portforward: tunnel spdy through websockets

Kubernetes-commit: 8b447d8c97e8823b4308eb91cf7d75693e867c61

tools/portforward/tunneling_dialer.go

@@ -0,0 +1,93 @@
+/*
+Copyright 2023 The Kubernetes 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 portforward
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"k8s.io/apimachinery/pkg/util/httpstream"
+	"k8s.io/apimachinery/pkg/util/httpstream/spdy"
+	constants "k8s.io/apimachinery/pkg/util/portforward"
+	restclient "k8s.io/client-go/rest"
+	"k8s.io/client-go/transport/websocket"
+	"k8s.io/klog/v2"
+)
+
+const PingPeriod = 10 * time.Second
+
+// tunnelingDialer implements "httpstream.Dial" interface
+type tunnelingDialer struct {
+	url       *url.URL
+	transport http.RoundTripper
+	holder    websocket.ConnectionHolder
+}
+
+// NewTunnelingDialer creates and returns the tunnelingDialer structure which implemements the "httpstream.Dialer"
+// interface. The dialer can upgrade a websocket request, creating a websocket connection. This function
+// returns an error if one occurs.
+func NewSPDYOverWebsocketDialer(url *url.URL, config *restclient.Config) (httpstream.Dialer, error) {
+	transport, holder, err := websocket.RoundTripperFor(config)
+	if err != nil {
+		return nil, err
+	}
+	return &tunnelingDialer{
+		url:       url,
+		transport: transport,
+		holder:    holder,
+	}, nil
+}
+
+// Dial upgrades to a tunneling streaming connection, returning a SPDY connection
+// containing a WebSockets connection (which implements "net.Conn"). Also
+// returns the protocol negotiated, or an error.
+func (d *tunnelingDialer) Dial(protocols ...string) (httpstream.Connection, string, error) {
+	// There is no passed context, so skip the context when creating request for now.
+	// Websockets requires "GET" method: RFC 6455 Sec. 4.1 (page 17).
+	req, err := http.NewRequest("GET", d.url.String(), nil)
+	if err != nil {
+		return nil, "", err
+	}
+	// Add the spdy tunneling prefix to the requested protocols. The tunneling
+	// handler will know how to negotiate these protocols.
+	tunnelingProtocols := []string{}
+	for _, protocol := range protocols {
+		tunnelingProtocol := constants.WebsocketsSPDYTunnelingPrefix + protocol
+		tunnelingProtocols = append(tunnelingProtocols, tunnelingProtocol)
+	}
+	klog.V(4).Infoln("Before WebSocket Upgrade Connection...")
+	conn, err := websocket.Negotiate(d.transport, d.holder, req, tunnelingProtocols...)
+	if err != nil {
+		return nil, "", err
+	}
+	if conn == nil {
+		return nil, "", fmt.Errorf("negotiated websocket connection is nil")
+	}
+	protocol := conn.Subprotocol()
+	protocol = strings.TrimPrefix(protocol, constants.WebsocketsSPDYTunnelingPrefix)
+	klog.V(4).Infof("negotiated protocol: %s", protocol)
+
+	// Wrap the websocket connection which implements "net.Conn".
+	tConn := NewTunnelingConnection("client", conn)
+	// Create SPDY connection injecting the previously created tunneling connection.
+	spdyConn, err := spdy.NewClientConnectionWithPings(tConn, PingPeriod)
+
+	return spdyConn, protocol, err
+}