cloudflared-mirror/vendor/github.com/cisco/go-tls-syntax/encode.go

412 lines
8.4 KiB
Go

package syntax
import (
"bytes"
"fmt"
"reflect"
"runtime"
"sort"
"sync"
)
func Marshal(v interface{}) ([]byte, error) {
e := &encodeState{}
err := e.marshal(v, fieldOptions{})
if err != nil {
return nil, err
}
return e.Bytes(), nil
}
// Marshaler is the interface implemented by types that
// have a defined TLS encoding.
type Marshaler interface {
MarshalTLS() ([]byte, error)
}
type encodeState struct {
bytes.Buffer
}
func (e *encodeState) marshal(v interface{}, opts fieldOptions) (err error) {
defer func() {
if r := recover(); r != nil {
if _, ok := r.(runtime.Error); ok {
panic(r)
}
if s, ok := r.(string); ok {
panic(s)
}
err = r.(error)
}
}()
e.reflectValue(reflect.ValueOf(v), opts)
return nil
}
func (e *encodeState) reflectValue(v reflect.Value, opts fieldOptions) {
valueEncoder(v)(e, v, opts)
}
type encoderFunc func(e *encodeState, v reflect.Value, opts fieldOptions)
func valueEncoder(v reflect.Value) encoderFunc {
if !v.IsValid() {
panic(fmt.Errorf("Cannot encode an invalid value"))
}
return typeEncoder(v.Type())
}
var encoderCache sync.Map // map[reflect.Type]encoderFunc
func typeEncoder(t reflect.Type) encoderFunc {
if fi, ok := encoderCache.Load(t); ok {
return fi.(encoderFunc)
}
// XXX(RLB): Wait group based support for recursive types omitted
// Compute the real encoder and replace the indirect func with it.
f := newTypeEncoder(t)
encoderCache.Store(t, f)
return f
}
var (
marshalerType = reflect.TypeOf(new(Marshaler)).Elem()
)
func newTypeEncoder(t reflect.Type) encoderFunc {
var enc encoderFunc
if t.Implements(marshalerType) {
enc = marshalerEncoder
} else {
switch t.Kind() {
case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
enc = uintEncoder
case reflect.Array:
enc = newArrayEncoder(t)
case reflect.Slice:
enc = newSliceEncoder(t)
case reflect.Struct:
enc = newStructEncoder(t)
case reflect.Map:
enc = newMapEncoder(t)
case reflect.Ptr:
enc = newPointerEncoder(t)
default:
panic(fmt.Errorf("Unsupported type (%s)", t))
}
}
if t.Implements(validatorType) {
enc = newValidatorEncoder(enc)
}
return enc
}
///// Specific encoders below
func omitEncoder(e *encodeState, v reflect.Value, opts fieldOptions) {
// This space intentionally left blank
}
//////////
func marshalerEncoder(e *encodeState, v reflect.Value, opts fieldOptions) {
if v.Kind() == reflect.Ptr && v.IsNil() && !opts.optional {
panic(fmt.Errorf("Cannot encode nil pointer"))
}
if v.Kind() == reflect.Ptr && opts.optional {
if v.IsNil() {
writeUint(e, uint64(optionalFlagAbsent), 1)
return
}
writeUint(e, uint64(optionalFlagPresent), 1)
}
m, ok := v.Interface().(Marshaler)
if !ok {
panic(fmt.Errorf("Non-Marshaler passed to marshalerEncoder"))
}
b, err := m.MarshalTLS()
if err == nil {
_, err = e.Write(b)
}
if err != nil {
panic(err)
}
}
//////////
func newValidatorEncoder(raw encoderFunc) encoderFunc {
return func(e *encodeState, v reflect.Value, opts fieldOptions) {
if v.Kind() == reflect.Ptr && v.IsNil() {
// Cannot validate nil values; just pass through to encoder
raw(e, v, opts)
return
}
val, ok := v.Interface().(Validator)
if !ok {
panic(fmt.Errorf("Non-Validator passed to validatorEncoder"))
}
if err := val.ValidForTLS(); err != nil {
panic(fmt.Errorf("Invalid TLS value: %v", err))
}
raw(e, v, opts)
}
}
//////////
func uintEncoder(e *encodeState, v reflect.Value, opts fieldOptions) {
if opts.varint {
varintEncoder(e, v, opts)
return
}
writeUint(e, v.Uint(), int(v.Type().Size()))
}
func varintEncoder(e *encodeState, v reflect.Value, opts fieldOptions) {
writeVarint(e, v.Uint())
}
func writeVarint(e *encodeState, u uint64) {
if (u >> 62) > 0 {
panic(fmt.Errorf("uint value is too big for varint"))
}
var varintLen int
for _, len := range []uint{1, 2, 4, 8} {
if u < (uint64(1) << (8*len - 2)) {
varintLen = int(len)
break
}
}
twoBits := map[int]uint64{1: 0x00, 2: 0x01, 4: 0x02, 8: 0x03}[varintLen]
shift := uint(8*varintLen - 2)
writeUint(e, u|(twoBits<<shift), varintLen)
}
func writeUint(e *encodeState, u uint64, len int) {
for i := 0; i < len; i += 1 {
e.WriteByte(byte(u >> uint(8*(len-i-1))))
}
}
//////////
type arrayEncoder struct {
elemEnc encoderFunc
}
func (ae *arrayEncoder) encode(e *encodeState, v reflect.Value, opts fieldOptions) {
n := v.Len()
for i := 0; i < n; i += 1 {
ae.elemEnc(e, v.Index(i), opts)
}
}
func newArrayEncoder(t reflect.Type) encoderFunc {
enc := &arrayEncoder{typeEncoder(t.Elem())}
return enc.encode
}
//////////
func encodeLength(e *encodeState, n int, opts fieldOptions) {
if opts.maxSize > 0 && n > opts.maxSize {
panic(fmt.Errorf("Encoded length more than max [%d > %d]", n, opts.maxSize))
}
if n < opts.minSize {
panic(fmt.Errorf("Encoded length less than min [%d < %d]", n, opts.minSize))
}
switch {
case opts.omitHeader:
// None.
