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Cong Ding
2013-08-18 00:17:46 +02:00
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# Compiled Object files, Static and Dynamic libs (Shared Objects)
*.o
*.a
*.so
# Folders
_obj
_test
# Architecture specific extensions/prefixes
*.[568vq]
[568vq].out
*.cgo1.go
*.cgo2.c
_cgo_defun.c
_cgo_gotypes.go
_cgo_export.*
_testmain.go
*.exe

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Apache License
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http://www.apache.org/licenses/
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go-stun
=======
go-stun is a STUN (RFC 3489, 5389) client implementation in golang.
It is extremely easy to use -- just one line of code.
```go
import "github.com/ccding/go-stun/stun"
func main() {
nat, host, err := stun.Discover()
}
```
More details please go to `example.go`.

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// Copyright 2013, Cong Ding. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// author: Cong Ding <dinggnu@gmail.com>
//
package main
import (
"fmt"
"github.com/ccding/go-stun/stun"
)
func main() {
nat, host, err := stun.Discover()
if err != nil {
fmt.Println(err)
}
switch nat {
case stun.NAT_ERROR:
fmt.Println("Test failed")
case stun.NAT_UNKNOWN:
fmt.Println("Unexpected response from the STUN server")
case stun.NAT_BLOCKED:
fmt.Println("UDP is blocked")
case stun.NAT_FULL:
fmt.Println("Full cone NAT")
case stun.NAT_SYMETRIC:
fmt.Println("Symetric NAT")
case stun.NAT_RESTRICTED:
fmt.Println("Restricted NAT")
case stun.NAT_PORT_RESTRICTED:
fmt.Println("Port restricted NAT")
case stun.NAT_NONE:
fmt.Println("Not behind a NAT")
case stun.NAT_SYMETRIC_UDP_FIREWALL:
fmt.Println("Symetric UDP firewall")
}
if host != nil {
fmt.Println(host.Family())
fmt.Println(host.Ip())
fmt.Println(host.Port())
}
}

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// Copyright 2013, Cong Ding. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// author: Cong Ding <dinggnu@gmail.com>
//
package stun
import (
"encoding/binary"
"hash/crc32"
"net"
)
type attribute struct {
types uint16
length uint16
value []byte
}
func newAttribute(types uint16, value []byte) *attribute {
a := new(attribute)
a.types = types
a.value = padding(value)
a.length = uint16(len(a.value))
return a
}
func newFingerprintAttribute(packet *packet) *attribute {
crc := crc32.ChecksumIEEE(packet.bytes()) ^ FINGERPRINT
buf := make([]byte, 4)
binary.BigEndian.PutUint32(buf, crc)
return newAttribute(ATTRIBUTE_FINGERPRINT, buf)
}
func newSoftwareAttribute(packet *packet, name string) *attribute {
return newAttribute(ATTRIBUTE_SOFTWARE, []byte(name))
}
func newChangeReqAttribute(packet *packet, changeIp bool, changePort bool) *attribute {
value := make([]byte, 4)
if changeIp {
value[3] |= 0x04
}
if changePort {
