syncthing/lib/protocol/bep_extensions.go
greatroar 273cc9cef8
lib/rand: Various minor fixes (#6752)
crypto/rand output is cryptographically secure by the Go library
documentation's promise. That, rather than strength (= passes randomness
tests) is the property that Syncthing needs).
2020-06-17 10:43:58 +02:00

401 lines
10 KiB
Go

// Copyright (C) 2014 The Protocol Authors.
//go:generate go run ../../script/protofmt.go bep.proto
//go:generate protoc -I ../../ -I . --gogofast_out=. bep.proto
package protocol
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"runtime"
"time"
"github.com/syncthing/syncthing/lib/rand"
"github.com/syncthing/syncthing/lib/sha256"
)
const (
SyntheticDirectorySize = 128
HelloMessageMagic uint32 = 0x2EA7D90B
Version13HelloMagic uint32 = 0x9F79BC40 // old
)
// FileIntf is the set of methods implemented by both FileInfo and
// db.FileInfoTruncated.
type FileIntf interface {
FileSize() int64
FileName() string
FileLocalFlags() uint32
IsDeleted() bool
IsInvalid() bool
IsIgnored() bool
IsUnsupported() bool
MustRescan() bool
IsReceiveOnlyChanged() bool
IsDirectory() bool
IsSymlink() bool
ShouldConflict() bool
HasPermissionBits() bool
SequenceNo() int64
BlockSize() int
FileVersion() Vector
FileType() FileInfoType
FilePermissions() uint32
FileModifiedBy() ShortID
ModTime() time.Time
}
func (m Hello) Magic() uint32 {
return HelloMessageMagic
}
func (f FileInfo) String() string {
switch f.Type {
case FileInfoTypeDirectory:
return fmt.Sprintf("Directory{Name:%q, Sequence:%d, Permissions:0%o, ModTime:%v, Version:%v, Deleted:%v, Invalid:%v, LocalFlags:0x%x, NoPermissions:%v}",
f.Name, f.Sequence, f.Permissions, f.ModTime(), f.Version, f.Deleted, f.RawInvalid, f.LocalFlags, f.NoPermissions)
case FileInfoTypeFile:
return fmt.Sprintf("File{Name:%q, Sequence:%d, Permissions:0%o, ModTime:%v, Version:%v, Length:%d, Deleted:%v, Invalid:%v, LocalFlags:0x%x, NoPermissions:%v, BlockSize:%d, Blocks:%v}",
f.Name, f.Sequence, f.Permissions, f.ModTime(), f.Version, f.Size, f.Deleted, f.RawInvalid, f.LocalFlags, f.NoPermissions, f.RawBlockSize, f.Blocks)
case FileInfoTypeSymlink, FileInfoTypeDeprecatedSymlinkDirectory, FileInfoTypeDeprecatedSymlinkFile:
return fmt.Sprintf("Symlink{Name:%q, Type:%v, Sequence:%d, Version:%v, Deleted:%v, Invalid:%v, LocalFlags:0x%x, NoPermissions:%v, SymlinkTarget:%q}",
f.Name, f.Type, f.Sequence, f.Version, f.Deleted, f.RawInvalid, f.LocalFlags, f.NoPermissions, f.SymlinkTarget)
default:
panic("mystery file type detected")
}
}
func (f FileInfo) IsDeleted() bool {
return f.Deleted
}
func (f FileInfo) IsInvalid() bool {
return f.RawInvalid || f.LocalFlags&LocalInvalidFlags != 0
}
func (f FileInfo) IsUnsupported() bool {
return f.LocalFlags&FlagLocalUnsupported != 0
}
func (f FileInfo) IsIgnored() bool {
return f.LocalFlags&FlagLocalIgnored != 0
}
func (f FileInfo) MustRescan() bool {
return f.LocalFlags&FlagLocalMustRescan != 0
}
func (f FileInfo) IsReceiveOnlyChanged() bool {
return f.LocalFlags&FlagLocalReceiveOnly != 0
}
func (f FileInfo) IsDirectory() bool {
return f.Type == FileInfoTypeDirectory
}
func (f FileInfo) ShouldConflict() bool {
return f.LocalFlags&LocalConflictFlags != 0
}
func (f FileInfo) IsSymlink() bool {
switch f.Type {
case FileInfoTypeSymlink, FileInfoTypeDeprecatedSymlinkDirectory, FileInfoTypeDeprecatedSymlinkFile:
return true
default:
return false
}
}
func (f FileInfo) HasPermissionBits() bool {
return !f.NoPermissions
}
func (f FileInfo) FileSize() int64 {
if f.Deleted {
return 0
}
if f.IsDirectory() || f.IsSymlink() {
return SyntheticDirectorySize
}
return f.Size
}
func (f FileInfo) BlockSize() int {
if f.RawBlockSize == 0 {
return MinBlockSize
}
return int(f.RawBlockSize)
}
func (f FileInfo) FileName() string {
return f.Name
}
func (f FileInfo) FileLocalFlags() uint32 {
