DHCPv4 options as list

dhcpv4/dhcpv4_test.go

@@ -221,7 +221,7 @@ func TestUpdateOption(t *testing.T) {
 	d.UpdateOption(bootFileOpt2)
 
 	options := d.Options
-	require.Equal(t, len(options), 2)
+	require.Equal(t, len(options.opts), 2)
 	require.Equal(t, d.GetOneOption(OptionHostName), []byte("darkstar"))
 	require.Equal(t, d.GetOneOption(OptionBootfileName), []byte("boot2.img"))
 }

dhcpv4/dhcpv4packet.go

@@ -161,7 +161,7 @@ func newDHCPv4(xid TransactionID, modifiers ...Modifier) *DHCPv4 {
 		YourIPAddr:    net.IPv4zero,
 		ServerIPAddr:  net.IPv4zero,
 		GatewayIPAddr: net.IPv4zero,
-		Options:       make(Options),
+		Options:       Options{},
 	}
 	for _, mod := range modifiers {
 		mod(&d)
@@ -322,7 +322,7 @@ func FromBytes(q []byte) (*DHCPv4, error) {
 		return nil, fmt.Errorf("malformed DHCP packet: got magic cookie %v, want %v", cookie[:], magicCookie[:])
 	}
 
-	p.Options = make(Options)
+	p.Options = Options{}
 	if err := p.Options.fromBytesCheckEnd(buf.Data(), true); err != nil {
 		return nil, err
 	}
@@ -373,17 +373,12 @@ func (d *DHCPv4) GetOneOption(code OptionCode) []byte {
 
 // DeleteOption deletes an existing option with the given option code.
 func (d *DHCPv4) DeleteOption(code OptionCode) {
-	if d.Options != nil {
-		d.Options.Del(code)
-	}
+	d.Options.Del(code)
 }
 
 // UpdateOption replaces an existing option with the same option code with the
 // given one, adding it if not already present.
 func (d *DHCPv4) UpdateOption(opt Option) {
-	if d.Options == nil {
-		d.Options = make(Options)
-	}
 	d.Options.Update(opt)
 }
 

dhcpv4/modifiers_test.go

@@ -194,7 +194,7 @@ func TestWithRelayAgentInfo(t *testing.T) {
 
 	opt := resp.RelayAgentInfo()
 	require.NotNil(t, opt)
-	require.Equal(t, len(opt.Options), 2)
+	require.Equal(t, len(opt.Options.opts), 2)
 
 	circuit := opt.Get(GenericOptionCode(1))
 	remote := opt.Get(GenericOptionCode(2))

dhcpv4/nclient4/lease_test.go

@@ -139,7 +139,7 @@ func (sll *testServerLeaseList) testLeaseReleaseHandle(conn net.PacketConn, peer
 		return fmt.Errorf("gateway IP is %v, expect 0", m.GatewayIPAddr)
 	}
 	mustlist, maylist := sll.getCheckList()
-	for o := range m.Options {
+	for o := range m.Options.All() {
 		foundInMust := false
 		foundInMay := false
 		if _, ok := mustlist[o]; ok {

dhcpv4/option_ip_test.go

@@ -17,19 +17,19 @@ func TestOptBroadcastAddress(t *testing.T) {
 }
 
 func TestGetIPs(t *testing.T) {
-	o := Options{102: []byte{}}
+	o := Options{[]optionCodeValue{{102, []byte{}}}}
 	i := GetIPs(optionCode(102), o)
 	require.Nil(t, i)
 
-	o = Options{102: []byte{192, 168, 0}}
+	o = Options{[]optionCodeValue{{102, []byte{192, 168, 0}}}}
 	i = GetIPs(optionCode(102), o)
 	require.Nil(t, i)
 
-	o = Options{102: []byte{192, 168, 0, 1}}
+	o = Options{[]optionCodeValue{{102, []byte{192, 168, 0, 1}}}}
 	i = GetIPs(optionCode(102), o)
 	require.Equal(t, i, []net.IP{{192, 168, 0, 1}})
 
