feat: Add HTTP2 for unencrypted HTTP

Signed-off-by: erezrokah <erezrokah@users.noreply.github.com>

configuration/configuration.go

@@ -157,9 +157,15 @@ type Configuration struct {
 		// HTTP2 configuration options
 		HTTP2 struct {
 			// Specifies whether the registry should disallow clients attempting
-			// to connect via http2. If set to true, only http/1.1 is supported.
+			// to connect via HTTP/2. If set to true, only HTTP/1.1 is supported.
 			Disabled bool `yaml:"disabled,omitempty"`
 		} `yaml:"http2,omitempty"`
+
+		H2C struct {
+			// Enables H2C (HTTP/2 Cleartext). Enable to support HTTP/2 without needing to configure TLS
+			// Useful when deploying the registry behind a load balancer (e.g. Cloud Run)
+			Enabled bool `yaml:"enabled,omitempty"`
+		} `yaml:"h2c,omitempty"`
 	} `yaml:"http,omitempty"`
 
 	// Notifications specifies configuration about various endpoint to which

configuration/configuration_test.go

@@ -97,6 +97,9 @@ var configStruct = Configuration{
 		HTTP2 struct {
 			Disabled bool `yaml:"disabled,omitempty"`
 		} `yaml:"http2,omitempty"`
+		H2C struct {
+			Enabled bool `yaml:"enabled,omitempty"`
+		} `yaml:"h2c,omitempty"`
 	}{
 		TLS: struct {
 			Certificate  string   `yaml:"certificate,omitempty"`
@@ -121,6 +124,11 @@ var configStruct = Configuration{
 		}{
 			Disabled: false,
 		},
+		H2C: struct {
+			Enabled bool `yaml:"enabled,omitempty"`
+		}{
+			Enabled: true,
+		},
 	},
 	Redis: Redis{
 		Addr:     "localhost:6379",

docs/content/about/configuration.md

@@ -220,6 +220,8 @@ http:
     X-Content-Type-Options: [nosniff]
   http2:
     disabled: false
+  h2c:
+    enabled: false
 notifications:
   events:
     includereferences: true
@@ -724,6 +726,8 @@ http:
     X-Content-Type-Options: [nosniff]
   http2:
     disabled: false
+  h2c:
+    enabled: false
 ```
 
 The `http` option details the configuration for the HTTP server that hosts the
@@ -870,13 +874,24 @@ registry. This header is included in the example configuration file.
 
 ### `http2`
 
-The `http2` structure within `http` is **optional**. Use this to control http2
+The `http2` structure within `http` is **optional**. Use this to control HTTP/2 over TLS
 settings for the registry.
+If `tls` is not configured this option is ignored. To enable HTTP/2 over non TLS connections use `h2c` instead.
 
 | Parameter | Required | Description                                           |
 |-----------|----------|-------------------------------------------------------|
 | `disabled` | no      | If `true`, then `http2` support is disabled.          |
 
+### `h2c`
+
+The `h2c` structure within `http` is **optional**. Use this to control H2C (HTTP/2 Cleartext)
+settings for the registry.
+Useful when deploying the registry behind a load balancer (e.g. Google Cloud Run)
+
+| Parameter | Required | Description                                           |
+|-----------|----------|-------------------------------------------------------|
+| `enabled` | no      | If `true`, then `h2c` support is enabled.              |
+
 ## `notifications`
 
 ```yaml

go.mod

@@ -30,7 +30,7 @@ require (
 	github.com/stretchr/testify v1.8.4
 	go.opentelemetry.io/contrib/exporters/autoexport v0.46.1
 	go.opentelemetry.io/otel/sdk v1.21.0
-	golang.org/x/crypto v0.17.0
+	golang.org/x/crypto v0.18.0
 	golang.org/x/oauth2 v0.11.0
 	google.golang.org/api v0.126.0
 	gopkg.in/yaml.v2 v2.4.0
@@ -87,9 +87,9 @@ require (
 	go.opentelemetry.io/otel/sdk/metric v1.21.0 // indirect
 	go.opentelemetry.io/otel/trace v1.21.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.0.0 // indirect
-	golang.org/x/net v0.18.0 // indirect
+	golang.org/x/net v0.20.0
 	golang.org/x/sync v0.3.0 // indirect
-	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/sys v0.16.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 // indirect
 	google.golang.org/appengine v1.6.7 // indirect

