99 lines
2.6 KiB
Go
99 lines
2.6 KiB
Go
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// Copyright 2012 Google, Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree.
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package layers
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"net"
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"github.com/google/gopacket"
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)
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type LinuxSLLPacketType uint16
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const (
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LinuxSLLPacketTypeHost LinuxSLLPacketType = 0 // To us
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LinuxSLLPacketTypeBroadcast LinuxSLLPacketType = 1 // To all
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LinuxSLLPacketTypeMulticast LinuxSLLPacketType = 2 // To group
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LinuxSLLPacketTypeOtherhost LinuxSLLPacketType = 3 // To someone else
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LinuxSLLPacketTypeOutgoing LinuxSLLPacketType = 4 // Outgoing of any type
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// These ones are invisible by user level
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LinuxSLLPacketTypeLoopback LinuxSLLPacketType = 5 // MC/BRD frame looped back
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LinuxSLLPacketTypeFastroute LinuxSLLPacketType = 6 // Fastrouted frame
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)
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func (l LinuxSLLPacketType) String() string {
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switch l {
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case LinuxSLLPacketTypeHost:
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return "host"
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case LinuxSLLPacketTypeBroadcast:
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return "broadcast"
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case LinuxSLLPacketTypeMulticast:
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return "multicast"
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case LinuxSLLPacketTypeOtherhost:
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return "otherhost"
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case LinuxSLLPacketTypeOutgoing:
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return "outgoing"
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case LinuxSLLPacketTypeLoopback:
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return "loopback"
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case LinuxSLLPacketTypeFastroute:
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return "fastroute"
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}
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return fmt.Sprintf("Unknown(%d)", int(l))
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}
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type LinuxSLL struct {
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BaseLayer
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PacketType LinuxSLLPacketType
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AddrLen uint16
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Addr net.HardwareAddr
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EthernetType EthernetType
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AddrType uint16
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}
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// LayerType returns LayerTypeLinuxSLL.
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func (sll *LinuxSLL) LayerType() gopacket.LayerType { return LayerTypeLinuxSLL }
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func (sll *LinuxSLL) CanDecode() gopacket.LayerClass {
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return LayerTypeLinuxSLL
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}
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func (sll *LinuxSLL) LinkFlow() gopacket.Flow {
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return gopacket.NewFlow(EndpointMAC, sll.Addr, nil)
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}
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func (sll *LinuxSLL) NextLayerType() gopacket.LayerType {
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return sll.EthernetType.LayerType()
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}
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func (sll *LinuxSLL) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
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if len(data) < 16 {
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return errors.New("Linux SLL packet too small")
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}
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sll.PacketType = LinuxSLLPacketType(binary.BigEndian.Uint16(data[0:2]))
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sll.AddrType = binary.BigEndian.Uint16(data[2:4])
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sll.AddrLen = binary.BigEndian.Uint16(data[4:6])
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sll.Addr = net.HardwareAddr(data[6 : sll.AddrLen+6])
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sll.EthernetType = EthernetType(binary.BigEndian.Uint16(data[14:16]))
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sll.BaseLayer = BaseLayer{data[:16], data[16:]}
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return nil
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}
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func decodeLinuxSLL(data []byte, p gopacket.PacketBuilder) error {
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sll := &LinuxSLL{}
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if err := sll.DecodeFromBytes(data, p); err != nil {
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return err
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}
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p.AddLayer(sll)
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p.SetLinkLayer(sll)
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return p.NextDecoder(sll.EthernetType)
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}
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