怎样消除11001#socket错误？

[qiaoqli1978]

利用BCB的socket控件编了一代理程序，当浏览器访问不能被DNS解析的站点时，会弹出以下错误信息：
Windows socket error:不知道这样的主机。（11001）,on API'ASync Lookup'

怎样才能消除上面的情况呢？

[cuilin2002]

是控件吗？什么控件

[qiaoqli1978]

我不能确定一定是BCB的soeket控件的问题，仅仅只是怀疑而已。
楼上的，ServerSocket/ClientSocket

[cuilin2002]

控件一定没问题（我肯定）
那应该是你通讯的问题

[cuilin2002]

把代码粘上来

[wjh1014]

好像当用非阻塞方式时会出现这个问题，要不你先ping一下，通了在联。
关于ping的源码很多的。

[NowCan]

不是代码问题，比如我用Indy控件，如果网络不通就会出这个错误提示。

[qiaoqli1978]

楼上的能否提供一下PING的源码呢？

[wjh1014]

将ping.cpp加入到工程中

//头文件 ping.h

//These defines & structure definitions are taken from the "ipexport.h" and
//"icmpapi.h" header files as provided with the Platform SDK and
//are used internally by the CPing class. Including them here allows
//you to compile the CPing code without the need to have the full
//Platform SDK installed.
#include <winsock.h>

#ifndef __PING_H__
#define __PING_H__
#define max(a, b) (((a) > (b)) ? (a) : (b))

typedef unsigned long IPAddr; // An IP address.

typedef struct tagIP_OPTION_INFORMATION
{
unsigned char Ttl; // Time To Live
unsigned char Tos; // Type Of Service
unsigned char Flags; // IP header flags
unsigned char OptionsSize; // Size in bytes of options data
unsigned char FAR *OptionsData; // Pointer to options data
} IP_OPTION_INFORMATION;

typedef struct tagICMP_ECHO_REPLY
{
IPAddr Address; // Replying address
unsigned long Status; // Reply IP_STATUS
unsigned long RoundTripTime; // RTT in milliseconds
unsigned short DataSize; // Reply data size in bytes
unsigned short Reserved; // Reserved for system use
void FAR *Data; // Pointer to the reply data
IP_OPTION_INFORMATION Options; // Reply options
} ICMP_ECHO_REPLY;

typedef IP_OPTION_INFORMATION FAR* LPIP_OPTION_INFORMATION;
typedef ICMP_ECHO_REPLY FAR* LPICMP_ECHO_REPLY;
typedef HANDLE (WINAPI IcmpCreateFile)(VOID);
typedef IcmpCreateFile* lpIcmpCreateFile;
typedef BOOL (WINAPI IcmpCloseHandle)(HANDLE IcmpHandle);
typedef IcmpCloseHandle* lpIcmpCloseHandle;
typedef DWORD (WINAPI IcmpSendEcho)(HANDLE IcmpHandle, IPAddr DestinationAddress,
LPVOID RequestData, WORD RequestSize,
LPIP_OPTION_INFORMATION RequestOptions,
LPVOID ReplyBuffer, DWORD ReplySize, DWORD Timeout);
typedef IcmpSendEcho* lpIcmpSendEcho;

/////////////////////////// Classes /////////////////////////////////


struct CPingReply
{
in_addr Address; //The IP address of the replier
unsigned long RTT; //Round Trip time in Milliseconds
};

class CPing
{
public:
//Methods
BOOL Ping(LPCTSTR pszHostName, CPingReply& pr, UCHAR nTTL = 10, DWORD dwTimeout = 5000, UCHAR nPacketSize = 32) const;

protected:
BOOL Initialise() const;
static BOOL sm_bAttemptedIcmpInitialise;
static lpIcmpCreateFile sm_pIcmpCreateFile;
static lpIcmpSendEcho sm_pIcmpSendEcho;
static lpIcmpCloseHandle sm_pIcmpCloseHandle;
static BOOL IsSocketReadible(SOCKET socket, DWORD dwTimeout, BOOL& bReadible);
static __int64 sm_TimerFrequency;
};



