added text marshaler for role

2 files changed, 112 insertions, 13 deletions

diff --git a/satp/crypto-kd.go b/satp/crypto-kd.go
index db52f77..73d2faa 100644
--- a/satp/crypto-kd.go
+++ b/satp/crypto-kd.go
@@ -30,6 +30,11 @@
 
 package satp
 
+import (
+	"errors"
+	"strings"
+)
+
 type KDRole int
 type KeyUsage int
 type Label uint32
@@ -38,11 +43,6 @@ const (
 	RoleLeft KDRole = iota
 	RoleRight
 
-	RoleServer = RoleLeft
-	RoleClient = RoleRight
-	RoleAlice  = RoleLeft
-	RoleBob    = RoleRight
-
 	UsageEncryptKey KeyUsage = iota
 	UsageEncryptSalt
 	UsageAuthKey
@@ -55,6 +55,45 @@ const (
 	LabelRightAuthKey     = 0xC1DFD96E
 )
 
+func (r KDRole) String() string {
+	switch r {
+	case RoleLeft:
+		return "left"
+	case RoleRight:
+		return "right"
+	}
+	return "unknown"
+}
+
+func (r *KDRole) FromString(str string) (err error) {
+	switch strings.ToLower(str) {
+	case "server":
+		fallthrough
+	case "alice":
+		fallthrough
+	case "left":
+		*r = RoleLeft
+	case "client":
+		fallthrough
+	case "bob":
+		fallthrough
+	case "right":
+		*r = RoleRight
+	default:
+		return errors.New("invalid role: '" + str + "'")
+	}
+	return
+}
+
+func (r KDRole) MarshalText() (data []byte, err error) {
+	data = []byte(r.String())
+	return
+}
+
+func (r *KDRole) UnmarshalText(data []byte) (err error) {
+	return r.FromString(string(data))
+}
+
 type KeyDerivation interface {
 	Generate(dir Direction, usage KeyUsage, sequenceNumber uint32, out []byte) error
 }
diff --git a/satp/crypto-kd_test.go b/satp/crypto-kd_test.go
index 1c01fc9..d0db750 100644
--- a/satp/crypto-kd_test.go
+++ b/satp/crypto-kd_test.go
@@ -31,9 +31,69 @@
 package satp
 
 import (
+	"bytes"
 	"testing"
 )
 
+func TestKDRoleMarshalText(t *testing.T) {
+	testvectors := []struct {
+		role KDRole
+		out  []byte
+	}{
+		{RoleLeft, []byte("left")},
+		{RoleRight, []byte("right")},
+		{17, []byte("unknown")},
+	}
+
+	for _, vector := range testvectors {
+		out, err := vector.role.MarshalText()
+		if err != nil {
+			t.Fatal("unexpected error:", err)
+		}
+		if !bytes.Equal(out, vector.out) {
+			t.Fatalf("role name should be %q but is %q", string(vector.out), string(out))
+		}
+	}
+}
+
+func TestKDRoleUnmarshalText(t *testing.T) {
+	testvectors := []struct {
+		role  KDRole
+		in    []byte
+		valid bool
+	}{
+		{RoleLeft, []byte(""), false},
+		{RoleRight, []byte("foo"), false},
+		{RoleLeft, []byte("left-ish"), false},
+		{RoleLeft, []byte("servers"), false},
+		{RoleRight, []byte("eve"), false},
+
+		{RoleLeft, []byte("left"), true},
+		{RoleRight, []byte("right"), true},
+		{RoleLeft, []byte("server"), true},
+		{RoleRight, []byte("client"), true},
+		{RoleLeft, []byte("alice"), true},
+		{RoleRight, []byte("bob"), true},
+	}
+
+	for _, vector := range testvectors {
+		var r KDRole
+		err := r.UnmarshalText(vector.in)
+		if vector.valid {
+			if err != nil {
+				t.Fatal("unexpected error:", err)
+			}
+			if r != vector.role {
+				t.Fatalf("unmarshalling %q returned %s but should be %s", string(vector.in), r, vector.role)
+			}
+		} else {
+			if err == nil {
+				t.Fatalf("unmarshalling %q should give and error", string(vector.in))
+			}
+		}
+	}
+}
+
 func TestKDGetLabel(t *testing.T) {
 	testvectors := []struct {
 		role  KDRole
@@ -43,15 +103,15 @@ func TestKDGetLabel(t *testing.T) {
 	}{
 		{RoleLeft, Outbound, UsageEncryptKey, 0x356A192B},
 		{RoleRight, Outbound, UsageEncryptKey, 0xDA4B9237},
-		{RoleAlice, Outbound, UsageEncryptSalt, 0x77DE68DA},
-		{RoleBob, Outbound, UsageEncryptSalt, 0x1B645389},
-		{RoleServer, Outbound, UsageAuthKey, 0xAC3478D6},
-		{RoleClient, Outbound, UsageAuthKey, 0xC1DFD96E},
+		{RoleLeft, Outbound, UsageEncryptSalt, 0x77DE68DA},
+		{RoleRight, Outbound, UsageEncryptSalt, 0x1B645389},
+		{RoleLeft, Outbound, UsageAuthKey, 0xAC3478D6},
+		{RoleRight, Outbound, UsageAuthKey, 0xC1DFD96E},
 
-		{RoleAlice, Inbound, UsageEncryptKey, 0xDA4B9237},
-		{RoleBob, Inbound, UsageEncryptKey, 0x356A192B},
-		{RoleServer, Inbound, UsageEncryptSalt, 0x1B645389},
-		{RoleClient, Inbound, UsageEncryptSalt, 0x77DE68DA},
+		{RoleLeft, Inbound, UsageEncryptKey, 0xDA4B9237},
+		{RoleRight, Inbound, UsageEncryptKey, 0x356A192B},
+		{RoleLeft, Inbound, UsageEncryptSalt, 0x1B645389},
+		{RoleRight, Inbound, UsageEncryptSalt, 0x77DE68DA},
 		{RoleLeft, Inbound, UsageAuthKey, 0xC1DFD96E},
 		{RoleRight, Inbound, UsageAuthKey, 0xAC3478D6},
 	}