blob: 853882fd21e71930681ceb16b254d103c14551e5 [file] [log] [blame]
Matteo Scandoloa6a3aee2019-11-26 13:30:14 -07001// Copyright 2012 Google, Inc. All rights reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the LICENSE file in the root of the source
5// tree.
6
7package layers
8
9import (
10 "encoding/binary"
11 "errors"
12
13 "github.com/google/gopacket"
14)
15
16type PFDirection uint8
17
18const (
19 PFDirectionInOut PFDirection = 0
20 PFDirectionIn PFDirection = 1
21 PFDirectionOut PFDirection = 2
22)
23
24// PFLog provides the layer for 'pf' packet-filter logging, as described at
25// http://www.freebsd.org/cgi/man.cgi?query=pflog&sektion=4
26type PFLog struct {
27 BaseLayer
28 Length uint8
29 Family ProtocolFamily
30 Action, Reason uint8
31 IFName, Ruleset []byte
32 RuleNum, SubruleNum uint32
33 UID uint32
34 PID int32
35 RuleUID uint32
36 RulePID int32
37 Direction PFDirection
38 // The remainder is padding
39}
40
41func (pf *PFLog) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
42 pf.Length = data[0]
43 pf.Family = ProtocolFamily(data[1])
44 pf.Action = data[2]
45 pf.Reason = data[3]
46 pf.IFName = data[4:20]
47 pf.Ruleset = data[20:36]
48 pf.RuleNum = binary.BigEndian.Uint32(data[36:40])
49 pf.SubruleNum = binary.BigEndian.Uint32(data[40:44])
50 pf.UID = binary.BigEndian.Uint32(data[44:48])
51 pf.PID = int32(binary.BigEndian.Uint32(data[48:52]))
52 pf.RuleUID = binary.BigEndian.Uint32(data[52:56])
53 pf.RulePID = int32(binary.BigEndian.Uint32(data[56:60]))
54 pf.Direction = PFDirection(data[60])
55 if pf.Length%4 != 1 {
56 return errors.New("PFLog header length should be 3 less than multiple of 4")
57 }
58 actualLength := int(pf.Length) + 3
59 pf.Contents = data[:actualLength]
60 pf.Payload = data[actualLength:]
61 return nil
62}
63
64// LayerType returns layers.LayerTypePFLog
65func (pf *PFLog) LayerType() gopacket.LayerType { return LayerTypePFLog }
66
67func (pf *PFLog) CanDecode() gopacket.LayerClass { return LayerTypePFLog }
68
69func (pf *PFLog) NextLayerType() gopacket.LayerType {
70 return pf.Family.LayerType()
71}
72
73func decodePFLog(data []byte, p gopacket.PacketBuilder) error {
74 pf := &PFLog{}
75 return decodingLayerDecoder(pf, data, p)
76}