Fix bugs and add SendTransaction, which isn't that great.

spvsvc/spvchain/query.go

@@ -3,6 +3,8 @@
 package spvchain
 
 import (
+	"fmt"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -207,7 +209,8 @@ func (s *ChainService) queryPeers(
 					// to the channel if we quit before
 					// reading the channel.
 					sentChan := make(chan struct{}, 1)
-					sp.QueueMessage(queryMsg, sentChan)
+					sp.QueueMessageWithEncoding(queryMsg,
+						sentChan, wire.WitnessEncoding)
 					select {
 					case <-sentChan:
 					case <-quit:
@@ -279,7 +282,7 @@ checkResponses:
 // GetCFilter gets a cfilter from the database. Failing that, it requests the
 // cfilter from the network and writes it to the database.
 func (s *ChainService) GetCFilter(blockHash chainhash.Hash,
-	extended bool, options ...QueryOption) *gcs.Filter {
+	extended bool, options ...QueryOption) (*gcs.Filter, error) {
 	getFilter := s.GetBasicFilter
 	getHeader := s.GetBasicHeader
 	putFilter := s.putBasicFilter
@@ -290,22 +293,34 @@ func (s *ChainService) GetCFilter(blockHash chainhash.Hash,
 	}
 	filter, err := getFilter(blockHash)
 	if err == nil && filter != nil {
-		return filter
+		return filter, nil
 	}
 	// We didn't get the filter from the DB, so we'll set it to nil and try
 	// to get it from the network.
 	filter = nil
 	block, _, err := s.GetBlockByHash(blockHash)
-	if err != nil || block.BlockHash() != blockHash {
+	if err != nil {
-		return nil
+		return nil, err
+	}
+	if block.BlockHash() != blockHash {
+		return nil, fmt.Errorf("Couldn't get header for block %s "+
+			"from database", blockHash)
 	}
 	curHeader, err := getHeader(blockHash)
 	if err != nil {
-		return nil
+		return nil, fmt.Errorf("Couldn't get cfheader for block %s "+
+			"from database", blockHash)
 	}
 	prevHeader, err := getHeader(block.PrevBlock)
 	if err != nil {
-		return nil
+		return nil, fmt.Errorf("Couldn't get cfheader for block %s "+
+			"from database", blockHash)
+	}
+	// If we're expecting a zero filter, just return a nil filter and don't
+	// bother trying to get it from the network. The caller will know
+	// there's no error because we're also returning a nil error.
+	if builder.MakeHeaderForFilter(nil, *prevHeader) == *curHeader {
+		return nil, nil
 	}
 	s.queryPeers(
 		// Send a wire.GetCFilterMsg
@@ -364,19 +379,21 @@ func (s *ChainService) GetCFilter(blockHash chainhash.Hash,
 		log.Tracef("Wrote filter for block %s, extended: %t",
 			blockHash, extended)
 	}
-	return filter
+	return filter, nil
 }
 
