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// Copyright 2012 Google, Inc. All rights reserved.
// Copyright 2009-2011 Andreas Krennmair. 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"
"encoding/hex"
"errors"
"fmt"
"net"
"time"
"github.com/google/gopacket"
)
// Based on RFC 4861
// ICMPv6Opt indicate how to decode the data associated with each ICMPv6Option.
type ICMPv6Opt uint8
const (
_ ICMPv6Opt = iota
// ICMPv6OptSourceAddress contains the link-layer address of the sender of
// the packet. It is used in the Neighbor Solicitation, Router
// Solicitation, and Router Advertisement packets. Must be ignored for other
// Neighbor discovery messages.
ICMPv6OptSourceAddress
// ICMPv6OptTargetAddress contains the link-layer address of the target. It
// is used in Neighbor Advertisement and Redirect packets. Must be ignored
// for other Neighbor discovery messages.
ICMPv6OptTargetAddress
// ICMPv6OptPrefixInfo provides hosts with on-link prefixes and prefixes
// for Address Autoconfiguration. The Prefix Information option appears in
// Router Advertisement packets and MUST be silently ignored for other
// messages.
ICMPv6OptPrefixInfo
// ICMPv6OptRedirectedHeader is used in Redirect messages and contains all
// or part of the packet that is being redirected.
ICMPv6OptRedirectedHeader
// ICMPv6OptMTU is used in Router Advertisement messages to ensure that all
// nodes on a link use the same MTU value in those cases where the link MTU
// is not well known. This option MUST be silently ignored for other
// Neighbor Discovery messages.
ICMPv6OptMTU
)
// ICMPv6Echo represents the structure of a ping.
type ICMPv6Echo struct {
BaseLayer
Identifier uint16
SeqNumber uint16
}
// ICMPv6RouterSolicitation is sent by hosts to find routers.
type ICMPv6RouterSolicitation struct {
BaseLayer
Options ICMPv6Options
}
// ICMPv6RouterAdvertisement is sent by routers in response to Solicitation.
type ICMPv6RouterAdvertisement struct {
BaseLayer
HopLimit uint8
Flags uint8
RouterLifetime uint16
ReachableTime uint32
RetransTimer uint32
Options ICMPv6Options
}
// ICMPv6NeighborSolicitation is sent to request the link-layer address of a
// target node.
type ICMPv6NeighborSolicitation struct {
BaseLayer
TargetAddress net.IP
Options ICMPv6Options
}
// ICMPv6NeighborAdvertisement is sent by nodes in response to Solicitation.
type ICMPv6NeighborAdvertisement struct {
BaseLayer
Flags uint8
TargetAddress net.IP
Options ICMPv6Options
}
// ICMPv6Redirect is sent by routers to inform hosts of a better first-hop node
// on the path to a destination.
type ICMPv6Redirect struct {
BaseLayer
TargetAddress net.IP
DestinationAddress net.IP
Options ICMPv6Options
}
// ICMPv6Option contains the type and data for a single option.
type ICMPv6Option struct {
Type ICMPv6Opt
Data []byte
}
// ICMPv6Options is a slice of ICMPv6Option.
type ICMPv6Options []ICMPv6Option
func (i ICMPv6Opt) String() string {
switch i {
case ICMPv6OptSourceAddress:
return "SourceAddress"
case ICMPv6OptTargetAddress:
return "TargetAddress"
case ICMPv6OptPrefixInfo:
return "PrefixInfo"
case ICMPv6OptRedirectedHeader:
return "RedirectedHeader"
case ICMPv6OptMTU:
return "MTU"
default:
return fmt.Sprintf("Unknown(%d)", i)
}
}
// CanDecode returns the set of layer types that this DecodingLayer can decode.
func (i *ICMPv6Echo) CanDecode() gopacket.LayerClass {
return LayerTypeICMPv6Echo
}
// LayerType returns LayerTypeICMPv6Echo.
func (i *ICMPv6Echo) LayerType() gopacket.LayerType {
return LayerTypeICMPv6Echo
}
// NextLayerType returns the layer type contained by this DecodingLayer.
func (i *ICMPv6Echo) NextLayerType() gopacket.LayerType {
return gopacket.LayerTypePayload
}
// DecodeFromBytes decodes the given bytes into this layer.
func (i *ICMPv6Echo) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
if len(data) < 4 {
df.SetTruncated()
return errors.New("ICMP layer less then 4 bytes for ICMPv6 Echo")
}
i.Identifier = binary.BigEndian.Uint16(data[0:2])
i.SeqNumber = binary.BigEndian.Uint16(data[2:4])
return nil
}
// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.
