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302 lines
11 KiB
C#
302 lines
11 KiB
C#
using linker.libs.extends;
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using System;
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using System.Buffers;
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using System.Buffers.Binary;
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using System.Net;
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using System.Text;
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namespace linker.libs.socks5
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{
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/// <summary>
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/// socks5 数据包解析和组装
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/// </summary>
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public sealed class Socks5Parser
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{
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/// <summary>
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/// 获取客户端过来的支持的认证方式列表
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/// </summary>
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/// <param name="span"></param>
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/// <returns></returns>
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public static Socks5EnumAuthType[] GetAuthMethods(ReadOnlySpan<byte> span)
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{
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//VER NMETHODS METHODS
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// 1 1 1-255
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//版本 支持哪些认证 一个认证方式一个字节
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byte length = span[1];
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Socks5EnumAuthType[] res = new Socks5EnumAuthType[length];
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for (byte i = 0; i < length; i++)
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{
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res[i] = (Socks5EnumAuthType)span[2 + i];
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}
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return res;
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}
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/// <summary>
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/// 获取账号密码
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/// </summary>
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/// <param name="span"></param>
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/// <returns></returns>
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public static (string username, string password) GetPasswordAuthInfo(Span<byte> span)
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{
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/*
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子版本 username长度 username password长度 password
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0x01
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*/
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string username = span.Slice(2, span[1]).GetString();
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string password = span.Slice(2 + span[1] + 1, span[2 + span[1]]).GetString();
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return (username, password);
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}
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/// <summary>
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/// 获取地址
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/// </summary>
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/// <param name="data"></param>
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/// <returns></returns>
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public static ReadOnlyMemory<byte> GetRemoteEndPoint(ReadOnlyMemory<byte> data, out Socks5EnumAddressType addressType, out ushort port, out int index)
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{
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//VERSION COMMAND RSV ATYPE DST.ADDR DST.PORT
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//去掉 VERSION COMMAND RSV
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ReadOnlyMemory<byte> memory = data.Slice(3);
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ReadOnlySpan<byte> span = memory.Span;
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addressType = (Socks5EnumAddressType)span[0];
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index = 0;
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ReadOnlyMemory<byte> result = Helper.EmptyArray;
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switch (addressType)
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{
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case Socks5EnumAddressType.IPV4:
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{
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result = memory.Slice(1, 4);
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index = 1 + 4;
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}
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break;
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case Socks5EnumAddressType.Domain:
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{
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result = memory.Slice(2, span[1]);
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index = 2 + span[1];
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}
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break;
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case Socks5EnumAddressType.IPV6:
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{
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result = memory.Slice(1, 16);
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index = 1 + 16;
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}
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break;
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default:
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break;
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}
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port = BinaryPrimitives.ReadUInt16BigEndian(span.Slice(index, 2));
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index += 2;
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index += 3;
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return result;
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}
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/// <summary>
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/// 获取udp中继中的数据
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/// </summary>
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/// <param name="span"></param>
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/// <returns></returns>
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/// <exception cref="NotImplementedException"></exception>
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public static ReadOnlyMemory<byte> GetUdpData(ReadOnlyMemory<byte> span)
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{
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//RSV FRAG ATYPE DST.ADDR DST.PORT DATA
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//去掉 RSV FRAG RSV占俩字节
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span = span.Slice(3);
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return (Socks5EnumAddressType)span.Span[0] switch
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{
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Socks5EnumAddressType.IPV4 => span[(1 + 4 + 2)..],
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Socks5EnumAddressType.IPV6 => span[(1 + 16 + 2)..],
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Socks5EnumAddressType.Domain => span[(2 + span.Span[1] + 2)..],
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_ => Helper.EmptyArray,
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};
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}
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/// <summary>
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/// 生成connect返回包
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/// </summary>
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/// <param name="remoteEndPoint"></param>
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/// <param name="responseCommand"></param>
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/// <returns></returns>
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public static unsafe byte[] MakeConnectResponse(IPEndPoint remoteEndPoint, byte responseCommand)
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{
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//VER REP RSV ATYPE BND.ADDR BND.PORT
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byte[] res = new byte[6 + (remoteEndPoint.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork ? 4 : 16)];
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var span = res.AsSpan();
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res[0] = 5;
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res[1] = responseCommand;
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res[2] = 0;
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res[3] = (byte)(remoteEndPoint.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork ? Socks5EnumAddressType.IPV4 : Socks5EnumAddressType.IPV6);
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remoteEndPoint.Address.TryWriteBytes(span.Slice(4), out _);
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int port = remoteEndPoint.Port;
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ref int _port = ref port;
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fixed (void* p = &_port)
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{
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byte* pp = (byte*)p;
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res[^2] = *(pp + 1);
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res[^1] = *pp;
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}
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return res;
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}
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/// <summary>
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/// 生成udp中中继数据包
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/// </summary>
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/// <param name="remoteEndPoint"></param>
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/// <param name="data"></param>
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/// <returns></returns>
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public static unsafe byte[] MakeUdpResponse(IPEndPoint remoteEndPoint, ReadOnlyMemory<byte> data, out int length)
