Add support for Bootfile name option (#91)

2 files changed, 114 insertions, 0 deletions

diff --git a/dhcpv4/option_bootfile_name.go b/dhcpv4/option_bootfile_name.go
new file mode 100644
index 0000000..73ea625
--- /dev/null
+++ b/dhcpv4/option_bootfile_name.go
@@ -0,0 +1,54 @@
+package dhcpv4
+
+import (
+	"fmt"
+)
+
+// This option implements the Bootfile name Option.
+// https://tools.ietf.org/html/rfc2132
+
+// OptBootfileName implements the BootFile Name option
+type OptBootfileName struct {
+	BootfileName []byte
+}
+
+// Code returns the option code
+func (op *OptBootfileName) Code() OptionCode {
+	return OptionBootfileName
+}
+
+// ToBytes serializes the option and returns it as a sequence of bytes
+func (op *OptBootfileName) ToBytes() []byte {
+	return append([]byte{byte(op.Code()), byte(op.Length())}, op.BootfileName...)
+}
+
+// Length returns the option length in bytes
+func (op *OptBootfileName) Length() int {
+	return len(op.BootfileName)
+}
+
+func (op *OptBootfileName) String() string {
+	return fmt.Sprintf("OptBootfileName{BootfileName=%s}", op.BootfileName)
+
+}
+
+// ParseOptBootfileName returns a new OptBootfile from a byte stream or error if any
+func ParseOptBootfileName(data []byte) (*OptBootfileName, error) {
+	if len(data) < 3 {
+		return nil, ErrShortByteStream
+	}
+	code := OptionCode(data[0])
+	if code != OptionBootfileName {
+		return nil, fmt.Errorf("ParseOptBootfileName: invalid code: %v; want %v", code, OptionBootfileName)
+	}
+	length := int(data[1])
+	if length < 1 {
+		return nil, fmt.Errorf("Bootfile name has invalid length of %d", length)
+	}
+	bootFileNameData := data[2:]
+	if len(bootFileNameData) < length {
+		return nil, fmt.Errorf("ParseOptBootfileName: short data: %d bytes; want %d",
+			len(bootFileNameData), length)
+	}
+	return &OptBootfileName{BootfileName: bootFileNameData[:length]}, nil
+}
diff --git a/dhcpv4/option_bootfile_name_test.go b/dhcpv4/option_bootfile_name_test.go
new file mode 100644
index 0000000..1f66807
--- /dev/null
+++ b/dhcpv4/option_bootfile_name_test.go
@@ -0,0 +1,60 @@
+package dhcpv4
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestOptBootfileNameCode(t *testing.T) {
+	opt := OptBootfileName{}
+	require.Equal(t, OptionBootfileName, opt.Code())
+}
+
+func TestOptBootfileNameToBytes(t *testing.T) {
+	opt := OptBootfileName{
+		BootfileName: []byte("linuxboot"),
+	}
+	data := opt.ToBytes()
+	expected := []byte{
+		67, // OptionBootfileName
+		9,  // length
+		'l', 'i', 'n', 'u', 'x', 'b', 'o', 'o', 't',
+	}
+	require.Equal(t, expected, data)
+}
+
+func TestParseOptBootfileName(t *testing.T) {
+	expected := []byte{
+		67, 9, 'l', 'i', 'n', 'u', 'x', 'b', 'o', 'o', 't',
+	}
+	opt, err := ParseOptBootfileName(expected)
+	require.NoError(t, err)
+	require.Equal(t, 9, opt.Length())
+	require.Equal(t, "linuxboot", string(opt.BootfileName))
+}
+
+func TestParseOptBootfileNameZeroLength(t *testing.T) {
+	expected := []byte{
+		67, 0,
+	}
+	_, err := ParseOptBootfileName(expected)
+	require.Error(t, err)
+}
+
+func TestParseOptBootfileNameInvalidLength(t *testing.T) {
+	expected := []byte{
+		67, 9, 'l', 'i', 'n', 'u', 'x', 'b',
+	}
+	_, err := ParseOptBootfileName(expected)
+	require.Error(t, err)
+}
+
+func TestParseOptBootfileNameShortLength(t *testing.T) {
+	expected := []byte{
+		67, 4, 'l', 'i', 'n', 'u', 'x',
+	}
+	opt, err := ParseOptBootfileName(expected)
+	require.NoError(t, err)
+	require.Equal(t, []byte("linu"), opt.BootfileName)
+}