Add 'lib/protocol/' from commit 'f91191218b192ace841c878f161832d19c09145a'

git-subtree-dir: lib/protocol
git-subtree-mainline: 5ecb8bdd8a44422a59f5cbc9abedd1d1717c4247
git-subtree-split: f91191218b192ace841c878f161832d19c09145a

lib/protocol/AUTHORS

@@ -0,0 +1,4 @@
+# This is the official list of Protocol Authors for copyright purposes.
+
+Audrius Butkevicius <[email protected]>
+Jakob Borg <[email protected]>

lib/protocol/CONTRIBUTING.md

@@ -0,0 +1,76 @@
+## Reporting Bugs
+
+Please file bugs in the [Github Issue
+Tracker](https://github.com/syncthing/protocol/issues).
+
+## Contributing Code
+
+Every contribution is welcome. Following the points below will make this
+a smoother process.
+
+Individuals making significant and valuable contributions are given
+commit-access to the project. If you make a significant contribution and
+are not considered for commit-access, please contact any of the
+Syncthing core team members.
+
+All nontrivial contributions should go through the pull request
+mechanism for internal review. Determining what is "nontrivial" is left
+at the discretion of the contributor.
+
+### Authorship
+
+All code authors are listed in the AUTHORS file. Commits must be made
+with the same name and email as listed in the AUTHORS file. To
+accomplish this, ensure that your git configuration is set correctly
+prior to making your first commit;
+
+    $ git config --global user.name "Jane Doe"
+    $ git config --global user.email [email protected]
+
+You must be reachable on the given email address. If you do not wish to
+use your real name for whatever reason, using a nickname or pseudonym is
+perfectly acceptable.
+
+## Coding Style
+
+- Follow the conventions laid out in [Effective Go](https://golang.org/doc/effective_go.html)
+  as much as makes sense.
+
+- All text files use Unix line endings.
+
+- Each commit should be `go fmt` clean.
+
+- The commit message subject should be a single short sentence
+  describing the change, starting with a capital letter.
+
+- Commits that resolve an existing issue must include the issue number
+  as `(fixes #123)` at the end of the commit message subject.
+
+- Imports are grouped per `goimports` standard; that is, standard
+  library first, then third party libraries after a blank line.
+
+- A contribution solving a single issue or introducing a single new
+  feature should probably be a single commit based on the current
+  `master` branch. You may be asked to "rebase" or "squash" your pull
+  request to make sure this is the case, especially if there have been
+  amendments during review.
+
+## Licensing
+
+All contributions are made under the same MIT license as the rest of the
+project, except documentation, user interface text and translation
+strings which are licensed under the Creative Commons Attribution 4.0
+International License. You retain the copyright to code you have
+written.
+
+When accepting your first contribution, the maintainer of the project
+will ensure that you are added to the AUTHORS file. You are welcome to
+add yourself as a separate commit in your first pull request.
+
+## Tests
+
+Yes please!
+
+## License
+
+MIT

lib/protocol/LICENSE

@@ -0,0 +1,19 @@
+Copyright (C) 2014-2015 The Protocol Authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+- The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

lib/protocol/README.md

@@ -0,0 +1,13 @@
+The BEPv1 Protocol
+==================
+
+[![Latest Build](http://img.shields.io/jenkins/s/http/build.syncthing.net/protocol.svg?style=flat-square)](http://build.syncthing.net/job/protocol/lastBuild/)
+[![API Documentation](http://img.shields.io/badge/api-Godoc-blue.svg?style=flat-square)](http://godoc.org/github.com/syncthing/protocol)
+[![MIT License](http://img.shields.io/badge/license-MIT-blue.svg?style=flat-square)](http://opensource.org/licenses/MIT)
+
+This is the protocol implementation used by Syncthing.
+
+License
+=======
+
+MIT

lib/protocol/common_test.go

@@ -0,0 +1,81 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"io"
+	"time"
+)
+
+type TestModel struct {
+	data     []byte
+	folder   string
+	name     string
+	offset   int64
+	size     int
+	hash     []byte
+	flags    uint32
+	options  []Option
+	closedCh chan bool
+}
+
+func newTestModel() *TestModel {
+	return &TestModel{
+		closedCh: make(chan bool),
+	}
+}
+
+func (t *TestModel) Index(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+}
+
+func (t *TestModel) IndexUpdate(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+}
+
+func (t *TestModel) Request(deviceID DeviceID, folder, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error {
+	t.folder = folder
+	t.name = name
+	t.offset = offset
+	t.size = len(buf)
+	t.hash = hash
+	t.flags = flags
+	t.options = options
+	copy(buf, t.data)
+	return nil
+}
+
+func (t *TestModel) Close(deviceID DeviceID, err error) {
+	close(t.closedCh)
+}
+
+func (t *TestModel) ClusterConfig(deviceID DeviceID, config ClusterConfigMessage) {
+}
+
+func (t *TestModel) isClosed() bool {
+	select {
+	case <-t.closedCh:
+		return true
+	case <-time.After(1 * time.Second):
+		return false // Timeout
+	}
+}
+
+type ErrPipe struct {
+	io.PipeWriter
+	written int
+	max     int
+	err     error
+	closed  bool
+}
+
+func (e *ErrPipe) Write(data []byte) (int, error) {
+	if e.closed {
+		return 0, e.err
+	}
+	if e.written+len(data) > e.max {
+		n, _ := e.PipeWriter.Write(data[:e.max-e.written])
+		e.PipeWriter.CloseWithError(e.err)
+		e.closed = true
+		return n, e.err
+	}
+	return e.PipeWriter.Write(data)
+}

lib/protocol/compression.go

@@ -0,0 +1,53 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+import "fmt"
+
+type Compression int
+
+const (
+	CompressMetadata Compression = iota // zero value is the default, default should be "metadata"
+	CompressNever
+	CompressAlways
+
+	compressionThreshold = 128 // don't bother compressing messages smaller than this many bytes
+)
+
+var compressionMarshal = map[Compression]string{
+	CompressNever:    "never",
+	CompressMetadata: "metadata",
+	CompressAlways:   "always",
+}
+
+var compressionUnmarshal = map[string]Compression{
+	// Legacy
+	"false": CompressNever,
+	"true":  CompressMetadata,
+
+	// Current
+	"never":    CompressNever,
+	"metadata": CompressMetadata,
+	"always":   CompressAlways,
+}
+
+func (c Compression) String() string {
+	s, ok := compressionMarshal[c]
+	if !ok {
+		return fmt.Sprintf("unknown:%d", c)
+	}
+	return s
+}
+
+func (c Compression) GoString() string {
+	return fmt.Sprintf("%q", c.String())
+}
+
+func (c Compression) MarshalText() ([]byte, error) {
+	return []byte(compressionMarshal[c]), nil
+}
+
+func (c *Compression) UnmarshalText(bs []byte) error {
+	*c = compressionUnmarshal[string(bs)]
+	return nil
+}

lib/protocol/compression_test.go

@@ -0,0 +1,49 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+import "testing"
+
+func TestCompressionMarshal(t *testing.T) {
+	uTestcases := []struct {
+		s string
+		c Compression
+	}{
+		{"true", CompressMetadata},
+		{"false", CompressNever},
+		{"never", CompressNever},
+		{"metadata", CompressMetadata},
+		{"always", CompressAlways},
+		{"whatever", CompressMetadata},
+	}
+
+	mTestcases := []struct {
+		s string
+		c Compression
+	}{
+		{"never", CompressNever},
+		{"metadata", CompressMetadata},
+		{"always", CompressAlways},
+	}
+
+	var c Compression
+	for _, tc := range uTestcases {
+		err := c.UnmarshalText([]byte(tc.s))
+		if err != nil {
+			t.Error(err)
+		}
+		if c != tc.c {
+			t.Errorf("%s unmarshalled to %d, not %d", tc.s, c, tc.c)
+		}
+	}
+
+	for _, tc := range mTestcases {
+		bs, err := tc.c.MarshalText()
+		if err != nil {
+			t.Error(err)
+		}
+		if s := string(bs); s != tc.s {
+			t.Errorf("%d marshalled to %q, not %q", tc.c, s, tc.s)
+		}
+	}
+}

lib/protocol/conflict_test.go

@@ -0,0 +1,23 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+import "testing"
+
+func TestWinsConflict(t *testing.T) {
+	testcases := [][2]FileInfo{
+		// The first should always win over the second
+		{{Modified: 42}, {Modified: 41}},
+		{{Modified: 41}, {Modified: 42, Flags: FlagDeleted}},
+		{{Modified: 41, Version: Vector{{42, 2}, {43, 1}}}, {Modified: 41, Version: Vector{{42, 1}, {43, 2}}}},
+	}
+
+	for _, tc := range testcases {
+		if !tc[0].WinsConflict(tc[1]) {
+			t.Errorf("%v should win over %v", tc[0], tc[1])
+		}
+		if tc[1].WinsConflict(tc[0]) {
+			t.Errorf("%v should not win over %v", tc[1], tc[0])
+		}
+	}
+}

lib/protocol/counting.go

@@ -0,0 +1,62 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"io"
+	"sync/atomic"
+	"time"
+)
+
+type countingReader struct {
+	io.Reader
+	tot  int64 // bytes
+	last int64 // unix nanos
+}
+
+var (
+	totalIncoming int64
+	totalOutgoing int64
+)
+
+func (c *countingReader) Read(bs []byte) (int, error) {
+	n, err := c.Reader.Read(bs)
+	atomic.AddInt64(&c.tot, int64(n))
+	atomic.AddInt64(&totalIncoming, int64(n))
+	atomic.StoreInt64(&c.last, time.Now().UnixNano())
+	return n, err
+}
+
+func (c *countingReader) Tot() int64 {
+	return atomic.LoadInt64(&c.tot)
+}
+
+func (c *countingReader) Last() time.Time {
+	return time.Unix(0, atomic.LoadInt64(&c.last))
+}
+
+type countingWriter struct {
+	io.Writer
+	tot  int64 // bytes
+	last int64 // unix nanos
+}
+
+func (c *countingWriter) Write(bs []byte) (int, error) {
+	n, err := c.Writer.Write(bs)
+	atomic.AddInt64(&c.tot, int64(n))
+	atomic.AddInt64(&totalOutgoing, int64(n))
+	atomic.StoreInt64(&c.last, time.Now().UnixNano())
+	return n, err
+}
+
+func (c *countingWriter) Tot() int64 {
+	return atomic.LoadInt64(&c.tot)
+}
+
+func (c *countingWriter) Last() time.Time {
+	return time.Unix(0, atomic.LoadInt64(&c.last))
+}
+
+func TotalInOut() (int64, int64) {
+	return atomic.LoadInt64(&totalIncoming), atomic.LoadInt64(&totalOutgoing)
+}

lib/protocol/debug.go

@@ -0,0 +1,15 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"os"
+	"strings"
+
+	"github.com/calmh/logger"
+)
+
+var (
+	debug = strings.Contains(os.Getenv("STTRACE"), "protocol") || os.Getenv("STTRACE") == "all"
+	l     = logger.DefaultLogger
+)

lib/protocol/deviceid.go

@@ -0,0 +1,163 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/base32"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/calmh/luhn"
+)
+
+type DeviceID [32]byte
+
+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}
+
+// 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 {
+	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.Compare(n[:], other[:]) == 0
+}
+
+// Short returns an integer representing bits 0-63 of the device ID.
+func (n DeviceID) Short() uint64 {
+	return binary.BigEndian.Uint64(n[:])
+}
+
+func (n *DeviceID) MarshalText() ([]byte, error) {
+	return []byte(n.String()), nil
+}
+
+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 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 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
+}

