+++ /dev/null
-// 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 gopacket
-
-import (
- "errors"
-)
-
-// DecodeFeedback is used by DecodingLayer layers to provide decoding metadata.
-type DecodeFeedback interface {
- // SetTruncated should be called if during decoding you notice that a packet
- // is shorter than internal layer variables (HeaderLength, or the like) say it
- // should be. It sets packet.Metadata().Truncated.
- SetTruncated()
-}
-
-type nilDecodeFeedback struct{}
-
-func (nilDecodeFeedback) SetTruncated() {}
-
-// NilDecodeFeedback implements DecodeFeedback by doing nothing.
-var NilDecodeFeedback DecodeFeedback = nilDecodeFeedback{}
-
-// PacketBuilder is used by layer decoders to store the layers they've decoded,
-// and to defer future decoding via NextDecoder.
-// Typically, the pattern for use is:
-// func (m *myDecoder) Decode(data []byte, p PacketBuilder) error {
-// if myLayer, err := myDecodingLogic(data); err != nil {
-// return err
-// } else {
-// p.AddLayer(myLayer)
-// }
-// // maybe do this, if myLayer is a LinkLayer
-// p.SetLinkLayer(myLayer)
-// return p.NextDecoder(nextDecoder)
-// }
-type PacketBuilder interface {
- DecodeFeedback
- // AddLayer should be called by a decoder immediately upon successful
- // decoding of a layer.
- AddLayer(l Layer)
- // The following functions set the various specific layers in the final
- // packet. Note that if many layers call SetX, the first call is kept and all
- // other calls are ignored.
- SetLinkLayer(LinkLayer)
- SetNetworkLayer(NetworkLayer)
- SetTransportLayer(TransportLayer)
- SetApplicationLayer(ApplicationLayer)
- SetErrorLayer(ErrorLayer)
- // NextDecoder should be called by a decoder when they're done decoding a
- // packet layer but not done with decoding the entire packet. The next
- // decoder will be called to decode the last AddLayer's LayerPayload.
- // Because of this, NextDecoder must only be called once all other
- // PacketBuilder calls have been made. Set*Layer and AddLayer calls after
- // NextDecoder calls will behave incorrectly.
- NextDecoder(next Decoder) error
- // DumpPacketData is used solely for decoding. If you come across an error
- // you need to diagnose while processing a packet, call this and your packet's
- // data will be dumped to stderr so you can create a test. This should never
- // be called from a production decoder.
- DumpPacketData()
- // DecodeOptions returns the decode options
- DecodeOptions() *DecodeOptions
-}
-
-// Decoder is an interface for logic to decode a packet layer. Users may
-// implement a Decoder to handle their own strange packet types, or may use one
-// of the many decoders available in the 'layers' subpackage to decode things
-// for them.
-type Decoder interface {
- // Decode decodes the bytes of a packet, sending decoded values and other
- // information to PacketBuilder, and returning an error if unsuccessful. See
- // the PacketBuilder documentation for more details.
- Decode([]byte, PacketBuilder) error
-}
-
-// DecodeFunc wraps a function to make it a Decoder.
-type DecodeFunc func([]byte, PacketBuilder) error
-
-// Decode implements Decoder by calling itself.
-func (d DecodeFunc) Decode(data []byte, p PacketBuilder) error {
- // function, call thyself.
- return d(data, p)
-}
-
-// DecodePayload is a Decoder that returns a Payload layer containing all
-// remaining bytes.
-var DecodePayload Decoder = DecodeFunc(decodePayload)
-
-// DecodeUnknown is a Decoder that returns an Unknown layer containing all
-// remaining bytes, useful if you run up against a layer that you're unable to
-// decode yet. This layer is considered an ErrorLayer.
-var DecodeUnknown Decoder = DecodeFunc(decodeUnknown)
-
-// DecodeFragment is a Decoder that returns a Fragment layer containing all
-// remaining bytes.
-var DecodeFragment Decoder = DecodeFunc(decodeFragment)
-
-// LayerTypeZero is an invalid layer type, but can be used to determine whether
-// layer type has actually been set correctly.
-var LayerTypeZero = RegisterLayerType(0, LayerTypeMetadata{Name: "Unknown", Decoder: DecodeUnknown})
-
-// LayerTypeDecodeFailure is the layer type for the default error layer.
-var LayerTypeDecodeFailure = RegisterLayerType(1, LayerTypeMetadata{Name: "DecodeFailure", Decoder: DecodeUnknown})
-
-// LayerTypePayload is the layer type for a payload that we don't try to decode
-// but treat as a success, IE: an application-level payload.
-var LayerTypePayload = RegisterLayerType(2, LayerTypeMetadata{Name: "Payload", Decoder: DecodePayload})
-
-// LayerTypeFragment is the layer type for a fragment of a layer transported
-// by an underlying layer that supports fragmentation.
-var LayerTypeFragment = RegisterLayerType(3, LayerTypeMetadata{Name: "Fragment", Decoder: DecodeFragment})
-
-// DecodeFailure is a packet layer created if decoding of the packet data failed
-// for some reason. It implements ErrorLayer. LayerContents will be the entire
-// set of bytes that failed to parse, and Error will return the reason parsing
-// failed.
-type DecodeFailure struct {
- data []byte
- err error
- stack []byte
-}
-
-// Error returns the error encountered during decoding.
-func (d *DecodeFailure) Error() error { return d.err }
-
-// LayerContents implements Layer.
-func (d *DecodeFailure) LayerContents() []byte { return d.data }
-
-// LayerPayload implements Layer.
-func (d *DecodeFailure) LayerPayload() []byte { return nil }
-
-// String implements fmt.Stringer.
-func (d *DecodeFailure) String() string {
- return "Packet decoding error: " + d.Error().Error()
-}
-
-// Dump implements Dumper.
-func (d *DecodeFailure) Dump() (s string) {
- if d.stack != nil {
- s = string(d.stack)
- }
- return
-}
-
-// LayerType returns LayerTypeDecodeFailure
-func (d *DecodeFailure) LayerType() LayerType { return LayerTypeDecodeFailure }
-
-// decodeUnknown "decodes" unsupported data types by returning an error.
-// This decoder will thus always return a DecodeFailure layer.
-func decodeUnknown(data []byte, p PacketBuilder) error {
- return errors.New("Layer type not currently supported")
-}
Code Review / govpp.git / blobdiff