解析IP报头VB.NET中的UDP报头

Imports System.Net
Imports System.Net.Sockets

Module Program
    Sub Main()
        Dim udpClient As New UdpClient()
        Dim ipAddress As IPAddress = IPAddress.Parse("192.168.0.1") ' 设置目标IP地址
        Dim port As Integer = 1234 ' 设置目标端口号

        udpClient.Connect(ipAddress, port)
        Dim udpData As Byte() = udpClient.Receive()

        ' 解析IP报头
        Dim ipHeader As New IPHeader(udpData)

        ' 解析UDP报头
        Dim udpHeader As New UDPHeader(ipHeader.Data)

        ' 输出解析结果
        Console.WriteLine("源IP地址: " & ipHeader.SourceAddress.ToString())
        Console.WriteLine("目标IP地址: " & ipHeader.DestinationAddress.ToString())
        Console.WriteLine("协议类型: " & ipHeader.Protocol.ToString())
        Console.WriteLine("数据包长度: " & ipHeader.TotalLength.ToString())
        Console.WriteLine("源端口号: " & udpHeader.SourcePort.ToString())
        Console.WriteLine("目标端口号: " & udpHeader.DestinationPort.ToString())
        Console.WriteLine("数据长度: " & udpHeader.Length.ToString())

        udpClient.Close()
    End Sub
End Module

' IP报头类
Public Class IPHeader
    Public Version As Byte
    Public HeaderLength As Byte
    Public TypeOfService As Byte
    Public TotalLength As UShort
    Public Identification As UShort
    Public Flags As UShort
    Public FragmentOffset As UShort
    Public TimeToLive As Byte
    Public Protocol As Byte
    Public Checksum As UShort
    Public SourceAddress As IPAddress
    Public DestinationAddress As IPAddress
    Public Data As Byte()

    Public Sub New(packet As Byte())
        Version = packet(0) >> 4
        HeaderLength = (packet(0) And 15) * 4
        TypeOfService = packet(1)
        TotalLength = BitConverter.ToUInt16(packet, 2)
        Identification = BitConverter.ToUInt16(packet, 4)
        Flags = BitConverter.ToUInt16(packet, 6)
        FragmentOffset = BitConverter.ToUInt16(packet, 8)
        TimeToLive = packet(9)
        Protocol = packet(10)
        Checksum = BitConverter.ToUInt16(packet, 12)
        SourceAddress = New IPAddress(BitConverter.ToUInt32(packet, 12))
        DestinationAddress = New IPAddress(BitConverter.ToUInt32(packet, 16))
        Data = New Byte(packet.Length - HeaderLength - 1) {}
        Array.Copy(packet, HeaderLength, Data, 0, packet.Length - HeaderLength)
    End Sub
End Class

' UDP报头类
Public Class UDPHeader
    Public SourcePort As UShort
    Public DestinationPort As UShort
    Public Length As UShort
    Public Checksum As UShort
    Public Data As Byte()

    Public Sub New(packet As Byte())
        SourcePort = BitConverter.ToUInt16(packet, 0)
        DestinationPort = BitConverter.ToUInt16(packet, 2)
        Length = BitConverter.ToUInt16(packet, 4)
        Checksum = BitConverter.ToUInt16(packet, 6)
        Data = New Byte(packet.Length - 7) {}
        Array.Copy(packet, 8, Data, 0, packet.Length - 8)
    End Sub
End Class