mempool no gossip back (#2778)

Closes #1798 This is done by making every mempool tx maintain a list of peers who its received the tx from. Instead of using the 20byte peer ID, it instead uses a local map from peerID to uint16 counter, so every peer adds 2 bytes. (Word aligned to probably make it 8 bytes) This also required resetting the callback function on every CheckTx. This likely has performance ramifications for instruction caching. The actual setting operation isn't costly with the removal of defers in this PR. * Make the mempool not gossip txs back to peers its received it from * Fix adversarial memleak * Don't break interface * Update changelog * Forgot to add a mtx * forgot a mutex * Update mempool/reactor.go Co-Authored-By: ValarDragon <ValarDragon@users.noreply.github.com> * Update mempool/mempool.go Co-Authored-By: ValarDragon <ValarDragon@users.noreply.github.com> * Use unknown peer ID Co-Authored-By: ValarDragon <ValarDragon@users.noreply.github.com> * fix compilation * use next wait chan logic when skipping * Minor fixes * Add TxInfo * Add reverse map * Make activeID's auto-reserve 0 * 0 -> UnknownPeerID Co-Authored-By: ValarDragon <ValarDragon@users.noreply.github.com> * Switch to making the normal case set a callback on the reqres object The recheck case is still done via the global callback, and stats are also set via global callback * fix merge conflict * Addres comments * Add cache tests * add cache tests * minor fixes * update metrics in reqResCb and reformat code * goimport -w mempool/reactor.go * mempool: update memTx senders I had to introduce txsMap for quick mempoolTx lookups. * change senders type from []uint16 to sync.Map Fixes DATA RACE: ``` Read at 0x00c0013fcd3a by goroutine 183: github.com/tendermint/tendermint/mempool.(*MempoolReactor).broadcastTxRoutine() /go/src/github.com/tendermint/tendermint/mempool/reactor.go:195 +0x3c7 Previous write at 0x00c0013fcd3a by D[2019-02-27|10:10:49.058] Read PacketMsg switch=3 peer=35bc1e3558c182927b31987eeff3feb3d58a0fc5@127.0.0.1 :46552 conn=MConn{pipe} packet="PacketMsg{30:2B06579D0A143EB78F3D3299DE8213A51D4E11FB05ACE4D6A14F T:1}" goroutine 190: github.com/tendermint/tendermint/mempool.(*Mempool).CheckTxWithInfo() /go/src/github.com/tendermint/tendermint/mempool/mempool.go:387 +0xdc1 github.com/tendermint/tendermint/mempool.(*MempoolReactor).Receive() /go/src/github.com/tendermint/tendermint/mempool/reactor.go:134 +0xb04 github.com/tendermint/tendermint/p2p.createMConnection.func1() /go/src/github.com/tendermint/tendermint/p2p/peer.go:374 +0x25b github.com/tendermint/tendermint/p2p/conn.(*MConnection).recvRoutine() /go/src/github.com/tendermint/tendermint/p2p/conn/connection.go:599 +0xcce Goroutine 183 (running) created at: D[2019-02-27|10:10:49.058] Send switch=2 peer=1efafad5443abeea4b7a8155218e4369525d987e@127.0.0.1:46193 channel=48 conn=MConn{pipe} m sgBytes=2B06579D0A146194480ADAE00C2836ED7125FEE65C1D9DD51049 github.com/tendermint/tendermint/mempool.(*MempoolReactor).AddPeer() /go/src/github.com/tendermint/tendermint/mempool/reactor.go:105 +0x1b1 github.com/tendermint/tendermint/p2p.(*Switch).startInitPeer() /go/src/github.com/tendermint/tendermint/p2p/switch.go:683 +0x13b github.com/tendermint/tendermint/p2p.(*Switch).addPeer() /go/src/github.com/tendermint/tendermint/p2p/switch.go:650 +0x585 github.com/tendermint/tendermint/p2p.(*Switch).addPeerWithConnection() /go/src/github.com/tendermint/tendermint/p2p/test_util.go:145 +0x939 github.com/tendermint/tendermint/p2p.Connect2Switches.func2() /go/src/github.com/tendermint/tendermint/p2p/test_util.go:109 +0x50 I[2019-02-27|10:10:49.058] Added good transaction validator=0 tx=43B4D1F0F03460BD262835C4AA560DB860CFBBE85BD02386D83DAC38C67B3AD7 res="&{CheckTx:gas_w anted:1 }" height=0 total=375 Goroutine 190 (running) created at: github.com/tendermint/tendermint/p2p/conn.(*MConnection).OnStart() /go/src/github.com/tendermint/tendermint/p2p/conn/connection.go:210 +0x313 github.com/tendermint/tendermint/libs/common.(*BaseService).Start() /go/src/github.com/tendermint/tendermint/libs/common/service.go:139 +0x4df github.com/tendermint/tendermint/p2p.(*peer).OnStart() /go/src/github.com/tendermint/tendermint/p2p/peer.go:179 +0x56 github.com/tendermint/tendermint/libs/common.(*BaseService).Start() /go/src/github.com/tendermint/tendermint/libs/common/service.go:139 +0x4df github.com/tendermint/tendermint/p2p.(*peer).Start() <autogenerated>:1 +0x43 github.com/tendermint/tendermint/p2p.(*Switch).startInitPeer() ``` * explain the choice of a map DS for senders * extract ids pool/mapper to a separate struct * fix literal copies lock value from senders: sync.Map contains sync.Mutex * use sync.Map#LoadOrStore instead of Load * fixes after Ismail's review * rename resCbNormal to resCbFirstTime
tendermint · Mar 26, 2019 · 6de7eff · 6de7eff
1 parent 25a3c8b
commit 6de7eff
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diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
@@ -20,6 +20,8 @@
 
 ### IMPROVEMENTS:
 
+- [mempool] \#2778 No longer send txs back to peers who sent it to you
+
 ### BUG FIXES:
 
 - [blockchain] \#2699 update the maxHeight when a peer is removed
diff --git a/docs/spec/reactors/mempool/reactor.md b/docs/spec/reactors/mempool/reactor.md
@@ -12,3 +12,5 @@ for details.
 
