hcpv6 fqdn: implements OptionFQDN option

per https://tools.ietf.org/rfc/rfc4704.txt

Signed-off-by: Xuehao (David) Hu <xuehaohu@google.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/dhcpv6/option_fqdn.go b/dhcpv6/option_fqdn.go
new file mode 100644
index 0000000..82d1254
--- /dev/null
+++ b/dhcpv6/option_fqdn.go
@@ -0,0 +1,41 @@
+package dhcpv6
+
+import (
+	"fmt"
+
+	"github.com/u-root/u-root/pkg/uio"
+)
+
+// OptFQDN implements OptionFQDN option.
+//
+// https://tools.ietf.org/html/rfc4704
+type OptFQDN struct {
+	Flags      uint8
+	DomainName string
+}
+
+// Code returns the option code.
+func (op *OptFQDN) Code() OptionCode {
+	return OptionFQDN
+}
+
+// ToBytes serializes the option and returns it as a sequence of bytes
+func (op *OptFQDN) ToBytes() []byte {
+	buf := uio.NewBigEndianBuffer(nil)
+	buf.Write8(op.Flags)
+	buf.WriteBytes([]byte(op.DomainName))
+	return buf.Data()
+}
+
+func (op *OptFQDN) String() string {
+	return fmt.Sprintf("OptFQDN{flags=%d, domainname=%s}", op.Flags, op.DomainName)
+}
+
+// ParseOptFQDN deserializes from bytes to build a OptFQDN structure.
+func ParseOptFQDN(data []byte) (*OptFQDN, error) {
+	var opt OptFQDN
+	buf := uio.NewBigEndianBuffer(data)
+	opt.Flags = buf.Read8()
+	opt.DomainName = string(buf.ReadAll())
+	return &opt, buf.FinError()
+}