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- // Copyright (C) 2014 The Protocol Authors.
- package protocol
- import (
- "bytes"
- "encoding/base32"
- "encoding/binary"
- "errors"
- "fmt"
- "strings"
- "github.com/syncthing/syncthing/lib/sha256"
- )
- const DeviceIDLength = 32
- type DeviceID [DeviceIDLength]byte
- type ShortID uint64
- var (
- LocalDeviceID = repeatedDeviceID(0xff)
- GlobalDeviceID = repeatedDeviceID(0xf8)
- EmptyDeviceID = DeviceID{ /* all zeroes */ }
- )
- func repeatedDeviceID(v byte) (d DeviceID) {
- for i := range d {
- d[i] = v
- }
- return
- }
- // NewDeviceID generates a new device ID from the raw bytes of a certificate
- func NewDeviceID(rawCert []byte) DeviceID {
- return DeviceID(sha256.Sum256(rawCert))
- }
- func DeviceIDFromString(s string) (DeviceID, error) {
- var n DeviceID
- err := n.UnmarshalText([]byte(s))
- return n, err
- }
- func DeviceIDFromBytes(bs []byte) (DeviceID, error) {
- var n DeviceID
- if len(bs) != len(n) {
- return n, errors.New("incorrect length of byte slice representing device ID")
- }
- copy(n[:], bs)
- return n, nil
- }
- // 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 fmt.Errorf("%q: device ID invalid: incorrect length", bs)
- }
- }
- func (*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 fmt.Errorf("%q: not enough data", bs)
- }
- copy((*n)[:], bs)
- return nil
- }
- func luhnify(s string) (string, error) {
- if len(s) != 52 {
- panic("unsupported string length")
- }
- res := make([]byte, 4*(13+1))
- for i := 0; i < 4; i++ {
- p := s[i*13 : (i+1)*13]
- copy(res[i*(13+1):], p)
- l, err := luhn32(p)
- if err != nil {
- return "", err
- }
- res[(i+1)*(13)+i] = byte(l)
- }
- return string(res), nil
- }
- func unluhnify(s string) (string, error) {
- if len(s) != 56 {
- return "", fmt.Errorf("%q: unsupported string length %d", s, len(s))
- }
- res := make([]byte, 52)
- for i := 0; i < 4; i++ {
- p := s[i*(13+1) : (i+1)*(13+1)-1]
- copy(res[i*13:], p)
- l, err := luhn32(p)
- if err != nil {
- return "", err
- }
- if s[(i+1)*14-1] != byte(l) {
- return "", fmt.Errorf("%q: check digit incorrect", s)
- }
- }
- return string(res), nil
- }
- func chunkify(s string) string {
- chunks := len(s) / 7
- res := make([]byte, chunks*(7+1)-1)
- for i := 0; i < chunks; i++ {
- if i > 0 {
- res[i*(7+1)-1] = '-'
- }
- copy(res[i*(7+1):], s[i*7:(i+1)*7])
- }
- return string(res)
- }
- func unchunkify(s string) string {
- s = strings.ReplaceAll(s, "-", "")
- s = strings.ReplaceAll(s, " ", "")
- return s
- }
- func untypeoify(s string) string {
- s = strings.ReplaceAll(s, "0", "O")
- s = strings.ReplaceAll(s, "1", "I")
- s = strings.ReplaceAll(s, "8", "B")
- return s
- }
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