go.sum

@@ -280,8 +280,8 @@ golang.org/x/crypto v0.0.0-20190911031432-227b76d455e7/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.0.0-20220314234659-1baeb1ce4c0b/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
-golang.org/x/crypto v0.17.0 h1:r8bRNjWL3GshPW3gkd+RpvzWrZAwPS49OmTGZ/uhM4k=
+golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
-golang.org/x/crypto v0.17.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4=
+golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
@@ -302,8 +302,8 @@ golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwY
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
-golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
+golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
-golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=
+golang.org/x/net v0.20.0/go.mod h1:z8BVo6PvndSri0LbOE3hAn0apkU+1YvI6E70E9jsnvY=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.11.0 h1:vPL4xzxBM4niKCW6g9whtaWVXTJf1U5e4aZxxFx/gbU=
@@ -332,8 +332,8 @@ golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
-golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

registry/registry.go

@@ -20,6 +20,8 @@ import (
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"golang.org/x/crypto/acme"
 	"golang.org/x/crypto/acme/autocert"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
 
 	"github.com/distribution/distribution/v3/configuration"
 	"github.com/distribution/distribution/v3/health"
@@ -158,6 +160,9 @@ func NewRegistry(ctx context.Context, config *configuration.Configuration) (*Reg
 	if err != nil {
 		return nil, fmt.Errorf("error during open telemetry initialization: %v", err)
 	}
+	if config.HTTP.H2C.Enabled {
+		handler = h2c.NewHandler(handler, &http2.Server{})
+	}
 	handler = otelHandler(handler)
 
 	server := &http.Server{

vendor/golang.org/x/crypto/internal/poly1305/bits_compat.go

@@ -1,39 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build !go1.13
-
-package poly1305
-
-// Generic fallbacks for the math/bits intrinsics, copied from
-// src/math/bits/bits.go. They were added in Go 1.12, but Add64 and Sum64 had
-// variable time fallbacks until Go 1.13.
-
-func bitsAdd64(x, y, carry uint64) (sum, carryOut uint64) {
-	sum = x + y + carry
-	carryOut = ((x & y) | ((x | y) &^ sum)) >> 63
-	return
-}
-
-func bitsSub64(x, y, borrow uint64) (diff, borrowOut uint64) {
-	diff = x - y - borrow
-	borrowOut = ((^x & y) | (^(x ^ y) & diff)) >> 63
-	return
-}
-
-func bitsMul64(x, y uint64) (hi, lo uint64) {
-	const mask32 = 1<<32 - 1
-	x0 := x & mask32
-	x1 := x >> 32
-	y0 := y & mask32
-	y1 := y >> 32
-	w0 := x0 * y0
-	t := x1*y0 + w0>>32
-	w1 := t & mask32
-	w2 := t >> 32
-	w1 += x0 * y1
-	hi = x1*y1 + w2 + w1>>32
-	lo = x * y
-	return
-}

vendor/golang.org/x/crypto/internal/poly1305/bits_go1.13.go

@@ -1,21 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build go1.13
-
-package poly1305
-
-import "math/bits"
-
-func bitsAdd64(x, y, carry uint64) (sum, carryOut uint64) {
-	return bits.Add64(x, y, carry)
-}
-
-func bitsSub64(x, y, borrow uint64) (diff, borrowOut uint64) {
-	return bits.Sub64(x, y, borrow)
-}
-
-func bitsMul64(x, y uint64) (hi, lo uint64) {
-	return bits.Mul64(x, y)
-}

vendor/golang.org/x/crypto/internal/poly1305/sum_generic.go

@@ -7,7 +7,10 @@
 
 package poly1305
 
-import "encoding/binary"
+import (
+	"encoding/binary"
+	"math/bits"
+)
 
 // Poly1305 [RFC 7539] is a relatively simple algorithm: the authentication tag
 // for a 64 bytes message is approximately
@@ -114,13 +117,13 @@ type uint128 struct {
 }
 
 func mul64(a, b uint64) uint128 {
-	hi, lo := bitsMul64(a, b)
+	hi, lo := bits.Mul64(a, b)
 	return uint128{lo, hi}
 }
 
