mirror of
https://github.com/kubenetworks/kubevpn.git
synced 2025-10-12 10:40:29 +08:00
116 lines
3.4 KiB
Go
116 lines
3.4 KiB
Go
/*
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* Copyright (c) 2013-2019 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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"io"
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"os"
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"time"
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)
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// MaxPayloadSize sets the upper limit on input Dnstap payload sizes. If an Input
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// receives a Dnstap payload over this size limit, ReadInto will log an error and
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// return.
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//
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// EDNS0 and DNS over TCP use 2 octets for DNS message size, imposing a maximum
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// size of 65535 octets for the DNS message, which is the bulk of the data carried
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// in a Dnstap message. Protobuf encoding overhead and metadata with some size
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// guidance (e.g., identity and version being DNS strings, which have a maximum
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// length of 255) add up to less than 1KB. The default 96KiB size of the buffer
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// allows a bit over 30KB space for "extra" metadata.
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//
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var MaxPayloadSize uint32 = 96 * 1024
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// A FrameStreamInput reads dnstap data from an io.ReadWriter.
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type FrameStreamInput struct {
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wait chan bool
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reader Reader
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log Logger
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}
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// NewFrameStreamInput creates a FrameStreamInput reading data from the given
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// io.ReadWriter. If bi is true, the input will use the bidirectional
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// framestream protocol suitable for TCP and unix domain socket connections.
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func NewFrameStreamInput(r io.ReadWriter, bi bool) (input *FrameStreamInput, err error) {
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return NewFrameStreamInputTimeout(r, bi, 0)
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}
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// NewFrameStreamInputTimeout creates a FramestreamInput reading data from the
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// given io.ReadWriter with a timeout applied to reading and (for bidirectional
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// inputs) writing control messages.
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func NewFrameStreamInputTimeout(r io.ReadWriter, bi bool, timeout time.Duration) (input *FrameStreamInput, err error) {
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reader, err := NewReader(r, &ReaderOptions{
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Bidirectional: bi,
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Timeout: timeout,
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})
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if err != nil {
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return nil, err
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}
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return &FrameStreamInput{
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wait: make(chan bool),
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reader: reader,
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log: nullLogger{},
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}, nil
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}
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// NewFrameStreamInputFromFilename creates a FrameStreamInput reading from
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// the named file.
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func NewFrameStreamInputFromFilename(fname string) (input *FrameStreamInput, err error) {
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file, err := os.Open(fname)
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if err != nil {
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return nil, err
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}
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return NewFrameStreamInput(file, false)
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}
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// SetLogger configures a logger for FrameStreamInput read error reporting.
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func (input *FrameStreamInput) SetLogger(logger Logger) {
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input.log = logger
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}
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// ReadInto reads data from the FrameStreamInput into the output channel.
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//
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// ReadInto satisfies the dnstap Input interface.
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func (input *FrameStreamInput) ReadInto(output chan []byte) {
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buf := make([]byte, MaxPayloadSize)
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for {
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n, err := input.reader.ReadFrame(buf)
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if err == nil {
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newbuf := make([]byte, n)
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copy(newbuf, buf)
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output <- newbuf
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continue
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}
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if err != io.EOF {
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input.log.Printf("FrameStreamInput: Read error: %v", err)
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}
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break
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}
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close(input.wait)
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}
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// Wait reeturns when ReadInto has finished.
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//
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// Wait satisfies the dnstap Input interface.
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func (input *FrameStreamInput) Wait() {
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<-input.wait
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}
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