本文实例讲述了C++实现ping程序的方法。分享给大家供大家参考。具体实现方法如下：
该实例涉及ICMP数据包的发送与回显，PING程序代码如下：
{
CInitSock initSock;
HWND hWnd = (HWND)lParam; //从参数得到句柄
char szIp[64] ={0};
::GetDlgItemTextA(hWnd, IDC_IP, szIp, sizeof(szIp)); //从控件得到ip地址
//1. 创建协议类型为IPPROTO_ICMP的原始套接字，设置套接字属性
SOCKET sRaw = ::socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
SetTimeOut(sRaw, 1000, TRUE);
//2.创建并初始化ICMP封包
char buff[sizeof(ICMP_HDR)+32] = {0};
ICMP_HDR* pIcmp = (ICMP_HDR*)buff;
pIcmp->icmp_type = 8;
pIcmp->icmp_code = 0;
pIcmp->icmp_checksum = 0;
pIcmp->icmp_id = (USHORT)::GetCurrentProcessId();
pIcmp->icmp_sequence = 0;
pIcmp->icmp_timestamp = 0;
//填充数据
memset(&buff[sizeof(ICMP_HDR)], 'E', 32);
//开始发送和接收封包
USHORT nSeq = 0;
SOCKADDR_IN dest;
dest.sin_family = AF_INET;
dest.sin_port = htons(0);
dest.sin_addr.S_un.S_addr = inet_addr(szIp); //inet_addr("192.168.19.63"); //inet_addr(szIp);220.181.111.147
CString strToShow="";
char* pszRevBuf = new char[1024]; //[1024] = {0};
memset(pszRevBuf, 0, 1024);
SOCKADDR_IN from;
int nFromLen= sizeof(from);
while (TRUE)
{
//3. 调用sendto发送ICMP请求
static int nCount=0;
if (nCount++==4)
{
break;
}
pIcmp->icmp_checksum = checksum((USHORT*)buff, sizeof(ICMP_HDR)+32);
pIcmp->icmp_sequence = ++nSeq;
pIcmp->icmp_timestamp = ::GetTickCount();
int nRet;
nRet = ::sendto(sRaw, buff, sizeof(ICMP_HDR)+32, 0, (SOCKADDR*)&dest, sizeof(dest));
if (nRet == SOCKET_ERROR)
{
int nError = ::WSAGetLastError();
strToShow += "sendto error\r\n";
return -1;
}
//4. 调用recvfrom接受ICMP响应
nRet = ::recvfrom(sRaw, pszRevBuf, 1024, 0, (sockaddr*)&from, &nFromLen);
if (nRet == SOCKET_ERROR)
{
if (::WSAGetLastError() == WSAETIMEDOUT)
{
strToShow += "timeout\r\n";
continue;
}
strToShow += "recvfrom error\r\n";
return -1;
}
//解析接收到的ICMP包
int nTick = ::GetTickCount();
if (nRet < sizeof(ICMP_HDR)+sizeof(IPHeader))
{
strToShow += "less byte recved..\r\n";
}
ICMP_HDR* pRecvIcmp = (ICMP_HDR*)(pszRevBuf + sizeof(IPHeader));// 跳过IP头
if (pRecvIcmp->icmp_type != 0)
{
strToShow += "不是回显类型";
return -1;
}
if (pRecvIcmp->icmp_id != ::GetCurrentProcessId())
{
strToShow += "不是本进程的回显包\r\n";
return -1;
}
CString strTemp;
strTemp.Format("收到来自于[%s]IP的%04d字节\r\n", inet_ntoa(from.sin_addr), nRet);
strToShow += strTemp;
strTemp = "";
strTemp.Format("序列号:%d\r\n", pRecvIcmp->icmp_sequence);
strToShow += strTemp;
strTemp = "";
strTemp.Format("花费时间:%d\r\n", nTick - pRecvIcmp->icmp_timestamp);
}
strToShow += "**********************************";
::SetDlgItemTextA(hWnd, IDC_DATA, strToShow);
return 0;
}</div>
IP头和ICMP头代码如下：
{
unsigned long cksum=0;
//将数据以字为单位加到cksum
while (nSize > 1)
{
cksum += *buff++;
nSize -= sizeof(USHORT);
}
//如果为奇数, 将最后一个字扩展到双字，再累加
if (nSize)
{
cksum += *(UCHAR*)buff;
}
//将cksum的高16位与低16位相加，取反后得到校验和
cksum = (cksum>>16) + (cksum & 0xffff);
cksum += (cksum>>16);
return (USHORT)(~cksum);
}
BOOL SetTimeOut(SOCKET s, int nTime, BOOL bRecv)
{
int ret = ::setsockopt(s, SOL_SOCKET, bRecv?SO_RCVTIMEO:SO_SNDTIMEO, (char*)&nTime, sizeof(nTime));
return ret!=SOCKET_ERROR;
}
typedef struct icmp_hdr
{
unsigned char icmp_type;
unsigned char icmp_code;
unsigned short icmp_checksum;
//下面是回显头
unsigned short icmp_id;
unsigned short icmp_sequence;
unsigned long icmp_timestamp;
}ICMP_HDR, *PICMP_HDR;
typedef struct _IPHeader
{
UCHAR iphVerLen;
UCHAR ipTOS;
USHORT ipLength;
USHORT ipID;
USHORT ipFlag;
UCHAR ipTTL;
UCHAR ipProtocol;
USHORT ipCheckSum;
ULONG ipSource;
ULONG ipDestination;
}IPHeader, *PIPHeader;</div>
希望本文所述对大家的C++程序设计有所帮助。
</div>