websocket: set the HTTP host header in WSS

* Send host header

Co-authored-by: Thibault Meunier <thibault@cloudflare.com>

* Add comment and use splithostport

* Return error

* Defer the close

Co-authored-by: Thibault Meunier <thibault@cloudflare.com>

p2p/transport/websocket/addrs.go

@@ -132,7 +132,7 @@ func parseMultiaddr(maddr ma.Multiaddr) (*url.URL, error) {
 
 type parsedWebsocketMultiaddr struct {
 	isWSS bool
-	// sni is the SNI value for the TLS handshake
+	// sni is the SNI value for the TLS handshake, and for setting HTTP Host header
 	sni *ma.Component
 	// the rest of the multiaddr before the /tls/sni/example.com/ws or /ws or /wss
 	restMultiaddr ma.Multiaddr

p2p/transport/websocket/websocket.go

@@ -4,6 +4,7 @@ package websocket
 import (
 	"context"
 	"crypto/tls"
+	"net"
 	"net/http"
 	"time"
 
@@ -186,6 +187,17 @@ func (t *WebsocketTransport) maDial(ctx context.Context, raddr ma.Multiaddr) (ma
 			copytlsClientConf := t.tlsClientConf.Clone()
 			copytlsClientConf.ServerName = sni
 			dialer.TLSClientConfig = copytlsClientConf
+			ipAddr := wsurl.Host
+			// Setting the NetDial because we already have the resolved IP address, so we don't want to do another resolution.
+			// We set the `.Host` to the sni field so that the host header gets properly set.
+			dialer.NetDial = func(network, address string) (net.Conn, error) {
+				tcpAddr, err := net.ResolveTCPAddr(network, ipAddr)
+				if err != nil {
+					return nil, err
+				}
+				return net.DialTCP("tcp", nil, tcpAddr)
+			}
+			wsurl.Host = sni + ":" + wsurl.Port()
 		} else {
 			dialer.TLSClientConfig = t.tlsClientConf
 		}

p2p/transport/websocket/websocket_test.go

@@ -9,10 +9,13 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
+	"errors"
 	"fmt"
 	"io"
 	"math/big"
 	"net"
+	"net/http"
+	"strings"
 	"testing"
 	"time"
 
@@ -218,6 +221,44 @@ func getTLSConf(t *testing.T, ip net.IP, start, end time.Time) *tls.Config {
 	}
 }
 
+func TestHostHeaderWss(t *testing.T) {
+	server := &http.Server{}
+	l, err := net.Listen("tcp", ":0")
+	require.NoError(t, err)
+	defer server.Close()
+
+	errChan := make(chan error, 1)
+	go func() {
+		server.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			defer close(errChan)
+			if !strings.Contains(r.Host, "example.com") {
+				errChan <- errors.New("Didn't see host header")
+			}
+			w.WriteHeader(http.StatusNotFound)
+		})
+		server.TLSConfig = getTLSConf(t, net.ParseIP("127.0.0.1"), time.Now(), time.Now().Add(time.Hour))
+		server.ServeTLS(l, "", "")
+	}()
+
+	_, port, err := net.SplitHostPort(l.Addr().String())
+	require.NoError(t, err)
+	serverMA := ma.StringCast("/ip4/127.0.0.1/tcp/" + port + "/tls/sni/example.com/ws")
+
+	tlsConfig := &tls.Config{InsecureSkipVerify: true} // Our test server doesn't have a cert signed by a CA
+	_, u := newSecureUpgrader(t)
+	tpt, err := New(u, network.NullResourceManager, WithTLSClientConfig(tlsConfig))
+	require.NoError(t, err)
+
+	masToDial, err := tpt.Resolve(context.Background(), serverMA)
+	require.NoError(t, err)
+
+	_, err = tpt.Dial(context.Background(), masToDial[0], test.RandPeerIDFatal(t))
+	require.Error(t, err)
+
+	err = <-errChan
+	require.NoError(t, err)
+}
+
 func TestDialWss(t *testing.T) {
 	serverMA, rid, errChan := testWSSServer(t, ma.StringCast("/ip4/127.0.0.1/tcp/0/tls/sni/example.com/ws"))
 	require.Contains(t, serverMA.String(), "tls")