C++编写自定义TCP包并发送

转载修改自：
https://blog.csdn.net/e_wsq/article/details/12766443

#include "pch.h"
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#pragma comment(lib,"ws2_32.lib")
#pragma  warning (disable:4996)  //去除安全方法提示

#define IPVER 4
#define MAX_BUFF_LEN 65500

typedef struct ip_hdr
{
	UCHAR h_verlen;
	UCHAR tos;
	USHORT total_len;
	USHORT ident;
	USHORT frag_and_flags;
	UCHAR ttl;
	UCHAR proto;
	USHORT checksum;
	ULONG sourceIP;
	ULONG destIP;
}IP_HEADER;

typedef struct tsd_hdr
{
	ULONG saddr;
	ULONG daddr;
	UCHAR mbz;
	UCHAR ptcl;
	USHORT tcpl;
}PSD_HEADER;

typedef struct tcp_hdr
{
	USHORT th_sport;
	USHORT th_dport;
	ULONG th_seq;
	ULONG th_ack;
	UCHAR th_lenres;
	UCHAR th_flag;
	USHORT th_win;
	USHORT th_sum;
	USHORT th_urp;
}TCP_HEADER;

USHORT checksum(USHORT *buffer, int size)
{
	unsigned long cksum = 0;
	while (size > 1)
	{
		cksum += *buffer++;
		size -= sizeof(USHORT);
	}
	if (size)
	{
		cksum += *(UCHAR*)buffer;
	}

	cksum = (cksum >> 16) + (cksum & 0xffff);
	cksum += (cksum >> 16);
	return (USHORT)(~cksum);
}

int main(int argc, char* argv[])
{
	WSADATA WSAData;
	SOCKET sock;

	IP_HEADER ipHeader;
	TCP_HEADER tcpHeader;
	PSD_HEADER psdHeader;

	char Sendto_Buff[MAX_BUFF_LEN];
	unsigned short check_Buff[MAX_BUFF_LEN];
	const char tcp_send_data[] = { "This is TCP data!" };

	BOOL flag;
	int rect, nTimeOver;

	if (argc != 5)
	{
		printf("Useage: SendTcp soruce_ip source_port dest_ip dest_port \n");

		return false;
	}

	if (WSAStartup(MAKEWORD(2, 2), &WSAData) != 0)
	{
		printf("WSAStartup Error!\n");
		return false;
	}

	if ((sock = WSASocket

	(AF_INET, SOCK_RAW, IPPROTO_IP, NULL, 0, WSA_FLAG_OVERLAPPED))

		== INVALID_SOCKET)
	{
		printf("Socket Setup Error!\n");
		return false;
	}
	flag = true;
	if (setsockopt(sock, IPPROTO_IP, IP_HDRINCL, (char *)&flag, sizeof

	(flag)) == SOCKET_ERROR)
	{
		printf("setsockopt IP_HDRINCL error!\n");
		return false;
	}
	nTimeOver = 1000;
	if (setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char*)&nTimeOver, sizeof(nTimeOver)) == SOCKET_ERROR)
	{
		printf("setsockopt SO_SNDTIMEO error!\n");
		return false;
	}

	ipHeader.h_verlen = (IPVER << 4 | sizeof(ipHeader) / sizeof(unsigned long));

	ipHeader.tos = (UCHAR)0;
	ipHeader.total_len = htons((unsigned short)sizeof(ipHeader) + sizeof

	(tcpHeader)+sizeof(tcp_send_data));
	ipHeader.ident = 0;
	ipHeader.frag_and_flags = 0;
	ipHeader.ttl = 128;
	ipHeader.proto = IPPROTO_TCP;
	ipHeader.checksum = 0;
	ipHeader.sourceIP = inet_addr(argv[1]);
	ipHeader.destIP = inet_addr(argv[3]);

	memset(check_Buff, 0, MAX_BUFF_LEN);
	memcpy(check_Buff, &ipHeader, sizeof(IP_HEADER));
	ipHeader.checksum = checksum(check_Buff, sizeof(IP_HEADER));

	psdHeader.saddr = ipHeader.sourceIP;
	psdHeader.daddr = ipHeader.destIP;
	psdHeader.mbz = 0;
	psdHeader.ptcl = ipHeader.proto;
	psdHeader.tcpl = htons(sizeof(TCP_HEADER) + sizeof(tcp_send_data));

	tcpHeader.th_dport = htons(atoi(argv[4]));
	tcpHeader.th_sport = htons(atoi(argv[2]));
	tcpHeader.th_seq = 0;
	tcpHeader.th_ack = 0;
	tcpHeader.th_lenres = (sizeof(tcpHeader) / sizeof(unsigned long) << 4 | 0);
	tcpHeader.th_flag = 2;

	tcpHeader.th_win = htons((unsigned short)16384);
	tcpHeader.th_urp = 0;
	tcpHeader.th_sum = 0;

	memset(check_Buff, 0, MAX_BUFF_LEN);
	memcpy(check_Buff, &psdHeader, sizeof(psdHeader));
	memcpy(check_Buff + sizeof(psdHeader), &tcpHeader, sizeof(tcpHeader));
	memcpy(check_Buff + sizeof(PSD_HEADER) + sizeof

	(TCP_HEADER), tcp_send_data, sizeof(tcp_send_data));
	tcpHeader.th_sum = checksum(check_Buff, sizeof(PSD_HEADER) + sizeof

	(TCP_HEADER)+sizeof(tcp_send_data));

	memset(Sendto_Buff, 0, MAX_BUFF_LEN);
	memcpy(Sendto_Buff, &ipHeader, sizeof(IP_HEADER));
	memcpy(Sendto_Buff + sizeof(IP_HEADER), &tcpHeader, sizeof

	(TCP_HEADER));
	memcpy(Sendto_Buff + sizeof(IP_HEADER) + sizeof

	(TCP_HEADER), tcp_send_data, sizeof(tcp_send_data));
	int datasize = sizeof(IP_HEADER) + sizeof(TCP_HEADER) + sizeof

	(tcp_send_data);
	SOCKADDR_IN dest;
	memset(&dest, 0, sizeof(dest));
	dest.sin_family = AF_INET;
	dest.sin_addr.s_addr = inet_addr(argv[3]);

	rect = sendto(sock, Sendto_Buff, datasize, 0, (struct sockaddr*)&dest,

		sizeof(dest));
	if (rect == SOCKET_ERROR)
	{
		printf("send error!:%d\n", WSAGetLastError());
		return false;
	}
	else
		printf("send ok!\n");
	closesocket(sock);
	WSACleanup();

	return 0;
}