C# IP碎片导致校验和错误消息

我正在使用

PcapDorNet

dll，我试图将我的流量分割成碎片：

private IEnumerable<Packet> SplitPacket(Packet packet, int numberOfFragments)
        {
            IpV4Datagram ipV4Datagram = packet.Ethernet.IpV4;
            Datagram datagram = packet.Ethernet.IpV4.Payload;
            TransportLayer transportlayer = GetTransportLayer(packet);
            if (transportlayer != null)
            {
                EthernetLayer ethernet = (EthernetLayer)packet.Ethernet.ExtractLayer();
                ILayer layer = packet.Ethernet.IpV4.ExtractLayer();
                IpV4Layer ipV4Layer = (IpV4Layer)packet.Ethernet.IpV4.ExtractLayer();
                ipV4Layer.HeaderChecksum = null;
                DateTime packetTimestamp = packet.Timestamp;                
                PayloadLayer payload = (PayloadLayer)packet.Ethernet.IpV4.Payload.ExtractLayer(); //extract the data

                int totalLength = payload.Length;
                int partialLength = totalLength / numberOfFragments; //split data into smaller segments
                partialLength = (partialLength / 8) * 8; //make sure it's divisible with 8
                if (partialLength == 0)
                    partialLength = 8;
                //(http://en.wikipedia.org/wiki/IPv4#Fragmentation_and_reassembly)
                ushort offset = 0; //send one by one

                while (offset < totalLength)
                {
                    int fragmentLength = partialLength; //get length for this fragment
                    IpV4FragmentationOptions options = IpV4FragmentationOptions.MoreFragments;

                    if (offset + fragmentLength >= totalLength) //is this the last fragment ? trim length if needed
                    {
                        options = IpV4FragmentationOptions.None;
                        fragmentLength = totalLength - offset;
                    }

                    byte[] newBuffer = ipV4Datagram.Payload.ToArray(); //copy the actual data into a new buffer
                    PayloadLayer newPayload = new PayloadLayer { Data = new Datagram(newBuffer, offset, fragmentLength) };
                    ipV4Layer.Fragmentation = new IpV4Fragmentation(options, offset); //change IP layer fragmentation options
                    transportlayer.Checksum = null;
                    yield return PacketBuilder.Build(packetTimestamp, ethernet, ipV4Layer, transportlayer, newPayload);
                    offset += (ushort)fragmentLength; //next offset
                }
            }
        }

private IEnumerable SplitPacket（数据包包，int numberOfFragments）
{
IpV4数据报IpV4数据报=packet.Ethernet.IpV4；
数据报数据报=packet.Ethernet.IpV4.Payload；
TransportLayer TransportLayer=GetTransportLayer（数据包）；
如果（transportlayer！=null）
{
EthernetLayer ethernet=（EthernetLayer）packet.ethernet.ExtractLayer（）；
ILayer layer=packet.Ethernet.IpV4.ExtractLayer（）；
IpV4Layer IpV4Layer=（IpV4Layer）packet.Ethernet.IpV4.ExtractLayer（）；
ipV4Layer.HeaderChecksum=null；
DateTime packetTimestamp=packet.Timestamp；
PayloadLayer有效负载=（PayloadLayer）packet.Ethernet.IpV4.payload.ExtractLayer（）；//提取数据
int totalLength=有效载荷长度；
int partialLength=totalLength/numberOfFragments；//将数据分割成更小的段
partialLength=（partialLength/8）*8；//确保它可以被8整除
if（partialLength==0）
部分长度=8；
//(http://en.wikipedia.org/wiki/IPv4#Fragmentation_and_reassembly)
ushort offset=0；//逐个发送
而（偏移量<总长度）
{
int fragmentLength=partialLength；//获取此片段的长度
IpV4FragmentationOptions=IpV4FragmentationOptions.MoreFragments；
if（offset+fragmentLength>=totalLength）//这是最后一个片段吗？如果需要，修剪长度
{
选项=IPV4碎片选项。无；
碎片长度=总长度-偏移量；
}
byte[]newBuffer=ipV4Datagram.Payload.ToArray（）；//将实际数据复制到新的缓冲区中
PayloadLayer newPayload=new PayloadLayer{Data=new Datagram（newBuffer，offset，fragmentLength）}；
ipV4Layer.Fragmentation=新IpV4Fragmentation（选项，偏移量）；//更改IP层碎片选项
transportlayer.Checksum=null；
返回PacketBuilder.Build（packetTimestamp、以太网、ipV4Layer、transportlayer、newPayload）；
偏移量+=（ushort）碎片长度；//下一个偏移量
}
}
}

我的输入数据包是

TCP数据包

，输出是4个数据包：3个

IPv4数据包

，最后一个是

TCP

，但我收到的数据包显示在TCP层字段下此消息：

校验和：0x5d17[不正确，应为0xabb7（可能由“TCP”引起 校验和卸载“）]

使用UDP时，似乎每个UDP数据包都被分成几个IPv4数据包，最后一个数据包是UDP，但在UDP情况下看起来很好。 我做错什么了吗

---

请查看原始数据包和碎片：

中似乎有一个非常类似的问题，并对代码进行了更正

我相信遵循那里的建议将有助于解决您的问题