-	o = Options{102: []byte{192, 168, 0, 1, 192, 168, 0, 2}}
+	o = Options{[]optionCodeValue{{102, []byte{192, 168, 0, 1, 192, 168, 0, 2}}}}
 	i = GetIPs(optionCode(102), o)
 	require.Equal(t, i, []net.IP{{192, 168, 0, 1}, {192, 168, 0, 2}})
 }

dhcpv4/option_misc.go

@@ -21,3 +21,8 @@ func OptClientArch(archs ...iana.Arch) Option {
 func OptClientIdentifier(ident []byte) Option {
 	return OptGeneric(OptionClientIdentifier, ident)
 }
+
+// OptPadding returns a new padding option.
+func OptPadding() Option {
+	return OptGeneric(OptionPad, nil)
+}

dhcpv4/option_relay_agent_information.go

@@ -34,7 +34,7 @@ func (r RelayOptions) String() string {
 
 // FromBytes parses relay agent options from data.
 func (r *RelayOptions) FromBytes(data []byte) error {
-	r.Options = make(Options)
+	r.Options = Options{}
 	return r.Options.FromBytes(data)
 }
 

dhcpv4/option_relay_agent_information_test.go

@@ -14,7 +14,7 @@ func TestGetRelayAgentInformation(t *testing.T) {
 
 	opt := m.RelayAgentInfo()
 	require.NotNil(t, opt)
-	require.Equal(t, len(opt.Options), 2)
+	require.Equal(t, len(opt.Options.opts), 2)
 
 	circuit := opt.Get(GenericOptionCode(1))
 	remote := opt.Get(GenericOptionCode(2))

dhcpv4/options.go

@@ -4,8 +4,8 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"iter"
 	"math"
-	"sort"
 	"strings"
 
 	"github.com/insomniacslk/dhcp/iana"
@@ -47,18 +47,35 @@ func (o Option) String() string {
 	return fmt.Sprintf("%s: %s", o.Code, v)
 }
 
+type optionCodeValue struct {
+	code  uint8
+	value []byte
+}
+
 // Options is a collection of options.
-type Options map[uint8][]byte
+type Options struct {
+	opts []optionCodeValue
+}
 
 // OptionsFromList adds all given options to an options map.
 func OptionsFromList(o ...Option) Options {
-	opts := make(Options)
+	opts := Options{}
 	for _, opt := range o {
 		opts.Update(opt)
 	}
 	return opts
 }
 
+func (o Options) All() iter.Seq[uint8] {
+	return func(yield func(uint8) bool) {
+		for _, opt := range o.opts {
+			if !yield(opt.code) {
+				return
+			}
+		}
+	}
+}
+
 // Get will attempt to get all options that match a DHCPv4 option
 // from its OptionCode.  If the option was not found it will return an
 // empty list.
@@ -67,24 +84,47 @@ func OptionsFromList(o ...Option) Options {
 // concatenated, and hence this should always just return one option. This
 // currently returns a list to be API compatible.
 func (o Options) Get(code OptionCode) []byte {
-	return o[code.Code()]
+	for _, opt := range o.opts {
+		if opt.code == code.Code() {
+			return opt.value
+		}
+	}
+	return nil
 }
 
 // Has checks whether o has the given opcode.
 func (o Options) Has(opcode OptionCode) bool {
-	_, ok := o[opcode.Code()]
-	return ok
+	for _, opt := range o.opts {
+		if opt.code == opcode.Code() {
+			return true
+		}
+	}
+	return false
 }
 
 // Del deletes the option matching the option code.
-func (o Options) Del(opcode OptionCode) {
-	delete(o, opcode.Code())
+func (o *Options) Del(opcode OptionCode) {
+	for i, opt := range o.opts {
+		if opt.code == opcode.Code() {
+			o.opts = append(o.opts[:i], o.opts[i+1:]...)
+			return
+		}
+	}
 }
 
 // Update updates the existing options with the passed option, adding it
 // at the end if not present already
-func (o Options) Update(option Option) {
-	o[option.Code.Code()] = option.Value.ToBytes()
+func (o *Options) Update(option Option) {
+	// Avoid merging padding options
+	if option.Code.Code() != optPad {
+		for i, opt := range o.opts {
+			if opt.code == option.Code.Code() {
+				o.opts[i].value = option.Value.ToBytes()
+				return
+			}
+		}
+	}
+	o.opts = append(o.opts, optionCodeValue{option.Code.Code(), option.Value.ToBytes()})
 }
 
