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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Buffers;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Server.Kestrel.FunctionalTests;
using Microsoft.AspNetCore.InternalTesting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Xunit;
#if SOCKETS
namespace Microsoft.AspNetCore.Server.Kestrel.Sockets.FunctionalTests;
#else
namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests;
#endif
public class MaxRequestBufferSizeTests : LoggedTest
{
// The client is typically paused after uploading this many bytes:
//
// OS MaxRequestBufferSize (MB) connectionAdapter Transport min pause (MB) max pause (MB)
// --------------- ------------------------- ----------------- --------- -------------- --------------
// Windows 10 1803 1 false Libuv 1.7 3.3
// Windows 10 1803 1 false Sockets 1.7 4.4
// Windows 10 1803 1 true Libuv 3.0 8.4
// Windows 10 1803 1 true Sockets 3.2 9.0
//
// Windows 10 1803 5 false Libuv 6 13
// Windows 10 1803 5 false Sockets 7 24
// Windows 10 1803 5 true Libuv 12 12
// Windows 10 1803 5 true Sockets 12 36
// Ubuntu 18.04 5 false Libuv 13 15
// Ubuntu 18.04 5 false Sockets 13 15
// Ubuntu 18.04 5 true Libuv 19 20
// Ubuntu 18.04 5 true Sockets 18 20
// macOS 10.13.4 5 false Libuv 6 6
// macOS 10.13.4 5 false Sockets 6 6
// macOS 10.13.4 5 true Libuv 11 11
// macOS 10.13.4 5 true Sockets 11 11
//
// When connectionAdapter=true, the MaxRequestBufferSize is set on two pipes, so it's effectively doubled.
//
// To ensure reliability, _dataLength must be greater than the largest "max pause" in any configuration
private const int _dataLength = 100 * 1024 * 1024;
private static readonly string[] _requestLines = new[]
{
"POST / HTTP/1.1\r\n",
"Host: \r\n",
$"Content-Length: {_dataLength}\r\n",
"\r\n"
};
public static IEnumerable<object[]> LargeUploadData
{
get
{
var totalHeaderSize = 0;
for (var i = 1; i < _requestLines.Length - 1; i++)
{
totalHeaderSize += _requestLines[i].Length;
}
var maxRequestBufferSizeValues = new Tuple<long?, bool>[] {
// Smallest buffer that can hold the test request headers without causing
// the server to hang waiting for the end of the request line or
// a header line.
Tuple.Create((long?)totalHeaderSize, true),
// Small buffer, but large enough to hold all request headers.
Tuple.Create((long?)16 * 1024, true),
// Default buffer.
Tuple.Create((long?)1024 * 1024, true),
// Larger than default, but still significantly lower than data, so client should be paused.
Tuple.Create((long?)5 * 1024 * 1024, true),
// Even though maxRequestBufferSize < _dataLength, client should not be paused since the
// OS-level buffers in client and/or server will handle the overflow.
Tuple.Create((long?)_dataLength - 1, false),
// Buffer is exactly the same size as data. Exposed race condition where
// the connection was resumed after socket was disconnected.
Tuple.Create((long?)_dataLength, false),
// Largest possible buffer, should never trigger backpressure.
Tuple.Create((long?)long.MaxValue, false),
// Disables all code related to computing and limiting the size of the input buffer.
Tuple.Create((long?)null, false)
};
var sslValues = new[] { true, false };
return from maxRequestBufferSize in maxRequestBufferSizeValues
from ssl in sslValues
select new object[]
{
maxRequestBufferSize.Item1,
ssl,
maxRequestBufferSize.Item2
};
}
}
// On helix retry list - inherently flaky (trying to manipulate the state of the server's buffer)
[Theory]
[MemberData(nameof(LargeUploadData))]
public async Task LargeUpload(long? maxRequestBufferSize, bool connectionAdapter, bool expectPause)
{
// Parameters
var data = new byte[_dataLength];
var bytesWrittenTimeout = TimeSpan.FromMilliseconds(100);
var bytesWrittenPollingInterval = TimeSpan.FromMilliseconds(bytesWrittenTimeout.TotalMilliseconds / 10);
var maxSendSize = 4096;
var startReadingRequestBody = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
var clientFinishedSendingRequestBody = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
var lastBytesWritten = DateTime.MaxValue;
var memoryPoolFactory = new DiagnosticMemoryPoolFactory(allowLateReturn: true);
using (var host = await StartHost(maxRequestBufferSize, data, connectionAdapter, startReadingRequestBody, clientFinishedSendingRequestBody, memoryPoolFactory.Create))
{
var port = host.GetPort();
using (var socket = CreateSocket(port))
using (var stream = new NetworkStream(socket))
{
await WritePostRequestHeaders(stream, data.Length);
var bytesWritten = 0;
Func<Task> sendFunc = async () =>
{
while (bytesWritten < data.Length)
{
var size = Math.Min(data.Length - bytesWritten, maxSendSize);
await stream.WriteAsync(data, bytesWritten, size).ConfigureAwait(false);
bytesWritten += size;
lastBytesWritten = DateTime.Now;
}
Assert.Equal(data.Length, bytesWritten);
clientFinishedSendingRequestBody.TrySetResult();
};
var sendTask = sendFunc();
if (expectPause)
{
// The minimum is (maxRequestBufferSize - maxSendSize + 1), since if bytesWritten is
// (maxRequestBufferSize - maxSendSize) or smaller, the client should be able to
// complete another send.
