aspnetcore/src/Microsoft.AspNetCore.Server.../Internal/Infrastructure/HttpUtilities.cs

256 lines
11 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Text;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Server.Kestrel.Internal.Http;
namespace Microsoft.AspNetCore.Server.Kestrel.Internal.Infrastructure
{
public static class HttpUtilities
{
public const string Http10Version = "HTTP/1.0";
public const string Http11Version = "HTTP/1.1";
// readonly primitive statics can be Jit'd to consts https://github.com/dotnet/coreclr/issues/1079
private readonly static ulong _httpConnectMethodLong = GetAsciiStringAsLong("CONNECT ");
private readonly static ulong _httpDeleteMethodLong = GetAsciiStringAsLong("DELETE \0");
private const uint _httpGetMethodInt = 542393671; // retun of GetAsciiStringAsInt("GET "); const results in better codegen
private readonly static ulong _httpHeadMethodLong = GetAsciiStringAsLong("HEAD \0\0\0");
private readonly static ulong _httpPatchMethodLong = GetAsciiStringAsLong("PATCH \0\0");
private readonly static ulong _httpPostMethodLong = GetAsciiStringAsLong("POST \0\0\0");
private readonly static ulong _httpPutMethodLong = GetAsciiStringAsLong("PUT \0\0\0\0");
private readonly static ulong _httpOptionsMethodLong = GetAsciiStringAsLong("OPTIONS ");
private readonly static ulong _httpTraceMethodLong = GetAsciiStringAsLong("TRACE \0\0");
private const ulong _http10VersionLong = 3471766442030158920; // GetAsciiStringAsLong("HTTP/1.0"); const results in better codegen
private const ulong _http11VersionLong = 3543824036068086856; // GetAsciiStringAsLong("HTTP/1.1"); const results in better codegen
private readonly static ulong _mask8Chars = GetMaskAsLong(new byte[] { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff });
private readonly static ulong _mask7Chars = GetMaskAsLong(new byte[] { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 });
private readonly static ulong _mask6Chars = GetMaskAsLong(new byte[] { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00 });
private readonly static ulong _mask5Chars = GetMaskAsLong(new byte[] { 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00 });
private readonly static ulong _mask4Chars = GetMaskAsLong(new byte[] { 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 });
private readonly static Tuple<ulong, ulong, HttpMethod, int, bool>[] _knownMethods = new Tuple<ulong, ulong, HttpMethod, int, bool>[17];
private readonly static string[] _methodNames = new string[9];
static HttpUtilities()
{
SetKnownMethod(_mask4Chars, _httpPutMethodLong, HttpMethod.Put, 3);
SetKnownMethod(_mask5Chars, _httpPostMethodLong, HttpMethod.Post, 4);
SetKnownMethod(_mask5Chars, _httpHeadMethodLong, HttpMethod.Head, 4);
SetKnownMethod(_mask6Chars, _httpTraceMethodLong, HttpMethod.Trace, 5);
SetKnownMethod(_mask6Chars, _httpPatchMethodLong, HttpMethod.Patch, 5);
SetKnownMethod(_mask7Chars, _httpDeleteMethodLong, HttpMethod.Delete, 6);
SetKnownMethod(_mask8Chars, _httpConnectMethodLong, HttpMethod.Connect, 7);
SetKnownMethod(_mask8Chars, _httpOptionsMethodLong, HttpMethod.Options, 7);
FillKnownMethodsGaps();
_methodNames[(byte)HttpMethod.Get] = HttpMethods.Get;
_methodNames[(byte)HttpMethod.Put] = HttpMethods.Put;
_methodNames[(byte)HttpMethod.Delete] = HttpMethods.Delete;
_methodNames[(byte)HttpMethod.Post] = HttpMethods.Post;
_methodNames[(byte)HttpMethod.Head] = HttpMethods.Head;
_methodNames[(byte)HttpMethod.Trace] = HttpMethods.Trace;
_methodNames[(byte)HttpMethod.Patch] = HttpMethods.Patch;
_methodNames[(byte)HttpMethod.Connect] = HttpMethods.Connect;
_methodNames[(byte)HttpMethod.Options] = HttpMethods.Options;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int GetKnownMethodIndex(ulong value)
{
const int magicNumer = 0x0600000C;
var tmp = (int)value & magicNumer;
return ((tmp >> 2) | (tmp >> 23)) & 0x0F;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void SetKnownMethod(ulong mask, ulong knownMethodUlong, HttpMethod knownMethod, int length)
{
_knownMethods[GetKnownMethodIndex(knownMethodUlong)] = new Tuple<ulong, ulong, HttpMethod, int, bool>(mask, knownMethodUlong, knownMethod, length, true);
}
private static void FillKnownMethodsGaps()
{
