crypto: Refactor to move files out of the top level directory

Currently the top level directory contains basically all of the code
for the crypto package. This PR moves the crypto code into submodules
in a similar manner to what `golang/x/crypto` does. This improves code
organization.

Ref discussion: https://github.com/tendermint/tendermint/pull/1966

Closes #1956

tools/tm-bench/transacter.go

@@ -36,7 +36,8 @@ type transacter struct {
 
 	conns       []*websocket.Conn
 	connsBroken []bool
-	wg          sync.WaitGroup
+	startingWg  sync.WaitGroup
+	endingWg    sync.WaitGroup
 	stopped     bool
 
 	logger log.Logger
@@ -75,19 +76,22 @@ func (t *transacter) Start() error {
 		t.conns[i] = c
 	}
 
-	t.wg.Add(2 * t.Connections)
+	t.startingWg.Add(t.Connections)
+	t.endingWg.Add(2 * t.Connections)
 	for i := 0; i < t.Connections; i++ {
 		go t.sendLoop(i)
 		go t.receiveLoop(i)
 	}
 
+	t.startingWg.Wait()
+
 	return nil
 }
 
 // Stop closes the connections.
 func (t *transacter) Stop() {
 	t.stopped = true
-	t.wg.Wait()
+	t.endingWg.Wait()
 	for _, c := range t.conns {
 		c.Close()
 	}
@@ -97,7 +101,7 @@ func (t *transacter) Stop() {
 // `broadcast_tx_async`).
 func (t *transacter) receiveLoop(connIndex int) {
 	c := t.conns[connIndex]
-	defer t.wg.Done()
+	defer t.endingWg.Done()
 	for {
 		_, _, err := c.ReadMessage()
 		if err != nil {
@@ -118,6 +122,13 @@ func (t *transacter) receiveLoop(connIndex int) {
 
 // sendLoop generates transactions at a given rate.
 func (t *transacter) sendLoop(connIndex int) {
+	started := false
+	// Close the starting waitgroup, in the event that this fails to start
+	defer func() {
+		if !started {
+			t.startingWg.Done()
+		}
+	}()
 	c := t.conns[connIndex]
 
 	c.SetPingHandler(func(message string) error {
@@ -139,7 +150,7 @@ func (t *transacter) sendLoop(connIndex int) {
 	defer func() {
 		pingsTicker.Stop()
 		txsTicker.Stop()
-		t.wg.Done()
+		t.endingWg.Done()
 	}()
 
 	// hash of the host name is a part of each tx
@@ -149,6 +160,11 @@ func (t *transacter) sendLoop(connIndex int) {
 		hostname = "127.0.0.1"
 	}
 	hostnameHash = md5.Sum([]byte(hostname))
+	// each transaction embeds connection index, tx number and hash of the hostname
+	// we update the tx number between successive txs
+	tx := generateTx(connIndex, txNumber, t.Size, hostnameHash)
+	txHex := make([]byte, len(tx)*2)
+	hex.Encode(txHex, tx)
 
 	for {
 		select {
@@ -156,18 +172,23 @@ func (t *transacter) sendLoop(connIndex int) {
 			startTime := time.Now()
 			endTime := startTime.Add(time.Second)
 			numTxSent := t.Rate
+			if !started {
+				t.startingWg.Done()
+				started = true
+			}
 
+			now := time.Now()
 			for i := 0; i < t.Rate; i++ {
-				// each transaction embeds connection index, tx number and hash of the hostname
-				tx := generateTx(connIndex, txNumber, t.Size, hostnameHash)
-				paramsJSON, err := json.Marshal(map[string]interface{}{"tx": hex.EncodeToString(tx)})
+				// update tx number of the tx, and the corresponding hex
+				updateTx(tx, txHex, txNumber)
+				paramsJSON, err := json.Marshal(map[string]interface{}{"tx": txHex})
 				if err != nil {
 					fmt.Printf("failed to encode params: %v\n", err)
 					os.Exit(1)
 				}
 				rawParamsJSON := json.RawMessage(paramsJSON)
 
-				c.SetWriteDeadline(time.Now().Add(sendTimeout))
+				c.SetWriteDeadline(now.Add(sendTimeout))
 				err = c.WriteJSON(rpctypes.RPCRequest{
 					JSONRPC: "2.0",
 					ID:      "tm-bench",
@@ -182,9 +203,10 @@ func (t *transacter) sendLoop(connIndex int) {
 					return
 				}
 
-				// Time added here is 7.13 ns/op, not significant enough to worry about
-				if i%20 == 0 {
-					if time.Now().After(endTime) {
+				// cache the time.Now() reads to save time.
+				if i%5 == 0 {
+					now = time.Now()
+					if now.After(endTime) {
 						// Plus one accounts for sending this tx
 						numTxSent = i + 1
 						break
@@ -250,3 +272,13 @@ func generateTx(connIndex int, txNumber int, txSize int, hostnameHash [md5.Size]
 
 	return tx
 }
+
+// warning, mutates input byte slice
+func updateTx(tx []byte, txHex []byte, txNumber int) {
+	binary.PutUvarint(tx[8:16], uint64(txNumber))
+	hexUpdate := make([]byte, 16)
+	hex.Encode(hexUpdate, tx[8:16])
+	for i := 16; i < 32; i++ {
+		txHex[i] = hexUpdate[i-16]
+	}
+}