fix: fix dns lookup on android

cli.go

 package main
 
 import (
+	"context"
 	"flag"
 	"log"
 	"math/rand"
+	"net"
 	"net/http"
 	_ "net/http/pprof" //nolint:gosec
 	"runtime"
@@ -36,6 +38,14 @@ func init() {
 	flag.StringVar(&account, "account", "unknown", "account")
 
 	flag.Parse()
+
+	// for android
+	net.DefaultResolver = &net.Resolver{
+		PreferGo: true,
+		Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+			return net.Dial("udp", common.DNSServer)
+		},
+	}
 }
 
 func initPprof() {

client/event.go

@@ -74,7 +74,7 @@ func (client *Client) WriteAndFlush(packet []byte) error {
 }
 
 func (client *Client) handleTransfer(packet *protocol.MajoraPacket) {
-	conn, ok := client.GetConnection(packet)
+	conn, ok := client.GetConnection(packet, "handleTransfer")
 	// 如何把这个错误告诉服务端
 	if !ok {
 		return
@@ -82,7 +82,7 @@ func (client *Client) handleTransfer(packet *protocol.MajoraPacket) {
 
 	if cnt, err := conn.Write(packet.Data); err != nil {
 		logger.Warn().Msgf("write with error cnt=%d|err=%+v", cnt, err)
-		client.RemoveConnection(packet, "write_error")
+		client.removeConnection(packet, "write_error")
 	}
 }
 
@@ -94,18 +94,18 @@ func (client *Client) handleConnection(conn net.Conn, packet *protocol.MajoraPac
 			if !errors.Is(err, net.ErrClosed) && !errors.Is(err, io.EOF) {
 				logger.Error().Msgf("handleConnection peek with error:%+v", err)
 			}
-			client.connStore.Delete(packet.SerialNumber)
+			client.removeConnection(packet, "peek_error")
 			break
 		}
 		bufsize := reader.Buffered()
+		logger.Debug().Msgf("bufsize %d", bufsize)
+
 		buf := make([]byte, bufsize)
 		_, err := reader.Read(buf)
 		if err != nil {
 			logger.Error().Msgf("handleConnection read with error:%+v", err)
 			break
 		}
-		logger.Debug().Msgf("handleConnection %s", string(buf))
-
 		pack := protocol.TypeTransfer.CreatePacket()
 		pack.Data = buf
 		pack.SerialNumber = packet.SerialNumber
@@ -117,11 +117,11 @@ func (client *Client) handleConnection(conn net.Conn, packet *protocol.MajoraPac
 }
 
 func (client *Client) handleDisconnectMessage(packet *protocol.MajoraPacket) {
-	client.RemoveConnection(packet, "from_server")
+	client.removeConnection(packet, "from_server")
 }
 
-func (client *Client) handleControlMessage(packet *protocol.MajoraPacket) {
-	logger.Debug().Msgf("handleControlMessage %s", string(packet.Data))
+func (client *Client) handleControlMessage(_ *protocol.MajoraPacket) {
+	logger.Debug().Msg("handleControlMessage ")
 }
 
 func (client *Client) handleDestroyMessage() {
@@ -142,15 +142,15 @@ func (client *Client) AddConnection(packet *protocol.MajoraPacket, conn net.Conn
 	logger.Debug().Msgf("create connection for %d", packet.SerialNumber)
 }
 
-// RemoveConnection 1. 本地缓存删除 2. 关闭连接  3. 通知natserver
-func (client *Client) RemoveConnection(packet *protocol.MajoraPacket, reason string) {
+// removeConnection 1. 本地缓存删除 2. 关闭连接  3. 通知natserver
+func (client *Client) removeConnection(packet *protocol.MajoraPacket, reason string) {
 	defer func() {
 		if err := recover(); err != nil {
-			logger.Error().Msgf("RemoveConnection panic %+v", err)
+			logger.Error().Msgf("removeConnection panic %+v", err)
 		}
 	}()
 	// delete from local cache
-	conn, ok := client.GetConnection(packet)
+	conn, ok := client.GetConnection(packet, "removeConnection")
 	if ok {
 		client.connStore.Delete(packet.SerialNumber)
 		// 直接关闭是否就可以  主动断开 是否有剩余数据已经意义不大了
@@ -167,13 +167,13 @@ func (client *Client) RemoveConnection(packet *protocol.MajoraPacket, reason str
 	}
 }
 
-func (client *Client) GetConnection(packet *protocol.MajoraPacket) (conn net.Conn, ok bool) {
+func (client *Client) GetConnection(packet *protocol.MajoraPacket, step string) (conn net.Conn, ok bool) {
 	load, ok := client.connStore.Load(packet.SerialNumber)
 
 	// 没有的话  可能是服务端未感知到端上的连接已断开了
 	// 是否需要主动创建一个
 	if !ok || load == nil {
-		logger.Warn().Msgf("can not find connection for %d", packet.SerialNumber)
+		logger.Warn().Msgf("can not find connection for %s->%d", step, packet.SerialNumber)
 		return nil, false
 	}
 	conn, ok = load.(net.Conn)

common/dns.go

+package common
+
+const (
+	DNSServer = "114.114.114.114:53"
+)