 // GetBlockFromNetwork gets a block by requesting it from the network, one peer
 // at a time, until one answers.
 func (s *ChainService) GetBlockFromNetwork(
-	blockHash chainhash.Hash, options ...QueryOption) *btcutil.Block {
+	blockHash chainhash.Hash, options ...QueryOption) (*btcutil.Block,
+	error) {
 	blockHeader, height, err := s.GetBlockByHash(blockHash)
 	if err != nil || blockHeader.BlockHash() != blockHash {
-		return nil
+		return nil, fmt.Errorf("Couldn't get header for block %s "+
+			"from database", blockHash)
 	}
 	getData := wire.NewMsgGetData()
-	getData.AddInvVect(wire.NewInvVect(wire.InvTypeBlock,
+	getData.AddInvVect(wire.NewInvVect(wire.InvTypeWitnessBlock,
 		&blockHash))
 	// The block is only updated from the checkResponse function argument,
 	// which is always called single-threadedly. We don't check the block
@@ -441,5 +458,37 @@ func (s *ChainService) GetBlockFromNetwork(
 		},
 		options...,
 	)
-	return foundBlock
+	if foundBlock == nil {
+		return nil, fmt.Errorf("Couldn't retrieve block %s from "+
+			"network", blockHash)
+	}
+	return foundBlock, nil
+}
+
+// SendTransaction sends a transaction to each peer. It returns an error if any
+// peer rejects the transaction for any reason than that it's already known.
+// TODO: Better privacy by sending to only one random peer and watching
+// propagation, requires better peer selection support in query API.
+func (s *ChainService) SendTransaction(tx *wire.MsgTx,
+	options ...QueryOption) error {
+	var err error
+	s.queryPeers(
+		tx,
+		func(sp *serverPeer, resp wire.Message, quit chan<- struct{}) {
+			switch response := resp.(type) {
+			case *wire.MsgReject:
+				if response.Hash == tx.TxHash() &&
+					!strings.Contains(response.Reason,
+						"already have transaction") {
+					err = log.Errorf("Transaction %s "+
+						"rejected by %s: %s",
+						tx.TxHash(), sp.Addr(),
+						response.Reason)
+					close(quit)
+				}
+			}
+		},
+		options...,
+	)
+	return err
 }

spvsvc/spvchain/rescan.go

@@ -320,7 +320,10 @@ rescanLoop:
 		var err error
 		key := builder.DeriveKey(&curStamp.Hash)
 		matched := false
-		bFilter = s.GetCFilter(curStamp.Hash, false)
+		bFilter, err = s.GetCFilter(curStamp.Hash, false)
+		if err != nil {
+			return err
+		}
 		if bFilter != nil && bFilter.N() != 0 {
 			// We see if any relevant transactions match.
 			matched, err = bFilter.MatchAny(key, watchList)
@@ -329,7 +332,10 @@ rescanLoop:
 			}
 		}
 		if len(ro.watchTXIDs) > 0 {
-			eFilter = s.GetCFilter(curStamp.Hash, true)
+			eFilter, err = s.GetCFilter(curStamp.Hash, true)
+			if err != nil {
+				return err
+			}
 		}
 		if eFilter != nil && eFilter.N() != 0 {
 			// We see if any relevant transactions match.
@@ -345,11 +351,14 @@ rescanLoop:
 			// We've matched. Now we actually get the block
 			// and cycle through the transactions to see
 			// which ones are relevant.
-			block = s.GetBlockFromNetwork(
+			block, err = s.GetBlockFromNetwork(
 				curStamp.Hash, ro.queryOptions...)
+			if err != nil {
+				return err
+			}
 			if block == nil {
-				return fmt.Errorf("Couldn't get block "+
+				return fmt.Errorf("Couldn't get block %d "+
-					"%d (%s)", curStamp.Height,
+					"(%s) from network", curStamp.Height,
 					curStamp.Hash)
 			}
 			relevantTxs, err = notifyBlock(block,
@@ -409,9 +418,7 @@ func notifyBlock(block *btcutil.Block, outPoints *[]wire.OutPoint,
 			}
 		}
 		for outIdx, out := range tx.MsgTx().TxOut {
-			pushedData, err :=
+			pushedData, err := txscript.PushedData(out.PkScript)
-				txscript.PushedData(
-					out.PkScript)
 			if err != nil {
 				continue
 			}
@@ -503,42 +510,51 @@ func (s *ChainService) GetUtxo(options ...RescanOption) (*wire.TxOut, error) {
 		}
 	}
 	log.Tracef("Starting scan for output spend from known block %d (%s) "+
-		"back to block %d (%s)", curStamp.Height, curStamp.Hash)
+		"back to block %d (%s)", curStamp.Height, curStamp.Hash,
+		ro.startBlock.Height, ro.startBlock.Hash)
 
