Windows网络编程（七）：原始套接字开发

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在调用socket()函数时，如果将第二个参数填为SOCK_RAW，代表创建的是原始套接字类型，第三个参数可以选择IPPROTO_ICMP、IPPROTO_TCP、IPPROTO和IPPROTO_RAW。

#include <winsock2.h>

#pragma comment (lib, "ws2_32")

struct icmp_header
{
	unsigned char icmp_type;    // 消息类型
	unsigned char icmp_code;    // 代码
	unsigned short icmp_checksum;    // 校验和
	unsigned short icmp_id;     // 用来惟一标识此请求的ID号，通常设置为进程ID
	unsigned short icmp_sequence;   // 序列号
	unsigned long icmp_timestamp;   // 时间戳
};

#define ICMP_HEADER_SIZE sizeof(icmp_header)
#define ICMP_ECHO_REQUEST 0x08
#define ICMP_ECHO_REPLY 0x00

// 计算校验和
unsigned short chsum(struct icmp_header *picmp, int len)
{
	long sum = 0;
	unsigned short *pusicmp = (unsigned short *)picmp;

	while (len > 1)
	{
		sum += *(pusicmp++);
		if (sum & 0x80000000)
		{
			sum = (sum & 0xffff) + (sum >> 16);
		}
		len -= 2;
	}

	if (len)
	{
		sum += (unsigned short)*(unsigned char *)pusicmp;
	}

	while (sum >> 16)
	{
		sum = (sum & 0xffff) + (sum >> 16);
	}

	return (unsigned short)~sum;
}

BOOL MyPing(char *szDestIp)
{
	BOOL bRet = TRUE;
	WSADATA wsaData;
	int nTimeOut = 1000;
	char szBuff[ICMP_HEADER_SIZE + 32] = { 0 };
	icmp_header *pIcmp = (icmp_header *)szBuff;
	char icmp_data[32] = { 0 };

	WSAStartup(MAKEWORD(2, 2), &wsaData);
	// 创建原始套接字
	SOCKET s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);

	// 设置接收超时
	setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, (char const*)&nTimeOut, sizeof(nTimeOut));

	// 设置目的地址
	sockaddr_in dest_addr;
	dest_addr.sin_family = AF_INET;
	dest_addr.sin_addr.S_un.S_addr = inet_addr(szDestIp);
	dest_addr.sin_port = htons(0);

	// 构造ICMP封包
	pIcmp->icmp_type = ICMP_ECHO_REQUEST;
	pIcmp->icmp_code = 0;
	pIcmp->icmp_id = (USHORT)::GetCurrentProcessId();
	pIcmp->icmp_sequence = 0;
	pIcmp->icmp_timestamp = 0;
	pIcmp->icmp_checksum = 0;

	// 拷贝数据
	// 这里的数据可以是任意的
	// 这里使用abc是为了和系统提供的看起来一样
	memcpy((szBuff + ICMP_HEADER_SIZE), "abcdefghijklmnopqrstuvwabcdefghi", 32);

	// 计算校验和
	pIcmp->icmp_checksum = chsum((struct icmp_header *)szBuff, sizeof(szBuff));

	sockaddr_in from_addr;
	char szRecvBuff[1024];
	int nLen = sizeof(from_addr);
	sendto(s, szBuff, sizeof(szBuff), 0, (SOCKADDR *)&dest_addr, sizeof(SOCKADDR));
	recvfrom(s, szRecvBuff, MAXBYTE, 0, (SOCKADDR *)&from_addr, &nLen);

	// 判断接收到的是否是自己请求的地址
	if (lstrcmp(inet_ntoa(from_addr.sin_addr), szDestIp))
	{
		bRet = FALSE;
	}
	else
	{
		struct icmp_header *pIcmp1 = (icmp_header *)(szRecvBuff + 20);
		printf("%s\r\n", inet_ntoa(from_addr.sin_addr));
	}

	return bRet;
}

int main(int argc, char **argv)
{
	int i = 0;
	while (i < 1000)
	{
		MyPing("8.8.4.4");
		Sleep(500);
		i++;
	}

	return 0;
}