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rldp.go
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rldp.go
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package rldp
import (
"context"
"crypto/ed25519"
"crypto/rand"
"encoding/hex"
"fmt"
"github.com/xssnick/tonutils-go/adnl"
"github.com/xssnick/tonutils-go/adnl/rldp/raptorq"
"github.com/xssnick/tonutils-go/tl"
"log"
"reflect"
"sync"
"time"
)
func init() {
tl.Register(Query{}, "rldp.query query_id:int256 max_answer_size:long timeout:int data:bytes = rldp.Message")
tl.Register(Answer{}, "rldp.answer query_id:int256 data:bytes = rldp.Message")
tl.Register(Message{}, "rldp.message id:int256 data:bytes = rldp.Message")
tl.Register(Confirm{}, "rldp.confirm transfer_id:int256 part:int seqno:int = rldp.MessagePart")
tl.Register(Complete{}, "rldp.complete transfer_id:int256 part:int = rldp.MessagePart")
tl.Register(MessagePart{}, "rldp.messagePart transfer_id:int256 fec_type:fec.Type part:int total_size:long seqno:int data:bytes = rldp.MessagePart")
}
const _SymbolSize = 768
const _PacketWaitTime = 15 * time.Millisecond
type Query struct {
ID []byte `tl:"int256"`
MaxAnswerSize int64 `tl:"long"`
Timeout int32 `tl:"int"`
Data any `tl:"bytes struct boxed"`
}
type Answer struct {
ID []byte `tl:"int256"`
Data any `tl:"bytes struct boxed"`
}
type Message struct {
ID []byte `tl:"int256"`
Data []byte `tl:"bytes"`
}
type Confirm struct {
TransferID []byte `tl:"int256"`
Part int32 `tl:"int"`
Seqno int32 `tl:"int"`
}
type Complete struct {
TransferID []byte `tl:"int256"`
Part int32 `tl:"int"`
}
type MessagePart struct {
TransferID []byte `tl:"int256"`
FecType any `tl:"struct boxed [fec.roundRobin,fec.raptorQ,fec.online]"`
Part int32 `tl:"int"`
TotalSize int64 `tl:"long"`
Seqno int32 `tl:"int"`
Data []byte `tl:"bytes"`
}
type RLDP struct {
adnl *adnl.ADNL
activeRequests map[string]chan any
activeTransfers map[string]chan bool
recvStreams map[string]*decoderStream // TODO: cleanup old
onQuery func(query *Query) error
onDisconnect func()
mx sync.Mutex
}
type decoderStream struct {
decoder *raptorq.Decoder
finishedAt *time.Time
lastCompleteAt *time.Time
mx sync.Mutex
}
func NewRLDP(a *adnl.ADNL) *RLDP {
r := &RLDP{
adnl: a,
activeRequests: map[string]chan any{},
activeTransfers: map[string]chan bool{},
recvStreams: map[string]*decoderStream{},
}
a.SetCustomMessageHandler(r.handleMessage)
a.SetDisconnectHandler(r.handleADNLDisconnect)
return r
}
func (r *RLDP) SetOnQuery(handler func(query *Query) error) {
r.onQuery = handler
}
func (r *RLDP) SetOnDisconnect(handler func()) {
r.onDisconnect = handler
}
func (r *RLDP) Close() {
r.adnl.Close()
}
func (r *RLDP) handleADNLDisconnect(addr string, key ed25519.PublicKey) {
r.adnl.Close()
disc := r.onDisconnect
if disc != nil {
disc()
}
}
func (r *RLDP) handleMessage(msg *adnl.MessageCustom) error {
switch m := msg.Data.(type) {
case MessagePart:
fec, ok := m.FecType.(FECRaptorQ)
if !ok {
return fmt.Errorf("not supported fec type")
}
id := hex.EncodeToString(m.TransferID)
r.mx.Lock()
stream := r.recvStreams[id]
r.mx.Unlock()
if stream == nil {
dec, err := raptorq.NewRaptorQ(uint32(fec.SymbolSize)).CreateDecoder(uint32(fec.DataSize))
if err != nil {
return fmt.Errorf("failed to init raptorq decoder: %w", err)
}
stream = &decoderStream{
decoder: dec,
}
r.mx.Lock()
r.recvStreams[id] = stream
r.mx.Unlock()
} else if stream.finishedAt != nil {
if stream.lastCompleteAt == nil ||
stream.lastCompleteAt.Add(_PacketWaitTime).Before(time.Now()) { // we not send completions too often, to not get socket buffer overflow
// got packet for a finished stream, let them know that it is completed, again
err := r.adnl.SendCustomMessage(context.Background(), Complete{
TransferID: m.TransferID,
Part: m.Part,
})
if err != nil {
return fmt.Errorf("failed to send rldp complete message: %w", err)
}
tm := time.Now()
r.mx.Lock()
r.recvStreams[id].lastCompleteAt = &tm
r.mx.Unlock()
}
return nil
}
canTryDecode, err := stream.decoder.AddSymbol(uint32(m.Seqno), m.Data)
if err != nil {
return fmt.Errorf("failed to add raptorq symbol %d: %w", m.Seqno, err)
}
if canTryDecode {
decoded, data, err := stream.decoder.Decode()
if err != nil {
return fmt.Errorf("failed to decode raptorq packet: %w", err)
}
// it may not be decoded due to unsolvable math system, it means we need more symbols
if decoded {
tm := time.Now()
r.mx.Lock()
r.recvStreams[id] = &decoderStream{finishedAt: &tm}
