fetch.go

/*
   Copyright 2021 Erigon contributors

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package txpool

import (
	"context"
	"errors"
	"fmt"
	"sync"
	"time"

	"github.com/holiman/uint256"
	"github.com/ledgerwatch/erigon-lib/common/dbg"
	"github.com/ledgerwatch/erigon-lib/direct"
	"github.com/ledgerwatch/erigon-lib/gointerfaces/grpcutil"
	"github.com/ledgerwatch/erigon-lib/gointerfaces/remote"
	"github.com/ledgerwatch/erigon-lib/gointerfaces/sentry"
	"github.com/ledgerwatch/erigon-lib/kv"
	"github.com/ledgerwatch/erigon-lib/rlp"
	types2 "github.com/ledgerwatch/erigon-lib/types"
	"github.com/ledgerwatch/log/v3"
	"google.golang.org/grpc"
	"google.golang.org/protobuf/types/known/emptypb"
)

// Fetch connects to sentry and implements eth/66 protocol regarding the transaction
// messages. It tries to "prime" the sentry with StatusData message containing given
// genesis hash and list of forks, but with zero max block and total difficulty
// Sentry should have a logic not to overwrite statusData with messages from tx pool
type Fetch struct {
	ctx                      context.Context // Context used for cancellation and closing of the fetcher
	pool                     Pool            // Transaction pool implementation
	coreDB                   kv.RoDB
	db                       kv.RwDB
	stateChangesClient       StateChangesClient
	wg                       *sync.WaitGroup // used for synchronisation in the tests (nil when not in tests)
	stateChangesParseCtx     *types2.TxParseContext
	pooledTxsParseCtx        *types2.TxParseContext
	sentryClients            []direct.SentryClient // sentry clients that will be used for accessing the network
	stateChangesParseCtxLock sync.Mutex
	pooledTxsParseCtxLock    sync.Mutex
	logger                   log.Logger
}

type StateChangesClient interface {
	StateChanges(ctx context.Context, in *remote.StateChangeRequest, opts ...grpc.CallOption) (remote.KV_StateChangesClient, error)
}

// NewFetch creates a new fetch object that will work with given sentry clients. Since the
// SentryClient here is an interface, it is suitable for mocking in tests (mock will need
// to implement all the functions of the SentryClient interface).
func NewFetch(ctx context.Context, sentryClients []direct.SentryClient, pool Pool, stateChangesClient StateChangesClient, coreDB kv.RoDB, db kv.RwDB,
	chainID uint256.Int, logger log.Logger) *Fetch {
	f := &Fetch{
		ctx:                  ctx,
		sentryClients:        sentryClients,
		pool:                 pool,
		coreDB:               coreDB,
		db:                   db,
		stateChangesClient:   stateChangesClient,
		stateChangesParseCtx: types2.NewTxParseContext(chainID).ChainIDRequired(), //TODO: change ctx if rules changed
		pooledTxsParseCtx:    types2.NewTxParseContext(chainID).ChainIDRequired(),
		logger:               logger,
	}
	f.pooledTxsParseCtx.ValidateRLP(f.pool.ValidateSerializedTxn)
	f.stateChangesParseCtx.ValidateRLP(f.pool.ValidateSerializedTxn)

	return f
}

func (f *Fetch) SetWaitGroup(wg *sync.WaitGroup) {
	f.wg = wg
}

func (f *Fetch) threadSafeParsePooledTxn(cb func(*types2.TxParseContext) error) error {
	f.pooledTxsParseCtxLock.Lock()
	defer f.pooledTxsParseCtxLock.Unlock()
	return cb(f.pooledTxsParseCtx)
}

func (f *Fetch) threadSafeParseStateChangeTxn(cb func(*types2.TxParseContext) error) error {
	f.stateChangesParseCtxLock.Lock()
	defer f.stateChangesParseCtxLock.Unlock()
	return cb(f.stateChangesParseCtx)
}

