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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"
"fmt"
"github.com/google/gopacket"
"strconv"
)
type ICMPv4TypeCode uint16
const (
ICMPv4TypeEchoReply = 0
ICMPv4TypeDestinationUnreachable = 3
ICMPv4TypeSourceQuench = 4
ICMPv4TypeRedirect = 5
ICMPv4TypeEchoRequest = 8
ICMPv4TypeRouterAdvertisement = 9
ICMPv4TypeRouterSolicitation = 10
ICMPv4TypeTimeExceeded = 11
ICMPv4TypeParameterProblem = 12
ICMPv4TypeTimestampRequest = 13
ICMPv4TypeTimestampReply = 14
ICMPv4TypeInfoRequest = 15
ICMPv4TypeInfoReply = 16
ICMPv4TypeAddressMaskRequest = 17
ICMPv4TypeAddressMaskReply = 18
)
// ICMPv4 is the layer for IPv4 ICMP packet data.
type ICMPv4 struct {
BaseLayer
TypeCode ICMPv4TypeCode
Checksum uint16
Id uint16
Seq uint16
}
// LayerType returns gopacket.LayerTypeICMPv4
func (i *ICMPv4) LayerType() gopacket.LayerType { return LayerTypeICMPv4 }
func decodeICMPv4(data []byte, p gopacket.PacketBuilder) error {
i := &ICMPv4{}
err := i.DecodeFromBytes(data, p)
if err != nil {
return err
}
p.AddLayer(i)
return p.NextDecoder(gopacket.LayerTypePayload)
}
var tooShort error = fmt.Errorf("icmp layer less than 8 bytes")
func (i *ICMPv4) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
if len(data) < 8 {
df.SetTruncated()
return tooShort
}
i.TypeCode = ICMPv4TypeCode(binary.BigEndian.Uint16(data[:2]))
i.Checksum = binary.BigEndian.Uint16(data[2:4])
i.Id = binary.BigEndian.Uint16(data[4:6])
i.Seq = binary.BigEndian.Uint16(data[6:8])
i.BaseLayer = BaseLayer{data[:8], data[8:]}
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 *ICMPv4) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
bytes, err := b.PrependBytes(8)
if err != nil {
return err
}
binary.BigEndian.PutUint16(bytes, uint16(i.TypeCode))
binary.BigEndian.PutUint16(bytes[4:], i.Id)
binary.BigEndian.PutUint16(bytes[6:], i.Seq)
if opts.ComputeChecksums {
bytes[2] = 0
bytes[3] = 0
i.Checksum = tcpipChecksum(b.Bytes(), 0)
}
binary.BigEndian.PutUint16(bytes[2:], i.Checksum)
return nil
}
func (i *ICMPv4) CanDecode() gopacket.LayerClass {
return LayerTypeICMPv4
}
func (i *ICMPv4) NextLayerType() gopacket.LayerType {
return gopacket.LayerTypePayload
}
func (a ICMPv4TypeCode) String() string {
typ := uint8(a >> 8)
code := uint8(a)
var typeStr, codeStr string
switch typ {
case ICMPv4TypeDestinationUnreachable:
typeStr = "DestinationUnreachable"
switch code {
case 0:
codeStr = "Net"
case 1:
codeStr = "Host"
case 2:
codeStr = "Protocol"
case 3:
codeStr = "Port"
case 4:
codeStr = "FragmentationNeeded"
case 5:
codeStr = "SourceRoutingFailed"
case 6:
codeStr = "NetUnknown"
case 7:
codeStr = "HostUnknown"
case 8:
codeStr = "SourceIsolated"
case 9:
codeStr = "NetAdminProhibited"
case 10:
codeStr = "HostAdminProhibited"
case 11:
codeStr = "NetTOS"
case 12:
codeStr = "HostTOS"
case 13:
codeStr = "CommAdminProhibited"
case 14:
codeStr = "HostPrecedence"
case 15:
codeStr = "PrecedenceCutoff"
}
case ICMPv4TypeTimeExceeded:
typeStr = "TimeExceeded"
switch code {
case 0:
codeStr = "TTLExceeded"
case 1:
codeStr = "FragmentReassemblyTimeExceeded"
}
case ICMPv4TypeParameterProblem:
typeStr = "ParameterProblem"
switch code {
case 0:
codeStr = "PointerIndicatesError"
case 1:
codeStr = "MissingOption"
case 2:
codeStr = "BadLength"
}
case ICMPv4TypeSourceQuench:
typeStr = "SourceQuench"
case ICMPv4TypeRedirect:
typeStr = "Redirect"
switch code {
case 0:
codeStr = "Network"
case 1:
codeStr = "Host"
case 2:
codeStr = "TOS+Network"
case 3:
codeStr = "TOS+Host"
}
case ICMPv4TypeEchoRequest:
typeStr = "EchoRequest"
case ICMPv4TypeEchoReply:
typeStr = "EchoReply"
case ICMPv4TypeTimestampRequest:
typeStr = "TimestampRequest"
case ICMPv4TypeTimestampReply:
typeStr = "TimestampReply"
case ICMPv4TypeInfoRequest:
typeStr = "InfoRequest"
case ICMPv4TypeInfoReply:
typeStr = "InfoReply"
case ICMPv4TypeRouterSolicitation:
typeStr = "RouterSolicitation"
case ICMPv4TypeRouterAdvertisement:
typeStr = "RouterAdvertisement"
case ICMPv4TypeAddressMaskRequest:
typeStr = "AddressMaskRequest"
case ICMPv4TypeAddressMaskReply:
typeStr = "AddressMaskReply"
default:
typeStr = strconv.Itoa(int(typ))
}
if codeStr == "" {
codeStr = strconv.Itoa(int(code))
}
return fmt.Sprintf("%s(%s)", typeStr, codeStr)
}
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