package mempool import ( "errors" "fmt" "math" "sync" "time" cfg "github.com/tendermint/tendermint/config" "github.com/tendermint/tendermint/libs/clist" "github.com/tendermint/tendermint/libs/log" "github.com/tendermint/tendermint/libs/service" tmsync "github.com/tendermint/tendermint/libs/sync" "github.com/tendermint/tendermint/p2p" protomem "github.com/tendermint/tendermint/proto/tendermint/mempool" "github.com/tendermint/tendermint/types" ) var ( _ service.Service = (*Reactor)(nil) _ p2p.Wrapper = (*protomem.Message)(nil) ) const ( MempoolChannel = p2p.ChannelID(0x30) // peerCatchupSleepIntervalMS defines how much time to sleep if a peer is behind peerCatchupSleepIntervalMS = 100 // UnknownPeerID is the peer ID to use when running CheckTx when there is // no peer (e.g. RPC) UnknownPeerID uint16 = 0 maxActiveIDs = math.MaxUint16 ) // PeerManager defines the interface contract required for getting necessary // peer information. This should eventually be replaced with a message-oriented // approach utilizing the p2p stack. type PeerManager interface { GetHeight(p2p.NodeID) int64 } // Reactor implements a service that contains mempool of txs that are broadcasted // amongst peers. It maintains a map from peer ID to counter, to prevent gossiping // txs to the peers you received it from. type Reactor struct { service.BaseService config *cfg.MempoolConfig mempool *CListMempool ids *mempoolIDs // XXX: Currently, this is the only way to get information about a peer. Ideally, // we rely on message-oriented communication to get necessary peer data. // ref: https://github.com/tendermint/tendermint/issues/5670 peerMgr PeerManager mempoolCh *p2p.Channel peerUpdates *p2p.PeerUpdatesCh closeCh chan struct{} // peerWG is used to coordinate graceful termination of all peer broadcasting // goroutines. peerWG sync.WaitGroup mtx tmsync.Mutex peerRoutines map[p2p.NodeID]*tmsync.Closer } // NewReactor returns a reference to a new reactor. func NewReactor( logger log.Logger, config *cfg.MempoolConfig, peerMgr PeerManager, mempool *CListMempool, mempoolCh *p2p.Channel, peerUpdates *p2p.PeerUpdatesCh, ) *Reactor { r := &Reactor{ config: config, peerMgr: peerMgr, mempool: mempool, ids: newMempoolIDs(), mempoolCh: mempoolCh, peerUpdates: peerUpdates, closeCh: make(chan struct{}), peerRoutines: make(map[p2p.NodeID]*tmsync.Closer), } r.BaseService = *service.NewBaseService(logger, "Mempool", r) return r } // GetChannelShims returns a map of ChannelDescriptorShim objects, where each // object wraps a reference to a legacy p2p ChannelDescriptor and the corresponding // p2p proto.Message the new p2p Channel is responsible for handling. // // // TODO: Remove once p2p refactor is complete. // ref: https://github.com/tendermint/tendermint/issues/5670 func GetChannelShims(config *cfg.MempoolConfig) map[p2p.ChannelID]*p2p.ChannelDescriptorShim { largestTx := make([]byte, config.MaxTxBytes) batchMsg := protomem.Message{ Sum: &protomem.Message_Txs{ Txs: &protomem.Txs{Txs: [][]byte{largestTx}}, }, } return map[p2p.ChannelID]*p2p.ChannelDescriptorShim{ MempoolChannel: { MsgType: new(protomem.Message), Descriptor: &p2p.ChannelDescriptor{ ID: byte(MempoolChannel), Priority: 5, RecvMessageCapacity: batchMsg.Size(), }, }, } } // OnStart starts separate go routines for each p2p Channel and listens for // envelopes on each. In addition, it also listens for peer updates and handles // messages on that p2p channel accordingly. The caller must be sure to execute // OnStop to ensure the outbound p2p Channels are closed. func (r *Reactor) OnStart() error { if !r.config.Broadcast { r.Logger.Info("tx broadcasting is disabled") } go r.processMempoolCh() go r.processPeerUpdates() return nil } // OnStop