From 1046345e9da421ab2c0aa50e35a6b81b0aae646d Mon Sep 17 00:00:00 2001
From: PuerNya <safarier@outlook.com>
Date: Mon, 5 Feb 2024 02:42:15 +0800
Subject: [PATCH] Always disable cache for fake-ip DNS transport if
 `independent_cache` disabled

---
 route/router.go     |  2 ++
 route/router_dns.go | 32 +++++++++++++++++++-------------
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/route/router.go b/route/router.go
index e9807bd4..5e00d2c9 100644
--- a/route/router.go
+++ b/route/router.go
@@ -69,6 +69,7 @@ type Router struct {
 	geositeCache                       map[string]adapter.Rule
 	needFindProcess                    bool
 	dnsClient                          *dns.Client
+	dnsIndependentCache                bool
 	defaultDomainStrategy              dns.DomainStrategy
 	dnsRules                           []adapter.DNSRule
 	ruleSets                           []adapter.RuleSet
@@ -122,6 +123,7 @@ func NewRouter(
 		geositeOptions:        common.PtrValueOrDefault(options.Geosite),
 		geositeCache:          make(map[string]adapter.Rule),
 		needFindProcess:       hasRule(options.Rules, isProcessRule) || hasDNSRule(dnsOptions.Rules, isProcessDNSRule) || options.FindProcess,
+		dnsIndependentCache:   dnsOptions.IndependentCache,
 		defaultDetour:         options.Final,
 		defaultDomainStrategy: dns.DomainStrategy(dnsOptions.Strategy),
 		interfaceFinder:       control.NewDefaultInterfaceFinder(),
diff --git a/route/router_dns.go b/route/router_dns.go
index 21beca97..2ac439d7 100644
--- a/route/router_dns.go
+++ b/route/router_dns.go
@@ -56,7 +56,8 @@ func (r *Router) matchDNS(ctx context.Context, allowFakeIP bool, index int) (con
 					r.dnsLogger.ErrorContext(ctx, "transport not found: ", detour)
 					continue
 				}
-				if _, isFakeIP := transport.(adapter.FakeIPTransport); isFakeIP && !allowFakeIP {
+				_, isFakeIP := transport.(adapter.FakeIPTransport)
+				if isFakeIP && !allowFakeIP {
 					continue
 				}
 				displayRuleIndex := ruleIndex
@@ -64,7 +65,7 @@ func (r *Router) matchDNS(ctx context.Context, allowFakeIP bool, index int) (con
 					displayRuleIndex += index + 1
 				}
 				r.dnsLogger.DebugContext(ctx, "match[", displayRuleIndex, "] ", rule.String(), " => ", detour)
-				if rule.DisableCache() {
+				if (isFakeIP && !r.dnsIndependentCache) || rule.DisableCache() {
 					ctx = dns.ContextWithDisableCache(ctx, true)
 				}
 				if rewriteTTL := rule.RewriteTTL(); rewriteTTL != nil {
@@ -93,9 +94,10 @@ func (r *Router) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, er
 		r.dnsLogger.DebugContext(ctx, "exchange ", formatQuestion(message.Question[0].String()))
 	}
 	var (
-		response *mDNS.Msg
-		cached   bool
-		err      error
+		response  *mDNS.Msg
+		cached    bool
+		transport dns.Transport
+		err       error
 	)
 	response, cached = r.dnsClient.ExchangeCache(ctx, message)
 	if !cached {
@@ -112,7 +114,6 @@ func (r *Router) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, er
 			metadata.Domain = fqdnToDomain(message.Question[0].Name)
 		}
 		var (
-			transport dns.Transport
 			strategy  dns.DomainStrategy
 			rule      adapter.DNSRule
 			ruleIndex int
@@ -158,17 +159,22 @@ func (r *Router) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg, er
 			break
 		}
 	}
+	if err != nil {
+		return nil, err
+	}
 	if r.dnsReverseMapping != nil && len(message.Question) > 0 && response != nil && len(response.Answer) > 0 {
-		for _, answer := range response.Answer {
-			switch record := answer.(type) {
-			case *mDNS.A:
-				r.dnsReverseMapping.Save(M.AddrFromIP(record.A), fqdnToDomain(record.Hdr.Name), int(record.Hdr.Ttl))
-			case *mDNS.AAAA:
-				r.dnsReverseMapping.Save(M.AddrFromIP(record.AAAA), fqdnToDomain(record.Hdr.Name), int(record.Hdr.Ttl))
+		if _, isFakeIP := transport.(adapter.FakeIPTransport); !isFakeIP {
+			for _, answer := range response.Answer {
+				switch record := answer.(type) {
+				case *mDNS.A:
+					r.dnsReverseMapping.Save(M.AddrFromIP(record.A), fqdnToDomain(record.Hdr.Name), int(record.Hdr.Ttl))
+				case *mDNS.AAAA:
+					r.dnsReverseMapping.Save(M.AddrFromIP(record.AAAA), fqdnToDomain(record.Hdr.Name), int(record.Hdr.Ttl))
+				}
 			}
 		}
 	}
-	return response, err
+	return response, nil
 }
 
 func (r *Router) Lookup(ctx context.Context, domain string, strategy dns.DomainStrategy) ([]netip.Addr, error) {