commit 52bc759ac35ade721c87f53ba2d341a68c715c32 Author: David Fifield <david@bamsoftware.com> Date: Thu Jan 31 00:22:11 2019 -0700 utls: copy default timeouts etc. when using HTTP/1. Unfortunately I don't know a way to do the same for HTTP/2. Configuring an http.Transport and then calling http2.ConfigureTransport on it doesn't work; it leads to the same problem of an HTTP/1 client speaking to an HTTP/2 server. --- meek-client/utls.go | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/meek-client/utls.go b/meek-client/utls.go index 9076549..2c9c52e 100644 --- a/meek-client/utls.go +++ b/meek-client/utls.go @@ -39,6 +39,7 @@ import ( "net" "net/http" "net/url" + "reflect" "strings" "sync" @@ -46,6 +47,25 @@ import ( "golang.org/x/net/http2" ) +// Copy the public fields (fields for which CanSet is true) from src to dst. +// src and dst must be pointers to the same type. We use this to make copies of +// httpRoundTripper. We cannot use struct assignment, because http.Transport +// contains private mutexes. The idea of using reflection to copy only the +// public fields comes from a post by Nick Craig-Wood: +// https://groups.google.com/d/msg/Golang-Nuts/SDiGYNVE8iY/89hRKTF4BAAJ +func copyPublicFields(dst, src interface{}) { + if reflect.TypeOf(dst) != reflect.TypeOf(src) { + panic("unequal types") + } + dstValue := reflect.ValueOf(dst).Elem() + srcValue := reflect.ValueOf(src).Elem() + for i := 0; i < dstValue.NumField(); i++ { + if dstValue.Field(i).CanSet() { + dstValue.Field(i).Set(srcValue.Field(i)) + } + } +} + // Extract a host:port address from a URL, suitable for passing to net.Dial. func addrForDial(url *url.URL) (string, error) { host := url.Hostname() @@ -164,6 +184,10 @@ func makeRoundTripper(req *http.Request, clientHelloID *utls.ClientHelloID) (htt // Construct an http.Transport or http2.Transport depending on ALPN. switch protocol { case http2.NextProtoTLS: + // Unfortunately http2.Transport does not expose the same + // configuration options as http.Transport with regard to + // timeouts, etc., so we are at the mercy of the defaults. + // https://github.com/golang/go/issues/16581 return &http2.Transport{ DialTLS: func(network, addr string, _ *tls.Config) (net.Conn, error) { // Ignore the *tls.Config parameter; use our @@ -172,8 +196,13 @@ func makeRoundTripper(req *http.Request, clientHelloID *utls.ClientHelloID) (htt }, }, nil default: - // TODO: copy public fields from httpRoundTripper? - return &http.Transport{DialTLS: dialTLS}, nil + // With http.Transport, copy important default fields from + // http.DefaultTransport, such as TLSHandshakeTimeout and + // IdleConnTimeout. + tr := &http.Transport{} + copyPublicFields(tr, httpRoundTripper) + tr.DialTLS = dialTLS + return tr, nil } }