#endif //__PING_H__

//模块ping.cpp
#include <stdio.h>
#include "ping.h"
#pragma hdrstop

//---------------------------------------------------------------------------
#pragma package(smart_init)

#define MIN_ICMP_PACKET_SIZE 8 //minimum 8 byte icmp packet (just header)
#define MAX_ICMP_PACKET_SIZE 1024 //Maximum icmp packet size

// IP header
typedef struct tagIP_HEADER
{
unsigned int h_len:4; // length of the header
unsigned int version:4; // Version of IP
unsigned char tos; // Type of service
unsigned short total_len; // total length of the packet
unsigned short ident; // unique identifier
unsigned short frag_and_flags; // flags
unsigned char ttl;
unsigned char proto; // protocol (TCP, UDP etc)
unsigned short checksum; // IP checksum
unsigned int sourceIP;
unsigned int destIP;
} IP_HEADER;
typedef IP_HEADER FAR* LPIP_HEADER;

// ICMP header
typedef struct tagICMP_HEADER
{
BYTE i_type;
BYTE i_code; /* type sub code */
USHORT i_cksum;
USHORT i_id;
USHORT i_seq;
/* This is not the std header, but we reserve space for time */
ULONG timestamp;
} ICMP_HEADER;
typedef ICMP_HEADER FAR* LPICMP_HEADER;

void FillIcmpData(LPICMP_HEADER pIcmp, int nData);
BOOL DecodeResponse(char* pBuf, int nBytes, sockaddr_in* from);
USHORT GenerateIPChecksum(USHORT* pBuffer, int nSize);


///////////////////////////////// Macros & Statics ///////////////////////////

#ifdef _DEBUG
//#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

BOOL CPing::sm_bAttemptedIcmpInitialise = FALSE;
lpIcmpCreateFile CPing::sm_pIcmpCreateFile = NULL;
lpIcmpSendEcho CPing::sm_pIcmpSendEcho = NULL;
lpIcmpCloseHandle CPing::sm_pIcmpCloseHandle = NULL;

__int64 CPing::sm_TimerFrequency = 0;


//Internal class which is used to ensure that the ICMP
//handle and winsock stack is closed upon exit
class _CPING
{
public:
_CPING();
~_CPING();
protected:
HINSTANCE sm_hIcmp;

friend class CPing;
};

[wjh1014]

接上
_CPING::_CPING()
{
sm_hIcmp = NULL;
}

_CPING::~_CPING()
{
if (sm_hIcmp) {
FreeLibrary(sm_hIcmp);
sm_hIcmp = NULL;
}
WSACleanup();
}

static _CPING _cpingData;




///////////////////////////////// Implementation //////////////////////////////


BOOL CPing::Initialise() const
{
if (!sm_bAttemptedIcmpInitialise) {
sm_bAttemptedIcmpInitialise = TRUE;

//Initialise the winsock stack
WSADATA wsa;
if (WSAStartup(MAKEWORD(1, 1), &wsa) != 0) {
::MessageBox(NULL,"WinSock版本不匹配","ERROR",MB_OK);
return FALSE;
}

//Load up the ICMP library
_cpingData.sm_hIcmp = LoadLibrary("ICMP.DLL");
if (_cpingData.sm_hIcmp == NULL) {
::MessageBox(NULL,"无法载入'ICMP.DLL'","ERROR",MB_OK);
return FALSE;
}

//Retrieve pointers to the functions in the ICMP dll
sm_pIcmpCreateFile = (lpIcmpCreateFile) GetProcAddress(_cpingData.sm_hIcmp,"IcmpCreateFile");
sm_pIcmpSendEcho = (lpIcmpSendEcho) GetProcAddress(_cpingData.sm_hIcmp,"IcmpSendEcho" );
sm_pIcmpCloseHandle = (lpIcmpCloseHandle) GetProcAddress(_cpingData.sm_hIcmp,"IcmpCloseHandle");
if (sm_pIcmpCreateFile == NULL || sm_pIcmpSendEcho == NULL ||
sm_pIcmpCloseHandle == NULL)
::MessageBox(NULL,"'ICMP.DLL'中函数无效","ERROR",MB_OK);
}

return (sm_pIcmpCreateFile != NULL && sm_pIcmpSendEcho != NULL &&
sm_pIcmpCloseHandle != NULL);
}


