use lru cache to store DNS

common/dns/fakedns/middleware.go

@@ -6,9 +6,10 @@ 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"
+	// "github.com/xjasonlyu/tun2socks/common/cache"
 )
 
 type handler func(w D.ResponseWriter, r *D.Msg)

common/dns/fakedns/server.go

@@ -4,11 +4,11 @@ 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"
+	// "github.com/xjasonlyu/tun2socks/common/cache"
 )
 
 const (
@@ -16,7 +16,9 @@ const (
 	dnsDefaultTTL uint32 = 600
 )
 
-var cacheDuration = time.Duration(dnsDefaultTTL) * time.Second
+// var cacheDuration = time.Duration(dnsDefaultTTL) * time.Second
+
+var cacheSize = 100
 
 type Server struct {
 	*D.Server
@@ -77,7 +79,7 @@ func NewServer(fakeIPRange, hostsLine string) (*Server, error) {
 	}
 
 	hosts := lineToHosts(hostsLine)
-	cacheItem := cache.New(cacheDuration)
+	cacheItem := cache.New(cacheSize)
 	handler := newHandler(hosts, cacheItem, pool)
 
 	return &Server{

common/dns/fakedns/util.go

@@ -1,12 +1,13 @@
 package fakedns
 
 import (
-	"time"
-
 	D "github.com/miekg/dns"
-	"github.com/xjasonlyu/tun2socks/common/cache"
+
+	cache "github.com/xjasonlyu/tun2socks/common/lru-cache"
+	// "github.com/xjasonlyu/tun2socks/common/cache"
 )
 
+/*
 func putMsgToCache(c *cache.Cache, key string, msg *D.Msg) {
 	var ttl time.Duration
 	if len(msg.Answer) != 0 {
@@ -21,6 +22,11 @@ func putMsgToCache(c *cache.Cache, key string, msg *D.Msg) {
 
 	c.Put(key, msg.Copy(), ttl)
 }
+*/
+
+func putMsgToCache(c *cache.Cache, key string, msg *D.Msg) {
+	c.Put(key, msg.Copy())
+}
 
 func setMsgTTL(msg *D.Msg, ttl uint32) {
 	for _, answer := range msg.Answer {

common/lru-cache/cache.go

@@ -0,0 +1,30 @@
+package cache
+
+import (
+	lru "github.com/hashicorp/golang-lru"
+)
+
+type Cache struct {
+	*lru.Cache
+}
+
+func (c *Cache) Purge() {
+	c.Cache.Purge()
+}
+
+func (c *Cache) Put(key interface{}, payload interface{}) {
+	_ = c.Cache.Add(key, payload)
+}
+
+func (c *Cache) Get(key interface{}) interface{} {
+	item, ok := c.Cache.Get(key)
+	if !ok {
+		return nil
+	}
+	return item
+}
+
+func New(size int) *Cache {
+	c, _ := lru.New(size)
+	return &Cache{c}
+}