我需要计算 ICMPv6 校验和。我在 RFC 2460 中找到了正确的手册，并用 c# 编写了代码，粘贴在下面。在代码中，您可以看到我添加到校验和源 IP、数据包的目标 IP，而不是 ICMPv6 消息长度（邻居广告为 32 个字节），然后我添加下一个标头 ID，即 ICMPv6 的 58。然后是 FOR 循环，它将整个 ICMPv6 消息添加到校验和（我相信它以消息类型开头，例如 88 00 ... 用于邻居广告）。比我计算和补充校验和，但它是错误的。我正在尝试为真实嗅探的邻居广告计算此校验和，该校验和也在下方，但我无法获得相同的校验和。我的代码可能有什么问题？
static void Main(string[] args)
{
ICaptureDevice device = new OfflineCaptureDevice("icmp.pcap");
device.Open();
device.OnPacketArrival += new SharpPcap.PacketArrivalEventHandler(device_OnPacketArrival);
device.Capture();
Console.ReadKey();
}
private static void device_OnPacketArrival(object sender, SharpPcap.CaptureEventArgs e)
{
try
{
//packet conversions
var packet = PacketDotNet.Packet.ParsePacket(e.Packet);
var ethernetPacket = ((PacketDotNet.EthernetPacket)packet);
int dlzka_packetu = e.Packet.Data.Length;
string eth = BitConverter.ToString(ethernetPacket.Bytes);
//now its in string field format - one string item is one byte, e.g. FF
string[] eth_final2 = eth.Split('-');
foreach (string bytes in eth_final2) { Console.Write(bytes + " "); }
Console.WriteLine();
//taking out source IP
IPAddress src_ip = IPAddress.Parse(eth_final2[22]+eth_final2[23]+":"+eth_final2[24]+eth_final2[25]+":"+eth_final2[26]+eth_final2[27]+":"+eth_final2[28]+eth_final2[29]+":"+eth_final2[30]+eth_final2[31]+":"+eth_final2[32]+eth_final2[33]+":"+eth_final2[34]+eth_final2[35]+":"+eth_final2[36]+eth_final2[37]);
//destination IP
IPAddress dst_ip = IPAddress.Parse(eth_final2[38] + eth_final2[39] + ":" + eth_final2[40] + eth_final2[41] + ":" + eth_final2[42] + eth_final2[43] + ":" + eth_final2[44] + eth_final2[45] + ":" + eth_final2[46] + eth_final2[47] + ":" + eth_final2[48] + eth_final2[49] + ":" + eth_final2[50] + eth_final2[51] + ":" + eth_final2[52] + eth_final2[53]);
Console.WriteLine(src_ip);
Console.WriteLine(dst_ip);
int icmpv6_length = 32;
int next_header = 58;
Console.WriteLine();
string icmp_payload = "";
//taking out ICMPv6 message
for (int i = 54; i < 54 + 32; i++)
{
if (i == 56 || i == 57) { icmp_payload += "00"; }
else icmp_payload += eth_final2[i];
}
Console.WriteLine(icmp_payload);
byte[] icmp_bytes = GetStringToBytes(icmp_payload);
//CALLING THE FUNCTION ICMPchecksum
ushort sum = ICMPchecksum(src_ip.GetAddressBytes(), dst_ip.GetAddressBytes(), BitConverter.GetBytes(icmpv6_length), BitConverter.GetBytes(next_header), icmp_bytes);
Console.WriteLine(sum.ToString("X"));
}
catch (Exception ex)
{
Console.WriteLine("ERROR");
}
}
static byte[] GetStringToBytes(string value)
{
SoapHexBinary shb = SoapHexBinary.Parse(value);
return shb.Value;
}
static ushort ICMPchecksum(byte[] src_ip, byte[] dst_ip, byte[] length, byte[] next, byte[] payload)
{
ushort checksum = 0;
//length of byte fields
Console.WriteLine("src_ip: "+src_ip.Length+" dst_ip: "+dst_ip.Length+" length: "+length.Length+" next_header: "+next.Length+" payload: "+payload.Length);
//display all fields, which will be used for checksum calculation
Console.WriteLine(BitConverter.ToString(src_ip));
Console.WriteLine(BitConverter.ToString(dst_ip));
Console.WriteLine(BitConverter.ToString(length));
Console.WriteLine(BitConverter.ToString(next));
Console.WriteLine(BitConverter.ToString(payload));
//ADDS SOURCE IPv6 address
checksum += BitConverter.ToUInt16(src_ip, 0);
checksum += BitConverter.ToUInt16(src_ip, 2);
checksum += BitConverter.ToUInt16(src_ip, 4);
checksum += BitConverter.ToUInt16(src_ip, 6);
checksum += BitConverter.ToUInt16(src_ip, 8);
checksum += BitConverter.ToUInt16(src_ip, 10);
checksum += BitConverter.ToUInt16(src_ip, 12);
checksum += BitConverter.ToUInt16(src_ip, 14);
//ADDS DEST IPv6 address
checksum += BitConverter.ToUInt16(dst_ip, 0);
checksum += BitConverter.ToUInt16(dst_ip, 2);
checksum += BitConverter.ToUInt16(dst_ip, 4);
checksum += BitConverter.ToUInt16(dst_ip, 6);
checksum += BitConverter.ToUInt16(dst_ip, 8);
checksum += BitConverter.ToUInt16(dst_ip, 10);
checksum += BitConverter.ToUInt16(dst_ip, 12);
checksum += BitConverter.ToUInt16(dst_ip, 14);
//ADDS LENGTH OF ICMPv6 packet
checksum += BitConverter.ToUInt16(length, 0);
checksum += BitConverter.ToUInt16(length, 2);
//ADDS NEXT HEADER ID = 58
checksum += BitConverter.ToUInt16(next, 0);
checksum += BitConverter.ToUInt16(next, 2);
//ADDS WHOLE ICMPv6 message
for (int i = 0; i < payload.Length; i = i + 2)
{
Console.WriteLine(i);
checksum += BitConverter.ToUInt16(payload, i);
}
checksum += (ushort)(checksum >> 16);
return (ushort)~checksum;
}
这是数据包屏幕。
唯一链接：http: //img831.imageshack.us/img831/7237/icmpv6.png
加上链接，您可以在其中下载文件，我正在使用该链接进行测试：
http://www.2shared.com/file/wIETWTWB/icmp.html
感谢帮助。