lib/protocol/deviceid_test.go

@@ -0,0 +1,76 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import "testing"
+
+var formatted = "P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2"
+var formatCases = []string{
+	"P56IOI-7MZJNU-2IQGDR-EYDM2M-GTMGL3-BXNPQ6-W5BTBB-Z4TJXZ-WICQ",
+	"P56IOI-7MZJNU2Y-IQGDR-EYDM2M-GTI-MGL3-BXNPQ6-W5BM-TBB-Z4TJXZ-WICQ2",
+	"P56IOI7 MZJNU2I QGDREYD M2MGTMGL 3BXNPQ6W 5BTB BZ4T JXZWICQ",
+	"P56IOI7 MZJNU2Y IQGDREY DM2MGTI MGL3BXN PQ6W5BM TBBZ4TJ XZWICQ2",
+	"P56IOI7MZJNU2IQGDREYDM2MGTMGL3BXNPQ6W5BTBBZ4TJXZWICQ",
+	"p56ioi7mzjnu2iqgdreydm2mgtmgl3bxnpq6w5btbbz4tjxzwicq",
+	"P56IOI7MZJNU2YIQGDREYDM2MGTIMGL3BXNPQ6W5BMTBBZ4TJXZWICQ2",
+	"P561017MZJNU2YIQGDREYDM2MGTIMGL3BXNPQ6W5BMT88Z4TJXZWICQ2",
+	"p56ioi7mzjnu2yiqgdreydm2mgtimgl3bxnpq6w5bmtbbz4tjxzwicq2",
+	"p561017mzjnu2yiqgdreydm2mgtimgl3bxnpq6w5bmt88z4tjxzwicq2",
+}
+
+func TestFormatDeviceID(t *testing.T) {
+	for i, tc := range formatCases {
+		var id DeviceID
+		err := id.UnmarshalText([]byte(tc))
+		if err != nil {
+			t.Errorf("#%d UnmarshalText(%q); %v", i, tc, err)
+		} else if f := id.String(); f != formatted {
+			t.Errorf("#%d FormatDeviceID(%q)\n\t%q !=\n\t%q", i, tc, f, formatted)
+		}
+	}
+}
+
+var validateCases = []struct {
+	s  string
+	ok bool
+}{
+	{"", false},
+	{"P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2", true},
+	{"P56IOI7-MZJNU2-IQGDREY-DM2MGT-MGL3BXN-PQ6W5B-TBBZ4TJ-XZWICQ", true},
+	{"P56IOI7 MZJNU2I QGDREYD M2MGTMGL 3BXNPQ6W 5BTB BZ4T JXZWICQ", true},
+	{"P56IOI7MZJNU2IQGDREYDM2MGTMGL3BXNPQ6W5BTBBZ4TJXZWICQ", true},
+	{"P56IOI7MZJNU2IQGDREYDM2MGTMGL3BXNPQ6W5BTBBZ4TJXZWICQCCCC", false},
+	{"p56ioi7mzjnu2iqgdreydm2mgtmgl3bxnpq6w5btbbz4tjxzwicq", true},
+	{"p56ioi7mzjnu2iqgdreydm2mgtmgl3bxnpq6w5btbbz4tjxzwicqCCCC", false},
+}
+
+func TestValidateDeviceID(t *testing.T) {
+	for _, tc := range validateCases {
+		var id DeviceID
+		err := id.UnmarshalText([]byte(tc.s))
+		if (err == nil && !tc.ok) || (err != nil && tc.ok) {
+			t.Errorf("ValidateDeviceID(%q); %v != %v", tc.s, err, tc.ok)
+		}
+	}
+}
+
+func TestMarshallingDeviceID(t *testing.T) {
+	n0 := DeviceID{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 10, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32}
+	n1 := DeviceID{}
+	n2 := DeviceID{}
+
+	bs, _ := n0.MarshalText()
+	n1.UnmarshalText(bs)
+	bs, _ = n1.MarshalText()
+	n2.UnmarshalText(bs)
+
+	if n2.String() != n0.String() {
+		t.Errorf("String marshalling error; %q != %q", n2.String(), n0.String())
+	}
+	if !n2.Equals(n0) {
+		t.Error("Equals error")
+	}
+	if n2.Compare(n0) != 0 {
+		t.Error("Compare error")
+	}
+}

lib/protocol/doc.go

@@ -0,0 +1,4 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+// Package protocol implements the Block Exchange Protocol.
+package protocol

lib/protocol/errors.go

@@ -0,0 +1,51 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"errors"
+)
+
+const (
+	ecNoError int32 = iota
+	ecGeneric
+	ecNoSuchFile
+	ecInvalid
+)
+
+var (
+	ErrNoError    error = nil
+	ErrGeneric          = errors.New("generic error")
+	ErrNoSuchFile       = errors.New("no such file")
+	ErrInvalid          = errors.New("file is invalid")
+)
+
+var lookupError = map[int32]error{
+	ecNoError:    ErrNoError,
+	ecGeneric:    ErrGeneric,
+	ecNoSuchFile: ErrNoSuchFile,
+	ecInvalid:    ErrInvalid,
+}
+
+var lookupCode = map[error]int32{
+	ErrNoError:    ecNoError,
+	ErrGeneric:    ecGeneric,
+	ErrNoSuchFile: ecNoSuchFile,
+	ErrInvalid:    ecInvalid,
+}
+
+func codeToError(errcode int32) error {
+	err, ok := lookupError[errcode]
+	if !ok {
+		return ErrGeneric
+	}
+	return err
+}
+
+func errorToCode(err error) int32 {
+	code, ok := lookupCode[err]
+	if !ok {
+		return ecGeneric
+	}
+	return code
+}

lib/protocol/fuzz.go

@@ -0,0 +1,70 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+// +build gofuzz
+
+package protocol
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+	"reflect"
+	"sync"
+)
+
+func Fuzz(data []byte) int {
+	// Regenerate the length, or we'll most commonly exit quickly due to an
+	// unexpected eof which is unintestering.
+	if len(data) > 8 {
+		binary.BigEndian.PutUint32(data[4:], uint32(len(data))-8)
+	}
+
+	// Setup a rawConnection we'll use to parse the message.
+	c := rawConnection{
+		cr:     &countingReader{Reader: bytes.NewReader(data)},
+		closed: make(chan struct{}),
+		pool: sync.Pool{
+			New: func() interface{} {
+				return make([]byte, BlockSize)
+			},
+		},
+	}
+
+	// Attempt to parse the message.
+	hdr, msg, err := c.readMessage()
+	if err != nil {
+		return 0
+	}
+
+	// If parsing worked, attempt to encode it again.
+	newBs, err := msg.AppendXDR(nil)
+	if err != nil {
+		panic("not encodable")
+	}
+
+	// Create an appriate header for the re-encoding.
+	newMsg := make([]byte, 8)
+	binary.BigEndian.PutUint32(newMsg, encodeHeader(hdr))
+	binary.BigEndian.PutUint32(newMsg[4:], uint32(len(newBs)))
+	newMsg = append(newMsg, newBs...)
+
+	// Use the rawConnection to parse the re-encoding.
+	c.cr = &countingReader{Reader: bytes.NewReader(newMsg)}
+	hdr2, msg2, err := c.readMessage()
+	if err != nil {
+		fmt.Println("Initial:\n" + hex.Dump(data))
+		fmt.Println("New:\n" + hex.Dump(newMsg))
+		panic("not parseable after re-encode: " + err.Error())
+	}
+
+	// Make sure the data is the same as it was before.
+	if hdr != hdr2 {
+		panic("headers differ")
+	}
+	if !reflect.DeepEqual(msg, msg2) {
+		panic("contents differ")
+	}
+
+	return 1
+}

lib/protocol/fuzz_test.go

@@ -0,0 +1,89 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+// +build gofuzz
+
+package protocol
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+	"testing/quick"
+)
+
+// This can be used to generate a corpus of valid messages as a starting point
+// for the fuzzer.
+func TestGenerateCorpus(t *testing.T) {
+	t.Skip("Use to generate initial corpus only")
+
+	n := 0
+	check := func(idx IndexMessage) bool {
+		for i := range idx.Options {
+			if len(idx.Options[i].Key) > 64 {
+				idx.Options[i].Key = idx.Options[i].Key[:64]
+			}
+		}
+		hdr := header{
+			version:     0,
+			msgID:       42,
+			msgType:     messageTypeIndex,
+			compression: false,
+		}
+
+		msgBs := idx.MustMarshalXDR()
+
+		buf := make([]byte, 8)
+		binary.BigEndian.PutUint32(buf, encodeHeader(hdr))
+		binary.BigEndian.PutUint32(buf[4:], uint32(len(msgBs)))
+		buf = append(buf, msgBs...)
+
+		ioutil.WriteFile(fmt.Sprintf("testdata/corpus/test-%03d.xdr", n), buf, 0644)
+		n++
+		return true
+	}
+
+	if err := quick.Check(check, &quick.Config{MaxCount: 1000}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Tests any crashers found by the fuzzer, for closer investigation.
+func TestCrashers(t *testing.T) {
+	testFiles(t, "testdata/crashers")
+}
+
+// Tests the entire corpus, which should PASS before the fuzzer starts
+// fuzzing.
+func TestCorpus(t *testing.T) {
+	testFiles(t, "testdata/corpus")
+}
+
+func testFiles(t *testing.T, dir string) {
+	fd, err := os.Open(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	crashers, err := fd.Readdirnames(-1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, name := range crashers {
+		if strings.HasSuffix(name, ".output") {
+			continue
+		}
+		if strings.HasSuffix(name, ".quoted") {
+			continue
+		}
+
+		t.Log(name)
+		crasher, err := ioutil.ReadFile(dir + "/" + name)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		Fuzz(crasher)
+	}
+}

lib/protocol/header.go

@@ -0,0 +1,43 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import "github.com/calmh/xdr"
+
+type header struct {
+	version     int
+	msgID       int
+	msgType     int
+	compression bool
+}
+
+func (h header) encodeXDR(xw *xdr.Writer) (int, error) {
+	u := encodeHeader(h)
+	return xw.WriteUint32(u)
+}
+
+func (h *header) decodeXDR(xr *xdr.Reader) error {
+	u := xr.ReadUint32()
+	*h = decodeHeader(u)
+	return xr.Error()
+}
+
+func encodeHeader(h header) uint32 {
+	var isComp uint32
+	if h.compression {
+		isComp = 1 << 0 // the zeroth bit is the compression bit
+	}
+	return uint32(h.version&0xf)<<28 +
+		uint32(h.msgID&0xfff)<<16 +
+		uint32(h.msgType&0xff)<<8 +
+		isComp
+}
+
+func decodeHeader(u uint32) header {
+	return header{
+		version:     int(u>>28) & 0xf,
+		msgID:       int(u>>16) & 0xfff,
+		msgType:     int(u>>8) & 0xff,
+		compression: u&1 == 1,
+	}
+}

lib/protocol/message.go

@@ -0,0 +1,152 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+//go:generate -command genxdr go run ../syncthing/Godeps/_workspace/src/github.com/calmh/xdr/cmd/genxdr/main.go
+//go:generate genxdr -o message_xdr.go message.go
+
+package protocol
+
+import "fmt"
+
+type IndexMessage struct {
+	Folder  string
+	Files   []FileInfo // max:1000000
+	Flags   uint32
+	Options []Option // max:64
+}
+
+type FileInfo struct {
+	Name         string // max:8192
+	Flags        uint32
+	Modified     int64
+	Version      Vector
+	LocalVersion int64
+	CachedSize   int64       // noencode (cache only)
+	Blocks       []BlockInfo // max:1000000
+}
+
+func (f FileInfo) String() string {
+	return fmt.Sprintf("File{Name:%q, Flags:0%o, Modified:%d, Version:%v, Size:%d, Blocks:%v}",
+		f.Name, f.Flags, f.Modified, f.Version, f.Size(), f.Blocks)
+}
+
+func (f FileInfo) Size() (bytes int64) {
+	if f.IsDeleted() || f.IsDirectory() {
+		return 128
+	}
+	for _, b := range f.Blocks {
+		bytes += int64(b.Size)
+	}
+	return
+}
+
+func (f FileInfo) IsDeleted() bool {
+	return f.Flags&FlagDeleted != 0
+}
+
+func (f FileInfo) IsInvalid() bool {
+	return f.Flags&FlagInvalid != 0
+}
+
+func (f FileInfo) IsDirectory() bool {
+	return f.Flags&FlagDirectory != 0
+}
+
+func (f FileInfo) IsSymlink() bool {
+	return f.Flags&FlagSymlink != 0
+}
+
+func (f FileInfo) HasPermissionBits() bool {
+	return f.Flags&FlagNoPermBits == 0
+}
+
+// WinsConflict returns true if "f" is the one to choose when it is in
+// conflict with "other".
+func (f FileInfo) WinsConflict(other FileInfo) bool {
+	// 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.Modified > other.Modified {
+		return true
+	}
+	if f.Modified < other.Modified {
+		return false
+	}
+
+	// The modification times were equal. Use the device ID in the version
+	// vector as tie breaker.
+	return f.Version.Compare(other.Version) == ConcurrentGreater
+}
+
+type BlockInfo struct {
+	Offset int64 // noencode (cache only)
+	Size   int32
+	Hash   []byte // max:64
+}
+
+func (b BlockInfo) String() string {
+	return fmt.Sprintf("Block{%d/%d/%x}", b.Offset, b.Size, b.Hash)
+}
+
+type RequestMessage struct {
+	Folder  string // max:64
+	Name    string // max:8192
+	Offset  int64
+	Size    int32
+	Hash    []byte // max:64
+	Flags   uint32
+	Options []Option // max:64
+}
+
+type ResponseMessage struct {
+	Data []byte
+	Code int32
+}
+
+type ClusterConfigMessage struct {
+	ClientName    string   // max:64
+	ClientVersion string   // max:64
+	Folders       []Folder // max:1000000
+	Options       []Option // max:64
+}
+
+func (o *ClusterConfigMessage) GetOption(key string) string {
+	for _, option := range o.Options {
+		if option.Key == key {
+			return option.Value
+		}
+	}
+	return ""
+}
+
+type Folder struct {
+	ID      string   // max:64
+	Devices []Device // max:1000000
+	Flags   uint32
+	Options []Option // max:64
+}
+
+type Device struct {
+	ID              []byte // max:32
+	MaxLocalVersion int64
+	Flags           uint32
+	Options         []Option // max:64
+}
+
+type Option struct {
+	Key   string // max:64
+	Value string // max:1024
+}
+
+type CloseMessage struct {
+	Reason string // max:1024
+	Code   int32
+}
+
+type EmptyMessage struct{}

