diff --git a/go.mod b/go.mod
index d1a86a6..4214425 100644
--- a/go.mod
+++ b/go.mod
@@ -8,7 +8,7 @@ require (
 	github.com/dgryski/go-idea v0.0.0-20170306091226-d2fb45a411fb
 	github.com/dgryski/go-rc2 v0.0.0-20150621095337-8a9021637152
 	github.com/ebfe/rc2 v0.0.0-20131011165748-24b9757f5521 // indirect
-	github.com/insomniacslk/dhcp v0.0.0-20210420214155-58efeba27ae8
+	github.com/insomniacslk/dhcp v0.0.0-20210428091707-95b2ff6905c9
 	github.com/klauspost/cpuid/v2 v2.0.6 // indirect
 	github.com/klauspost/reedsolomon v1.9.12 // indirect
 	github.com/mdlayher/raw v0.0.0-20210412142147-51b895745faf // indirect
@@ -17,7 +17,7 @@ require (
 	github.com/tjfoc/gmsm v1.4.0 // indirect
 	github.com/xtaci/kcp-go/v5 v5.6.1
 	golang.org/x/crypto v0.0.0-20210421170649-83a5a9bb288b
-	golang.org/x/net v0.0.0-20210423184538-5f58ad60dda6 // indirect
+	golang.org/x/net v0.0.0-20210428140749-89ef3d95e781 // indirect
 	golang.org/x/sys v0.0.0-20210426230700-d19ff857e887 // indirect
 )
 
diff --git a/go.sum b/go.sum
index decc2ed..8b90b8c 100644
--- a/go.sum
+++ b/go.sum
@@ -39,8 +39,8 @@ github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714 h1:/jC7qQFrv8CrSJVmaolDVOxTfS9kc36uB6H40kdbQq8=
 github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714/go.mod h1:2Goc3h8EklBH5mspfHFxBnEoURQCGzQQH1ga9Myjvis=
-github.com/insomniacslk/dhcp v0.0.0-20210420214155-58efeba27ae8 h1:RV5UbIISMfxSMcKwCZKrxVEhHcSfemkxpxcRXAmR0AM=
-github.com/insomniacslk/dhcp v0.0.0-20210420214155-58efeba27ae8/go.mod h1:TKl4jN3Voofo4UJIicyNhWGp/nlQqQkFxmwIFTvBkKI=
+github.com/insomniacslk/dhcp v0.0.0-20210428091707-95b2ff6905c9 h1:T+Czi1NGxrbx8enhcdUFPVYTpGd6DPDxrKptDXRgD8I=
+github.com/insomniacslk/dhcp v0.0.0-20210428091707-95b2ff6905c9/go.mod h1:TKl4jN3Voofo4UJIicyNhWGp/nlQqQkFxmwIFTvBkKI=
 github.com/jsimonetti/rtnetlink v0.0.0-20190606172950-9527aa82566a/go.mod h1:Oz+70psSo5OFh8DBl0Zv2ACw7Esh6pPUphlvZG9x7uw=
 github.com/jsimonetti/rtnetlink v0.0.0-20200117123717-f846d4f6c1f4/go.mod h1:WGuG/smIU4J/54PblvSbh+xvCZmpJnFgr3ds6Z55XMQ=
 github.com/jsimonetti/rtnetlink v0.0.0-20201009170750-9c6f07d100c1/go.mod h1:hqoO/u39cqLeBLebZ8fWdE96O7FxrAsRYhnVOdgHxok=
@@ -128,8 +128,8 @@ golang.org/x/net v0.0.0-20200707034311-ab3426394381/go.mod h1:/O7V0waA8r7cgGh81R
 golang.org/x/net v0.0.0-20201010224723-4f7140c49acb/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
-golang.org/x/net v0.0.0-20210423184538-5f58ad60dda6 h1:0PC75Fz/kyMGhL0e1QnypqK2kQMqKt9csD1GnMJR+Zk=
-golang.org/x/net v0.0.0-20210423184538-5f58ad60dda6/go.mod h1:OJAsFXCWl8Ukc7SiCT/9KSuxbyM7479/AVlXFRxuMCk=
+golang.org/x/net v0.0.0-20210428140749-89ef3d95e781 h1:DzZ89McO9/gWPsQXS/FVKAlG02ZjaQ6AlZRBimEYOd0=
+golang.org/x/net v0.0.0-20210428140749-89ef3d95e781/go.mod h1:OJAsFXCWl8Ukc7SiCT/9KSuxbyM7479/AVlXFRxuMCk=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
diff --git a/proxy/protocol/smux/session.go b/proxy/protocol/smux/session.go
index f8cfee7..3efec4d 100644
--- a/proxy/protocol/smux/session.go
+++ b/proxy/protocol/smux/session.go
@@ -4,8 +4,10 @@ import (
 	"container/heap"
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 	"net"
+	"os"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -21,8 +23,9 @@ var (
 	ErrInvalidProtocol = errors.New("invalid protocol")
 	ErrConsumed        = errors.New("peer consumed more than sent")
 	ErrGoAway          = errors.New("stream id overflows, should start a new connection")
-	ErrTimeout         = errors.New("timeout")
-	ErrWouldBlock      = errors.New("operation would block on IO")
+	// ErrTimeout         = errors.New("timeout")
+	ErrTimeout    = fmt.Errorf("smux: %w", os.ErrDeadlineExceeded)
+	ErrWouldBlock = errors.New("operation would block on IO")
 )
 
 type writeRequest struct {
diff --git a/proxy/smux/client.go b/proxy/smux/client.go
index a586364..21d9114 100644
--- a/proxy/smux/client.go
+++ b/proxy/smux/client.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"net"
 	"net/url"
+	"sync"
 
 	"github.com/nadoo/glider/log"
 	"github.com/nadoo/glider/proxy"
@@ -15,6 +16,7 @@ import (
 type SmuxClient struct {
 	dialer  proxy.Dialer
 	addr    string
+	mu      sync.Mutex
 	session *smux.Session
 }
 
@@ -66,6 +68,9 @@ func (s *SmuxClient) DialUDP(network, addr string) (net.PacketConn, net.Addr, er
 }
 
 func (s *SmuxClient) initConn() error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
 	conn, err := s.dialer.Dial("tcp", s.addr)
 	if err != nil {
 		log.F("[smux] dial to %s error: %s", s.addr, err)