TUN-6666: Define packet package

This package defines IP and ICMP packet, decoders, encoder and flow

vendor/github.com/google/gopacket/layers/mldv1.go

@@ -0,0 +1,182 @@
+// Copyright 2018 GoPacket Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+package layers
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math"
+	"net"
+	"time"
+
+	"github.com/google/gopacket"
+)
+
+// MLDv1Message represents the common structure of all MLDv1 messages
+type MLDv1Message struct {
+	BaseLayer
+	// 3.4. Maximum Response Delay
+	MaximumResponseDelay time.Duration
+	// 3.6. Multicast Address
+	// Zero in general query
+	// Specific IPv6 multicast address otherwise
+	MulticastAddress net.IP
+}
+
+// DecodeFromBytes decodes the given bytes into this layer.
+func (m *MLDv1Message) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
+	if len(data) < 20 {
+		df.SetTruncated()
+		return errors.New("ICMP layer less than 20 bytes for Multicast Listener Query Message V1")
+	}
+
+	m.MaximumResponseDelay = time.Duration(binary.BigEndian.Uint16(data[0:2])) * time.Millisecond
+	// data[2:4] is reserved and not used in mldv1
+	m.MulticastAddress = data[4:20]
+
+	return nil
+}
+
+// NextLayerType returns the layer type contained by this DecodingLayer.
+func (*MLDv1Message) NextLayerType() gopacket.LayerType {
+	return gopacket.LayerTypeZero
+}
+
+// SerializeTo writes the serialized form of this layer into the
+// SerializationBuffer, implementing gopacket.SerializableLayer.
+// See the docs for gopacket.SerializableLayer for more info.
+func (m *MLDv1Message) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	buf, err := b.PrependBytes(20)
+	if err != nil {
+		return err
+	}
+
+	if m.MaximumResponseDelay < 0 {
+		return errors.New("maximum response delay must not be negative")
+	}
+	dms := m.MaximumResponseDelay / time.Millisecond
+	if dms > math.MaxUint16 {
+		return fmt.Errorf("maximum response delay %dms is more than the allowed 65535ms", dms)
+	}
+	binary.BigEndian.PutUint16(buf[0:2], uint16(dms))
+
+	copy(buf[2:4], []byte{0x0, 0x0})
+
+	ma16 := m.MulticastAddress.To16()
+	if ma16 == nil {
+		return fmt.Errorf("invalid multicast address '%s'", m.MulticastAddress)
+	}
+	copy(buf[4:20], ma16)
+
+	return nil
+}
+
+// Sums this layer up nicely formatted
+func (m *MLDv1Message) String() string {
+	return fmt.Sprintf(
+		"Maximum Response Delay: %dms, Multicast Address: %s",
+		m.MaximumResponseDelay/time.Millisecond,
+		m.MulticastAddress)
+}
+
+// MLDv1MulticastListenerQueryMessage are sent by the router to determine
+// whether there are multicast listeners on the link.
+// https://tools.ietf.org/html/rfc2710 Page 5
+type MLDv1MulticastListenerQueryMessage struct {
+	MLDv1Message
+}
+
+// DecodeFromBytes decodes the given bytes into this layer.
+func (m *MLDv1MulticastListenerQueryMessage) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
+	err := m.MLDv1Message.DecodeFromBytes(data, df)
+	if err != nil {
+		return err
+	}
+
+	if len(data) > 20 {
+		m.Payload = data[20:]
+	}
+
+	return nil
+}
+
+// LayerType returns LayerTypeMLDv1MulticastListenerQuery.
+func (*MLDv1MulticastListenerQueryMessage) LayerType() gopacket.LayerType {
+	return LayerTypeMLDv1MulticastListenerQuery
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode.
+func (*MLDv1MulticastListenerQueryMessage) CanDecode() gopacket.LayerClass {
+	return LayerTypeMLDv1MulticastListenerQuery
+}
+
+// IsGeneralQuery is true when this is a general query.
+// In a Query message, the Multicast Address field is set to zero when
+// sending a General Query.
+// https://tools.ietf.org/html/rfc2710#section-3.6
+func (m *MLDv1MulticastListenerQueryMessage) IsGeneralQuery() bool {
+	return net.IPv6zero.Equal(m.MulticastAddress)
+}
+
+// IsSpecificQuery is true when this is not a general query.
+// In a Query message, the Multicast Address field is set to a specific
+// IPv6 multicast address when sending a Multicast-Address-Specific Query.
+// https://tools.ietf.org/html/rfc2710#section-3.6
+func (m *MLDv1MulticastListenerQueryMessage) IsSpecificQuery() bool {
+	return !m.IsGeneralQuery()
+}
+
+// MLDv1MulticastListenerReportMessage is sent by a client listening on
+// a specific multicast address to indicate that it is (still) listening
+// on the specific multicast address.
+// https://tools.ietf.org/html/rfc2710 Page 6
+type MLDv1MulticastListenerReportMessage struct {
+	MLDv1Message
+}
+
+// LayerType returns LayerTypeMLDv1MulticastListenerReport.
+func (*MLDv1MulticastListenerReportMessage) LayerType() gopacket.LayerType {
+	return LayerTypeMLDv1MulticastListenerReport
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode.
+func (*MLDv1MulticastListenerReportMessage) CanDecode() gopacket.LayerClass {
+	return LayerTypeMLDv1MulticastListenerReport
+}
+
+// MLDv1MulticastListenerDoneMessage should be sent by a client when it ceases
+// to listen to a multicast address on an interface.
+// https://tools.ietf.org/html/rfc2710 Page 7
+type MLDv1MulticastListenerDoneMessage struct {
+	MLDv1Message
+}
+
+// LayerType returns LayerTypeMLDv1MulticastListenerDone.
+func (*MLDv1MulticastListenerDoneMessage) LayerType() gopacket.LayerType {
+	return LayerTypeMLDv1MulticastListenerDone
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode.
+func (*MLDv1MulticastListenerDoneMessage) CanDecode() gopacket.LayerClass {
+	return LayerTypeMLDv1MulticastListenerDone
+}
+
+func decodeMLDv1MulticastListenerReport(data []byte, p gopacket.PacketBuilder) error {
+	m := &MLDv1MulticastListenerReportMessage{}
+	return decodingLayerDecoder(m, data, p)
+}
+
+func decodeMLDv1MulticastListenerQuery(data []byte, p gopacket.PacketBuilder) error {
+	m := &MLDv1MulticastListenerQueryMessage{}
+	return decodingLayerDecoder(m, data, p)
+}
+
+func decodeMLDv1MulticastListenerDone(data []byte, p gopacket.PacketBuilder) error {
+	m := &MLDv1MulticastListenerDoneMessage{}
+	return decodingLayerDecoder(m, data, p)
+}