lib/protocol/message_xdr.go

@@ -0,0 +1,1136 @@
+// ************************************************************
+// This file is automatically generated by genxdr. Do not edit.
+// ************************************************************
+
+package protocol
+
+import (
+	"bytes"
+	"io"
+
+	"github.com/calmh/xdr"
+)
+
+/*
+
+IndexMessage Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Length of Folder                        |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                   Folder (variable length)                    \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                        Number of Files                        |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\               Zero or more FileInfo Structures                \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Flags                             |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Options                       |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                Zero or more Option Structures                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct IndexMessage {
+	string Folder<>;
+	FileInfo Files<1000000>;
+	unsigned int Flags;
+	Option Options<64>;
+}
+
+*/
+
+func (o IndexMessage) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o IndexMessage) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o IndexMessage) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o IndexMessage) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o IndexMessage) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	xw.WriteString(o.Folder)
+	if l := len(o.Files); l > 1000000 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Files", l, 1000000)
+	}
+	xw.WriteUint32(uint32(len(o.Files)))
+	for i := range o.Files {
+		_, err := o.Files[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	xw.WriteUint32(o.Flags)
+	if l := len(o.Options); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Options", l, 64)
+	}
+	xw.WriteUint32(uint32(len(o.Options)))
+	for i := range o.Options {
+		_, err := o.Options[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	return xw.Tot(), xw.Error()
+}
+
+func (o *IndexMessage) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *IndexMessage) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *IndexMessage) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.Folder = xr.ReadString()
+	_FilesSize := int(xr.ReadUint32())
+	if _FilesSize < 0 {
+		return xdr.ElementSizeExceeded("Files", _FilesSize, 1000000)
+	}
+	if _FilesSize > 1000000 {
+		return xdr.ElementSizeExceeded("Files", _FilesSize, 1000000)
+	}
+	o.Files = make([]FileInfo, _FilesSize)
+	for i := range o.Files {
+		(&o.Files[i]).DecodeXDRFrom(xr)
+	}
+	o.Flags = xr.ReadUint32()
+	_OptionsSize := int(xr.ReadUint32())
+	if _OptionsSize < 0 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	if _OptionsSize > 64 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	o.Options = make([]Option, _OptionsSize)
+	for i := range o.Options {
+		(&o.Options[i]).DecodeXDRFrom(xr)
+	}
+	return xr.Error()
+}
+
+/*
+
+FileInfo Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                        Length of Name                         |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                    Name (variable length)                     \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Flags                             |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                                                               |
++                      Modified (64 bits)                       +
+|                                                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                       Vector Structure                        \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                                                               |
++                    Local Version (64 bits)                    +
+|                                                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Blocks                        |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\               Zero or more BlockInfo Structures               \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct FileInfo {
+	string Name<8192>;
+	unsigned int Flags;
+	hyper Modified;
+	Vector Version;
+	hyper LocalVersion;
+	BlockInfo Blocks<1000000>;
+}
+
+*/
+
+func (o FileInfo) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o FileInfo) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o FileInfo) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o FileInfo) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o FileInfo) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	if l := len(o.Name); l > 8192 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Name", l, 8192)
+	}
+	xw.WriteString(o.Name)
+	xw.WriteUint32(o.Flags)
+	xw.WriteUint64(uint64(o.Modified))
+	_, err := o.Version.EncodeXDRInto(xw)
+	if err != nil {
+		return xw.Tot(), err
+	}
+	xw.WriteUint64(uint64(o.LocalVersion))
+	if l := len(o.Blocks); l > 1000000 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Blocks", l, 1000000)
+	}
+	xw.WriteUint32(uint32(len(o.Blocks)))
+	for i := range o.Blocks {
+		_, err := o.Blocks[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	return xw.Tot(), xw.Error()
+}
+
+func (o *FileInfo) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *FileInfo) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *FileInfo) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.Name = xr.ReadStringMax(8192)
+	o.Flags = xr.ReadUint32()
+	o.Modified = int64(xr.ReadUint64())
+	(&o.Version).DecodeXDRFrom(xr)
+	o.LocalVersion = int64(xr.ReadUint64())
+	_BlocksSize := int(xr.ReadUint32())
+	if _BlocksSize < 0 {
+		return xdr.ElementSizeExceeded("Blocks", _BlocksSize, 1000000)
+	}
+	if _BlocksSize > 1000000 {
+		return xdr.ElementSizeExceeded("Blocks", _BlocksSize, 1000000)
+	}
+	o.Blocks = make([]BlockInfo, _BlocksSize)
+	for i := range o.Blocks {
+		(&o.Blocks[i]).DecodeXDRFrom(xr)
+	}
+	return xr.Error()
+}
+
+/*
+
+BlockInfo Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Size                              |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                        Length of Hash                         |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                    Hash (variable length)                     \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct BlockInfo {
+	int Size;
+	opaque Hash<64>;
+}
+
+*/
+
+func (o BlockInfo) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o BlockInfo) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o BlockInfo) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o BlockInfo) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o BlockInfo) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	xw.WriteUint32(uint32(o.Size))
+	if l := len(o.Hash); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Hash", l, 64)
+	}
+	xw.WriteBytes(o.Hash)
+	return xw.Tot(), xw.Error()
+}
+
+func (o *BlockInfo) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *BlockInfo) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *BlockInfo) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.Size = int32(xr.ReadUint32())
+	o.Hash = xr.ReadBytesMax(64)
+	return xr.Error()
+}
+
+/*
+
+RequestMessage Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Length of Folder                        |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                   Folder (variable length)                    \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                        Length of Name                         |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                    Name (variable length)                     \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                                                               |
++                       Offset (64 bits)                        +
+|                                                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Size                              |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                        Length of Hash                         |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                    Hash (variable length)                     \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Flags                             |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Options                       |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                Zero or more Option Structures                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct RequestMessage {
+	string Folder<64>;
+	string Name<8192>;
+	hyper Offset;
+	int Size;
+	opaque Hash<64>;
+	unsigned int Flags;
+	Option Options<64>;
+}
+
+*/
+
+func (o RequestMessage) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o RequestMessage) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o RequestMessage) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o RequestMessage) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o RequestMessage) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	if l := len(o.Folder); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Folder", l, 64)
+	}
+	xw.WriteString(o.Folder)
+	if l := len(o.Name); l > 8192 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Name", l, 8192)
+	}
+	xw.WriteString(o.Name)
+	xw.WriteUint64(uint64(o.Offset))
+	xw.WriteUint32(uint32(o.Size))
+	if l := len(o.Hash); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Hash", l, 64)
+	}
+	xw.WriteBytes(o.Hash)
+	xw.WriteUint32(o.Flags)
+	if l := len(o.Options); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Options", l, 64)
+	}
+	xw.WriteUint32(uint32(len(o.Options)))
+	for i := range o.Options {
+		_, err := o.Options[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	return xw.Tot(), xw.Error()
+}
+
+func (o *RequestMessage) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *RequestMessage) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *RequestMessage) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.Folder = xr.ReadStringMax(64)
+	o.Name = xr.ReadStringMax(8192)
+	o.Offset = int64(xr.ReadUint64())
+	o.Size = int32(xr.ReadUint32())
+	o.Hash = xr.ReadBytesMax(64)
+	o.Flags = xr.ReadUint32()
+	_OptionsSize := int(xr.ReadUint32())
+	if _OptionsSize < 0 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	if _OptionsSize > 64 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	o.Options = make([]Option, _OptionsSize)
+	for i := range o.Options {
+		(&o.Options[i]).DecodeXDRFrom(xr)
+	}
+	return xr.Error()
+}
+
+/*
+
+ResponseMessage Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                        Length of Data                         |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                    Data (variable length)                     \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Code                              |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct ResponseMessage {
+	opaque Data<>;
+	int Code;
+}
+
+*/
+
+func (o ResponseMessage) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o ResponseMessage) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o ResponseMessage) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o ResponseMessage) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o ResponseMessage) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	xw.WriteBytes(o.Data)
+	xw.WriteUint32(uint32(o.Code))
+	return xw.Tot(), xw.Error()
+}
+
+func (o *ResponseMessage) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *ResponseMessage) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *ResponseMessage) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.Data = xr.ReadBytes()
+	o.Code = int32(xr.ReadUint32())
+	return xr.Error()
+}
+
+/*
+
+ClusterConfigMessage Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                     Length of Client Name                     |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                 Client Name (variable length)                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                   Length of Client Version                    |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\               Client Version (variable length)                \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Folders                       |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                Zero or more Folder Structures                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Options                       |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                Zero or more Option Structures                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct ClusterConfigMessage {
+	string ClientName<64>;
+	string ClientVersion<64>;
+	Folder Folders<1000000>;
+	Option Options<64>;
+}
+
+*/
+
+func (o ClusterConfigMessage) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o ClusterConfigMessage) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o ClusterConfigMessage) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o ClusterConfigMessage) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o ClusterConfigMessage) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	if l := len(o.ClientName); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("ClientName", l, 64)
+	}
+	xw.WriteString(o.ClientName)
+	if l := len(o.ClientVersion); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("ClientVersion", l, 64)
+	}
+	xw.WriteString(o.ClientVersion)
+	if l := len(o.Folders); l > 1000000 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Folders", l, 1000000)
+	}
+	xw.WriteUint32(uint32(len(o.Folders)))
+	for i := range o.Folders {
+		_, err := o.Folders[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	if l := len(o.Options); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Options", l, 64)
+	}
+	xw.WriteUint32(uint32(len(o.Options)))
+	for i := range o.Options {
+		_, err := o.Options[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	return xw.Tot(), xw.Error()
+}
+
+func (o *ClusterConfigMessage) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *ClusterConfigMessage) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *ClusterConfigMessage) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.ClientName = xr.ReadStringMax(64)
+	o.ClientVersion = xr.ReadStringMax(64)
+	_FoldersSize := int(xr.ReadUint32())
+	if _FoldersSize < 0 {
+		return xdr.ElementSizeExceeded("Folders", _FoldersSize, 1000000)
+	}
+	if _FoldersSize > 1000000 {
+		return xdr.ElementSizeExceeded("Folders", _FoldersSize, 1000000)
+	}
+	o.Folders = make([]Folder, _FoldersSize)
+	for i := range o.Folders {
+		(&o.Folders[i]).DecodeXDRFrom(xr)
+	}
+	_OptionsSize := int(xr.ReadUint32())
+	if _OptionsSize < 0 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	if _OptionsSize > 64 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	o.Options = make([]Option, _OptionsSize)
+	for i := range o.Options {
+		(&o.Options[i]).DecodeXDRFrom(xr)
+	}
+	return xr.Error()
+}
+
+/*
+
+Folder Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                         Length of ID                          |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                     ID (variable length)                      \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Devices                       |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                Zero or more Device Structures                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Flags                             |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Options                       |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                Zero or more Option Structures                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct Folder {
+	string ID<64>;
+	Device Devices<1000000>;
+	unsigned int Flags;
+	Option Options<64>;
+}
+
+*/
+
+func (o Folder) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o Folder) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o Folder) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o Folder) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o Folder) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	if l := len(o.ID); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("ID", l, 64)
+	}
+	xw.WriteString(o.ID)
+	if l := len(o.Devices); l > 1000000 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Devices", l, 1000000)
+	}
+	xw.WriteUint32(uint32(len(o.Devices)))
+	for i := range o.Devices {
+		_, err := o.Devices[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	xw.WriteUint32(o.Flags)
+	if l := len(o.Options); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Options", l, 64)
+	}
+	xw.WriteUint32(uint32(len(o.Options)))
+	for i := range o.Options {
+		_, err := o.Options[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	return xw.Tot(), xw.Error()
+}
+
+func (o *Folder) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *Folder) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *Folder) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.ID = xr.ReadStringMax(64)
+	_DevicesSize := int(xr.ReadUint32())
+	if _DevicesSize < 0 {
+		return xdr.ElementSizeExceeded("Devices", _DevicesSize, 1000000)
+	}
+	if _DevicesSize > 1000000 {
+		return xdr.ElementSizeExceeded("Devices", _DevicesSize, 1000000)
+	}
+	o.Devices = make([]Device, _DevicesSize)
+	for i := range o.Devices {
+		(&o.Devices[i]).DecodeXDRFrom(xr)
+	}
+	o.Flags = xr.ReadUint32()
+	_OptionsSize := int(xr.ReadUint32())
+	if _OptionsSize < 0 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	if _OptionsSize > 64 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	o.Options = make([]Option, _OptionsSize)
+	for i := range o.Options {
+		(&o.Options[i]).DecodeXDRFrom(xr)
+	}
+	return xr.Error()
+}
+
+/*
+
+Device Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                         Length of ID                          |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                     ID (variable length)                      \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                                                               |
++                  Max Local Version (64 bits)                  +
+|                                                               |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Flags                             |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Number of Options                       |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                Zero or more Option Structures                 \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct Device {
+	opaque ID<32>;
+	hyper MaxLocalVersion;
+	unsigned int Flags;
+	Option Options<64>;
+}
+
+*/
+
+func (o Device) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o Device) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o Device) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o Device) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o Device) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	if l := len(o.ID); l > 32 {
+		return xw.Tot(), xdr.ElementSizeExceeded("ID", l, 32)
+	}
+	xw.WriteBytes(o.ID)
+	xw.WriteUint64(uint64(o.MaxLocalVersion))
+	xw.WriteUint32(o.Flags)
+	if l := len(o.Options); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Options", l, 64)
+	}
+	xw.WriteUint32(uint32(len(o.Options)))
+	for i := range o.Options {
+		_, err := o.Options[i].EncodeXDRInto(xw)
+		if err != nil {
+			return xw.Tot(), err
+		}
+	}
+	return xw.Tot(), xw.Error()
+}
+
+func (o *Device) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *Device) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *Device) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.ID = xr.ReadBytesMax(32)
+	o.MaxLocalVersion = int64(xr.ReadUint64())
+	o.Flags = xr.ReadUint32()
+	_OptionsSize := int(xr.ReadUint32())
+	if _OptionsSize < 0 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	if _OptionsSize > 64 {
+		return xdr.ElementSizeExceeded("Options", _OptionsSize, 64)
+	}
+	o.Options = make([]Option, _OptionsSize)
+	for i := range o.Options {
+		(&o.Options[i]).DecodeXDRFrom(xr)
+	}
+	return xr.Error()
+}
+
+/*
+
+Option Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                         Length of Key                         |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                     Key (variable length)                     \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                        Length of Value                        |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                    Value (variable length)                    \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct Option {
+	string Key<64>;
+	string Value<1024>;
+}
+
+*/
+
+func (o Option) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o Option) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o Option) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o Option) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o Option) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	if l := len(o.Key); l > 64 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Key", l, 64)
+	}
+	xw.WriteString(o.Key)
+	if l := len(o.Value); l > 1024 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Value", l, 1024)
+	}
+	xw.WriteString(o.Value)
+	return xw.Tot(), xw.Error()
+}
+
+func (o *Option) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *Option) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *Option) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.Key = xr.ReadStringMax(64)
+	o.Value = xr.ReadStringMax(1024)
+	return xr.Error()
+}
+
+/*
+
+CloseMessage Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                       Length of Reason                        |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+/                                                               /
+\                   Reason (variable length)                    \
+/                                                               /
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|                             Code                              |
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct CloseMessage {
+	string Reason<1024>;
+	int Code;
+}
+
+*/
+
+func (o CloseMessage) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o CloseMessage) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o CloseMessage) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o CloseMessage) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o CloseMessage) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	if l := len(o.Reason); l > 1024 {
+		return xw.Tot(), xdr.ElementSizeExceeded("Reason", l, 1024)
+	}
+	xw.WriteString(o.Reason)
+	xw.WriteUint32(uint32(o.Code))
+	return xw.Tot(), xw.Error()
+}
+
+func (o *CloseMessage) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *CloseMessage) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *CloseMessage) DecodeXDRFrom(xr *xdr.Reader) error {
+	o.Reason = xr.ReadStringMax(1024)
+	o.Code = int32(xr.ReadUint32())
+	return xr.Error()
+}
+
+/*
+
+EmptyMessage Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct EmptyMessage {
+}
+
+*/
+
+func (o EmptyMessage) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o EmptyMessage) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o EmptyMessage) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o EmptyMessage) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o EmptyMessage) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	return xw.Tot(), xw.Error()
+}
+
+func (o *EmptyMessage) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *EmptyMessage) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *EmptyMessage) DecodeXDRFrom(xr *xdr.Reader) error {
+	return xr.Error()
+}

