diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/debian/changelog golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/debian/changelog
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/debian/changelog	2020-06-19 08:12:44.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/debian/changelog	2020-07-10 14:33:16.000000000 +0000
@@ -1,3 +1,9 @@
+golang-github-insomniacslk-dhcp (0.0~git20200621.d74cd86-1) unstable; urgency=medium
+
+  * New upstream snapshot
+
+ -- Shengjing Zhu <zhsj@debian.org>  Fri, 10 Jul 2020 22:33:16 +0800
+
 golang-github-insomniacslk-dhcp (0.0~git20200420.ed3125c-1) unstable; urgency=medium
 
   * Initial release (Closes: #963113)
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/dhcpv4.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/dhcpv4.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/dhcpv4.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/dhcpv4.go	2020-07-10 14:30:30.000000000 +0000
@@ -144,6 +144,7 @@
 	d := DHCPv4{
 		OpCode:        OpcodeBootRequest,
 		HWType:        iana.HWTypeEthernet,
+		ClientHWAddr:  make(net.HardwareAddr, 6),
 		HopCount:      0,
 		TransactionID: xid,
 		NumSeconds:    0,
@@ -476,9 +477,6 @@
 
 	// HwAddrLen
 	hlen := uint8(len(d.ClientHWAddr))
-	if hlen == 0 && d.HWType == iana.HWTypeEthernet {
-		hlen = 6
-	}
 	buf.Write8(hlen)
 	buf.Write8(d.HopCount)
 	buf.WriteBytes(d.TransactionID[:])
@@ -492,13 +490,11 @@
 	copy(buf.WriteN(16), d.ClientHWAddr)
 
 	var sname [64]byte
-	copy(sname[:], []byte(d.ServerHostName))
-	sname[len(d.ServerHostName)] = 0
+	copy(sname[:63], []byte(d.ServerHostName))
 	buf.WriteBytes(sname[:])
 
 	var file [128]byte
-	copy(file[:], []byte(d.BootFileName))
-	file[len(d.BootFileName)] = 0
+	copy(file[:127], []byte(d.BootFileName))
 	buf.WriteBytes(file[:])
 
 	// The magic cookie.
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/dhcpv4_test.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/dhcpv4_test.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/dhcpv4_test.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/dhcpv4_test.go	2020-07-10 14:30:30.000000000 +0000
@@ -3,6 +3,8 @@
 import (
 	"bytes"
 	"net"
+	"strconv"
+	"strings"
 	"testing"
 
 	"github.com/insomniacslk/dhcp/iana"
@@ -80,16 +82,18 @@
 	// above
 }
 
-func TestFromBytesZeroLength(t *testing.T) {
-	data := []byte{}
-	_, err := FromBytes(data)
-	require.Error(t, err)
-}
-
-func TestFromBytesShortLength(t *testing.T) {
-	data := []byte{1, 1, 6, 0}
-	_, err := FromBytes(data)
-	require.Error(t, err)
+func TestFromBytesGenericInvalid(t *testing.T) {
+	data := [][]byte{
+		{},
+		{1, 1, 6, 0},
+	}
+	t.Parallel()
+	for i, packet := range data {
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
+			_, err := FromBytes(packet)
+			require.Error(t, err)
+		})
+	}
 }
 
 func TestFromBytesInvalidOptions(t *testing.T) {
@@ -178,6 +182,17 @@
 	require.Equal(t, expected, got)
 }
 
