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// Copyright (C) 2014 The Protocol Authors.
package protocol
import (
"bytes"
"encoding/base32"
"encoding/binary"
"errors"
"fmt"
"regexp"
"strings"
"github.com/syncthing/syncthing/lib/sha256"
"github.com/calmh/luhn"
)
const DeviceIDLength = 32
type DeviceID [DeviceIDLength]byte
type ShortID uint64
var (
LocalDeviceID = DeviceID{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
EmptyDeviceID = DeviceID{ /* all zeroes */ }
)
// NewDeviceID generates a new device ID from the raw bytes of a certificate
func NewDeviceID(rawCert []byte) DeviceID {
var n DeviceID
hf := sha256.New()
hf.Write(rawCert)
hf.Sum(n[:0])
return n
}
func DeviceIDFromString(s string) (DeviceID, error) {
var n DeviceID
err := n.UnmarshalText([]byte(s))
return n, err
}
func DeviceIDFromBytes(bs []byte) DeviceID {
var n DeviceID
if len(bs) != len(n) {
panic("incorrect length of byte slice representing device ID")
}
copy(n[:], bs)
return n
}
// String returns the canonical string representation of the device ID
func (n DeviceID) String() string {
if n == EmptyDeviceID {
return ""
}
id := base32.StdEncoding.EncodeToString(n[:])
id = strings.Trim(id, "=")
id, err := luhnify(id)
if err != nil {
// Should never happen
panic(err)
}
id = chunkify(id)
return id
}
func (n DeviceID) GoString() string {
return n.String()
}
func (n DeviceID) Compare(other DeviceID) int {
return bytes.Compare(n[:], other[:])
}
func (n DeviceID) Equals(other DeviceID) bool {
return bytes.Equal(n[:], other[:])
}
// Short returns an integer representing bits 0-63 of the device ID.
func (n DeviceID) Short() ShortID {
return ShortID(binary.BigEndian.Uint64(n[:]))
}
func (n *DeviceID) MarshalText() ([]byte, error) {
return []byte(n.String()), nil
}
func (s ShortID) String() string {
if s == 0 {
return ""
}
var bs [8]byte
binary.BigEndian.PutUint64(bs[:], uint64(s))
return base32.StdEncoding.EncodeToString(bs[:])[:7]
}
func (n *DeviceID) UnmarshalText(bs []byte) error {
id := string(bs)
id = strings.Trim(id, "=")
id = strings.ToUpper(id)
id = untypeoify(id)
id = unchunkify(id)
var err error
switch len(id) {
case 0:
*n = EmptyDeviceID
return nil
case 56:
// New style, with check digits
id, err = unluhnify(id)
if err != nil {
return err
}
fallthrough
case 52:
// Old style, no check digits
dec, err := base32.StdEncoding.DecodeString(id + "====")
if err != nil {
return err
}
copy(n[:], dec)
return nil
default:
return errors.New("device ID invalid: incorrect length")
}
}
func (n *DeviceID) ProtoSize() int {
// Used by protobuf marshaller.
return DeviceIDLength
}
func (n *DeviceID) MarshalTo(bs []byte) (int, error) {
// Used by protobuf marshaller.
if len(bs) < DeviceIDLength {
return 0, errors.New("destination too short")
}
copy(bs, (*n)[:])
return DeviceIDLength, nil
}
func (n *DeviceID) Unmarshal(bs []byte) error {
// Used by protobuf marshaller.
if len(bs) < DeviceIDLength {
return errors.New("not enough data")
}
copy((*n)[:], bs)
return nil
}
func luhnify(s string) (string, error) {
if len(s) != 52 {
panic("unsupported string length")
}
res := make([]string, 0, 4)
for i := 0; i < 4; i++ {
p := s[i*13 : (i+1)*13]
l, err := luhn.Base32.Generate(p)
if err != nil {
return "", err
}
res = append(res, fmt.Sprintf("%s%c", p, l))
}
return res[0] + res[1] + res[2] + res[3], nil
}
func unluhnify(s string) (string, error) {
if len(s) != 56 {
return "", fmt.Errorf("unsupported string length %d", len(s))
}
res := make([]string, 0, 4)
for i := 0; i < 4; i++ {
p := s[i*14 : (i+1)*14-1]
l, err := luhn.Base32.Generate(p)
if err != nil {
return "", err
}
if g := fmt.Sprintf("%s%c", p, l); g != s[i*14:(i+1)*14] {
return "", errors.New("check digit incorrect")
}
res = append(res, p)
}
return res[0] + res[1] + res[2] + res[3], nil
}
func chunkify(s string) string {
s = regexp.MustCompile("(.{7})").ReplaceAllString(s, "$1-")
s = strings.Trim(s, "-")
return s
}
func unchunkify(s string) string {
s = strings.Replace(s, "-", "", -1)
s = strings.Replace(s, " ", "", -1)
return s
}
func untypeoify(s string) string {
s = strings.Replace(s, "0", "O", -1)
s = strings.Replace(s, "1", "I", -1)
s = strings.Replace(s, "8", "B", -1)
return s
}
// DeviceIDs is a sortable slice of DeviceID
type DeviceIDs []DeviceID
func (l DeviceIDs) Len() int {
return len(l)
}
func (l DeviceIDs) Less(a, b int) bool {
return l[a].Compare(l[b]) == -1
}
func (l DeviceIDs) Swap(a, b int) {
l[a], l[b] = l[b], l[a]
}
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