 func add128(a, b uint128) uint128 {
-	lo, c := bitsAdd64(a.lo, b.lo, 0)
+	lo, c := bits.Add64(a.lo, b.lo, 0)
-	hi, c := bitsAdd64(a.hi, b.hi, c)
+	hi, c := bits.Add64(a.hi, b.hi, c)
 	if c != 0 {
 		panic("poly1305: unexpected overflow")
 	}
@@ -155,8 +158,8 @@ func updateGeneric(state *macState, msg []byte) {
 		// hide leading zeroes. For full chunks, that's 1 << 128, so we can just
 		// add 1 to the most significant (2¹²⁸) limb, h2.
 		if len(msg) >= TagSize {
-			h0, c = bitsAdd64(h0, binary.LittleEndian.Uint64(msg[0:8]), 0)
+			h0, c = bits.Add64(h0, binary.LittleEndian.Uint64(msg[0:8]), 0)
-			h1, c = bitsAdd64(h1, binary.LittleEndian.Uint64(msg[8:16]), c)
+			h1, c = bits.Add64(h1, binary.LittleEndian.Uint64(msg[8:16]), c)
 			h2 += c + 1
 
 			msg = msg[TagSize:]
@@ -165,8 +168,8 @@ func updateGeneric(state *macState, msg []byte) {
 			copy(buf[:], msg)
 			buf[len(msg)] = 1
 
-			h0, c = bitsAdd64(h0, binary.LittleEndian.Uint64(buf[0:8]), 0)
+			h0, c = bits.Add64(h0, binary.LittleEndian.Uint64(buf[0:8]), 0)
-			h1, c = bitsAdd64(h1, binary.LittleEndian.Uint64(buf[8:16]), c)
+			h1, c = bits.Add64(h1, binary.LittleEndian.Uint64(buf[8:16]), c)
 			h2 += c
 
 			msg = nil
@@ -219,9 +222,9 @@ func updateGeneric(state *macState, msg []byte) {
 		m3 := h2r1
 
 		t0 := m0.lo
-		t1, c := bitsAdd64(m1.lo, m0.hi, 0)
+		t1, c := bits.Add64(m1.lo, m0.hi, 0)
-		t2, c := bitsAdd64(m2.lo, m1.hi, c)
+		t2, c := bits.Add64(m2.lo, m1.hi, c)
-		t3, _ := bitsAdd64(m3.lo, m2.hi, c)
+		t3, _ := bits.Add64(m3.lo, m2.hi, c)
 
 		// Now we have the result as 4 64-bit limbs, and we need to reduce it
 		// modulo 2¹³⁰ - 5. The special shape of this Crandall prime lets us do
@@ -243,14 +246,14 @@ func updateGeneric(state *macState, msg []byte) {
 
 		// To add c * 5 to h, we first add cc = c * 4, and then add (cc >> 2) = c.
 
-		h0, c = bitsAdd64(h0, cc.lo, 0)
+		h0, c = bits.Add64(h0, cc.lo, 0)
-		h1, c = bitsAdd64(h1, cc.hi, c)
+		h1, c = bits.Add64(h1, cc.hi, c)
 		h2 += c
 
 		cc = shiftRightBy2(cc)
 
-		h0, c = bitsAdd64(h0, cc.lo, 0)
+		h0, c = bits.Add64(h0, cc.lo, 0)
-		h1, c = bitsAdd64(h1, cc.hi, c)
+		h1, c = bits.Add64(h1, cc.hi, c)
 		h2 += c
 
 		// h2 is at most 3 + 1 + 1 = 5, making the whole of h at most
@@ -287,9 +290,9 @@ func finalize(out *[TagSize]byte, h *[3]uint64, s *[2]uint64) {
 	// in constant time, we compute t = h - (2¹³⁰ - 5), and select h as the
 	// result if the subtraction underflows, and t otherwise.
 
-	hMinusP0, b := bitsSub64(h0, p0, 0)
+	hMinusP0, b := bits.Sub64(h0, p0, 0)
-	hMinusP1, b := bitsSub64(h1, p1, b)
+	hMinusP1, b := bits.Sub64(h1, p1, b)
-	_, b = bitsSub64(h2, p2, b)
+	_, b = bits.Sub64(h2, p2, b)
 
