From 284f10b296eb5cb64ea9dc81fd10371e055e0bd0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Tue, 22 Apr 2025 23:08:24 +0800
Subject: [PATCH] Fix DNS Lookup

---
 dns/client.go | 9 ++++++---
 dns/router.go | 3 +--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/dns/client.go b/dns/client.go
index f456f878..2cf75da6 100644
--- a/dns/client.go
+++ b/dns/client.go
@@ -268,10 +268,13 @@ func (c *Client) Lookup(ctx context.Context, transport adapter.DNSTransport, dom
 		return nil
 	})
 	err := group.Run(ctx)
-	if len(response4) == 0 && len(response6) == 0 {
+	if len(response4) > 0 || len(response6) > 0 {
+		return sortAddresses(response4, response6, options.Strategy), nil
+	} else if err != nil {
 		return nil, err
+	} else {
+		return nil, RcodeError(dns.RcodeNameError)
 	}
-	return sortAddresses(response4, response6, options.Strategy), nil
 }
 
 func (c *Client) ClearCache() {
@@ -483,7 +486,7 @@ func (c *Client) loadResponse(question dns.Question, transport adapter.DNSTransp
 }
 
 func MessageToAddresses(response *dns.Msg) ([]netip.Addr, error) {
-	if response.Rcode != dns.RcodeSuccess && response.Rcode != dns.RcodeNameError {
+	if response.Rcode != dns.RcodeSuccess {
 		return nil, RcodeError(response.Rcode)
 	}
 	addresses := make([]netip.Addr, 0, len(response.Answer))
diff --git a/dns/router.go b/dns/router.go
index 44edadbd..dbfdcfb8 100644
--- a/dns/router.go
+++ b/dns/router.go
@@ -332,8 +332,7 @@ func (r *Router) Lookup(ctx context.Context, domain string, options adapter.DNSQ
 				r.logger.ErrorContext(ctx, E.Cause(err, "lookup failed for ", domain))
 			}
 		} else if len(responseAddrs) == 0 {
-			r.logger.ErrorContext(ctx, "lookup failed for ", domain, ": empty result")
-			err = RcodeNameError
+			panic("unexpected empty result")
 		}
 	}
 	responseAddrs, cached = r.client.LookupCache(domain, options.Strategy)