 	for {
 		// Check the basic filter for the spend and the extended filter
 		// for the transaction in which the outpout is funded.
-		filter := s.GetCFilter(curStamp.Hash, false,
+		filter, err := s.GetCFilter(curStamp.Hash, false,
 			ro.queryOptions...)
-		if filter == nil {
+		if err != nil {
 			return nil, fmt.Errorf("Couldn't get basic filter for "+
 				"block %d (%s)", curStamp.Height, curStamp.Hash)
 		}
-		matched, err := filter.MatchAny(builder.DeriveKey(
+		matched := false
+		if filter != nil {
+			matched, err = filter.MatchAny(builder.DeriveKey(
 				&curStamp.Hash), watchList)
+		}
 		if err != nil {
 			return nil, err
 		}
 		if !matched {
-			filter = s.GetCFilter(curStamp.Hash, true,
+			filter, err = s.GetCFilter(curStamp.Hash, true,
 				ro.queryOptions...)
-			if filter == nil {
+			if err != nil {
 				return nil, fmt.Errorf("Couldn't get extended "+
 					"filter for block %d (%s)",
 					curStamp.Height, curStamp.Hash)
 			}
-			matched, err = filter.MatchAny(builder.DeriveKey(
+			if filter != nil {
-				&curStamp.Hash), watchList)
+				matched, err = filter.MatchAny(
+					builder.DeriveKey(&curStamp.Hash),
+					watchList)
+			}
 		}
 		// If either is matched, download the block and check to see
 		// what we have.
 		if matched {
-			block := s.GetBlockFromNetwork(curStamp.Hash,
+			block, err := s.GetBlockFromNetwork(curStamp.Hash,
 				ro.queryOptions...)
+			if err != nil {
+				return nil, err
+			}
 			if block == nil {
-				return nil, fmt.Errorf("Couldn't get "+
+				return nil, fmt.Errorf("Couldn't get block %d "+
-					"block %d (%s)",
+					"(%s)", curStamp.Height, curStamp.Hash)
-					curStamp.Height, curStamp.Hash)
 			}
 			// If we've spent the output in this block, return an
 			// error stating that the output is spent.

spvsvc/spvchain/spvchain.go

@@ -21,7 +21,6 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcwallet/waddrmgr"
-	"github.com/btcsuite/btcwallet/wallet"
 	"github.com/btcsuite/btcwallet/walletdb"
 )
 
@@ -43,11 +42,11 @@ var (
 	UserAgentVersion = "0.0.1-alpha"
 
 	// Services describes the services that are supported by the server.
-	Services = wire.SFNodeCF
+	Services = wire.SFNodeWitness | wire.SFNodeCF
 
 	// RequiredServices describes the services that are required to be
 	// supported by outbound peers.
-	RequiredServices = wire.SFNodeNetwork | wire.SFNodeCF
+	RequiredServices = wire.SFNodeNetwork | wire.SFNodeWitness | wire.SFNodeCF
 
 	// BanThreshold is the maximum ban score before a peer is banned.
 	BanThreshold = uint32(100)
@@ -1052,33 +1051,6 @@ func disconnectPeer(peerList map[int32]*serverPeer, compareFunc func(*serverPeer
 	return false
 }
 