 Sending incorrectly encoded data or data exceeding `maxMsgSize` will result
 in stopping the peer.
+
+The mempool will not send a tx back to any peer which it received it from.
diff --git a/mempool/bench_test.go b/mempool/bench_test.go
@@ -26,6 +26,19 @@ func BenchmarkReap(b *testing.B) {
 	}
 }
 
+func BenchmarkCheckTx(b *testing.B) {
+	app := kvstore.NewKVStoreApplication()
+	cc := proxy.NewLocalClientCreator(app)
+	mempool, cleanup := newMempoolWithApp(cc)
+	defer cleanup()
+
+	for i := 0; i < b.N; i++ {
+		tx := make([]byte, 8)
+		binary.BigEndian.PutUint64(tx, uint64(i))
+		mempool.CheckTx(tx, nil)
+	}
+}
+
 func BenchmarkCacheInsertTime(b *testing.B) {
 	cache := newMapTxCache(b.N)
 	txs := make([][]byte, b.N)

diff --git a/mempool/cache_test.go b/mempool/cache_test.go
@@ -0,0 +1,101 @@
+package mempool
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/tendermint/tendermint/abci/example/kvstore"
+	"github.com/tendermint/tendermint/proxy"
+	"github.com/tendermint/tendermint/types"
+)
+
+func TestCacheRemove(t *testing.T) {
+	cache := newMapTxCache(100)
+	numTxs := 10
+	txs := make([][]byte, numTxs)
+	for i := 0; i < numTxs; i++ {
+		// probability of collision is 2**-256
+		txBytes := make([]byte, 32)
+		rand.Read(txBytes)
+		txs[i] = txBytes
+		cache.Push(txBytes)
+		// make sure its added to both the linked list and the map
+		require.Equal(t, i+1, len(cache.map_))
+		require.Equal(t, i+1, cache.list.Len())
+	}
+	for i := 0; i < numTxs; i++ {
+		cache.Remove(txs[i])
+		// make sure its removed from both the map and the linked list
+		require.Equal(t, numTxs-(i+1), len(cache.map_))
+		require.Equal(t, numTxs-(i+1), cache.list.Len())
+	}
+}
+
+func TestCacheAfterUpdate(t *testing.T) {
+	app := kvstore.NewKVStoreApplication()
+	cc := proxy.NewLocalClientCreator(app)
+	mempool, cleanup := newMempoolWithApp(cc)
+	defer cleanup()
+
+	// reAddIndices & txsInCache can have elements > numTxsToCreate
+	// also assumes max index is 255 for convenience
+	// txs in cache also checks order of elements
+	tests := []struct {
+		numTxsToCreate int
+		updateIndices  []int
+		reAddIndices   []int
+		txsInCache     []int
+	}{
+		{1, []int{}, []int{1}, []int{1, 0}},    // adding new txs works
+		{2, []int{1}, []int{}, []int{1, 0}},    // update doesn't remove tx from cache
+		{2, []int{2}, []int{}, []int{2, 1, 0}}, // update adds new tx to cache
+		{2, []int{1}, []int{1}, []int{1, 0}},   // re-adding after update doesn't make dupe
+	}
+	for tcIndex, tc := range tests {
+		for i := 0; i < tc.numTxsToCreate; i++ {
+			tx := types.Tx{byte(i)}
+			err := mempool.CheckTx(tx, nil)
+			require.NoError(t, err)
+		}
+
+		updateTxs := []types.Tx{}
+		for _, v := range tc.updateIndices {
+			tx := types.Tx{byte(v)}
+			updateTxs = append(updateTxs, tx)
+		}
+		mempool.Update(int64(tcIndex), updateTxs, nil, nil)
+
+		for _, v := range tc.reAddIndices {
+			tx := types.Tx{byte(v)}
+			_ = mempool.CheckTx(tx, nil)
+		}
+
+		cache := mempool.cache.(*mapTxCache)
+		node := cache.list.Front()
+		counter := 0
+		for node != nil {
+			require.NotEqual(t, len(tc.txsInCache), counter,
+				"cache larger than expected on testcase %d", tcIndex)
+
+			nodeVal := node.Value.([sha256.Size]byte)
+			expectedBz := sha256.Sum256([]byte{byte(tc.txsInCache[len(tc.txsInCache)-counter-1])})
+			// Reference for reading the errors:
+			// >>> sha256('\x00').hexdigest()
+			// '6e340b9cffb37a989ca544e6bb780a2c78901d3fb33738768511a30617afa01d'
+			// >>> sha256('\x01').hexdigest()
+			// '4bf5122f344554c53bde2ebb8cd2b7e3d1600ad631c385a5d7cce23c7785459a'
+			// >>> sha256('\x02').hexdigest()
+			// 'dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986'
+
+			require.Equal(t, expectedBz, nodeVal, "Equality failed on index %d, tc %d", counter, tcIndex)
+			counter++
+			node = node.Next()
+		}
+		require.Equal(t, len(tc.txsInCache), counter,
+			"cache smaller than expected on testcase %d", tcIndex)
+		mempool.Flush()
+	}
+}