// ConnectSentries initialises connection to the sentry
func (f *Fetch) ConnectSentries() {
	for i := range f.sentryClients {
		go func(i int) {
			f.receiveMessageLoop(f.sentryClients[i])
		}(i)
		go func(i int) {
			f.receivePeerLoop(f.sentryClients[i])
		}(i)
	}
}
func (f *Fetch) ConnectCore() {
	go func() {
		for {
			select {
			case <-f.ctx.Done():
				return
			default:
			}
			if err := f.handleStateChanges(f.ctx, f.stateChangesClient); err != nil {
				if grpcutil.IsRetryLater(err) || grpcutil.IsEndOfStream(err) {
					time.Sleep(3 * time.Second)
					continue
				}
				f.logger.Warn("[txpool.handleStateChanges]", "err", err)
			}
		}
	}()
}

func (f *Fetch) receiveMessageLoop(sentryClient sentry.SentryClient) {
	for {
		select {
		case <-f.ctx.Done():
			return
		default:
		}
		if _, err := sentryClient.HandShake(f.ctx, &emptypb.Empty{}, grpc.WaitForReady(true)); err != nil {
			if grpcutil.IsRetryLater(err) || grpcutil.IsEndOfStream(err) {
				time.Sleep(3 * time.Second)
				continue
			}
			// Report error and wait more
			f.logger.Warn("[txpool.recvMessage] sentry not ready yet", "err", err)
			continue
		}

		if err := f.receiveMessage(f.ctx, sentryClient); err != nil {
			if grpcutil.IsRetryLater(err) || grpcutil.IsEndOfStream(err) {
				time.Sleep(3 * time.Second)
				continue
			}
			f.logger.Warn("[txpool.recvMessage]", "err", err)
		}
	}
}

func (f *Fetch) receiveMessage(ctx context.Context, sentryClient sentry.SentryClient) error {
	streamCtx, cancel := context.WithCancel(ctx)
	defer cancel()
	stream, err := sentryClient.Messages(streamCtx, &sentry.MessagesRequest{Ids: []sentry.MessageId{
		sentry.MessageId_NEW_POOLED_TRANSACTION_HASHES_66,
		sentry.MessageId_GET_POOLED_TRANSACTIONS_66,
		sentry.MessageId_TRANSACTIONS_66,
		sentry.MessageId_POOLED_TRANSACTIONS_66,
		sentry.MessageId_NEW_POOLED_TRANSACTION_HASHES_68,
	}}, grpc.WaitForReady(true))
	if err != nil {
		select {
		case <-f.ctx.Done():
			return ctx.Err()
		default:
		}
		return err
	}

	var req *sentry.InboundMessage
	for req, err = stream.Recv(); ; req, err = stream.Recv() {
		if err != nil {
			select {
			case <-f.ctx.Done():
				return ctx.Err()
			default:
			}
			return err
		}
		if req == nil {
			return nil
		}
		if err := f.handleInboundMessage(streamCtx, req, sentryClient); err != nil {
			if grpcutil.IsRetryLater(err) || grpcutil.IsEndOfStream(err) {
				time.Sleep(3 * time.Second)
				continue
			}
			f.logger.Debug("[txpool.fetch] Handling incoming message", "msg", req.Id.String(), "err", err)
		}
		if f.wg != nil {
			f.wg.Done()
		}
	}
}

func (f *Fetch) handleInboundMessage(ctx context.Context, req *sentry.InboundMessage, sentryClient sentry.SentryClient) (err error) {
	defer func() {
		if rec := recover(); rec != nil {
			err = fmt.Errorf("%+v, trace: %s, rlp: %x", rec, dbg.Stack(), req.Data)
		}
	}()

	if !f.pool.Started() {
		return nil
	}
	tx, err := f.db.BeginRo(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback()

	switch req.Id {
	case sentry.MessageId_NEW_POOLED_TRANSACTION_HASHES_66:
		hashCount, pos, err := types2.ParseHashesCount(req.Data, 0)
		if err != nil {
			return fmt.Errorf("parsing NewPooledTransactionHashes: %w", err)
		}
		hashes := make([]byte, 32*hashCount)
		for i := 0; i < len(hashes); i += 32 {
			if _, pos, err = types2.ParseHash(req.Data, pos, hashes[i:]); err != nil {
				return err
			}
		}
		unknownHashes, err := f.pool.FilterKnownIdHashes(tx, hashes)
		if err != nil {
			return err
		}
		if len(unknownHashes) > 0 {
			var encodedRequest []byte
			var messageID sentry.MessageId
			if encodedRequest, err = types2.EncodeGetPooledTransactions66(unknownHashes, uint64(1), nil); err != nil {
				return err
			}
			messageID = sentry.MessageId_GET_POOLED_TRANSACTIONS_66
			if _, err = sentryClient.SendMessageById(f.ctx, &sentry.SendMessageByIdRequest{
				Data:   &sentry.OutboundMessageData{Id: messageID, Data: encodedRequest},
				PeerId: req.PeerId,
			}, &grpc.EmptyCallOption{}); err != nil {
				return err
			}
		}
	case sentry.MessageId_NEW_POOLED_TRANSACTION_HASHES_68:
		_, _, hashes, _, err := rlp.ParseAnnouncements(req.Data, 0)
		if err != nil {
			return fmt.Errorf("parsing NewPooledTransactionHashes88: %w", err)
		}
		unknownHashes, err := f.pool.FilterKnownIdHashes(tx, hashes)
		if err != nil {
			return err
		}

