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

   1 // Copyright 2012 Google, Inc. All rights reserved.
   2 //
   3 // Use of this source code is governed by a BSD-style license
   4 // that can be found in the LICENSE file in the root of the source
   5 // tree.
   6
   7 package layers
   8
   9 import (
  10         "encoding/binary"
  11         "github.com/google/gopacket"
  12 )
  13
  14 // IPSecAH is the authentication header for IPv4/6 defined in
  15 // http://tools.ietf.org/html/rfc2402
  16 type IPSecAH struct {
  17         // While the auth header can be used for both IPv4 and v6, its format is that of
  18         // an IPv6 extension (NextHeader, PayloadLength, etc...), so we use ipv6ExtensionBase
  19         // to build it.
  20         ipv6ExtensionBase
  21         Reserved           uint16
  22         SPI, Seq           uint32
  23         AuthenticationData []byte
  24 }
  25
  26 // LayerType returns LayerTypeIPSecAH.
  27 func (i *IPSecAH) LayerType() gopacket.LayerType { return LayerTypeIPSecAH }
  28
  29 func decodeIPSecAH(data []byte, p gopacket.PacketBuilder) error {
  30         i := &IPSecAH{
  31                 ipv6ExtensionBase: ipv6ExtensionBase{
  32                         NextHeader:   IPProtocol(data[0]),
  33                         HeaderLength: data[1],
  34                 },
  35                 Reserved: binary.BigEndian.Uint16(data[2:4]),
  36                 SPI:      binary.BigEndian.Uint32(data[4:8]),
  37                 Seq:      binary.BigEndian.Uint32(data[8:12]),
  38         }
  39         i.ActualLength = (int(i.HeaderLength) + 2) * 4
  40         i.AuthenticationData = data[12:i.ActualLength]
  41         i.Contents = data[:i.ActualLength]
  42         i.Payload = data[i.ActualLength:]
  43         p.AddLayer(i)
  44         return p.NextDecoder(i.NextHeader)
  45 }
  46
  47 // IPSecESP is the encapsulating security payload defined in
  48 // http://tools.ietf.org/html/rfc2406
  49 type IPSecESP struct {
  50         BaseLayer
  51         SPI, Seq uint32
  52         // Encrypted contains the encrypted set of bytes sent in an ESP
  53         Encrypted []byte
  54 }
  55
  56 // LayerType returns LayerTypeIPSecESP.
  57 func (i *IPSecESP) LayerType() gopacket.LayerType { return LayerTypeIPSecESP }
  58
  59 func decodeIPSecESP(data []byte, p gopacket.PacketBuilder) error {
  60         i := &IPSecESP{
  61                 BaseLayer: BaseLayer{data, nil},
  62                 SPI:       binary.BigEndian.Uint32(data[:4]),
  63                 Seq:       binary.BigEndian.Uint32(data[4:8]),
  64                 Encrypted: data[8:],
  65         }
  66         p.AddLayer(i)
  67         return nil
  68 }