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

   1 // Copyright 2012 Google, Inc. All rights reserved.
   2 //
   3 // Use of this source code is governed by a BSD-style license
   4 // that can be found in the LICENSE file in the root of the source
   5 // tree.
   6
   7 package layers
   8
   9 import (
  10         "encoding/binary"
  11         "errors"
  12         "fmt"
  13         "net"
  14
  15         "github.com/google/gopacket"
  16 )
  17
  18 type LinuxSLLPacketType uint16
  19
  20 const (
  21         LinuxSLLPacketTypeHost      LinuxSLLPacketType = 0 // To us
  22         LinuxSLLPacketTypeBroadcast LinuxSLLPacketType = 1 // To all
  23         LinuxSLLPacketTypeMulticast LinuxSLLPacketType = 2 // To group
  24         LinuxSLLPacketTypeOtherhost LinuxSLLPacketType = 3 // To someone else
  25         LinuxSLLPacketTypeOutgoing  LinuxSLLPacketType = 4 // Outgoing of any type
  26         // These ones are invisible by user level
  27         LinuxSLLPacketTypeLoopback  LinuxSLLPacketType = 5 // MC/BRD frame looped back
  28         LinuxSLLPacketTypeFastroute LinuxSLLPacketType = 6 // Fastrouted frame
  29 )
  30
  31 func (l LinuxSLLPacketType) String() string {
  32         switch l {
  33         case LinuxSLLPacketTypeHost:
  34                 return "host"
  35         case LinuxSLLPacketTypeBroadcast:
  36                 return "broadcast"
  37         case LinuxSLLPacketTypeMulticast:
  38                 return "multicast"
  39         case LinuxSLLPacketTypeOtherhost:
  40                 return "otherhost"
  41         case LinuxSLLPacketTypeOutgoing:
  42                 return "outgoing"
  43         case LinuxSLLPacketTypeLoopback:
  44                 return "loopback"
  45         case LinuxSLLPacketTypeFastroute:
  46                 return "fastroute"
  47         }
  48         return fmt.Sprintf("Unknown(%d)", int(l))
  49 }
  50
  51 type LinuxSLL struct {
  52         BaseLayer
  53         PacketType   LinuxSLLPacketType
  54         AddrLen      uint16
  55         Addr         net.HardwareAddr
  56         EthernetType EthernetType
  57 }
  58
  59 // LayerType returns LayerTypeLinuxSLL.
  60 func (sll *LinuxSLL) LayerType() gopacket.LayerType { return LayerTypeLinuxSLL }
  61
  62 func (sll *LinuxSLL) CanDecode() gopacket.LayerClass {
  63         return LayerTypeLinuxSLL
  64 }
  65
  66 func (sll *LinuxSLL) LinkFlow() gopacket.Flow {
  67         return gopacket.NewFlow(EndpointMAC, sll.Addr, nil)
  68 }
  69
  70 func (sll *LinuxSLL) NextLayerType() gopacket.LayerType {
  71         return sll.EthernetType.LayerType()
  72 }
  73
  74 func (sll *LinuxSLL) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
  75         if len(data) < 16 {
  76                 return errors.New("Linux SLL packet too small")
  77         }
  78         sll.PacketType = LinuxSLLPacketType(binary.BigEndian.Uint16(data[0:2]))
  79         sll.AddrLen = binary.BigEndian.Uint16(data[4:6])
  80
  81         sll.Addr = net.HardwareAddr(data[6 : sll.AddrLen+6])
  82         sll.EthernetType = EthernetType(binary.BigEndian.Uint16(data[14:16]))
  83         sll.BaseLayer = BaseLayer{data[:16], data[16:]}
  84
  85         return nil
  86 }
  87
  88 func decodeLinuxSLL(data []byte, p gopacket.PacketBuilder) error {
  89         sll := &LinuxSLL{}
  90         if err := sll.DecodeFromBytes(data, p); err != nil {
  91                 return err
  92         }
  93         p.AddLayer(sll)
  94         p.SetLinkLayer(sll)
  95         return p.NextDecoder(sll.EthernetType)
  96 }