+func TestToBytesStringTooLong(t *testing.T) {
+	d, err := New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	d.ServerHostName = strings.Repeat("a", 256)
+	d.BootFileName = strings.Repeat("a", 256)
+
+	require.NotPanics(t, func() { _ = d.ToBytes() })
+}
+
 func TestGetOption(t *testing.T) {
 	d, err := New()
 	if err != nil {
@@ -339,7 +354,7 @@
 		"  your IP: 0.0.0.0\n" +
 		"  server IP: 0.0.0.0\n" +
 		"  gateway IP: 0.0.0.0\n" +
-		"  client MAC: \n" +
+		"  client MAC: 00:00:00:00:00:00\n" +
 		"  server hostname: \n" +
 		"  bootfile name: \n" +
 		"  options:\n" +
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/fuzz.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/fuzz.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/fuzz.go	1970-01-01 00:00:00.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/fuzz.go	2020-07-10 14:30:30.000000000 +0000
@@ -0,0 +1,41 @@
+// +build gofuzz
+
+package dhcpv4
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// Fuzz is the entrypoint for go-fuzz
+func Fuzz(data []byte) int {
+	msg, err := FromBytes(data)
+	if err != nil {
+		return 0
+	}
+
+	serialized := msg.ToBytes()
+
+	// Compared to dhcpv6, dhcpv4 has padding and fixed-size fields containing
+	// variable-length data; We can't expect the library to output byte-for-byte
+	// identical packets after a round-trip.
+	// Instead, we check that after a round-trip, the packet reserializes to the
+	// same internal representation
+	rtMsg, err := FromBytes(serialized)
+
+	if err != nil || !reflect.DeepEqual(msg, rtMsg) {
+		fmt.Printf("Input:      %x\n", data)
+		fmt.Printf("Round-trip: %x\n", serialized)
+		fmt.Println("Message: ", msg.Summary())
+		fmt.Printf("Go repr: %#v\n", msg)
+		fmt.Println("Reserialized: ", rtMsg.Summary())
+		fmt.Printf("Go repr: %#v\n", rtMsg)
+		if err != nil {
+			fmt.Printf("Got error while reserializing: %v\n", err)
+			panic("round-trip error: " + err.Error())
+		}
+		panic("round-trip different: " + msg.Summary())
+	}
+
+	return 1
+}
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/option_routes.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/option_routes.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/option_routes.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/option_routes.go	2020-07-10 14:30:30.000000000 +0000
@@ -38,6 +38,9 @@
 // Unmarshal implements uio.Unmarshaler.
 func (r *Route) Unmarshal(buf *uio.Lexer) error {
 	maskSize := buf.Read8()
+	if maskSize > 32 {
+		return fmt.Errorf("invalid mask length %d in route option", maskSize)
+	}
 	r.Dest = &net.IPNet{
 		IP:   make([]byte, net.IPv4len),
 		Mask: net.CIDRMask(int(maskSize), 32),
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/option_routes_test.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/option_routes_test.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/option_routes_test.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/option_routes_test.go	2020-07-10 14:30:30.000000000 +0000
@@ -16,9 +16,9 @@
 
 func TestParseRoutes(t *testing.T) {
 	for _, tt := range []struct {
-		p    []byte
-		want Routes
-		err  error
+		p       []byte
+		want    Routes
+		wantErr bool
 	}{
 		{
 			p: []byte{32, 10, 2, 3, 4, 0, 0, 0, 0},
@@ -51,10 +51,14 @@
 				},
 			},
 		},
+		{
+			p:       []byte{64, 10, 2, 3, 4},
+			wantErr: true, // Mask length 64 > 32
+		},
 	} {
 		var r Routes
-		if err := r.FromBytes(tt.p); err != tt.err {
-			t.Errorf("FromBytes(%v) = %v, want %v", tt.p, err, tt.err)
+		if err := r.FromBytes(tt.p); (err != nil) != tt.wantErr {
+			t.Errorf("FromBytes(%v) Unexpected error state: %v", tt.p, err)
 		}
 
 		if !reflect.DeepEqual(r, tt.want) {
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/options.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/options.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/options.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/options.go	2020-07-10 14:30:30.000000000 +0000
@@ -185,12 +185,20 @@
 		code := uint8(c)
 		// Even if the End option is in there, don't marshal it until
 		// the end.
-		if code == optEnd {
+		// Don't write padding either, since the options are sorted
+		// it would always be written first which isn't useful
+		if code == optEnd || code == optPad {
 			continue
 		}
 
 		data := o[code]
 
+		// Ensure even 0-length options are written out
+		if len(data) == 0 {
+			b.Write8(code)
+			b.Write8(0)
+			continue
+		}
 		// RFC 3396: If more than 256 bytes of data are given, the
 		// option is simply listed multiple times.
 		for len(data) > 0 {
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/options_test.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/options_test.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv4/options_test.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv4/options_test.go	2020-07-10 14:30:30.000000000 +0000
@@ -194,9 +194,25 @@
 				5, 1, 10,
 			),
 		},
+		{
+			// Test 0-length options
+			opts: Options{
+				80: []byte{},
+			},
+			want: []byte{80, 0},
+		},
+		{
+			// Test special options, handled by the message marshalling code
+			// and ignored by the options marshalling code
+			opts: Options{
+				0:   []byte{}, // Padding
+				255: []byte{}, // End of options
+			},
+			want: nil, // not written out
+		},
 	} {
 		t.Run(fmt.Sprintf("Test %02d", i), func(t *testing.T) {
-			require.Equal(t, uio.ToBigEndian(tt.opts), tt.want)
+			require.Equal(t, tt.want, uio.ToBigEndian(tt.opts))
 		})
 	}
 }
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/dhcpv6relay.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/dhcpv6relay.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/dhcpv6relay.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/dhcpv6relay.go	2020-07-10 14:30:30.000000000 +0000
@@ -5,6 +5,7 @@
 	"fmt"
 	"net"
 