value[3] |= 0x02
}
return newAttribute(ATTRIBUTE_CHANGE_REQUEST, value)
}
func (v *attribute) xorMappedAddr() *Host {
cookie := make([]byte, 4)
binary.BigEndian.PutUint32(cookie, MAGIC_COOKIE)
xorIp := make([]byte, 16)
for i := 0; i < len(v.value)-4; i++ {
xorIp[i] = v.value[i+4] ^ cookie[i]
}
port := binary.BigEndian.Uint16(v.value[2:4])
return &Host{binary.BigEndian.Uint16(v.value[0:2]),
net.IP(xorIp).String(), port ^ (MAGIC_COOKIE >> 32)}
}
func (v *attribute) address() *Host {
h := new(Host)
h.family = binary.BigEndian.Uint16(v.value[0:2])
h.port = binary.BigEndian.Uint16(v.value[2:4])
h.ip = net.IP(v.value[4:]).String()
return h
}

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// Copyright 2013, Cong Ding. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// author: Cong Ding <dinggnu@gmail.com>
//
package stun
import (
"errors"
"net"
"strconv"
)
var (
serverAddr string
softwareName string
)
func init() {
SetSoftwareName(DefaultSoftwareName)
}
func SetServerHost(host string, port int) error {
ips, err := net.LookupHost(host)
if err != nil {
return err
}
if len(ips) == 0 {
return errors.New("Failed to get IP address of " + host)
}
serverAddr = net.JoinHostPort(ips[0], strconv.Itoa(port))
return nil
}
func SetServerAddr(address string) {
serverAddr = address
}
func SetSoftwareName(name string) {
softwareName = name
}
func Discover() (int, *Host, error) {
if serverAddr == "" {
err := SetServerHost(DefaultServerHost, DefaultServerPort)
if err != nil {
return NAT_ERROR, nil, err
}
}
return discover()
}

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// Copyright 2013, Cong Ding. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// author: Cong Ding <dinggnu@gmail.com>
//
package stun
const (
DefaultServerHost = "provserver.televolution.net"
DefaultServerPort = 3478
DefaultSoftwareName = "StunClient"
)
const (
MAGIC_COOKIE = 0x2112A442
FINGERPRINT = 0x5354554e
)
const (
NAT_ERROR = iota
NAT_UNKNOWN
NAT_NONE
NAT_BLOCKED
NAT_FULL
NAT_SYMETRIC
NAT_RESTRICTED
NAT_PORT_RESTRICTED
NAT_SYMETRIC_UDP_FIREWALL
)
const (
ERROR_TRY_ALTERNATE = 300
ERROR_BAD_REQUEST = 400
ERROR_UNAUTHORIZED = 401
ERROR_UNASSIGNED_402 = 402
ERROR_FORBIDDEN = 403
ERROR_UNKNOWN_ATTRIBUTE = 420
ERROR_ALLOCATION_MISMATCH = 437
ERROR_STALE_NONCE = 438
ERROR_UNASSIGNED_439 = 439
ERROR_ADDRESS_FAMILY_NOT_SUPPORTED = 440
ERROR_WRONG_CREDENTIALS = 441
ERROR_UNSUPPORTED_TRANSPORT_PROTOCOL = 442
ERROR_PEER_ADDRESS_FAMILY_MISMATCH = 443
ERROR_CONNECTION_ALREADY_EXISTS = 446
ERROR_CONNECTION_TIMEOUT_OR_FAILURE = 447
ERROR_ALLOCATION_QUOTA_REACHED = 486
ERROR_ROLE_CONFLICT = 487
ERROR_SERVER_ERROR = 500
ERROR_INSUFFICIENT_CAPACITY = 508
)
const (
ATTRIBUTE_FAMILY_IPV4 = 0x01
ATTRIBUTE_FAMILY_IPV6 = 0x02
)
const (
ATTRIBUTE_MAPPED_ADDRESS = 0x0001
ATTRIBUTE_RESPONSE_ADDRESS = 0x0002
