| Naveen Sampath | 04696f7 | 2022-06-13 15:19:14 +0530 | [diff] [blame] | 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 | AddrType uint16 |
| 58 | } |
| 59 | |
| 60 | // LayerType returns LayerTypeLinuxSLL. |
| 61 | func (sll *LinuxSLL) LayerType() gopacket.LayerType { return LayerTypeLinuxSLL } |
| 62 | |
| 63 | func (sll *LinuxSLL) CanDecode() gopacket.LayerClass { |
| 64 | return LayerTypeLinuxSLL |
| 65 | } |
| 66 | |
| 67 | func (sll *LinuxSLL) LinkFlow() gopacket.Flow { |
| 68 | return gopacket.NewFlow(EndpointMAC, sll.Addr, nil) |
| 69 | } |
| 70 | |
| 71 | func (sll *LinuxSLL) NextLayerType() gopacket.LayerType { |
| 72 | return sll.EthernetType.LayerType() |
| 73 | } |
| 74 | |
| 75 | func (sll *LinuxSLL) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error { |
| 76 | if len(data) < 16 { |
| 77 | return errors.New("Linux SLL packet too small") |
| 78 | } |
| 79 | sll.PacketType = LinuxSLLPacketType(binary.BigEndian.Uint16(data[0:2])) |
| 80 | sll.AddrType = binary.BigEndian.Uint16(data[2:4]) |
| 81 | sll.AddrLen = binary.BigEndian.Uint16(data[4:6]) |
| 82 | |
| 83 | sll.Addr = net.HardwareAddr(data[6 : sll.AddrLen+6]) |
| 84 | sll.EthernetType = EthernetType(binary.BigEndian.Uint16(data[14:16])) |
| 85 | sll.BaseLayer = BaseLayer{data[:16], data[16:]} |
| 86 | |
| 87 | return nil |
| 88 | } |
| 89 | |
| 90 | func decodeLinuxSLL(data []byte, p gopacket.PacketBuilder) error { |
| 91 | sll := &LinuxSLL{} |
| 92 | if err := sll.DecodeFromBytes(data, p); err != nil { |
| 93 | return err |
| 94 | } |
| 95 | p.AddLayer(sll) |
| 96 | p.SetLinkLayer(sll) |
| 97 | return p.NextDecoder(sll.EthernetType) |
| 98 | } |