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{
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//RSV FRAG ATYPE DST.ADDR DST.PORT DATA
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//RSV占俩字节
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int ipLength = (remoteEndPoint.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork ? 4 : 16);
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length = 4 + ipLength + 2 + data.Length;
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byte[] res = ArrayPool<byte>.Shared.Rent(length);
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var span = res.AsSpan();
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res[0] = 0;
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res[1] = 0;
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res[2] = 0; //FRAG
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res[3] = (byte)(ipLength == 4 ? Socks5EnumAddressType.IPV4 : Socks5EnumAddressType.IPV6);
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int index = 4;
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remoteEndPoint.Address.TryWriteBytes(span.Slice(index), out _);
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index += ipLength;
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int port = remoteEndPoint.Port;
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ref int _port = ref port;
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fixed (void* p = &_port)
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{
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byte* pp = (byte*)p;
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res[index] = *(pp + 1);
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res[index + 1] = *pp;
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}
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index += 2;
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data.CopyTo(res.AsMemory(index, data.Length));
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return res;
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}
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public static void Return(byte[] data)
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{
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ArrayPool<byte>.Shared.Return(data);
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}
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public static EnumProxyValidateDataResult ValidateData(Socks5EnumStep step, Memory<byte> data)
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{
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return step switch
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{
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Socks5EnumStep.Request => ValidateRequestData(data),
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Socks5EnumStep.Command => ValidateCommandData(data),
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Socks5EnumStep.Auth => ValidateAuthData(data, Socks5EnumAuthType.Password),
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Socks5EnumStep.Forward => EnumProxyValidateDataResult.Equal,
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Socks5EnumStep.ForwardUdp => EnumProxyValidateDataResult.Equal,
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_ => EnumProxyValidateDataResult.Equal
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};
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}
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/// <summary>
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/// 验证 request数据完整性
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/// </summary>
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/// <param name="data"></param>
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/// <returns></returns>
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public static EnumProxyValidateDataResult ValidateRequestData(ReadOnlyMemory<byte> data)
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{
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/*
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* VERSION METHODS_COUNT METHODS
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* 1字节 1字节 1到255字节，长度由METHODS_COUNT值决定
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* 0x05 0x03 0x00 0x01 0x02
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*/
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if (data.Length < 2 || data.Length < 2 + data.Span[1])
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{
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return EnumProxyValidateDataResult.TooShort;
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}
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return EnumProxyValidateDataResult.Equal;
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}
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/// <summary>
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/// 验证command数据完整性
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/// </summary>
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/// <param name="data"></param>
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/// <returns></returns>
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public static EnumProxyValidateDataResult ValidateCommandData(ReadOnlyMemory<byte> data)
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{
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/*
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* VERSION COMMAND RSV ADDRESS_TYPE DST.ADDR DST.PORT
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* 1 1 1 1 1-255 2
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* 域名模式下 DST.ADDR第一个字节是域名长度，那么整个数据至少8个字节
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*/
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if (data.Length < 8) return EnumProxyValidateDataResult.TooShort;
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var span = data.Span;
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int addrLength = (Socks5EnumAddressType)span[3] switch
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{
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Socks5EnumAddressType.IPV4 => 4 + 2,
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Socks5EnumAddressType.Domain => span[4] + 1 + 2, //DST.ADDR第一个字节是域名长度 剩下的才是域名数据
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Socks5EnumAddressType.IPV6 => 16 + 2,
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_ => throw new NotImplementedException(),
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};
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if (data.Length < 4 + addrLength)
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{
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return EnumProxyValidateDataResult.TooShort;
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}
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return EnumProxyValidateDataResult.Equal;
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}
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/// <summary>
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/// 验证认证数据完整性
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/// </summary>
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/// <param name="data"></param>
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/// <param name="authType"></param>
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/// <returns></returns>
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public static EnumProxyValidateDataResult ValidateAuthData(ReadOnlyMemory<byte> data, Socks5EnumAuthType authType)
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{
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return authType switch
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{
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Socks5EnumAuthType.NoAuth => EnumProxyValidateDataResult.Equal,
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Socks5EnumAuthType.Password => ValidateAuthPasswordData(data),
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Socks5EnumAuthType.GSSAPI => EnumProxyValidateDataResult.Equal,
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Socks5EnumAuthType.IANA => EnumProxyValidateDataResult.Equal,
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Socks5EnumAuthType.UnKnow => EnumProxyValidateDataResult.Bad,
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Socks5EnumAuthType.NotSupported => EnumProxyValidateDataResult.Bad,
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_ => EnumProxyValidateDataResult.Bad,
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};
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}
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private static EnumProxyValidateDataResult ValidateAuthPasswordData(ReadOnlyMemory<byte> data)
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{
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/*
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VERSION USERNAME_LENGTH USERNAME PASSWORD_LENGTH PASSWORD
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1字节 1字节 1到255字节 1字节 1到255字节
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0x01 0x01 0x0a 0x01 0x0a
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*/
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var span = data.Slice(1).Span;
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//至少有 USERNAME_LENGTH PASSWORD_LENGTH 字节以上
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if (span.Length <= 2)
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{
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return EnumProxyValidateDataResult.TooShort;
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}
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byte nameLength = span[0];
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//至少有 USERNAME_LENGTH USERNAME PASSWORD_LENGTH
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if (span.Length < nameLength + 1 + 1)
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{
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return EnumProxyValidateDataResult.TooShort;
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}
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byte passwordLength = span[1 + nameLength];
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if (span.Length < 1 + 1 + nameLength + passwordLength)
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{
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return EnumProxyValidateDataResult.TooShort;
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}
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return EnumProxyValidateDataResult.Equal;
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}
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}
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}
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