r.mx.Unlock()
var res any
_, err = tl.Parse(&res, data, true)
if err != nil {
return fmt.Errorf("failed to parse custom message: %w", err)
}
// TODO: add multiple parts support (check if applicable)
err = r.adnl.SendCustomMessage(context.Background(), Complete{
TransferID: m.TransferID,
Part: m.Part,
})
if err != nil {
return fmt.Errorf("failed to send rldp complete message: %w", err)
}
switch rVal := res.(type) {
case Query:
handler := r.onQuery
if handler != nil {
go func() {
if err = handler(&rVal); err != nil {
log.Println("failed to handle query: ", err)
}
}()
}
case Answer:
qid := hex.EncodeToString(rVal.ID)
r.mx.Lock()
req := r.activeRequests[qid]
if req != nil {
delete(r.activeRequests, qid)
}
r.mx.Unlock()
if req != nil {
req <- rVal.Data
}
default:
log.Println("skipping unwanted rldp message of type", reflect.TypeOf(res).String())
}
}
}
case Complete: // receiver has fully received transfer, close our stream
id := hex.EncodeToString(m.TransferID)
r.mx.Lock()
t := r.activeTransfers[id]
if t != nil {
delete(r.activeTransfers, id)
}
r.mx.Unlock()
if t != nil {
t <- true
}
default:
return fmt.Errorf("unexpected message type %s", reflect.TypeOf(m).String())
}
return nil
}
func (r *RLDP) sendMessageParts(ctx context.Context, data []byte) error {
enc, err := raptorq.NewRaptorQ(_SymbolSize).CreateEncoder(data)
if err != nil {
return fmt.Errorf("failed to create raptorq object encoder: %w", err)
}
tid := make([]byte, 32)
_, err = rand.Read(tid)
if err != nil {
return err
}
id := hex.EncodeToString(tid)
ch := make(chan bool, 1)
r.mx.Lock()
r.activeTransfers[id] = ch
r.mx.Unlock()
defer func() {
r.mx.Lock()
delete(r.activeTransfers, id)
r.mx.Unlock()
}()
symbolsSent := uint32(0)
for {
select {
case <-ctx.Done():
// too slow receiver, finish sending
return ctx.Err()
case <-ch:
// we got complete from receiver, finish sending
return nil
default:
}
if symbolsSent > enc.BaseSymbolsNum()+enc.BaseSymbolsNum()/2 { //+enc.BaseSymbolsNum()/2
x := symbolsSent - (enc.BaseSymbolsNum() + enc.BaseSymbolsNum()/2)
select {
case <-ctx.Done():
// too slow receiver, finish sending
return ctx.Err()
case <-ch:
// we got complete from receiver, finish sending
return nil
case <-time.After(time.Duration(x) * _PacketWaitTime):
// send additional FEC recovery parts until complete
}
}
p := MessagePart{
TransferID: tid,
FecType: FECRaptorQ{
DataSize: int32(len(data)),
SymbolSize: _SymbolSize,
SymbolsCount: int32(enc.BaseSymbolsNum()),
},
Part: int32(0),
TotalSize: int64(len(data)),
Seqno: int32(symbolsSent),
Data: enc.GenSymbol(symbolsSent),
}
err = r.adnl.SendCustomMessage(ctx, p)
if err != nil {
return fmt.Errorf("failed to send message part %d: %w", symbolsSent, err)
}
symbolsSent++
}
}
func (r *RLDP) DoQuery(ctx context.Context, maxAnswerSize int64, query, result tl.Serializable) error {
timeout, ok := ctx.Deadline()
if !ok {
timeout = time.Now().Add(15 * time.Second)
}
qid := make([]byte, 32)
_, err := rand.Read(qid)
if err != nil {
return err
}
q := &Query{
ID: qid,
MaxAnswerSize: maxAnswerSize,
Timeout: int32(timeout.Unix()),
Data: query,
}
queryID := hex.EncodeToString(q.ID)
res := make(chan any, 2)
r.mx.Lock()
r.activeRequests[queryID] = res
r.mx.Unlock()
defer func() {
// we need it to delete in case of err
r.mx.Lock()
delete(r.activeRequests, queryID)
r.mx.Unlock()
}()
data, err := tl.Serialize(q, true)
if err != nil {
return fmt.Errorf("failed to serialize query: %w", err)
}
sndCtx, cancel := context.WithDeadline(ctx, timeout)
defer cancel()
go func() {
err = r.sendMessageParts(sndCtx, data)
if err != nil {
res <- fmt.Errorf("failed to send query parts: %w", err)
}
}()
select {
case resp := <-res:
if err, ok = resp.(error); ok {
return err
}
reflect.ValueOf(result).Elem().Set(reflect.ValueOf(resp))
return nil
case <-ctx.Done():
return fmt.Errorf("response deadline exceeded, err: %w", ctx.Err())
}
}
func (r *RLDP) SendAnswer(ctx context.Context, maxAnswerSize int64, queryID []byte, answer tl.Serializable) error {
a := Answer{
ID: queryID,
Data: answer,
}
data, err := tl.Serialize(a, true)
if err != nil {
return fmt.Errorf("failed to serialize query: %w", err)
}
if int64(len(data)) > maxAnswerSize {
return fmt.Errorf("too big answer for that client, client wants no more than %d bytes", maxAnswerSize)
}
if err = r.sendMessageParts(ctx, data); err != nil {
return fmt.Errorf("failed to send partitioned answer: %w", err)
}
return nil
}