【网络编程】之十三、ping程序实现

使用原始套接字：SOCK_RAW
需要ICMP
代码如下：
#include<iostream>

#include<WinSock2.h>

using namespace std;

#pragma comment(lib, "WS2_32.lib")

typedef struct icmp_hdr{

	unsigned char icmp_type;

	unsigned char icmp_code;

	unsigned short icmp_checksum;

	unsigned short icmp_id;

	unsigned short icmp_sequence;

	unsigned long icmp_timnestamp;

}ICMP_HDR, *PICMP_HDR;

typedef struct _IPHeader{

	UCHAR iphVerLen;

	UCHAR ipTOS;

	USHORT ipLength;

	USHORT ipID;

	USHORT ipFlags;

	UCHAR ipTTL;

	UCHAR ipProtocol;

	USHORT ipChecksum;

	ULONG ipSource;

	ULONG ipDestination;

}IPHeader, *PIPHeader;

USHORT checksum(USHORT* buffer, int size)

{

	unsigned long cksum = 0;

	while(size > 1)

	{

		cksum += *buffer++;

		size -= sizeof(USHORT);

	}

	// 奇数，将最后一个字节扩展到双字， 再累加

	if(size)

		cksum += *(UCHAR*)buffer;

	//高16  低16相加，取反

	cksum = (cksum >> 16) + (cksum & 0xffff);

	cksum += (cksum >> 16);

	return (USHORT)(~cksum);

}

int main(void)

{

	char szDestIp[] = "127.0.0.1";

	SOCKET sRaw= ::socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);

	//SetTimeout(sRaw, 1000, TRUE);

	SOCKADDR_IN dest;

	dest.sin_family = AF_INET;

	dest.sin_port = htons(5674);

	dest.sin_addr.S_un.S_addr = inet_addr(szDestIp);

	char buff[sizeof(ICMP_HDR) + 32];

	ICMP_HDR *pIcmp = (ICMP_HDR*)buff;

	pIcmp->icmp_type = 8;

	pIcmp->icmp_code = 0;

	pIcmp->icmp_id = (USHORT)::GetCurrentProcess();

	pIcmp->icmp_checksum = 0;

	pIcmp->icmp_sequence = 0;

	memset(&buff[sizeof(ICMP_HDR)], 'E', 32);

	//发送

	USHORT nSeq = 0;

	char recvBuf[1024];

	SOCKADDR_IN from;

	int nLen = sizeof(from);

	while(TRUE)

	{

		static int nCount = 0;

		int nRet;

		if(nCount++ == 4)

			break;

		pIcmp->icmp_checksum = 0;

		pIcmp->icmp_timnestamp = ::GetTickCount();

		pIcmp->icmp_sequence = nSeq++;

		pIcmp->icmp_checksum = checksum((USHORT*)buff, sizeof(ICMP_HDR) + 32);

		nRet = ::sendto(sRaw, buff, sizeof(ICMP_HDR) + 32, 0, (SOCKADDR*)&dest, sizeof(dest));

		if(nRet == SOCKET_ERROR)

		{

			cout << "sendto error:" << ::WSAGetLastError() << endl;

			return -1;

		}

		nRet = ::recvfrom(sRaw, recvBuf, 1024, 0, (sockaddr*)&from, &nLen);

		if(nRet == SOCKET_ERROR)

		{

			if(::WSAGetLastError() == WSAETIMEDOUT)

			{

				cout << "time out" << endl;

				continue;

			}

			cout << "recvfrom failed:" << ::WSAGetLastError() << endl;

			return -1;

		}

		//解析

		int nTick = ::GetTickCount();

		if(nRet < sizeof(IPHeader) + sizeof(ICMP_HDR))

		{

			cout << "Too few bytes from " << ::inet_ntoa(from.sin_addr) << endl;

		}

		ICMP_HDR *pRecvIcmp = (ICMP_HDR*)(recvBuf + sizeof(IPHeader));

		if(pRecvIcmp->icmp_type != 0)

		{

			cout << "nonecho type " << pRecvIcmp->icmp_type << " recvd" << endl;

			return -1;

		}

		if(pRecvIcmp->icmp_id != ::GetCurrentProcessId())

		{

			cout << "someone ele's packet!" << endl;

			return -1;

		}

		cout << nRet << " bytes from " << inet_ntoa(from.sin_addr) ;

		cout << "icmp_seq = " << pRecvIcmp->icmp_sequence ;

		cout << "time: " << nTick - pRecvIcmp->icmp_timnestamp << " ms";

		cout << endl;

		Sleep(1000);

	}

	return 0;

}
jofranks 13.7.24 于南昌
巴特西

【网络编程】之十三、ping程序实现

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