-// sendUnminedTxs iterates through all transactions that spend from wallet
-// credits that are not known to have been mined into a block, and attempts to
-// send each to the chain server for relay.
-//
-// TODO: This should return an error if any of these lookups or sends fail, but
-// since send errors due to double spends need to be handled gracefully and this
-// isn't done yet, all sending errors are simply logged.
-func (s *ChainService) sendUnminedTxs(w *wallet.Wallet) error {
-	/*txs, err := w.TxStore.UnminedTxs()
-	if err != nil {
-		return err
-	}
-	rpcClient := s.rpcClient
-	for _, tx := range txs {
-		resp, err := rpcClient.SendRawTransaction(tx, false)
-		if err != nil {
-			// TODO(jrick): Check error for if this tx is a double spend,
-			// remove it if so.
-			log.Debugf("Could not resend transaction %v: %v",
-				tx.TxHash(), err)
-			continue
-		}
-		log.Debugf("Resent unmined transaction %v", resp)
-	}*/
-	return nil
-}
-
 // PublishTransaction sends the transaction to the consensus RPC server so it
 // can be propigated to other nodes and eventually mined.
 func (s *ChainService) PublishTransaction(tx *wire.MsgTx) error {
@@ -1087,31 +1059,6 @@ func (s *ChainService) PublishTransaction(tx *wire.MsgTx) error {
 	return nil
 }
 
-// AnnounceNewTransactions generates and relays inventory vectors and notifies
-// both websocket and getblocktemplate long poll clients of the passed
-// transactions.  This function should be called whenever new transactions
-// are added to the mempool.
-func (s *ChainService) AnnounceNewTransactions( /*newTxs []*mempool.TxDesc*/ ) {
-	// Generate and relay inventory vectors for all newly accepted
-	// transactions into the memory pool due to the original being
-	// accepted.
-	/*for _, txD := range newTxs {
-		// Generate the inventory vector and relay it.
-		iv := wire.NewInvVect(wire.InvTypeTx, txD.Tx.Hash())
-		s.RelayInventory(iv, txD)
-
-		if s.rpcServer != nil {
-			// Notify websocket clients about mempool transactions.
-			s.rpcServer.ntfnMgr.NotifyMempoolTx(txD.Tx, true)
-
-			// Potentially notify any getblocktemplate long poll clients
-			// about stale block templates due to the new transaction.
-			s.rpcServer.gbtWorkState.NotifyMempoolTx(
-				s.txMemPool.LastUpdated())
-		}
-	}*/
-}
-
 // newPeerConfig returns the configuration for the given serverPeer.
 func newPeerConfig(sp *serverPeer) *peer.Config {
 	return &peer.Config{
@@ -1189,64 +1136,6 @@ func (s *ChainService) UpdatePeerHeights(latestBlkHash *chainhash.Hash, latestHe
 	}
 }
 
-// rebroadcastHandler keeps track of user submitted inventories that we have
-// sent out but have not yet made it into a block. We periodically rebroadcast
-// them in case our peers restarted or otherwise lost track of them.
-func (s *ChainService) rebroadcastHandler() {
-	// Wait 5 min before first tx rebroadcast.
-	timer := time.NewTimer(5 * time.Minute)
-	//pendingInvs := make(map[wire.InvVect]interface{})
-
-out:
-	for {
-		select {
-		/*case riv := <-s.modifyRebroadcastInv:
-		switch msg := riv.(type) {
-		// Incoming InvVects are added to our map of RPC txs.
-		case broadcastInventoryAdd:
-			pendingInvs[*msg.invVect] = msg.data
-
-		// When an InvVect has been added to a block, we can
-		// now remove it, if it was present.
-		case broadcastInventoryDel:
-			if _, ok := pendingInvs[*msg]; ok {
-				delete(pendingInvs, *msg)
-			}
-		}*/
-
-		case <-timer.C: /*
-				// Any inventory we have has not made it into a block
-				// yet. We periodically resubmit them until they have.
-				for iv, data := range pendingInvs {
-					ivCopy := iv
-					s.RelayInventory(&ivCopy, data)
-				}
-
-				// Process at a random time up to 30mins (in seconds)
-				// in the future.
-				timer.Reset(time.Second *
-					time.Duration(randomUint16Number(1800))) */
-
-		case <-s.quit:
-			break out
-		}
-	}
-
-	timer.Stop()
-
-	// Drain channels before exiting so nothing is left waiting around
-	// to send.
-	/*cleanup:
-	for {
-		select {
-		//case <-s.modifyRebroadcastInv:
-		default:
-			break cleanup
-		}
-	}*/
-	s.wg.Done()
-}
-
 // ChainParams returns a copy of the ChainService's chaincfg.Params.
 func (s *ChainService) ChainParams() chaincfg.Params {
 	return s.chainParams
@@ -1261,10 +1150,8 @@ func (s *ChainService) Start() {
 
