add DNS caching

go.mod

@@ -14,6 +14,7 @@ require (
 )
 
 require (
+	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/valyala/fasthttp v1.33.0
 	golang.org/x/mod v0.5.1 // indirect
 	golang.org/x/net v0.0.0-20220225172249-27dd8689420f // indirect

go.sum

@@ -7,6 +7,8 @@ github.com/klauspost/compress v1.14.4 h1:eijASRJcobkVtSt81Olfh7JX43osYLwy5krOJo6
 github.com/klauspost/compress v1.14.4/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
 github.com/miekg/dns v1.1.46 h1:uzwpxRtSVxtcIZmz/4Uz6/Rn7G11DvsaslXoy5LxQio=
 github.com/miekg/dns v1.1.46/go.mod h1:e3IlAVfNqAllflbibAZEWOXOQ+Ynzk/dDozDxY7XnME=
+github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pelletier/go-toml v1.6.0/go.mod h1:5N711Q9dKgbdkxHL+MEfF31hpT7l0S0s/t2kKREewys=
 github.com/peterbourgon/ff/v3 v3.1.2 h1:0GNhbRhO9yHA4CC27ymskOsuRpmX0YQxwxM9UPiP6JM=
 github.com/peterbourgon/ff/v3 v3.1.2/go.mod h1:XNJLY8EIl6MjMVjBS4F0+G0LYoAqs0DTa4rmHHukKDE=

internal/stoppropaganda/customresolver/customresolver.go

@@ -0,0 +1,35 @@
+package customresolver
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/patrickmn/go-cache"
+)
+
+var resolver *net.Resolver
+var dnscache *cache.Cache
+
+type CustomResolver struct{}
+
+type Resolver interface {
+	LookupIPAddr(context.Context, string) (names []net.IPAddr, err error)
+}
+
+func (cs *CustomResolver) LookupIPAddr(ctx context.Context, host string) (names []net.IPAddr, err error) {
+	if c, found := dnscache.Get(host); found {
+		return c.([]net.IPAddr), nil
+	}
+
+	names, err = resolver.LookupIPAddr(ctx, host)
+	if err == nil {
+		dnscache.SetDefault(host, names)
+	}
+	return
+}
+
+func init() {
+	resolver = net.DefaultResolver
+	dnscache = cache.New(5*time.Minute, 10*time.Minute)
+}

internal/stoppropaganda/dns.go

@@ -30,6 +30,8 @@ type DNSServer struct {
 	target  string
 }
 
+var dnsClient *dns.Client
+
 var dnsServers = map[string]*DNSServer{}
 
 func startDNS() {

internal/stoppropaganda/stoppropaganda.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"time"
 
+	"github.com/erkexzcx/stoppropaganda/internal/stoppropaganda/customresolver"
 	"github.com/erkexzcx/stoppropaganda/internal/stoppropaganda/sockshttp"
 	"github.com/miekg/dns"
 	"github.com/peterbourgon/ff/v3"
@@ -36,10 +37,6 @@ func Start() {
 	panic(fasthttp.ListenAndServe(*flagBind, fasthttpRequestHandler))
 }
 
-var httpClient *fasthttp.Client
-
-var dnsClient *dns.Client
-
 func init() {
 	rand.Seed(time.Now().UnixNano())
 
@@ -82,12 +79,14 @@ func makeDialFunc() fasthttp.DialFunc {
 		masterDialer = MakeDialerThrough(dialer, proxyChain, proxyTimeout)
 	}
 
+	myResolver := &customresolver.CustomResolver{}
 	dial := (&TCPDialer{
-		Concurrency:      math.MaxInt,
+		Concurrency:      0,
 		DNSCacheDuration: 5 * time.Minute,
 
 		// stoppropaganda's implementation
 		ParentDialer: masterDialer,
+		Resolver:     myResolver,
 	}).Dial
 	return dial
 }

internal/stoppropaganda/websites.go

@@ -353,6 +353,8 @@ type Website struct {
 	req *fasthttp.Request
 }
 
+var httpClient *fasthttp.Client
+
 var websites = map[string]*Website{}
 
 func startWebsites() {
@@ -412,10 +414,17 @@ func runWebsiteWorker(c chan *Website) {
 			website.dnsLastChecked = time.Now()
 
 			if err != nil {
+				if strings.HasSuffix(err.Error(), "Temporary failure in name resolution") || strings.HasSuffix(err.Error(), "connection refused") {
+					website.mux.Lock()
+					website.Status = "Your DNS servers unreachable or returned an error"
+					website.mux.Unlock()
+					time.Sleep(1 * time.Second)
+					website.pauseMux.Unlock()
+					continue
+				}
+
 				website.mux.Lock()
 				switch {
-				case strings.HasSuffix(err.Error(), "Temporary failure in name resolution"):
-					website.Status = "Your DNS servers unreachable or returned an error"
 				case strings.HasSuffix(err.Error(), "no such host"):
 					website.Status = "Domain does not exist"
 				case strings.HasSuffix(err.Error(), "No address associated with hostname"):
@@ -426,7 +435,7 @@ func runWebsiteWorker(c chan *Website) {
 				website.paused = true
 				website.mux.Unlock()
 
-				time.Sleep(5 * time.Minute)
+				time.Sleep(10 * time.Second)
 				website.pauseMux.Unlock()
 				continue
 			}