mirror of
https://github.com/kubenetworks/kubevpn.git
synced 2025-10-12 10:40:29 +08:00
117 lines
3.4 KiB
Go
117 lines
3.4 KiB
Go
/*
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* Copyright (c) 2014 by Farsight Security, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package dnstap
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import (
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"bufio"
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"io"
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"os"
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"google.golang.org/protobuf/proto"
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)
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// A TextFormatFunc renders a dnstap message into a human readable format.
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type TextFormatFunc func(*Dnstap) ([]byte, bool)
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// TextOutput implements a dnstap Output rendering dnstap data as text.
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type TextOutput struct {
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format TextFormatFunc
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outputChannel chan []byte
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wait chan bool
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writer *bufio.Writer
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log Logger
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}
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// NewTextOutput creates a TextOutput writing dnstap data to the given io.Writer
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// in the text format given by the TextFormatFunc format.
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func NewTextOutput(writer io.Writer, format TextFormatFunc) (o *TextOutput) {
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o = new(TextOutput)
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o.format = format
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o.outputChannel = make(chan []byte, outputChannelSize)
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o.writer = bufio.NewWriter(writer)
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o.wait = make(chan bool)
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return
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}
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// NewTextOutputFromFilename creates a TextOutput writing dnstap data to a
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// file with the given filename in the format given by format. If doAppend
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// is false, the file is truncated if it already exists, otherwise the file
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// is opened for appending.
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func NewTextOutputFromFilename(fname string, format TextFormatFunc, doAppend bool) (o *TextOutput, err error) {
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if fname == "" || fname == "-" {
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return NewTextOutput(os.Stdout, format), nil
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}
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var writer io.Writer
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if doAppend {
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writer, err = os.OpenFile(fname, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
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} else {
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writer, err = os.Create(fname)
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}
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if err != nil {
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return
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}
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return NewTextOutput(writer, format), nil
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}
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// SetLogger configures a logger for error events in the TextOutput
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func (o *TextOutput) SetLogger(logger Logger) {
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o.log = logger
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}
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// GetOutputChannel returns the channel on which the TextOutput accepts dnstap data.
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//
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// GetOutputChannel satisfies the dnstap Output interface.
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func (o *TextOutput) GetOutputChannel() chan []byte {
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return o.outputChannel
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}
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// RunOutputLoop receives dnstap data sent on the output channel, formats it
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// with the configured TextFormatFunc, and writes it to the file or io.Writer
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// of the TextOutput.
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//
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// RunOutputLoop satisfies the dnstap Output interface.
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func (o *TextOutput) RunOutputLoop() {
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dt := &Dnstap{}
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for frame := range o.outputChannel {
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if err := proto.Unmarshal(frame, dt); err != nil {
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o.log.Printf("dnstap.TextOutput: proto.Unmarshal() failed: %s, returning", err)
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break
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}
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buf, ok := o.format(dt)
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if !ok {
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o.log.Printf("dnstap.TextOutput: text format function failed, returning")
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break
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}
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if _, err := o.writer.Write(buf); err != nil {
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o.log.Printf("dnstap.TextOutput: write error: %v, returning", err)
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break
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}
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o.writer.Flush()
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}
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close(o.wait)
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}
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// Close closes the output channel and returns when all pending data has been
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// written.
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//
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// Close satisfies the dnstap Output interface.
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func (o *TextOutput) Close() {
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close(o.outputChannel)
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<-o.wait
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o.writer.Flush()
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}
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