TUN-4597: Add a QUIC server skeleton

- Added a QUIC server to accept streams
- Unit test for this server also tests ALPN
- Temporary echo capability for HTTP ConnectionType

vendor/golang.org/x/sys/cpu/asm_aix_ppc64.s

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build gc
 // +build gc
 
 #include "textflag.h"

vendor/golang.org/x/sys/cpu/cpu_aix.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build aix
 // +build aix
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_arm64.s

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build gc
 // +build gc
 
 #include "textflag.h"

vendor/golang.org/x/sys/cpu/cpu_gc_arm64.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build gc
 // +build gc
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_gc_s390x.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build gc
 // +build gc
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_gc_x86.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build (386 || amd64 || amd64p32) && gc
 // +build 386 amd64 amd64p32
 // +build gc
 
@@ -14,3 +15,7 @@ func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
 // xgetbv with ecx = 0 is implemented in cpu_x86.s for gc compiler
 // and in cpu_gccgo.c for gccgo.
 func xgetbv() (eax, edx uint32)
+
+// darwinSupportsAVX512 is implemented in cpu_x86.s for gc compiler
+// and in cpu_gccgo_x86.go for gccgo.
+func darwinSupportsAVX512() bool

vendor/golang.org/x/sys/cpu/cpu_gccgo_arm64.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build gccgo
 // +build gccgo
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_gccgo_s390x.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build gccgo
 // +build gccgo
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_gccgo_x86.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build (386 || amd64 || amd64p32) && gccgo
 // +build 386 amd64 amd64p32
 // +build gccgo
 
@@ -24,3 +25,9 @@ func xgetbv() (eax, edx uint32) {
 	gccgoXgetbv(&a, &d)
 	return a, d
 }
+
+// gccgo doesn't build on Darwin, per:
+// https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/gcc.rb#L76
+func darwinSupportsAVX512() bool {
+	return false
+}

vendor/golang.org/x/sys/cpu/cpu_linux.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !386 && !amd64 && !amd64p32 && !arm64
 // +build !386,!amd64,!amd64p32,!arm64
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_linux_mips64x.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build linux && (mips64 || mips64le)
 // +build linux
 // +build mips64 mips64le
 

vendor/golang.org/x/sys/cpu/cpu_linux_noinit.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build linux && !arm && !arm64 && !mips64 && !mips64le && !ppc64 && !ppc64le && !s390x
 // +build linux,!arm,!arm64,!mips64,!mips64le,!ppc64,!ppc64le,!s390x
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_linux_ppc64x.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build linux && (ppc64 || ppc64le)
 // +build linux
 // +build ppc64 ppc64le
 

vendor/golang.org/x/sys/cpu/cpu_mips64x.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build mips64 || mips64le
 // +build mips64 mips64le
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_mipsx.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build mips || mipsle
 // +build mips mipsle
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_other_arm.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !linux && arm
 // +build !linux,arm
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_other_arm64.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !linux,!netbsd
-// +build arm64
+//go:build !linux && !netbsd && arm64
+// +build !linux,!netbsd,arm64
 
 package cpu
 

vendor/golang.org/x/sys/cpu/cpu_other_mips64x.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !linux && (mips64 || mips64le)
 // +build !linux
 // +build mips64 mips64le
 

vendor/golang.org/x/sys/cpu/cpu_ppc64x.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build ppc64 || ppc64le
 // +build ppc64 ppc64le
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_riscv64.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build riscv64
 // +build riscv64
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_s390x.s

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build gc
 // +build gc
 
 #include "textflag.h"

vendor/golang.org/x/sys/cpu/cpu_wasm.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build wasm
 // +build wasm
 
 package cpu

vendor/golang.org/x/sys/cpu/cpu_x86.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build 386 || amd64 || amd64p32
 // +build 386 amd64 amd64p32
 
 package cpu
@@ -86,8 +87,14 @@ func archInit() {
 		// Check if XMM and YMM registers have OS support.
 		osSupportsAVX = isSet(1, eax) && isSet(2, eax)
 
-		// Check if OPMASK and ZMM registers have OS support.
-		osSupportsAVX512 = osSupportsAVX && isSet(5, eax) && isSet(6, eax) && isSet(7, eax)
+		if runtime.GOOS == "darwin" {
+			// Check darwin commpage for AVX512 support. Necessary because:
+			// https://github.com/apple/darwin-xnu/blob/0a798f6738bc1db01281fc08ae024145e84df927/osfmk/i386/fpu.c#L175-L201
+			osSupportsAVX512 = osSupportsAVX && darwinSupportsAVX512()
+		} else {
+			// Check if OPMASK and ZMM registers have OS support.
+			osSupportsAVX512 = osSupportsAVX && isSet(5, eax) && isSet(6, eax) && isSet(7, eax)
+		}
 	}
 
 	X86.HasAVX = isSet(28, ecx1) && osSupportsAVX

vendor/golang.org/x/sys/cpu/cpu_x86.s

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build (386 || amd64 || amd64p32) && gc
 // +build 386 amd64 amd64p32
 // +build gc
 
@@ -25,3 +26,27 @@ TEXT ·xgetbv(SB),NOSPLIT,$0-8
 	MOVL AX, eax+0(FP)
 	MOVL DX, edx+4(FP)
 	RET
+
+// func darwinSupportsAVX512() bool
+TEXT ·darwinSupportsAVX512(SB), NOSPLIT, $0-1
+    MOVB    $0, ret+0(FP) // default to false
+#ifdef GOOS_darwin   // return if not darwin
+#ifdef GOARCH_amd64  // return if not amd64
+// These values from:
+// https://github.com/apple/darwin-xnu/blob/xnu-4570.1.46/osfmk/i386/cpu_capabilities.h
+#define commpage64_base_address         0x00007fffffe00000
+#define commpage64_cpu_capabilities64   (commpage64_base_address+0x010)
+#define commpage64_version              (commpage64_base_address+0x01E)
+#define hasAVX512F                      0x0000004000000000
+    MOVQ    $commpage64_version, BX
+    CMPW    (BX), $13  // cpu_capabilities64 undefined in versions < 13
+    JL      no_avx512
+    MOVQ    $commpage64_cpu_capabilities64, BX
+    MOVQ    $hasAVX512F, CX
+    TESTQ   (BX), CX
+    JZ      no_avx512
+    MOVB    $1, ret+0(FP)
+no_avx512:
+#endif
+#endif
+    RET

vendor/golang.org/x/sys/cpu/syscall_aix_gccgo.go

@@ -8,8 +8,8 @@
 // Morever, this file will be used during the building of
 // gccgo's libgo and thus must not used a CGo method.
 
-// +build aix
-// +build gccgo
+//go:build aix && gccgo
+// +build aix,gccgo
 
 package cpu
 

vendor/golang.org/x/sys/cpu/syscall_aix_ppc64_gc.go

@@ -6,8 +6,8 @@
 // system call on AIX without depending on x/sys/unix.
 // (See golang.org/issue/32102)
 
-// +build aix,ppc64
-// +build gc
+//go:build aix && ppc64 && gc
+// +build aix,ppc64,gc
 
 package cpu