// See the docs for gopacket.SerializableLayer for more info.
func (i *ICMPv6Echo) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
buf, err := b.PrependBytes(4)
if err != nil {
return err
}
binary.BigEndian.PutUint16(buf, i.Identifier)
binary.BigEndian.PutUint16(buf[2:], i.SeqNumber)
return nil
}
// LayerType returns LayerTypeICMPv6.
func (i *ICMPv6RouterSolicitation) LayerType() gopacket.LayerType {
return LayerTypeICMPv6RouterSolicitation
}
// NextLayerType returns the layer type contained by this DecodingLayer.
func (i *ICMPv6RouterSolicitation) NextLayerType() gopacket.LayerType {
return gopacket.LayerTypePayload
}
// DecodeFromBytes decodes the given bytes into this layer.
func (i *ICMPv6RouterSolicitation) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
// first 4 bytes are reserved followed by options
if len(data) < 4 {
df.SetTruncated()
return errors.New("ICMP layer less then 4 bytes for ICMPv6 router solicitation")
}
// truncate old options
i.Options = i.Options[:0]
return i.Options.DecodeFromBytes(data[4:], df)
}
// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.
// See the docs for gopacket.SerializableLayer for more info.
func (i *ICMPv6RouterSolicitation) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
if err := i.Options.SerializeTo(b, opts); err != nil {
return err
}
buf, err := b.PrependBytes(4)
if err != nil {
return err
}
copy(buf, lotsOfZeros[:4])
return nil
}
// CanDecode returns the set of layer types that this DecodingLayer can decode.
func (i *ICMPv6RouterSolicitation) CanDecode() gopacket.LayerClass {
return LayerTypeICMPv6RouterSolicitation
}
// LayerType returns LayerTypeICMPv6RouterAdvertisement.
func (i *ICMPv6RouterAdvertisement) LayerType() gopacket.LayerType {
return LayerTypeICMPv6RouterAdvertisement
}
// NextLayerType returns the layer type contained by this DecodingLayer.
func (i *ICMPv6RouterAdvertisement) NextLayerType() gopacket.LayerType {
return gopacket.LayerTypePayload
}
// DecodeFromBytes decodes the given bytes into this layer.
func (i *ICMPv6RouterAdvertisement) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
if len(data) < 12 {
df.SetTruncated()
return errors.New("ICMP layer less then 12 bytes for ICMPv6 router advertisement")
}
i.HopLimit = uint8(data[0])
// M, O bit followed by 6 reserved bits
i.Flags = uint8(data[1])
i.RouterLifetime = binary.BigEndian.Uint16(data[2:4])
i.ReachableTime = binary.BigEndian.Uint32(data[4:8])
i.RetransTimer = binary.BigEndian.Uint32(data[8:12])
i.BaseLayer = BaseLayer{data, nil} // assume no payload
// truncate old options
i.Options = i.Options[:0]
return i.Options.DecodeFromBytes(data[12:], df)
}
// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.
// See the docs for gopacket.SerializableLayer for more info.
func (i *ICMPv6RouterAdvertisement) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
if err := i.Options.SerializeTo(b, opts); err != nil {
return err
}
buf, err := b.PrependBytes(12)
if err != nil {
return err
}
buf[0] = byte(i.HopLimit)
buf[1] = byte(i.Flags)
binary.BigEndian.PutUint16(buf[2:], i.RouterLifetime)
binary.BigEndian.PutUint32(buf[4:], i.ReachableTime)
binary.BigEndian.PutUint32(buf[8:], i.RetransTimer)
return nil
}
// CanDecode returns the set of layer types that this DecodingLayer can decode.
func (i *ICMPv6RouterAdvertisement) CanDecode() gopacket.LayerClass {
return LayerTypeICMPv6RouterAdvertisement
}
// ManagedAddressConfig is true when addresses are available via DHCPv6. If
// set, the OtherConfig flag is redundant.
func (i *ICMPv6RouterAdvertisement) ManagedAddressConfig() bool {
return i.Flags&0x80 != 0
}
// OtherConfig is true when there is other configuration information available
// via DHCPv6. For example, DNS-related information.
func (i *ICMPv6RouterAdvertisement) OtherConfig() bool {
return i.Flags&0x40 != 0
}
// LayerType returns LayerTypeICMPv6NeighborSolicitation.