ATTRIBUTE_CHANGE_REQUEST = 0x0003
ATTRIBUTE_SOURCE_ADDRESS = 0x0004
ATTRIBUTE_CHANGED_ADDRESS = 0x0005
ATTRIBUTE_USERNAME = 0x0006
ATTRIBUTE_PASSWORD = 0x0007
ATTRIBUTE_MESSAGE_INTEGRITY = 0x0008
ATTRIBUTE_ERROR_CODE = 0x0009
ATTRIBUTE_UNKNOWN_ATTRIBUTES = 0x000A
ATTRIBUTE_REFLECTED_FROM = 0x000B
ATTRIBUTE_CHANNEL_NUMBER = 0x000C
ATTRIBUTE_LIFETIME = 0x000D
ATTRIBUTE_BANDWIDTH = 0x0010
ATTRIBUTE_XOR_PEER_ADDRESS = 0x0012
ATTRIBUTE_DATA = 0x0013
ATTRIBUTE_REALM = 0x0014
ATTRIBUTE_NONCE = 0x0015
ATTRIBUTE_XOR_RELAYED_ADDRESS = 0x0016
ATTRIBUTE_REQUESTED_ADDRESS_FAMILY = 0x0017
ATTRIBUTE_EVEN_PORT = 0x0018
ATTRIBUTE_REQUESTED_TRANSPORT = 0x0019
ATTRIBUTE_DONT_FRAGMENT = 0x001A
ATTRIBUTE_XOR_MAPPED_ADDRESS = 0x0020
ATTRIBUTE_TIMER_VAL = 0x0021
ATTRIBUTE_RESERVATION_TOKEN = 0x0022
ATTRIBUTE_PRIORITY = 0x0024
ATTRIBUTE_USE_CANDIDATE = 0x0025
ATTRIBUTE_PADDING = 0x0026
ATTRIBUTE_RESPONSE_PORT = 0x0027
ATTRIBUTE_CONNECTION_ID = 0x002A
ATTRIBUTE_XOR_MAPPED_ADDRESS_EXP = 0x8020
ATTRIBUTE_SOFTWARE = 0x8022
ATTRIBUTE_ALTERNATE_SERVER = 0x8023
ATTRIBUTE_CACHE_TIMEOUT = 0x8027
ATTRIBUTE_FINGERPRINT = 0x8028
ATTRIBUTE_ICE_CONTROLLED = 0x8029
ATTRIBUTE_ICE_CONTROLLING = 0x802A
ATTRIBUTE_RESPONSE_ORIGIN = 0x802B
ATTRIBUTE_OTHER_ADDRESS = 0x802C
ATTRIBUTE_ECN_CHECK_STUN = 0x802D
ATTRIBUTE_CISCO_FLOWDATA = 0xC000
)
const (
TYPE_BINDING_REQUEST = 0x0001
TYPE_BINDING_RESPONSE = 0x0101
TYPE_BINDING_ERROR_RESPONSE = 0x0111
TYPE_SHARED_SECRET_REQUEST = 0x0002
TYPE_SHARED_SECRET_RESPONSE = 0x0102
TYPE_SHARED_ERROR_RESPONSE = 0x0112
TYPE_ALLOCATE = 0x0003
TYPE_ALLOCATE_RESPONSE = 0x0103
TYPE_ALLOCATE_ERROR_RESPONSE = 0x0113
TYPE_REFRESH = 0x0004
TYPE_REFRESH_RESPONSE = 0x0104
TYPE_REFRESH_ERROR_RESPONSE = 0x0114
TYPE_SEND = 0x0006
TYPE_SEND_RESPONSE = 0x0106
TYPE_SEND_ERROR_RESPONSE = 0x0116
TYPE_DATA = 0x0007
TYPE_DATA_RESPONSE = 0x0107
TYPE_DATA_ERROR_RESPONSE = 0x0117
TYPE_CREATE_PERMISIION = 0x0008
TYPE_CREATE_PERMISIION_RESPONSE = 0x0108
TYPE_CREATE_PERMISIION_ERROR_RESPONSE = 0x0118
TYPE_CHANNEL_BINDING = 0x0009
TYPE_CHANNEL_BINDING_RESPONSE = 0x0109
TYPE_CHANNEL_BINDING_ERROR_RESPONSE = 0x0119
TYPE_CONNECT = 0x000A
TYPE_CONNECT_RESPONSE = 0x010A
TYPE_CONNECT_ERROR_RESPONSE = 0x011A
TYPE_CONNECTION_BIND = 0x000B
TYPE_CONNECTION_BIND_RESPONSE = 0x010B
TYPE_CONNECTION_BIND_ERROR_RESPONSE = 0x011B
TYPE_CONNECTION_ATTEMPT = 0x000C
TYPE_CONNECTION_ATTEMPT_RESPONSE = 0x010C
TYPE_CONNECTION_ATTEMPT_ERROR_RESPONSE = 0x011C
)

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// Copyright 2013, Cong Ding. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// author: Cong Ding <dinggnu@gmail.com>
//
package stun
import (
"errors"
"net"
)
// padding the length of the byte slice to multiple of 4
func padding(b []byte) []byte {
l := uint16(len(b))
return append(b, make([]byte, align(l)-l)...)