return f.LocalFlags
}
func (f FileInfo) ModTime() time.Time {
return time.Unix(f.ModifiedS, int64(f.ModifiedNs))
}
func (f FileInfo) SequenceNo() int64 {
return f.Sequence
}
func (f FileInfo) FileVersion() Vector {
return f.Version
}
func (f FileInfo) FileType() FileInfoType {
return f.Type
}
func (f FileInfo) FilePermissions() uint32 {
return f.Permissions
}
func (f FileInfo) FileModifiedBy() ShortID {
return f.ModifiedBy
}
// WinsConflict returns true if "f" is the one to choose when it is in
// conflict with "other".
func WinsConflict(f, other FileIntf) bool {
// If only one of the files is invalid, that one loses.
if f.IsInvalid() != other.IsInvalid() {
return !f.IsInvalid()
}
// If a modification is in conflict with a delete, we pick the
// modification.
if !f.IsDeleted() && other.IsDeleted() {
return true
}
if f.IsDeleted() && !other.IsDeleted() {
return false
}
// The one with the newer modification time wins.
if f.ModTime().After(other.ModTime()) {
return true
}
if f.ModTime().Before(other.ModTime()) {
return false
}
// The modification times were equal. Use the device ID in the version
// vector as tie breaker.
return f.FileVersion().Compare(other.FileVersion()) == ConcurrentGreater
}
func (f FileInfo) IsEmpty() bool {
return f.Version.Counters == nil
}
func (f FileInfo) IsEquivalent(other FileInfo, modTimeWindow time.Duration) bool {
return f.isEquivalent(other, modTimeWindow, false, false, 0)
}
func (f FileInfo) IsEquivalentOptional(other FileInfo, modTimeWindow time.Duration, ignorePerms bool, ignoreBlocks bool, ignoreFlags uint32) bool {
return f.isEquivalent(other, modTimeWindow, ignorePerms, ignoreBlocks, ignoreFlags)
}
// isEquivalent checks that the two file infos represent the same actual file content,
// i.e. it does purposely not check only selected (see below) struct members.
// Permissions (config) and blocks (scanning) can be excluded from the comparison.
// Any file info is not "equivalent", if it has different
// - type
// - deleted flag
// - invalid flag
// - permissions, unless they are ignored
// A file is not "equivalent", if it has different
// - modification time (difference bigger than modTimeWindow)
// - size
// - blocks, unless there are no blocks to compare (scanning)
// A symlink is not "equivalent", if it has different
// - target
// A directory does not have anything specific to check.
func (f FileInfo) isEquivalent(other FileInfo, modTimeWindow time.Duration, ignorePerms bool, ignoreBlocks bool, ignoreFlags uint32) bool {
if f.MustRescan() || other.MustRescan() {
// These are per definition not equivalent because they don't
// represent a valid state, even if both happen to have the
// MustRescan bit set.
return false
}
// Mask out the ignored local flags before checking IsInvalid() below
f.LocalFlags &^= ignoreFlags
other.LocalFlags &^= ignoreFlags
if f.Name != other.Name || f.Type != other.Type || f.Deleted != other.Deleted || f.IsInvalid() != other.IsInvalid() {
return false
}
if !ignorePerms && !f.NoPermissions && !other.NoPermissions && !PermsEqual(f.Permissions, other.Permissions) {
return false
}
switch f.Type {
case FileInfoTypeFile:
return f.Size == other.Size && ModTimeEqual(f.ModTime(), other.ModTime(), modTimeWindow) && (ignoreBlocks || f.BlocksEqual(other))
case FileInfoTypeSymlink:
return f.SymlinkTarget == other.SymlinkTarget
case FileInfoTypeDirectory:
return true
}
return false
}
func ModTimeEqual(a, b time.Time, modTimeWindow time.Duration) bool {
if a.Equal(b) {
return true
}
diff := a.Sub(b)
if diff < 0 {
diff *= -1
}
return diff < modTimeWindow
}
func PermsEqual(a, b uint32) bool {
switch runtime.GOOS {
case "windows":
// There is only writeable and read only, represented for user, group
// and other equally. We only compare against user.
