一种比较简单的实现ping的方式

<span style="font-family: Arial, Helvetica, sans-serif;">头文件</span>

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<span style="font-family: Arial, Helvetica, sans-serif;">#ifndef __PING_H__</span>

#define __PING_H__
//
// Ping.h
//
#pragma once
#pragma pack(1)

#include <winsock2.h>

#define ICMP_ECHOREPLY	0
#define ICMP_ECHOREQ	8

#define PINGERR_SOCKET_ERROR -1
#define PINGERR_TIMEOUT      -2
#define PINGERR_NOHOST       -3
class CPing
{
public:
	int Ping(int ip);

protected:
	int  WaitForEchoReply(SOCKET s);
	// ICMP Echo Request/Reply functions
	int		SendEchoRequest(SOCKET, LPSOCKADDR_IN);
	DWORD	RecvEchoReply(SOCKET, LPSOCKADDR_IN, u_char *);
	u_short in_cksum(u_short *addr, int len);
};

// IP Header -- RFC 791
typedef struct tagIPHDR
{
	u_char  VIHL;			// Version and IHL
	u_char	TOS;			// Type Of Service
	short	TotLen;			// Total Length
	short	ID;				// Identification
	short	FlagOff;		// Flags and Fragment Offset
	u_char	TTL;			// Time To Live
	u_char	Protocol;		// Protocol
	u_short	Checksum;		// Checksum
	struct	in_addr iaSrc;	// Internet Address - Source
	struct	in_addr iaDst;	// Internet Address - Destination
}IPHDR, *PIPHDR;

// ICMP Header - RFC 792
typedef struct tagICMPHDR
{
	u_char	Type;			// Type
	u_char	Code;			// Code
	u_short	Checksum;		// Checksum
	u_short	ID;				// Identification
	u_short	Seq;			// Sequence
	char	Data;			// Data
}ICMPHDR, *PICMPHDR;

#define REQ_DATASIZE 32		// Echo Request Data size

// ICMP Echo Request
typedef struct tagECHOREQUEST
{
	ICMPHDR icmpHdr;
	DWORD	dwTime;
	char	cData[REQ_DATASIZE];
}ECHOREQUEST, *PECHOREQUEST;

// ICMP Echo Reply
typedef struct tagECHOREPLY
{
	IPHDR	ipHdr;
	ECHOREQUEST	echoRequest;
	char    cFiller[256];
}ECHOREPLY, *PECHOREPLY;

#pragma pack()

#endif

实现

//
// THIS CODE IS BASED ON THE CODE FROM
// THE BOOK WINSOCK 2.0 BY LEWIS NAPPER...
//
//

#include "ping.h"
#include <Mmsystem.h>
#pragma comment( lib,"winmm.lib" )
#pragma comment(lib,"ws2_32.lib")

int CPing::Ping(int ip)
{
	SOCKET	  rawSocket;
	int       nRet;
	struct    sockaddr_in saDest;
	struct    sockaddr_in saSrc;
	DWORD	  dwTimeSent;
	DWORD	  dwElapsed;
	u_char    cTTL;

	// Create a Raw socket
	rawSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
	if (rawSocket == SOCKET_ERROR)
	{
		return PINGERR_SOCKET_ERROR;
	}

	// Setup destination socket address
	saDest.sin_addr.s_addr = ip;
	saDest.sin_family = AF_INET;
	saDest.sin_port   = 0;

    // Send ICMP echo request
    SendEchoRequest(rawSocket, &saDest);

    nRet = WaitForEchoReply(rawSocket);
    if (nRet == SOCKET_ERROR)
    {
        return PINGERR_SOCKET_ERROR;
    }

    if (!nRet)
    {
        return PINGERR_TIMEOUT;
    }
    else
    {
        // Receive reply
        dwTimeSent = RecvEchoReply(rawSocket, &saSrc, &cTTL);
        // Calculate elapsed time
        dwElapsed = timeGetTime() - dwTimeSent;

    }
    nRet = closesocket(rawSocket);

    return (int)dwElapsed;
}

int CPing::SendEchoRequest(SOCKET s,LPSOCKADDR_IN lpstToAddr)
{
	static ECHOREQUEST echoReq;
	static int nId = 1;
	static int nSeq = 1;
	int nRet;

	// Fill in echo request
	echoReq.icmpHdr.Type		= ICMP_ECHOREQ;
	echoReq.icmpHdr.Code		= 0;
	echoReq.icmpHdr.Checksum	= 0;
	echoReq.icmpHdr.ID			= u_short(nId++);
	echoReq.icmpHdr.Seq			= u_short(nSeq++);

	// Fill in some data to send
	for (nRet = 0; nRet < REQ_DATASIZE; nRet++)
		echoReq.cData[nRet] = char(' '+nRet);

	// Save tick count when sent
	echoReq.dwTime				= timeGetTime();

	// Put data in packet and compute checksum
	echoReq.icmpHdr.Checksum = in_cksum((u_short *)&echoReq, sizeof(ECHOREQUEST));

	// Send the echo request
	nRet = sendto(s,						/* socket */
				 (LPSTR)&echoReq,			/* buffer */
				 sizeof(ECHOREQUEST),
				 0,							/* flags */
				 (LPSOCKADDR)lpstToAddr, /* destination */
				 sizeof(SOCKADDR_IN));   /* address length */

	return (nRet);
}

DWORD CPing::RecvEchoReply(SOCKET s, LPSOCKADDR_IN lpsaFrom, u_char *pTTL)
{
	ECHOREPLY echoReply;
	int nRet;
	int nAddrLen = sizeof(struct sockaddr_in);

	// Receive the echo reply
	nRet = recvfrom(s,					// socket
					(LPSTR)&echoReply,	// buffer
					sizeof(ECHOREPLY),	// size of buffer
					0,					// flags
					(LPSOCKADDR)lpsaFrom,	// From address
					&nAddrLen);			// pointer to address len

	// return time sent and IP TTL
	*pTTL = echoReply.ipHdr.TTL;

	return(echoReply.echoRequest.dwTime);
}

int CPing::WaitForEchoReply(SOCKET s)
{
	struct timeval Timeout;
	fd_set readfds;

	readfds.fd_count = 1;
	readfds.fd_array[0] = s;
	Timeout.tv_sec = 1;
    Timeout.tv_usec = 0;

	return(select(1, &readfds, NULL, NULL, &Timeout));
}

//
// Mike Muuss' in_cksum() function
// and his comments from the original
// ping program
//
// * Author -
// *	Mike Muuss
// *	U. S. Army Ballistic Research Laboratory
// *	December, 1983

/*
 *			I N _ C K S U M
 *
 * Checksum routine for Internet Protocol family headers (C Version)
 *
 */
u_short CPing::in_cksum(u_short *addr, int len)
{
	register int nleft = len;
	register u_short *w = addr;
	register u_short answer;
	register int sum = 0;

	/*
	 *  Our algorithm is simple, using a 32 bit accumulator (sum),
	 *  we add sequential 16 bit words to it, and at the end, fold
	 *  back all the carry bits from the top 16 bits into the lower
	 *  16 bits.
	 */
	while( nleft > 1 )  {
		sum += *w++;
		nleft -= 2;
	}

	/* mop up an odd byte, if necessary */
	if( nleft == 1 ) {
		u_short	u = 0;

		*(u_char *)(&u) = *(u_char *)w ;
		sum += u;
	}

	/*
	 * add back carry outs from top 16 bits to low 16 bits
	 */
	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
	sum += (sum >> 16);			/* add carry */
	answer = u_short(~sum);				/* truncate to 16 bits */
	return (answer);
}