecodeResult;
    BOOL bReachDestHost = FALSE;
    USHORT usSeqNo = 0;
    int iTTL = 1;
    int iMaxHop = DEF_MAX_HOP;

    while (!bReachDestHost && iMaxHop--) {
    
        //设置IP数据报头的ttl字段
        setsockopt(sockRaw, IPPROTO_IP, IP_TTL, (char*)&iTTL, sizeof(iTTL));
        //输出当前跳站数作为路由信息序号
        cout << setw(3) << iTTL << flush;

        //填充ICMP数据报剩余字段
        ((ICMP_HEADER*)IcmpSendBuf)->seq = htons(usSeqNo++);
        ((ICMP_HEADER*)IcmpSendBuf)->cksum = GenerateChecksum((USHORT*)IcmpSendBuf, sizeof(ICMP_HEADER) + DEF_ICMP_DATA_SIZE);

        //记录序列号和当前时间
        stDecodeResult.usSeqNo = ((ICMP_HEADER*)IcmpSendBuf)->seq;
        stDecodeResult.dwRoundTripTime = GetTickCount();

        //发送ICMP的EchoRequest数据报
        if (sendto(sockRaw, IcmpSendBuf, sizeof(IcmpSendBuf), 0,
            (sockaddr*)&destSockAddr, sizeof(destSockAddr)) == SOCKET_ERROR){

            //如果目的主机不可达则直接退出
            if (WSAGetLastError() == WSAEHOSTUNREACH)
                cout << '\t' << "Destination host unreachable./n"
                << "\nTrace complete.\n" << endl;
            closesocket(sockRaw);
            WSACleanup();
            return 0;
        }

        //接收ICMP的EchoReply数据报
        //因为收到的可能并非程序所期待的数据报，所以需要循环接收直到收到所要数据或超时
        sockaddr_in from;
        int iFromLen = sizeof(from);
        int iReadDataLen;
        while (1){

            //等待数据到达
            iReadDataLen = recvfrom(sockRaw, IcmpRecvBuf, MAX_ICMP_PACKET_SIZE,
                0, (sockaddr*)&from, &iFromLen);
            if (iReadDataLen != SOCKET_ERROR) //有数据包到达
            {
                //解码得到的数据包，如果解码正确则跳出接收循环发送下一个EchoRequest包
                if (DecodeIcmpResponse(IcmpRecvBuf, iReadDataLen, stDecodeResult))
                {
                    if (stDecodeResult.dwIPaddr.s_addr == destSockAddr.sin_addr.s_addr)
                        bReachDestHost = TRUE;
                    cout << '\t' << inet_ntoa(stDecodeResult.dwIPaddr) << endl;
                    break;
                }
            }
            else if (WSAGetLastError() == WSAETIMEDOUT) //接收超时，打印星号
            {
                cout << setw(9) << '*' << '\t' << "Request timed out." << endl;
                break;
            }
            else
            {
                cerr << "\nFailed to call recvfrom\n"
                    << "error code: " << WSAGetLastError() << endl;
                closesocket(sockRaw);
                WSACleanup();
                return -1;
            }
        }
        //TTL值加1
        iTTL++;
    }
    //输出屏幕信息
    cout << "\nTrace complete.\n" << endl;
    closesocket(sockRaw);
    WSACleanup();
    return 0;
}

//产生网际校验和
USHORT GenerateChecksum(USHORT* pBuf, int iSize)
{
    unsigned long cksum = 0;
    while (iSize>1)
    {
        cksum += *pBuf++;
        iSize -= sizeof(USHORT);
    }
    if (iSize)
        cksum += *(UCHAR*)pBuf;
    cksum = (cksum >> 16) + (cksum & 0xffff);
    cksum += (cksum >> 16);
    return (USHORT)(~cksum);
}


//解码得到的数据报
BOOL DecodeIcmpResponse(char* pBuf, int iPacketSize, DECODE_RESULT& stDecodeResult)
{
    //检查数据报大小的合法性
    IP_HEADER* pIpHdr = (IP_HEADER*)pBuf;
    int iIpHdrLen = pIpHdr->hdr_len * 4;
    if (iPacketSize < (int)(iIpHdrLen + sizeof(ICMP_HEADER)))
        return FALSE;
    //按照ICMP包类型检查id字段和序列号以确定是否是程序应接收的Icmp包
    ICMP_HEADER* pIcmpHdr = (ICMP_HEADER*)(pBuf + iIpHdrLen);
    USHORT usID, usSquNo;
    if (pIcmpHdr->type == ICMP_ECHO_REPLY){

        usID = pIcmpHdr->id;
        usSquNo = pIcmpHdr->seq;
    }else if (pIcmpHdr->type == ICMP_TIMEOUT){

        char* pInnerIpHdr = pBuf + iIpHdrLen + sizeof(ICMP_HEADER);  //载荷中的IP头
        int iInnerIPHdrLen = ((IP_HEADER*)pInnerIpHdr)->hdr_len * 4;//载荷中的IP头长
        ICMP_HEADER* pInnerIcmpHdr = (ICMP_HEADER*)(pInnerIpHdr + iInnerIPHdrLen);//载荷中的ICMP头
        usID = pInnerIcmpHdr->id;
        usSquNo = pInnerIcmpHdr->seq;
    }else
        return FALSE;

    if (usID != (USHORT)GetCurrentProcessId() || usSquNo != stDecodeResult.usSeqNo)
        return FALSE;
    //处理正确收到的ICMP数据报
    if (pIcmpHdr->type == ICMP_ECHO_REPLY || pIcmpHdr->type == ICMP_TIMEOUT){

        //返回解码结果
        stDecodeResult.dwIPaddr.s_addr = pIpHdr->sourceIP;
        stDecodeResult.dwRoundTripTime = GetTickCount() - stDecodeResult.dwRoundTripTime;
        //打印屏幕信息
        if (stDecodeResult.dwRoundTripTime)
            cout << setw(6) << stDecodeResult.dwRoundTripTime << " ms" << flush;
        else
            cout << setw(6) << "<1" << " ms" << flush;
        return TRUE;
    }
    return FALSE;
}