[wip] make use of new go1.24 so we don't need x/net/h2c package

go.mod

@@ -33,7 +33,6 @@ require (
 	go.opentelemetry.io/otel/trace v1.38.0
 	go.uber.org/automaxprocs v1.6.0
 	go.uber.org/zap v1.27.1
-	golang.org/x/net v0.47.0
 	golang.org/x/sync v0.18.0
 	golang.org/x/tools v0.39.0
 	gomodules.xyz/jsonpatch/v2 v2.5.0
@@ -89,6 +88,7 @@ require (
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/exp v0.0.0-20250210185358-939b2ce775ac // indirect
 	golang.org/x/mod v0.30.0 // indirect
+	golang.org/x/net v0.47.0 // indirect
 	golang.org/x/oauth2 v0.30.0 // indirect
 	golang.org/x/sys v0.38.0 // indirect
 	golang.org/x/term v0.37.0 // indirect

network/server.go

@@ -0,0 +1,38 @@
+/*
+Copyright 2025 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package network
+
+import (
+	"net/http"
+	"time"
+)
+
+func NewServer(addr string, h http.Handler) *http.Server {
+	var protocols http.Protocols
+	protocols.SetHTTP1(true)
+	protocols.SetHTTP2(true)
+	protocols.SetUnencryptedHTTP2(true)
+
+	return &http.Server{
+		Addr:      addr,
+		Handler:   h,
+		Protocols: &protocols,
+
+		// https://medium.com/a-journey-with-go/go-understand-and-mitigate-slowloris-attack-711c1b1403f6
+		ReadHeaderTimeout: time.Minute,
+	}
+}

network/transports.go

@@ -117,61 +117,120 @@ func dialBackOffHelper(ctx context.Context, network, address string, bo wait.Bac
 	return nil, fmt.Errorf("%w %s after %.2fs", ErrTimeoutDialing, address, elapsed.Seconds())
 }
 
-func newHTTPTransport(disableKeepAlives, disableCompression bool, maxIdle, maxIdlePerHost int) http.RoundTripper {
+func newHTTPTransport(
+	disableKeepAlives,
+	disableCompression bool,
+	maxIdle,
+	maxIdlePerHost int,
+) *http.Transport {
+	var protocols http.Protocols
+	protocols.SetHTTP1(true)
+
 	transport := http.DefaultTransport.(*http.Transport).Clone()
 	transport.DialContext = DialWithBackOff
 	transport.DisableKeepAlives = disableKeepAlives
 	transport.MaxIdleConns = maxIdle
 	transport.MaxIdleConnsPerHost = maxIdlePerHost
 	transport.ForceAttemptHTTP2 = false
 	transport.DisableCompression = disableCompression
+	transport.Protocols = &protocols
+
 	return transport
 }
 
 type DialTLSContextFunc func(ctx context.Context, network, addr string) (net.Conn, error)
 
-func newHTTPSTransport(disableKeepAlives, disableCompression bool, maxIdle, maxIdlePerHost int, tlsContext DialTLSContextFunc) http.RoundTripper {
+func newHTTPSTransport(
+	disableKeepAlives,
+	disableCompression bool,
+	maxIdle,
+	maxIdlePerHost int,
+	tlsContext DialTLSContextFunc,
+) *http.Transport {
+	var protocols http.Protocols
+	protocols.SetHTTP1(true)
+
 	transport := http.DefaultTransport.(*http.Transport).Clone()
 	transport.DisableKeepAlives = disableKeepAlives
 	transport.MaxIdleConns = maxIdle
 	transport.MaxIdleConnsPerHost = maxIdlePerHost
 	transport.ForceAttemptHTTP2 = false
 	transport.DisableCompression = disableCompression
 	transport.DialTLSContext = tlsContext
+	transport.Protocols = &protocols
 
 	return transport
 }
 
 // NewProberTransport creates a RoundTripper that is useful for probing,
 // since it will not cache connections.
 func NewProberTransport() http.RoundTripper {
-	return newAutoTransport(
-		newHTTPTransport(true /*disable keep-alives*/, false /*disable auto-compression*/, 0, 0 /*no caching*/),
-		NewH2CTransport())
+	http := newHTTPTransport(
+		true,  /*disable keep-alives*/
+		false, /*disable auto-compression*/
+		0,     /*max idle*/
+		0,     /*no caching*/
+	)
+
+	// h2 prior knowledge
+	h2 := http.Clone()
+	h2.Protocols.SetHTTP1(false)
+	h2.Protocols.SetUnencryptedHTTP2(true)
+
+	return newAutoTransport(http, h2)
 }
 
 // NewProxyAutoTLSTransport is same with NewProxyAutoTransport but it has DialTLSContextFunc to create HTTPS request.
 func NewProxyAutoTLSTransport(maxIdle, maxIdlePerHost int, tlsContext DialTLSContextFunc) http.RoundTripper {
-	return newAutoTransport(
-		newHTTPSTransport(false /*disable keep-alives*/, true /*disable auto-compression*/, maxIdle, maxIdlePerHost, tlsContext),
-		newH2Transport(true /*disable auto-compression*/, tlsContext))
+	https := newHTTPSTransport(
+		false, /*disable keep-alives*/
+		true,  /*disable auto-compression*/
+		maxIdle,
+		maxIdlePerHost,
+		tlsContext,
+	)
+
+	h2 := https.Clone()
+	h2.Protocols.SetHTTP1(false)
+	h2.Protocols.SetHTTP2(true)
+	h2.Protocols.SetUnencryptedHTTP2(true)
+
+	return newAutoTransport(https, h2)
 }
 
 // NewAutoTransport creates a RoundTripper that can use appropriate transport
 // based on the request's HTTP version.
 func NewAutoTransport(maxIdle, maxIdlePerHost int) http.RoundTripper {
-	return newAutoTransport(
-		newHTTPTransport(false /*disable keep-alives*/, false /*disable auto-compression*/, maxIdle, maxIdlePerHost),
-		newH2CTransport(false /*disable auto-compression*/))
+	http := newHTTPTransport(
+		false, /*disable keep-alives*/
+		false, /*disable auto-compression*/
+		maxIdle,
+		maxIdlePerHost,
+	)
+
+	h2 := http.Clone()
+	h2.Protocols.SetHTTP1(false)
+	h2.Protocols.SetUnencryptedHTTP2(true)
+
+	return newAutoTransport(http, h2)
 }
 
 // NewProxyAutoTransport creates a RoundTripper suitable for use by a reverse
 // proxy.  The returned transport uses HTTP or H2C based on the request's HTTP
 // version. The transport has DisableCompression set to true.
 func NewProxyAutoTransport(maxIdle, maxIdlePerHost int) http.RoundTripper {
-	return newAutoTransport(
-		newHTTPTransport(false /*disable keep-alives*/, true /*disable auto-compression*/, maxIdle, maxIdlePerHost),
-		newH2CTransport(true /*disable auto-compression*/))
+	http := newHTTPTransport(
+		false, /*disable keep-alives*/
+		true,  /*disable auto-compression*/
+		maxIdle,
+		maxIdlePerHost,
+	)
+
+	h2 := http.Clone()
+	h2.Protocols.SetHTTP1(false)
+	h2.Protocols.SetUnencryptedHTTP2(true)
+
+	return newAutoTransport(http, h2)
 }
 
 // AutoTransport uses h2c for HTTP2 requests and falls back to `http.DefaultTransport` for all others