 	// h = h if h < p else h - p
 	h0 = select64(b, h0, hMinusP0)
@@ -301,8 +304,8 @@ func finalize(out *[TagSize]byte, h *[3]uint64, s *[2]uint64) {
 	//
 	// by just doing a wide addition with the 128 low bits of h and discarding
 	// the overflow.
-	h0, c := bitsAdd64(h0, s[0], 0)
+	h0, c := bits.Add64(h0, s[0], 0)
-	h1, _ = bitsAdd64(h1, s[1], c)
+	h1, _ = bits.Add64(h1, s[1], c)
 
 	binary.LittleEndian.PutUint64(out[0:8], h0)
 	binary.LittleEndian.PutUint64(out[8:16], h1)

vendor/golang.org/x/net/http2/h2c/h2c.go

@@ -0,0 +1,240 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package h2c implements the unencrypted "h2c" form of HTTP/2.
+//
+// The h2c protocol is the non-TLS version of HTTP/2 which is not available from
+// net/http or golang.org/x/net/http2.
+package h2c
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"net/textproto"
+	"os"
+	"strings"
+
+	"golang.org/x/net/http/httpguts"
+	"golang.org/x/net/http2"
+)
+
+var (
+	http2VerboseLogs bool
+)
+
+func init() {
+	e := os.Getenv("GODEBUG")
+	if strings.Contains(e, "http2debug=1") || strings.Contains(e, "http2debug=2") {
+		http2VerboseLogs = true
+	}
+}
+
+// h2cHandler is a Handler which implements h2c by hijacking the HTTP/1 traffic
+// that should be h2c traffic. There are two ways to begin a h2c connection
+// (RFC 7540 Section 3.2 and 3.4): (1) Starting with Prior Knowledge - this
+// works by starting an h2c connection with a string of bytes that is valid
+// HTTP/1, but unlikely to occur in practice and (2) Upgrading from HTTP/1 to
+// h2c - this works by using the HTTP/1 Upgrade header to request an upgrade to
+// h2c. When either of those situations occur we hijack the HTTP/1 connection,
+// convert it to an HTTP/2 connection and pass the net.Conn to http2.ServeConn.
+type h2cHandler struct {
+	Handler http.Handler
+	s       *http2.Server
+}
+
+// NewHandler returns an http.Handler that wraps h, intercepting any h2c
+// traffic. If a request is an h2c connection, it's hijacked and redirected to
+// s.ServeConn. Otherwise the returned Handler just forwards requests to h. This
+// works because h2c is designed to be parseable as valid HTTP/1, but ignored by
+// any HTTP server that does not handle h2c. Therefore we leverage the HTTP/1
+// compatible parts of the Go http library to parse and recognize h2c requests.
+// Once a request is recognized as h2c, we hijack the connection and convert it
+// to an HTTP/2 connection which is understandable to s.ServeConn. (s.ServeConn
+// understands HTTP/2 except for the h2c part of it.)
+//
+// The first request on an h2c connection is read entirely into memory before
+// the Handler is called. To limit the memory consumed by this request, wrap
+// the result of NewHandler in an http.MaxBytesHandler.
+func NewHandler(h http.Handler, s *http2.Server) http.Handler {
+	return &h2cHandler{
+		Handler: h,
+		s:       s,
+	}
+}
+
+// extractServer extracts existing http.Server instance from http.Request or create an empty http.Server
+func extractServer(r *http.Request) *http.Server {
+	server, ok := r.Context().Value(http.ServerContextKey).(*http.Server)
+	if ok {
+		return server
+	}
+	return new(http.Server)
+}
+
+// ServeHTTP implement the h2c support that is enabled by h2c.GetH2CHandler.
+func (s h2cHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Handle h2c with prior knowledge (RFC 7540 Section 3.4)
+	if r.Method == "PRI" && len(r.Header) == 0 && r.URL.Path == "*" && r.Proto == "HTTP/2.0" {
+		if http2VerboseLogs {
+			log.Print("h2c: attempting h2c with prior knowledge.")
+		}
+		conn, err := initH2CWithPriorKnowledge(w)
+		if err != nil {
+			if http2VerboseLogs {
+				log.Printf("h2c: error h2c with prior knowledge: %v", err)
+			}
+			return
+		}
+		defer conn.Close()
+		s.s.ServeConn(conn, &http2.ServeConnOpts{
+			Context:          r.Context(),
+			BaseConfig:       extractServer(r),
+			Handler:          s.Handler,
+			SawClientPreface: true,
+		})
+		return
+	}
+	// Handle Upgrade to h2c (RFC 7540 Section 3.2)
+	if isH2CUpgrade(r.Header) {
+		conn, settings, err := h2cUpgrade(w, r)
