implement cert compression with cached certificates

crypto/cert_compression_test.go

@@ -0,0 +1,98 @@
+package crypto
+
+import (
+	"bytes"
+	"compress/flate"
+	"compress/zlib"
+	"encoding/binary"
+	"hash/fnv"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func byteHash(d []byte) []byte {
+	h := fnv.New64()
+	h.Write(d)
+	s := h.Sum64()
+	res := make([]byte, 8)
+	binary.LittleEndian.PutUint64(res, s)
+	return res
+}
+
+var _ = Describe("Cert compression", func() {
+	It("compresses empty", func() {
+		compressed, err := compressChain(nil, nil, nil)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(compressed).To(Equal([]byte{0}))
+	})
+
+	It("gives correct single cert", func() {
+		cert := []byte{0xde, 0xca, 0xfb, 0xad}
+		certZlib := &bytes.Buffer{}
+		z, err := zlib.NewWriterLevelDict(certZlib, flate.BestCompression, certDictZlib)
+		Expect(err).ToNot(HaveOccurred())
+		z.Write([]byte{0x04, 0x00, 0x00, 0x00})
+		z.Write(cert)
+		z.Close()
+		chain := [][]byte{cert}
+		compressed, err := compressChain(chain, nil, nil)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(compressed).To(Equal(append([]byte{
+			0x01, 0x00,
+			0x08, 0x00, 0x00, 0x00,
+		}, certZlib.Bytes()...)))
+	})
+
+	It("gives correct cert and intermediate", func() {
+		cert1 := []byte{0xde, 0xca, 0xfb, 0xad}
+		cert2 := []byte{0xde, 0xad, 0xbe, 0xef}
+		certZlib := &bytes.Buffer{}
+		z, err := zlib.NewWriterLevelDict(certZlib, flate.BestCompression, certDictZlib)
+		Expect(err).ToNot(HaveOccurred())
+		z.Write([]byte{0x04, 0x00, 0x00, 0x00})
+		z.Write(cert1)
+		z.Write([]byte{0x04, 0x00, 0x00, 0x00})
+		z.Write(cert2)
+		z.Close()
+		chain := [][]byte{cert1, cert2}
+		compressed, err := compressChain(chain, nil, nil)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(compressed).To(Equal(append([]byte{
+			0x01, 0x01, 0x00,
+			0x10, 0x00, 0x00, 0x00,
+		}, certZlib.Bytes()...)))
+	})
+
+	It("uses cached certificates", func() {
+		cert := []byte{0xde, 0xca, 0xfb, 0xad}
+		certHash := byteHash(cert)
+		chain := [][]byte{cert}
+		compressed, err := compressChain(chain, nil, certHash)
+		Expect(err).ToNot(HaveOccurred())
+		expected := append([]byte{0x02}, certHash...)
+		expected = append(expected, 0x00)
+		Expect(compressed).To(Equal(expected))
+	})
+
+	It("uses cached certificates and compressed combined", func() {
+		cert1 := []byte{0xde, 0xca, 0xfb, 0xad}
+		cert2 := []byte{0xde, 0xad, 0xbe, 0xef}
+		cert2Hash := byteHash(cert2)
+		certZlib := &bytes.Buffer{}
+		z, err := zlib.NewWriterLevelDict(certZlib, flate.BestCompression, append(cert2, certDictZlib...))
+		Expect(err).ToNot(HaveOccurred())
+		z.Write([]byte{0x04, 0x00, 0x00, 0x00})
+		z.Write(cert1)
+		z.Close()
+		chain := [][]byte{cert1, cert2}
+		compressed, err := compressChain(chain, nil, cert2Hash)
+		Expect(err).ToNot(HaveOccurred())
+		expected := []byte{0x01, 0x02}
+		expected = append(expected, cert2Hash...)
+		expected = append(expected, 0x00)
+		expected = append(expected, []byte{0x08, 0, 0, 0}...)
+		expected = append(expected, certZlib.Bytes()...)
+		Expect(compressed).To(Equal(expected))
+	})
+})