stops the reactor by signaling to all spawned goroutines to exit and // blocking until they all exit. func (r *Reactor) OnStop() { r.mtx.Lock() for _, c := range r.peerRoutines { c.Close() } r.mtx.Unlock() // wait for all spawned peer tx broadcasting goroutines to gracefully exit r.peerWG.Wait() // Close closeCh to signal to all spawned goroutines to gracefully exit. All // p2p Channels should execute Close(). close(r.closeCh) // Wait for all p2p Channels to be closed before returning. This ensures we // can easily reason about synchronization of all p2p Channels and ensure no // panics will occur. <-r.mempoolCh.Done() <-r.peerUpdates.Done() } // handleMempoolMessage handles envelopes sent from peers on the MempoolChannel. // For every tx in the message, we execute CheckTx. It returns an error if an // empty set of txs are sent in an envelope or if we receive an unexpected // message type. func (r *Reactor) handleMempoolMessage(envelope p2p.Envelope) error { logger := r.Logger.With("peer", envelope.From) switch msg := envelope.Message.(type) { case *protomem.Txs: protoTxs := msg.GetTxs() if len(protoTxs) == 0 { return errors.New("empty txs received from peer") } txInfo := TxInfo{SenderID: r.ids.GetForPeer(envelope.From)} if len(envelope.From) != 0 { txInfo.SenderP2PID = envelope.From } for _, tx := range protoTxs { if err := r.mempool.CheckTx(types.Tx(tx), nil, txInfo); err != nil { logger.Error("checktx failed for tx", "tx", txID(tx), "err", err) } } default: return fmt.Errorf("received unknown message: %T", msg) } return nil } // handleMessage handles an Envelope sent from a peer on a specific p2p Channel. // It will handle errors and any possible panics gracefully. A caller can handle // any error returned by sending a PeerError on the respective channel. func (r *Reactor) handleMessage(chID p2p.ChannelID, envelope p2p.Envelope) (err error) { defer func() { if e := recover(); e != nil { err = fmt.Errorf("panic in processing message: %v", e) } }() r.Logger.Debug("received message", "peer", envelope.From) switch chID { case MempoolChannel: err = r.handleMempoolMessage(envelope) default: err = fmt.Errorf("unknown channel ID (%d) for envelope (%v)", chID, envelope) } return err } // processMempoolCh implements a blocking event loop where we listen for p2p // Envelope messages from the mempoolCh. func (r *Reactor) processMempoolCh() { defer r.mempoolCh.Close() for { select { case envelope := <-r.mempoolCh.In(): if err := r.handleMessage(r.mempoolCh.ID(), envelope); err != nil { r.Logger.Error("failed to process message", "ch_id", r.mempoolCh.ID(), "envelope", envelope, "err", err) r.mempoolCh.Error() <- p2p.PeerError{ PeerID: envelope.From, Err: err, Severity: p2p.PeerErrorSeverityLow, } } case <-r.closeCh: r.Logger.Debug("stopped listening on mempool channel; closing...") return } } } // processPeerUpdate processes a PeerUpdate. For added peers, PeerStatusUp, we // check if the reactor is running and if we've already started a tx broadcasting // goroutine or not. If not, we start one for the newly added peer. For down or // removed peers, we remove the peer from the mempool peer ID set and signal to // stop the tx broadcasting goroutine. func (r *Reactor) processPeerUpdate(peerUpdate p2p.PeerUpdate) { r.Logger.Debug("received peer update", "peer", peerUpdate.PeerID, "status", peerUpdate.Status) r.mtx.Lock() defer r.mtx.Unlock() switch peerUpdate.Status { case p2p.PeerStatusUp: // Do not allow starting new tx broadcast loops after reactor shutdown // has been initiated. This can happen after we've manually closed all // peer broadcast loops and closed r.closeCh, but the router still sends // in-flight peer updates. if !r.IsRunning() { return } if