From d47fad8a9b62e792f6e12ffd1d03e175bb255292 Mon Sep 17 00:00:00 2001
From: Artem Glazychev <artem.glazychev@xored.com>
Date: Wed, 31 Aug 2022 12:24:11 +0700
Subject: [PATCH] Handle empty dns answer

Signed-off-by: Artem Glazychev <artem.glazychev@xored.com>
---
 pkg/tools/dnsutils/cache/handler.go  | 3 +++
 pkg/tools/dnsutils/fanout/handler.go | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/pkg/tools/dnsutils/cache/handler.go b/pkg/tools/dnsutils/cache/handler.go
index da1032b7b..1bbc7ea03 100644
--- a/pkg/tools/dnsutils/cache/handler.go
+++ b/pkg/tools/dnsutils/cache/handler.go
@@ -85,6 +85,9 @@ func (h *dnsCacheHandler) updateTTL() {
 }
 
 func validateMsg(m *dns.Msg) bool {
+	if len(m.Answer) == 0 {
+		return false
+	}
 	for _, answer := range m.Answer {
 		if answer.Header().Ttl <= 0 {
 			return false
diff --git a/pkg/tools/dnsutils/fanout/handler.go b/pkg/tools/dnsutils/fanout/handler.go
index 10dc550fe..7d2d9e14e 100644
--- a/pkg/tools/dnsutils/fanout/handler.go
+++ b/pkg/tools/dnsutils/fanout/handler.go
@@ -102,7 +102,7 @@ func (h *fanoutHandler) waitResponse(ctx context.Context, respCh <-chan *dns.Msg
 				}
 				continue
 			}
-			if resp.Rcode == dns.RcodeSuccess {
+			if resp.Rcode == dns.RcodeSuccess && len(resp.Answer) != 0 {
 				return resp
 			}
 			if respCount == 0 {