TUN-6666: Define packet package

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

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

@@ -0,0 +1,109 @@
+// 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"
+	"fmt"
+	"github.com/google/gopacket"
+)
+
+// EthernetCTPFunction is the function code used by the EthernetCTP protocol to identify each
+// EthernetCTP layer.
+type EthernetCTPFunction uint16
+
+// EthernetCTPFunction values.
+const (
+	EthernetCTPFunctionReply       EthernetCTPFunction = 1
+	EthernetCTPFunctionForwardData EthernetCTPFunction = 2
+)
+
+// EthernetCTP implements the EthernetCTP protocol, see http://www.mit.edu/people/jhawk/ctp.html.
+// We split EthernetCTP up into the top-level EthernetCTP layer, followed by zero or more
+// EthernetCTPForwardData layers, followed by a final EthernetCTPReply layer.
+type EthernetCTP struct {
+	BaseLayer
+	SkipCount uint16
+}
+
+// LayerType returns gopacket.LayerTypeEthernetCTP.
+func (c *EthernetCTP) LayerType() gopacket.LayerType {
+	return LayerTypeEthernetCTP
+}
+
+// EthernetCTPForwardData is the ForwardData layer inside EthernetCTP.  See EthernetCTP's docs for more
+// details.
+type EthernetCTPForwardData struct {
+	BaseLayer
+	Function       EthernetCTPFunction
+	ForwardAddress []byte
+}
+
+// LayerType returns gopacket.LayerTypeEthernetCTPForwardData.
+func (c *EthernetCTPForwardData) LayerType() gopacket.LayerType {
+	return LayerTypeEthernetCTPForwardData
+}
+
+// ForwardEndpoint returns the EthernetCTPForwardData ForwardAddress as an endpoint.
+func (c *EthernetCTPForwardData) ForwardEndpoint() gopacket.Endpoint {
+	return gopacket.NewEndpoint(EndpointMAC, c.ForwardAddress)
+}
+
+// EthernetCTPReply is the Reply layer inside EthernetCTP.  See EthernetCTP's docs for more details.
+type EthernetCTPReply struct {
+	BaseLayer
+	Function      EthernetCTPFunction
+	ReceiptNumber uint16
+	Data          []byte
+}
+
+// LayerType returns gopacket.LayerTypeEthernetCTPReply.
+func (c *EthernetCTPReply) LayerType() gopacket.LayerType {
+	return LayerTypeEthernetCTPReply
+}
+
+// Payload returns the EthernetCTP reply's Data bytes.
+func (c *EthernetCTPReply) Payload() []byte { return c.Data }
+
+func decodeEthernetCTP(data []byte, p gopacket.PacketBuilder) error {
+	c := &EthernetCTP{
+		SkipCount: binary.LittleEndian.Uint16(data[:2]),
+		BaseLayer: BaseLayer{data[:2], data[2:]},
+	}
+	if c.SkipCount%2 != 0 {
+		return fmt.Errorf("EthernetCTP skip count is odd: %d", c.SkipCount)
+	}
+	p.AddLayer(c)
+	return p.NextDecoder(gopacket.DecodeFunc(decodeEthernetCTPFromFunctionType))
+}
+
+// decodeEthernetCTPFromFunctionType reads in the first 2 bytes to determine the EthernetCTP
+// layer type to decode next, then decodes based on that.
+func decodeEthernetCTPFromFunctionType(data []byte, p gopacket.PacketBuilder) error {
+	function := EthernetCTPFunction(binary.LittleEndian.Uint16(data[:2]))
+	switch function {
+	case EthernetCTPFunctionReply:
+		reply := &EthernetCTPReply{
+			Function:      function,
+			ReceiptNumber: binary.LittleEndian.Uint16(data[2:4]),
+			Data:          data[4:],
+			BaseLayer:     BaseLayer{data, nil},
+		}
+		p.AddLayer(reply)
+		p.SetApplicationLayer(reply)
+		return nil
+	case EthernetCTPFunctionForwardData:
+		forward := &EthernetCTPForwardData{
+			Function:       function,
+			ForwardAddress: data[2:8],
+			BaseLayer:      BaseLayer{data[:8], data[8:]},
+		}
+		p.AddLayer(forward)
+		return p.NextDecoder(gopacket.DecodeFunc(decodeEthernetCTPFromFunctionType))
+	}
+	return fmt.Errorf("Unknown EthernetCTP function type %v", function)
+}