package service import ( "crypto/tls" "net" "net/http" "time" "github.com/traefik/traefik/v2/pkg/config/dynamic" "golang.org/x/net/http/httpguts" "golang.org/x/net/http2" ) func newSmartRoundTripper(transport *http.Transport, forwardingTimeouts *dynamic.ForwardingTimeouts) (http.RoundTripper, error) { transportHTTP1 := transport.Clone() transportHTTP2, err := http2.ConfigureTransports(transport) if err != nil { return nil, err } if forwardingTimeouts != nil { transportHTTP2.ReadIdleTimeout = time.Duration(forwardingTimeouts.ReadIdleTimeout) transportHTTP2.PingTimeout = time.Duration(forwardingTimeouts.PingTimeout) } transportH2C := &h2cTransportWrapper{ Transport: &http2.Transport{ DialTLS: func(network, addr string, cfg *tls.Config) (net.Conn, error) { return net.Dial(network, addr) }, AllowHTTP: true, }, } if forwardingTimeouts != nil { transportH2C.ReadIdleTimeout = time.Duration(forwardingTimeouts.ReadIdleTimeout) transportH2C.PingTimeout = time.Duration(forwardingTimeouts.PingTimeout) } transport.RegisterProtocol("h2c", transportH2C) return &smartRoundTripper{ http2: transport, http: transportHTTP1, }, nil } // smartRoundTripper implements RoundTrip while making sure that HTTP/2 is not used // with protocols that start with a Connection Upgrade, such as SPDY or Websocket. type smartRoundTripper struct { http2 *http.Transport http *http.Transport } func (m *smartRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) { // If we have a connection upgrade, we don't use HTTP/2 if httpguts.HeaderValuesContainsToken(req.Header["Connection"], "Upgrade") { return m.http.RoundTrip(req) } return m.http2.RoundTrip(req) }