+		if err != nil {
+			if http2VerboseLogs {
+				log.Printf("h2c: error h2c upgrade: %v", err)
+			}
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		defer conn.Close()
+		s.s.ServeConn(conn, &http2.ServeConnOpts{
+			Context:        r.Context(),
+			BaseConfig:     extractServer(r),
+			Handler:        s.Handler,
+			UpgradeRequest: r,
+			Settings:       settings,
+		})
+		return
+	}
+	s.Handler.ServeHTTP(w, r)
+	return
+}
+
+// initH2CWithPriorKnowledge implements creating a h2c connection with prior
+// knowledge (Section 3.4) and creates a net.Conn suitable for http2.ServeConn.
+// All we have to do is look for the client preface that is suppose to be part
+// of the body, and reforward the client preface on the net.Conn this function
+// creates.
+func initH2CWithPriorKnowledge(w http.ResponseWriter) (net.Conn, error) {
+	hijacker, ok := w.(http.Hijacker)
+	if !ok {
+		return nil, errors.New("h2c: connection does not support Hijack")
+	}
+	conn, rw, err := hijacker.Hijack()
+	if err != nil {
+		return nil, err
+	}
+
+	const expectedBody = "SM\r\n\r\n"
+
+	buf := make([]byte, len(expectedBody))
+	n, err := io.ReadFull(rw, buf)
+	if err != nil {
+		return nil, fmt.Errorf("h2c: error reading client preface: %s", err)
+	}
+
+	if string(buf[:n]) == expectedBody {
+		return newBufConn(conn, rw), nil
+	}
+
+	conn.Close()
+	return nil, errors.New("h2c: invalid client preface")
+}
+
+// h2cUpgrade establishes a h2c connection using the HTTP/1 upgrade (Section 3.2).
+func h2cUpgrade(w http.ResponseWriter, r *http.Request) (_ net.Conn, settings []byte, err error) {
+	settings, err = getH2Settings(r.Header)
+	if err != nil {
+		return nil, nil, err
+	}
+	hijacker, ok := w.(http.Hijacker)
+	if !ok {
+		return nil, nil, errors.New("h2c: connection does not support Hijack")
+	}
+
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		return nil, nil, err
+	}
+	r.Body = io.NopCloser(bytes.NewBuffer(body))
+
+	conn, rw, err := hijacker.Hijack()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	rw.Write([]byte("HTTP/1.1 101 Switching Protocols\r\n" +
+		"Connection: Upgrade\r\n" +
+		"Upgrade: h2c\r\n\r\n"))
+	return newBufConn(conn, rw), settings, nil
+}
+
+// isH2CUpgrade returns true if the header properly request an upgrade to h2c
+// as specified by Section 3.2.
+func isH2CUpgrade(h http.Header) bool {
+	return httpguts.HeaderValuesContainsToken(h[textproto.CanonicalMIMEHeaderKey("Upgrade")], "h2c") &&
+		httpguts.HeaderValuesContainsToken(h[textproto.CanonicalMIMEHeaderKey("Connection")], "HTTP2-Settings")
+}
+
+// getH2Settings returns the settings in the HTTP2-Settings header.
+func getH2Settings(h http.Header) ([]byte, error) {
+	vals, ok := h[textproto.CanonicalMIMEHeaderKey("HTTP2-Settings")]
+	if !ok {
+		return nil, errors.New("missing HTTP2-Settings header")
+	}
+	if len(vals) != 1 {
+		return nil, fmt.Errorf("expected 1 HTTP2-Settings. Got: %v", vals)
+	}
+	settings, err := base64.RawURLEncoding.DecodeString(vals[0])
+	if err != nil {
+		return nil, err
+	}
+	return settings, nil
+}
+
+func newBufConn(conn net.Conn, rw *bufio.ReadWriter) net.Conn {
+	rw.Flush()
+	if rw.Reader.Buffered() == 0 {
+		// If there's no buffered data to be read,
+		// we can just discard the bufio.ReadWriter.
+		return conn
+	}
+	return &bufConn{conn, rw.Reader}
+}
+
+// bufConn wraps a net.Conn, but reads drain the bufio.Reader first.
+type bufConn struct {
+	net.Conn
+	*bufio.Reader
+}
+
+func (c *bufConn) Read(p []byte) (int, error) {
+	if c.Reader == nil {
+		return c.Conn.Read(p)
+	}
+	n := c.Reader.Buffered()
+	if n == 0 {
+		c.Reader = nil
+		return c.Conn.Read(p)
+	}
+	if n < len(p) {
+		p = p[:n]
+	}
+	return c.Reader.Read(p)
+}

vendor/golang.org/x/sys/unix/mkerrors.sh

@@ -248,6 +248,7 @@ struct ltchars {
 #include <linux/module.h>
 #include <linux/mount.h>
 #include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nf_tables.h>
 #include <linux/netlink.h>
 #include <linux/net_namespace.h>
 #include <linux/nfc.h>
@@ -283,10 +284,6 @@ struct ltchars {
 #include <asm/termbits.h>
 #endif
 