func (i *ICMPv6NeighborSolicitation) LayerType() gopacket.LayerType {
return LayerTypeICMPv6NeighborSolicitation
}
// NextLayerType returns the layer type contained by this DecodingLayer.
func (i *ICMPv6NeighborSolicitation) NextLayerType() gopacket.LayerType {
return gopacket.LayerTypePayload
}
// DecodeFromBytes decodes the given bytes into this layer.
func (i *ICMPv6NeighborSolicitation) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
if len(data) < 20 {
df.SetTruncated()
return errors.New("ICMP layer less then 20 bytes for ICMPv6 neighbor solicitation")
}
i.TargetAddress = net.IP(data[4:20])
i.BaseLayer = BaseLayer{data, nil} // assume no payload
// truncate old options
i.Options = i.Options[:0]
return i.Options.DecodeFromBytes(data[20:], df)
}
// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.
// See the docs for gopacket.SerializableLayer for more info.
func (i *ICMPv6NeighborSolicitation) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
if err := i.Options.SerializeTo(b, opts); err != nil {
return err
}
buf, err := b.PrependBytes(20)
if err != nil {
return err
}
copy(buf, lotsOfZeros[:4])
copy(buf[4:], i.TargetAddress)
return nil
}
// CanDecode returns the set of layer types that this DecodingLayer can decode.
func (i *ICMPv6NeighborSolicitation) CanDecode() gopacket.LayerClass {
return LayerTypeICMPv6NeighborSolicitation
}
// LayerType returns LayerTypeICMPv6NeighborAdvertisement.
func (i *ICMPv6NeighborAdvertisement) LayerType() gopacket.LayerType {
return LayerTypeICMPv6NeighborAdvertisement
}
// NextLayerType returns the layer type contained by this DecodingLayer.
func (i *ICMPv6NeighborAdvertisement) NextLayerType() gopacket.LayerType {
return gopacket.LayerTypePayload
}
// DecodeFromBytes decodes the given bytes into this layer.
func (i *ICMPv6NeighborAdvertisement) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
if len(data) < 20 {
df.SetTruncated()
return errors.New("ICMP layer less then 20 bytes for ICMPv6 neighbor advertisement")
}
i.Flags = uint8(data[0])
i.TargetAddress = net.IP(data[4:20])
i.BaseLayer = BaseLayer{data, nil} // assume no payload
// truncate old options
i.Options = i.Options[:0]
return i.Options.DecodeFromBytes(data[20:], df)
}
// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.
// See the docs for gopacket.SerializableLayer for more info.
func (i *ICMPv6NeighborAdvertisement) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
if err := i.Options.SerializeTo(b, opts); err != nil {
return err
}
buf, err := b.PrependBytes(20)
if err != nil {
return err
}
buf[0] = byte(i.Flags)
copy(buf[1:], lotsOfZeros[:3])
copy(buf[4:], i.TargetAddress)
return nil
}
// CanDecode returns the set of layer types that this DecodingLayer can decode.
func (i *ICMPv6NeighborAdvertisement) CanDecode() gopacket.LayerClass {
return LayerTypeICMPv6NeighborAdvertisement
}
// Router indicates whether the sender is a router or not.
func (i *ICMPv6NeighborAdvertisement) Router() bool {
return i.Flags&0x80 != 0
}
// Solicited indicates whether the advertisement was solicited or not.
func (i *ICMPv6NeighborAdvertisement) Solicited() bool {
return i.Flags&0x40 != 0
}
// Override indicates whether the advertisement should Override an existing
// cache entry.
func (i *ICMPv6NeighborAdvertisement) Override() bool {
return i.Flags&0x20 != 0
}
// LayerType returns LayerTypeICMPv6Redirect.
func (i *ICMPv6Redirect) LayerType() gopacket.LayerType {
return LayerTypeICMPv6Redirect
}
// NextLayerType returns the layer type contained by this DecodingLayer.
func (i *ICMPv6Redirect) NextLayerType() gopacket.LayerType {
return gopacket.LayerTypePayload
}
// DecodeFromBytes decodes the given bytes into this layer.
func (i *ICMPv6Redirect) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
if len(data) < 36 {
df.SetTruncated()
return errors.New("ICMP layer less then 36 bytes for ICMPv6 redirect")
}
i.TargetAddress = net.IP(data[4:20])
i.DestinationAddress = net.IP(data[20:36])
i.BaseLayer = BaseLayer{data, nil} // assume no payload
// truncate old options
i.Options = i.Options[:0]
return i.Options.DecodeFromBytes(data[36:], df)
}
// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.