 	// Start the peer handler which in turn starts the address and block
 	// managers.
-	s.wg.Add(2)
+	s.wg.Add(1)
 	go s.peerHandler()
-	go s.rebroadcastHandler()
-
 }
 
 // Stop gracefully shuts down the server by stopping and disconnecting all

spvsvc/spvchain/sync_test.go

@@ -23,6 +23,7 @@ import (
 	"github.com/btcsuite/btclog"
 	"github.com/btcsuite/btcrpcclient"
 	"github.com/btcsuite/btcutil"
+	"github.com/btcsuite/btcutil/gcs"
 	"github.com/btcsuite/btcutil/gcs/builder"
 	"github.com/btcsuite/btcwallet/spvsvc/spvchain"
 	"github.com/btcsuite/btcwallet/waddrmgr"
@@ -37,7 +38,7 @@ var (
 	// log messages from the tests themselves as well. Keep in mind some
 	// log messages may not appear in order due to use of multiple query
 	// goroutines in the tests.
-	logLevel    = btclog.Off
+	logLevel    = btclog.TraceLvl
 	syncTimeout = 30 * time.Second
 	syncUpdate  = time.Second
 	// Don't set this too high for your platform, or the tests will miss
@@ -323,10 +324,8 @@ func TestSetup(t *testing.T) {
 		},
 	}
 
-	spvchain.Services = 0
 	spvchain.MaxPeers = 3
 	spvchain.BanDuration = 5 * time.Second
-	spvchain.RequiredServices = wire.SFNodeNetwork
 	spvchain.WaitForMoreCFHeaders = time.Second
 	svc, err := spvchain.NewChainService(config)
 	if err != nil {
@@ -341,14 +340,6 @@ func TestSetup(t *testing.T) {
 		t.Fatalf("Couldn't sync ChainService: %s", err)
 	}
 
-	// Test that we can get blocks and cfilters via P2P and decide which are
-	// valid and which aren't.
-	// TODO: Split this out into a benchmark.
-	err = testRandomBlocks(t, svc, h1)
-	if err != nil {
-		t.Fatalf("Testing blocks and cfilters failed: %s", err)
-	}
-
 	// Generate an address and send it some coins on the h1 chain. We use
 	// this to test rescans and notifications.
 	secSrc := newSecSource(&modParams)
@@ -568,9 +559,10 @@ func TestSetup(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Couldn't sign transaction: %s", err)
 	}
-	_, err = h1.Node.SendRawTransaction(authTx1.Tx, true)
+	banPeer(svc, h2)
+	err = svc.SendTransaction(authTx1.Tx, queryOptions...)
 	if err != nil {
-		t.Fatalf("Unable to send raw transaction to node: %s", err)
+		t.Fatalf("Unable to send transaction to network: %s", err)
 	}
 	_, err = h1.Node.Generate(1)
 	if err != nil {
@@ -604,9 +596,10 @@ func TestSetup(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Couldn't sign transaction: %s", err)
 	}
-	_, err = h1.Node.SendRawTransaction(authTx2.Tx, true)
+	banPeer(svc, h2)
+	err = svc.SendTransaction(authTx2.Tx, queryOptions...)
 	if err != nil {
-		t.Fatalf("Unable to send raw transaction to node: %s", err)
+		t.Fatalf("Unable to send transaction to network: %s", err)
 	}
 	_, err = h1.Node.Generate(1)
 	if err != nil {
@@ -621,10 +614,14 @@ func TestSetup(t *testing.T) {
 		t.Fatalf("Wrong number of relevant transactions. Want: 4, got:"+
 			" %d", numTXs)
 	}
-	// Generate 1 blocks on h1, one at a time, to make sure the
+	// Generate a block with a nonstandard coinbase to generate a basic
-	// ChainService instance stays caught up.
+	// filter with 0 entries.
-	for i := 0; i < 1; i++ {
+	_, err = h1.GenerateAndSubmitBlockWithCustomCoinbaseOutputs(
-		_, err = h1.Node.Generate(1)
+		[]*btcutil.Tx{}, rpctest.BlockVersion, time.Time{},
+		[]wire.TxOut{{
+			Value:    0,
+			PkScript: []byte{},
+		}})
 	if err != nil {
 		t.Fatalf("Couldn't generate/submit block: %s", err)
 	}
@@ -632,7 +629,6 @@ func TestSetup(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Couldn't sync ChainService: %s", err)
 	}
-	}
 