 // ToBytes makes Options usable as an OptionValue as well.
@@ -100,7 +140,7 @@ func (o Options) ToBytes() []byte {
 // The sequence should not contain the DHCP magic cookie.
 //
 // Returns an error if any invalid option or length is found.
-func (o Options) FromBytes(data []byte) error {
+func (o *Options) FromBytes(data []byte) error {
 	return o.fromBytesCheckEnd(data, false)
 }
 
@@ -112,7 +152,7 @@ const (
 
 // FromBytesCheckEnd parses Options from byte sequences using the
 // parsing function that is passed in as a paremeter
-func (o Options) fromBytesCheckEnd(data []byte, checkEndOption bool) error {
+func (o *Options) fromBytesCheckEnd(data []byte, checkEndOption bool) error {
 	if len(data) == 0 {
 		return nil
 	}
@@ -147,7 +187,18 @@ func (o Options) fromBytesCheckEnd(data []byte, checkEndOption bool) error {
 		//
 		// See also RFC 3396 for concatenation order and options longer
 		// than 255 bytes.
-		o[code] = append(o[code], data...)
+		var foundOpt int = -1
+		for i, opt := range o.opts {
+			if opt.code == code {
+				foundOpt = i
+				break
+			}
+		}
+		if foundOpt != -1 {
+			o.opts[foundOpt].value = append(o.opts[foundOpt].value, data...)
+		} else {
+			o.opts = append(o.opts, optionCodeValue{code, data})
+		}
 	}
 
 	// If we never read the End option, the sender of this packet screwed
@@ -163,45 +214,48 @@ func (o Options) fromBytesCheckEnd(data []byte, checkEndOption bool) error {
 // use in serializing options to binary.
 func (o Options) sortedKeys() []int {
 	// Send all values for a given key
-	var codes []int
-	var hasOptAgentInfo, hasOptEnd bool
-	for k := range o {
+	var indices []int
+	var optAgentInfoIndex int = -1
+	var optEndIndex int = -1
+	for i, opt := range o.opts {
 		// RFC 3046 section 2.1 states that option 82 SHALL come last (ignoring End).
-		if k == optAgentInfo {
-			hasOptAgentInfo = true
+		if opt.code == optAgentInfo {
+			optAgentInfoIndex = i
 			continue
 		}
-		if k == optEnd {
-			hasOptEnd = true
+		if opt.code == optEnd {
+			optEndIndex = i
 			continue
 		}
-		codes = append(codes, int(k))
+		indices = append(indices, int(i))
 	}
 
-	sort.Ints(codes)
-
-	if hasOptAgentInfo {
-		codes = append(codes, optAgentInfo)
+	if optAgentInfoIndex != -1 {
+		indices = append(indices, optAgentInfoIndex)
 	}
-	if hasOptEnd {
-		codes = append(codes, optEnd)
+	if optEndIndex != -1 {
+		indices = append(indices, optEndIndex)
 	}
-	return codes
+	return indices
 }
 
 // Marshal writes options binary representations to b.
 func (o Options) Marshal(b *uio.Lexer) {
 	for _, c := range o.sortedKeys() {
-		code := uint8(c)
+		code := uint8(o.opts[c].code)
 		// Even if the End option is in there, don't marshal it until
 		// the end.
-		// 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 {
+		if code == optEnd {
+			continue
+		}
+
+		// Padding does not have length
+		if code == optPad {
+			b.Write8(code)
 			continue
 		}
 
-		data := o[code]
+		data := o.opts[c].value
 
 		// Ensure even 0-length options are written out
 		if len(data) == 0 {
@@ -280,8 +334,8 @@ var dhcpHumanizer = OptionHumanizer{
 func (o Options) ToString(humanizer OptionHumanizer) string {
 	var ret string
 	for _, c := range o.sortedKeys() {
-		code := uint8(c)
-		v := o[code]
+		code := uint8(o.opts[c].code)
+		v := o.opts[c].value
 		optString := humanizer.Stringify(code, v)
 		// If this option has sub structures, offset them accordingly.
 		if strings.Contains(optString, "\n") {