[client] Support disable search domain for custom zones (#4826)

Two new boolean flags, SearchDomainDisabled and SkipPTRProcess, are added to CustomZone and its protobuf; they are propagated through the engine to DNS host logic. Host matching now uses SearchDomainDisabled directly, and PTR collection skips zones with SkipPTRProcess; reverse zones are initialized with SearchDomainDisabled: true.

client/internal/dns.go

@@ -76,6 +76,9 @@ func collectPTRRecords(config *nbdns.Config, prefix netip.Prefix) []nbdns.Simple
 	var records []nbdns.SimpleRecord
 
 	for _, zone := range config.CustomZones {
+		if zone.SkipPTRProcess {
+			continue
+		}
 		for _, record := range zone.Records {
 			if record.Type != int(dns.TypeA) {
 				continue
@@ -106,8 +109,9 @@ func addReverseZone(config *nbdns.Config, network netip.Prefix) {
 	records := collectPTRRecords(config, network)
 
 	reverseZone := nbdns.CustomZone{
-		Domain:  zoneName,
-		Records: records,
+		Domain:               zoneName,
+		Records:              records,
+		SearchDomainDisabled: true,
 	}
 
 	config.CustomZones = append(config.CustomZones, reverseZone)

client/internal/dns/host.go

@@ -11,11 +11,6 @@ import (
 	nbdns "github.com/netbirdio/netbird/dns"
 )
 
-const (
-	ipv4ReverseZone = ".in-addr.arpa."
-	ipv6ReverseZone = ".ip6.arpa."
-)
-
 type hostManager interface {
 	applyDNSConfig(config HostDNSConfig, stateManager *statemanager.Manager) error
 	restoreHostDNS() error
@@ -110,10 +105,9 @@ func dnsConfigToHostDNSConfig(dnsConfig nbdns.Config, ip netip.Addr, port int) H
 	}
 
 	for _, customZone := range dnsConfig.CustomZones {
-		matchOnly := strings.HasSuffix(customZone.Domain, ipv4ReverseZone) || strings.HasSuffix(customZone.Domain, ipv6ReverseZone)
 		config.Domains = append(config.Domains, DomainConfig{
 			Domain:    strings.ToLower(dns.Fqdn(customZone.Domain)),
-			MatchOnly: matchOnly,
+			MatchOnly: customZone.SearchDomainDisabled,
 		})
 	}
 

client/internal/engine.go

@@ -1207,7 +1207,9 @@ func toDNSConfig(protoDNSConfig *mgmProto.DNSConfig, network netip.Prefix) nbdns
 
 	for _, zone := range protoDNSConfig.GetCustomZones() {
 		dnsZone := nbdns.CustomZone{
-			Domain: zone.GetDomain(),
+			Domain:               zone.GetDomain(),
+			SearchDomainDisabled: zone.GetSearchDomainDisabled(),
+			SkipPTRProcess:       zone.GetSkipPTRProcess(),
 		}
 		for _, record := range zone.Records {
 			dnsRecord := nbdns.SimpleRecord{