 	// Check and make sure the previous UTXO is now spent.
 	_, err = svc.GetUtxo(
@@ -644,8 +640,17 @@ func TestSetup(t *testing.T) {
 		t.Fatalf("UTXO %s not seen as spent: %s", ourOutPoint, err)
 	}
 
+	// Test that we can get blocks and cfilters via P2P and decide which are
+	// valid and which aren't.
+	// TODO: Split this out into a benchmark.
+	err = testRandomBlocks(t, svc, h1)
+	if err != nil {
+		t.Fatalf("Testing blocks and cfilters failed: %s", err)
+	}
+
 	// Generate 5 blocks on h2 and wait for ChainService to sync to the
-	// newly-best chain on h2.
+	// newly-best chain on h2. This includes the transactions sent via
+	// svc.SendTransaction earlier, so we'll have to
 	_, err = h2.Node.Generate(5)
 	if err != nil {
 		t.Fatalf("Couldn't generate/submit blocks: %s", err)
@@ -913,8 +918,12 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 				return
 			}
 			// Get block from network.
-			haveBlock := svc.GetBlockFromNetwork(blockHash,
+			haveBlock, err := svc.GetBlockFromNetwork(blockHash,
 				queryOptions...)
+			if err != nil {
+				errChan <- err
+				return
+			}
 			if haveBlock == nil {
 				errChan <- fmt.Errorf("Couldn't get block %d "+
 					"(%s) from network", height, blockHash)
@@ -939,11 +948,10 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 				return
 			}
 			// Get basic cfilter from network.
-			haveFilter := svc.GetCFilter(blockHash, false,
+			haveFilter, err := svc.GetCFilter(blockHash, false,
 				queryOptions...)
-			if haveFilter == nil {
+			if err != nil {
-				errChan <- fmt.Errorf("Couldn't get basic "+
+				errChan <- err
-					"filter for block %d", height)
 				return
 			}
 			// Get basic cfilter from RPC.
@@ -956,7 +964,11 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 				return
 			}
 			// Check that network and RPC cfilters match.
-			if !bytes.Equal(haveFilter.NBytes(), wantFilter.Data) {
+			var haveBytes []byte
+			if haveFilter != nil {
+				haveBytes = haveFilter.NBytes()
+			}
+			if !bytes.Equal(haveBytes, wantFilter.Data) {
 				errChan <- fmt.Errorf("Basic filter from P2P "+
 					"network/DB doesn't match RPC value "+
 					"for block %d", height)
@@ -965,7 +977,7 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 			// Calculate basic filter from block.
 			calcFilter, err := builder.BuildBasicFilter(
 				haveBlock.MsgBlock())
-			if err != nil {
+			if err != nil && err != gcs.ErrNoData {
 				errChan <- fmt.Errorf("Couldn't build basic "+
 					"filter for block %d (%s): %s", height,
 					blockHash, err)
@@ -973,7 +985,7 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 			}
 			// Check that the network value matches the calculated
 			// value from the block.
-			if !reflect.DeepEqual(*haveFilter, *calcFilter) {
+			if !reflect.DeepEqual(haveFilter, calcFilter) {
 				errChan <- fmt.Errorf("Basic filter from P2P "+
 					"network/DB doesn't match calculated "+
 					"value for block %d", height)
@@ -1007,11 +1019,10 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 				return
