Apply origin request SNI selection

protocol/cloudflare/dispatch.go

@@ -231,7 +231,7 @@ func (i *Inbound) handleHTTPStream(ctx context.Context, stream io.ReadWriteClose
 	metadata.Network = N.NetworkTCP
 	i.logger.InfoContext(ctx, "inbound HTTP connection to ", metadata.Destination)
 
-	transport, cleanup := i.newRouterOriginTransport(ctx, metadata, service.OriginRequest)
+	transport, cleanup := i.newRouterOriginTransport(ctx, metadata, service.OriginRequest, request.MetadataMap()[metadataHTTPHost])
 	defer cleanup()
 	i.roundTripHTTP(ctx, stream, respWriter, request, service, transport)
 }
@@ -240,7 +240,7 @@ func (i *Inbound) handleWebSocketStream(ctx context.Context, stream io.ReadWrite
 	metadata.Network = N.NetworkTCP
 	i.logger.InfoContext(ctx, "inbound WebSocket connection to ", metadata.Destination)
 
-	transport, cleanup := i.newRouterOriginTransport(ctx, metadata, service.OriginRequest)
+	transport, cleanup := i.newRouterOriginTransport(ctx, metadata, service.OriginRequest, request.MetadataMap()[metadataHTTPHost])
 	defer cleanup()
 	i.roundTripHTTP(ctx, stream, respWriter, request, service, transport)
 }
@@ -249,7 +249,7 @@ func (i *Inbound) handleDirectHTTPStream(ctx context.Context, stream io.ReadWrit
 	metadata.Network = N.NetworkTCP
 	i.logger.InfoContext(ctx, "inbound HTTP connection to ", request.Dest)
 
-	transport, cleanup, err := i.newDirectOriginTransport(service)
+	transport, cleanup, err := i.newDirectOriginTransport(service, request.MetadataMap()[metadataHTTPHost])
 	if err != nil {
 		i.logger.ErrorContext(ctx, "build direct origin transport: ", err)
 		respWriter.WriteResponse(err, nil)
@@ -263,7 +263,7 @@ func (i *Inbound) handleDirectWebSocketStream(ctx context.Context, stream io.Rea
 	metadata.Network = N.NetworkTCP
 	i.logger.InfoContext(ctx, "inbound WebSocket connection to ", request.Dest)
 
-	transport, cleanup, err := i.newDirectOriginTransport(service)
+	transport, cleanup, err := i.newDirectOriginTransport(service, request.MetadataMap()[metadataHTTPHost])
 	if err != nil {
 		i.logger.ErrorContext(ctx, "build direct origin transport: ", err)
 		respWriter.WriteResponse(err, nil)
@@ -329,7 +329,7 @@ func (i *Inbound) roundTripHTTP(ctx context.Context, stream io.ReadWriteCloser,
 	}
 }
 
-func (i *Inbound) newRouterOriginTransport(ctx context.Context, metadata adapter.InboundContext, originRequest OriginRequestConfig) (*http.Transport, func()) {
+func (i *Inbound) newRouterOriginTransport(ctx context.Context, metadata adapter.InboundContext, originRequest OriginRequestConfig, requestHost string) (*http.Transport, func()) {
 	input, output := pipe.Pipe()
 	done := make(chan struct{})
 	go i.router.RouteConnectionEx(ctx, output, metadata, N.OnceClose(func(it error) {
@@ -344,7 +344,7 @@ func (i *Inbound) newRouterOriginTransport(ctx context.Context, metadata adapter
 		IdleConnTimeout:     originRequest.KeepAliveTimeout,
 		MaxIdleConns:        originRequest.KeepAliveConnections,
 		MaxIdleConnsPerHost: originRequest.KeepAliveConnections,
-		TLSClientConfig:     buildOriginTLSConfig(originRequest),
+		TLSClientConfig:     buildOriginTLSConfig(originRequest, requestHost),
 		DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
 			return input, nil
 		},
@@ -358,7 +358,7 @@ func (i *Inbound) newRouterOriginTransport(ctx context.Context, metadata adapter
 	}
 }
 
