dnsQueryRaw 函式 (windns.h)

可讓您執行 DNS 查詢，以接受包含 DNS 查詢的原始封包，或查詢名稱和類型。 您可以使用主機系統的設定和組態來增強查詢。

• 您可以將新的查詢選項和自訂伺服器套用至已格式化的原始 DNS 查詢封包。
• 或者，您可以改為提供查詢名稱和類型，並接收剖析的記錄和原始結果封包 (讓客戶端能夠與從伺服器接收的所有資訊互動) 。

查詢會以異步方式執行;和 結果會傳遞至您所實作 DNS_QUERY_RAW_COMPLETION_ROUTINE 異步回呼函式。 若要取消查詢，請呼叫 DnsCancelQueryRaw。

語法

DNS_STATUS DnsQueryRaw(
  DNS_QUERY_RAW_REQUEST *queryRequest,
  DNS_QUERY_RAW_CANCEL  *cancelHandle
);

參數

queryRequest

類型：_In_ DNS_QUERY_RAW_REQUEST*

查詢要求。

cancelHandle

類型：_Inout_ DNS_QUERY_RAW_CANCEL*

用來取得取消句柄，在您需要取消查詢時，您可以傳遞至 DnsCancelQueryRaw 。

傳回值

指出成功或失敗 的DNS_STATUS 值。 如果傳回DNS_REQUEST_PENDING，則當查詢完成時，系統會呼叫您在 queryRequest 的 queryCompletionCallback 成員中傳遞的DNS_QUERY_RAW_COMPLETION_ROUTINE實作。 如果成功，該回呼將會收到查詢的結果，或任何失敗或取消。

備註

原始封包的結構是 RFC 1035 記載的 DNS 查詢和響應的連線表示法。 12 位元組的 DNS 標頭後面接著查詢的問題區段，或 (變數編號 (可以是回應的 0) 記錄。 如果使用 TCP，則原始封包前面必須加上 2 位元組 長度 欄位。 您可以使用此 API 來套用主機 NRPT 規則，或執行加密的 DNS 查詢等等。

範例

範例 1

在此範例中，原始查詢會透過協助程式函式從套接字讀取，而回應會透過相同的套接字傳回。

struct QUERY_RAW_CALLBACK_CONTEXT
{  
    DNS_QUERY_RAW_RESULT    *queryResults;
    HANDLE                  event;
};

VOID
CALLBACK
QueryRawCallback(
    _In_    VOID                  *queryContext,
    _In_    DNS_QUERY_RAW_RESULT  *queryResults
)
{
    QUERY_RAW_CALLBACK_CONTEXT *context = static_cast<QUERY_RAW_CALLBACK_CONTEXT *>(queryContext);

    //
    //  Capture the results of the query. Note that the DNS_QUERY_RAW_RESULT structure needs to
    //  be freed later with DnsQueryRawResultFree.
    //

    context->queryResults = queryResults;   

    SetEvent(context->event);
}

DWORD
HandleDnsQueryFromSocket(
    _In_ SOCKET socket
)
{
    DWORD errorStatus = ERROR_SUCCESS;
    DWORD waitStatus = 0;
    DNS_QUERY_RAW_REQUEST request = {0};
    DNS_QUERY_RAW_CANCEL cancel = {0};
    QUERY_RAW_CALLBACK_CONTEXT context = {0};
    CHAR opaqueSourceAddr[DNS_ADDR_MAX_SOCKADDR_LENGTH];
    ULONG opaqueSourceAddrSize = sizeof(opaqueSourceAddr);

    //
    //  ReceiveDnsQueryBytesFromSocket is a function that reads bytes from a socket
    //  that contains a wire-format DNS query, and gets information about the source
    //  address. It allocates the raw query buffer with HeapAlloc of size
    //  request.dnsQueryRawSize. Note that this function is just an example, and does
    //  not exist in the API.
    //
    errorStatus = ReceiveDnsQueryBytesFromSocket(socket,
                                                 &request.dnsQueryRaw,
                                                 &request.dnsQueryRawSize,
                                                 opaqueSourceAddr,
                                                 opaqueSourceAddrSize);
    if (errorStatus != ERROR_SUCCESS)
    {
        goto Exit;
    }

    context.event = CreateEvent(NULL, FALSE, FALSE, NULL);
    if (context.event == NULL)
    {
        errorStatus = GetLastError();
        goto Exit;
    }

    //
    //  dnsQueryRaw is being used instead of dnsQueryName and dnsQueryType.
    //
    request.dnsQueryName = NULL;
    request.dnsQueryType = 0;

    request.version = DNS_QUERY_RAW_REQUEST_VERSION1; 
    request.resultsVersion = DNS_QUERY_RAW_RESULTS_VERSION1; 
    request.queryOptions = DNS_QUERY_BYPASS_CACHE;
    request.interfaceIndex = 0;
    request.queryCompletionCallback = &QueryRawCallback;
    request.queryContext = &context;
    request.queryRawOptions = 0;
    request.customServersSize = 0;
    request.customServers = NULL;
    request.protocol = DNS_PROTOCOL_UDP;
    memcpy_s(request.maxSa,
             sizeof(request.maxSa),
             opaqueSourceAddr,
             opaqueSourceAddrSize);

    errorStatus = DnsQueryRaw(&request, &cancel);
    if (errorStatus != DNS_REQUEST_PENDING)
    {
        goto Exit;
    }

    waitStatus = WaitForSingleObject(context.event, INFINITE);
    if (waitStatus != WAIT_OBJECT_0)
    {
        errorStatus = GetLastError();
        goto Exit;
    }

