dnsdist: Better handling of XSK frames without any data

This might happen when we are creating a frame from scratch.

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

diff --git a/pdns/dnsdistdist/xsk.cc b/pdns/dnsdistdist/xsk.cc
index 4411196594f74e02961bee459a717c9e97149542..6689335a28cb46a741b8464dc522cecff896b3c5 100644 (file)
--- a/pdns/dnsdistdist/xsk.cc
+++ b/pdns/dnsdistdist/xsk.cc
@@ -551,6 +551,10 @@ XskSocket::XskUmem::~XskUmem()
 
 [[nodiscard]] size_t XskPacket::getDataSize() const noexcept
 {
+  const auto dataOffset = getDataOffset();
+  if (frameLength < dataOffset) {
+    return 0U;
+  }
   return frameLength - getDataOffset();
 }