r.config.Broadcast { // Check if we've already started a goroutine for this peer, if not we create // a new done channel so we can explicitly close the goroutine if the peer // is later removed, we increment the waitgroup so the reactor can stop // safely, and finally start the goroutine to broadcast txs to that peer. _, ok := r.peerRoutines[peerUpdate.PeerID] if !ok { closer := tmsync.NewCloser() r.peerRoutines[peerUpdate.PeerID] = closer r.peerWG.Add(1) r.ids.ReserveForPeer(peerUpdate.PeerID) // start a broadcast routine ensuring all txs are forwarded to the peer go r.broadcastTxRoutine(peerUpdate.PeerID, closer) } } case p2p.PeerStatusDown, p2p.PeerStatusRemoved, p2p.PeerStatusBanned: r.ids.Reclaim(peerUpdate.PeerID) // Check if we've started a tx broadcasting goroutine for this peer. // If we have, we signal to terminate the goroutine via the channel's closure. // This will internally decrement the peer waitgroup and remove the peer // from the map of peer tx broadcasting goroutines. closer, ok := r.peerRoutines[peerUpdate.PeerID] if ok { closer.Close() } } } // processPeerUpdates initiates a blocking process where we listen for and handle // PeerUpdate messages. When the reactor is stopped, we will catch the signal and // close the p2p PeerUpdatesCh gracefully. func (r *Reactor) processPeerUpdates() { defer r.peerUpdates.Close() for { select { case peerUpdate := <-r.peerUpdates.Updates(): r.processPeerUpdate(peerUpdate) case <-r.closeCh: r.Logger.Debug("stopped listening on peer updates channel; closing...") return } } } func (r *Reactor) broadcastTxRoutine(peerID p2p.NodeID, closer *tmsync.Closer) { peerMempoolID := r.ids.GetForPeer(peerID) var next *clist.CElement // remove the peer ID from the map of routines and mark the waitgroup as done defer func() { r.mtx.Lock() delete(r.peerRoutines, peerID) r.mtx.Unlock() r.peerWG.Done() if e := recover(); e != nil { r.Logger.Error("recovering from broadcasting mempool loop", "err", e) } }() for { if !r.IsRunning() { return } // This happens because the CElement we were looking at got garbage // collected (removed). That is, .NextWait() returned nil. Go ahead and // start from the beginning. if next == nil { select { case <-r.mempool.TxsWaitChan(): // wait until a tx is available if next = r.mempool.TxsFront(); next == nil { continue } case <-closer.Done(): // The peer is marked for removal via a PeerUpdate as the doneCh was // explicitly closed to signal we should exit. return case <-r.closeCh: // The reactor has signaled that we are stopped and thus we should // implicitly exit this peer's goroutine. return } } memTx := next.Value.(*mempoolTx) if r.peerMgr != nil { height := r.peerMgr.GetHeight(peerID) if height > 0 && height < memTx.Height()-1 { // allow for a lag of one block time.Sleep(peerCatchupSleepIntervalMS * time.Millisecond) continue } } // NOTE: Transaction batching was disabled due to: // https://github.com/tendermint/tendermint/issues/5796 if _, ok := memTx.senders.Load(peerMempoolID); !ok { // Send the mempool tx to the corresponding peer. Note, the peer may be // behind and thus would not be able to process the mempool tx correctly. r.mempoolCh.Out() <- p2p.Envelope{ To: peerID, Message: &protomem.Txs{ Txs: [][]byte{memTx.tx}, }, } r.Logger.Debug("gossiped tx to peer", "tx", txID(memTx.tx), "peer", peerID) } select { case <-next.NextWaitChan(): // see the start of the for loop for nil check next = next.Next() case <-closer.Done(): // The peer is marked for removal via a PeerUpdate as the doneCh was // explicitly closed to signal we should exit. return case <-r.closeCh: // The reactor has signaled that we are stopped and thus we should // implicitly exit this peer's goroutine. return } } }