lib/protocol/nativemodel_darwin.go

@@ -0,0 +1,40 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+// +build darwin
+
+package protocol
+
+// Darwin uses NFD normalization
+
+import "golang.org/x/text/unicode/norm"
+
+type nativeModel struct {
+	next Model
+}
+
+func (m nativeModel) Index(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+	for i := range files {
+		files[i].Name = norm.NFD.String(files[i].Name)
+	}
+	m.next.Index(deviceID, folder, files, flags, options)
+}
+
+func (m nativeModel) IndexUpdate(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+	for i := range files {
+		files[i].Name = norm.NFD.String(files[i].Name)
+	}
+	m.next.IndexUpdate(deviceID, folder, files, flags, options)
+}
+
+func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error {
+	name = norm.NFD.String(name)
+	return m.next.Request(deviceID, folder, name, offset, hash, flags, options, buf)
+}
+
+func (m nativeModel) ClusterConfig(deviceID DeviceID, config ClusterConfigMessage) {
+	m.next.ClusterConfig(deviceID, config)
+}
+
+func (m nativeModel) Close(deviceID DeviceID, err error) {
+	m.next.Close(deviceID, err)
+}

lib/protocol/nativemodel_unix.go

@@ -0,0 +1,31 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+// +build !windows,!darwin
+
+package protocol
+
+// Normal Unixes uses NFC and slashes, which is the wire format.
+
+type nativeModel struct {
+	next Model
+}
+
+func (m nativeModel) Index(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+	m.next.Index(deviceID, folder, files, flags, options)
+}
+
+func (m nativeModel) IndexUpdate(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+	m.next.IndexUpdate(deviceID, folder, files, flags, options)
+}
+
+func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error {
+	return m.next.Request(deviceID, folder, name, offset, hash, flags, options, buf)
+}
+
+func (m nativeModel) ClusterConfig(deviceID DeviceID, config ClusterConfigMessage) {
+	m.next.ClusterConfig(deviceID, config)
+}
+
+func (m nativeModel) Close(deviceID DeviceID, err error) {
+	m.next.Close(deviceID, err)
+}

lib/protocol/nativemodel_windows.go

@@ -0,0 +1,63 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+// +build windows
+
+package protocol
+
+// Windows uses backslashes as file separator and disallows a bunch of
+// characters in the filename
+
+import (
+	"path/filepath"
+	"strings"
+)
+
+var disallowedCharacters = string([]rune{
+	'<', '>', ':', '"', '|', '?', '*',
+	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+	11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
+	21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
+	31,
+})
+
+type nativeModel struct {
+	next Model
+}
+
+func (m nativeModel) Index(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+	fixupFiles(folder, files)
+	m.next.Index(deviceID, folder, files, flags, options)
+}
+
+func (m nativeModel) IndexUpdate(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option) {
+	fixupFiles(folder, files)
+	m.next.IndexUpdate(deviceID, folder, files, flags, options)
+}
+
+func (m nativeModel) Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error {
+	name = filepath.FromSlash(name)
+	return m.next.Request(deviceID, folder, name, offset, hash, flags, options, buf)
+}
+
+func (m nativeModel) ClusterConfig(deviceID DeviceID, config ClusterConfigMessage) {
+	m.next.ClusterConfig(deviceID, config)
+}
+
+func (m nativeModel) Close(deviceID DeviceID, err error) {
+	m.next.Close(deviceID, err)
+}
+
+func fixupFiles(folder string, files []FileInfo) {
+	for i, f := range files {
+		if strings.ContainsAny(f.Name, disallowedCharacters) {
+			if f.IsDeleted() {
+				// Don't complain if the file is marked as deleted, since it
+				// can't possibly exist here anyway.
+				continue
+			}
+			files[i].Flags |= FlagInvalid
+			l.Warnf("File name %q (folder %q) contains invalid characters; marked as invalid.", f.Name, folder)
+		}
+		files[i].Name = filepath.FromSlash(files[i].Name)
+	}
+}

