From b7d3d0f3ff1ef70757b365182f5a1d23cb7a20db Mon Sep 17 00:00:00 2001
From: Jason <xjasonlyu@gmail.com>
Date: Tue, 16 Jul 2019 18:51:40 +0800
Subject: [PATCH] update IPToHost func

---
 common/dns/dns.go            | 2 +-
 common/dns/fakedns/server.go | 6 +++---
 proxy/dnsfallback/udp.go     | 4 ++--
 proxy/socks/tcp.go           | 4 ++--
 proxy/socks/udp.go           | 8 ++++----
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/common/dns/dns.go b/common/dns/dns.go
index ce8994b..bcdb79d 100644
--- a/common/dns/dns.go
+++ b/common/dns/dns.go
@@ -11,7 +11,7 @@ type FakeDns interface {
 	// GenerateFakeResponse(request []byte) ([]byte, error)
 
 	// IPToHost returns the corresponding domain for the given IP.
-	IPToHost(ip net.IP) string
+	IPToHost(ip net.IP) (string, bool)
 
 	// IsFakeIP checks if the given ip is a fake IP.
 	// IsFakeIP(ip net.IP) bool
diff --git a/common/dns/fakedns/server.go b/common/dns/fakedns/server.go
index c80256f..163b221 100644
--- a/common/dns/fakedns/server.go
+++ b/common/dns/fakedns/server.go
@@ -57,13 +57,13 @@ func (s *Server) StartServer(addr string) error {
 	return nil
 }
 
-func (s *Server) IPToHost(ip net.IP) string {
+func (s *Server) IPToHost(ip net.IP) (string, bool) {
 	c := s.c.Get(ip.String())
 	if c == nil {
-		return ""
+		return "", false
 	}
 	fqdn := c.(*D.Msg).Question[0].Name
-	return strings.TrimRight(fqdn, ".")
+	return strings.TrimRight(fqdn, "."), true
 }
 
 func NewServer(fakeIPRange, hostsLine string) (*Server, error) {
diff --git a/proxy/dnsfallback/udp.go b/proxy/dnsfallback/udp.go
index f2f0cdb..a0df811 100644
--- a/proxy/dnsfallback/udp.go
+++ b/proxy/dnsfallback/udp.go
@@ -28,14 +28,14 @@ func NewUDPHandler() core.UDPConnHandler {
 
 func (h *udpHandler) Connect(conn core.UDPConn, udpAddr *net.UDPAddr) error {
 	if udpAddr.Port != dns.CommonDnsPort {
-		return errors.New("Cannot handle non-DNS packet")
+		return errors.New("cannot handle non-DNS packet")
 	}
 	return nil
 }
 
 func (h *udpHandler) ReceiveTo(conn core.UDPConn, data []byte, addr *net.UDPAddr) error {
 	if len(data) < dnsHeaderLength {
-		return errors.New("Received malformed DNS query")
+		return errors.New("received malformed DNS query")
 	}
 	//  DNS Header
 	//  0  1  2  3  4  5  6  7  0  1  2  3  4  5  6  7
diff --git a/proxy/socks/tcp.go b/proxy/socks/tcp.go
index 797badf..88501e4 100644
--- a/proxy/socks/tcp.go
+++ b/proxy/socks/tcp.go
@@ -150,8 +150,8 @@ func (h *tcpHandler) Handle(conn net.Conn, target *net.TCPAddr) error {
 	// Replace with a domain name if target address IP is a fake IP.
 	var targetHost = target.IP.String()
 	if h.fakeDns != nil {
-		if t := h.fakeDns.IPToHost(target.IP); t != "" {
-			targetHost = t
+		if host, exist := h.fakeDns.IPToHost(target.IP); exist {
+			targetHost = host
 		}
 	}
 
diff --git a/proxy/socks/udp.go b/proxy/socks/udp.go
index c4d611e..7b3ce91 100644
--- a/proxy/socks/udp.go
+++ b/proxy/socks/udp.go
@@ -108,8 +108,8 @@ func (h *udpHandler) Connect(conn core.UDPConn, target *net.UDPAddr) error {
 				return nil // skip dns
 			}
 		*/
-		if t := h.fakeDns.IPToHost(target.IP); t != "" {
-			targetHost = t
+		if host, exist := h.fakeDns.IPToHost(target.IP); exist {
+			targetHost = host
 		}
 	}
 	dest := net.JoinHostPort(targetHost, strconv.Itoa(target.Port))
@@ -213,8 +213,8 @@ func (h *udpHandler) ReceiveTo(conn core.UDPConn, data []byte, addr *net.UDPAddr
 	if ok1 && ok2 {
 		var targetHost = addr.IP.String()
 		if h.fakeDns != nil {
-			if t := h.fakeDns.IPToHost(addr.IP); t != "" {
-				targetHost = t
+			if host, exist := h.fakeDns.IPToHost(addr.IP); exist {
+				targetHost = host
 			}
 		}