From bd4bc243315ab60b491b2e8abbf009eb7a74f52e Mon Sep 17 00:00:00 2001
From: Jason <xjasonlyu@gmail.com>
Date: Tue, 23 Jul 2019 16:00:56 +0800
Subject: [PATCH] remove lru cache

---
 cmd/tun2socks/main.go            |  1 -
 cmd/tun2socks/main_fakedns.go    |  3 +--
 common/dns/fakedns/middleware.go |  2 +-
 common/dns/fakedns/server.go     | 24 ++++++++----------------
 common/dns/fakedns/utils.go      | 19 +++++++++++++++++--
 5 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/cmd/tun2socks/main.go b/cmd/tun2socks/main.go
index 087da93..72f1a9c 100644
--- a/cmd/tun2socks/main.go
+++ b/cmd/tun2socks/main.go
@@ -50,7 +50,6 @@ type CmdArgs struct {
 	FakeIPRange          *string
 	FakeDnsAddr          *string
 	FakeDnsHosts         *string
-	DnsCacheSize         *int
 	ExceptionApps        *string
 	ExceptionSendThrough *string
 	Stats                *bool
diff --git a/cmd/tun2socks/main_fakedns.go b/cmd/tun2socks/main_fakedns.go
index 31c58e3..f5c71bc 100644
--- a/cmd/tun2socks/main_fakedns.go
+++ b/cmd/tun2socks/main_fakedns.go
@@ -13,11 +13,10 @@ func init() {
 	args.FakeDnsAddr = flag.String("fakeDnsAddr", ":53", "listen address of fake DNS")
 	args.FakeIPRange = flag.String("fakeIPRange", "198.18.0.1/16", "fake IP CIDR range for DNS")
 	args.FakeDnsHosts = flag.String("fakeDnsHosts", "", "Hosts mapping, e.g. 'a.com=1.1.1.1,b.net=2.2.2.2'")
-	args.DnsCacheSize = flag.Int("dnsCacheSize", 100, "Size of LRU-Cache to store DNS msg")
 
 	addPostFlagsInitFn(func() {
 		if *args.EnableFakeDns {
-			fakeDnsServer, err := fakedns.NewServer(*args.FakeIPRange, *args.FakeDnsHosts, *args.DnsCacheSize)
+			fakeDnsServer, err := fakedns.NewServer(*args.FakeIPRange, *args.FakeDnsHosts)
 			if err != nil {
 				panic("create fake dns server error")
 			}
diff --git a/common/dns/fakedns/middleware.go b/common/dns/fakedns/middleware.go
index 01e4369..be974ac 100644
--- a/common/dns/fakedns/middleware.go
+++ b/common/dns/fakedns/middleware.go
@@ -6,9 +6,9 @@ import (
 	"strings"
 
 	D "github.com/miekg/dns"
+	"github.com/xjasonlyu/tun2socks/common/cache"
 	trie "github.com/xjasonlyu/tun2socks/common/domain-trie"
 	"github.com/xjasonlyu/tun2socks/common/fakeip"
-	cache "github.com/xjasonlyu/tun2socks/common/lru-cache"
 )
 
 type handler func(w D.ResponseWriter, r *D.Msg)
diff --git a/common/dns/fakedns/server.go b/common/dns/fakedns/server.go
index 5084b3c..f2ba330 100644
--- a/common/dns/fakedns/server.go
+++ b/common/dns/fakedns/server.go
@@ -4,18 +4,19 @@ import (
 	"errors"
 	"net"
 	"strings"
+	"time"
 
 	D "github.com/miekg/dns"
+	"github.com/xjasonlyu/tun2socks/common/cache"
 	"github.com/xjasonlyu/tun2socks/common/fakeip"
-	cache "github.com/xjasonlyu/tun2socks/common/lru-cache"
 )
 
 const (
 	dnsFakeTTL    uint32 = 1
-	dnsDefaultTTL uint32 = 600
+	dnsDefaultTTL uint32 = 3600
 )
 
-// var cacheDuration = time.Duration(dnsDefaultTTL) * time.Second
+var cacheDuration = 10 * time.Minute
 
 type Server struct {
 	*D.Server
@@ -57,15 +58,15 @@ func (s *Server) StartServer(addr string) error {
 }
 
 func (s *Server) IPToHost(ip net.IP) (string, bool) {
-	c, ok := s.c.Peek(ip.String())
-	if !ok {
+	c := s.c.Get(ip.String())
+	if c == nil {
 		return "", false
 	}
 	fqdn := c.(*D.Msg).Question[0].Name
 	return strings.TrimRight(fqdn, "."), true
 }
 
-func NewServer(fakeIPRange, hostsLine string, size int) (*Server, error) {
+func NewServer(fakeIPRange, hostsLine string) (*Server, error) {
 	_, ipnet, err := net.ParseCIDR(fakeIPRange)
 	if err != nil {
 		return nil, err
@@ -75,16 +76,7 @@ func NewServer(fakeIPRange, hostsLine string, size int) (*Server, error) {
 		return nil, err
 	}
 
-	var cacheItem *cache.Cache
-	evictCallback := func(_ interface{}, value interface{}) {
-		msg := value.(*D.Msg).Copy()
-		q := msg.Question[0]
-		ip := msg.Answer[0].(*D.A).A
-		cacheItem.Remove("fakeip:" + q.String())
-		cacheItem.Remove(ip.String())
-	}
-	cacheItem = cache.New(size, evictCallback)
-
+	cacheItem := cache.New(cacheDuration)
 	hosts := lineToHosts(hostsLine)
 	handler := newHandler(hosts, cacheItem, pool)
 
diff --git a/common/dns/fakedns/utils.go b/common/dns/fakedns/utils.go
index b170bc0..e8d5fef 100644
--- a/common/dns/fakedns/utils.go
+++ b/common/dns/fakedns/utils.go
@@ -1,12 +1,27 @@
 package fakedns
 
 import (
+	"time"
+
+	"github.com/Dreamacro/clash/log"
 	D "github.com/miekg/dns"
-	cache "github.com/xjasonlyu/tun2socks/common/lru-cache"
+	"github.com/xjasonlyu/tun2socks/common/cache"
 )
 
 func putMsgToCache(c *cache.Cache, key string, msg *D.Msg) {
-	c.Add(key, msg.Copy())
+	var ttl time.Duration
+	if len(msg.Answer) != 0 {
+		ttl = time.Duration(msg.Answer[0].Header().Ttl) * time.Second
+	} else if len(msg.Ns) != 0 {
+		ttl = time.Duration(msg.Ns[0].Header().Ttl) * time.Second
+	} else if len(msg.Extra) != 0 {
+		ttl = time.Duration(msg.Extra[0].Header().Ttl) * time.Second
+	} else {
+		log.Debugln("[DNS] response msg error: %#v", msg)
+		return
+	}
+
+	c.Put(key, msg.Copy(), ttl)
 }
 
 func setMsgTTL(msg *D.Msg, ttl uint32) {