-#ifndef MSG_FASTOPEN
-#define MSG_FASTOPEN    0x20000000
-#endif
-
 #ifndef PTRACE_GETREGS
 #define PTRACE_GETREGS	0xc
 #endif
@@ -295,14 +292,6 @@ struct ltchars {
 #define PTRACE_SETREGS	0xd
 #endif
 
-#ifndef SOL_NETLINK
-#define SOL_NETLINK	270
-#endif
-
-#ifndef SOL_SMC
-#define SOL_SMC 286
-#endif
-
 #ifdef SOL_BLUETOOTH
 // SPARC includes this in /usr/include/sparc64-linux-gnu/bits/socket.h
 // but it is already in bluetooth_linux.go
@@ -319,10 +308,23 @@ struct ltchars {
 #undef TIPC_WAIT_FOREVER
 #define TIPC_WAIT_FOREVER 0xffffffff
 
-// Copied from linux/l2tp.h
+// Copied from linux/netfilter/nf_nat.h
-// Including linux/l2tp.h here causes conflicts between linux/in.h
+// Including linux/netfilter/nf_nat.h here causes conflicts between linux/in.h
-// and netinet/in.h included via net/route.h above.
+// and netinet/in.h.
-#define IPPROTO_L2TP		115
+#define NF_NAT_RANGE_MAP_IPS			(1 << 0)
+#define NF_NAT_RANGE_PROTO_SPECIFIED		(1 << 1)
+#define NF_NAT_RANGE_PROTO_RANDOM		(1 << 2)
+#define NF_NAT_RANGE_PERSISTENT			(1 << 3)
+#define NF_NAT_RANGE_PROTO_RANDOM_FULLY		(1 << 4)
+#define NF_NAT_RANGE_PROTO_OFFSET		(1 << 5)
+#define NF_NAT_RANGE_NETMAP			(1 << 6)
+#define NF_NAT_RANGE_PROTO_RANDOM_ALL		\
+	(NF_NAT_RANGE_PROTO_RANDOM | NF_NAT_RANGE_PROTO_RANDOM_FULLY)
+#define NF_NAT_RANGE_MASK					\
+	(NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED |	\
+	 NF_NAT_RANGE_PROTO_RANDOM | NF_NAT_RANGE_PERSISTENT |	\
+	 NF_NAT_RANGE_PROTO_RANDOM_FULLY | NF_NAT_RANGE_PROTO_OFFSET | \
+	 NF_NAT_RANGE_NETMAP)
 
 // Copied from linux/hid.h.
 // Keep in sync with the size of the referenced fields.
@@ -603,6 +605,9 @@ ccflags="$@"
 		$2 ~ /^FSOPT_/ ||
 		$2 ~ /^WDIO[CFS]_/ ||
 		$2 ~ /^NFN/ ||
+		$2 !~ /^NFT_META_IIFTYPE/ &&
+		$2 ~ /^NFT_/ ||
+		$2 ~ /^NF_NAT_/ ||
 		$2 ~ /^XDP_/ ||
 		$2 ~ /^RWF_/ ||
 		$2 ~ /^(HDIO|WIN|SMART)_/ ||