var knownMethods = _knownMethods;
var length = knownMethods.Length;
var invalidHttpMethod = new Tuple<ulong, ulong, HttpMethod, int, bool>(_mask8Chars, 0ul, HttpMethod.Custom, 0, false);
for (int i = 0; i < length; i++)
{
if (knownMethods[i] == null)
{
knownMethods[i] = invalidHttpMethod;
}
}
}
private unsafe static ulong GetAsciiStringAsLong(string str)
{
Debug.Assert(str.Length == 8, "String must be exactly 8 (ASCII) characters long.");
var bytes = Encoding.ASCII.GetBytes(str);
fixed (byte* ptr = &bytes[0])
{
return *(ulong*)ptr;
}
}
private unsafe static uint GetAsciiStringAsInt(string str)
{
Debug.Assert(str.Length == 4, "String must be exactly 4 (ASCII) characters long.");
var bytes = Encoding.ASCII.GetBytes(str);
fixed (byte* ptr = &bytes[0])
{
return *(uint*)ptr;
}
}
private unsafe static ulong GetMaskAsLong(byte[] bytes)
{
Debug.Assert(bytes.Length == 8, "Mask must be exactly 8 bytes long.");
fixed (byte* ptr = bytes)
{
return *(ulong*)ptr;
}
}
public static string GetAsciiStringEscaped(this Span<byte> span, int maxChars)
{
var sb = new StringBuilder();
int i;
for (i = 0; i < Math.Min(span.Length, maxChars); ++i)
{
var ch = span[i];
sb.Append(ch < 0x20 || ch >= 0x7F ? $"<0x{ch:X2}>" : ((char)ch).ToString());
}
if (span.Length > maxChars)
{
sb.Append("...");
}
return sb.ToString();
}
/// <summary>
/// Checks that up to 8 bytes from <paramref name="span"/> correspond to a known HTTP method.
/// </summary>
/// <remarks>
/// A "known HTTP method" can be an HTTP method name defined in the HTTP/1.1 RFC.
/// Since all of those fit in at most 8 bytes, they can be optimally looked up by reading those bytes as a long. Once
/// in that format, it can be checked against the known method.
/// The Known Methods (CONNECT, DELETE, GET, HEAD, PATCH, POST, PUT, OPTIONS, TRACE) are all less than 8 bytes
/// and will be compared with the required space. A mask is used if the Known method is less than 8 bytes.
/// To optimize performance the GET method will be checked first.
/// </remarks>
/// <returns><c>true</c> if the input matches a known string, <c>false</c> otherwise.</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool GetKnownMethod(this Span<byte> span, out HttpMethod method, out int length)
{
if (span.TryRead<uint>(out var possiblyGet))
{
if (possiblyGet == _httpGetMethodInt)
{
length = 3;
method = HttpMethod.Get;
return true;
}
}
if (span.TryRead<ulong>(out var value))
{
var key = GetKnownMethodIndex(value);
var x = _knownMethods[key];
if (x != null && (value & x.Item1) == x.Item2)
{
method = x.Item3;
length = x.Item4;
return x.Item5;
}
}
method = HttpMethod.Custom;
length = 0;
return false;
}
/// <summary>
/// Checks 9 bytes from <paramref name="span"/> correspond to a known HTTP version.
/// </summary>
/// <remarks>
/// A "known HTTP version" Is is either HTTP/1.0 or HTTP/1.1.
/// Since those fit in 8 bytes, they can be optimally looked up by reading those bytes as a long. Once
/// in that format, it can be checked against the known versions.
/// The Known versions will be checked with the required '\r'.
/// To optimize performance the HTTP/1.1 will be checked first.
/// </remarks>
/// <returns><c>true</c> if the input matches a known string, <c>false</c> otherwise.</returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool GetKnownVersion(this Span<byte> span, out HttpVersion knownVersion, out byte length)
{
if (span.TryRead<ulong>(out var version))
{
if (version == _http11VersionLong)
{
length = sizeof(ulong);
knownVersion = HttpVersion.Http11;
}
else if (version == _http10VersionLong)
{
length = sizeof(ulong);
knownVersion = HttpVersion.Http10;
}
else
{
length = 0;
knownVersion = HttpVersion.Unknown;
return false;
}
if (span[sizeof(ulong)] == (byte)'\r')
{
return true;
}
}
knownVersion = HttpVersion.Unknown;
length = 0;
return false;
}
public static string VersionToString(HttpVersion httpVersion)
{
switch (httpVersion)
{
case HttpVersion.Http10:
return Http10Version;
case HttpVersion.Http11:
return Http11Version;
default:
return null;
}
}
public static string MethodToString(HttpMethod method)
{
int methodIndex = (int)method;
if (methodIndex >= 0 && methodIndex <= 8)
{
return _methodNames[methodIndex];
}
return null;
}
}
}