TUN-6666: Define packet package

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

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

@@ -0,0 +1,98 @@
+// 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"
+	"errors"
+	"fmt"
+	"net"
+
+	"github.com/google/gopacket"
+)
+
+type LinuxSLLPacketType uint16
+
+const (
+	LinuxSLLPacketTypeHost      LinuxSLLPacketType = 0 // To us
+	LinuxSLLPacketTypeBroadcast LinuxSLLPacketType = 1 // To all
+	LinuxSLLPacketTypeMulticast LinuxSLLPacketType = 2 // To group
+	LinuxSLLPacketTypeOtherhost LinuxSLLPacketType = 3 // To someone else
+	LinuxSLLPacketTypeOutgoing  LinuxSLLPacketType = 4 // Outgoing of any type
+	// These ones are invisible by user level
+	LinuxSLLPacketTypeLoopback  LinuxSLLPacketType = 5 // MC/BRD frame looped back
+	LinuxSLLPacketTypeFastroute LinuxSLLPacketType = 6 // Fastrouted frame
+)
+
+func (l LinuxSLLPacketType) String() string {
+	switch l {
+	case LinuxSLLPacketTypeHost:
+		return "host"
+	case LinuxSLLPacketTypeBroadcast:
+		return "broadcast"
+	case LinuxSLLPacketTypeMulticast:
+		return "multicast"
+	case LinuxSLLPacketTypeOtherhost:
+		return "otherhost"
+	case LinuxSLLPacketTypeOutgoing:
+		return "outgoing"
+	case LinuxSLLPacketTypeLoopback:
+		return "loopback"
+	case LinuxSLLPacketTypeFastroute:
+		return "fastroute"
+	}
+	return fmt.Sprintf("Unknown(%d)", int(l))
+}
+
+type LinuxSLL struct {
+	BaseLayer
+	PacketType   LinuxSLLPacketType
+	AddrLen      uint16
+	Addr         net.HardwareAddr
+	EthernetType EthernetType
+	AddrType     uint16
+}
+
+// LayerType returns LayerTypeLinuxSLL.
+func (sll *LinuxSLL) LayerType() gopacket.LayerType { return LayerTypeLinuxSLL }
+
+func (sll *LinuxSLL) CanDecode() gopacket.LayerClass {
+	return LayerTypeLinuxSLL
+}
+
+func (sll *LinuxSLL) LinkFlow() gopacket.Flow {
+	return gopacket.NewFlow(EndpointMAC, sll.Addr, nil)
+}
+
+func (sll *LinuxSLL) NextLayerType() gopacket.LayerType {
+	return sll.EthernetType.LayerType()
+}
+
+func (sll *LinuxSLL) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
+	if len(data) < 16 {
+		return errors.New("Linux SLL packet too small")
+	}
+	sll.PacketType = LinuxSLLPacketType(binary.BigEndian.Uint16(data[0:2]))
+	sll.AddrType = binary.BigEndian.Uint16(data[2:4])
+	sll.AddrLen = binary.BigEndian.Uint16(data[4:6])
+
+	sll.Addr = net.HardwareAddr(data[6 : sll.AddrLen+6])
+	sll.EthernetType = EthernetType(binary.BigEndian.Uint16(data[14:16]))
+	sll.BaseLayer = BaseLayer{data[:16], data[16:]}
+
+	return nil
+}
+
+func decodeLinuxSLL(data []byte, p gopacket.PacketBuilder) error {
+	sll := &LinuxSLL{}
+	if err := sll.DecodeFromBytes(data, p); err != nil {
+		return err
+	}
+	p.AddLayer(sll)
+	p.SetLinkLayer(sll)
+	return p.NextDecoder(sll.EthernetType)
+}