}
// align the uint16 number to the smallest multiple of 4, which is larger than
// or equal to the uint16 number
func align(l uint16) uint16 {
return (l + 3) & 0xfffc
}
func sendBindingReq(destAddr string) (*packet, string, error) {
connection, err := net.Dial("udp", destAddr)
if err != nil {
return nil, "", err
}
packet := newPacket()
packet.types = TYPE_BINDING_REQUEST
attribute := newSoftwareAttribute(packet, DefaultSoftwareName)
packet.addAttribute(*attribute)
attribute = newFingerprintAttribute(packet)
packet.addAttribute(*attribute)
localAddr := connection.LocalAddr().String()
packet, err = packet.send(connection)
if err != nil {
return nil, "", err
}
err = connection.Close()
return packet, localAddr, err
}
func sendChangeReq(changeIp bool, changePort bool) (*packet, error) {
connection, err := net.Dial("udp", serverAddr)
if err != nil {
return nil, err
}
// construct packet
packet := newPacket()
packet.types = TYPE_BINDING_REQUEST
attribute := newSoftwareAttribute(packet, DefaultSoftwareName)
packet.addAttribute(*attribute)
attribute = newChangeReqAttribute(packet, changeIp, changePort)
packet.addAttribute(*attribute)
attribute = newFingerprintAttribute(packet)
packet.addAttribute(*attribute)
packet, err = packet.send(connection)
if err != nil {
return nil, err
}
err = connection.Close()
return packet, err
}
func test1(destAddr string) (*packet, string, bool, *Host, error) {
packet, localAddr, err := sendBindingReq(destAddr)
if err != nil {
return nil, "", false, nil, err
}
if packet == nil {
return nil, "", false, nil, nil
}
hm := packet.xorMappedAddr()
// rfc 3489 doesn't require the server return xor mapped address
if hm == nil {
hm = packet.mappedAddr()
if hm == nil {
return nil, "", false, nil, errors.New("No mapped address")
}
}
hc := packet.changedAddr()
if hc == nil {
return nil, "", false, nil, errors.New("No changed address")
}
changeAddr := hc.Transport()
identical := localAddr == hm.Transport()
return packet, changeAddr, identical, hm, nil
}
func test2() (*packet, error) {
return sendChangeReq(true, true)
}
func test3() (*packet, error) {
return sendChangeReq(false, true)
}
// follow rfc 3489 and 5389
func discover() (int, *Host, error) {
packet, changeAddr, identical, host, err := test1(serverAddr)
if err != nil {
return NAT_ERROR, nil, err
}
if packet == nil {
return NAT_BLOCKED, nil, err
}
if identical {
packet, err = test2()
if err != nil {
return NAT_ERROR, host, err
}
if packet != nil {
return NAT_NONE, host, nil
}
return NAT_SYMETRIC_UDP_FIREWALL, host, nil
} else {
packet, err = test2()
if err != nil {
return NAT_ERROR, host, err
}
if packet != nil {
return NAT_FULL, host, nil
} else {
packet, _, identical, _, err := test1(changeAddr)
if err != nil {
return NAT_ERROR, host, err
}
if packet == nil {
// It should be NAT_BLOCKED, but will be
// detected in the first step. So this will
// never happen.
