DoH: reject non-h2 early

Previously, non-h2 connections would be accepted, and then error out
with a verbose message "http2: session_recv from ____ failed,
error: Received bad client magic byte string". Instead, we can detect
absence of h2 support at connection time and reject with a clearer
verbose message.

diff --git a/util/netevent.c b/util/netevent.c
index 141e48d48b3f66aa88a370a6925f9f42095b19d0..d517ae544ed1d558312c487abb852240d804bde9 100644 (file)
--- a/util/netevent.c
+++ b/util/netevent.c
@@ -1748,6 +1748,9 @@ ssl_handshake(struct comm_point* c)
                        /* connection upgraded to HTTP2 */
                        c->tcp_do_toggle_rw = 0;
                        c->use_h2 = 1;
+               } else {
+                       verbose(VERB_ALGO, "client doesn't support HTTP/2");
+                       return 0;
                }
        }
 #endif