    //
    //  SendDnsResponseBytesToSocket is a function that writes a buffer containing a
    //  DNS response to a socket. Depending on the queryStatus, it can send other
    //  messages on the socket to indicate whether the socket should be closed, such as if
    //  the queryStatus indicates an internal DNS failure. Note that this function is
    //  just an example, and does not exist in the API.
    //
    errorStatus = SendDnsResponseBytesToSocket(socket,
                                               context.queryResults->queryStatus,
                                               context.queryResults->queryRawResponse,
                                               context.queryResults->queryRawResponseSize);

Exit:
    if (request.dnsQueryRaw != NULL)
    {
        HeapFree(GetProcessHeap(), 0, request.dnsQueryRaw);
        request.dnsQueryRaw = NULL;
    }

    if (context.queryResults != NULL)
    {
        DnsQueryRawResultFree(context.queryResults);
        context.queryResults = NULL;
    }

    if (context.event != NULL)
    {
        CloseHandle(context.event);
        context.event = NULL;
    }

    return errorStatus;
}

範例 2

在此範例中，查詢會以查詢名稱和類型起始，但接著會以 DnsCancelQueryRaw 取消。

struct QUERY_RAW_CALLBACK_CONTEXT
{
    DNS_QUERY_RAW_RESULT    *queryResults;
    HANDLE                  event;
};

VOID
CALLBACK
QueryRawCallback(
    _In_    VOID                  *queryContext,
    _In_    DNS_QUERY_RAW_RESULT  *queryResults
)
{
    QUERY_RAW_CALLBACK_CONTEXT *context = static_cast<QUERY_RAW_CALLBACK_CONTEXT *>(queryContext);

    //
    //  Capture the results of the query. Note that this structure needs to
    //  be freed later with DnsQueryRawResultFree.
    //

    context->queryResults = queryResults;

    SetEvent(context->event);
}

DWORD
CallDnsQueryRawAndCancel(
    _In_    PWSTR                       queryName,
    _In_    USHORT                      queryType,
    _In_    ULONG                       interfaceIndex,
    _In_    SOCKADDR_INET               *sourceAddr,
    _In_    ULONG                       protocol,
    _In_    DNS_CUSTOM_SERVER           *customServers,
    _In_    ULONG                       customServersSize,
    _Inout_ QUERY_RAW_CALLBACK_CONTEXT  *context
)
{
    DWORD errorStatus = ERROR_SUCCESS;
    DWORD waitStatus = 0;
    DNS_QUERY_RAW_REQUEST request = {0};
    DNS_QUERY_RAW_CANCEL cancel = {0};

    request.version = DNS_QUERY_RAW_REQUEST_VERSION1;
    request.resultsVersion = DNS_QUERY_RAW_RESULTS_VERSION1; 
    request.dnsQueryRawSize = 0;
    request.dnsQueryRaw = NULL;
    request.dnsQueryName = queryName;
    request.dnsQueryType = queryType;
    request.queryOptions = DNS_QUERY_BYPASS_CACHE;
    request.interfaceIndex = interfaceIndex;
    request.queryCompletionCallback = &QueryRawCallback;
    request.queryContext = context;
    request.queryRawOptions = 0;
    request.customServersSize = customServersSize;
    request.customServers = customServers;
    request.protocol = protocol;
    request.sourceAddr = *sourceAddr;

    errorStatus = DnsQueryRaw(&request, &cancel);
    if (errorStatus != DNS_REQUEST_PENDING)
    {
        goto Exit;
    }

    //
    //  Cancel the query with the provided cancel handle.
    //

    errorStatus = DnsCancelQueryRaw(&cancel);
    if (errorStatus != ERROR_SUCCESS)
    {
        goto Exit;
    }

    //
    //  Wait for the callback to indicate that the query has completed. Note that it
    //  is possible for the query to complete successfully or fail for another reason
    //  before the DnsCancelQueryRaw call is made, so the queryStatus member of
    //  DNS_QUERY_RAW_RESULT can be used to determine what happened.
    //

    waitStatus = WaitForSingleObject(context->event, INFINITE);
    if (waitStatus != WAIT_OBJECT_0)
    {
        errorStatus = GetLastError();
        goto Exit;
    }

    errorStatus = context.queryResults->queryStatus;

    if (errorStatus == ERROR_CANCELLED)
    {
        //
	    //  DNS query was successfully cancelled.
	    //
    }	
    else if (errorStatus != ERROR_SUCCESS)
    {
        //
	    //  DNS query failed before it was cancelled.
	    //
    }
    else
    {
        //
	    //  DNS query succeeded before it was cancelled, and can contain valid results.
        //  The other fields of context.queryResults to be processed as in Example 1.
	    //
    }

    //
    //  The context is owned by the caller of this function, and it will be cleaned up there.
    //

Exit:
    return errorStatus;
}

規格需求