vendor/golang.org/x/sys/unix/zerrors_linux.go

@@ -2127,6 +2127,60 @@ const (
 	NFNL_SUBSYS_QUEUE                           = 0x3
 	NFNL_SUBSYS_ULOG                            = 0x4
 	NFS_SUPER_MAGIC                             = 0x6969
+	NFT_CHAIN_FLAGS                             = 0x7
+	NFT_CHAIN_MAXNAMELEN                        = 0x100
+	NFT_CT_MAX                                  = 0x17
+	NFT_DATA_RESERVED_MASK                      = 0xffffff00
+	NFT_DATA_VALUE_MAXLEN                       = 0x40
+	NFT_EXTHDR_OP_MAX                           = 0x4
+	NFT_FIB_RESULT_MAX                          = 0x3
+	NFT_INNER_MASK                              = 0xf
+	NFT_LOGLEVEL_MAX                            = 0x8
+	NFT_NAME_MAXLEN                             = 0x100
+	NFT_NG_MAX                                  = 0x1
+	NFT_OBJECT_CONNLIMIT                        = 0x5
+	NFT_OBJECT_COUNTER                          = 0x1
+	NFT_OBJECT_CT_EXPECT                        = 0x9
+	NFT_OBJECT_CT_HELPER                        = 0x3
+	NFT_OBJECT_CT_TIMEOUT                       = 0x7
+	NFT_OBJECT_LIMIT                            = 0x4
+	NFT_OBJECT_MAX                              = 0xa
+	NFT_OBJECT_QUOTA                            = 0x2
+	NFT_OBJECT_SECMARK                          = 0x8
+	NFT_OBJECT_SYNPROXY                         = 0xa
+	NFT_OBJECT_TUNNEL                           = 0x6
+	NFT_OBJECT_UNSPEC                           = 0x0
+	NFT_OBJ_MAXNAMELEN                          = 0x100
+	NFT_OSF_MAXGENRELEN                         = 0x10
+	NFT_QUEUE_FLAG_BYPASS                       = 0x1
+	NFT_QUEUE_FLAG_CPU_FANOUT                   = 0x2
+	NFT_QUEUE_FLAG_MASK                         = 0x3
+	NFT_REG32_COUNT                             = 0x10
+	NFT_REG32_SIZE                              = 0x4
+	NFT_REG_MAX                                 = 0x4
+	NFT_REG_SIZE                                = 0x10
+	NFT_REJECT_ICMPX_MAX                        = 0x3
+	NFT_RT_MAX                                  = 0x4
+	NFT_SECMARK_CTX_MAXLEN                      = 0x100
+	NFT_SET_MAXNAMELEN                          = 0x100
+	NFT_SOCKET_MAX                              = 0x3
+	NFT_TABLE_F_MASK                            = 0x3
+	NFT_TABLE_MAXNAMELEN                        = 0x100
+	NFT_TRACETYPE_MAX                           = 0x3
+	NFT_TUNNEL_F_MASK                           = 0x7
+	NFT_TUNNEL_MAX                              = 0x1
+	NFT_TUNNEL_MODE_MAX                         = 0x2
+	NFT_USERDATA_MAXLEN                         = 0x100
+	NFT_XFRM_KEY_MAX                            = 0x6
+	NF_NAT_RANGE_MAP_IPS                        = 0x1
+	NF_NAT_RANGE_MASK                           = 0x7f
+	NF_NAT_RANGE_NETMAP                         = 0x40
+	NF_NAT_RANGE_PERSISTENT                     = 0x8
+	NF_NAT_RANGE_PROTO_OFFSET                   = 0x20
+	NF_NAT_RANGE_PROTO_RANDOM                   = 0x4
+	NF_NAT_RANGE_PROTO_RANDOM_ALL               = 0x14
+	NF_NAT_RANGE_PROTO_RANDOM_FULLY             = 0x10
+	NF_NAT_RANGE_PROTO_SPECIFIED                = 0x2
 	NILFS_SUPER_MAGIC                           = 0x3434
 	NL0                                         = 0x0
 	NL1                                         = 0x100

vendor/golang.org/x/sys/unix/zsyscall_openbsd_386.go

@@ -2297,5 +2297,3 @@ func unveil(path *byte, flags *byte) (err error) {
 var libc_unveil_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_unveil unveil "libc.so"
-
-

vendor/golang.org/x/sys/unix/zsyscall_openbsd_amd64.go

@@ -2297,5 +2297,3 @@ func unveil(path *byte, flags *byte) (err error) {
 var libc_unveil_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_unveil unveil "libc.so"
-
-

vendor/golang.org/x/sys/unix/zsyscall_openbsd_arm.go

@@ -2297,5 +2297,3 @@ func unveil(path *byte, flags *byte) (err error) {
 var libc_unveil_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_unveil unveil "libc.so"
-
-

vendor/golang.org/x/sys/unix/zsyscall_openbsd_arm64.go

@@ -2297,5 +2297,3 @@ func unveil(path *byte, flags *byte) (err error) {
 var libc_unveil_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_unveil unveil "libc.so"
-
-

