1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
/*
* Copyright (c) 2014,2019 by Farsight Security, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package dnstap
import (
"io"
"os"
)
// FrameStreamOutput implements a dnstap Output to an io.Writer.
type FrameStreamOutput struct {
outputChannel chan []byte
wait chan bool
w Writer
log Logger
}
// NewFrameStreamOutput creates a FrameStreamOutput writing dnstap data to
// the given io.Writer.
func NewFrameStreamOutput(w io.Writer) (o *FrameStreamOutput, err error) {
ow, err := NewWriter(w, nil)
if err != nil {
return nil, err
}
return &FrameStreamOutput{
outputChannel: make(chan []byte, outputChannelSize),
wait: make(chan bool),
w: ow,
log: nullLogger{},
}, nil
}
// NewFrameStreamOutputFromFilename creates a file with the name fname,
// truncates it if it exists, and returns a FrameStreamOutput writing to
// the newly created or truncated file.
func NewFrameStreamOutputFromFilename(fname string) (o *FrameStreamOutput, err error) {
if fname == "" || fname == "-" {
return NewFrameStreamOutput(os.Stdout)
}
w, err := os.Create(fname)
if err != nil {
return
}
return NewFrameStreamOutput(w)
}
// SetLogger sets an alternate logger for the FrameStreamOutput. The default
// is no logging.
func (o *FrameStreamOutput) SetLogger(logger Logger) {
o.log = logger
}
// GetOutputChannel returns the channel on which the FrameStreamOutput accepts
// data.
//
// GetOutputData satisfies the dnstap Output interface.
func (o *FrameStreamOutput) GetOutputChannel() chan []byte {
return o.outputChannel
}
// RunOutputLoop processes data received on the channel returned by
// GetOutputChannel, returning after the CLose method is called.
// If there is an error writing to the Output's writer, RunOutputLoop()
// returns, logging an error if a logger is configured with SetLogger()
//
// RunOutputLoop satisfies the dnstap Output interface.
func (o *FrameStreamOutput) RunOutputLoop() {
for frame := range o.outputChannel {
if _, err := o.w.WriteFrame(frame); err != nil {
o.log.Printf("FrameStreamOutput: Write error: %v, returning", err)
close(o.wait)
return
}
}
close(o.wait)
}
// Close closes the channel returned from GetOutputChannel, and flushes
// all pending output.
//
// Close satisifies the dnstap Output interface.
func (o *FrameStreamOutput) Close() {
close(o.outputChannel)
<-o.wait
o.w.Close()
}
|