+	"github.com/insomniacslk/dhcp/iana"
 	"github.com/u-root/u-root/pkg/uio"
 )
 
@@ -54,6 +55,19 @@
 	return nil
 }
 
+// ClientLinkLayerAddress returns the Hardware Type and
+// Link Layer Address of the requesting client in this relay message.
+func (ro RelayOptions) ClientLinkLayerAddress() (iana.HWType, net.HardwareAddr) {
+	opt := ro.Options.GetOne(OptionClientLinkLayerAddr)
+	if opt == nil {
+		return 0, nil
+	}
+	if lla, ok := opt.(*optClientLinkLayerAddress); ok {
+		return lla.LinkLayerType, lla.LinkLayerAddress
+	}
+	return 0, nil
+}
+
 // RelayMessage is a DHCPv6 relay agent message as defined by RFC 3315 Section
 // 7.
 type RelayMessage struct {
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/modifiers.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/modifiers.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/modifiers.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/modifiers.go	2020-07-10 14:30:30.000000000 +0000
@@ -152,3 +152,9 @@
 		}
 	}
 }
+
+// WithClientLinkLayerAddress adds or updates the ClientLinkLayerAddress
+// option with provided HWType and HWAddress on a DHCPv6 packet
+func WithClientLinkLayerAddress(ht iana.HWType, lla net.HardwareAddr) Modifier {
+	return WithOption(OptClientLinkLayerAddress(ht, lla))
+}
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/modifiers_test.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/modifiers_test.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/modifiers_test.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/modifiers_test.go	2020-07-10 14:30:30.000000000 +0000
@@ -121,3 +121,16 @@
 	require.Equal(t, 1, len(opt))
 	require.Equal(t, OptionIAPD, opt[0].Code())
 }
+
+func TestWithClientLinkLayerAddress(t *testing.T) {
+	var d RelayMessage
+	mac, _ := net.ParseMAC("a4:83:e7:e3:df:88")
+	WithClientLinkLayerAddress(iana.HWTypeEthernet, mac)(&d)
+
+	opt := d.Options.GetOne(OptionClientLinkLayerAddr)
+	require.Equal(t, OptionClientLinkLayerAddr, opt.Code())
+
+	llt, lla := d.Options.ClientLinkLayerAddress()
+	require.Equal(t, iana.HWTypeEthernet, llt)
+	require.Equal(t, mac, lla)
+}
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/option_clientlinklayeraddress.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/option_clientlinklayeraddress.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/option_clientlinklayeraddress.go	1970-01-01 00:00:00.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/option_clientlinklayeraddress.go	2020-07-10 14:30:30.000000000 +0000
@@ -0,0 +1,47 @@
+package dhcpv6
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/insomniacslk/dhcp/iana"
+	"github.com/u-root/u-root/pkg/uio"
+)
+
+// OptClientLinkLayerAddress implements OptionClientLinkLayerAddr option.
+// https://tools.ietf.org/html/rfc6939
+func OptClientLinkLayerAddress(ht iana.HWType, lla net.HardwareAddr) *optClientLinkLayerAddress {
+	return &optClientLinkLayerAddress{LinkLayerType: ht, LinkLayerAddress: lla}
+}
+
+type optClientLinkLayerAddress struct {
+	LinkLayerType    iana.HWType
+	LinkLayerAddress net.HardwareAddr
+}
+
+// Code returns the option code.
+func (op *optClientLinkLayerAddress) Code() OptionCode {
+	return OptionClientLinkLayerAddr
+}
+
+// ToBytes serializes the option and returns it as a sequence of bytes
+func (op *optClientLinkLayerAddress) ToBytes() []byte {
+	buf := uio.NewBigEndianBuffer(nil)
+	buf.Write16(uint16(op.LinkLayerType))
+	buf.WriteBytes(op.LinkLayerAddress)
+	return buf.Data()
+}
+
+func (op *optClientLinkLayerAddress) String() string {
+	return fmt.Sprintf("ClientLinkLayerAddress: Type=%s LinkLayerAddress=%s", op.LinkLayerType, op.LinkLayerAddress)
