TUN-6666: Define packet package

This package defines IP and ICMP packet, decoders, encoder and flow

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

@@ -0,0 +1,60 @@
+// 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"
+)
+
+// PPPoE is the layer for PPPoE encapsulation headers.
+type PPPoE struct {
+	BaseLayer
+	Version   uint8
+	Type      uint8
+	Code      PPPoECode
+	SessionId uint16
+	Length    uint16
+}
+
+// LayerType returns gopacket.LayerTypePPPoE.
+func (p *PPPoE) LayerType() gopacket.LayerType {
+	return LayerTypePPPoE
+}
+
+// decodePPPoE decodes the PPPoE header (see http://tools.ietf.org/html/rfc2516).
+func decodePPPoE(data []byte, p gopacket.PacketBuilder) error {
+	pppoe := &PPPoE{
+		Version:   data[0] >> 4,
+		Type:      data[0] & 0x0F,
+		Code:      PPPoECode(data[1]),
+		SessionId: binary.BigEndian.Uint16(data[2:4]),
+		Length:    binary.BigEndian.Uint16(data[4:6]),
+	}
+	pppoe.BaseLayer = BaseLayer{data[:6], data[6 : 6+pppoe.Length]}
+	p.AddLayer(pppoe)
+	return p.NextDecoder(pppoe.Code)
+}
+
+// SerializeTo writes the serialized form of this layer into the
+// SerializationBuffer, implementing gopacket.SerializableLayer.
+// See the docs for gopacket.SerializableLayer for more info.
+func (p *PPPoE) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	payload := b.Bytes()
+	bytes, err := b.PrependBytes(6)
+	if err != nil {
+		return err
+	}
+	bytes[0] = (p.Version << 4) | p.Type
+	bytes[1] = byte(p.Code)
+	binary.BigEndian.PutUint16(bytes[2:], p.SessionId)
+	if opts.FixLengths {
+		p.Length = uint16(len(payload))
+	}
+	binary.BigEndian.PutUint16(bytes[4:], p.Length)
+	return nil
+}