C# 如何构造UDP数据包但不发送它
这是一个奇怪的要求 我有一个字节数组，需要使用C#通过串口发送到另一个设备。然而，我需要首先将字节数组包装在udp数据包中，但同样，它将通过串行端口发送，而不是通过udp发送。有没有办法将udp数据包构造为字节数组，然后通过串行端口发送C# 如何构造UDP数据包但不发送它,c#,serial-port,udp,C#,Serial Port,Udp,这是一个奇怪的要求 我有一个字节数组，需要使用C#通过串口发送到另一个设备。然而，我需要首先将字节数组包装在udp数据包中，但同样，它将通过串行端口发送，而不是通过udp发送。有没有办法将udp数据包构造为字节数组，然后通过串行端口发送 我以前使用udp发送和接收过消息，但从未在udp数据包被构造而不是通过udp发送的地方发送过消息。我想我在.NET中的UdpClient中没有看到任何实际的数据包级别的类的原因是，坦率地说，它非常简单，因为它是一个无连接/无状态的协议 您应该通过创建包含标准U
我以前使用udp发送和接收过消息，但从未在udp数据包被构造而不是通过udp发送的地方发送过消息。我想我在.NET中的
UdpClient您应该通过创建包含标准UDP数据包中所有数据的UDP类来构造UDP数据包 数据如下： 源端口[SP]（16位）：当尝试连接或正在进行连接时，这将指定本地计算机等待侦听目标计算机响应的端口 目标端口[DP]（16位）：当用户希望连接到远程机器上的服务时，应用层程序指定初始连接应使用的端口。当不是作为初始连接的一部分时，这将指定当数据包被发送到其目的地时，远程机器将使用的端口号 长度[Len]（16位）：这允许接收站知道有多少输入位应该是有效数据包的一部分。长度是计算UDP数据包中包含多少字节（包括报头中的字节）的计算。由于UDP在报头中始终有4个字段，每个字段有16位，并且数据/负载长度可变，因此我们知道长度将为8+（负载中的字节数） UDP校验和[UDPCS]（16位）：这是一种校验和，覆盖UDP数据包的报头和数据部分，以允许接收主机验证传入UDP数据包的完整性。UDP数据包在校验和字段中加载一个预定义的数字，然后在计算校验和时，将校验和写入上一个值。当数据包到达目的地时，目的地机器的操作系统查看4报头字段（由位16到31组成的字节）并将其从数据包中取出，然后在校验和字段中没有任何内容的情况下重新计算数据包的校验和。然后，操作系统将计算出的校验和与数据包中传输的校验和进行比较。如果校验和相同，则数据可以正常传输，但如果存在差异，UDP数据包和数据将被丢弃，并且接收机器不会尝试获取新副本，发送机器也不会尝试发送相同的数据包。这个包永远丢失了。UDP不可靠！有关可靠的传输层TCP/IP套件协议，请参阅TCP数据包 数据（可变位）：如您所料，这是有效负载，或UDP数据包的数据部分。有效负载可以是任意数量的协议（通常是应用层）。一些最常用的UDP协议包括NFS、DNS以及多音频和视频流协议。如果UDP数据包中发生错误，并且需要修复错误，则由应用层查找错误并请求其应用层的“大块”或“块”数据 创建一个包含所有这些数据并适当填充的类时，会重载
ToString希望这有帮助。我将接受Yochai的回答，因为该链接（以及该站点中的其他页面）提供了构建udp数据包和ip报头的代码。对于其他试图实现此目标的人，以下是代码： 如何称呼它：
var udpPacketBytes = UDPPacket.Construct(IPAddress.Parse("1.1.1.1"), 1000, IPAddress.Parse("2.2.2.2"), 6100, payloadBytes);
public static class UDPPacket
{
public static byte[] Construct(IPAddress sourceAddress, ushort sourcePort, IPAddress destinationAddress, ushort destinationPort, byte[] payload)
{
var bindAddress = IPAddress.Any;
// Make sure parameters are consistent
//if ((sourceAddress.AddressFamily != destinationAddress.AddressFamily) || (sourceAddress.AddressFamily != bindAddress.AddressFamily))
//{
// throw new Exception("Source and destination address families don't match!");
//}
// Start building the headers
byte[] builtPacket;
UdpHeader udpPacket = new UdpHeader();
ArrayList headerList = new ArrayList();
//Socket rawSocket = null;
//SocketOptionLevel socketLevel = SocketOptionLevel.IP;
// Fill out the UDP header first
Console.WriteLine("Filling out the UDP header...");
udpPacket.SourcePort = sourcePort;
udpPacket.DestinationPort = destinationPort;
udpPacket.Length = (ushort)(UdpHeader.UdpHeaderLength + payload.Length);
udpPacket.Checksum = 0;
if (sourceAddress.AddressFamily == AddressFamily.InterNetwork)
{
Ipv4Header ipv4Packet = new Ipv4Header();
// Build the IPv4 header
Console.WriteLine("Building the IPv4 header...");
ipv4Packet.Version = 4;
ipv4Packet.Protocol = (byte)ProtocolType.Udp;
ipv4Packet.Ttl = 2;
ipv4Packet.Offset = 0;
