From fe1f02240037e92e9b813352648beb4e0dcdf625 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Sat, 25 Jul 2026 08:14:59 +0800
Subject: [PATCH] dns: Fix search domain expansion

DHCP option 119/15 and resolved link domains are not rooted, so appending
them to the query name produced a non-FQDN name, failing to pack with
"domain must be fully qualified".
---
 dns/transport/dhcp/dhcp.go  | 9 +++++++--
 service/resolved/service.go | 6 ++++--
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/dns/transport/dhcp/dhcp.go b/dns/transport/dhcp/dhcp.go
index 688f4eef5..3abc7cf53 100644
--- a/dns/transport/dhcp/dhcp.go
+++ b/dns/transport/dhcp/dhcp.go
@@ -397,9 +397,14 @@ func (t *Transport) fetchServersResponse(iface *control.Interface, packetConn ne
 func (t *Transport) recreateServers(iface *control.Interface, dhcpPacket *dhcpv4.DHCPv4) error {
 	searchList := dhcpPacket.DomainSearch()
 	if searchList != nil && len(searchList.Labels) > 0 {
-		t.search = searchList.Labels
+		t.search = common.Filter(common.Map(searchList.Labels, mDNS.Fqdn), func(it string) bool {
+			return it != "."
+		})
 	} else if dhcpPacket.DomainName() != "" {
-		t.search = []string{dhcpPacket.DomainName()}
+		domainName := mDNS.Fqdn(dhcpPacket.DomainName())
+		if domainName != "." {
+			t.search = []string{domainName}
+		}
 	}
 	serverAddrs := common.Map(dhcpPacket.DNS(), func(it net.IP) M.Socksaddr {
 		return M.SocksaddrFrom(M.AddrFromIP(it), 53)
diff --git a/service/resolved/service.go b/service/resolved/service.go
index 8f9740a06..d14082d7e 100644
--- a/service/resolved/service.go
+++ b/service/resolved/service.go
@@ -204,10 +204,12 @@ func (i *Service) onNetworkUpdate() {
 }
 
 func (conf *TransportLink) nameList(ndots int, name string) []string {
-	search := common.Map(common.Filter(conf.domain, func(it LinkDomain) bool {
+	search := common.Filter(common.Map(common.Filter(conf.domain, func(it LinkDomain) bool {
 		return !it.RoutingOnly
 	}), func(it LinkDomain) string {
-		return it.Domain
+		return mDNS.Fqdn(it.Domain)
+	}), func(it string) bool {
+		return it != "."
 	})
 
 	l := len(name)