抄写了一次ping程序

最新推荐文章于 2022-10-26 13:00:40 发布

转载最新推荐文章于 2022-10-26 13:00:40 发布 · 700 阅读

文章标签：

#socket #struct #tcp

本文介绍了一个使用C++实现的自定义Ping程序，该程序通过发送ICMP请求并接收响应来测试网络连通性。文章详细展示了如何构建IP和ICMP头部信息，计算校验和，并解析回应数据。

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// Ping_Project.cpp : Defines the entry point for the console application.
//
#include
#include "stdafx.h"
#include
#include
#pragma comment(lib,"WS2_32.lib")
char szDestIP[]="119.147.15.11";
int checksum(USHORT* buff, int size);
int recSize=0;
BOOL    HandPacket(char * Packet, SOCKADDR_IN sockFrom);
#define PROTO_ICMP    1
#define PROTO_IGMP    2
#define PROTO_TCP     6
#define PROTO_UDP     17
typedef struct _IPHeader        // 20字节的IP头
{
    UCHAR     iphVerLen;      // 版本号和头长度（各占4位）
    UCHAR     ipTOS;          // 服务类型
    USHORT    ipLength;       // 封包总长度，即整个IP报的长度
    USHORT    ipID;           // 封包标识，惟一标识发送的每一个数据报
    USHORT    ipFlags;        // 标志
    UCHAR     ipTTL;          // 生存时间，就是TTL
    UCHAR     ipProtocol;     // 协议，可能是TCP、UDP、ICMP等
    USHORT    ipChecksum;     // 校验和
    ULONG     ipSource;       // 源IP地址
    ULONG     ipDestination; // 目标IP地址
} IPHeader, *PIPHeader;
typedef struct ICMPHeader
{
    unsigned char   icmp_type;
    unsigned char   icmp_code;
    unsigned short icmp_checksum;
    //回显头
    unsigned short icmd_id;
    unsigned short icmp_sequence;
    unsigned long   icmp_timestamp;
} ICMPH;
int main(int argc, char* argv[])
{
    printf("%d,%d/r/n",sizeof(IPHeader),sizeof(ICMPH));
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2,1),&wsaData) != 0)
        ;
    SOCKET sRaw    =socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
    SOCKADDR_IN dest;
    char sendBuf[sizeof(ICMPHeader)+32];
    dest.sin_family =   AF_INET;
    dest.sin_port   =   htons(0);
    dest.sin_addr.S_un.S_addr   =   inet_addr(szDestIP);
    ICMPHeader *icmpHeader =(ICMPHeader*)sendBuf;
    ZeroMemory(icmpHeader, sizeof(ICMPHeader));
    icmpHeader->icmp_code    =   0;
    icmpHeader->icmp_type    =   8;
    icmpHeader->icmp_checksum    =   0;
    icmpHeader->icmd_id      =   (unsigned short)GetCurrentProcessId();
    int count=0;
    char recBuff[1024];
    SOCKADDR_IN from;
    int nLen = sizeof(from);
    int nRet=0;
    while(1)
    {
        count++;
        if (count==4)
        {
            break;
        }
        icmpHeader->icmp_code    =   0;
        icmpHeader->icmp_type    =   8;
        icmpHeader->icmd_id      =   (unsigned short)GetCurrentProcessId();
        icmpHeader->icmp_sequence    =count;
        icmpHeader->icmp_timestamp   =GetTickCount();
        icmpHeader->icmp_checksum    =0;//有必要设置为0再算
        icmpHeader->icmp_checksum    =checksum((USHORT*)sendBuf, sizeof(sendBuf));
        sendto(sRaw, sendBuf, sizeof(sendBuf), 0, (SOCKADDR*)&dest, sizeof(dest));
        if(nRet == SOCKET_ERROR)
        {
            printf(" sendto() failed: %d /n", ::WSAGetLastError());
        // return -1;
            continue;
        }
        ZeroMemory(recBuff, 1024);
        recSize=nRet    =recvfrom(sRaw, recBuff, 1024, 0, (SOCKADDR*)&from, &nLen);
        if (nRet    == SOCKET_ERROR)
        {
            if (WSAGetLastError()==WSAETIMEDOUT)
            {
                printf("request time out!/r/n");
                return 1;
            }
            printf(" recvfrom() failed: %d /n", ::WSAGetLastError());
        // return -1;
            continue;
        }
        if(nRet < sizeof(IPHeader) + sizeof(ICMPHeader))
        {
            printf(" Too few bytes from %s /n", ::inet_ntoa(from.sin_addr));
        }
        HandPacket((char*)recBuff, from);
    // Sleep(11);
    }
    WSACleanup();
    return 0;
}
///////////////////////////////////////////////////
int checksum(USHORT* buff, int size)
{
/*
    unsigned long cksum = 0;
    while(size>1)
    {
        cksum += *buff++;
        size -= sizeof(USHORT);
    }
    // 是奇数
    if(size)
    {
        cksum += *(UCHAR*)buff;
    }
    // 将32位的chsum高16位和低16位相加，然后取反
    cksum = (cksum >> 16) + (cksum & 0xffff);
    cksum += (cksum >> 16);
    return (USHORT)(~cksum);
*/
        int checksum=0;
        while(size>1)
        {
            checksum+=*(buff++);
            size-=2;
        }
        if (size)
        {
            checksum+=*(UCHAR*)buff;
        }
        checksum    = (checksum>>16)+(checksum&0xffff);
        checksum+=checksum>>16;
        return ~checksum;
}
BOOL    HandPacket(char * Packet, SOCKADDR_IN sockFrom)
{
    IPHeader* ipHder=(IPHeader*)Packet;
    ICMPHeader *icmphder=(ICMPHeader*)(Packet+sizeof(IPHeader));
    if (icmphder->icmd_id!=GetCurrentProcessId())
    {
        printf("someone else's packet");
        return TRUE;
    }
    if (icmphder->icmp_type!=0)
    {
        printf("not echo type icmpPacket");
        return TRUE;
    }
    int nTick=GetTickCount();
    printf("Reply %d bytes from %s:", strlen((char*)icmphder+sizeof(ICMPHeader)), inet_ntoa(sockFrom.sin_addr));
    printf(" icmp_seq=%d. TTL=%d", icmphder->icmp_sequence,ipHder->ipTTL);
    printf(" time: %dms Protocol:%d", nTick - icmphder->icmp_timestamp, ipHder->ipProtocol);
    printf(" /n");
// printf(" ip: %d /r/n", ipHder->ipSource);
    return TRUE;
}