var minimumExpectedBytesWritten = maxRequestBufferSize.Value - maxSendSize + 1;
// The maximum is harder to determine, since there can be OS-level buffers in both the client
// and server, which allow the client to send more than maxRequestBufferSize before getting
// paused. We assume the combined buffers are smaller than the difference between
// data.Length and maxRequestBufferSize.
var maximumExpectedBytesWritten = data.Length - 1;
// Block until the send task has gone a while without writing bytes AND
// the bytes written exceeds the minimum expected. This indicates the server buffer
// is full.
//
// If the send task is paused before the expected number of bytes have been
// written, keep waiting since the pause may have been caused by something else
// like a slow machine.
while ((DateTime.Now - lastBytesWritten) < bytesWrittenTimeout ||
bytesWritten < minimumExpectedBytesWritten)
{
await Task.Delay(bytesWrittenPollingInterval);
}
// Verify the number of bytes written before the client was paused.
Assert.InRange(bytesWritten, minimumExpectedBytesWritten, maximumExpectedBytesWritten);
// Tell server to start reading request body
startReadingRequestBody.TrySetResult();
// Wait for sendTask to finish sending the remaining bytes
await sendTask;
}
else
{
// Ensure all bytes can be sent before the server starts reading
await sendTask;
// Tell server to start reading request body
startReadingRequestBody.TrySetResult();
}
await AssertStreamContains(stream, $"bytesRead: {data.Length}");
}
await host.StopAsync();
}
await memoryPoolFactory.WhenAllBlocksReturned(TestConstants.DefaultTimeout);
}
[Fact]
public async Task ServerShutsDownGracefullyWhenMaxRequestBufferSizeExceeded()
{
// Parameters
var data = new byte[_dataLength];
var bytesWrittenTimeout = TimeSpan.FromMilliseconds(100);
var bytesWrittenPollingInterval = TimeSpan.FromMilliseconds(bytesWrittenTimeout.TotalMilliseconds / 10);
var maxSendSize = 4096;
var startReadingRequestBody = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
var clientFinishedSendingRequestBody = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
var lastBytesWritten = DateTime.MaxValue;
var memoryPoolFactory = new DiagnosticMemoryPoolFactory(allowLateReturn: true);
using (var host = await StartHost(16 * 1024, data, false, startReadingRequestBody, clientFinishedSendingRequestBody, memoryPoolFactory.Create))
{
var port = host.GetPort();
using (var socket = CreateSocket(port))
using (var stream = new NetworkStream(socket))
{
await WritePostRequestHeaders(stream, data.Length);
var bytesWritten = 0;
Func<Task> sendFunc = async () =>
{
while (bytesWritten < data.Length)
{
var size = Math.Min(data.Length - bytesWritten, maxSendSize);
await stream.WriteAsync(data, bytesWritten, size).ConfigureAwait(false);
bytesWritten += size;
lastBytesWritten = DateTime.Now;
}
clientFinishedSendingRequestBody.TrySetResult();
};
var ignore = sendFunc();
// The minimum is (maxRequestBufferSize - maxSendSize + 1), since if bytesWritten is
// (maxRequestBufferSize - maxSendSize) or smaller, the client should be able to
// complete another send.
var minimumExpectedBytesWritten = (16 * 1024) - maxSendSize + 1;
// The maximum is harder to determine, since there can be OS-level buffers in both the client
// and server, which allow the client to send more than maxRequestBufferSize before getting
// paused. We assume the combined buffers are smaller than the difference between
// data.Length and maxRequestBufferSize.
var maximumExpectedBytesWritten = data.Length - 1;
// Block until the send task has gone a while without writing bytes AND
// the bytes written exceeds the minimum expected. This indicates the server buffer
// is full.
//
// If the send task is paused before the expected number of bytes have been
// written, keep waiting since the pause may have been caused by something else
// like a slow machine.
while ((DateTime.Now - lastBytesWritten) < bytesWrittenTimeout ||
bytesWritten < minimumExpectedBytesWritten)
{
await Task.Delay(bytesWrittenPollingInterval);
}
// Verify the number of bytes written before the client was paused.