-func (i *Inbound) newDirectOriginTransport(service ResolvedService) (*http.Transport, func(), error) {
+func (i *Inbound) newDirectOriginTransport(service ResolvedService, requestHost string) (*http.Transport, func(), error) {
 	transport := &http.Transport{
 		DisableCompression:  true,
 		ForceAttemptHTTP2:   service.OriginRequest.HTTP2Origin,
@@ -366,7 +366,7 @@ func (i *Inbound) newDirectOriginTransport(service ResolvedService) (*http.Trans
 		IdleConnTimeout:     service.OriginRequest.KeepAliveTimeout,
 		MaxIdleConns:        service.OriginRequest.KeepAliveConnections,
 		MaxIdleConnsPerHost: service.OriginRequest.KeepAliveConnections,
-		TLSClientConfig:     buildOriginTLSConfig(service.OriginRequest),
+		TLSClientConfig:     buildOriginTLSConfig(service.OriginRequest, requestHost),
 	}
 	switch service.Kind {
 	case ResolvedServiceUnix, ResolvedServiceUnixTLS:
@@ -386,10 +386,10 @@ func (i *Inbound) newDirectOriginTransport(service ResolvedService) (*http.Trans
 	return transport, func() {}, nil
 }
 
-func buildOriginTLSConfig(originRequest OriginRequestConfig) *tls.Config {
+func buildOriginTLSConfig(originRequest OriginRequestConfig, requestHost string) *tls.Config {
 	tlsConfig := &tls.Config{
 		InsecureSkipVerify: originRequest.NoTLSVerify, //nolint:gosec
-		ServerName:         originRequest.OriginServerName,
+		ServerName:         originTLSServerName(originRequest, requestHost),
 	}
 	if originRequest.CAPool == "" {
 		return tlsConfig
@@ -405,6 +405,19 @@ func buildOriginTLSConfig(originRequest OriginRequestConfig) *tls.Config {
 	return tlsConfig
 }
 
+func originTLSServerName(originRequest OriginRequestConfig, requestHost string) string {
+	if originRequest.OriginServerName != "" {
+		return originRequest.OriginServerName
+	}
+	if !originRequest.MatchSNIToHost {
+		return ""
+	}
+	if host, _, err := net.SplitHostPort(requestHost); err == nil {
+		return host
+	}
+	return requestHost
+}
+
 func applyOriginRequest(request *http.Request, originRequest OriginRequestConfig) *http.Request {
 	request = request.Clone(request.Context())
 	if originRequest.HTTPHostHeader != "" {

protocol/cloudflare/origin_request_test.go

@@ -0,0 +1,33 @@
+//go:build with_cloudflare_tunnel
+
+package cloudflare
+
+import "testing"
+
+func TestOriginTLSServerName(t *testing.T) {
+	t.Run("origin server name overrides host", func(t *testing.T) {
+		serverName := originTLSServerName(OriginRequestConfig{
+			OriginServerName: "origin.example.com",
+			MatchSNIToHost:   true,
+		}, "request.example.com")
+		if serverName != "origin.example.com" {
+			t.Fatalf("expected origin.example.com, got %s", serverName)
+		}
+	})
+
+	t.Run("match sni to host strips port", func(t *testing.T) {
+		serverName := originTLSServerName(OriginRequestConfig{
+			MatchSNIToHost: true,
+		}, "request.example.com:443")
+		if serverName != "request.example.com" {
+			t.Fatalf("expected request.example.com, got %s", serverName)
+		}
+	})
+
+	t.Run("disabled match keeps empty server name", func(t *testing.T) {
+		serverName := originTLSServerName(OriginRequestConfig{}, "request.example.com")
+		if serverName != "" {
+			t.Fatalf("expected empty server name, got %s", serverName)
+		}
+	})
+}