return NAT_UNKNOWN, host, nil
}
if identical {
packet, err = test3()
if err != nil {
return NAT_ERROR, host, err
}
if packet == nil {
return NAT_PORT_RESTRICTED, host, nil
} else {
return NAT_RESTRICTED, host, nil
}
} else {
return NAT_SYMETRIC, host, nil
}
}
}
}

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// Copyright 2013, Cong Ding. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// author: Cong Ding <dinggnu@gmail.com>
//
package stun
import (
"net"
"strconv"
)
type Host struct {
family uint16
ip string
port uint16
}
func (h *Host) Family() uint16 {
return h.family
}
func (h *Host) Ip() string {
return h.ip
}
func (h *Host) Port() uint16 {
return h.port
}
func (h *Host) Transport() string {
return net.JoinHostPort(h.ip, strconv.Itoa(int(h.port)))
}

144
stun/packet.go Normal file
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@@ -0,0 +1,144 @@
// Copyright 2013, Cong Ding. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// author: Cong Ding <dinggnu@gmail.com>
//
package stun
import (
"encoding/binary"
"net"
"time"
)
type packet struct {
types uint16
length uint16
cookie uint32
id []byte // 12 bytes
attributes []attribute
}
func newPacket() *packet {
v := new(packet)
v.id = make([]byte, 12)
v.attributes = make([]attribute, 0, 10)
v.cookie = MAGIC_COOKIE
v.length = 0
return v
}
func newPacketFromBytes(b []byte) *packet {
packet := newPacket()
packet.types = binary.BigEndian.Uint16(b[0:2])
packet.length = binary.BigEndian.Uint16(b[2:4])
packet.cookie = binary.BigEndian.Uint32(b[4:8])
packet.id = b[8:20]
for pos := uint16(20); pos < uint16(len(b)); {
types := binary.BigEndian.Uint16(b[pos : pos+2])
length := binary.BigEndian.Uint16(b[pos+2 : pos+4])
value := b[pos+4 : pos+4+length]
attribute := newAttribute(types, value)
packet.addAttribute(*attribute)
pos += align(length) + 4
}
return packet
}
func (v *packet) addAttribute(a attribute) {
v.attributes = append(v.attributes, a)
v.length += align(a.length) + 4
}
func (v *packet) bytes() []byte {
b := make([]byte, 8)
binary.BigEndian.PutUint16(b[0:2], v.types)
binary.BigEndian.PutUint16(b[2:4], v.length)
binary.BigEndian.PutUint32(b[4:8], v.cookie)
b = append(b, v.id...)
for _, a := range v.attributes {
buf := make([]byte, 2)
binary.BigEndian.PutUint16(buf, a.types)
b = append(b, buf...)
binary.BigEndian.PutUint16(buf, a.length)
b = append(b, buf...)
b = append(b, a.value...)
}
return b
}
func (v *packet) mappedAddr() *Host {
for _, a := range v.attributes {
if a.types == ATTRIBUTE_MAPPED_ADDRESS {
h := a.address()
return h
}
}
return nil
}
func (v *packet) changedAddr() *Host {
for _, a := range v.attributes {
if a.types == ATTRIBUTE_CHANGED_ADDRESS {
h := a.address()
return h
}
}
return nil
}
func (v *packet) xorMappedAddr() *Host {
for _, a := range v.attributes {
if (a.types == ATTRIBUTE_XOR_MAPPED_ADDRESS) || (a.types == ATTRIBUTE_XOR_MAPPED_ADDRESS_EXP) {
h := a.xorMappedAddr()
return h
}
}
return nil
}
// RFC 3489: Clients SHOULD retransmit the request starting with an interval
// of 100ms, doubling every retransmit until the interval reaches 1.6s.
// Retransmissions continue with intervals of 1.6s until a response is
// received, or a total of 9 requests have been sent.
func (packet *packet) send(conn net.Conn) (*packet, error) {
timeout := 100
for i := 0; i < 9; i++ {
l, err := conn.Write(packet.bytes())
if err != nil {
return nil, err
}
conn.SetReadDeadline(time.Now().Add(time.Duration(timeout) * time.Millisecond))
if timeout < 1600 {
timeout *= 2
}
b := make([]byte, 1024)
l, err = conn.Read(b)
if err == nil {
return newPacketFromBytes(b[0:l]), nil
} else {
if !err.(net.Error).Timeout() {
return nil, err
}
}
}
return nil, nil
}