refactor-for-testability (#3)

Co-authored-by: jdl <jdl@desktop>
Co-authored-by: jdl <jdl@crumpington.com>
Reviewed-on: #3

peer/cipher-data_test.go

@@ -0,0 +1,141 @@
+package peer
+
+import (
+	"bytes"
+	"crypto/rand"
+	mrand "math/rand/v2"
+	"reflect"
+	"testing"
+)
+
+func TestDataCipher(t *testing.T) {
+	maxSizePlaintext := make([]byte, bufferSize-dataHeaderSize-dataCipherOverhead)
+	rand.Read(maxSizePlaintext)
+
+	testCases := [][]byte{
+		make([]byte, 0),
+		{1},
+		{255},
+		{1, 2, 3, 4, 5},
+		[]byte("Hello world"),
+		maxSizePlaintext,
+	}
+
+	for _, plaintext := range testCases {
+		h1 := header{
+			StreamID: dataStreamID,
+			Counter:  235153,
+			SourceIP: 4,
+			DestIP:   88,
+		}
+
+		encrypted := make([]byte, bufferSize)
+
+		dc1 := newDataCipher()
+		encrypted = dc1.Encrypt(h1, plaintext, encrypted)
+		h2 := header{}
+		h2.Parse(encrypted)
+
+		dc2 := newDataCipherFromKey(dc1.Key())
+
+		decrypted, ok := dc2.Decrypt(encrypted, make([]byte, bufferSize-dataHeaderSize))
+		if !ok {
+			t.Fatal(ok)
+		}
+
+		if !bytes.Equal(plaintext, decrypted) {
+			t.Fatal("not equal")
+		}
+
+		if !reflect.DeepEqual(h1, h2) {
+			t.Fatalf("%v != %v", h1, h2)
+		}
+	}
+}
+
+func TestDataCipher_ModifyCiphertext(t *testing.T) {
+	maxSizePlaintext := make([]byte, bufferSize-dataHeaderSize-dataCipherOverhead)
+	rand.Read(maxSizePlaintext)
+
+	testCases := [][]byte{
+		make([]byte, 0),
+		{1},
+		{255},
+		{1, 2, 3, 4, 5},
+		[]byte("Hello world"),
+		maxSizePlaintext,
+	}
+
+	for _, plaintext := range testCases {
+		h1 := header{
+			Counter:  235153,
+			SourceIP: 4,
+			DestIP:   88,
+		}
+
+		encrypted := make([]byte, bufferSize)
+
+		dc1 := newDataCipher()
+		encrypted = dc1.Encrypt(h1, plaintext, encrypted)
+		encrypted[mrand.IntN(len(encrypted))]++
+
+		dc2 := newDataCipherFromKey(dc1.Key())
+
+		_, ok := dc2.Decrypt(encrypted, make([]byte, bufferSize-dataHeaderSize))
+		if ok {
+			t.Fatal(ok)
+		}
+	}
+}
+
+func TestDataCipher_ShortCiphertext(t *testing.T) {
+	dc1 := newDataCipher()
+	shortText := make([]byte, dataHeaderSize+dataCipherOverhead-1)
+	rand.Read(shortText)
+	_, ok := dc1.Decrypt(shortText, make([]byte, bufferSize))
+	if ok {
+		t.Fatal(ok)
+	}
+}
+
+func BenchmarkDataCipher_Encrypt(b *testing.B) {
+	h1 := header{
+		Counter:  235153,
+		SourceIP: 4,
+		DestIP:   88,
+	}
+
+	plaintext := make([]byte, bufferSize-dataHeaderSize-dataCipherOverhead)
+	rand.Read(plaintext)
+
+	encrypted := make([]byte, bufferSize)
+
+	dc1 := newDataCipher()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		encrypted = dc1.Encrypt(h1, plaintext, encrypted)
+	}
+}
+
+func BenchmarkDataCipher_Decrypt(b *testing.B) {
+	h1 := header{
+		Counter:  235153,
+		SourceIP: 4,
+		DestIP:   88,
+	}
+
+	plaintext := make([]byte, bufferSize-dataHeaderSize-dataCipherOverhead)
+	rand.Read(plaintext)
+
+	encrypted := make([]byte, bufferSize)
+
+	dc1 := newDataCipher()
+	encrypted = dc1.Encrypt(h1, plaintext, encrypted)
+
+	decrypted := make([]byte, bufferSize)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		decrypted, _ = dc1.Decrypt(encrypted, decrypted)
+	}
+}