ipv4Packet.Length = (byte)Ipv4Header.Ipv4HeaderLength;
ipv4Packet.TotalLength = (ushort)System.Convert.ToUInt16(Ipv4Header.Ipv4HeaderLength + UdpHeader.UdpHeaderLength + payload.Length);
ipv4Packet.SourceAddress = sourceAddress;
ipv4Packet.DestinationAddress = destinationAddress;
// Set the IPv4 header in the UDP header since it is required to calculate the
// pseudo header checksum
Console.WriteLine("Setting the IPv4 header for pseudo header checksum...");
udpPacket.ipv4PacketHeader = ipv4Packet;
// Add IPv4 header to list of headers -- headers should be added in th order
// they appear in the packet (i.e. IP first then UDP)
Console.WriteLine("Adding the IPv4 header to the list of header, encapsulating packet...");
headerList.Add(ipv4Packet);
//socketLevel = SocketOptionLevel.IP;
}
else if (sourceAddress.AddressFamily == AddressFamily.InterNetworkV6)
{
Ipv6Header ipv6Packet = new Ipv6Header();
// Build the IPv6 header
Console.WriteLine("Building the IPv6 header...");
ipv6Packet.Version = 6;
ipv6Packet.TrafficClass = 1;
ipv6Packet.Flow = 2;
ipv6Packet.HopLimit = 2;
ipv6Packet.NextHeader = (byte)ProtocolType.Udp;
ipv6Packet.PayloadLength = (ushort)(UdpHeader.UdpHeaderLength + payload.Length);
ipv6Packet.SourceAddress = sourceAddress;
ipv6Packet.DestinationAddress = destinationAddress;
// Set the IPv6 header in the UDP header since it is required to calculate the
// pseudo header checksum
Console.WriteLine("Setting the IPv6 header for pseudo header checksum...");
udpPacket.ipv6PacketHeader = ipv6Packet;
// Add the IPv6 header to the list of headers - headers should be added in the order
// they appear in the packet (i.e. IP first then UDP)
Console.WriteLine("Adding the IPv6 header to the list of header, encapsulating packet...");
headerList.Add(ipv6Packet);
//socketLevel = SocketOptionLevel.IPv6;
}
// Add the UDP header to list of headers after the IP header has been added
Console.WriteLine("Adding the UDP header to the list of header, after IP header...");
headerList.Add(udpPacket);
// Convert the header classes into the binary on-the-wire representation
Console.WriteLine("Converting the header classes into the binary...");
builtPacket = udpPacket.BuildPacket(headerList, payload);
/*
// Create the raw socket for this packet
Console.WriteLine("Creating the raw socket using Socket()...");
rawSocket = new Socket(sourceAddress.AddressFamily, SocketType.Raw, ProtocolType.Udp);
// Bind the socket to the interface specified
Console.WriteLine("Binding the socket to the specified interface using Bind()...");
rawSocket.Bind(new IPEndPoint(bindAddress, 0));
// Set the HeaderIncluded option since we include the IP header
Console.WriteLine("Setting the HeaderIncluded option for IP header...");
rawSocket.SetSocketOption(socketLevel, SocketOptionName.HeaderIncluded, 1);
try
{
// Send the packet!
