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Unload MsQuic after checking for QUIC support to free resources. #74749

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merged 3 commits into from
Sep 1, 2022
Merged

Unload MsQuic after checking for QUIC support to free resources. #74749

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fee1c6d
Unload MsQuic after checking for QUIC support to free resources.
rzikm Aug 29, 2022
bf47ac0
Unload MsQuic unconditionally
rzikm Aug 31, 2022
162c331
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rzikm Sep 1, 2022
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83 changes: 59 additions & 24 deletions src/libraries/System.Net.Quic/src/System/Net/Quic/Internal/MsQuicApi.cs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.InteropServices;
using Microsoft.Quic;
Expand Down Expand Up @@ -47,7 +48,8 @@ private MsQuicApi(QUIC_API_TABLE* apiTable)
}
}

internal static MsQuicApi Api { get; } = null!;
internal static Lazy<MsQuicApi> _api = new Lazy<MsQuicApi>(AllocateMsQuicApi);
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private readonly?

internal static MsQuicApi Api => _api.Value;

internal static bool IsQuicSupported { get; }

Expand All @@ -58,29 +60,21 @@ private MsQuicApi(QUIC_API_TABLE* apiTable)

static MsQuicApi()
{
IntPtr msQuicHandle;
if (!NativeLibrary.TryLoad($"{Interop.Libraries.MsQuic}.{MsQuicVersion.Major}", typeof(MsQuicApi).Assembly, DllImportSearchPath.AssemblyDirectory, out msQuicHandle) &&
!NativeLibrary.TryLoad(Interop.Libraries.MsQuic, typeof(MsQuicApi).Assembly, DllImportSearchPath.AssemblyDirectory, out msQuicHandle))
if (!TryLoadMsQuic(out IntPtr msQuicHandle))
{
return;
}

try
{
if (!NativeLibrary.TryGetExport(msQuicHandle, "MsQuicOpenVersion", out IntPtr msQuicOpenVersionAddress))
{
return;
}

QUIC_API_TABLE* apiTable = null;
delegate* unmanaged[Cdecl]<uint, QUIC_API_TABLE**, int> msQuicOpenVersion = (delegate* unmanaged[Cdecl]<uint, QUIC_API_TABLE**, int>)msQuicOpenVersionAddress;
if (StatusFailed(msQuicOpenVersion((uint)MsQuicVersion.Major, &apiTable)))
if (!TryOpenMsQuic(msQuicHandle, out QUIC_API_TABLE* apiTable))
{
return;
}

try
{
// check version
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Uber nitty nit 😄

Suggested change
// check version
// Check version

int arraySize = 4;
uint* libVersion = stackalloc uint[arraySize];
uint size = (uint)arraySize * sizeof(uint);
Expand All @@ -99,7 +93,7 @@ static MsQuicApi()
return;
}

// Assume SChannel is being used on windows and query for the actual provider from the library
// Assume SChannel is being used on windows and query for the actual provider from the library if querying is supported
QUIC_TLS_PROVIDER provider = OperatingSystem.IsWindows() ? QUIC_TLS_PROVIDER.SCHANNEL : QUIC_TLS_PROVIDER.OPENSSL;
size = sizeof(QUIC_TLS_PROVIDER);
apiTable->GetParam(null, QUIC_PARAM_GLOBAL_TLS_PROVIDER, &size, &provider);
Expand All @@ -122,26 +116,67 @@ static MsQuicApi()
Tls13ClientMayBeDisabled = IsTls13Disabled(isServer: false);
}

Api = new MsQuicApi(apiTable);
IsQuicSupported = true;
}
finally
{
if (!IsQuicSupported && NativeLibrary.TryGetExport(msQuicHandle, "MsQuicClose", out IntPtr msQuicClose))
{
// Gracefully close the API table
((delegate* unmanaged[Cdecl]<QUIC_API_TABLE*, void>)msQuicClose)(apiTable);
}
// Gracefully close the API table to free resources. The API table will be allocated lazily again if needed
bool closed = TryCloseMsQuic(msQuicHandle, apiTable);
Debug.Assert(closed, "Failed to close MsQuic");
}

}
finally
{
if (!IsQuicSupported)
{
NativeLibrary.Free(msQuicHandle);
}
// Unload the library, we will load it again when we actually use QUIC
NativeLibrary.Free(msQuicHandle);
}
}

internal static MsQuicApi AllocateMsQuicApi()
{
Debug.Assert(IsQuicSupported);

if (TryLoadMsQuic(out IntPtr msQuicHandle) &&
TryOpenMsQuic(msQuicHandle, out QUIC_API_TABLE* apiTable))
{
return new MsQuicApi(apiTable);
}

throw new Exception("Failed to create MsQuicApi instance");
}

internal static bool TryLoadMsQuic(out IntPtr msQuicHandle) =>
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Should those be private?

NativeLibrary.TryLoad($"{Interop.Libraries.MsQuic}.{MsQuicVersion.Major}", typeof(MsQuicApi).Assembly, DllImportSearchPath.AssemblyDirectory, out msQuicHandle) ||
NativeLibrary.TryLoad(Interop.Libraries.MsQuic, typeof(MsQuicApi).Assembly, DllImportSearchPath.AssemblyDirectory, out msQuicHandle);

internal static bool TryOpenMsQuic(IntPtr msQuicHandle, out QUIC_API_TABLE* apiTable)
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We could alternatively use [LibraryImport] for MsQuicOpenVersion and MsQuicClose, it might clean up the code a bit at the cost of not being able to unload the lib from the process I think (if we care about that)

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They already have imports in:

runtime/src/libraries/System.Net.Quic/src/System/Net/Quic/Interop/msquic_generated.cs

Line 2593 in bf47ac0

internal static extern int MsQuicOpenVersion([NativeTypeName("uint32_t")] uint Version, [NativeTypeName("const void **")] void** QuicApi);

I'm not an expert on this, but we control which version of libmsquic we're loading in TryLoadMsQuic and we do an attempt to load it that would not fail if the lib is not present. I'm not sure we can achieve the same with the import. Relevant history: #49973

Anyway, we might at least use nameof(MsQuicOpenVersion) from the generated interop. Though we lived with the string until now, so it's certainly not critical.

{
apiTable = null;
if (!NativeLibrary.TryGetExport(msQuicHandle, "MsQuicOpenVersion", out IntPtr msQuicOpenVersionAddress))
{
return false;
}

QUIC_API_TABLE* table = null;
delegate* unmanaged[Cdecl]<uint, QUIC_API_TABLE**, int> msQuicOpenVersion = (delegate* unmanaged[Cdecl]<uint, QUIC_API_TABLE**, int>)msQuicOpenVersionAddress;
if (StatusFailed(msQuicOpenVersion((uint)MsQuicVersion.Major, &table)))
{
return false;
}

apiTable = table;
return true;
}

internal static bool TryCloseMsQuic(IntPtr msQuicHandle, QUIC_API_TABLE* apiTable)
{
if (NativeLibrary.TryGetExport(msQuicHandle, "MsQuicClose", out IntPtr msQuicClose))
{
((delegate* unmanaged[Cdecl]<QUIC_API_TABLE*, void>)msQuicClose)(apiTable);
return true;
}

return false;
}

private static bool IsWindowsVersionSupported() => OperatingSystem.IsWindowsVersionAtLeast(MinWindowsVersion.Major,
Expand Down