return a&0600 == b&0600
default:
// All bits count
return a&0777 == b&0777
}
}
// BlocksEqual returns true when the two files have identical block lists.
func (f FileInfo) BlocksEqual(other FileInfo) bool {
// If both sides have blocks hashes then we can just compare those.
if len(f.BlocksHash) > 0 && len(other.BlocksHash) > 0 {
return bytes.Equal(f.BlocksHash, other.BlocksHash)
}
// Actually compare the block lists in full.
return blocksEqual(f.Blocks, other.Blocks)
}
// blocksEqual returns whether two slices of blocks are exactly the same hash
// and index pair wise.
func blocksEqual(a, b []BlockInfo) bool {
if len(b) != len(a) {
return false
}
for i, sblk := range a {
if !bytes.Equal(sblk.Hash, b[i].Hash) {
return false
}
}
return true
}
func (f *FileInfo) SetMustRescan(by ShortID) {
f.setLocalFlags(by, FlagLocalMustRescan)
}
func (f *FileInfo) SetIgnored(by ShortID) {
f.setLocalFlags(by, FlagLocalIgnored)
}
func (f *FileInfo) SetUnsupported(by ShortID) {
f.setLocalFlags(by, FlagLocalUnsupported)
}
func (f *FileInfo) SetDeleted(by ShortID) {
f.ModifiedBy = by
f.Deleted = true
f.Version = f.Version.Update(by)
f.ModifiedS = time.Now().Unix()
f.setNoContent()
}
func (f *FileInfo) setLocalFlags(by ShortID, flags uint32) {
f.RawInvalid = false
f.LocalFlags = flags
f.ModifiedBy = by
f.setNoContent()
}
func (f *FileInfo) setNoContent() {
f.Blocks = nil
f.BlocksHash = nil
f.Size = 0
}
func (b BlockInfo) String() string {
return fmt.Sprintf("Block{%d/%d/%d/%x}", b.Offset, b.Size, b.WeakHash, b.Hash)
}
// IsEmpty returns true if the block is a full block of zeroes.
func (b BlockInfo) IsEmpty() bool {
if v, ok := sha256OfEmptyBlock[int(b.Size)]; ok {
return bytes.Equal(b.Hash, v[:])
}
return false
}
type IndexID uint64
func (i IndexID) String() string {
return fmt.Sprintf("0x%016X", uint64(i))
}
func (i IndexID) Marshal() ([]byte, error) {
bs := make([]byte, 8)
binary.BigEndian.PutUint64(bs, uint64(i))
return bs, nil
}
func (i *IndexID) Unmarshal(bs []byte) error {
if len(bs) != 8 {
return errors.New("incorrect IndexID length")
}
*i = IndexID(binary.BigEndian.Uint64(bs))
return nil
}
func NewIndexID() IndexID {
return IndexID(rand.Uint64())
}
func (f Folder) Description() string {
// used by logging stuff
if f.Label == "" {
return f.ID
}
return fmt.Sprintf("%q (%s)", f.Label, f.ID)
}
func BlocksHash(bs []BlockInfo) []byte {
h := sha256.New()
for _, b := range bs {
_, _ = h.Write(b.Hash)
}
return h.Sum(nil)
}
func VectorHash(v Vector) []byte {
h := sha256.New()
for _, c := range v.Counters {
if err := binary.Write(h, binary.BigEndian, c.ID); err != nil {
panic("impossible: failed to write c.ID to hash function: " + err.Error())
}
if err := binary.Write(h, binary.BigEndian, c.Value); err != nil {
panic("impossible: failed to write c.Value to hash function: " + err.Error())
}
}
return h.Sum(nil)
}