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// Copyright 2012 Google, Inc. 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"
"github.com/google/gopacket"
)
// IPSecAH is the authentication header for IPv4/6 defined in
// http://tools.ietf.org/html/rfc2402
type IPSecAH struct {
// While the auth header can be used for both IPv4 and v6, its format is that of
// an IPv6 extension (NextHeader, PayloadLength, etc...), so we use ipv6ExtensionBase
// to build it.
ipv6ExtensionBase
Reserved uint16
SPI, Seq uint32
AuthenticationData []byte
}
// LayerType returns LayerTypeIPSecAH.
func (i *IPSecAH) LayerType() gopacket.LayerType { return LayerTypeIPSecAH }
func decodeIPSecAH(data []byte, p gopacket.PacketBuilder) error {
i := &IPSecAH{
ipv6ExtensionBase: ipv6ExtensionBase{
NextHeader: IPProtocol(data[0]),
HeaderLength: data[1],
},
Reserved: binary.BigEndian.Uint16(data[2:4]),
SPI: binary.BigEndian.Uint32(data[4:8]),
Seq: binary.BigEndian.Uint32(data[8:12]),
}
i.ActualLength = (int(i.HeaderLength) + 2) * 4
i.AuthenticationData = data[12:i.ActualLength]
i.Contents = data[:i.ActualLength]
i.Payload = data[i.ActualLength:]
p.AddLayer(i)
return p.NextDecoder(i.NextHeader)
}
// IPSecESP is the encapsulating security payload defined in
// http://tools.ietf.org/html/rfc2406
type IPSecESP struct {
BaseLayer
SPI, Seq uint32
// Encrypted contains the encrypted set of bytes sent in an ESP
Encrypted []byte
}
// LayerType returns LayerTypeIPSecESP.
func (i *IPSecESP) LayerType() gopacket.LayerType { return LayerTypeIPSecESP }
func decodeIPSecESP(data []byte, p gopacket.PacketBuilder) error {
i := &IPSecESP{
BaseLayer: BaseLayer{data, nil},
SPI: binary.BigEndian.Uint32(data[:4]),
Seq: binary.BigEndian.Uint32(data[4:8]),
Encrypted: data[8:],
}
p.AddLayer(i)
return nil
}