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// 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"
)
type PFDirection uint8
const (
PFDirectionInOut PFDirection = 0
PFDirectionIn PFDirection = 1
PFDirectionOut PFDirection = 2
)
// PFLog provides the layer for 'pf' packet-filter logging, as described at
// http://www.freebsd.org/cgi/man.cgi?query=pflog&sektion=4
type PFLog struct {
BaseLayer
Length uint8
Family ProtocolFamily
Action, Reason uint8
IFName, Ruleset []byte
RuleNum, SubruleNum uint32
UID uint32
PID int32
RuleUID uint32
RulePID int32
Direction PFDirection
// The remainder is padding
}
func (pf *PFLog) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
pf.Length = data[0]
pf.Family = ProtocolFamily(data[1])
pf.Action = data[2]
pf.Reason = data[3]
pf.IFName = data[4:20]
pf.Ruleset = data[20:36]
pf.RuleNum = binary.BigEndian.Uint32(data[36:40])
pf.SubruleNum = binary.BigEndian.Uint32(data[40:44])
pf.UID = binary.BigEndian.Uint32(data[44:48])
pf.PID = int32(binary.BigEndian.Uint32(data[48:52]))
pf.RuleUID = binary.BigEndian.Uint32(data[52:56])
pf.RulePID = int32(binary.BigEndian.Uint32(data[56:60]))
pf.Direction = PFDirection(data[60])
if pf.Length%4 != 1 {
return errors.New("PFLog header length should be 3 less than multiple of 4")
}
actualLength := int(pf.Length) + 3
pf.Contents = data[:actualLength]
pf.Payload = data[actualLength:]
return nil
}
// LayerType returns layers.LayerTypePFLog
func (pf *PFLog) LayerType() gopacket.LayerType { return LayerTypePFLog }
func (pf *PFLog) CanDecode() gopacket.LayerClass { return LayerTypePFLog }
func (pf *PFLog) NextLayerType() gopacket.LayerType {
return pf.Family.LayerType()
}
func decodePFLog(data []byte, p gopacket.PacketBuilder) error {
pf := &PFLog{}
return decodingLayerDecoder(pf, data, p)
}