使用 ICMP 和 RAW Sockets实现 ping 类

//
// PING.CPP -- Ping program using ICMP and RAW Sockets
//

#include "ping.h"
#pragma comment(lib, "ws2_32.lib")

CPing::CPing()
{
bInitWinSockOK = false;

// Init WinSock
WSADATA wsaData;
WORD wVersionRequested = MAKEWORD(1,1);
if ( WSAStartup(wVersionRequested, &wsaData) )
{
Report("/nError initializing WinSock/n");
}
else if (wsaData.wVersion != wVersionRequested)// Check version
{
Report("/nWinSock version not supported/n");
}
else
{
bInitWinSockOK = true;
}
}

CPing::~CPing()
{
if(bInitWinSockOK)
WSACleanup();// Free WinSock
}

// ping()
// Calls SendEchoRequest() and
// RecvEchoReply() and retport results
void CPing::ping(LPCSTR pstrHost)
{
SOCKET	  rawSocket;
LPHOSTENT lpHost;
struct    sockaddr_in saDest;
struct    sockaddr_in saSrc;
DWORD	  dwTimeSent;
DWORD	  dwElapsed;
u_char    cTTL;
int       nLoop;
int       nRet;

if(!bInitWinSockOK)
{
Report("/nWinSock must be initializing/n");
return;
}

// Create a Raw socket
rawSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if (rawSocket == SOCKET_ERROR)
{
Report("socket() error: %d/n", WSAGetLastError());
return;
}

// Lookup host
lpHost = gethostbyname(pstrHost);
if (lpHost == NULL)
{
Report("/nHost not found: %s/n", pstrHost);
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
Report("/nPinging %s [%s] with %d bytes of data:/n",
pstrHost,
inet_ntoa(saDest.sin_addr),
REQ_DATASIZE);

// Ping multiple times
for (nLoop = 0; nLoop < 4; nLoop++)
{
// Send ICMP echo request
SendEchoRequest(rawSocket, &saDest);

// Use select() to wait for data to be received
nRet = WaitForEchoReply(rawSocket);
if (nRet == SOCKET_ERROR)
{
Report("select() error: %d/n", WSAGetLastError());
break;
}
if (!nRet)
{
Report("/nTimeOut");
break;
}

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

// Calculate elapsed time
dwElapsed = GetTickCount() - dwTimeSent;
Report("/nReply from: %s: bytes=%d time=%ldms TTL=%d",
inet_ntoa(saSrc.sin_addr),
REQ_DATASIZE,
dwElapsed,
cTTL);
}
Report("/n");
nRet = closesocket(rawSocket);
if (nRet == SOCKET_ERROR)
Report("closesocket() error: %d/n", WSAGetLastError());
}

void CPing::Report(LPCSTR format, ...)
{
char _Buff[8192];
memset(_Buff, 0, sizeof(_Buff));

va_list arg;
va_start(arg, format);
int charSize = _vsnprintf(_Buff, sizeof(_Buff), format, arg);
va_end(arg);

OutputDebugStringA(_Buff);
}

//
//  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);
}

// SendEchoRequest()
// Fill in echo request header
// and send to destination
int CPing::SendEchoRequest(SOCKET s,LPSOCKADDR_IN lpstToAddr)
{
static ECHOREQUEST echoReq;
static u_short nId = 1;
static u_short 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)
Report("sendto() error: %d/n", WSAGetLastError());
return (nRet);
}

// RecvEchoReply()
// Receive incoming data
// and parse out fields
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)
Report("recvfrom() error: %d/n", WSAGetLastError());

// return time sent and IP TTL
*pTTL = echoReply.ipHdr.TTL;
return(echoReply.echoRequest.dwTime);
}

// WaitForEchoReply()
// Use select() to determine when
// data is waiting to be read
int CPing::WaitForEchoReply(SOCKET s)
{
struct timeval Timeout;
fd_set readfds;

readfds.fd_count = 1;
readfds.fd_array[0] = s;
Timeout.tv_sec = 5;
Timeout.tv_usec = 0;

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

//test code
CPing ping;
ping.ping( "www.sina.com.cn" );

//output
Pinging www.sina.com.cn [61.172.201.194] with 32 bytes of data:

Reply from: 61.172.201.194: bytes=32 time=15ms TTL=249
Reply from: 61.172.201.194: bytes=32 time=16ms TTL=249
Reply from: 61.172.201.194: bytes=32 time=0ms TTL=249
Reply from: 61.172.201.194: bytes=32 time=15ms TTL=249