Console.WriteLine("Sending the packet...");
int rc = rawSocket.SendTo(builtPacket, new IPEndPoint(destinationAddress, destinationPort));
Console.WriteLine("send {0} bytes to {1}", rc, destinationAddress.ToString());
}
catch (SocketException err)
{
Console.WriteLine("Socket error occurred: {0}", err.Message);
// http://msdn.microsoft.com/en-us/library/ms740668.aspx
}
finally
{
// Close the socket
Console.WriteLine("Closing the socket...");
rawSocket.Close();
}
*/
return builtPacket;
}
}
所以你只需要IP层数据包，而不是以太网包装器？@Sam Skuce它需要IP和UDP报头，不确定IP报头是否是“以太网包装器”，谢谢。如果你手动制作数据包，你还必须考虑endianness。你好，Justin。这对你有用吗？我尝试了这段代码，但当我在sender框上执行wireshark捕获时，我看到所有字段的值都完全不同，例如源端口和目标端口以及udp长度等。。。
public static class UDPPacket
{
public static byte[] Construct(IPAddress sourceAddress, ushort sourcePort, IPAddress destinationAddress, ushort destinationPort, byte[] payload)
{
var bindAddress = IPAddress.Any;
// Make sure parameters are consistent
//if ((sourceAddress.AddressFamily != destinationAddress.AddressFamily) || (sourceAddress.AddressFamily != bindAddress.AddressFamily))
//{
// throw new Exception("Source and destination address families don't match!");
//}
// Start building the headers
byte[] builtPacket;
UdpHeader udpPacket = new UdpHeader();
ArrayList headerList = new ArrayList();
//Socket rawSocket = null;
//SocketOptionLevel socketLevel = SocketOptionLevel.IP;
// Fill out the UDP header first
Console.WriteLine("Filling out the UDP header...");
udpPacket.SourcePort = sourcePort;
udpPacket.DestinationPort = destinationPort;
udpPacket.Length = (ushort)(UdpHeader.UdpHeaderLength + payload.Length);
udpPacket.Checksum = 0;
if (sourceAddress.AddressFamily == AddressFamily.InterNetwork)
{
Ipv4Header ipv4Packet = new Ipv4Header();
// Build the IPv4 header
Console.WriteLine("Building the IPv4 header...");
ipv4Packet.Version = 4;
ipv4Packet.Protocol = (byte)ProtocolType.Udp;
ipv4Packet.Ttl = 2;
ipv4Packet.Offset = 0;
ipv4Packet.Length = (byte)Ipv4Header.Ipv4HeaderLength;
ipv4Packet.TotalLength = (ushort)System.Convert.ToUInt16(Ipv4Header.Ipv4HeaderLength + UdpHeader.UdpHeaderLength + payload.Length);
ipv4Packet.SourceAddress = sourceAddress;
ipv4Packet.DestinationAddress = destinationAddress;
// Set the IPv4 header in the UDP header since it is required to calculate the
// pseudo header checksum
Console.WriteLine("Setting the IPv4 header for pseudo header checksum...");
udpPacket.ipv4PacketHeader = ipv4Packet;
// Add IPv4 header to list of headers -- headers should be added in th order
// they appear in the packet (i.e. IP first then UDP)
Console.WriteLine("Adding the IPv4 header to the list of header, encapsulating packet...");
headerList.Add(ipv4Packet);
//socketLevel = SocketOptionLevel.IP;
}
else if (sourceAddress.AddressFamily == AddressFamily.InterNetworkV6)
{
Ipv6Header ipv6Packet = new Ipv6Header();
// Build the IPv6 header
Console.WriteLine("Building the IPv6 header...");
ipv6Packet.Version = 6;
ipv6Packet.TrafficClass = 1;
ipv6Packet.Flow = 2;
ipv6Packet.HopLimit = 2;
ipv6Packet.NextHeader = (byte)ProtocolType.Udp;
ipv6Packet.PayloadLength = (ushort)(UdpHeader.UdpHeaderLength + payload.Length);
ipv6Packet.SourceAddress = sourceAddress;
ipv6Packet.DestinationAddress = destinationAddress;
// Set the IPv6 header in the UDP header since it is required to calculate the
// pseudo header checksum
Console.WriteLine("Setting the IPv6 header for pseudo header checksum...");
udpPacket.ipv6PacketHeader = ipv6Packet;
// Add the IPv6 header to the list of headers - headers should be added in the order
// they appear in the packet (i.e. IP first then UDP)
Console.WriteLine("Adding the IPv6 header to the list of header, encapsulating packet...");
headerList.Add(ipv6Packet);
//socketLevel = SocketOptionLevel.IPv6;
}
// Add the UDP header to list of headers after the IP header has been added
Console.WriteLine("Adding the UDP header to the list of header, after IP header...");
headerList.Add(udpPacket);
// Convert the header classes into the binary on-the-wire representation
Console.WriteLine("Converting the header classes into the binary...");
builtPacket = udpPacket.BuildPacket(headerList, payload);
/*
// Create the raw socket for this packet
Console.WriteLine("Creating the raw socket using Socket()...");
rawSocket = new Socket(sourceAddress.AddressFamily, SocketType.Raw, ProtocolType.Udp);
// Bind the socket to the interface specified
Console.WriteLine("Binding the socket to the specified interface using Bind()...");
rawSocket.Bind(new IPEndPoint(bindAddress, 0));
// Set the HeaderIncluded option since we include the IP header
Console.WriteLine("Setting the HeaderIncluded option for IP header...");
rawSocket.SetSocketOption(socketLevel, SocketOptionName.HeaderIncluded, 1);
try
{
// Send the packet!
Console.WriteLine("Sending the packet...");
int rc = rawSocket.SendTo(builtPacket, new IPEndPoint(destinationAddress, destinationPort));
Console.WriteLine("send {0} bytes to {1}", rc, destinationAddress.ToString());
}
catch (SocketException err)
{
Console.WriteLine("Socket error occurred: {0}", err.Message);
// http://msdn.microsoft.com/en-us/library/ms740668.aspx
}
finally
{
// Close the socket
Console.WriteLine("Closing the socket...");
rawSocket.Close();
}
*/
return builtPacket;
}
}