用原始套接字监听局域网内的数据包

				用原始套接字监听局域网内的数据包，解析IP头内的目的IP出现问题
				
				用原始套接字监听局域网内的数据包，为什么只能得到ip头内的源IP地址而目的IP地址总是会等于源IP地址？？     
				奇怪了为什么就是不能得到目的IP地址？？
				
				
				#include "stdafx.h"
				#include ; 
				#include ; 
				#include ; 
				#include ;
				#pragma  comment(lib,"Ws2_32")
				#define MAX_PACK_LEN    1024
				typedef struct ip_hdr //定义IP首部 
				{ 
				unsigned char h_lenver; //4位首部长度,4位IP版本号 
				unsigned char tos; //8位服务类型TOS 
				unsigned short total_len; //16位总长度（字节） 
				unsigned short ident; //16位标识 
				unsigned short th_flag; //3位标志位 
				unsigned char ttl; //8位生存时间 TTL 
				unsigned char iProtocol; //8位协议 (TCP, UDP 或其他) 
				unsigned short checksum; //16位IP首部校验和 
				unsigned int sourceIP; //32位源IP地址 
				unsigned int destIP; //32位目的IP地址 
				}IP_HEADER; 
				
				void DeCodeIP(char *buf,int iBufSize)  //解析侦听到的IP数据包
				
				{
				
				   IP_HEADER * pIPhdr;
				
				  pIPhdr=(IP_HEADER * )buf;
				        
				  sockaddr_in dest,src;
				  
				  dest.sin_family=AF_INET;
				  dest.sin_addr.S_un.S_addr=pIPhdr->;destIP;
				  src.sin_family=AF_INET;
				  src.sin_addr.S_un.S_addr=pIPhdr->;sourceIP;
				  char *lpdest=inet_ntoa(dest.sin_addr);
				  char *lpsrc=inet_ntoa(src.sin_addr);
				  printf("dest:%s,src:%s\n",lpdest,lpsrc);
				
				} 
				int main(int argc, char* argv[])
				{
				        int iErrorCode;
				
				char RecvBuf[MAX_PACK_LEN];
				
				WSADATA wsaData;
				
				iErrorCode = WSAStartup(MAKEWORD(2,2),&wsaData);
				
				SOCKET SockRaw = WSASocket(AF_INET, SOCK_RAW, IPPROTO_IP, NULL, 0, WSA_FLAG_OVERLAPPED);
				
				SOCKADDR_IN sa;
				
				sa.sin_family = AF_INET;
				
				sa.sin_port = htons(6000);
				
				sa.sin_addr.S_un.S_addr=inet_addr("192.168.0.1");
				
				
				
				if(bind(SockRaw, (PSOCKADDR)&sa, sizeof(sa))!=0)
				{
				        printf("bind error!");
				        WSACleanup();
				}
				
				
				DWORD dwBufferLen[10] ;
				
				DWORD dwBufferInLen=1;
				
				DWORD dwBytesReturned=0;
				
				iErrorCode=WSAIoctl(SockRaw, SIO_RCVALL,&dwBufferInLen, sizeof(dwBufferInLen), 
				
				NULL, 0,&dwBytesReturned , NULL , NULL );//设置网卡为混杂模式以监听流过网卡的数据包
				if(iErrorCode==SOCKET_ERROR)
				{
				        printf("ioctl error!");
				        WSACleanup();
				}
				
				
				while(1)
				
				{
				
				        memset(RecvBuf, 0, sizeof(RecvBuf));
				        iErrorCode = recv(SockRaw, RecvBuf, sizeof(RecvBuf),0);
				        if(iErrorCode!=SOCKET_ERROR&&iErrorCode>;20)
				        DeCodeIP(RecvBuf, iErrorCode);
				
				}
				
				        return 0;
				}