From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Fri, 15 May 2026 13:59:15 +0000 (+0200)
Subject: dnsdist: Prevent duplicated responses for "too large" XSK responses
X-Git-Tag: auth-5.1.0~59^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d2f936aaddc2cb8b4b52e467d260a8d312ade92;p=thirdparty%2Fpdns.git

dnsdist: Prevent duplicated responses for "too large" XSK responses

Signed-off-by: Remi Gacogne <remi.gacogne@powerdns.com>
---

diff --git a/pdns/dnsdistdist/dnsdist-xsk.cc b/pdns/dnsdistdist/dnsdist-xsk.cc
index d66b5dea22..143f457587 100644
--- a/pdns/dnsdistdist/dnsdist-xsk.cc
+++ b/pdns/dnsdistdist/dnsdist-xsk.cc
@@ -70,6 +70,8 @@ void XskResponderThread(std::shared_ptr<DownstreamState> dss, std::shared_ptr<Xs
           auto response = packet.clonePacketBuffer();
           if (response.size() > packet.getCapacity()) {
             /* fallback to sending the packet via normal socket */
+            VERBOSESLOG(infolog("XSK packet falling back because packet is too large"),
+                        logger->info(Logr::Info, "XSK packet falling back because packet is too large"));
             ids->xskPacketHeader.clear();
           }
           if (!processResponderPacket(dss, response, std::move(*ids))) {
@@ -79,10 +81,6 @@ void XskResponderThread(std::shared_ptr<DownstreamState> dss, std::shared_ptr<Xs
             return;
           }
           if (response.size() > packet.getCapacity()) {
-            /* fallback to sending the packet via normal socket */
-            sendUDPResponse(ids->cs->udpFD, response, ids->delayMsec, ids->hopLocal, ids->hopRemote);
-            VERBOSESLOG(infolog("XSK packet falling back because packet is too large"),
-                        logger->info(Logr::Info, "XSK packet falling back because packet is too large"));
             xskInfo->markAsFree(packet);
             return;
           }