lib/protocol/protocol.go

@@ -0,0 +1,782 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"sync"
+	"time"
+
+	lz4 "github.com/bkaradzic/go-lz4"
+)
+
+const (
+	// Data block size (128 KiB)
+	BlockSize = 128 << 10
+
+	// We reject messages larger than this when encountered on the wire. (64 MiB)
+	MaxMessageLen = 64 << 20
+)
+
+const (
+	messageTypeClusterConfig = 0
+	messageTypeIndex         = 1
+	messageTypeRequest       = 2
+	messageTypeResponse      = 3
+	messageTypePing          = 4
+	messageTypeIndexUpdate   = 6
+	messageTypeClose         = 7
+)
+
+const (
+	stateInitial = iota
+	stateReady
+)
+
+// FileInfo flags
+const (
+	FlagDeleted              uint32 = 1 << 12
+	FlagInvalid                     = 1 << 13
+	FlagDirectory                   = 1 << 14
+	FlagNoPermBits                  = 1 << 15
+	FlagSymlink                     = 1 << 16
+	FlagSymlinkMissingTarget        = 1 << 17
+
+	FlagsAll = (1 << 18) - 1
+
+	SymlinkTypeMask = FlagDirectory | FlagSymlinkMissingTarget
+)
+
+// IndexMessage message flags (for IndexUpdate)
+const (
+	FlagIndexTemporary uint32 = 1 << iota
+)
+
+// Request message flags
+const (
+	FlagRequestTemporary uint32 = 1 << iota
+)
+
+// ClusterConfigMessage.Folders.Devices flags
+const (
+	FlagShareTrusted  uint32 = 1 << 0
+	FlagShareReadOnly        = 1 << 1
+	FlagIntroducer           = 1 << 2
+	FlagShareBits            = 0x000000ff
+)
+
+var (
+	ErrClosed  = errors.New("connection closed")
+	ErrTimeout = errors.New("read timeout")
+)
+
+// Specific variants of empty messages...
+type pingMessage struct{ EmptyMessage }
+
+type Model interface {
+	// An index was received from the peer device
+	Index(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option)
+	// An index update was received from the peer device
+	IndexUpdate(deviceID DeviceID, folder string, files []FileInfo, flags uint32, options []Option)
+	// A request was made by the peer device
+	Request(deviceID DeviceID, folder string, name string, offset int64, hash []byte, flags uint32, options []Option, buf []byte) error
+	// A cluster configuration message was received
+	ClusterConfig(deviceID DeviceID, config ClusterConfigMessage)
+	// The peer device closed the connection
+	Close(deviceID DeviceID, err error)
+}
+
+type Connection interface {
+	Start()
+	ID() DeviceID
+	Name() string
+	Index(folder string, files []FileInfo, flags uint32, options []Option) error
+	IndexUpdate(folder string, files []FileInfo, flags uint32, options []Option) error
+	Request(folder string, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error)
+	ClusterConfig(config ClusterConfigMessage)
+	Statistics() Statistics
+}
+
+type rawConnection struct {
+	id       DeviceID
+	name     string
+	receiver Model
+
+	cr *countingReader
+	cw *countingWriter
+
+	awaiting    [4096]chan asyncResult
+	awaitingMut sync.Mutex
+
+	idxMut sync.Mutex // ensures serialization of Index calls
+
+	nextID      chan int
+	outbox      chan hdrMsg
+	closed      chan struct{}
+	once        sync.Once
+	pool        sync.Pool
+	compression Compression
+
+	rdbuf0 []byte // used & reused by readMessage
+	rdbuf1 []byte // used & reused by readMessage
+}
+
+type asyncResult struct {
+	val []byte
+	err error
+}
+
+type hdrMsg struct {
+	hdr  header
+	msg  encodable
+	done chan struct{}
+}
+
+type encodable interface {
+	AppendXDR([]byte) ([]byte, error)
+}
+
+type isEofer interface {
+	IsEOF() bool
+}
+
+const (
+	// We make sure to send a message at least this often, by triggering pings.
+	PingSendInterval = 90 * time.Second
+	// If we haven't received a message from the other side for this long, close the connection.
+	ReceiveTimeout = 300 * time.Second
+)
+
+func NewConnection(deviceID DeviceID, reader io.Reader, writer io.Writer, receiver Model, name string, compress Compression) Connection {
+	cr := &countingReader{Reader: reader}
+	cw := &countingWriter{Writer: writer}
+
+	c := rawConnection{
+		id:       deviceID,
+		name:     name,
+		receiver: nativeModel{receiver},
+		cr:       cr,
+		cw:       cw,
+		outbox:   make(chan hdrMsg),
+		nextID:   make(chan int),
+		closed:   make(chan struct{}),
+		pool: sync.Pool{
+			New: func() interface{} {
+				return make([]byte, BlockSize)
+			},
+		},
+		compression: compress,
+	}
+
+	return wireFormatConnection{&c}
+}
+
+// Start creates the goroutines for sending and receiving of messages. It must
+// be called exactly once after creating a connection.
+func (c *rawConnection) Start() {
+	go c.readerLoop()
+	go c.writerLoop()
+	go c.pingSender()
+	go c.pingReceiver()
+	go c.idGenerator()
+}
+
+func (c *rawConnection) ID() DeviceID {
+	return c.id
+}
+
+func (c *rawConnection) Name() string {
+	return c.name
+}
+
+// Index writes the list of file information to the connected peer device
+func (c *rawConnection) Index(folder string, idx []FileInfo, flags uint32, options []Option) error {
+	select {
+	case <-c.closed:
+		return ErrClosed
+	default:
+	}
+	c.idxMut.Lock()
+	c.send(-1, messageTypeIndex, IndexMessage{
+		Folder:  folder,
+		Files:   idx,
+		Flags:   flags,
+		Options: options,
+	}, nil)
+	c.idxMut.Unlock()
+	return nil
+}
+
+// IndexUpdate writes the list of file information to the connected peer device as an update
+func (c *rawConnection) IndexUpdate(folder string, idx []FileInfo, flags uint32, options []Option) error {
+	select {
+	case <-c.closed:
+		return ErrClosed
+	default:
+	}
+	c.idxMut.Lock()
+	c.send(-1, messageTypeIndexUpdate, IndexMessage{
+		Folder:  folder,
+		Files:   idx,
+		Flags:   flags,
+		Options: options,
+	}, nil)
+	c.idxMut.Unlock()
+	return nil
+}
+
+// Request returns the bytes for the specified block after fetching them from the connected peer.
+func (c *rawConnection) Request(folder string, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error) {
+	var id int
+	select {
+	case id = <-c.nextID:
+	case <-c.closed:
+		return nil, ErrClosed
+	}
+
+	c.awaitingMut.Lock()
+	if ch := c.awaiting[id]; ch != nil {
+		panic("id taken")
+	}
+	rc := make(chan asyncResult, 1)
+	c.awaiting[id] = rc
+	c.awaitingMut.Unlock()
+
+	ok := c.send(id, messageTypeRequest, RequestMessage{
+		Folder:  folder,
+		Name:    name,
+		Offset:  offset,
+		Size:    int32(size),
+		Hash:    hash,
+		Flags:   flags,
+		Options: options,
+	}, nil)
+	if !ok {
+		return nil, ErrClosed
+	}
+
+	res, ok := <-rc
+	if !ok {
+		return nil, ErrClosed
+	}
+	return res.val, res.err
+}
+
+// ClusterConfig send the cluster configuration message to the peer and returns any error
+func (c *rawConnection) ClusterConfig(config ClusterConfigMessage) {
+	c.send(-1, messageTypeClusterConfig, config, nil)
+}
+
+func (c *rawConnection) ping() bool {
+	var id int
+	select {
+	case id = <-c.nextID:
+	case <-c.closed:
+		return false
+	}
+
+	return c.send(id, messageTypePing, nil, nil)
+}
+
+func (c *rawConnection) readerLoop() (err error) {
+	defer func() {
+		c.close(err)
+	}()
+
+	state := stateInitial
+	for {
+		select {
+		case <-c.closed:
+			return ErrClosed
+		default:
+		}
+
+		hdr, msg, err := c.readMessage()
+		if err != nil {
+			return err
+		}
+
+		switch msg := msg.(type) {
+		case ClusterConfigMessage:
+			if state != stateInitial {
+				return fmt.Errorf("protocol error: cluster config message in state %d", state)
+			}
+			go c.receiver.ClusterConfig(c.id, msg)
+			state = stateReady
+
+		case IndexMessage:
+			switch hdr.msgType {
+			case messageTypeIndex:
+				if state != stateReady {
+					return fmt.Errorf("protocol error: index message in state %d", state)
+				}
+				c.handleIndex(msg)
+				state = stateReady
+
+			case messageTypeIndexUpdate:
+				if state != stateReady {
+					return fmt.Errorf("protocol error: index update message in state %d", state)
+				}
+				c.handleIndexUpdate(msg)
+				state = stateReady
+			}
+
+		case RequestMessage:
+			if state != stateReady {
+				return fmt.Errorf("protocol error: request message in state %d", state)
+			}
+			// Requests are handled asynchronously
+			go c.handleRequest(hdr.msgID, msg)
+
+		case ResponseMessage:
+			if state != stateReady {
+				return fmt.Errorf("protocol error: response message in state %d", state)
+			}
+			c.handleResponse(hdr.msgID, msg)
+
+		case pingMessage:
+			if state != stateReady {
+				return fmt.Errorf("protocol error: ping message in state %d", state)
+			}
+			// Nothing
+
+		case CloseMessage:
+			return errors.New(msg.Reason)
+
+		default:
+			return fmt.Errorf("protocol error: %s: unknown message type %#x", c.id, hdr.msgType)
+		}
+	}
+}
+
+func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
+	if cap(c.rdbuf0) < 8 {
+		c.rdbuf0 = make([]byte, 8)
+	} else {
+		c.rdbuf0 = c.rdbuf0[:8]
+	}
+	_, err = io.ReadFull(c.cr, c.rdbuf0)
+	if err != nil {
+		return
+	}
+
+	hdr = decodeHeader(binary.BigEndian.Uint32(c.rdbuf0[0:4]))
+	msglen := int(binary.BigEndian.Uint32(c.rdbuf0[4:8]))
+
+	if debug {
+		l.Debugf("read header %v (msglen=%d)", hdr, msglen)
+	}
+
+	if msglen > MaxMessageLen {
+		err = fmt.Errorf("message length %d exceeds maximum %d", msglen, MaxMessageLen)
+		return
+	}
+
+	if hdr.version != 0 {
+		err = fmt.Errorf("unknown protocol version 0x%x", hdr.version)
+		return
+	}
+
+	if cap(c.rdbuf0) < msglen {
+		c.rdbuf0 = make([]byte, msglen)
+	} else {
+		c.rdbuf0 = c.rdbuf0[:msglen]
+	}
+	_, err = io.ReadFull(c.cr, c.rdbuf0)
+	if err != nil {
+		return
+	}
+
+	if debug {
+		l.Debugf("read %d bytes", len(c.rdbuf0))
+	}
+
+	msgBuf := c.rdbuf0
+	if hdr.compression && msglen > 0 {
+		c.rdbuf1 = c.rdbuf1[:cap(c.rdbuf1)]
+		c.rdbuf1, err = lz4.Decode(c.rdbuf1, c.rdbuf0)
+		if err != nil {
+			return
+		}
+		msgBuf = c.rdbuf1
+		if debug {
+			l.Debugf("decompressed to %d bytes", len(msgBuf))
+		}
+	}
+
+	if debug {
+		if len(msgBuf) > 1024 {
+			l.Debugf("message data:\n%s", hex.Dump(msgBuf[:1024]))
+		} else {
+			l.Debugf("message data:\n%s", hex.Dump(msgBuf))
+		}
+	}
+
+	// We check each returned error for the XDRError.IsEOF() method.
+	// IsEOF()==true here means that the message contained fewer fields than
+	// expected. It does not signify an EOF on the socket, because we've
+	// successfully read a size value and that many bytes already. New fields
+	// we expected but the other peer didn't send should be interpreted as
+	// zero/nil, and if that's not valid we'll verify it somewhere else.
+
+	switch hdr.msgType {
+	case messageTypeIndex, messageTypeIndexUpdate:
+		var idx IndexMessage
+		err = idx.UnmarshalXDR(msgBuf)
+		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
+			err = nil
+		}
+		msg = idx
+
+	case messageTypeRequest:
+		var req RequestMessage
+		err = req.UnmarshalXDR(msgBuf)
+		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
+			err = nil
+		}
+		msg = req
+
+	case messageTypeResponse:
+		var resp ResponseMessage
+		err = resp.UnmarshalXDR(msgBuf)
+		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
+			err = nil
+		}
+		msg = resp
+
+	case messageTypePing:
+		msg = pingMessage{}
+
+	case messageTypeClusterConfig:
+		var cc ClusterConfigMessage
+		err = cc.UnmarshalXDR(msgBuf)
+		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
+			err = nil
+		}
+		msg = cc
+
+	case messageTypeClose:
+		var cm CloseMessage
+		err = cm.UnmarshalXDR(msgBuf)
+		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
+			err = nil
+		}
+		msg = cm
+
+	default:
+		err = fmt.Errorf("protocol error: %s: unknown message type %#x", c.id, hdr.msgType)
+	}
+
+	return
+}
+
+func (c *rawConnection) handleIndex(im IndexMessage) {
+	if debug {
+		l.Debugf("Index(%v, %v, %d file, flags %x, opts: %s)", c.id, im.Folder, len(im.Files), im.Flags, im.Options)
+	}
+	c.receiver.Index(c.id, im.Folder, filterIndexMessageFiles(im.Files), im.Flags, im.Options)
+}
+
+func (c *rawConnection) handleIndexUpdate(im IndexMessage) {
+	if debug {
+		l.Debugf("queueing IndexUpdate(%v, %v, %d files, flags %x, opts: %s)", c.id, im.Folder, len(im.Files), im.Flags, im.Options)
+	}
+	c.receiver.IndexUpdate(c.id, im.Folder, filterIndexMessageFiles(im.Files), im.Flags, im.Options)
+}
+
+func filterIndexMessageFiles(fs []FileInfo) []FileInfo {
+	var out []FileInfo
+	for i, f := range fs {
+		switch f.Name {
+		case "", ".", "..", "/": // A few obviously invalid filenames
+			l.Infof("Dropping invalid filename %q from incoming index", f.Name)
+			if out == nil {
+				// Most incoming updates won't contain anything invalid, so we
+				// delay the allocation and copy to output slice until we
+				// really need to do it, then copy all the so var valid files
+				// to it.
+				out = make([]FileInfo, i, len(fs)-1)
+				copy(out, fs)
+			}
+		default:
+			if out != nil {
+				out = append(out, f)
+			}
+		}
+	}
+	if out != nil {
+		return out
+	}
+	return fs
+}
+
+func (c *rawConnection) handleRequest(msgID int, req RequestMessage) {
+	size := int(req.Size)
+	usePool := size <= BlockSize
+
+	var buf []byte
+	var done chan struct{}
+
+	if usePool {
+		buf = c.pool.Get().([]byte)[:size]
+		done = make(chan struct{})
+	} else {
+		buf = make([]byte, size)
+	}
+
+	err := c.receiver.Request(c.id, req.Folder, req.Name, int64(req.Offset), req.Hash, req.Flags, req.Options, buf)
+	if err != nil {
+		c.send(msgID, messageTypeResponse, ResponseMessage{
+			Data: nil,
+			Code: errorToCode(err),
+		}, done)
+	} else {
+		c.send(msgID, messageTypeResponse, ResponseMessage{
+			Data: buf,
+			Code: errorToCode(err),
+		}, done)
+	}
+
+	if usePool {
+		<-done
+		c.pool.Put(buf)
+	}
+}
+
+func (c *rawConnection) handleResponse(msgID int, resp ResponseMessage) {
+	c.awaitingMut.Lock()
+	if rc := c.awaiting[msgID]; rc != nil {
+		c.awaiting[msgID] = nil
+		rc <- asyncResult{resp.Data, codeToError(resp.Code)}
+		close(rc)
+	}
+	c.awaitingMut.Unlock()
+}
+
+func (c *rawConnection) handlePong(msgID int) {
+	c.awaitingMut.Lock()
+	if rc := c.awaiting[msgID]; rc != nil {
+		c.awaiting[msgID] = nil
+		rc <- asyncResult{}
+		close(rc)
+	}
+	c.awaitingMut.Unlock()
+}
+
+func (c *rawConnection) send(msgID int, msgType int, msg encodable, done chan struct{}) bool {
+	if msgID < 0 {
+		select {
+		case id := <-c.nextID:
+			msgID = id
+		case <-c.closed:
+			return false
+		}
+	}
+
+	hdr := header{
+		version: 0,
+		msgID:   msgID,
+		msgType: msgType,
+	}
+
+	select {
+	case c.outbox <- hdrMsg{hdr, msg, done}:
+		return true
+	case <-c.closed:
+		return false
+	}
+}
+
+func (c *rawConnection) writerLoop() {
+	var msgBuf = make([]byte, 8) // buffer for wire format message, kept and reused
+	var uncBuf []byte            // buffer for uncompressed message, kept and reused
+	for {
+		var tempBuf []byte
+		var err error
+
+		select {
+		case hm := <-c.outbox:
+			if hm.msg != nil {
+				// Uncompressed message in uncBuf
+				uncBuf, err = hm.msg.AppendXDR(uncBuf[:0])
+				if hm.done != nil {
+					close(hm.done)
+				}
+				if err != nil {
+					c.close(err)
+					return
+				}
+
+				compress := false
+				switch c.compression {
+				case CompressAlways:
+					compress = true
+				case CompressMetadata:
+					compress = hm.hdr.msgType != messageTypeResponse
+				}
+
+				if compress && len(uncBuf) >= compressionThreshold {
+					// Use compression for large messages
+					hm.hdr.compression = true
+
+					// Make sure we have enough space for the compressed message plus header in msgBug
+					msgBuf = msgBuf[:cap(msgBuf)]
+					if maxLen := lz4.CompressBound(len(uncBuf)) + 8; maxLen > len(msgBuf) {
+						msgBuf = make([]byte, maxLen)
+					}
+
+					// Compressed is written to msgBuf, we keep tb for the length only
+					tempBuf, err = lz4.Encode(msgBuf[8:], uncBuf)
+					binary.BigEndian.PutUint32(msgBuf[4:8], uint32(len(tempBuf)))
+					msgBuf = msgBuf[0 : len(tempBuf)+8]
+
+					if debug {
+						l.Debugf("write compressed message; %v (len=%d)", hm.hdr, len(tempBuf))
+					}
+				} else {
+					// No point in compressing very short messages
+					hm.hdr.compression = false
+
+					msgBuf = msgBuf[:cap(msgBuf)]
+					if l := len(uncBuf) + 8; l > len(msgBuf) {
+						msgBuf = make([]byte, l)
+					}
+
+					binary.BigEndian.PutUint32(msgBuf[4:8], uint32(len(uncBuf)))
+					msgBuf = msgBuf[0 : len(uncBuf)+8]
+					copy(msgBuf[8:], uncBuf)
+
+					if debug {
+						l.Debugf("write uncompressed message; %v (len=%d)", hm.hdr, len(uncBuf))
+					}
+				}
+			} else {
+				if debug {
+					l.Debugf("write empty message; %v", hm.hdr)
+				}
+				binary.BigEndian.PutUint32(msgBuf[4:8], 0)
+				msgBuf = msgBuf[:8]
+			}
+
+			binary.BigEndian.PutUint32(msgBuf[0:4], encodeHeader(hm.hdr))
+
+			if err == nil {
+				var n int
+				n, err = c.cw.Write(msgBuf)
+				if debug {
+					l.Debugf("wrote %d bytes on the wire", n)
+				}
+			}
+			if err != nil {
+				c.close(err)
+				return
+			}
+		case <-c.closed:
+			return
+		}
+	}
+}
+
+func (c *rawConnection) close(err error) {
+	c.once.Do(func() {
+		close(c.closed)
+
+		c.awaitingMut.Lock()
+		for i, ch := range c.awaiting {
+			if ch != nil {
+				close(ch)
+				c.awaiting[i] = nil
+			}
+		}
+		c.awaitingMut.Unlock()
+
+		go c.receiver.Close(c.id, err)
+	})
+}
+
+func (c *rawConnection) idGenerator() {
+	nextID := 0
+	for {
+		nextID = (nextID + 1) & 0xfff
+		select {
+		case c.nextID <- nextID:
+		case <-c.closed:
+			return
+		}
+	}
+}
+
+// The pingSender makes sure that we've sent a message within the last
+// PingSendInterval. If we already have something sent in the last
+// PingSendInterval/2, we do nothing. Otherwise we send a ping message. This
+// results in an effecting ping interval of somewhere between
+// PingSendInterval/2 and PingSendInterval.
+func (c *rawConnection) pingSender() {
+	ticker := time.Tick(PingSendInterval / 2)
+
+	for {
+		select {
+		case <-ticker:
+			d := time.Since(c.cw.Last())
+			if d < PingSendInterval/2 {
+				if debug {
+					l.Debugln(c.id, "ping skipped after wr", d)
+				}
+				continue
+			}
+
+			if debug {
+				l.Debugln(c.id, "ping -> after", d)
+			}
+			c.ping()
+
+		case <-c.closed:
+			return
+		}
+	}
+}
+
+// The pingReciever checks that we've received a message (any message will do,
+// but we expect pings in the absence of other messages) within the last
+// ReceiveTimeout. If not, we close the connection with an ErrTimeout.
+func (c *rawConnection) pingReceiver() {
+	ticker := time.Tick(ReceiveTimeout / 2)
+
+	for {
+		select {
+		case <-ticker:
+			d := time.Since(c.cr.Last())
+			if d > ReceiveTimeout {
+				if debug {
+					l.Debugln(c.id, "ping timeout", d)
+				}
+				c.close(ErrTimeout)
+			}
+
+			if debug {
+				l.Debugln(c.id, "last read within", d)
+			}
+
+		case <-c.closed:
+			return
+		}
+	}
+}
+
+type Statistics struct {
+	At            time.Time
+	InBytesTotal  int64
+	OutBytesTotal int64
+}
+
+func (c *rawConnection) Statistics() Statistics {
+	return Statistics{
+		At:            time.Now(),
+		InBytesTotal:  c.cr.Tot(),
+		OutBytesTotal: c.cw.Tot(),
+	}
+}

