From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Fri, 3 May 2024 12:28:12 +0000 (+0200)
Subject: dnsdist: Reply to HTTP/2 PING frames immediately
X-Git-Tag: dnsdist-1.9.5~16^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F14163%2Fhead;p=thirdparty%2Fpdns.git

dnsdist: Reply to HTTP/2 PING frames immediately

We usually buffer a bit to avoid sending a lot of small data chunks
on the wire (or to the kernel anyway), but for `HTTP/2 PING` frames
that are not followed by anything else calling for a response, this
causes an issue as these frames are designed to measure the latency
between a client and a server, and are used by HTTP/2 proxies to
ensure that a connection can be reused.

(cherry picked from commit 4170083b33b171b150257311ef832c743f4d32c6)
---

diff --git a/pdns/dnsdistdist/dnsdist-nghttp2-in.cc b/pdns/dnsdistdist/dnsdist-nghttp2-in.cc
index e40f5e64b1..a016363c6f 100644
--- a/pdns/dnsdistdist/dnsdist-nghttp2-in.cc
+++ b/pdns/dnsdistdist/dnsdist-nghttp2-in.cc
@@ -922,6 +922,9 @@ int IncomingHTTP2Connection::on_frame_recv_callback(nghttp2_session* session, co
       return NGHTTP2_ERR_CALLBACK_FAILURE;
     }
   }
+  else if (frame->hd.type == NGHTTP2_PING) {
+    conn->d_needFlush = true;
+  }
 
   return 0;
 }