// See the docs for gopacket.SerializableLayer for more info.
func (i *ICMPv6Redirect) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
if err := i.Options.SerializeTo(b, opts); err != nil {
return err
}
buf, err := b.PrependBytes(36)
if err != nil {
return err
}
copy(buf, lotsOfZeros[:4])
copy(buf[4:], i.TargetAddress)
copy(buf[20:], i.DestinationAddress)
return nil
}
// CanDecode returns the set of layer types that this DecodingLayer can decode.
func (i *ICMPv6Redirect) CanDecode() gopacket.LayerClass {
return LayerTypeICMPv6Redirect
}
func (i ICMPv6Option) String() string {
hd := hex.EncodeToString(i.Data)
if len(hd) > 0 {
hd = " 0x" + hd
}
switch i.Type {
case ICMPv6OptSourceAddress, ICMPv6OptTargetAddress:
return fmt.Sprintf("ICMPv6Option(%s:%v)",
i.Type,
net.HardwareAddr(i.Data))
case ICMPv6OptPrefixInfo:
if len(i.Data) == 30 {
prefixLen := uint8(i.Data[0])
onLink := (i.Data[1]&0x80 != 0)
autonomous := (i.Data[1]&0x40 != 0)
validLifetime := time.Duration(binary.BigEndian.Uint32(i.Data[2:6])) * time.Second
preferredLifetime := time.Duration(binary.BigEndian.Uint32(i.Data[6:10])) * time.Second
prefix := net.IP(i.Data[14:])
return fmt.Sprintf("ICMPv6Option(%s:%v/%v:%t:%t:%v:%v)",
i.Type,
prefix, prefixLen,
onLink, autonomous,
validLifetime, preferredLifetime)
}
case ICMPv6OptRedirectedHeader:
// could invoke IP decoder on data... probably best not to
break
case ICMPv6OptMTU:
if len(i.Data) == 6 {
return fmt.Sprintf("ICMPv6Option(%s:%v)",
i.Type,
binary.BigEndian.Uint32(i.Data[2:]))
}
}
return fmt.Sprintf("ICMPv6Option(%s:%s)", i.Type, hd)
}
// DecodeFromBytes decodes the given bytes into this layer.
func (i *ICMPv6Options) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
for len(data) > 0 {
if len(data) < 2 {
df.SetTruncated()
return errors.New("ICMP layer less then 2 bytes for ICMPv6 message option")
}
// unit is 8 octets, convert to bytes
length := int(data[1]) * 8
if length == 0 {
df.SetTruncated()
return errors.New("ICMPv6 message option with length 0")
}
if len(data) < length {
df.SetTruncated()
return fmt.Errorf("ICMP layer only %v bytes for ICMPv6 message option with length %v", len(data), length)
}
o := ICMPv6Option{
Type: ICMPv6Opt(data[0]),
Data: data[2:length],
}
// chop off option we just consumed
data = data[length:]
*i = append(*i, o)
}
return nil
}
// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.
// See the docs for gopacket.SerializableLayer for more info.
func (i *ICMPv6Options) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
for _, opt := range []ICMPv6Option(*i) {
length := len(opt.Data) + 2
buf, err := b.PrependBytes(length)
if err != nil {
return err
}
buf[0] = byte(opt.Type)
buf[1] = byte(length / 8)
copy(buf[2:], opt.Data)
}
return nil
}
func decodeICMPv6Echo(data []byte, p gopacket.PacketBuilder) error {
i := &ICMPv6Echo{}
return decodingLayerDecoder(i, data, p)
}
func decodeICMPv6RouterSolicitation(data []byte, p gopacket.PacketBuilder) error {
i := &ICMPv6RouterSolicitation{}
return decodingLayerDecoder(i, data, p)
}
func decodeICMPv6RouterAdvertisement(data []byte, p gopacket.PacketBuilder) error {
i := &ICMPv6RouterAdvertisement{}
return decodingLayerDecoder(i, data, p)
}
func decodeICMPv6NeighborSolicitation(data []byte, p gopacket.PacketBuilder) error {
i := &ICMPv6NeighborSolicitation{}
return decodingLayerDecoder(i, data, p)
}
func decodeICMPv6NeighborAdvertisement(data []byte, p gopacket.PacketBuilder) error {
i := &ICMPv6NeighborAdvertisement{}
return decodingLayerDecoder(i, data, p)
}
func decodeICMPv6Redirect(data []byte, p gopacket.PacketBuilder) error {
i := &ICMPv6Redirect{}
return decodingLayerDecoder(i, data, p)
}