Ping for Windows

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

#include "stdafx.h"
#include "ping.h"


void CPing::Ping(UINT nRetries,LPCSTR pstrHost,HWND hWnd)
{
	SOCKET	  rawSocket;
	LPHOSTENT lpHost;
	UINT	  nLoop;
	int       nRet;
	struct    sockaddr_in saDest;
	struct    sockaddr_in saSrc;
	DWORD	  dwTimeSent;
	DWORD	  dwElapsed;
	u_char    cTTL;


	m_hWnd = hWnd;

	CString str;

	ASSERT(IsWindow(hWnd));
	// Create a Raw socket
	rawSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
	if (rawSocket == SOCKET_ERROR) 
	{
		WSAError("socket()");
		return;
	}
	
	// Lookup host
	lpHost = gethostbyname(pstrHost);
	if (lpHost == NULL)
	{
		str.Format("Host not found: %s", pstrHost);
		::PostMessage(m_hWnd,WM_MSG_STATUS, 0, (LPARAM) AllocBuffer(str));
		::PostMessage(m_hWnd,WM_PING_END, 0, 0);
		return;
	}
	
	// Setup destination socket address
	saDest.sin_addr.s_addr = *((u_long FAR *) (lpHost->h_addr));
	saDest.sin_family = AF_INET;
	saDest.sin_port = 0;

	// Tell the user what we're doing
	str.Format("Pinging %s [%s] with %d bytes of data:",
				pstrHost,
				inet_ntoa(saDest.sin_addr),
				REQ_DATASIZE);
	::PostMessage(m_hWnd,WM_MSG_STATUS, 1, (LPARAM) AllocBuffer(str));

	// Ping multiple times
	for (nLoop = 0; nLoop < nRetries; nLoop++)
	{
		// Send ICMP echo request
		SendEchoRequest(rawSocket, &saDest);

		nRet = WaitForEchoReply(rawSocket);
		if (nRet == SOCKET_ERROR)
		{
			WSAError("select()");
			break;
		}
		if (!nRet)
		{
			str.Format("Request Timed Out");
			::PostMessage(m_hWnd,WM_MSG_STATUS, 3, (LPARAM) AllocBuffer(str));
		}
		else

		{

			// Receive reply
			dwTimeSent = RecvEchoReply(rawSocket, &saSrc, &cTTL);

			// Calculate elapsed time
			dwElapsed = GetTickCount() - dwTimeSent;
			str.Format("Reply[%d] from: %s: bytes=%d time=%ldms TTL=%d", 
				nLoop+1,
				   inet_ntoa(saSrc.sin_addr), 
				   REQ_DATASIZE,
				   dwElapsed,
				   cTTL);

			::PostMessage(m_hWnd,WM_MSG_STATUS, 2, (LPARAM) AllocBuffer(str));

			Sleep(1000);
		}
	}
	
	::PostMessage(m_hWnd,WM_PING_END, 0, 1);

	nRet = closesocket(rawSocket);
	if (nRet == SOCKET_ERROR)
		WSAError("closesocket()");

}


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

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

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

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

	// 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 */

	if (nRet == SOCKET_ERROR) 
		WSAError("sendto()");
	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

	// Check return value
	if (nRet == SOCKET_ERROR) 
		WSAError("recvfrom()");

	// 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));
}

void CPing::WSAError(LPCSTR lpMsg)
{
	CString strMsg;
	strMsg.Format("%s - WSAError: %ld",lpMsg,WSAGetLastError());	
	::PostMessage(m_hWnd,WM_MSG_STATUS, 0, (LPARAM) AllocBuffer(strMsg));
}




//
// 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 = ~sum;				/* truncate to 16 bits */
	return (answer);
}