dhcpv6 fqdn: fix domain encoding

Signed-off-by: Pablo Mazzini <pmazzini@gmail.com>

4 files changed, 25 insertions, 13 deletions

diff --git a/dhcpv6/modifiers.go b/dhcpv6/modifiers.go
index dbf5d82..95f49d1 100644
--- a/dhcpv6/modifiers.go
+++ b/dhcpv6/modifiers.go
@@ -32,8 +32,12 @@ func WithNetboot(d DHCPv6) {
 // WithFQDN adds a fully qualified domain name option to the packet
 func WithFQDN(flags uint8, domainname string) Modifier {
 	return func(d DHCPv6) {
-		ofqdn := OptFQDN{Flags: flags, DomainName: domainname}
-		d.AddOption(&ofqdn)
+		d.UpdateOption(&OptFQDN{
+			Flags:      flags,
+			DomainName: &rfc1035label.Labels{
+				Labels: []string{domainname},
+			},
+		})
 	}
 }
 
diff --git a/dhcpv6/modifiers_test.go b/dhcpv6/modifiers_test.go
index bd328a3..8d06e75 100644
--- a/dhcpv6/modifiers_test.go
+++ b/dhcpv6/modifiers_test.go
@@ -90,7 +90,7 @@ func TestWithFQDN(t *testing.T) {
 	ofqdn := d.Options.FQDN()
 	require.Equal(t, OptionFQDN, ofqdn.Code())
 	require.Equal(t, uint8(4), ofqdn.Flags)
-	require.Equal(t, "cnos.localhost", ofqdn.DomainName)
+	require.Equal(t, "cnos.localhost", ofqdn.DomainName.Labels[0])
 }
 
 func TestWithDHCP4oDHCP6Server(t *testing.T) {
diff --git a/dhcpv6/option_fqdn.go b/dhcpv6/option_fqdn.go
index 82d1254..8bac95d 100644
--- a/dhcpv6/option_fqdn.go
+++ b/dhcpv6/option_fqdn.go
@@ -3,6 +3,7 @@ package dhcpv6
 import (
 	"fmt"
 
+	"github.com/insomniacslk/dhcp/rfc1035label"
 	"github.com/u-root/u-root/pkg/uio"
 )
 
@@ -11,7 +12,7 @@ import (
 // https://tools.ietf.org/html/rfc4704
 type OptFQDN struct {
 	Flags      uint8
-	DomainName string
+	DomainName *rfc1035label.Labels
 }
 
 // Code returns the option code.
@@ -23,7 +24,7 @@ func (op *OptFQDN) Code() OptionCode {
 func (op *OptFQDN) ToBytes() []byte {
 	buf := uio.NewBigEndianBuffer(nil)
 	buf.Write8(op.Flags)
-	buf.WriteBytes([]byte(op.DomainName))
+	buf.WriteBytes(op.DomainName.ToBytes())
 	return buf.Data()
 }
 
@@ -34,8 +35,12 @@ func (op *OptFQDN) String() string {
 // ParseOptFQDN deserializes from bytes to build a OptFQDN structure.
 func ParseOptFQDN(data []byte) (*OptFQDN, error) {
 	var opt OptFQDN
+	var err error
 	buf := uio.NewBigEndianBuffer(data)
 	opt.Flags = buf.Read8()
-	opt.DomainName = string(buf.ReadAll())
+	opt.DomainName, err = rfc1035label.FromBytes(buf.ReadAll())
+	if err != nil {
+		return nil, err
+	}
 	return &opt, buf.FinError()
 }
diff --git a/dhcpv6/option_fqdn_test.go b/dhcpv6/option_fqdn_test.go
index 870ed9d..f698c93 100644
--- a/dhcpv6/option_fqdn_test.go
+++ b/dhcpv6/option_fqdn_test.go
@@ -4,33 +4,36 @@ import (
 	"bytes"
 	"testing"
 
+	"github.com/insomniacslk/dhcp/rfc1035label"
 	"github.com/stretchr/testify/require"
 )
 
 func TestParseOptFQDN(t *testing.T) {
 	data := []byte{
 		0, // Flags
-		'c', 'n', 'o', 's', '.', 'l', 'o', 'c', 'a', 'l',
-		'h', 'o', 's', 't',
+		4, 'c', 'n', 'o', 's', 9, 'l', 'o', 'c', 'a', 'l',
+		'h', 'o', 's', 't', 0,
 	}
 	opt, err := ParseOptFQDN(data)
 
 	require.NoError(t, err)
 	require.Equal(t, OptionFQDN, opt.Code())
 	require.Equal(t, uint8(0), opt.Flags)
-	require.Equal(t, "cnos.localhost", opt.DomainName)
-	require.Equal(t, "OptFQDN{flags=0, domainname=cnos.localhost}", opt.String())
+	require.Equal(t, "cnos.localhost", opt.DomainName.Labels[0])
+	require.Equal(t, "OptFQDN{flags=0, domainname=[cnos.localhost]}", opt.String())
 }
 
 func TestOptFQDNToBytes(t *testing.T) {
 	opt := OptFQDN{
 		Flags:      0,
-		DomainName: "cnos.localhost",
+		DomainName: &rfc1035label.Labels{
+			Labels: []string{"cnos.localhost"},
+		},
 	}
 	want := []byte{
 		0, // Flags
-		'c', 'n', 'o', 's', '.', 'l', 'o', 'c', 'a', 'l',
-		'h', 'o', 's', 't',
+		4, 'c', 'n', 'o', 's', 9, 'l', 'o', 'c', 'a', 'l',
+		'h', 'o', 's', 't', 0,
 	}
 	b := opt.ToBytes()
 	if !bytes.Equal(b, want) {