vendor/golang.org/x/sys/unix/zsyscall_openbsd_mips64.go

@@ -2297,5 +2297,3 @@ func unveil(path *byte, flags *byte) (err error) {
 var libc_unveil_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_unveil unveil "libc.so"
-
-

vendor/golang.org/x/sys/unix/zsyscall_openbsd_ppc64.go

@@ -2297,5 +2297,3 @@ func unveil(path *byte, flags *byte) (err error) {
 var libc_unveil_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_unveil unveil "libc.so"
-
-

vendor/golang.org/x/sys/unix/zsyscall_openbsd_riscv64.go

@@ -2297,5 +2297,3 @@ func unveil(path *byte, flags *byte) (err error) {
 var libc_unveil_trampoline_addr uintptr
 
 //go:cgo_import_dynamic libc_unveil unveil "libc.so"
-
-

vendor/golang.org/x/sys/windows/syscall_windows.go

@@ -194,6 +194,7 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	GetComputerName(buf *uint16, n *uint32) (err error) = GetComputerNameW
 //sys	GetComputerNameEx(nametype uint32, buf *uint16, n *uint32) (err error) = GetComputerNameExW
 //sys	SetEndOfFile(handle Handle) (err error)
+//sys	SetFileValidData(handle Handle, validDataLength int64) (err error)
 //sys	GetSystemTimeAsFileTime(time *Filetime)
 //sys	GetSystemTimePreciseAsFileTime(time *Filetime)
 //sys	GetTimeZoneInformation(tzi *Timezoneinformation) (rc uint32, err error) [failretval==0xffffffff]

vendor/golang.org/x/sys/windows/zsyscall_windows.go

@@ -342,6 +342,7 @@ var (
 	procSetDefaultDllDirectories                             = modkernel32.NewProc("SetDefaultDllDirectories")
 	procSetDllDirectoryW                                     = modkernel32.NewProc("SetDllDirectoryW")
 	procSetEndOfFile                                         = modkernel32.NewProc("SetEndOfFile")
+	procSetFileValidData                                     = modkernel32.NewProc("SetFileValidData")
 	procSetEnvironmentVariableW                              = modkernel32.NewProc("SetEnvironmentVariableW")
 	procSetErrorMode                                         = modkernel32.NewProc("SetErrorMode")
 	procSetEvent                                             = modkernel32.NewProc("SetEvent")
@@ -2988,6 +2989,14 @@ func SetEndOfFile(handle Handle) (err error) {
 	return
 }
 
+func SetFileValidData(handle Handle, validDataLength int64) (err error) {
+	r1, _, e1 := syscall.Syscall(procSetFileValidData.Addr(), 2, uintptr(handle), uintptr(validDataLength), 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func SetEnvironmentVariable(name *uint16, value *uint16) (err error) {
 	r1, _, e1 := syscall.Syscall(procSetEnvironmentVariableW.Addr(), 2, uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(value)), 0)
 	if r1 == 0 {

vendor/modules.txt

@@ -467,7 +467,7 @@ go.opentelemetry.io/proto/otlp/common/v1
 go.opentelemetry.io/proto/otlp/metrics/v1
 go.opentelemetry.io/proto/otlp/resource/v1
 go.opentelemetry.io/proto/otlp/trace/v1
-# golang.org/x/crypto v0.17.0
+# golang.org/x/crypto v0.18.0
 ## explicit; go 1.18
 golang.org/x/crypto/acme
 golang.org/x/crypto/acme/autocert
@@ -483,11 +483,12 @@ golang.org/x/crypto/internal/poly1305
 golang.org/x/crypto/pbkdf2
 golang.org/x/crypto/pkcs12
 golang.org/x/crypto/pkcs12/internal/rc2
-# golang.org/x/net v0.18.0
+# golang.org/x/net v0.20.0
 ## explicit; go 1.18
 golang.org/x/net/context
 golang.org/x/net/http/httpguts
 golang.org/x/net/http2
+golang.org/x/net/http2/h2c
 golang.org/x/net/http2/hpack
 golang.org/x/net/idna
 golang.org/x/net/internal/timeseries
@@ -504,7 +505,7 @@ golang.org/x/oauth2/jwt
 # golang.org/x/sync v0.3.0
 ## explicit; go 1.17
 golang.org/x/sync/semaphore
-# golang.org/x/sys v0.15.0
+# golang.org/x/sys v0.16.0
 ## explicit; go 1.18
 golang.org/x/sys/cpu
 golang.org/x/sys/unix