lib/protocol/protocol_test.go

@@ -0,0 +1,316 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+	"testing/quick"
+
+	"github.com/calmh/xdr"
+)
+
+var (
+	c0ID = NewDeviceID([]byte{1})
+	c1ID = NewDeviceID([]byte{2})
+)
+
+func TestHeaderFunctions(t *testing.T) {
+	f := func(ver, id, typ int) bool {
+		ver = int(uint(ver) % 16)
+		id = int(uint(id) % 4096)
+		typ = int(uint(typ) % 256)
+		h0 := header{version: ver, msgID: id, msgType: typ}
+		h1 := decodeHeader(encodeHeader(h0))
+		return h0 == h1
+	}
+	if err := quick.Check(f, nil); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestHeaderLayout(t *testing.T) {
+	var e, a uint32
+
+	// Version are the first four bits
+	e = 0xf0000000
+	a = encodeHeader(header{version: 0xf})
+	if a != e {
+		t.Errorf("Header layout incorrect; %08x != %08x", a, e)
+	}
+
+	// Message ID are the following 12 bits
+	e = 0x0fff0000
+	a = encodeHeader(header{msgID: 0xfff})
+	if a != e {
+		t.Errorf("Header layout incorrect; %08x != %08x", a, e)
+	}
+
+	// Type are the last 8 bits before reserved
+	e = 0x0000ff00
+	a = encodeHeader(header{msgType: 0xff})
+	if a != e {
+		t.Errorf("Header layout incorrect; %08x != %08x", a, e)
+	}
+}
+
+func TestPing(t *testing.T) {
+	ar, aw := io.Pipe()
+	br, bw := io.Pipe()
+
+	c0 := NewConnection(c0ID, ar, bw, newTestModel(), "name", CompressAlways).(wireFormatConnection).next.(*rawConnection)
+	c0.Start()
+	c1 := NewConnection(c1ID, br, aw, newTestModel(), "name", CompressAlways).(wireFormatConnection).next.(*rawConnection)
+	c1.Start()
+	c0.ClusterConfig(ClusterConfigMessage{})
+	c1.ClusterConfig(ClusterConfigMessage{})
+
+	if ok := c0.ping(); !ok {
+		t.Error("c0 ping failed")
+	}
+	if ok := c1.ping(); !ok {
+		t.Error("c1 ping failed")
+	}
+}
+
+func TestVersionErr(t *testing.T) {
+	m0 := newTestModel()
+	m1 := newTestModel()
+
+	ar, aw := io.Pipe()
+	br, bw := io.Pipe()
+
+	c0 := NewConnection(c0ID, ar, bw, m0, "name", CompressAlways).(wireFormatConnection).next.(*rawConnection)
+	c0.Start()
+	c1 := NewConnection(c1ID, br, aw, m1, "name", CompressAlways)
+	c1.Start()
+	c0.ClusterConfig(ClusterConfigMessage{})
+	c1.ClusterConfig(ClusterConfigMessage{})
+
+	w := xdr.NewWriter(c0.cw)
+	w.WriteUint32(encodeHeader(header{
+		version: 2,
+		msgID:   0,
+		msgType: 0,
+	}))
+	w.WriteUint32(0) // Avoids reader closing due to EOF
+
+	if !m1.isClosed() {
+		t.Error("Connection should close due to unknown version")
+	}
+}
+
+func TestTypeErr(t *testing.T) {
+	m0 := newTestModel()
+	m1 := newTestModel()
+
+	ar, aw := io.Pipe()
+	br, bw := io.Pipe()
+
+	c0 := NewConnection(c0ID, ar, bw, m0, "name", CompressAlways).(wireFormatConnection).next.(*rawConnection)
+	c0.Start()
+	c1 := NewConnection(c1ID, br, aw, m1, "name", CompressAlways)
+	c1.Start()
+	c0.ClusterConfig(ClusterConfigMessage{})
+	c1.ClusterConfig(ClusterConfigMessage{})
+
+	w := xdr.NewWriter(c0.cw)
+	w.WriteUint32(encodeHeader(header{
+		version: 0,
+		msgID:   0,
+		msgType: 42,
+	}))
+	w.WriteUint32(0) // Avoids reader closing due to EOF
+
+	if !m1.isClosed() {
+		t.Error("Connection should close due to unknown message type")
+	}
+}
+
+func TestClose(t *testing.T) {
+	m0 := newTestModel()
+	m1 := newTestModel()
+
+	ar, aw := io.Pipe()
+	br, bw := io.Pipe()
+
+	c0 := NewConnection(c0ID, ar, bw, m0, "name", CompressAlways).(wireFormatConnection).next.(*rawConnection)
+	c0.Start()
+	c1 := NewConnection(c1ID, br, aw, m1, "name", CompressAlways)
+	c1.Start()
+	c0.ClusterConfig(ClusterConfigMessage{})
+	c1.ClusterConfig(ClusterConfigMessage{})
+
+	c0.close(nil)
+
+	<-c0.closed
+	if !m0.isClosed() {
+		t.Fatal("Connection should be closed")
+	}
+
+	// None of these should panic, some should return an error
+
+	if c0.ping() {
+		t.Error("Ping should not return true")
+	}
+
+	c0.Index("default", nil, 0, nil)
+	c0.Index("default", nil, 0, nil)
+
+	if _, err := c0.Request("default", "foo", 0, 0, nil, 0, nil); err == nil {
+		t.Error("Request should return an error")
+	}
+}
+
+func TestElementSizeExceededNested(t *testing.T) {
+	m := ClusterConfigMessage{
+		Folders: []Folder{
+			{ID: "longstringlongstringlongstringinglongstringlongstringlonlongstringlongstringlon"},
+		},
+	}
+	_, err := m.EncodeXDR(ioutil.Discard)
+	if err == nil {
+		t.Errorf("ID length %d > max 64, but no error", len(m.Folders[0].ID))
+	}
+}
+
+func TestMarshalIndexMessage(t *testing.T) {
+	var quickCfg = &quick.Config{MaxCountScale: 10}
+	if testing.Short() {
+		quickCfg = nil
+	}
+
+	f := func(m1 IndexMessage) bool {
+		for i, f := range m1.Files {
+			m1.Files[i].CachedSize = 0
+			for j := range f.Blocks {
+				f.Blocks[j].Offset = 0
+				if len(f.Blocks[j].Hash) == 0 {
+					f.Blocks[j].Hash = nil
+				}
+			}
+		}
+
+		return testMarshal(t, "index", &m1, &IndexMessage{})
+	}
+
+	if err := quick.Check(f, quickCfg); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestMarshalRequestMessage(t *testing.T) {
+	var quickCfg = &quick.Config{MaxCountScale: 10}
+	if testing.Short() {
+		quickCfg = nil
+	}
+
+	f := func(m1 RequestMessage) bool {
+		return testMarshal(t, "request", &m1, &RequestMessage{})
+	}
+
+	if err := quick.Check(f, quickCfg); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestMarshalResponseMessage(t *testing.T) {
+	var quickCfg = &quick.Config{MaxCountScale: 10}
+	if testing.Short() {
+		quickCfg = nil
+	}
+
+	f := func(m1 ResponseMessage) bool {
+		if len(m1.Data) == 0 {
+			m1.Data = nil
+		}
+		return testMarshal(t, "response", &m1, &ResponseMessage{})
+	}
+
+	if err := quick.Check(f, quickCfg); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestMarshalClusterConfigMessage(t *testing.T) {
+	var quickCfg = &quick.Config{MaxCountScale: 10}
+	if testing.Short() {
+		quickCfg = nil
+	}
+
+	f := func(m1 ClusterConfigMessage) bool {
+		return testMarshal(t, "clusterconfig", &m1, &ClusterConfigMessage{})
+	}
+
+	if err := quick.Check(f, quickCfg); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestMarshalCloseMessage(t *testing.T) {
+	var quickCfg = &quick.Config{MaxCountScale: 10}
+	if testing.Short() {
+		quickCfg = nil
+	}
+
+	f := func(m1 CloseMessage) bool {
+		return testMarshal(t, "close", &m1, &CloseMessage{})
+	}
+
+	if err := quick.Check(f, quickCfg); err != nil {
+		t.Error(err)
+	}
+}
+
+type message interface {
+	EncodeXDR(io.Writer) (int, error)
+	DecodeXDR(io.Reader) error
+}
+
+func testMarshal(t *testing.T, prefix string, m1, m2 message) bool {
+	var buf bytes.Buffer
+
+	failed := func(bc []byte) {
+		bs, _ := json.MarshalIndent(m1, "", "  ")
+		ioutil.WriteFile(prefix+"-1.txt", bs, 0644)
+		bs, _ = json.MarshalIndent(m2, "", "  ")
+		ioutil.WriteFile(prefix+"-2.txt", bs, 0644)
+		if len(bc) > 0 {
+			f, _ := os.Create(prefix + "-data.txt")
+			fmt.Fprint(f, hex.Dump(bc))
+			f.Close()
+		}
+	}
+
+	_, err := m1.EncodeXDR(&buf)
+	if err != nil && strings.Contains(err.Error(), "exceeds size") {
+		return true
+	}
+	if err != nil {
+		failed(nil)
+		t.Fatal(err)
+	}
+
+	bc := make([]byte, len(buf.Bytes()))
+	copy(bc, buf.Bytes())
+
+	err = m2.DecodeXDR(&buf)
+	if err != nil {
+		failed(bc)
+		t.Fatal(err)
+	}
+
+	ok := reflect.DeepEqual(m1, m2)
+	if !ok {
+		failed(bc)
+	}
+	return ok
+}