BOOL CPing::IsSocketReadible(SOCKET socket, DWORD dwTimeout, BOOL& bReadible)
{
timeval timeout = {dwTimeout/1000, dwTimeout % 1000};
fd_set fds;
FD_ZERO(&fds);
FD_SET(socket, &fds);
int nStatus = select(0, &fds, NULL, NULL, &timeout);
if (nStatus == SOCKET_ERROR) {
return FALSE;
}
else {
bReadible = !(nStatus == 0);
return TRUE;
}
}

BOOL CPing::Ping(LPCTSTR pszHostName, CPingReply& pr, UCHAR nTTL, DWORD dwTimeout, UCHAR nPacketSize) const
{
//Make sure everything is initialised
if (!Initialise())
return FALSE;

LPSTR lpszAscii = (LPTSTR) pszHostName;
//Convert from dotted notation if required
unsigned long addr = inet_addr(lpszAscii);
if (addr == INADDR_NONE) {
//Not a dotted address, then do a lookup of the name
hostent* hp = gethostbyname(lpszAscii);
if (hp)
memcpy(&addr, hp->h_addr, hp->h_length);
else {
char msg[64];
sprintf(msg,"无法解析主机名：%s",pszHostName);
::MessageBox(NULL,msg,"ERROR",MB_OK);
return FALSE;
}
}

//Create the ICMP handle
HANDLE hIP = sm_pIcmpCreateFile();
if (hIP == INVALID_HANDLE_VALUE) {
::MessageBox(NULL,"无效的'ICMP'句柄","ERROR",MB_OK);
return FALSE;
}

//Set up the option info structure
IP_OPTION_INFORMATION OptionInfo;
ZeroMemory(&OptionInfo, sizeof(IP_OPTION_INFORMATION));
OptionInfo.Ttl = nTTL;

//Set up the data which will be sent
unsigned char* pBuf = new unsigned char[nPacketSize];
memset(pBuf, 'E', nPacketSize);

//Do the actual Ping
int nReplySize = sizeof(ICMP_ECHO_REPLY) + max(MIN_ICMP_PACKET_SIZE, nPacketSize);
unsigned char* pReply = new unsigned char[nReplySize];
ICMP_ECHO_REPLY* pEchoReply = (ICMP_ECHO_REPLY*) pReply;
DWORD nRecvPackets = sm_pIcmpSendEcho(hIP, addr, pBuf, nPacketSize, &OptionInfo, pReply, nReplySize, dwTimeout);

//Check we got the packet back
BOOL bSuccess = (nRecvPackets == 1);

//Check the IP status is OK (O is IP Success)
if (bSuccess && (pEchoReply->Status != 0)) {
bSuccess = FALSE;
SetLastError(pEchoReply->Status);
}

//Check we got the same amount of data back as we sent
if (bSuccess) {
bSuccess = (pEchoReply->DataSize == nPacketSize);
if (!bSuccess)
SetLastError(ERROR_UNEXP_NET_ERR);
}

//Check the data we got back is what was sent
if (bSuccess) {
char* pReplyData = (char*) pEchoReply->Data;
for (int i=0; i<nPacketSize && bSuccess; i++)
bSuccess = (pReplyData[i] == 'E');

if (!bSuccess)
SetLastError(ERROR_UNEXP_NET_ERR);
}

//Close the ICMP handle
sm_pIcmpCloseHandle(hIP);

if (bSuccess) {
//Ping was successful, copy over the pertinent info
//into the return structure
pr.Address.S_un.S_addr = pEchoReply->Address;
pr.RTT = pEchoReply->RoundTripTime;
}

//Free up the memory we allocated
delete [] pBuf;
delete [] pReply;

//return the status
return bSuccess;
}


在程序中加入如下代码判断
CPingReply reply;
CPing PingHost;
// 先PING主机，检测网络是否畅通 //old is 64,4000,32
bool rtn = PingHost.Ping("RemoteHost",reply,128,2000,32);
if(!rtn){
Message="错误：通讯线路故障！";
Result=-1;
Close();
return;
}

RemoteHost为在hosts文件中定义的远程主机名字。