mirror of https://github.com/subgraph/fw-daemon
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
75 lines
2.0 KiB
75 lines
2.0 KiB
// 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 layers
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"errors"
|
|
"github.com/google/gopacket"
|
|
)
|
|
|
|
// PPP is the layer for PPP encapsulation headers.
|
|
type PPP struct {
|
|
BaseLayer
|
|
PPPType PPPType
|
|
}
|
|
|
|
// PPPEndpoint is a singleton endpoint for PPP. Since there is no actual
|
|
// addressing for the two ends of a PPP connection, we use a singleton value
|
|
// named 'point' for each endpoint.
|
|
var PPPEndpoint = gopacket.NewEndpoint(EndpointPPP, nil)
|
|
|
|
// PPPFlow is a singleton flow for PPP. Since there is no actual addressing for
|
|
// the two ends of a PPP connection, we use a singleton value to represent the
|
|
// flow for all PPP connections.
|
|
var PPPFlow = gopacket.NewFlow(EndpointPPP, nil, nil)
|
|
|
|
// LayerType returns LayerTypePPP
|
|
func (p *PPP) LayerType() gopacket.LayerType { return LayerTypePPP }
|
|
|
|
// LinkFlow returns PPPFlow.
|
|
func (p *PPP) LinkFlow() gopacket.Flow { return PPPFlow }
|
|
|
|
func decodePPP(data []byte, p gopacket.PacketBuilder) error {
|
|
ppp := &PPP{}
|
|
if data[0]&0x1 == 0 {
|
|
if data[1]&0x1 == 0 {
|
|
return errors.New("PPP has invalid type")
|
|
}
|
|
ppp.PPPType = PPPType(binary.BigEndian.Uint16(data[:2]))
|
|
ppp.Contents = data[:2]
|
|
ppp.Payload = data[2:]
|
|
} else {
|
|
ppp.PPPType = PPPType(data[0])
|
|
ppp.Contents = data[:1]
|
|
ppp.Payload = data[1:]
|
|
}
|
|
p.AddLayer(ppp)
|
|
p.SetLinkLayer(ppp)
|
|
return p.NextDecoder(ppp.PPPType)
|
|
}
|
|
|
|
// SerializeTo writes the serialized form of this layer into the
|
|
// SerializationBuffer, implementing gopacket.SerializableLayer.
|
|
// See the docs for gopacket.SerializableLayer for more info.
|
|
func (p *PPP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
|
|
if p.PPPType&0x100 == 0 {
|
|
bytes, err := b.PrependBytes(2)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
binary.BigEndian.PutUint16(bytes, uint16(p.PPPType))
|
|
} else {
|
|
bytes, err := b.PrependBytes(1)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
bytes[0] = uint8(p.PPPType)
|
|
}
|
|
return nil
|
|
}
|