Commit b5901cab authored May 08, 2019 by Jay Satiro

http: Ignore HTTP/2 prior knowledge setting for HTTP proxies

- Do not switch to HTTP/2 for an HTTP proxy that is not tunnelling to
  the destination host.

We already do something similar for HTTPS proxies by not sending h2. [1]

Prior to this change setting CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE would
incorrectly use HTTP/2 to talk to the proxy, which is not something we
support (yet?). Also it's debatable whether or not that setting should
apply to HTTP/2 proxies.

[1]: https://github.com/curl/curl/commit/17c5d05

Bug: https://github.com/curl/curl/issues/3570
Bug: https://github.com/curl/curl/issues/3832

Closes https://github.com/curl/curl/pull/3853

parent 21d070a0

lib/http.c

+7 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1970,6 +1970,13 @@ CURLcode Curl_http(struct connectdata conn, bool done)
	#ifdef USE_NGHTTP2		#ifdef USE_NGHTTP2
	if(conn->data->set.httpversion ==		if(conn->data->set.httpversion ==
	CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE) {		CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE) {
			if(conn->bits.httpproxy && !conn->bits.tunnel_proxy) {
			/* We don't support HTTP/2 proxies yet. Also it's debatable whether
			or not this setting should apply to HTTP/2 proxies. */
			infof(data, "Ignoring HTTP/2 prior knowledge due to proxy\n");
			break;
			}

	DEBUGF(infof(data, "HTTP/2 over clean TCP\n"));		DEBUGF(infof(data, "HTTP/2 over clean TCP\n"));
	conn->httpversion = 20;		conn->httpversion = 20;