 			}
 			// Get extended cfilter from network
-			haveFilter = svc.GetCFilter(blockHash, true,
+			haveFilter, err = svc.GetCFilter(blockHash, true,
 				queryOptions...)
-			if haveFilter == nil {
+			if err != nil {
-				errChan <- fmt.Errorf("Couldn't get extended "+
+				errChan <- err
-					"filter for block %d", height)
 				return
 			}
 			// Get extended cfilter from RPC
@@ -1024,7 +1035,10 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 				return
 			}
 			// Check that network and RPC cfilters match
-			if !bytes.Equal(haveFilter.NBytes(), wantFilter.Data) {
+			if haveFilter != nil {
+				haveBytes = haveFilter.NBytes()
+			}
+			if !bytes.Equal(haveBytes, wantFilter.Data) {
 				errChan <- fmt.Errorf("Extended filter from "+
 					"P2P network/DB doesn't match RPC "+
 					"value for block %d", height)
@@ -1033,7 +1047,7 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 			// Calculate extended filter from block
 			calcFilter, err = builder.BuildExtFilter(
 				haveBlock.MsgBlock())
-			if err != nil {
+			if err != nil && err != gcs.ErrNoData {
 				errChan <- fmt.Errorf("Couldn't build extended"+
 					" filter for block %d (%s): %s", height,
 					blockHash, err)
@@ -1041,7 +1055,7 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 			}
 			// Check that the network value matches the calculated
 			// value from the block.
-			if !reflect.DeepEqual(*haveFilter, *calcFilter) {
+			if !reflect.DeepEqual(haveFilter, calcFilter) {
 				errChan <- fmt.Errorf("Extended filter from "+
 					"P2P network/DB doesn't match "+
 					"calculated value for block %d", height)
@@ -1104,76 +1118,108 @@ func testRandomBlocks(t *testing.T, svc *spvchain.ChainService,
 // notifications continue until the `quit` channel is closed.
 func startRescan(t *testing.T, svc *spvchain.ChainService, addr btcutil.Address,
 	startBlock *waddrmgr.BlockStamp, quit <-chan struct{}) error {
-	go svc.Rescan(
+	go func() {
+		err := svc.Rescan(
 			spvchain.QuitChan(quit),
 			spvchain.WatchAddrs(addr),
 			spvchain.StartBlock(startBlock),
-		spvchain.NotificationHandlers(btcrpcclient.NotificationHandlers{
+			spvchain.NotificationHandlers(
-			OnBlockConnected: func(hash *chainhash.Hash,
+				btcrpcclient.NotificationHandlers{
+					OnBlockConnected: func(
+						hash *chainhash.Hash,
 						height int32, time time.Time) {
 						rescanMtx.Lock()
-				gotLog = append(gotLog, []byte("bc")...)
+						gotLog = append(gotLog,
+							[]byte("bc")...)
 						curBlockHeight = height
 						rescanMtx.Unlock()
 					},
-			OnBlockDisconnected: func(hash *chainhash.Hash,
+					OnBlockDisconnected: func(
+						hash *chainhash.Hash,
 						height int32, time time.Time) {
 						rescanMtx.Lock()
 						delete(ourKnownTxsByBlock, *hash)
-				gotLog = append(gotLog, []byte("bd")...)
+						gotLog = append(gotLog,
+							[]byte("bd")...)
 						curBlockHeight = height - 1
 						rescanMtx.Unlock()
 					},
 					OnRecvTx: func(tx *btcutil.Tx,
 						details *btcjson.BlockDetails) {
