brontide: add new benchmark to measure allocs for header+body decrypt

brontide/bench_test.go

@@ -0,0 +1,66 @@
+package brontide
+
+import (
+	"bytes"
+	"math"
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func BenchmarkReadHeaderAndBody(t *testing.B) {
+	// Create a test connection, grabbing either side of the connection
+	// into local variables. If the initial crypto handshake fails, then
+	// we'll get a non-nil error here.
+	localConn, remoteConn, cleanUp, err := establishTestConnection()
+	require.NoError(t, err, "unable to establish test connection: %v", err)
+	defer cleanUp()
+
+	rand.Seed(time.Now().Unix())
+
+	noiseRemoteConn := remoteConn.(*Conn)
+	noiseLocalConn := localConn.(*Conn)
+
+	// Now that we have a local and remote side (to set up the initial
+	// handshake state, we'll have the remote side write out something
+	// similar to a large message in the protocol.
+	const pktSize = 60_000
+	msg := bytes.Repeat([]byte("a"), pktSize)
+	err = noiseRemoteConn.WriteMessage(msg)
+	require.NoError(t, err, "unable to write encrypted message: %v", err)
+
+	cipherHeader := noiseRemoteConn.noise.nextHeaderSend
+	cipherMsg := noiseRemoteConn.noise.nextBodySend
+
+	var (
+		benchErr error
+		msgBuf   [math.MaxUint16]byte
+	)
+
+	t.ReportAllocs()
+	t.ResetTimer()
+
+	nonceValue := noiseLocalConn.noise.recvCipher.nonce
+	for i := 0; i < t.N; i++ {
+		pktLen, benchErr := noiseLocalConn.noise.ReadHeader(
+			bytes.NewReader(cipherHeader),
+		)
+		require.NoError(
+			t, benchErr, "#%v: failed decryption: %v", i, benchErr,
+		)
+		_, benchErr = noiseLocalConn.noise.ReadBody(
+			bytes.NewReader(cipherMsg), msgBuf[:pktLen],
+		)
+		require.NoError(
+			t, benchErr, "#%v: failed decryption: %v", i, benchErr,
+		)
+
+		// We reset the internal nonce each time as otherwise, we'd
+		// continue to increment it which would cause a decryption
+		// failure.
+		noiseLocalConn.noise.recvCipher.nonce = nonceValue
+	}
+	require.NoError(t, benchErr)
+}