diff --git a/pkg/transport/pktconns/udphop/parse.go b/pkg/transport/pktconns/udphop/common.go
similarity index 70%
rename from pkg/transport/pktconns/udphop/parse.go
rename to pkg/transport/pktconns/udphop/common.go
index 386a4d5..cfe13e5 100644
--- a/pkg/transport/pktconns/udphop/parse.go
+++ b/pkg/transport/pktconns/udphop/common.go
@@ -6,6 +6,11 @@ import (
 	"strings"
 )
 
+const (
+	packetQueueSize = 1024
+	udpBufferSize   = 2048
+)
+
 // parseAddr parses the listen address and returns the host and ports.
 // Format: "host:port1,port2,port3,..."
 func parseAddr(addr string) (host string, ports []uint16, err error) {
@@ -27,3 +32,21 @@ func parseAddr(addr string) (host string, ports []uint16, err error) {
 	}
 	return
 }
+
+type udpHopAddr struct {
+	listen string
+}
+
+func (a *udpHopAddr) Network() string {
+	return "udp-hop"
+}
+
+func (a *udpHopAddr) String() string {
+	return a.listen
+}
+
+type udpPacket struct {
+	buf  []byte
+	n    int
+	addr net.Addr
+}
diff --git a/pkg/transport/pktconns/udphop/server.go b/pkg/transport/pktconns/udphop/server.go
index 02af6fa..ecc13a2 100644
--- a/pkg/transport/pktconns/udphop/server.go
+++ b/pkg/transport/pktconns/udphop/server.go
@@ -12,8 +12,6 @@ import (
 )
 
 const (
-	packetQueueSize = 1024
-	udpBufferSize   = 2048
 	addrMapEntryTTL = time.Minute
 )
 
@@ -32,29 +30,11 @@ type ObfsUDPHopServerPacketConn struct {
 	bufPool sync.Pool
 }
 
-type udpPacket struct {
-	buf  []byte
-	n    int
-	addr net.Addr
-}
-
 type addrMapEntry struct {
 	index int
 	last  time.Time
 }
 
-type udpHopAddr struct {
-	listen string
-}
-
-func (a *udpHopAddr) Network() string {
-	return "udp-hop"
-}
-
-func (a *udpHopAddr) String() string {
-	return a.listen
-}
-
 func NewObfsUDPHopServerPacketConn(listen string, obfs obfs.Obfuscator) (*ObfsUDPHopServerPacketConn, error) {
 	host, ports, err := parseAddr(listen)
 	if err != nil {