我怎樣才能使用Pcap.net進行mDNS查詢？

Question

問題：我正在尋找一個mDNS數據包，同時搜索stackflow的選項。我嘗試了Bonjour和一些包裝，但成功非常有限，尤其是當我第二次請求並獲得套接字綁定投訴時（當然，這可能是我的代碼而不是它們）。

由於VB.net沒有我知道的真正可編輯的dnsquery，我在pcapdotnet中使用構建DNS數據包中的DNS層，並且只是逐層製作數據包。我認爲這是一個很好的選擇，但我有點失落，我會怎麼做。

下面是我們想要的問題：

 q_name = new QuestionName("_axis-video._tcp.local"), 
     q_type = QuerryConstants.Question.QuestionType.PTR, 
     q_class = QuerryConstants.Question.QuestionClass.IN 

下面是從他們的標準我的編輯BuildDNSPacket功能：

Private Shared Function BuildDnsPacket(destmac As String, domainName As String) As Packet 

    'get source MAC address of PC 
    Dim nic = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces() 
    Dim source As String = nic(0).GetPhysicalAddress().ToString 
    Dim sourcearray As Byte() = System.Text.Encoding.ASCII.GetBytes(source) 

    'format 
    Dim sourceMacStr As String = "" 
    For i As Integer = 0 To sourcearray.Count - 1 Step 2 
     sourceMacStr += Chr(sourcearray(i)) & Chr(sourcearray(i + 1)) & ":" 
    Next 


    ' Will be filled automatically. 
    Dim ethernetLayer As New EthernetLayer() With { _ 
     .Source = New MacAddress(sourceMacStr.Substring(0, 17)), _ 
      .Destination = New MacAddress(destmac), _ 
      .EtherType = EthernetType.None _ 
    } 

    ' Will be filled automatically. 
    Dim ipV4Layer As New IpV4Layer() With { _ 
      .Source = New IpV4Address("1.2.3.4"), _ 
      .CurrentDestination = New IpV4Address(destmac), _ 
      .Fragmentation = IpV4Fragmentation.None, _ 
      .HeaderChecksum = Nothing, _ 
      .Identification = 123, _ 
      .Options = IpV4Options.None, _ 
      .Protocol = Nothing, _ 
      .Ttl = 100, _ 
      .TypeOfService = 0 _ 
    } 

    ' Will be filled automatically. 
    Dim udpLayer As New UdpLayer() With { _ 
      .SourcePort = 5353, _ 
      .DestinationPort = 5353, _ 
      .Checksum = Nothing, _ 
      .CalculateChecksumValue = False _ 
    } 

    Dim dnsLayer As New DnsLayer() With { _ 
      .Id = 0, _ 
      .IsResponse = False, _ 
      .OpCode = DnsOpCode.Query, _ 
      .IsAuthoritativeAnswer = False, _ 
      .IsTruncated = False, _ 
      .IsRecursionDesired = False, _ 
      .IsRecursionAvailable = False, _ 
      .FutureUse = False, _ 
      .IsAuthenticData = False, _ 
      .IsCheckingDisabled = False, _ 
      .ResponseCode = DnsResponseCode.NoError, _ 
      .Queries = {New DnsQueryResourceRecord(New DnsDomainName(domainName), DnsType.Ptr, DnsClass.Any)}, _ 
      .Answers = Nothing, _ 
      .Authorities = Nothing, _ 
      .Additionals = Nothing, _ 
      .DomainNameCompressionMode = DnsDomainNameCompressionMode.All _ 
    } 


    Dim builder As New PacketBuilder(ethernetLayer, ipV4Layer, udpLayer, dnsLayer) 

    Return builder.Build(DateTime.Now) 
End Function 

的主要區別是我改變DnsType爲PTR和端口5353

問題：我還需要添加或更改哪些內容才能使其成爲mDNS？我可以將什麼放入域名？我應該改變dnsclass嗎？

絕對歡迎所有或任何建議。

Answer 1

我回答我的情況下，其他人誰需要做在vb.net的mDNS問題需要這樣的：

解決方案：我並不需要任何東西添加到DNS層，使這項工作。我改變了DNS層以下：

Dim dnsLayer As New DnsLayer() With { _ 
      .Id = 0, _ 
      .IsResponse = False, _ 
      .OpCode = DnsOpCode.Query, _ 
      .IsAuthoritativeAnswer = False, _ 
      .IsTruncated = False, _ 
      .IsRecursionDesired = False, _ 
      .IsRecursionAvailable = False, _ 
      .FutureUse = False, _ 
      .IsAuthenticData = False, _ 
      .IsCheckingDisabled = False, _ 
      .ResponseCode = DnsResponseCode.NoError, _ 
      .Queries = {New DnsQueryResourceRecord(New DnsDomainName(domainName), DnsType.Ptr, DnsClass.Any)}, _ 
      .Answers = Nothing, _ 
      .Authorities = Nothing, _ 
      .Additionals = Nothing, _ 
      .DomainNameCompressionMode = DnsDomainNameCompressionMode.All _ 
    } 

我做了IPv4層裏的輸出地址是組播地址「224.0.0.251」，改變了我的端口5353，並使用問題的域名我列在上面。

下面是一個wireshark來顯示回覆：