test: Decrypt multi segment AEAD data

Socks5/Utils/Socks5TestUtils.cs

@@ -21,7 +21,7 @@ public static class Socks5TestUtils
 		/// <summary>
 		/// 使用 HTTP1.1 204 测试 SOCKS5 CONNECT 
 		/// <para>Example:</para>
-		/// <para>https://www.google.com/generate_204</para>
+		/// <para>http://www.google.com/generate_204</para>
 		/// <para>http://connectivitycheck.gstatic.com/generate_204</para>
 		/// <para>http://connect.rom.miui.com/generate_204</para>
 		/// <para>http://cp.cloudflare.com</para>

UnitTest/AEADShadowsocksCryptoTest.cs

@@ -29,25 +29,24 @@ private static void TestAEAD(string method, string password, string str, string
 		private static void TestTcpDecrypt(string method, string password, string str, string encHex)
 		{
 			Span<byte> origin = Encoding.UTF8.GetBytes(str);
-			var enc = new ReadOnlySequence<byte>(encHex.FromHex());
+			var encBuffer = encHex.FromHex();
 
-			Span<byte> buffer = new byte[enc.Length];
+			Span<byte> buffer = new byte[encBuffer.Length];
 
 			using var crypto = (AEADShadowsocksCrypto)ShadowsocksCrypto.Create(method, password);
 
-			var e0 = enc.Slice(0, crypto.SaltLength);
+			var secondIndex = RandomNumberGenerator.GetInt32(crypto.SaltLength, encBuffer.Length);
+			var multiSequence = TestUtils.GetMultiSegmentSequence(encBuffer, crypto.SaltLength, secondIndex);
+			Assert.IsFalse(multiSequence.IsSingleSegment);
+			Assert.AreEqual(encBuffer.LongLength, multiSequence.Length);
+
+			var e0 = multiSequence.Slice(0, crypto.SaltLength);
 			var o2 = crypto.DecryptTCP(ref e0, buffer);
 			Assert.AreEqual(crypto.SaltLength, e0.Length);
 			Assert.AreEqual(0, o2);
 
-			var e1Length = crypto.SaltLength + AEADShadowsocksCrypto.ChunkOverheadSize + 1;
-			var e1 = enc.Slice(0, e1Length);
-			var o0 = crypto.DecryptTCP(ref e1, buffer);
-			Assert.AreEqual(e1Length - crypto.SaltLength, e1.Length);
-			Assert.AreEqual(0, o0);
-
-			var remain = enc.Slice(crypto.SaltLength);
-			var o1 = crypto.DecryptTCP(ref remain, buffer[o0..]);
+			var remain = multiSequence;
+			var o1 = crypto.DecryptTCP(ref remain, buffer);
 			Assert.AreEqual(0, remain.Length);
 			Assert.AreEqual(origin.Length, o1);
 

UnitTest/BufferSegment.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Buffers;
+
+namespace UnitTest
+{
+	internal class BufferSegment : ReadOnlySequenceSegment<byte>
+	{
+		public BufferSegment(Memory<byte> memory)
+		{
+			Memory = memory;
+		}
+
+		public BufferSegment Append(Memory<byte> memory)
+		{
+			var segment = new BufferSegment(memory)
+			{
+				RunningIndex = RunningIndex + Memory.Length
+			};
+			Next = segment;
+			return segment;
+		}
+	}
+}

UnitTest/TestUtils.cs

@@ -0,0 +1,33 @@
+using Microsoft;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Buffers;
+using System.Linq;
+
+namespace UnitTest
+{
+	internal static class TestUtils
+	{
+		public static ReadOnlySequence<byte> GetMultiSegmentSequence(Memory<byte> source, params int[] index)
+		{
+			Requires.Argument(index.LongLength > 1, nameof(index), @"index length must >1");
+			var orderedIndex = index.OrderBy(x => x);
+			var first = new BufferSegment(source[..orderedIndex.First()]);
+
+			var last = first;
+			var length = index[0];
+
+			foreach (var i in index.Skip(1))
+			{
+				last = last.Append(source.Slice(length, i - length));
+				length = i;
+			}
+
+			last = last.Append(source[length..]);
+
+			var sequence = new ReadOnlySequence<byte>(first, 0, last, last.Memory.Length);
+			Assert.AreEqual(source.Length, sequence.Length);
+			return sequence;
+		}
+	}
+}