		if len(unknownHashes) > 0 {
			var encodedRequest []byte
			var messageID sentry.MessageId
			if encodedRequest, err = types2.EncodeGetPooledTransactions66(unknownHashes, uint64(1), nil); err != nil {
				return err
			}
			messageID = sentry.MessageId_GET_POOLED_TRANSACTIONS_66
			if _, err = sentryClient.SendMessageById(f.ctx, &sentry.SendMessageByIdRequest{
				Data:   &sentry.OutboundMessageData{Id: messageID, Data: encodedRequest},
				PeerId: req.PeerId,
			}, &grpc.EmptyCallOption{}); err != nil {
				return err
			}
		}
	case sentry.MessageId_GET_POOLED_TRANSACTIONS_66:
		//TODO: handleInboundMessage is single-threaded - means it can accept as argument couple buffers (or analog of txParseContext). Protobuf encoding will copy data anyway, but DirectClient doesn't
		var encodedRequest []byte
		var messageID sentry.MessageId
		messageID = sentry.MessageId_POOLED_TRANSACTIONS_66
		requestID, hashes, _, err := types2.ParseGetPooledTransactions66(req.Data, 0, nil)
		if err != nil {
			return err
		}
		_ = requestID
		var txs [][]byte
		for i := 0; i < len(hashes); i += 32 {
			txn, err := f.pool.GetRlp(tx, hashes[i:i+32])
			if err != nil {
				return err
			}
			if txn == nil {
				continue
			}
			txs = append(txs, txn)
		}
		encodedRequest = types2.EncodePooledTransactions66(txs, requestID, nil)

		if _, err := sentryClient.SendMessageById(f.ctx, &sentry.SendMessageByIdRequest{
			Data:   &sentry.OutboundMessageData{Id: messageID, Data: encodedRequest},
			PeerId: req.PeerId,
		}, &grpc.EmptyCallOption{}); err != nil {
			return err
		}
	case sentry.MessageId_POOLED_TRANSACTIONS_66, sentry.MessageId_TRANSACTIONS_66:
		txs := types2.TxSlots{}
		if err := f.threadSafeParsePooledTxn(func(parseContext *types2.TxParseContext) error {
			return nil
		}); err != nil {
			return err
		}

		switch req.Id {
		case sentry.MessageId_TRANSACTIONS_66:
			if err := f.threadSafeParsePooledTxn(func(parseContext *types2.TxParseContext) error {
				if _, err := types2.ParseTransactions(req.Data, 0, parseContext, &txs, func(hash []byte) error {
					known, err := f.pool.IdHashKnown(tx, hash)
					if err != nil {
						return err
					}
					if known {
						return types2.ErrRejected
					}
					return nil
				}); err != nil {
					return err
				}
				return nil
			}); err != nil {
				return err
			}
		case sentry.MessageId_POOLED_TRANSACTIONS_66:
			if err := f.threadSafeParsePooledTxn(func(parseContext *types2.TxParseContext) error {
				if _, _, err := types2.ParsePooledTransactions66(req.Data, 0, parseContext, &txs, func(hash []byte) error {
					known, err := f.pool.IdHashKnown(tx, hash)
					if err != nil {
						return err
					}
					if known {
						return types2.ErrRejected
					}
					return nil
				}); err != nil {
					return err
				}
				return nil
			}); err != nil {
				return err
			}
		default:
			return fmt.Errorf("unexpected message: %s", req.Id.String())
		}
		if len(txs.Txs) == 0 {
			return nil
		}
		f.pool.AddRemoteTxs(ctx, txs)
	default:
		defer f.logger.Trace("[txpool] dropped p2p message", "id", req.Id)
	}

