Add CipherSuites and InsecureCipherSuites

As part of Go 1.14 the CipherSuites and InsecureCipherSuites functions
got added to the TLS package, returning a slice of *tls.CipherSuite.

Relates to #148

cipher_suite.go

@@ -28,6 +28,10 @@ const (
 	TLS_PSK_WITH_AES_128_GCM_SHA256 CipherSuiteID = 0x00a8
 )
 
+var (
+	_ = allCipherSuites() // Necessary until this function isn't only used by Go 1.14
+)
+
 func (c CipherSuiteID) String() string {
 	switch c {
 	case TLS_ECDHE_ECDSA_WITH_AES_128_CCM:
@@ -120,6 +124,20 @@ func defaultCipherSuites() []cipherSuite {
 	}
 }
 
+func allCipherSuites() []cipherSuite {
+	return []cipherSuite{
+		newCipherSuiteTLSEcdheEcdsaWithAes128Ccm(),
+		newCipherSuiteTLSEcdheEcdsaWithAes128Ccm8(),
+		&cipherSuiteTLSEcdheEcdsaWithAes128GcmSha256{},
+		&cipherSuiteTLSEcdheRsaWithAes128GcmSha256{},
+		&cipherSuiteTLSEcdheEcdsaWithAes256CbcSha{},
+		&cipherSuiteTLSEcdheRsaWithAes256CbcSha{},
+		newCipherSuiteTLSPskWithAes128Ccm(),
+		newCipherSuiteTLSPskWithAes128Ccm8(),
+		&cipherSuiteTLSPskWithAes128GcmSha256{},
+	}
+}
+
 func decodeCipherSuites(buf []byte) ([]cipherSuite, error) {
 	if len(buf) < 2 {
 		return nil, errDTLSPacketInvalidLength

cipher_suite_go114.go

@@ -0,0 +1,36 @@
+// +build go1.14
+
+package dtls
+
+import (
+	"crypto/tls"
+)
+
+// Convert from our cipherSuite interface to a tls.CipherSuite struct
+func toTLSCipherSuite(c cipherSuite) *tls.CipherSuite {
+	return &tls.CipherSuite{
+		ID:                uint16(c.ID()),
+		Name:              c.String(),
+		SupportedVersions: []uint16{VersionDTLS12},
+		Insecure:          false,
+	}
+}
+
+// CipherSuites returns a list of cipher suites currently implemented by this
+// package, excluding those with security issues, which are returned by
+// InsecureCipherSuites.
+func CipherSuites() []*tls.CipherSuite {
+	suites := allCipherSuites()
+	res := make([]*tls.CipherSuite, len(suites))
+	for i, c := range suites {
+		res[i] = toTLSCipherSuite(c)
+	}
+	return res
+}
+
+// InsecureCipherSuites returns a list of cipher suites currently implemented by
+// this package and which have security issues.
+func InsecureCipherSuites() []*tls.CipherSuite {
+	var res []*tls.CipherSuite
+	return res
+}

cipher_suite_go114_test.go

@@ -0,0 +1,51 @@
+// +build go1.14
+
+package dtls
+
+import (
+	"testing"
+)
+
+func TestInsecureCipherSuites(t *testing.T) {
+	r := InsecureCipherSuites()
+
+	if len(r) != 0 {
+		t.Fatalf("Expected no insecure ciphersuites, got %d", len(r))
+	}
+}
+
+func TestCipherSuites(t *testing.T) {
+	ours := allCipherSuites()
+	theirs := CipherSuites()
+
+	if len(ours) != len(theirs) {
+		t.Fatalf("Expected %d CipherSuites, got %d", len(ours), len(theirs))
+	}
+
+	for i, s := range ours {
+		i := i
+		s := s
+		t.Run(s.String(), func(t *testing.T) {
+			c := theirs[i]
+			if c.ID != uint16(s.ID()) {
+				t.Fatalf("Expected ID: 0x%04X, got 0x%04X", s.ID(), c.ID)
+			}
+
+			if c.Name != s.String() {
+				t.Fatalf("Expected Name: %s, got %s", s.String(), c.Name)
+			}
+
+			if len(c.SupportedVersions) != 1 {
+				t.Fatalf("Expected %d SupportedVersion, got %d", 1, len(c.SupportedVersions))
+			}
+
+			if c.SupportedVersions[0] != VersionDTLS12 {
+				t.Fatalf("Expected SupportedVersions 0x%04X, got 0x%04X", VersionDTLS12, c.SupportedVersions[0])
+			}
+
+			if c.Insecure {
+				t.Fatalf("Expected Insecure %t, got %t", false, c.Insecure)
+			}
+		})
+	}
+}

cipher_suite_test.go

@@ -38,3 +38,10 @@ func TestCipherSuiteName(t *testing.T) {
 		}
 	}
 }
+
+func TestAllCipherSuites(t *testing.T) {
+	actual := len(allCipherSuites())
+	if actual == 0 {
+		t.Fatal()
+	}
+}

record_layer_header.go

@@ -17,6 +17,10 @@ const (
 
 	dtls1_2Major = 0xfe
 	dtls1_2Minor = 0xfd
+
+	// VersionDTLS12 is the DTLS version in the same style as
+	// VersionTLSXX from crypto/tls
+	VersionDTLS12 = 0xfefd
 )
 
 var protocolVersion1_2 = protocolVersion{dtls1_2Major, dtls1_2Minor}