From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Thu, 10 Oct 2019 15:44:43 +0000 (+0200)
Subject: dnsdist: Advertise the size really available in the query buffer
X-Git-Tag: dnsdist-1.4.0-rc4~22^2~4
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=be7dec02ae8bbb6fac253240691668c4ab86d140;p=pdns

dnsdist: Advertise the size really available in the query buffer

We use to advertise s_udpIncomingBufferSize (1500) but the buffer
is really 4096 bytes long. This allows much larger responses from
to be returned from the cache.
---

diff --git a/pdns/dnsdist.cc b/pdns/dnsdist.cc
index ba9760548..177cd4493 100644
--- a/pdns/dnsdist.cc
+++ b/pdns/dnsdist.cc
@@ -1787,7 +1787,7 @@ try
     ComboAddress remote;
     ComboAddress dest;
     remote.sin4.sin_family = cs->local.sin4.sin_family;
-    fillMSGHdr(&msgh, &iov, &cbuf, sizeof(cbuf), packet, sizeof(packet), &remote);
+    fillMSGHdr(&msgh, &iov, &cbuf, sizeof(cbuf), packet, s_udpIncomingBufferSize, &remote);
 
     for(;;) {
       ssize_t got = recvmsg(cs->udpFD, &msgh, 0);
@@ -1797,7 +1797,7 @@ try
         continue;
       }
 
-      processUDPQuery(*cs, holders, &msgh, remote, dest, packet, static_cast<uint16_t>(got), s_udpIncomingBufferSize, nullptr, nullptr, nullptr, nullptr);
+      processUDPQuery(*cs, holders, &msgh, remote, dest, packet, static_cast<uint16_t>(got), sizeof(packet), nullptr, nullptr, nullptr, nullptr);
     }
   }
 }