	return nil
}

func (f *Fetch) receivePeerLoop(sentryClient sentry.SentryClient) {
	for {
		select {
		case <-f.ctx.Done():
			return
		default:
		}
		if _, err := sentryClient.HandShake(f.ctx, &emptypb.Empty{}, grpc.WaitForReady(true)); err != nil {
			if grpcutil.IsRetryLater(err) || grpcutil.IsEndOfStream(err) {
				time.Sleep(3 * time.Second)
				continue
			}
			// Report error and wait more
			f.logger.Warn("[txpool.recvPeers] sentry not ready yet", "err", err)
			time.Sleep(time.Second)
			continue
		}
		if err := f.receivePeer(sentryClient); err != nil {
			if grpcutil.IsRetryLater(err) || grpcutil.IsEndOfStream(err) {
				time.Sleep(3 * time.Second)
				continue
			}

			f.logger.Warn("[txpool.recvPeers]", "err", err)
		}
	}
}

func (f *Fetch) receivePeer(sentryClient sentry.SentryClient) error {
	streamCtx, cancel := context.WithCancel(f.ctx)
	defer cancel()

	stream, err := sentryClient.PeerEvents(streamCtx, &sentry.PeerEventsRequest{})
	if err != nil {
		select {
		case <-f.ctx.Done():
			return f.ctx.Err()
		default:
		}
		return err
	}

	var req *sentry.PeerEvent
	for req, err = stream.Recv(); ; req, err = stream.Recv() {
		if err != nil {
			return err
		}
		if req == nil {
			return nil
		}
		if err = f.handleNewPeer(req); err != nil {
			return err
		}
		if f.wg != nil {
			f.wg.Done()
		}
	}
}

func (f *Fetch) handleNewPeer(req *sentry.PeerEvent) error {
	if req == nil {
		return nil
	}
	switch req.EventId {
	case sentry.PeerEvent_Connect:
		f.pool.AddNewGoodPeer(req.PeerId)
	}

	return nil
}

func (f *Fetch) handleStateChanges(ctx context.Context, client StateChangesClient) error {
	streamCtx, cancel := context.WithCancel(ctx)
	defer cancel()
	stream, err := client.StateChanges(streamCtx, &remote.StateChangeRequest{WithStorage: false, WithTransactions: true}, grpc.WaitForReady(true))
	if err != nil {
		return err
	}
	tx, err := f.db.BeginRo(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback()
	for req, err := stream.Recv(); ; req, err = stream.Recv() {
		if err != nil {
			return err
		}
		if req == nil {
			return nil
		}

		var unwindTxs, minedTxs types2.TxSlots
		for _, change := range req.ChangeBatch {
			if change.Direction == remote.Direction_FORWARD {
				minedTxs.Resize(uint(len(change.Txs)))
				for i := range change.Txs {
					minedTxs.Txs[i] = &types2.TxSlot{}
					if err = f.threadSafeParseStateChangeTxn(func(parseContext *types2.TxParseContext) error {
						_, err := parseContext.ParseTransaction(change.Txs[i], 0, minedTxs.Txs[i], minedTxs.Senders.At(i), false /* hasEnvelope */, false /* wrappedWithBlobs */, nil)
						return err
					}); err != nil && !errors.Is(err, context.Canceled) {
						f.logger.Warn("stream.Recv", "err", err)
						continue
					}
				}
			}
			if change.Direction == remote.Direction_UNWIND {
				for i := range change.Txs {
					if err = f.threadSafeParseStateChangeTxn(func(parseContext *types2.TxParseContext) error {
						utx := &types2.TxSlot{}
						sender := make([]byte, 20)
						_, err2 := parseContext.ParseTransaction(change.Txs[i], 0, utx, sender, false /* hasEnvelope */, false /* wrappedWithBlobs */, nil)
						if err2 != nil {
							return err2
						}
						if utx.Type == types2.BlobTxType {
							knownBlobTxn, err2 := f.pool.GetKnownBlobTxn(tx, utx.IDHash[:])
							if err2 != nil {
								return err2
							}
							// Get the blob tx from cache; ignore altogether if it isn't there
							if knownBlobTxn != nil {
								unwindTxs.Append(knownBlobTxn.Tx, sender, false)
							}
						} else {
							unwindTxs.Append(utx, sender, false)
						}
						return err
					}); err != nil && !errors.Is(err, context.Canceled) {
						f.logger.Warn("stream.Recv", "err", err)
						continue
					}
				}
			}
		}

		if err := f.db.View(ctx, func(tx kv.Tx) error {
			return f.pool.OnNewBlock(ctx, req, unwindTxs, minedTxs, tx)
		}); err != nil && !errors.Is(err, context.Canceled) {
			f.logger.Warn("onNewBlock", "err", err)
		}
		if f.wg != nil {
			f.wg.Done()
		}
	}
}