lib/protocol/vector.go

@@ -0,0 +1,115 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+// The Vector type represents a version vector. The zero value is a usable
+// version vector. The vector has slice semantics and some operations on it
+// are "append-like" in that they may return the same vector modified, or a
+// new allocated Vector with the modified contents.
+type Vector []Counter
+
+// Counter represents a single counter in the version vector.
+type Counter struct {
+	ID    uint64
+	Value uint64
+}
+
+// Update returns a Vector with the index for the specific ID incremented by
+// one. If it is possible, the vector v is updated and returned. If it is not,
+// a copy will be created, updated and returned.
+func (v Vector) Update(ID uint64) Vector {
+	for i := range v {
+		if v[i].ID == ID {
+			// Update an existing index
+			v[i].Value++
+			return v
+		} else if v[i].ID > ID {
+			// Insert a new index
+			nv := make(Vector, len(v)+1)
+			copy(nv, v[:i])
+			nv[i].ID = ID
+			nv[i].Value = 1
+			copy(nv[i+1:], v[i:])
+			return nv
+		}
+	}
+	// Append a new new index
+	return append(v, Counter{ID, 1})
+}
+
+// Merge returns the vector containing the maximum indexes from a and b. If it
+// is possible, the vector a is updated and returned. If it is not, a copy
+// will be created, updated and returned.
+func (a Vector) Merge(b Vector) Vector {
+	var ai, bi int
+	for bi < len(b) {
+		if ai == len(a) {
+			// We've reach the end of a, all that remains are appends
+			return append(a, b[bi:]...)
+		}
+
+		if a[ai].ID > b[bi].ID {
+			// The index from b should be inserted here
+			n := make(Vector, len(a)+1)
+			copy(n, a[:ai])
+			n[ai] = b[bi]
+			copy(n[ai+1:], a[ai:])
+			a = n
+		}
+
+		if a[ai].ID == b[bi].ID {
+			if v := b[bi].Value; v > a[ai].Value {
+				a[ai].Value = v
+			}
+		}
+
+		if bi < len(b) && a[ai].ID == b[bi].ID {
+			bi++
+		}
+		ai++
+	}
+
+	return a
+}
+
+// Copy returns an identical vector that is not shared with v.
+func (v Vector) Copy() Vector {
+	nv := make(Vector, len(v))
+	copy(nv, v)
+	return nv
+}
+
+// Equal returns true when the two vectors are equivalent.
+func (a Vector) Equal(b Vector) bool {
+	return a.Compare(b) == Equal
+}
+
+// LesserEqual returns true when the two vectors are equivalent or a is Lesser
+// than b.
+func (a Vector) LesserEqual(b Vector) bool {
+	comp := a.Compare(b)
+	return comp == Lesser || comp == Equal
+}
+
+// LesserEqual returns true when the two vectors are equivalent or a is Greater
+// than b.
+func (a Vector) GreaterEqual(b Vector) bool {
+	comp := a.Compare(b)
+	return comp == Greater || comp == Equal
+}
+
+// Concurrent returns true when the two vectors are concrurrent.
+func (a Vector) Concurrent(b Vector) bool {
+	comp := a.Compare(b)
+	return comp == ConcurrentGreater || comp == ConcurrentLesser
+}
+
+// Counter returns the current value of the given counter ID.
+func (v Vector) Counter(id uint64) uint64 {
+	for _, c := range v {
+		if c.ID == id {
+			return c.Value
+		}
+	}
+	return 0
+}

lib/protocol/vector_compare.go

@@ -0,0 +1,89 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+// Ordering represents the relationship between two Vectors.
+type Ordering int
+
+const (
+	Equal Ordering = iota
+	Greater
+	Lesser
+	ConcurrentLesser
+	ConcurrentGreater
+)
+
+// There's really no such thing as "concurrent lesser" and "concurrent
+// greater" in version vectors, just "concurrent". But it's useful to be able
+// to get a strict ordering between versions for stable sorts and so on, so we
+// return both variants. The convenience method Concurrent() can be used to
+// check for either case.
+
+// Compare returns the Ordering that describes a's relation to b.
+func (a Vector) Compare(b Vector) Ordering {
+	var ai, bi int     // index into a and b
+	var av, bv Counter // value at current index
+
+	result := Equal
+
+	for ai < len(a) || bi < len(b) {
+		var aMissing, bMissing bool
+
+		if ai < len(a) {
+			av = a[ai]
+		} else {
+			av = Counter{}
+			aMissing = true
+		}
+
+		if bi < len(b) {
+			bv = b[bi]
+		} else {
+			bv = Counter{}
+			bMissing = true
+		}
+
+		switch {
+		case av.ID == bv.ID:
+			// We have a counter value for each side
+			if av.Value > bv.Value {
+				if result == Lesser {
+					return ConcurrentLesser
+				}
+				result = Greater
+			} else if av.Value < bv.Value {
+				if result == Greater {
+					return ConcurrentGreater
+				}
+				result = Lesser
+			}
+
+		case !aMissing && av.ID < bv.ID || bMissing:
+			// Value is missing on the b side
+			if av.Value > 0 {
+				if result == Lesser {
+					return ConcurrentLesser
+				}
+				result = Greater
+			}
+
+		case !bMissing && bv.ID < av.ID || aMissing:
+			// Value is missing on the a side
+			if bv.Value > 0 {
+				if result == Greater {
+					return ConcurrentGreater
+				}
+				result = Lesser
+			}
+		}
+
+		if ai < len(a) && (av.ID <= bv.ID || bMissing) {
+			ai++
+		}
+		if bi < len(b) && (bv.ID <= av.ID || aMissing) {
+			bi++
+		}
+	}
+
+	return result
+}

