78 lines
2.2 KiB
Go
78 lines
2.2 KiB
Go
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// Copyright 2012 Google, Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree.
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package layers
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import (
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"encoding/binary"
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"errors"
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"github.com/google/gopacket"
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)
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// IPSecAH is the authentication header for IPv4/6 defined in
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// http://tools.ietf.org/html/rfc2402
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type IPSecAH struct {
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// While the auth header can be used for both IPv4 and v6, its format is that of
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// an IPv6 extension (NextHeader, PayloadLength, etc...), so we use ipv6ExtensionBase
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// to build it.
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ipv6ExtensionBase
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Reserved uint16
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SPI, Seq uint32
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AuthenticationData []byte
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}
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// LayerType returns LayerTypeIPSecAH.
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func (i *IPSecAH) LayerType() gopacket.LayerType { return LayerTypeIPSecAH }
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func decodeIPSecAH(data []byte, p gopacket.PacketBuilder) error {
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if len(data) < 12 {
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p.SetTruncated()
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return errors.New("IPSec AH packet less than 12 bytes")
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}
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i := &IPSecAH{
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ipv6ExtensionBase: ipv6ExtensionBase{
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NextHeader: IPProtocol(data[0]),
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HeaderLength: data[1],
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},
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Reserved: binary.BigEndian.Uint16(data[2:4]),
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SPI: binary.BigEndian.Uint32(data[4:8]),
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Seq: binary.BigEndian.Uint32(data[8:12]),
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}
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i.ActualLength = (int(i.HeaderLength) + 2) * 4
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if len(data) < i.ActualLength {
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p.SetTruncated()
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return errors.New("Truncated AH packet < ActualLength")
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}
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i.AuthenticationData = data[12:i.ActualLength]
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i.Contents = data[:i.ActualLength]
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i.Payload = data[i.ActualLength:]
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p.AddLayer(i)
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return p.NextDecoder(i.NextHeader)
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}
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// IPSecESP is the encapsulating security payload defined in
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// http://tools.ietf.org/html/rfc2406
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type IPSecESP struct {
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BaseLayer
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SPI, Seq uint32
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// Encrypted contains the encrypted set of bytes sent in an ESP
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Encrypted []byte
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}
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// LayerType returns LayerTypeIPSecESP.
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func (i *IPSecESP) LayerType() gopacket.LayerType { return LayerTypeIPSecESP }
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func decodeIPSecESP(data []byte, p gopacket.PacketBuilder) error {
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i := &IPSecESP{
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BaseLayer: BaseLayer{data, nil},
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SPI: binary.BigEndian.Uint32(data[:4]),
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Seq: binary.BigEndian.Uint32(data[4:8]),
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Encrypted: data[8:],
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}
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p.AddLayer(i)
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return nil
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}
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