case opts.varintHeader:
writeVarint(e, uint64(n))
case opts.headerSize > 0:
if n>>uint(8*opts.headerSize) > 0 {
panic(fmt.Errorf("Encoded length too long for header length [%d, %d]", n, opts.headerSize))
}
writeUint(e, uint64(n), int(opts.headerSize))
default:
panic(fmt.Errorf("Cannot encode a slice without a header length"))
}
}
//////////
type sliceEncoder struct {
ae *arrayEncoder
}
func (se *sliceEncoder) encode(e *encodeState, v reflect.Value, opts fieldOptions) {
arrayState := &encodeState{}
se.ae.encode(arrayState, v, opts)
encodeLength(e, arrayState.Len(), opts)
e.Write(arrayState.Bytes())
}
func newSliceEncoder(t reflect.Type) encoderFunc {
enc := &sliceEncoder{&arrayEncoder{typeEncoder(t.Elem())}}
return enc.encode
}
//////////
type structEncoder struct {
fieldOpts []fieldOptions
fieldEncs []encoderFunc
}
func (se *structEncoder) encode(e *encodeState, v reflect.Value, opts fieldOptions) {
for i := range se.fieldEncs {
se.fieldEncs[i](e, v.Field(i), se.fieldOpts[i])
}
}
func newStructEncoder(t reflect.Type) encoderFunc {
n := t.NumField()
se := structEncoder{
fieldOpts: make([]fieldOptions, n),
fieldEncs: make([]encoderFunc, n),
}
for i := 0; i < n; i += 1 {
f := t.Field(i)
tag := f.Tag.Get("tls")
opts := parseTag(tag)
if !opts.ValidForType(f.Type) {
panic(fmt.Errorf("Tags invalid for field type"))
}
se.fieldOpts[i] = opts
if opts.omit {
se.fieldEncs[i] = omitEncoder
} else {
se.fieldEncs[i] = typeEncoder(f.Type)
}
}
return se.encode
}
//////////
type mapEncoder struct {
keyEnc encoderFunc
valEnc encoderFunc
}
type encMap struct {
keyEncs [][]byte
valEncs [][]byte
}
func (em encMap) Len() int { return len(em.keyEncs) }
func (em *encMap) Swap(i, j int) {
em.keyEncs[i], em.keyEncs[j] = em.keyEncs[j], em.keyEncs[i]
em.valEncs[i], em.valEncs[j] = em.valEncs[j], em.valEncs[i]
}
func (em encMap) Less(i, j int) bool {
return bytes.Compare(em.keyEncs[i], em.keyEncs[j]) < 0
}
func (em encMap) Size() int {
size := 0
for i := range em.keyEncs {
size += len(em.keyEncs[i]) + len(em.valEncs[i])
}
return size
}
func (em encMap) Encode(e *encodeState) {
for i := range em.keyEncs {
e.Write(em.keyEncs[i])
e.Write(em.valEncs[i])
}
}
func (me *mapEncoder) encode(e *encodeState, v reflect.Value, opts fieldOptions) {
enc := &encMap{
keyEncs: make([][]byte, v.Len()),
valEncs: make([][]byte, v.Len()),
}
nullOpts := fieldOptions{}
it := v.MapRange()
for i := 0; i < enc.Len() && it.Next(); i++ {
keyState := &encodeState{}
me.keyEnc(keyState, it.Key(), nullOpts)
enc.keyEncs[i] = keyState.Bytes()
valState := &encodeState{}
me.valEnc(valState, it.Value(), nullOpts)
enc.valEncs[i] = valState.Bytes()
}
sort.Sort(enc)
encodeLength(e, enc.Size(), opts)
enc.Encode(e)
}
func newMapEncoder(t reflect.Type) encoderFunc {
me := mapEncoder{
keyEnc: typeEncoder(t.Key()),
valEnc: typeEncoder(t.Elem()),
}
return me.encode
}
//////////
type pointerEncoder struct {
base encoderFunc
}
func (pe pointerEncoder) encode(e *encodeState, v reflect.Value, opts fieldOptions) {
if v.IsNil() && !opts.optional {
panic(fmt.Errorf("Cannot encode nil pointer"))
}
if opts.optional {
if v.IsNil() {
writeUint(e, uint64(optionalFlagAbsent), 1)
return
}
writeUint(e, uint64(optionalFlagPresent), 1)
}
pe.base(e, v.Elem(), opts)
}
func newPointerEncoder(t reflect.Type) encoderFunc {
baseEncoder := typeEncoder(t.Elem())
pe := pointerEncoder{base: baseEncoder}
return pe.encode
}