diff options
Diffstat (limited to 'vendor/github.com/google/gopacket/layers/arp.go')
-rw-r--r-- | vendor/github.com/google/gopacket/layers/arp.go | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/vendor/github.com/google/gopacket/layers/arp.go b/vendor/github.com/google/gopacket/layers/arp.go new file mode 100644 index 0000000..49e05ac --- /dev/null +++ b/vendor/github.com/google/gopacket/layers/arp.go @@ -0,0 +1,109 @@ +// Copyright 2012 Google, Inc. All rights reserved. +// Copyright 2009-2011 Andreas Krennmair. 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" + + "github.com/google/gopacket" +) + +// Potential values for ARP.Operation. +const ( + ARPRequest = 1 + ARPReply = 2 +) + +// ARP is a ARP packet header. +type ARP struct { + BaseLayer + AddrType LinkType + Protocol EthernetType + HwAddressSize uint8 + ProtAddressSize uint8 + Operation uint16 + SourceHwAddress []byte + SourceProtAddress []byte + DstHwAddress []byte + DstProtAddress []byte +} + +// LayerType returns LayerTypeARP +func (arp *ARP) LayerType() gopacket.LayerType { return LayerTypeARP } + +// DecodeFromBytes decodes the given bytes into this layer. +func (arp *ARP) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error { + arp.AddrType = LinkType(binary.BigEndian.Uint16(data[0:2])) + arp.Protocol = EthernetType(binary.BigEndian.Uint16(data[2:4])) + arp.HwAddressSize = data[4] + arp.ProtAddressSize = data[5] + arp.Operation = binary.BigEndian.Uint16(data[6:8]) + arp.SourceHwAddress = data[8 : 8+arp.HwAddressSize] + arp.SourceProtAddress = data[8+arp.HwAddressSize : 8+arp.HwAddressSize+arp.ProtAddressSize] + arp.DstHwAddress = data[8+arp.HwAddressSize+arp.ProtAddressSize : 8+2*arp.HwAddressSize+arp.ProtAddressSize] + arp.DstProtAddress = data[8+2*arp.HwAddressSize+arp.ProtAddressSize : 8+2*arp.HwAddressSize+2*arp.ProtAddressSize] + + arpLength := 8 + 2*arp.HwAddressSize + 2*arp.ProtAddressSize + arp.Contents = data[:arpLength] + arp.Payload = data[arpLength:] + return nil +} + +// SerializeTo writes the serialized form of this layer into the +// SerializationBuffer, implementing gopacket.SerializableLayer. +// See the docs for gopacket.SerializableLayer for more info. +func (arp *ARP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error { + size := 8 + len(arp.SourceHwAddress) + len(arp.SourceProtAddress) + len(arp.DstHwAddress) + len(arp.DstProtAddress) + bytes, err := b.PrependBytes(size) + if err != nil { + return err + } + if opts.FixLengths { + if len(arp.SourceHwAddress) != len(arp.DstHwAddress) { + return errors.New("mismatched hardware address sizes") + } + arp.HwAddressSize = uint8(len(arp.SourceHwAddress)) + if len(arp.SourceProtAddress) != len(arp.DstProtAddress) { + return errors.New("mismatched prot address sizes") + } + arp.ProtAddressSize = uint8(len(arp.SourceProtAddress)) + } + binary.BigEndian.PutUint16(bytes, uint16(arp.AddrType)) + binary.BigEndian.PutUint16(bytes[2:], uint16(arp.Protocol)) + bytes[4] = arp.HwAddressSize + bytes[5] = arp.ProtAddressSize + binary.BigEndian.PutUint16(bytes[6:], arp.Operation) + start := 8 + for _, addr := range [][]byte{ + arp.SourceHwAddress, + arp.SourceProtAddress, + arp.DstHwAddress, + arp.DstProtAddress, + } { + copy(bytes[start:], addr) + start += len(addr) + } + return nil +} + +// CanDecode returns the set of layer types that this DecodingLayer can decode. +func (arp *ARP) CanDecode() gopacket.LayerClass { + return LayerTypeARP +} + +// NextLayerType returns the layer type contained by this DecodingLayer. +func (arp *ARP) NextLayerType() gopacket.LayerType { + return gopacket.LayerTypePayload +} + +func decodeARP(data []byte, p gopacket.PacketBuilder) error { + + arp := &ARP{} + return decodingLayerDecoder(arp, data, p) +} |