 						rescanMtx.Lock()
-				hash, err := chainhash.NewHashFromStr(
+						hash, err := chainhash.
+							NewHashFromStr(
 								details.Hash)
 						if err != nil {
-					t.Errorf("Couldn't decode hash %s: %s",
+							t.Errorf("Couldn't "+
-						details.Hash, err)
+								"decode hash "+
+								"%s: %s",
+								details.Hash,
+								err)
 						}
 						ourKnownTxsByBlock[*hash] = append(
-					ourKnownTxsByBlock[*hash], tx)
+							ourKnownTxsByBlock[*hash],
-				gotLog = append(gotLog, []byte("rv")...)
+							tx)
+						gotLog = append(gotLog,
+							[]byte("rv")...)
 						rescanMtx.Unlock()
 					},
 					OnRedeemingTx: func(tx *btcutil.Tx,
 						details *btcjson.BlockDetails) {
 						rescanMtx.Lock()
-				hash, err := chainhash.NewHashFromStr(
+						hash, err := chainhash.
+							NewHashFromStr(
 								details.Hash)
 						if err != nil {
-					t.Errorf("Couldn't decode hash %s: %s",
+							t.Errorf("Couldn't "+
-						details.Hash, err)
+								"decode hash "+
+								"%s: %s",
+								details.Hash,
+								err)
 						}
 						ourKnownTxsByBlock[*hash] = append(
-					ourKnownTxsByBlock[*hash], tx)
+							ourKnownTxsByBlock[*hash],
-				gotLog = append(gotLog, []byte("rd")...)
+							tx)
+						gotLog = append(gotLog,
+							[]byte("rd")...)
 						rescanMtx.Unlock()
 					},
-			OnFilteredBlockConnected: func(height int32,
+					OnFilteredBlockConnected: func(
+						height int32,
 						header *wire.BlockHeader,
 						relevantTxs []*btcutil.Tx) {
 						rescanMtx.Lock()
 						ourKnownTxsByFilteredBlock[header.BlockHash()] =
 							relevantTxs
-				gotLog = append(gotLog, []byte("fc")...)
+						gotLog = append(gotLog,
-				gotLog = append(gotLog, uint8(len(relevantTxs)))
+							[]byte("fc")...)
+						gotLog = append(gotLog,
+							uint8(len(relevantTxs)))
 						curFilteredBlockHeight = height
 						rescanMtx.Unlock()
 					},
-			OnFilteredBlockDisconnected: func(height int32,
+					OnFilteredBlockDisconnected: func(
+						height int32,
 						header *wire.BlockHeader) {
 						rescanMtx.Lock()
 						delete(ourKnownTxsByFilteredBlock,
 							header.BlockHash())
-				gotLog = append(gotLog, []byte("fd")...)
+						gotLog = append(gotLog,
-				curFilteredBlockHeight = height - 1
+							[]byte("fd")...)
+						curFilteredBlockHeight =
+							height - 1
 						rescanMtx.Unlock()
 					},
 				}),
 		)
+		if logLevel != btclog.Off {
+			if err != nil {
+				t.Logf("Rescan ended: %s", err)
+			} else {
+				t.Logf("Rescan ended successfully")
+			}
+		}
+	}()
 	return nil
 }
 
@@ -1203,3 +1249,15 @@ func checkRescanStatus() (int, int32, error) {
 	}
 	return txCount[0], curBlockHeight, nil
 }
+
+// banPeer bans and disconnects the requested harness from the ChainService
+// instance for BanDuration seconds.
+func banPeer(svc *spvchain.ChainService, harness *rpctest.Harness) {
+	peers := svc.Peers()
+	for _, peer := range peers {
+		if peer.Addr() == harness.P2PAddress() {
+			svc.BanPeer(peer)
+			peer.Disconnect()
+		}
+	}
+}