61 lines
1.6 KiB
Go
61 lines
1.6 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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"github.com/google/gopacket"
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)
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// PPPoE is the layer for PPPoE encapsulation headers.
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type PPPoE struct {
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BaseLayer
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Version uint8
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Type uint8
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Code PPPoECode
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SessionId uint16
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Length uint16
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}
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// LayerType returns gopacket.LayerTypePPPoE.
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func (p *PPPoE) LayerType() gopacket.LayerType {
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return LayerTypePPPoE
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}
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// decodePPPoE decodes the PPPoE header (see http://tools.ietf.org/html/rfc2516).
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func decodePPPoE(data []byte, p gopacket.PacketBuilder) error {
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pppoe := &PPPoE{
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Version: data[0] >> 4,
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Type: data[0] & 0x0F,
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Code: PPPoECode(data[1]),
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SessionId: binary.BigEndian.Uint16(data[2:4]),
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Length: binary.BigEndian.Uint16(data[4:6]),
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}
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pppoe.BaseLayer = BaseLayer{data[:6], data[6 : 6+pppoe.Length]}
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p.AddLayer(pppoe)
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return p.NextDecoder(pppoe.Code)
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}
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// SerializeTo writes the serialized form of this layer into the
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// SerializationBuffer, implementing gopacket.SerializableLayer.
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// See the docs for gopacket.SerializableLayer for more info.
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func (p *PPPoE) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
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payload := b.Bytes()
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bytes, err := b.PrependBytes(6)
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if err != nil {
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return err
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}
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bytes[0] = (p.Version << 4) | p.Type
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bytes[1] = byte(p.Code)
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binary.BigEndian.PutUint16(bytes[2:], p.SessionId)
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if opts.FixLengths {
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p.Length = uint16(len(payload))
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}
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binary.BigEndian.PutUint16(bytes[4:], p.Length)
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return nil
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}
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