Assert.InRange(bytesWritten, minimumExpectedBytesWritten, maximumExpectedBytesWritten);
// Dispose host prior to closing connection to verify the server doesn't throw during shutdown
// if a connection no longer has alloc and read callbacks configured.
try
{
await host.StopAsync();
}
// Remove when https://github.com/dotnet/runtime/issues/40290 is fixed
catch (OperationCanceledException)
{
}
host.Dispose();
}
}
// Allow appfunc to unblock
startReadingRequestBody.SetResult();
clientFinishedSendingRequestBody.SetResult();
await memoryPoolFactory.WhenAllBlocksReturned(TestConstants.DefaultTimeout);
}
private async Task<IHost> StartHost(long? maxRequestBufferSize,
byte[] expectedBody,
bool useConnectionAdapter,
TaskCompletionSource startReadingRequestBody,
TaskCompletionSource clientFinishedSendingRequestBody,
Func<MemoryPool<byte>> memoryPoolFactory = null)
{
var host = TransportSelector.GetHostBuilder(memoryPoolFactory, maxRequestBufferSize)
.ConfigureWebHost(webHostBuilder =>
{
webHostBuilder
.UseKestrel(options =>
{
options.Listen(new IPEndPoint(IPAddress.Loopback, 0), listenOptions =>
{
if (useConnectionAdapter)
{
listenOptions.UsePassThrough();
}
});
options.Limits.MaxRequestBufferSize = maxRequestBufferSize;
if (maxRequestBufferSize.HasValue &&
maxRequestBufferSize.Value < options.Limits.MaxRequestLineSize)
{
options.Limits.MaxRequestLineSize = (int)maxRequestBufferSize;
}
if (maxRequestBufferSize.HasValue &&
maxRequestBufferSize.Value < options.Limits.MaxRequestHeadersTotalSize)
{
options.Limits.MaxRequestHeadersTotalSize = (int)maxRequestBufferSize;
}
options.Limits.MinRequestBodyDataRate = null;
options.Limits.MaxRequestBodySize = _dataLength;
})
.UseContentRoot(Directory.GetCurrentDirectory())
.Configure(app => app.Run(async context =>
{
await startReadingRequestBody.Task.TimeoutAfter(TimeSpan.FromSeconds(120));
var buffer = new byte[expectedBody.Length];
var bytesRead = 0;
while (bytesRead < buffer.Length)
{
bytesRead += await context.Request.Body.ReadAsync(buffer, bytesRead, buffer.Length - bytesRead);
}
await clientFinishedSendingRequestBody.Task.TimeoutAfter(TimeSpan.FromSeconds(120));
// Verify client didn't send extra bytes
if (await context.Request.Body.ReadAsync(new byte[1], 0, 1) != 0)
{
context.Response.StatusCode = StatusCodes.Status500InternalServerError;
await context.Response.WriteAsync("Client sent more bytes than expectedBody.Length");
return;
}
await context.Response.WriteAsync($"bytesRead: {bytesRead}");
}));
})
.ConfigureServices(AddTestLogging)
.Build();
await host.StartAsync();
return host;
}
private static Socket CreateSocket(int port)
{
var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Timeouts large enough to prevent false positives, but small enough to fail quickly.
socket.SendTimeout = 10 * 1000;
socket.ReceiveTimeout = 120 * 1000;
socket.Connect(IPAddress.Loopback, port);
return socket;
}
private static async Task WritePostRequestHeaders(Stream stream, int contentLength)
{
using (var writer = new StreamWriter(stream, Encoding.ASCII, bufferSize: 1024, leaveOpen: true))
{
foreach (var line in _requestLines)
{
await writer.WriteAsync(line).ConfigureAwait(false);
}
}
}
// THIS IS NOT GENERAL PURPOSE. If the initial characters could repeat, this is broken. However, since we're
// looking for /bytesWritten: \d+/ and the initial "b" cannot occur elsewhere in the pattern, this works.
private static async Task AssertStreamContains(Stream stream, string expectedSubstring)
{
var expectedBytes = Encoding.ASCII.GetBytes(expectedSubstring);
var exptectedLength = expectedBytes.Length;
var responseBuffer = new byte[exptectedLength];
var matchedChars = 0;
while (matchedChars < exptectedLength)
{
var count = await stream.ReadAsync(responseBuffer, 0, exptectedLength - matchedChars).DefaultTimeout();
if (count == 0)
{
Assert.True(false, "Stream completed without expected substring.");
}
for (var i = 0; i < count && matchedChars < exptectedLength; i++)
{
if (responseBuffer[i] == expectedBytes[matchedChars])
{
matchedChars++;
}
else
{
matchedChars = 0;
}
}
}
}
}
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