+}
+
+// parseOptClientLinkLayerAddress deserializes from bytes
+// to build an optClientLinkLayerAddress structure.
+func parseOptClientLinkLayerAddress(data []byte) (*optClientLinkLayerAddress, error) {
+	var opt optClientLinkLayerAddress
+	buf := uio.NewBigEndianBuffer(data)
+	opt.LinkLayerType = iana.HWType(buf.Read16())
+	opt.LinkLayerAddress = buf.ReadAll()
+	return &opt, buf.FinError()
+}
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/option_clientlinklayeraddress_test.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/option_clientlinklayeraddress_test.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/option_clientlinklayeraddress_test.go	1970-01-01 00:00:00.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/option_clientlinklayeraddress_test.go	2020-07-10 14:30:30.000000000 +0000
@@ -0,0 +1,40 @@
+package dhcpv6
+
+import (
+	"bytes"
+	"net"
+	"testing"
+
+	"github.com/insomniacslk/dhcp/iana"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseOptClientLinkLayerAddress(t *testing.T) {
+	data := []byte{
+		0, 1, // LinkLayerType
+		164, 131, 231, 227, 223, 136,
+	}
+	opt, err := parseOptClientLinkLayerAddress(data)
+
+	require.NoError(t, err)
+	require.Equal(t, OptionClientLinkLayerAddr, opt.Code())
+	require.Equal(t, iana.HWTypeEthernet, opt.LinkLayerType)
+	require.Equal(t, net.HardwareAddr(data[2:]), opt.LinkLayerAddress)
+	require.Equal(t, "ClientLinkLayerAddress: Type=Ethernet LinkLayerAddress=a4:83:e7:e3:df:88", opt.String())
+}
+
+func TestOptClientLinkLayerAddressToBytes(t *testing.T) {
+	mac, _ := net.ParseMAC("a4:83:e7:e3:df:88")
+	opt := optClientLinkLayerAddress{
+		LinkLayerType:    iana.HWTypeEthernet,
+		LinkLayerAddress: mac,
+	}
+	want := []byte{
+		0, 1, // LinkLayerType
+		164, 131, 231, 227, 223, 136,
+	}
+	b := opt.ToBytes()
+	if !bytes.Equal(b, want) {
+		t.Fatalf("opt.ToBytes()=%v, want %v", b, want)
+	}
+}
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/options.go golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/options.go
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/dhcpv6/options.go	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/dhcpv6/options.go	2020-07-10 14:30:30.000000000 +0000
@@ -87,6 +87,8 @@
 		var o OptNetworkInterfaceID
 		err = o.FromBytes(optData)
 		opt = &o
+	case OptionClientLinkLayerAddr:
+		opt, err = parseOptClientLinkLayerAddress(optData)
 	case OptionDHCPv4Msg:
 		opt, err = ParseOptDHCPv4Msg(optData)
 	case OptionDHCP4oDHCP6Server:
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/.travis/linters.sh golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/.travis/linters.sh
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/.travis/linters.sh	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/.travis/linters.sh	2020-07-10 14:30:30.000000000 +0000
@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 
-go get github.com/golangci/golangci-lint/cmd/golangci-lint
-go install github.com/golangci/golangci-lint/cmd/golangci-lint
-golangci-lint run
+set -e
+
+GO111MODULE=on go get github.com/golangci/golangci-lint/cmd/golangci-lint
+$GOPATH/bin/golangci-lint run
diff -Nru golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/.travis.yml golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/.travis.yml
--- golang-github-insomniacslk-dhcp-0.0~git20200420.ed3125c/.travis.yml	2020-04-30 19:24:52.000000000 +0000
+++ golang-github-insomniacslk-dhcp-0.0~git20200621.d74cd86/.travis.yml	2020-07-10 14:30:30.000000000 +0000
@@ -3,9 +3,8 @@
 sudo: required
 
 go:
-  - "1.11"
-  - "1.12"
   - "1.13"
+  - "1.14"
 
 env:
   - TEST_SUITE=unit