lib/protocol/vector_compare_test.go

@@ -0,0 +1,249 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+import (
+	"math"
+	"testing"
+)
+
+func TestCompare(t *testing.T) {
+	testcases := []struct {
+		a, b Vector
+		r    Ordering
+	}{
+		// Empty vectors are identical
+		{Vector{}, Vector{}, Equal},
+		{Vector{}, nil, Equal},
+		{nil, Vector{}, Equal},
+		{nil, Vector{Counter{42, 0}}, Equal},
+		{Vector{}, Vector{Counter{42, 0}}, Equal},
+		{Vector{Counter{42, 0}}, nil, Equal},
+		{Vector{Counter{42, 0}}, Vector{}, Equal},
+
+		// Zero is the implied value for a missing Counter
+		{
+			Vector{Counter{42, 0}},
+			Vector{Counter{77, 0}},
+			Equal,
+		},
+
+		// Equal vectors are equal
+		{
+			Vector{Counter{42, 33}},
+			Vector{Counter{42, 33}},
+			Equal,
+		},
+		{
+			Vector{Counter{42, 33}, Counter{77, 24}},
+			Vector{Counter{42, 33}, Counter{77, 24}},
+			Equal,
+		},
+
+		// These a-vectors are all greater than the b-vector
+		{
+			Vector{Counter{42, 1}},
+			nil,
+			Greater,
+		},
+		{
+			Vector{Counter{42, 1}},
+			Vector{},
+			Greater,
+		},
+		{
+			Vector{Counter{0, 1}},
+			Vector{Counter{0, 0}},
+			Greater,
+		},
+		{
+			Vector{Counter{42, 1}},
+			Vector{Counter{42, 0}},
+			Greater,
+		},
+		{
+			Vector{Counter{math.MaxUint64, 1}},
+			Vector{Counter{math.MaxUint64, 0}},
+			Greater,
+		},
+		{
+			Vector{Counter{0, math.MaxUint64}},
+			Vector{Counter{0, 0}},
+			Greater,
+		},
+		{
+			Vector{Counter{42, math.MaxUint64}},
+			Vector{Counter{42, 0}},
+			Greater,
+		},
+		{
+			Vector{Counter{math.MaxUint64, math.MaxUint64}},
+			Vector{Counter{math.MaxUint64, 0}},
+			Greater,
+		},
+		{
+			Vector{Counter{0, math.MaxUint64}},
+			Vector{Counter{0, math.MaxUint64 - 1}},
+			Greater,
+		},
+		{
+			Vector{Counter{42, math.MaxUint64}},
+			Vector{Counter{42, math.MaxUint64 - 1}},
+			Greater,
+		},
+		{
+			Vector{Counter{math.MaxUint64, math.MaxUint64}},
+			Vector{Counter{math.MaxUint64, math.MaxUint64 - 1}},
+			Greater,
+		},
+		{
+			Vector{Counter{42, 2}},
+			Vector{Counter{42, 1}},
+			Greater,
+		},
+		{
+			Vector{Counter{22, 22}, Counter{42, 2}},
+			Vector{Counter{22, 22}, Counter{42, 1}},
+			Greater,
+		},
+		{
+			Vector{Counter{42, 2}, Counter{77, 3}},
+			Vector{Counter{42, 1}, Counter{77, 3}},
+			Greater,
+		},
+		{
+			Vector{Counter{22, 22}, Counter{42, 2}, Counter{77, 3}},
+			Vector{Counter{22, 22}, Counter{42, 1}, Counter{77, 3}},
+			Greater,
+		},
+		{
+			Vector{Counter{22, 23}, Counter{42, 2}, Counter{77, 4}},
+			Vector{Counter{22, 22}, Counter{42, 1}, Counter{77, 3}},
+			Greater,
+		},
+
+		// These a-vectors are all lesser than the b-vector
+		{nil, Vector{Counter{42, 1}}, Lesser},
+		{Vector{}, Vector{Counter{42, 1}}, Lesser},
+		{
+			Vector{Counter{42, 0}},
+			Vector{Counter{42, 1}},
+			Lesser,
+		},
+		{
+			Vector{Counter{42, 1}},
+			Vector{Counter{42, 2}},
+			Lesser,
+		},
+		{
+			Vector{Counter{22, 22}, Counter{42, 1}},
+			Vector{Counter{22, 22}, Counter{42, 2}},
+			Lesser,
+		},
+		{
+			Vector{Counter{42, 1}, Counter{77, 3}},
+			Vector{Counter{42, 2}, Counter{77, 3}},
+			Lesser,
+		},
+		{
+			Vector{Counter{22, 22}, Counter{42, 1}, Counter{77, 3}},
+			Vector{Counter{22, 22}, Counter{42, 2}, Counter{77, 3}},
+			Lesser,
+		},
+		{
+			Vector{Counter{22, 22}, Counter{42, 1}, Counter{77, 3}},
+			Vector{Counter{22, 23}, Counter{42, 2}, Counter{77, 4}},
+			Lesser,
+		},
+
+		// These are all in conflict
+		{
+			Vector{Counter{42, 2}},
+			Vector{Counter{43, 1}},
+			ConcurrentGreater,
+		},
+		{
+			Vector{Counter{43, 1}},
+			Vector{Counter{42, 2}},
+			ConcurrentLesser,
+		},
+		{
+			Vector{Counter{22, 23}, Counter{42, 1}},
+			Vector{Counter{22, 22}, Counter{42, 2}},
+			ConcurrentGreater,
+		},
+		{
+			Vector{Counter{22, 21}, Counter{42, 2}},
+			Vector{Counter{22, 22}, Counter{42, 1}},
+			ConcurrentLesser,
+		},
+		{
+			Vector{Counter{22, 21}, Counter{42, 2}, Counter{43, 1}},
+			Vector{Counter{20, 1}, Counter{22, 22}, Counter{42, 1}},
+			ConcurrentLesser,
+		},
+	}
+
+	for i, tc := range testcases {
+		// Test real Compare
+		if r := tc.a.Compare(tc.b); r != tc.r {
+			t.Errorf("%d: %+v.Compare(%+v) == %v (expected %v)", i, tc.a, tc.b, r, tc.r)
+		}
+
+		// Test convenience functions
+		switch tc.r {
+		case Greater:
+			if tc.a.Equal(tc.b) {
+				t.Errorf("%+v == %+v", tc.a, tc.b)
+			}
+			if tc.a.Concurrent(tc.b) {
+				t.Errorf("%+v concurrent %+v", tc.a, tc.b)
+			}
+			if !tc.a.GreaterEqual(tc.b) {
+				t.Errorf("%+v not >= %+v", tc.a, tc.b)
+			}
+			if tc.a.LesserEqual(tc.b) {
+				t.Errorf("%+v <= %+v", tc.a, tc.b)
+			}
+		case Lesser:
+			if tc.a.Concurrent(tc.b) {
+				t.Errorf("%+v concurrent %+v", tc.a, tc.b)
+			}
+			if tc.a.Equal(tc.b) {
+				t.Errorf("%+v == %+v", tc.a, tc.b)
+			}
+			if tc.a.GreaterEqual(tc.b) {
+				t.Errorf("%+v >= %+v", tc.a, tc.b)
+			}
+			if !tc.a.LesserEqual(tc.b) {
+				t.Errorf("%+v not <= %+v", tc.a, tc.b)
+			}
+		case Equal:
+			if tc.a.Concurrent(tc.b) {
+				t.Errorf("%+v concurrent %+v", tc.a, tc.b)
+			}
+			if !tc.a.Equal(tc.b) {
+				t.Errorf("%+v not == %+v", tc.a, tc.b)
+			}
+			if !tc.a.GreaterEqual(tc.b) {
+				t.Errorf("%+v not <= %+v", tc.a, tc.b)
+			}
+			if !tc.a.LesserEqual(tc.b) {
+				t.Errorf("%+v not <= %+v", tc.a, tc.b)
+			}
+		case ConcurrentLesser, ConcurrentGreater:
+			if !tc.a.Concurrent(tc.b) {
+				t.Errorf("%+v not concurrent %+v", tc.a, tc.b)
+			}
+			if tc.a.Equal(tc.b) {
+				t.Errorf("%+v == %+v", tc.a, tc.b)
+			}
+			if tc.a.GreaterEqual(tc.b) {
+				t.Errorf("%+v >= %+v", tc.a, tc.b)
+			}
+			if tc.a.LesserEqual(tc.b) {
+				t.Errorf("%+v <= %+v", tc.a, tc.b)
+			}
+		}
+	}
+}

lib/protocol/vector_test.go

@@ -0,0 +1,134 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+import "testing"
+
+func TestUpdate(t *testing.T) {
+	var v Vector
+
+	// Append
+
+	v = v.Update(42)
+	expected := Vector{Counter{42, 1}}
+
+	if v.Compare(expected) != Equal {
+		t.Errorf("Update error, %+v != %+v", v, expected)
+	}
+
+	// Insert at front
+
+	v = v.Update(36)
+	expected = Vector{Counter{36, 1}, Counter{42, 1}}
+
+	if v.Compare(expected) != Equal {
+		t.Errorf("Update error, %+v != %+v", v, expected)
+	}
+
+	// Insert in moddle
+
+	v = v.Update(37)
+	expected = Vector{Counter{36, 1}, Counter{37, 1}, Counter{42, 1}}
+
+	if v.Compare(expected) != Equal {
+		t.Errorf("Update error, %+v != %+v", v, expected)
+	}
+
+	// Update existing
+
+	v = v.Update(37)
+	expected = Vector{Counter{36, 1}, Counter{37, 2}, Counter{42, 1}}
+
+	if v.Compare(expected) != Equal {
+		t.Errorf("Update error, %+v != %+v", v, expected)
+	}
+}
+
+func TestCopy(t *testing.T) {
+	v0 := Vector{Counter{42, 1}}
+	v1 := v0.Copy()
+	v1.Update(42)
+	if v0.Compare(v1) != Lesser {
+		t.Errorf("Copy error, %+v should be ancestor of %+v", v0, v1)
+	}
+}
+
+func TestMerge(t *testing.T) {
+	testcases := []struct {
+		a, b, m Vector
+	}{
+		// No-ops
+		{
+			Vector{},
+			Vector{},
+			Vector{},
+		},
+		{
+			Vector{Counter{22, 1}, Counter{42, 1}},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+		},
+
+		// Appends
+		{
+			Vector{},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+		},
+		{
+			Vector{Counter{22, 1}},
+			Vector{Counter{42, 1}},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+		},
+		{
+			Vector{Counter{22, 1}},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+		},
+
+		// Insert
+		{
+			Vector{Counter{22, 1}, Counter{42, 1}},
+			Vector{Counter{22, 1}, Counter{23, 2}, Counter{42, 1}},
+			Vector{Counter{22, 1}, Counter{23, 2}, Counter{42, 1}},
+		},
+		{
+			Vector{Counter{42, 1}},
+			Vector{Counter{22, 1}},
+			Vector{Counter{22, 1}, Counter{42, 1}},
+		},
+
+		// Update
+		{
+			Vector{Counter{22, 1}, Counter{42, 2}},
+			Vector{Counter{22, 2}, Counter{42, 1}},
+			Vector{Counter{22, 2}, Counter{42, 2}},
+		},
+
+		// All of the above
+		{
+			Vector{Counter{10, 1}, Counter{20, 2}, Counter{30, 1}},
+			Vector{Counter{5, 1}, Counter{10, 2}, Counter{15, 1}, Counter{20, 1}, Counter{25, 1}, Counter{35, 1}},
+			Vector{Counter{5, 1}, Counter{10, 2}, Counter{15, 1}, Counter{20, 2}, Counter{25, 1}, Counter{30, 1}, Counter{35, 1}},
+		},
+	}
+
+	for i, tc := range testcases {
+		if m := tc.a.Merge(tc.b); m.Compare(tc.m) != Equal {
+			t.Errorf("%d: %+v.Merge(%+v) == %+v (expected %+v)", i, tc.a, tc.b, m, tc.m)
+		}
+	}
+}
+
+func TestCounterValue(t *testing.T) {
+	v0 := Vector{Counter{42, 1}, Counter{64, 5}}
+	if v0.Counter(42) != 1 {
+		t.Error("Counter error, %d != %d", v0.Counter(42), 1)
+	}
+	if v0.Counter(64) != 5 {
+		t.Error("Counter error, %d != %d", v0.Counter(64), 5)
+	}
+	if v0.Counter(72) != 0 {
+		t.Error("Counter error, %d != %d", v0.Counter(72), 0)
+	}
+}

lib/protocol/vector_xdr.go

@@ -0,0 +1,43 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+import "github.com/calmh/xdr"
+
+// This stuff is hacked up manually because genxdr doesn't support 'type
+// Vector []Counter' declarations and it was tricky when I tried to add it...
+
+type xdrWriter interface {
+	WriteUint32(uint32) (int, error)
+	WriteUint64(uint64) (int, error)
+}
+type xdrReader interface {
+	ReadUint32() uint32
+	ReadUint64() uint64
+}
+
+// EncodeXDRInto encodes the vector as an XDR object into the given XDR
+// encoder.
+func (v Vector) EncodeXDRInto(w xdrWriter) (int, error) {
+	w.WriteUint32(uint32(len(v)))
+	for i := range v {
+		w.WriteUint64(v[i].ID)
+		w.WriteUint64(v[i].Value)
+	}
+	return 4 + 16*len(v), nil
+}
+
+// DecodeXDRFrom decodes the XDR objects from the given reader into itself.
+func (v *Vector) DecodeXDRFrom(r xdrReader) error {
+	l := int(r.ReadUint32())
+	if l > 1e6 {
+		return xdr.ElementSizeExceeded("number of counters", l, 1e6)
+	}
+	n := make(Vector, l)
+	for i := range n {
+		n[i].ID = r.ReadUint64()
+		n[i].Value = r.ReadUint64()
+	}
+	*v = n
+	return nil
+}

lib/protocol/wireformat.go

@@ -0,0 +1,60 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"path/filepath"
+
+	"golang.org/x/text/unicode/norm"
+)
+
+type wireFormatConnection struct {
+	next Connection
+}
+
+func (c wireFormatConnection) Start() {
+	c.next.Start()
+}
+
+func (c wireFormatConnection) ID() DeviceID {
+	return c.next.ID()
+}
+
+func (c wireFormatConnection) Name() string {
+	return c.next.Name()
+}
+
+func (c wireFormatConnection) Index(folder string, fs []FileInfo, flags uint32, options []Option) error {
+	var myFs = make([]FileInfo, len(fs))
+	copy(myFs, fs)
+
+	for i := range fs {
+		myFs[i].Name = norm.NFC.String(filepath.ToSlash(myFs[i].Name))
+	}
+
+	return c.next.Index(folder, myFs, flags, options)
+}
+
+func (c wireFormatConnection) IndexUpdate(folder string, fs []FileInfo, flags uint32, options []Option) error {
+	var myFs = make([]FileInfo, len(fs))
+	copy(myFs, fs)
+
+	for i := range fs {
+		myFs[i].Name = norm.NFC.String(filepath.ToSlash(myFs[i].Name))
+	}
+
+	return c.next.IndexUpdate(folder, myFs, flags, options)
+}
+
+func (c wireFormatConnection) Request(folder, name string, offset int64, size int, hash []byte, flags uint32, options []Option) ([]byte, error) {
+	name = norm.NFC.String(filepath.ToSlash(name))
+	return c.next.Request(folder, name, offset, size, hash, flags, options)
+}
+
+func (c wireFormatConnection) ClusterConfig(config ClusterConfigMessage) {
+	c.next.ClusterConfig(config)
+}
+
+func (c wireFormatConnection) Statistics() Statistics {
+	return c.next.Statistics()
+}